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Liberia from 1912 to 1930
Daniel Edward Howard was the President of Liberia from 1912 to 1920 and had to deal with wars on all fronts - internally and externally. The finances of the State were so bad that the pay of government employees was suspended for months a at time.
The European war, World War I, resulted in the trade between Liberia and Britain, France and the United States reduced to almost zero due to the German submarine blockade. In 1917, Liberia joined the Allies against Germany and liquidated a property of German nationals in Liberia. The money generated from this liquidation was deposited into the Liberian government bank account to compensate for loss of revenue from the blockade. The war ended in 1920, and Liberia's Legislature ratified the Treaty of Versailles.
Charles D. B. King became Liberia's President in 1920 and serve for 10 years. Since the war had caused the financial situation of Liberia to be in such bad condition, President King and a commission embarked upon a journey to the United States to get assistance in paying of her debts and straightening her financial affairs. They arrived in March of 1921, shortly after President Harding had taken office. The State Department and Treasury had all new personnel and the Congress had many new congressmen.
Congress had suspended all foreign credit and extension of foreign loans, even though the State department was sympathetic with the request from the Liberian delegation. Negotiation drag on until October before the State Department finally granted Liberia a loan for five million dollars. The commission was greatly relieved because the long, painful negotiations were complete. However, great disappointment followed when the U.S. Congress failed to ratify the agreement.
In 1923, the Firestone Rubber Company explored the possibilities of establishing a rubber plantation in Liberia. In fact, the conditions in Liberia are ideal for rubber trees and a one million acre plantation was established in Harbal. This was a great economic boost for Liberia due to the employment of 25,000 workers. A loan for 5 million dollars was secured shortly afterwards that allowed Liberia to consolidate and bond all internal and external depts. In addition, certain public works were to be developed with money from this loan. One of which was the establishment of Liberia's first radio station which broadcast its first message in 1927.
While the nation was feeling so good about the recent events, tragedy occurred in November of 1927 when a ship carrying soldiers sank near the Monrovian port killing thirty including former President Daniel Howard and his son.
President King and his vice-president resigned from office in 1930 admits scandal resulting for the accusations of slavery and forced labor. In 1921, the Liberian legislature approved a provision prohibiting the export of labor to the Island of Fernando Po. These laborers were said to be forced into work. The League of Nations established a commission to determine the extent of forced labor and slavery still practiced by in Liberia. The Liberian government also appointed a commission to investigate these allegations. It was found that forced labor was used for construction of certain public works such as roads in the interior. And certain tribes did practice domestic servitude that could be considered as slavery. These practices were ordered to cease but some politicians and leading citizen demanded that the King administration step down. |
In the philosophy of Plato and Aristotle the active, determining principle of a thing. The term was traditionally used to translate Plato's eidos, by which he meant the permanent reality that makes a thing what it is, in contrast to the particulars that are finite and subject to change. Each form is the pattern of a particular category of thing in the world; thus, there are forms of human, stone, shape, colour, beauty, and justice. Whereas the physical world, perceived with the senses, is in constant flux and knowledge derived from it restricted and variable, the realm of forms, apprehensible only by the mind, is eternal and changeless. Particular things derive what reality they have by “participating” in, or imperfectly copying, the forms. Aristotle rejected the abstract Platonic notion of form and argued that every sensible object consists of both matter and form, neither of which can exist without the other. For Aristotle, the matter of a thing consists of those of its elements which, when the thing has come into being, may be said to have “become” it; the form of a thing is the arrangement or organization through which such elements have become the thing in question. Thus a certain lump of bronze is the matter that, given a certain form, becomes a statue or, given another, becomes a sword. The Aristotelian concept of form was adapted and developed by St. Thomas Aquinas and other scholastic philosophers. The Enlightenment philosopher Immanuel Kant used the notion of form to describe the mentally imposed conditions of sensible experience, namely space and time.
Learn more about form with a free trial on Britannica.com. |
Architecture of Global Positioning System (GPS)
GPS or Global positioning system is a satellite based navigation system that provides the exact location and time of an object at any place in the globe in all weather conditions. This is one of the best example of technological advancement in the field of science and technology. The basic concept of GPS technology involves the transmission of signals by the satellites that includes three things: the time at which the message was transmitted by the receiver, the orbital information and the general system health and rough orbits of all GPS satellites.
To run all the system of GPS technology properly, highly advance architecture of GPS has been developed that includes three major segments called the space segment (SS), control segment (CS) and a user segment (US). The first two segments i.e. Space segment and control segment is being controlled and operated by the U.S. Air force. The GPS satellites transmits the signals from the space which are received by the data receivers on the earth which are then used to calculate the three-dimensional location (latitude, longitude, and altitude) of the object along with time.
If we look upon the architectural framework of Global positioning system, the space segment consist of 24 operational satellites and 3 more satellites along with the payload adapters to the boosters required to launch them into orbit. These satellites are placed in the medium earth orbit. The central segment consists of a master control station, an alternate master control station, and a host of dedicated and shared ground antennas and monitor stations. The last segment, user segment constitutes thousands of military users and million of commercial and civilian users. The military users uses the GPS Precise Positioning Service while the others uses the Standard Positioning Service of GPS.
The space segment (SS) comprises the GPS satellites, or Space Vehicles (SV) in GPS parlance. The 24 GPS satellites in the GPS design is distributed into eight each in three circular orbits. Later it was divided into six orbital planes with four satellites each. Though, the orbits are centered on the Earth, they don't rotate with the earth and are fixed with respect to the distant stars. These orbits are arranged in such a way that at least six satellites should always lie within the line of sight from every part of earth surface. For this, four satellites are unevenly spaced within each orbit with angular difference of each orbit being 30, 105, 120, and 105 degrees apart. Thus, making a sum total of 360 degree.
A control system of GPS is completed by the combination of a master control station (MCS), an alternate master control station, four dedicated ground antennas and six dedicated monitor stations. The control segment is responsible for the proper functioning of all the operations of global positioning system such as changing the unhealthy satellites with a healthy one if any satellite fails suddenly. It also provides the operational capability to the system that helps the global GPS users and keeps the GPS system operational and functional within specification every time. In addition to that the control segment is responsible for the security issues of the system also.
The user segment comprises of thousands of U.S. and allied military users who uses the secure GPS Precise Positioning Service, and millions of civil, commercial and scientific users who uses the Standard Positioning Service of global positioning system. Commonly, the GPS receivers are composed of an antenna, which are tuned to the frequencies that are transmitted by the orbital GPS satellites, receiver-processors, and a highly stable clock called a crystal oscillator. In addition to that they consists of a display that the information about the location and speed to the user. A receiver is generally known by its number of channels which signifies how many satellites it can monitor at a time. Earlier, the number was limited to four or five but now a days the number of channels for a receiver has increased to 12 to 20.
This is how a Global positioning system is designed to get an accurate information about the location and speed of an object and is used for several purposes and has proved very useful in today's world.
We request you to call us at +91 9313063554 or email us at firstname.lastname@example.org for you software development needs. |
Affective disorders are a set of psychiatric diseases, also called mood disorders. The main types of affective disorders are depression, bipolar disorder, and anxiety disorder. Symptoms vary by individual, but they typically affect mood. They can range from mild to severe.
A psychiatrist or other trained mental health professional can diagnose an affective disorder. This is done with a psychiatric evaluation. Affective disorders can be disruptive to your life. However, there are effective treatments available, including both medication and psychotherapy.
Depression, or major depressive disorder, is characterized by feelings of extreme sadness and hopelessness. It is more than simply feeling down for a day or two. If you have depression, you may experience episodes that last for several days or even weeks. A milder form of depression is called dysthymia.
Bipolar disorder means having periods of depression, and periods of mania. Mania is when you feel extremely positive and active. This may sound good, but mania also makes you feel irritable, aggressive, impulsive, and even delusional. There are different types of bipolar, classified by the severity of depression and mania, as well as by how often mood swings occur.
There are several different types of anxiety disorders. All are characterized by feelings of nervousness, anxiety, and even fear. They are:
- social anxiety: anxiety caused by social situations
- post-traumatic stress disorder: anxiety, fear, and flashbacks caused by a traumatic event
- generalized anxiety disorder: anxiousness and fear in general, with no particular cause
- panic disorder: anxiety that causes panic attacks
- obsessive-compulsive disorder: obsessive thoughts that cause anxiety and compulsive actions
The symptoms of affective disorders can vary greatly. There are some common signs, however, for each of the three main types.
- prolonged sadness
- irritability or anxiety
- lethargy and lack of energy
- lack of interest in normal activities
- major changes in eating and sleeping habits
- difficulty concentrating
- feelings of guilt
- aches and pains that have no physical explanation
- suicidal thoughts
- unusual and chronic mood swings
- during depression, symptoms similar to those for major depressive disorder
- during mania, less sleep and feelings of exaggerated self-confidence, irritability, aggression, self-importance, impulsiveness, recklessness, or in severe cases delusions or hallucinations
- constant worry
- obsessive thoughts
- trouble concentrating
- difficulty sleeping
- shortness of breath and rapid heart rate
The causes of affective disorders are not fully understood. Neurotransmitters, or brain chemicals, play a major role in affecting mood. When they are imbalanced in some way, or do not signal properly in the brain, an affective disorder can be the result. What causes the imbalance is not fully known.
Life events can trigger affective disorders. A traumatic event or personal loss can cause depression or another affective disorder, but it may not be permanent. Use of alcohol and drugs is also a risk factor.
There also seems to be a genetic factor. If someone in your family has one of these disorders, you are at a greater risk for developing one as well. This means that they are hereditary. However, you are not guaranteed to have an affective disorder just because a family member has one.
There are no medical tests to diagnose affective disorders. To make a diagnosis, a psychiatrist or other trained mental health professional can give you a psychiatric evaluation. They follow set guidelines. Expect to be asked about your symptoms.
There are two main treatments for affective disorders: medication and therapy. Treatment usually involves a combination of both. There are many different antidepressant medications available. You may need to try several before you find one that helps relieve your symptoms without too many side effects.
Psychotherapy in addition to medication is also an important part of treatment for affective disorders. It can help you learn to cope with your disorder and help change your behaviors that contribute to it.
With appropriate and long-term treatment, the outlook for having an affective disorder is good. It is important to understand that, in most cases, these are chronic conditions that have to be treated over the long-term. While some cases are severe, most people with affective disorders who are using treatment can live a normal life. |
Arawak and Carib Indians lived on the northern edges of South America
for centuries. In 1498, the Spanish
explorer, Alonso de Ojeda (accompanying Columbus on his second voyage to the New World
) is generally considered the first European to discover what is now called Suriname.
Dutch settlement on the continent began in the early 17th century at the mouths of several rivers between present-day Georgetown, Guyana
- and Cayenne, French Guiana
; with Suriname becoming a Dutch colony in 1667.
Even though the land was briefly held by the English, it was the Dutch that controlled and influenced Suriname for almost 300 years.
Over time, the Dutch colonial plantations began to decline, as the distant Dutch government was supplying less financial support to its colony.
In the early 20th century - a turn around - when the American
firm ALCOA invested in the indigenous bauxite deposits, and Suriname's economy surged, and it became the world's leading supplier of same.
Later in the century, on the long road to independence, Suriname became an autonomous part of the Kingdom of the Netherlands
, and finally gained independence on November 25, 1975.
Five years later the civilian government was replaced by a military regime that soon declared Suriname a socialist republic. It continued to rule through a succession of nominally civilian administrations until 1987, when international pressure finally forced a democratic election.
In 1989, the military replaced (overthrew
) the civilian government, but a democratically-elected government returned to power in 1991, and remains to this day. |
The differences between the Spanish language of Spain and Spanish from Latin America are something like the differences between British English and American English. People from the Spanish-speaking world can communicate with others as easily as people throughout the English-speaking world can. Although there are differences between Spanish from Spain and Latin American Spanish – particularly relating to pronunciation – they do not prevent mutual intelligibility. Here you can experience the regional differences and dialects from all the Spanish World.
Latin American dialects are noted for the pronunciation of each letter and their strong "r" sounds. This kind of Spanish was spoken in Spain in the XVIth and XVIIth centuries, and was taken to the Americas by the early colonists.
However, the Spanish of North of Madrid in Spain, called Castilian, developed characteristics that never reached the New World. Castilian is the Spanish equivalent of High German or the Queen's English. The differences with Latin American Spanish include the pronunciation of "ci" and "ce" as "th". In Castile, "gracias" (thank you) becomes "gratheas" (as opposed to "gras-see-as" in Latin America). Also, speakers in some areas like Argentina often pronounce the ll and y like the "s" in "measure." In some areas, you will hear speakers drop s sounds, so está sounds like etá. In some argentinian and Uruguayan areas, the j sounds like the "ch" in "loch".
Another difference is the use of the word "vosotros" (plural you) as the informal form of "you" in Spain. Latin Americans never use "vosotros," favoring "ustedes" instead.
But if you avoid slang or extreme colloquialisms, standard educated Castilian Spanish is understood anywhere in the Spanish-speaking world. |
We are often impressed by a person who is the “first” to do something. Edmund Hillary and Tenzing Norgay are renowned as the first to reach the summit of Mt. Everest in 1953. Christopher Columbus is famous for his success as the first to reach the Americas in 1492. Magellan’s expedition was the first to circumnavigate the globe in the 16th century. This desire to be “first” is at the forefront of exploration, but being first is a matter of perspective. Columbus and the leaders of 15th century Europe did not know about the Vikings who established a settlement in what is now Newfoundland, Canada, 500 years before Columbus arrived.
Captain Malaspina speculated about how the indigenous people of North America first arrived by migrating on rafts and via a land bridge. However, most European explorers did not consider that the presence of First Nations communities meant that someone had definitely arrived before them! Primacy (and therefore the right to claim territory and resources) was a matter that only included other European powers. This has had a great impact on how we are taught history. Accounts of discovery that are written down are the only ones many cultures are willing to believe.
Some researchers have presented other views of history. Norwegian Tor Heyerdahl set out to prove his theory that prehistoric cultures and ancient civilizations had contact via ocean-going vessels, and that they travelled, populating new regions of the globe. In 1947, he and his crew made the journey from Peru to Polynesia aboard the Kon-Tiki. In 1970, he successfully sailed the reed ship RA II from Morocco to Barbados to show it was possible that Africans could have reached the Americas in ancient craft. Not everyone agrees with such theories, but testing them is a form of exploration in itself. |
The Maginot Line dominated French military thinking in the inter-war years. The Maginot Line was a vast fortification that spread along the French/German border but became a military liability when the Germans attacked France in the spring of 1940 using blitzkrieg – a tactic that completely emasculated the Maginot Line’s purpose.
France had suffered appalling damage to both men and buildings in World War One. After Versailles in 1919, there was a clear intention on the part of the French that France should never have to suffer such a catastrophe again. After 1920, those men in both political positions and the military favoured adopting a military strategy that would simply stop any form of German invasion again.
Senior figures in the French military, such as Marshall Foch, believed that the German anger over Versailles all but guaranteed that Germany would seek revenge. The main thrust of French military policy, as a result, was to embrace the power of the defence.
As head of the armed forces, Marshall Petain commissioned a number of teams to come up with a solution to the French dilemma. Three schools of thought developed:
1) That France should adopt a policy of offence as opposed to defence. One of the main supporters of this was Charles de Gaulle. He wanted France to develop an army based on speed, mobility and mechanised vehicles. There were few who supported his ideas as many in the military saw them as aggressive and likely to provoke a response as opposed to guard against a German one.
2) France should base its military in a line of small heavily defended areas from which a counter-attack could be launched if required. Marshall Joffre favoured this idea.
3) France should build a long line of fortifications along the whole French/German border which would be both long and deep into France. Marshall Petain favoured this idea.
Petain had come out of World War One with a degree of credit and with his backing the idea of a long and deep defensive barrier gained political support. In this, Petain was supported by Andre Maginot, the Minister of War.
Maginot was Minister of War between 1922 and 1924. However, even after 1924, Maginot was involved in the project. In 1926, Maginot and his successor, Paul Painleve, got the funding for a body that was known as the Committee of Frontier Defence (CFD). The CFD was given the funding to build three sections of an experimental defence line – based on what Petain had recommended - which was to develop into the Maginot Line.
In 1929, Maginot returned to government office. He gained more money from the government to build a full-scale defence barrier along the German border. He overcame any opposition to his plan very simply – the fortification, he argued, would end any chance there was that France would suffer the terrible bloodshed of 1914 -1918 should there ever be another war. Also, in 1930, French troops that had occupied the Rhineland as part of the Versailles Treaty, had to leave the area that bordered onto France – this at a time when the Nazi Party and Hitler were making real headway in Germany.
Maginot had a number of sound military arguments on his side:
Ø The Line would hinder any German attack for so long that the bulk of the large French army would be fully mobilised to counter the attack.
Ø The troops stationed in the Line would also be used to fight against the invading Germans should they get through any one part of the Line and attack them from the rear.
Ø All the fighting would take place near to the French/German border so that there would be minimal damage to property.
Ø The Ardennes in the north would act as a natural continuation of the man-made Line as it was considered impenetrable, so the Line need not go all the way to the Channel.
Work on the Maginot Line proper started in 1930 when the French government gave a grant of 3 billion francs for its building. The work continued until 1940. Maginot himself died in 1932, and the line was named after him in his honour.
What exactly was the Maginot Line?
It was not a continuous line of forts as some believe. In parts, especially in the south from Basle to Haguenau, it was nothing more than a series of outposts as the steep geography of the region and the River Rhine provided its own defence between France and Germany. The Line comprised of over 500 separate buildings but was dominated by large forts (known as ‘ouvrages’) which were built about nine miles from each other. Each ouvrage housed 1000 soldiers with artillery. Between each ouvrage were smaller forts which housed between 200 to 500 men depending on their size.
There were 50 ouvrages in total along the German border. Each one had the necessary fire power to cover the two nearest ouvrages to the north and south. They were protected by reinforced steel that was inches deep and capable of taking a direct hit from most known artillery fire.
The smaller forts were obviously not as well armed or protected as the ouvrages but they were still well built. They were further protected by minefields and anti-tank ditches. Forward defence lines were designed to give the defenders a good warning of an impending attack. In theory, the Maginot Line was capable of creating a massive continuous line of fire that should have devastated any attack.
The Maginot Line was such an impressive piece of construction that dignitaries from around the world visited it.
However, the Maginot Line had two major failings – it was obviously not mobile and it assumed that the Ardennes was impenetrable. Any attack that could get around it would leave it floundering like a beached whale. Blitzkrieg was the means by which Germany simply went around the whole Line. By doing this, the Maginot Line was isolated and the plan that soldiers in the Line could assist the mobilised French troops was a non-starter. The speed with which Germany attacked France and Belgium in May 1940, completely isolated all the forts. The German attack was code-named “cut-of-the-sickle” (Sichlschnitt) – an appropriate name for the attack.
German Army Group B attacked through the Ardennes – such an attack was believed to be impossible by the French. One million men and 1,500 tanks crossed the seemingly impenetrable forests in the Ardennes. The Germans wanted to drive the Allies to the sea. Once the Maginot Line had been isolated it had little military importance and the Germans only turned their attention to it in early June 1940. Many of the ouvrages surrendered after the government signed its surrender with Germany – few had to be captured in battle, though some forts did fight the Germans. One in seven French divisions was a fortress division - so the Maginot Line took out 15% of the French Army. Though not a huge figure, these men may have had an impact on the advance of the Germans - or at least got evacuated at Dunkirk to fight another time.
After the war, parts of the Maginot Line were repaired and modernised to provide post-war France with more defence. Some of the forts were supposedly made nuclear war proof. However, many parts of the Maginot Line fell into disrepair and remain so.
The Maginot Line had its critics and supporters. The critics had a vast amount of evidence to support their views. However, an argument was put forward that the Maginot Line was a success and that its failure was a failure of planning in that the Line ended at the Belgium border. If the Maginot Line had been built all along the French/Belgium border, the outcome in the spring of 1940 may have been very different as the Germans would have had to go through a major fortification as opposed to going round it. It all senses, this is a superfluous argument as the Maginot Line did not go round Belgium’s border whereas the German military did go through the Ardennes therefore neutralising the Maginot Line. |
Just How Earth-like is the Newest Planet?
Astrobiology Magazine — In the land rush known as extrasolar planet hunting, the most prized real estate is advertised as "Earth-like." On Monday, June 13, scientists raced to plant their flag on a burning hunk of rock orbiting a red star.
This newly discovered planet is about seven times the mass of Earth, and therefore the smallest extrasolar planet found to orbit a main sequence, or "dwarf" star (stars, like our sun, that burn hydrogen).
There are even smaller planets known to exist beyond our solar system, but they have the misfortune to encircle pulsars, those rapidly spinning husks of dying stars. Such planets aren’t thought to be remotely habitable, due to the intense radiation emitted by pulsars.
Planets that are ten Earth masses or less are thought to be rocky, while more massive planets are probably gaseous, since their stronger gravity means they collect and retain more gas during planetary formation. 155 extrasolar planets have been found so far, but most of them have masses that are more comparable to gaseous Jupiter than rocky Earth (Jupiter is 318 times the mass of Earth).
Although this new planet is advertised as Earth-like because of its relatively low mass, earthlings wouldn’t want to rent a house there any time soon. For one thing, the house would melt. The surface temperatures estimated for this planet – 200 to 400 degrees Celsius (400 to 750 degrees Fahrenheit) – are due to the planet’s kissing-close distance from its star.
The planet resides a mere 0.021 AU from the star Gliese 876 (1 AU is the distance between the Earth and the sun), and completes an orbit in less then two Earth days. The closest planet to the sun in our own solar system – blazing hot Mercury – is nearly 20 times further away, orbiting at about 0.4 AU.
"Because the planet is in a two-day orbit, it is heated to oven-like temperatures, so we do not expect life," says science team member Paul Butler of the Carnegie Institution of Washington.
In our solar system, the habitable zone – the temperate region where water could exist as a liquid on a planet’s surface – is roughly 0.95 to 1.37 AU, or between the orbits of Venus and Mars. The star Gliese 876 is about 600 times less luminous than our sun, so the proposed habitable zone is much closer in, roughly between 0.06 and 0.22 AU.
At 0.021 AU, the new planet is too close to the star to be in the habitable zone, and it also is subjected to greater amounts of high energy radiation like ultraviolet light and X-rays. While red dwarfs like Gliese 876 emit lower levels of UV than stars like our sun, they do emit violent X-ray flares.
Another complication from such a close orbit is that the planet may be tidally locked, with the same side of the planet always facing the star. Unless there is a substantial atmosphere to distribute heat, one side of the planet will be overcooked while the other will remain cold.
Gliese 876 is thought to be about 11 billion years old, making it more than twice as old as our sun. But in a way, Gliese is a teenager to our sun’s middle-aged adult. G-class stars like our sun live about 10 billion years, while M-class red dwarfs are thought to live for 100 billion years (older than the age of the universe!).
Science team member Geoff Marcy of the University of California, Berkeley, says that M stars take a long time to cool off and shrink down to their main sequence size and luminosity. He says that if the planet migrated inwards to its present day close orbit, it probably made this move during the first few million years, and then was subjected to much more radiation than at present for hundreds of millions of years.
Gliese 876 is thought to be metal-poor (to an astronomer, any element heavier than hydrogen and helium is classified as a "metal"). The formation of planets may be related to the metallicity of the star, since both the star and the planets form from the same original material. So a rocky planet like the Earth, made out of elements such as silicates and iron, is expected to orbit a star that is metal-rich.
Despite being metal-poor, Gliese 876 is a multiple planet system. Two gas giant planets are known to orbit Gliese 876: the outermost planet is nearly twice the mass of Jupiter, and orbits at 0.21 AU; the middle planet is about half the mass of Jupiter, orbiting at 0.13 AU.
"The whole planetary system is sort of a miniature of our solar system," says Marcy. "The star is small, the orbits are small, and in closer is the smallest of them, just as the architecture is in our own solar system, with the smallest planets orbiting inward of the giants."
We have a lot more elbow room in our solar system. Mercury is further away from the sun than the distances of all these planets combined. The planets in the Gliese 876 system are so close together, they gravitationally interact with each other. This sort of gravitational tug of war was how the scientists were able to detect the planets in the first place.
Over the course of an orbit, planets will gravitationally pull on their star from different sides. Scientists measure the resulting shift in star light to determine the existence of orbiting planets.
To learn more about Gliese 876′s smallest planet, scientists would need to use another planet-hunting technique called transit photometry. This method looks at how a star’s light seems to dip when a planet passes in front of the star from our field of view. The eclipse of the orbiting planet allows astronomers to determine that planet’s mass and radius. Pinning down those numbers indicates the planet’s density, which then suggests what the planet is made of, and whether the planet is rocky or gaseous.
Transit photometry can’t be used to tell us anything about planets orbiting Gliese 876, however, because the system is inclined 50 degrees from our point of view. This angle means the planets won’t block any of the starlight that reaches Earth.
Red dwarfs are the most common type of star in our galaxy, comprising about 70 percent of all stars. Yet out of the 150 red dwarfs they have studied over the years, Marcy and Butler only have found planets orbiting two of them. Because most of the planets found so far are gas giants, this could mean that red dwarfs are less apt to harbor those kinds of worlds.
Marcy says they will continue to monitor Gliese 876 for any hints of a fourth or fifth planet. "This will definitely be one of our favorite stars from now on."
A Race to the Finish Line
The research paper describing this discovery has been submitted to the Astrophysical Journal. The scientists say they received a favorable preliminary referee’s report, and they expect their paper will be accepted and then published in a few months. During Monday’s press conference, the scientists were asked why they decided to publicize their finding now, before the paper had been accepted for publication. Was it done to beat out other planet hunters who might be hot on their heels?
Marcy replied that they wanted to prevent news of their discovery from leaking out. "We knew about it three years ago, we’ve been following it quietly, carefully, guarding the secret while we double and triple checked. Then about a month ago I talked with Michael Turner here, people at NSF (National Science Foundation), and jointly we decided that this discovery was so extraordinary, maybe what you would call a milestone in planetary science, that it was difficult to imagine keeping the lid on this for very much longer. So we decided that rather than have it leak out to the news media, and be dribbled around, with one newspaper learning about it early and so on, that it would be better to quickly announce this."
Marcy then launched into a defense for why he believed their finding is correct, and he was quickly backed by his fellow team members. However, the accuracy of their finding had not been questioned. Perhaps their early announcement, combined with the need for secrecy beforehand, is evidence of the intense competition that has marked planet hunting since the beginning.
The first extrasolar planet discovery was announced October 5, 1995 by Michel Mayor and Didier Queloz of the Geneva Observatory, and Marcy and Butler confirmed the observations the following week. A recent example of the competition to grab other extrasolar planet "firsts" occurred last summer, when on August 25, 2004, Mayor, Nuno Santos, and colleagues announced the discovery of the first extrasolar Neptune-mass planet — at the time the smallest extrasolar planet known to orbit a sun-like star. This announcement came less than a week before two other Neptune-mass planet discoveries were announced by Marcy and Butler.
Mayor and his colleagues also have studied Gliese 876. At an astronomy conference in June 1998, Mayor and Marcy each independently announced the detection of the more massive gas giant orbiting this star. Marcy and Butler were first to follow up on this finding, announcing the discovery of the star’s second gas giant planet in 2001.
The Kepler mission, due to launch in June 2008, will search for terrestrial planets orbiting distant stars. The mission defines an Earth-size planet as being between 0.5 and 2.0 Earth masses, or between 0.8 and 1.3 Earth’s diameter. Planets between 2 and 10 Earth masses, such as the planet announced on Monday, are defined as Large Terrestrial planets.
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To ensure that, by 2015, all children have access to and complete primary education that is free, compulsory and of good quality
Achieve universal primary education
Universal education will speed progress towards all development goals
Almost all of the Millennium Development Goals (MDGs) are interdependent, but achieving two of them – universal education (MDG 2) and gender equality and empowering women (MDG 3) – is vital to meeting all the others.
Educating children helps reduce poverty. Education will give the next generation the tools to fight poverty and conquer disease. School also offers children a safe environment, with support, supervision and socialization. Here they learn life skills that can help them prevent diseases, including how to avoid HIV/AIDS and malaria. Children may receive life-saving vaccines, fresh water and nutrient supplementation at school.
Many countries are close to universal coverage
Universal education may seem a relatively straightforward goal, but it has proved as difficult as any to achieve. Decades after commitments and reaffirmations of those commitments were made in order to provide a quality education for every child, some 67 million primary-school-age children are still denied this right, according to the United Nations Educational, Scientific and Cultural Organization (UNESCO Institute for Statistics, Global Education Digest 2011).
Many countries have committed themselves to more than the achievement of universal primary education. Their expanded goals include several years of secondary schooling and a new universal basic education. The challenge of keeping children in school after primary school is great. UNESCO reports that when lower secondary-school-age children are counted in, the number of out-of-school children is doubled, as more than 72 million adolescents in this group are out of school.
The barriers to school attendance at secondary level resemble those at primary level, but those barriers are intensified. The cost of secondary schooling is often higher than the cost of primary schooling and therefore more difficult for families to afford; secondary schools are further from home, often requiring transportation; and the conflict between educational aspirations and the potential income that could be earned by a working adolescent becomes greater.
|Millennium Development Goal|
|To promote gender equality and empower women. Target: Eliminate gender disparity in primary and secondary education, preferably by 2005, and in all levels of education no later than 2015|
Educating girls provides benefits through generations
UNICEF advocates high-quality basic education for all, with an emphasis on gender equality and eliminating disparities of all kinds. In particular, getting girls into school and ensuring that they stay there has what UNICEF calls a "multiplier effect."
Educating a girl dramatically reduces the chance that her child will die before age five. Furthermore, educated girls are likely to marry later and have fewer children, who in turn will be more likely to survive and be better nourished and educated. Educated girls are more productive at home and better paid in the workplace, and more able to participate in social, economic and political decision-making.
Of the 67 million out-of-school primary-school-age children, 53 per cent are girls. Of the lower secondary out-of-school adolescents, 52 per cent are girls.
UNESCO Institute for Statistics (UIS), Global Education Digest 2011: Comparing Education Statistics Across the World, UIS, Montreal, 2011. |
Researchers at a Dutch university have devised a method of ‘substantially improving’ the production of relatively inexpensive dye-sensitised solar cells. Long touted as a cheap alternative to high-cost silicon solar cells, dye-sensitised cells imitate the natural conversion of sunlight into energy by plants and light-sensitive bacteria.
Annemarie Huijser, from the Delft University of Technology, noted that plants are able to transport absorbed solar energy over long distances, typically about 15-20 nanometres, to a location in which it is converted into chemical energy. This is because the chlorophyll molecules in leaves are arranged in the best possible sequence.Huijser attempted a partial recreation in solar cells of this process as found in plants. She focused on what are known as dye-sensitised cells comprising a semiconductor, such as titanium dioxide, covered with a layer of dye.
The dye absorbs energy from sunlight, which creates excitons. These energy parcels then need to move towards to the semiconductor. Once there, they generate electric power. “You can compare dye molecules to Lego bricks. I vary the way the bricks are stacked and observe how this influences the exciton transport through the solar cells,” explained Huijser.”Excitons need to move as freely as possible through the solar cells in order to generate electricity efficiently.” |
Make is a tool which controls the generation of executables and other non-source files of a program from the program's source files.
Make gets its knowledge of how to build your program from a file called the makefile, which lists each of the non-source files and how to compute it from other files. When you write a program, you should write a makefile for it, so that it is possible to use Make to build and install the program.
Capabilities of Make
- Make enables the end user to build and install your package without knowing the details of how that is done -- because these details are recorded in the makefile that you supply.
- Make figures out automatically which files it needs to update,
based on which source files have changed. It also automatically
determines the proper order for updating files, in case one non-source
file depends on another non-source file.
As a result, if you change a few source files and then run Make, it does not need to recompile all of your program. It updates only those non-source files that depend directly or indirectly on the source files that you changed.
- Make is not limited to any particular language. For each
non-source file in the program, the makefile specifies the shell
commands to compute it. These shell commands can run a compiler to
produce an object file, the linker to produce an executable,
arto update a library, or TeX or Makeinfo to format documentation.
- Make is not limited to building a package. You can also use Make to control installing or deinstalling a package, generate tags tables for it, or anything else you want to do often enough to make it worth while writing down how to do it.
Make Rules and Targets
A rule in the makefile tells Make how to execute a series of commands in order to build a target file from source files. It also specifies a list of dependencies of the target file. This list should include all files (whether source files or other targets) which are used as inputs to the commands in the rule.
Here is what a simple rule looks like:
target: dependencies ... commands ...
When you run Make, you can specify particular targets to update; otherwise, Make updates the first target listed in the makefile. Of course, any other target files needed as input for generating these targets must be updated first.
Make uses the makefile to figure out which target files ought to be brought up to date, and then determines which of them actually need to be updated. If a target file is newer than all of its dependencies, then it is already up to date, and it does not need to be regenerated. The other target files do need to be updated, but in the right order: each target file must be regenerated before it is used in regenerating other targets.
Advantages of GNU Make
GNU Make has many powerful features for use in makefiles, beyond what other Make versions have. It can also regenerate, use, and then delete intermediate files which need not be saved.
GNU Make also has a few simple features that are very convenient. For
-o file option which says ``pretend that
source file file has not changed, even though it has changed.''
This is extremely useful when you add a new macro to a header file.
Most versions of Make will assume they must therefore recompile all the
source files that use the header file; but GNU Make gives you a way to
avoid the recompilation, in the case where you know your change to the
header file does not require it.
However, the most important difference between GNU Make and most versions of Make is that GNU Make is free software.
Makefiles And Conventions
We have developed conventions for how to write Makefiles, which all GNU packages ought to follow. It is a good idea to follow these conventions in your program even if you don't intend it to be GNU software, so that users will be able to build your package just like many other packages, and will not need to learn anything special before doing so.
Downloading GNU Make
GNU Make can be found on the main GNU ftp server: http://ftp.gnu.org/gnu/make/ (via HTTP) and ftp://ftp.gnu.org/gnu/make/ (via FTP). It can also be found on the GNU mirrors; please use a mirror if possible.
Documentation for Make is available online, as is documentation for most GNU software. You may also find more information about Make by running info make or man make, or by looking at /usr/doc/make/, /usr/local/doc/make/, or similar directories on your system. A brief summary is available by running make --help.
The main discussion list is <email@example.com>, and is used to discuss most aspects of Make, including development and enhancement requests, as well as bug reports.
There is a separate list for general user help and discussion, <firstname.lastname@example.org>.
GNU Make has been ported to a great many systems. One that poses unique challenges is Microsoft DOS and Windows platforms; because of that there is a GNU Make mailing list dedicated specifically to users of those platforms: <email@example.com>.
Announcements about Make and most other GNU software are made on <firstname.lastname@example.org>.
To subscribe to these or any GNU mailing lists, please send an empty mail with a Subject: header of just subscribe to the relevant -request list. For example, to subscribe yourself to the GNU announcement list, you would send mail to <email@example.com>. Or you can use the mailing list web interface.
Development of Make, and GNU in general, is a volunteer effort, and you can contribute. For information, please read How to help GNU. If you'd like to get involved, it's a good idea to join the discussion mailing list (see above).
- Test releases
- Trying the latest test release (when available) is always appreciated. Test releases of Make can be found at http://alpha.gnu.org/gnu/make/ (via HTTP) and ftp://alpha.gnu.org/gnu/make/ (via FTP).
- For development sources, bug and patch trackers, and other information, please see the Make project page at savannah.gnu.org.
- Translating Make
- To translate Make's messages into other languages, please see the Translation Project page for Make. If you have a new translation of the message strings, or updates to the existing strings, please have the changes made in this repository. Only translations from this site will be incorporated into Make. For more information, see the Translation Project.
- GNU Make was written by Richard Stallman and Roland McGrath. It has been maintained and updated by Paul Smith since version 3.76 (1997). Please use the mailing lists for contact.
Make is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. |
Rise and Fall
Regardless of the obscurity of their origins, it is clear that a distinctive Etruscan culture evolved about the 8th cent. B.C., developed rapidly during the 7th cent., achieved its peak of power and wealth during the 6th cent., and declined during the 5th and 4th cent. Etruria had no centralized government, but rather comprised a loose confederation of city-states. Important centers were Clusium (modern Chiusi), Tarquinii (modern Tarquinia), Caere (modern Cerveteri), Veii (modern Veio), Volterra, Vetulonia, Perusia (modern Perugia), and Volsinii (modern Orvieto).
The political domination of the Etruscans was at its height c.500 B.C., a time in which they had consolidated the Umbrian cities and had occupied a large part of Latium. During this period the Etruscans were a great maritime power and established colonies on Corsica, Elba, Sardinia, the Balearic Islands, and on the coast of Spain. In the late 6th cent. a mutual agreement between Etruria and Carthage, with whom Etruria had allied itself against the Greeks c.535 B.C., restricted Etruscan trade, and by the late 5th cent. their sea power had come to an end.
The Romans, whose culture had been greatly influenced by the Etruscans (the Tarquin rulers of Rome were Etruscans), were distrustful of Etruscan power. The Etruscans had occuped Rome itself from c.616 B.C., but in c.510 B.C. they were driven out by the Romans. In the early 4th cent., after Etruria had been weakened by Gallic invasions, the Romans attempted to beat the Etruscans back. Beginning with Veii (c.396 B.C.) one Etruscan city after another fell to the Romans, and civil war further weakened Etruscan power. In the wars of the 3d cent., in which Rome defeated Carthage, the Etruscans provided support against their former allies. During the Social War (90–88 B.C.) of Sulla and Marius the remaining Etruscan families allied themselves with Marius, and in 88 B.C. Sulla eradicated the last traces of Etruscan independence.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved. |
Today, let's see what mathematics can tell us about language. The University of Houston Mathematics Department presents this program about the machines that make our civilization run, and the people whose ingenuity created them.
In the novel The Count of Monte Cristo, one of the most memorable characters is Monsieur Noirtier de Villefort. He is completely paralyzed and mute, and yet is able to communicate by blinking his eyes. The system he uses is slow and laborious, and involves running through columns and columns of words in a dictionary. When I first read the novel, I wandered how this could be done more efficiently? Could people capable of only minimal movement communicate with the same speed as you and me? To achieve this, we need a good understanding of the structure of language.
But how can we describe the structure of something so vast and complex as language itself? After all, our languages are sufficiently flexible to capture nearly all of our thoughts and feelings. However, they do obey very precise mathematical rules.
For instance, in the 1930s the American linguist George Kingsley Zipf observed that the length of a word is precisely related to the frequentcy of its use. We use long words infrequently — our sentences are formed mostly by words containing only a few letters. Zipf argued that this is part of a larger "Principle of Least Effort".
If we wish to talk with a paralyzed communicant we should use a list of words that arranged according to the frequency of their use. Such a list would start with short words and contain words of increasing length. Using a regular dictionary is terribly inefficient.
But to do better, we need a deeper understanding of language structure. Words in a sentence are not independent of one another. Likewise, letters do not follow one another at random. For instance, "E" is the most frequent letter in the English language. However, if you see the letter "T" it is more likely to be followed by the letter "H" than by "E" — despite the higher overall frequency of the letter "E". But if we see the letter "T" followed by "H," most of us will guess that the next letter will be "E" — the English language is full of words that start with the arrangement "T. H. E....".
And this structure can be used to minimize the effort of writing: For instance the program Dasher allows you to enter text without using your hands. You can direct a pointer to the first letter in a word using an eye-tracking device. After you've entered the first letter, the program anticipates the most likely letters to follow and displays them more prominently than the others. By shifting your gaze you can then point to the next letter in the word. As letters zoom by on the screen the program seems to anticipate what you mean to say, prominently displaying the most likely sequences of letters. After some practice, you can enter 25 or more words per minute.
Writing, speech and literature seem to be far removed from mathematics. However, mathematics is much more than the study of numbers. It is the study of structures and forms wherever they may appear. And is there anything that humankind has created that has a structure richer and more complex than our language?
This is Krešimir Josić at the University of Houston where we are interested in the way inventive minds work.
Jean-Dominique Bauby suffered a massive stroke that left him completely paralyzed (locked in). He dedicated his memoir, The Diving Bell and the Butterfly, by blinking his left eye.
A readable, but somewhat technical discussion of different probability distribution, including the distribution that governs then frequency of words, is given here http://arxiv.org/pdf/cond-mat/0412004. |
Common Core Standards:
(RF.1.4)-Read with Sufficient accuracy and fluency to support comprehension.
(RF.1.4a)-Read on-level text with purpose and understanding.
(RF.1.4b)-Read on-level text orally with accuracy, appropriate rate, and expression on successive readings.
(RF.1.4c)-Use context to confirm or self-correct word recognition and understanding, rereading as necessary.
This quarter we are working on Reading Fluency, which is the ability to read a text accurately and quickly. When fluent readers read silently, they recognize words automatically. They group words quickly to help them gain meaning from what they read. Fluent readers read aloud with little effort and with expression. Their reading sounds natural, as if they are speaking. Readers who have not yet developed fluency read slowly, word by word. Their oral reading is choppy.
Fluency is important because it provides a bridge between word recognition and comprehension. Because fluent readers do not have to concentrate on decoding (sounding out) the words, they can focus their attention on what the text means. They can make connections with the ideas in the text and their background knowledge. In other words, fluent readers recognize words and comprehend at the same time. However, less fluent readers must focus their attention on figuring out the words, which leaves little attention for understanding the text.
Ways you can help your child become a fluent reader (that you may already do):
Model fluent reading of their favorite book or book from school.
Have your child repeatedly read short stories or passages while you offer help-read 3-4 times
CD -assisted reading helps students read along in their books as they hear a fluent reader read the book on CD |
Corals around the world, already threatened by pollution, destructive fishing practices and other problems, are also widely regarded as among the ecosystems likely to be first — and most — threatened with destruction as earth’s climate warms.
But there is reason to hope, researchers are reporting. The scientists, from Penn State University and elsewhere, have produced new evidence that some algae that live in partnership with corals are resilient to higher ocean temperatures. One species, Symbiodinium trenchi, is particularly abundant – “a generalist organism,” the researchers call it, able to live with a variety of coral hosts.
Corals and algae live together in what scientists call a symbiotic relationship. Coral polyps shelter the algae and as the tiny plants photosynthesize they produce sugars the corals rely on for food. When water warms, though, reefs’ brown or green algae partners die, leaving the reefs white. These so-called bleaching events have become more common as ocean waters warm.
The new research focused on corals in the Andaman Sea, in the northeastern Indian Ocean, but other scientists have made similar algae findings in the Caribbean Sea and the Pacific Ocean.
Heat-resistant algae are not enough to save corals, most researchers agree, but their presence may buy time for some reefs. Other researchers have suggested that unusual periods of warm water may allow heat-resilient algae to proliferate, to the long term benefit of corals.
Unfortunately, though, heat-resilient algae do not necessarily occur in corals everywhere. And it is not clear whether importing the algae to threatened reefs would work to save them. “You never know what the effects might be of introducing an organism into an ecosystem in which it is not well established,” Todd LaJeunesse, one of the Penn State researchers said in a statement reporting the new work.
Also, while the algae findings offer a glimmer of hope, there remain plenty of reasons to worry. Perhaps chief among them is the fact that as ocean waters absorb carbon dioxide they become more acidic, threatening the coral skeletons. |
The Online Teacher Resource
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Grade 6 through Grade 8 (Middle School)
Overview and Purpose:
The students will explore and create a poster design using polygons. The posters will be displayed in the classroom and students will be challenged to name as many of them as they can. This activity will allow students a tactile, expressive way to learn about polygons.
The student will be able to create a poster comprised of at least four different polygons.
One piece or half piece of poster board for each pair of students
Various colors and types of paper
Glue and/or tape
White board and markers
Pictures of various polygons
Write the definition of a polygon on the board (a plane shape with straight sides) and show the students some examples of polygons.
Explain to the students that they are going to work in pairs to create a poster with at least four different polygons. Show them the supplies and encourage them to be creative. Give them one or two days to complete the posters depending on how involved they are.
Display the posters on the wall and discuss the different polygons. Have students research and label all the polygons with their correct names.
This hands-on activity will allow for a variety of learning styles. Taking time to have students create their own polygons will help them learn the concept much better than if they just read about it in their textbook. The lesson could be extended to include a homework paper that asked students to draw and label polygons with x amount of sides. |
James Madison (1751-1836) was the principal architect of the United States Constitution and the fourth president of the United States. During the Revolution, he helped draft Virginia's state constitution and served in the Continental Congress. In the years immediately following the war, he grew convinced that domestic and international disasters would follow unless the national government was reformed, and therefore joined those calling for a constitutional convention. He teamed with Alexander Hamilton and John Jay to publish the Federalist Papers.
Madison's Notes of Debates in the Federal Convention of 1787 provided the chief source of information about the debates and compromise processes of the Convention, which was closed to the public. Along with Hamilton and Jay, Madison composed the series of 85 anonymously published essays known as The Federalist Papers in order to encourage support for the Constitution and press the argument for its ratification. Though Madison initially believed that the oft-proposed Bill of Rights would be an unnecessary precaution against the excesses of federal power under the new Constitution, he changed his mind by autumn 1788 and became the principal force behind the rapid passage of the first ten amendments in Congress. |
The earth is performing an enormous disposal service for the human race. About half of the carbon we are dumping into the atmosphere does not stay there and is instead taken up by the oceans and land. Were this not the case, scientists say, the earth would probably be warming far more rapidly.
One of the biggest questions in climate science is: How long will that disposal service last?
Remarkably, the earth’s ability to keep socking away carbon has for decades kept up with human activity, with the proportion that disappears from the atmosphere remaining close to 50 percent even as our emissions soared. Computer analyses of the climate have long predicted that the uptake would become less efficient sometime in this century. If that happened, the level of carbon dioxide in the air would begin rising faster, trapping more of the sun’s heat.
Two new scientific papers shed some light on this issue. One of them is reassuring, at least in the short run, while the other offers new reasons to worry about the long-term stability of the “carbon sink,” as scientists call it.
The good news first: A new paper suggests that the earth’s ability to take up carbon has not yet begun to weaken.
The study, published online Wednesday by the journal Nature and led by Ashley Ballantyne of the University of Colorado, Boulder, is the latest installment in a debate that has been going on for several years.
Some research, focused on regional carbon sinks on land (such as forests) or in the ocean, had suggested the beginnings of a decline. Earlier this week, for instance, this paper found a decline in the sink in the Western forests of North America as a result of a drought from 2000 to 2004. These regional findings led some scientists to suggest that the carbon sink might be weakening on a global scale, but that claim was countered by papers that found no significant drop.
The new paper is an attempt at a definitive take on this question. Basically it is a meticulous statistical analysis of global carbon dioxide measurements that have been going on for decades, including the renowned monitoring effort on the slopes of the Mauna Loa volcano in Hawaii. Taking rigorous account of all possible sources of error, Dr. Ballantyne and his colleagues found no convincing evidence that the global carbon sink was weakening.
They warned, however, that this finding should not lead to complacency about the risks of unchecked carbon dioxide emissions. “It’s not a question of whether or not natural sinks will slow their uptake of carbon, but when,” Caroline B. Alden, a doctoral student at the University of Colorado and co-author of the paper, was quoted as saying in a news release.
Still, assuming the paper holds up to critical scrutiny, it is unquestionably good news that the shift has not yet occurred.
A second paper, published earlier in the week by the journal Nature Geoscience, provides insight into how the disposal service in the ocean is actually working. The surprising finding is that a handful of relatively concentrated spots in the Southern Ocean account for a high proportion, roughly 20 percent, of the entire oceanic carbon uptake.
The reason is that while carbon dioxide can easily dissolve out of the air into ocean water, it tends to stay in a surface layer that does not mix well with the colder, denser water below. It can even escape that surface layer to re-enter the atmosphere. The scientists found that certain combinations of winds and currents are required to overcome the barrier and pump carbon dioxide into the deep ocean, where much of it stays locked away for thousands of years.
The paper, led by Jean-Baptiste Sallée of the British Antarctic Survey, found “hot spots” in the Southern Ocean where this process is operating most efficiently. The two most important are in the Drake Passage, between Antarctica and South America, and in a region of the ocean due south of western Australia. The scientists used measurements from the new Argo network of floating robots to make the most complete analysis yet of the role of currents.
The obvious concern the paper raises is that climate change could disturb the existing pattern of winds and currents and shut down the hot spots, making the entire ocean less efficient as an absorber of carbon dioxide.
In principle, of course, things could go the other way too, with climate change perhaps creating more such hot spots and increasing the efficiency of the disposal service. But we know from the geological record that past jumps in the earth’s temperature have tended to raise the amount of carbon dioxide in the air, which then reinforced the warming trend. So that’s a pretty good reason to think that things will unfold the same way as a result of human-caused warming.
“The good news is that today, nature is helping us out,” said James W. C. White, a University of Colorado researcher and a co-author on the Nature paper, in a news release. “The bad news is that none of us think nature is going to keep helping us out indefinitely.”
An earlier version of this post misattributed the quotation “It’s not a question of whether or not natural sinks will slow their uptake of carbon, but when.” A news release attributed it to Caroline B. Alden, a doctoral student at the University of Colorado and co-author of the paper, not Ashley Ballantyne, a professor at the University of Colorado and the study’s lead author. |
Classification of the Chemical Elements
Return to Chemistry Index
Purham, James Chicago Vocational High School
1. The students will learn how the chemical elements are arranged on
the PERIODIC TABLE.
2. Given adequate information, students will be able to arrange the
elements on the PERIODIC TABLE.
3. Students will learn about some of the important chemical and
physical properties of the elements.
One board that is approximately one meter square for every five
students, piece of felt material that is large enough to cover each
board, felt material of several different colors to be used as
elements, stick pins to anchor felt strips to board, lineless white
paper and stapler.
1. Cover each board with a piece of felt material. One board per five
students is suggested.
2. Draw an outline of PERIODIC TABLE on felt material that is attached
to each board.
3. Cut several strips of felt material of different colors. Individual
strips of felt material should be small enough to fit into the boxes
on the PERIODIC TABLE.
4. Cut strips of lineless paper about the same size as the felt strip.
5. On strips of paper, write enough description of the elements so that
students can locate the positions of the elements on the PERIODIC
6. Strips should also be cut for first exercise using the chart. Do
not attach anything to these felt strips. NOTE: FELT STRIPS OF THE
SAME COLOR SHOULD BE MADE FOR ALL ELEMENTS THAT ARE IN THE SAME
1. Give a brief introduction to the PERIODIC TABLE, such as the
importance and some of the problems that were encountered in
arranging the elements in a scientific manner.
2. Introduce the terms FAMILY, GROUP, PERIOD and SERIES.
3. Distribute PERIODIC TABLES and several strips of different colors
that have nothing attached to them. Ask students to arrange felt
strips in what they consider to be an orderly manner. Allow about
five minutes for this exercise. Each group will probably have the
strips arranged in a different way. The purpose of having the
students to arrange the strips, is to dramatize some of the
problems that were experienced in agreeing on a way to arrange the
elements on the table.
4. Discuss the following: triad system, octave system, Mendeleev's
periodic table, variation of metallic and nonmetallic properties of
the elements in a family and a period; variation of the size of the
elements in a family and a period; variation of electron affinity of
the elements in a family and a period; variation of the ionization
of the elements in a family and a period; and variation of
electronegativity in a family and a period.
5. Pass out elements (felt strips) on which descriptions have been
attached and instruct the students to arrange them on the chart,
based on the information that was given during the lecture.
6. After adequate time has been given for students to place elements on
the table, ask students to describe the most unique things they
noticed about the table. |
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are, which is of great importance for the appearance at the image plane. If an aperture is narrow, then highly collimated rays are admitted, resulting in a sharp focus at the image plane. If an aperture is wide, then uncollimated rays are admitted, resulting in a sharp focus only for rays with a certain focal length. This means that a wide aperture results in an image that is sharp around what the lens is focusing on and blurred otherwise. The aperture also determines how many of the incoming rays are actually admitted and thus how much light reaches the image plane (the narrower the aperture, the darker the image for a given exposure time).
An optical system typically has many openings, or structures that limit the ray bundles (ray bundles are also known as pencils of light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that determines the ray cone angle, or equivalently the brightness, at an image point. |
This tally shows that Jackson received a plurality of 99 electoral votes, falling 32 votes shy of the majority required by the Constitution. Since no candidate received a majority of the electoral votes, the House retired to its chamber to select a President.
House Speaker Henry Clay, who finished fourth and was no longer a candidate, was in a critical position to determine the outcome of the House vote. He threw his support and considerable influence behind John Quincy Adams. Although the Constitution does not require that the House select the lead candidate, when John Quincy Adams was chosen over Andrew Jackson, Jackson and his supporters charged that the House of Representatives had openly defied the will of the people.
Tally of electoral votes, showing the number of votes received by the four candidates: Andrew Jackson, John Quincy Adams, William H. Crawford, and Henry Clay, February 9, 1825
National Archives, Records of the U.S. House of Representatives, exhibited with the permission of the House of Representatives.
Next section: Civil War and Reconstruction (1850-1877)
Previous part of this section: Lewis and Clark Expedition
Expansion and Reform (1801-1861)
American Originals 2 |
The success of wind power is usually measured by the growth in installed capacity. This capacity, however, is peak power: the maximum power at optimum wind speed. The average output of a wind turbine is always lower.
The capacity factor of a wind turbine expresses the ratio of average power output to peak power. Many national and European targets assume a capacity factor of around 30%, while the world’s average capacity factor in 2005 was only 19.6%.
The capacity factor of a wind turbine is determined by:
1) Operation at less than maximum output. Most wind turbines have their maximum output power at wind speeds between 12-15 m/s and 25 m/s. Below that range, the power output decreases by the third power of the wind velocity. In other words, at half the optimal wind speed (7.5 m/s), power output is only one eighth of peak power.
2) Shut down due to excessive or inadequate wind velocity. In general, wind turbines shut down when wind speeds drop below 3-4 m/s or rise above 25 m/s.
3) Other shut downs. These may occur due to scheduled maintenance, equipment failure, or for safety reasons during a grid incident. These same events also determine the capacity factor of conventional fossil fuel power plants, which varies roughly between 50% and 90%.
The average capacity factor differs significantly between countries. Countries with well exploited wind resources tend to have a lower capacity factor. Germany, for instance, has a capacity factor of only 16.9%. That is because the best sites get developed first, and subsequent development goes onto sites with poorer wind characteristics, thus reducing the average capacity factor. The U.S. have a large installed capacity, but a high capacity factor (28.8%), meaning that it still has a large wind development potential left to exploit.
Given this perspective, the target of the European Wind Association seems rather unrealistic. It aims to reach the figure of 180 GW installed capacity in Europe with an average capacity factor of 31.7% by 2010. It is argued that a large part of the growth in the European wind sector in the next two years will be achieved by off-shore wind parks, which are believed to have higher capacity factors. However, figures from the UK from 2005 indicate that this is not necessarily true. The UK on-shore wind park (1,651 MW) has an average capacity factor of 27.4% and the off-shore wind park (304 MW) a capacity factor of 27.2%. Wind characteristics tend to be better for off-shore turbines, but off-shore wind turbines also require more maintenance. This could explain why the UK capacity factor turns out to be similar than that of the on-shore turbines. |
The Best Season (Grades K-1)
In this lesson, students will develop and use vocabulary for different types of weather; students will also gain an understanding of how the seasons change.
•Use descriptive words to convey basic ideas
•Use visual structures and functions of art to communicate ideas
•Learn that short-term weather conditions can change daily, and weather patterns change over seasons
The Best Season Student Printable (PDF)
Low Odor Dry Erase Markers
Art Supplies such as markers, glitter, and paint
Background Discussion (10 minutes)
1. Discuss how the weather changes as the seasons change. Describe the seasons in your region. Activate prior knowledge by asking students to describe their favorite activities in each season. Tell students that the seasons are different in different parts of the world. For example, the Southeast part of United States is warmer during the whole year than the Northeast United States. In the Southeast, leaves on many of the trees do not change colors in the fall. Places in the Southern Hemisphere have winter weather during the months that there is summer weather in the Northern Hemisphere. In tropical areas, near the equator, there are only two seasons: the rainy season and the dry season. Direct students’ attention to the classroom poster.
Using the Student Printable (25 minutes)
2. Draw a 4-column chart on the whiteboard titled: Sensational Seasons. Label each of the columns with one season: Summer, Fall, Winter, Spring.
3. Distribute copies of The Best Season Student Reproducible (PDF) . Review the words in the Word Bank together. As a class, decide which word belongs with each season and add it to the correct column on the chart. Use different colored markers for each season to separate them visually.
Sensational Seasons Chart:
SUMMER - Humid ♦ FALL - Crisp ♦ WINTER - Freezing/Snowy ♦ SPRING - Drizzle
4. Ask students to add their favorite season-appropriate words to the chart.
5. Read the story on the reproducible aloud. As a class, choose words from the chart to fill in the blanks.
6. Ask students to write one sentence about their favorite season on the reproducible.
Colorful Extension Activity (25 minutes)
7. Create a simple bulletin board in the shape of a tree trunk and branches using bulletin board paper. Have students add season-appropriate vocabulary words and decorations to the tree as the seasons change. Here are some ideas: Winter—snowflakes, Spring—birds, raindrops, or flowers, Summer—green leaves, Fall—colored leaves or apples. Encourage students to use the words in their own writing throughout the year.
freezing, snowy, drizzle, humid, crisp |
is not a new phenomenon, nor is extinction. Many times in Earths history,
the climate has changed sometimes rapidly and drastically and
species have become extinct. At least five times, more than 50 percent of species
inhabiting the planet have died out, and as few as 2 to 4 percent of the species
that have ever lived are believed to survive today. Some scientists say that
in the face of impending climate change, the world may be headed into another
mass extinction event.
As temperatures warm, the American pika, which lives on moist, cool mountaintops, such as Mount Evans in Colorado, shown here, does not have much room for upslope migration. Courtesy of Steven Morello.
The difference today is that the world is inhabited by close to 7 billion people and biodiversity has been put into small refuges rather like islands, said Richard Leakey, one of the worlds foremost anthropologists and wildlife ecologists, at the Stony Brook World Environmental Forum, which he convened last May on Long Island to discuss climate change and biodiversity. Scientists, he said, need to be talking now about what climate change is going to do to life as we have known it. Developing a better understanding of climates effects on various species, as well as better protecting and connecting the existing refuges, will help better prepare the world for any changes to come, meeting participants said.
In its Third Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) estimated that Earth will warm by between 1.4 and 5.8 degrees Celsius by 2100. While humans may be able to adapt to warming at the low end of this range, other life forms might face more serious consequences; warming at the high end of the range could be catastrophic for all life on the planet, considering 5 to 7 degrees Celsius is the difference between an ice age and an interglacial period, says Stephen Schneider, a climatologist at Stanford University who has served on the IPCC.
Still, the climate change debate is characterized by deep uncertainty, Schneider says, noting that there will always be uncertainty about future events. Still, he says, if the IPCC projections are correct even on the lower end of the range, likely effects could include more frequent heat waves and less frequent cold spells; increased weather extremes, including drought and storms; loss of farming productivity; and rising sea levels and sea-surface temperatures. No place will be immune, he says, including areas set aside as protected habitats.
More than 1.9 million species have been cataloged on Earth, but scientists believe that at least 5 million to 30 million species exist, according to the World Conservation Union (IUCN). Over the past 500 years, human activity has forced 844 known species to extinction, and 15,589 known species are facing extinction right now. The current extinction rate, since A.D. 1500, is estimated to exceed the natural extinction rate by 100 to 1,000 times, IUCN says. And climate change will only exacerbate this rate as further stress is put on an already stressed system, says Lee Hannah, a climate change biologist at the Center for Applied Biodiversity Science with Conservation International.
But just as climate change will not affect the whole world equally, it will not affect all species in the same way, Hannah says. The fossil record clearly shows, he says, that species respond individually to climate change, not as coherent communities. So although scientists are already seeing some of the changes to come, especially in higher latitudes, such as birds migrating and breeding earlier in spring, and fish moving to cooler waters farther north, it is important to conduct bioclimatic modeling studies to give us a better picture of what could happen, Hannah says.
Three hundred species of these exotic plants called proteas, which are endemic to the Cape Floristic Region of South Africa, stand a 21 to 40 percent chance of extinction if the climate warms as projected in mid-range estimates by the Intergovernmental Panel on Climate Change, according to new research in BioScience. Courtesy of Guy Midgley.
Not only warming temperatures pose problems, says Thure Cerling, a geologist at the University of Utah in Salt Lake City. The water balance will also change, causing trouble for species that depend on certain equilibriums of precipitation and evaporation. For example, the American pika, which depends on moist, cool mountaintop climates, is quickly facing extinction due to climate change. Because the small rodent-like mammals already live in tiny niches atop mountains, they do not have much room to move up-slope and they are not physiologically designed to migrate, according to the World Wildlife Fund (WWF). Although some species can migrate, such as the grizzly bear, species that depend on cooler temperatures, such as those that live in higher latitudes or altitudes such as pikas or polar bears, will be even more threatened because of less room for habitat expansion, Hannah says.
Climate change impacts are equally dramatic in the oceans, says Jane Lubchenco, a marine ecologist at Oregon State University in Corvallis. Were already seeing increased sea-surface temperatures, upwelling, more storms, increased acidification and circulation changes, she says. Although scientists do not know enough yet about all the effects of these changes on marine organisms, Lubchenco says, they do know that corals, which cannot migrate, are bleaching and dying quickly, and fish that can migrate, such as tuna, are moving to cooler waters.
Climate change is a reality that at this point cannot be turned around, Hannah says. But we dont have to throw up our hands into the air in exasperation, Cerling adds. We dont have to lose the rest of the megafauna we have on the planet. But we do have to do something now to protect it if we dont want to lose it.
A key step in that process is resilience building, says Lara Hansen, chief scientist of the Climate Change Program at WWF. Resilience building changes the way protected areas and resources are managed by considering not only what the ecosystems or habitats (and everything in the ecosystems) need right now, but also what they might need 20, 50 or 100 years from now. Part of what ecosystems need is more connectivity between protected areas a way to change what are now postage-stamp-sized refuges surrounded by human activities to interconnected systems that give plants and animals more room in which to operate, she says.
About 12 percent of Earths land surface is protected, says Jeff McNeely, chief scientist at IUCN, while less than 1 percent of the ocean is protected, Lubchenco says. Merely setting aside land or ocean acreage, however, is insufficient, Lubchenco says its hugely important to pay attention to whats happening around the reserve as well as whats happening inside.
As the climate changes, for example, threatened species may need to change locations to survive, McNeely says. Having spaces between and surrounding protected areas managed in ways that do not discourage species from spreading out would then become key, he says. Even better, would be to manage these in ways that actively encourage dispersal, for example, by creating national forests and building wildlife underpasses or corridors where highways cut through the habitat, such as has been done in the Los Angeles area, he says.
Protected areas are great, but they wont [preserve biodiversity] alone, Hansen says. Countries also need to take active steps to reduce greenhouse gas emissions to curtail global warming, she says. Indeed, Hannah says, we need to stop anything that is currently threatening ecosystems because climate change will only heighten the threats. It is important to emphasize that extinctions estimated due to climate change are not inevitable, he says, but if we cant do the simple stuff like protecting parks now, we have little hope of addressing a complex threat like climate change later.
Climate Change Program at World Wildlife Fund
World Conservation Union (IUCN)
Stephen Schneider's Web site
Jane Lubchenco's Web site
Stony Brook World Environmental Forum
Center for Applied Biodiversity Science at Conservation International
Convention on Biological Diversity
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MacGregor Campbell, consultant
Just because you're small doesn't mean you can't be strong. These micro-robots are half a millimeter wide but they can push around objects four times their own weight (see video above).
To create the plucky bots, Igor Aronson of the Argonne National Laboratory in Illinois suspended tiny magnetic particles between two layers of fluid that don't mix. When an alternating magnetic field was applied perpendicular to the boundary of the liquids, he found that the particles self-assembled to create tiny, worm-like robots. They could be moved around by applying a second, smaller magnetic field parallel to the plane.
Aronson and his team were able to manipulate the magnetic fields to make the robots behave like a pair of tweezers. As seen in this video, they can grasp and transport a glass bead almost four times their weight.
The team also found that the bots come in two types, which is determined by the direction they move in a magnetic field. By coaxing two opposing pairs to assemble, a square shape that can trap smaller particles is formed. The device exerts more force than a laser and could lead to new micro-manufacturing techniques.
For more tiny robots in action, check out this swimming microbot. |
Word Study Program: Prefix Word Building Game
- Grades: 3–5
This word study game is created by attaching both of the game board files (see links below) to create a 2x2 game board. In this game, students build new words using prefixes and root words. The recording sheet also emphasizes vocabulary development as students must use the words they make in a sentence to show that they understand how a prefix changes the meaning of a word.
To play, you will need to create a prefix spinner with the prefixes mis-, pre-, re-, un-, dis-, and de- to play the game. This game can be altered and used for suffixes as well. (You would just need to change the root words and create a suffix spinner.) |
Naval Research Laboratory (NRL) scientists are leading a multi-agency study which reveals that a very high-resolution Doppler radar has the unique capacity to detect individual cloud hydrometeors in the free atmosphere.
This study will improve scientists’ understanding of the dynamics and structure of cloud systems.
This Doppler radar was previously used to track small debris shed from the NASA space shuttle missions during launch. Similar to the traces left behind on film by sub-atomic particles, researchers observed larger cloud particles leaving well-defined, nearly linear, radar reflectivity “streaks” which could be analyzed to infer their underlying properties.
Scientists could detect the individual particles because of a combination of the radar’s 3MW power, narrow 0.22 degree beamwidth, and an unprecedented range resolution as fine as 0.5m. This combination of radar attributes allows researchers to sample a volume of cloud about the size of a small bus (roughly 14 m3) when operating at a range of 2 km.
With such small pulse volumes, it becomes possible to measure the properties of individual raindrops greater than 0.5mm in diameter due to the low concentration of such drops in naturally occurring cloud systems and the overwhelming dominance such drops have on the measured radar reflectivity when present in a field comprised of smaller particles. |
Juneteenth holiday exhibit on display in Adams Library
An exhibit about the history of the Juneteenth holiday is on display in the Adams Library lobby through the month of June.
Juneteenth, or Emancipation Day, commemorates June 19, 1865, the date that a Union ship sailed into Galveston, Texas, and the city was informed that the Civil War had ended and that all slaves in Texas were free.
Celebrations of June 19, or “Juneteenth,” began in Texas in 1866 and spread to the neighboring states of Louisiana, Arkansas and Oklahoma, and to other states as African-American Texans migrated. The holiday observances continued into the early 20th century, declining during the push for integration during the civil rights movement of the 1960s.
During the ’70s, there was a resurgence of the Juneteenth celebration, and in 1980, Texas was the first state to make it an official state holiday. Today, 31 states celebrate Juneteenth as an official holiday or state observance, and a movement has been underway to make Juneteenth a federal observance. |
|Bulgaria Table of Contents
As in the case of World War I, Bulgaria fought on the losing German side of World War II but avoided open conflict with the Russian/Soviet state. Again the strains of war eroded public support and forced the wartime Bulgarian government out of office. But World War II heralded a drastic political change and a long era of totalitarian governance.
The Passive Alliance
Having failed to remain neutral, Boris entered a passive alliance with the Axis powers. The immediate result was Bulgarian occupation (but not accession) of Thrace and Macedonia, which Bulgarian troops took from Greece and Yugoslavia respectively in April 1941. Although the territorial gains were initially very popular in Bulgaria, complications soon arose in the occupied territories. Autocratic Bulgarian administration of Thrace and Macedonia was no improvement over the Greeks and the Serbs; expressions of Macedonian national feeling grew, and uprisings occurred in Thrace. Meanwhile, the Germans pressured Bulgaria to support the eastern front they had opened by invading the Soviet Union in June 1941. Boris resisted the pressure because he believed that Bulgarian society was still sufficiently Russophile to overthrow him if he declared war. After the Japanese attack on Pearl Harbor ended United States neutrality, Bulgaria declared war on Britain and the United States, but continued diplomatic relations with the Soviet Union throughout World War II. Acceleration of domestic war protests by the BCP in 1941 led to an internal crackdown on dissident activities of both the right and left. In the next three years, thousands of Bulgarians went to concentration and labor camps.
The German eastern front received virtually no aid from Bulgaria, a policy justified by the argument that Bulgarian troops had to remain at home to defend the Balkans against Turkish or Allied attack. Hitler reluctantly accepted this logic. Boris's stubborn resistance to committing troops was very popular at home, where little war enthusiasm developed. Nazi pressure to enforce anti-Jewish policies also had little support in Bulgarian society. Early in the war, laws were passed for restriction and deportation of the 50,000 Bulgarian Jews, but enforcement was postponed using various rationales. No program of mass deportation or extermination was conducted in Bulgaria.
In the summer of 1943, Boris died suddenly at age 49, leaving a three-man regency ruling for his six-year-old son, Simeon. Because two of the three regents were figureheads, Prime Minister Bogdan Filov, the third regent, became de facto head of state in this makeshift structure.
The events of 1943 also reversed the military fortunes of the Axis, causing the Bulgarian government to reassess its international position. Late in 1943, the Allies delivered the first of many disastrous air raids on Sofia. The heavy damage sent a clear message that Germany could not protect Bulgaria from Allied punishment. Once the war had finally intruded into Bulgarian territory, the winter of 1943-44 brought severe social and economic dislocation, hunger, and political instability. The antiwar factions, especially the communists, used urban guerrilla tactics and mass demonstrations to rebuild the organizational support lost during the government crackdown of 1941. Partisan activity, never as widespread as elsewhere in the Balkans during the war, increased in 1944 as the Red Army moved westward against the retreating Germans. To support antigovernment partisan groups, in 1942 the communists had established an umbrella Fatherland Front coalition backing complete neutrality, withdrawal from occupied territory, and full civil liberties.
Early in 1944, Bulgarian officials tried to achieve peace with the Allies and the Greek and Yugoslav governments-in-exile. Fearing the German forces that remained in Bulgaria, Filov could not simply surrender unconditionally; meanwhile, the Soviets threatened war if Bulgaria did not declare itself neutral and remove all German armaments from Bulgaria's Black Sea coast. Unable to gain the protection of the Allies, who had now bypassed Bulgaria in their strategic planning, Bulgaria was caught between onrushing Soviet forces and the last gambits of the retreating Nazis. At this point, the top priority of Bulgarian leaders was clearing the country of German occupiers while arranging a peace with the Allies that would deprive Soviet forces of an excuse to occupy Bulgaria. But in September 1944, the Soviet Union unexpectedly declared war on Bulgaria, just as the latter was about to withdraw from the Axis and declare war on Germany.
The Soviet Occupation
When Soviet troops arrived in Bulgaria, they were welcomed by the populace as liberators from German occupation. On September 9, 1944, five days after the Soviet declaration of war, a Fatherland Front coalition deposed the temporary government in a bloodless coup. Headed by Kimon Georgiev of Zveno, the new administration included four communists, five members of Zveno, two social democrats, and four agrarians. Although in the minority, the communists had been the driving force in forming the coalition as an underground resistance organization in 1942. The presence of the Red Army, which remained in Bulgaria until 1947, strengthened immeasurably the communist position in dealing with the Allies and rival factions in the coalition. At this point, many noncommunist Bulgarians placed their hopes on renewed relations with the Soviet Union; in their view, both Germany and the Allies had been discredited by the events of the previous fifteen years. In 1945 the Allies themselves expected that a benign Soviet Union would continue the wartime alliance through the period of postwar East European realignment.
The armistice signed by Bulgaria with the Soviet Union in October 1944 surrendered all wartime territorial gains except Southern Dobruja; this meant that Macedonia returned to Yugoslavia and Thrace to Greece. The peace agreement also established a Soviet-dominated Allied Control Commission to run Bulgaria until conclusion of a peace treaty. Overall war damage to Bulgaria was moderate compared to that in other European countries, and the Soviet Union demanded no reparations. On the other hand, Bulgaria held the earliest and most widespread war crimes trial in postwar Europe; almost 3,000 were executed as war criminals. Bulgaria emerged from the war with no identifiable political structure; the party system had dissolved in 1934, replaced by the pragmatic balancing of political factions in Boris's royal dictatorship. This condition and the duration of the war in Europe eight months after Bulgaria's surrender gave the communists ample opportunity to exploit their favorable strategic position in Bulgarian politics.
Source: U.S. Library of Congress |
In modern Korea, the Joseon Dynasty, also known as Yi Dynasty by the Japanese occupiers, (1392-1910 AD) became one of the longest reigns by a single dynasty in world history. During the dynasty, various kings, under the influence of Neo-Confucianism, introduced many social and cultural changes. The dynasty was considered Korea's "Age of Enlightenment," but it was also the beginning of the "dark ages" for martial arts in Korea.
After his defeat of the Mongols and driving out the Red Turbans "armies of red heads" in 1364 AD, General Yi Song Gye emerged as a leader of the Korean people. Yi came from a family that, for generations, had supplied military leaders to the Hamyong province in the northeast and he had a distinguished military career from suppressing local rebellions. After the Mongol defeat, General Yi turned his attention to curbing the constant Japanese pirate attacks that were becoming intolerable. He repelled the pirate attacks in his own northeastern area and then fought a series of engagements over the next few years that reduced their power and kept them more or less at bay.
These times were more a period of diplomacy than of continual war. When threatened from the north, Korea looked to Japan for assistance. When threatened from the south, she looked to China. Yi strongly supported Confucianism so he re-opened relations with China, re-established the central government, and provided the king with Confucian advisors. Confucianism began to replace Buddhism as a strong cultural force in Korea. With consolidated support from the ruling classes, General Yi rose to power.
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No single symptom positively identifies schizophrenia. An individual may have any combination of symptoms. Furthermore, an individual's symptoms can change over time. The symptoms of schizophrenia are divided into three categories: positive, negative and cognitive symptoms.
Positive Symptoms are also known as "psychotic symptoms" because the person has lost contact with reality in certain ways. Positive symptoms can include:
Delusions, which occur when someone believes ideas that are clearly false (e.g. people are reading their thoughts or that they can control other people's minds). These beliefs are frequently unusual and/or impossible. As found by a 2010 study, people living with schizophrenia are more prone to produce confabulations, the production of false memories without a deliberate intent to lie. However, unlike neurological disorders, memory impairment is not a prerequisite for confabulation.
Hallucinations, which are imagined voices or images inside or outside an individual's head.
Negative Symptoms are deficits or normal behavior and "take away" from the person's ability and usual way of interacting with the world. As a 2000 study in Advances in Psychiatric Treatment found, these symptoms can often be confused with depression. These symptoms can include:
Cognitive Symptoms pertain to thinking processes. People living with schizophrenia often struggle with executive functioning, memory and organizing thoughts. Another common cognitive deficit associated with schizophrenia is Anosognosia, as explained previously.
According to the DSM-IV, before diagnosis can be made, two of the following must be present for at least one month: delusions, hallucinations, disorganized speech, catatonic behavior and negative symptoms.
Often differentiating between mental illnesses can be difficult. Two similar, yet different, disorders are schizophrenia and schizoaffective disorder. While schizophrenia is characterized by the above symptoms, people living with schizoaffective disorder also experience symptoms of a mood disorder, such as mania or depression. To learn more about schizoaffective disorder go to NAMI's page on Schizoaffective Disorder. |
Neurophilosophy has a fascinating article on the recent archaeological discovery of numerous ancient Incan skulls of which over 1 in 6 showed signs of trepanation – an ancient form of brain surgery where a hole was drilled in the skull.
What’s surprising is just how common it was. 66 skulls from Incan burial sites had a total of 109 trepanation holes. Some, like the one pictured, obviously needed a significant amount of skill and practice to complete.
And with this many examples, the archaeologists could make some fascinating inferences about the purpose and success of these operations:
Andrushko and Verano argue that the Incas performed trepanation primarily to treat head injuries incurred during battle, because the holes are most often found at the front of the skull to the left, consistent with injuries caused by a right-handed opponent during face-to-face combat, and because adult males are overrepresented in the sample. The procedure was evidently used to treat mastoiditis (an infection of the region of the temporal bone behind the ear) as well.
The authors also show that the success rate of the procedure improved with time, as the Inca empire progressed and made advances in medicine. The earliest specimens, dated to around 1,000 A.D., showed no signs of bone growth around the perforations, suggesting that the procedure was often fatal. But specimens dating to around 400 years later suggest a survival rate of around 90%.
Link to Neurophilosophy article on prehistoric Inca neurosurgery. |
Arctic Tundra May Contribute to Warmer World
News story originally written on May 27, 2009
In 20 years of studying the Alaskan tundra, scientist Ted Schuur and his team have seen the frozen soil in their study area thaw, turning from hard ground to soft mud.
All over the Arctic, frozen soil, called permafrost, is thawing because of global warming. The team studied how the plants and soil change as permafrost thaws. Recently they have been developing new ways to monitor how thawing soil affects greenhouse gases in the atmosphere.
There is a large amount of carbon stored in the permafrost. The carbon built up in the soil over thousands of years from the remains of dead plants and animals which couldn’t decompose in frozen conditions. Today, as the soil thaws, carbon can be released into the atmosphere, increasing the amount of greenhouse gases.
A positive feedback to climate change happens when global warming causes something that, in turn, causes more warming. The process of a warmer climate causing permafrost thaw, which releases carbon to the atmosphere, which warms climate even more is an example of a positive feedback to climate change.
Carbon moves through different living and non-living parts of ecosystems in the carbon cycle, one of the biogeochemical cycles. The researchers wondered how carbon that has been in the frozen soils for hundreds to thousands of years, moved around the carbon cycle differently than carbon that was recently taken in by a plant. They used radiocarbon dating to figure out where old carbon moves in the carbon cycle as permafrost thaws.
Their results showed that when permafrost first begins to thaw, more plants are able to grow. The plants remove carbon from the atmosphere through the process of photosynthesis. This makes the amount of carbon taken out of the atmosphere greater than the amount added to the atmosphere from the soil. But the pattern does not continue this way. With more thawing, more carbon is added to the atmosphere than is taken out by plants.
This information is helping scientists make predictions about how much carbon will be released to the atmosphere from Arctic tundra in the future. |
The aluminum pendulum swinging back and forth in the center of the counter leaves a record of each oscillation in the tray of sand below.
Known as the Foucault Pendulum, after the French scientist who devised it, the demonstration is a graphic verification of the fact that the earth revolves about its axis.
Having once been set in motion, the pendulum obeys Newton’s Law of Motion by moving in a fixed plane. The earth, meanwhile, moves steadily eastward and describes a circle beneath the plane of the pendulum’s arc.
The length of time required for the pendulum to return to its starting point varies with latitude. At the equator there would be no change at all. At both poles the pendulum would make one apparent revolution about its base every 24 hours. Here in Seattle, the pendulum’s return to its starting point requires a little over 36 hours.
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Science Fair Project Encyclopedia
The term musical form is used in two related ways:
- a generic type of composition such as the symphony or concerto
- the structure of a particular piece, how its parts are put together to make the whole; this too can be generic, such as binary form or sonata form
Musical form (the whole or structure) is contrasted with content (the parts) or with surface (the detail), but there is no clear line between the two. In most cases, the form of a piece should produce a balance between statement and restatement, unity and variety, contrast and connection.
There is some overlap between musical form and musical genre. The latter term is more likely to be used when referring to particular styles of music (such as classical music or rock music) as determined by things such as harmonic language, typical rhythms, types of musical instrument used and geographical origin. The phrase musical form is typically used when talking about a particular type or structure within those genres. For example, the twelve bar blues is a specific form often found in the genres of blues and rock and roll music.
Forms and formal detail may be described as sectional or developmental, developmental or variational, syntactical or processual (Keil 1966), embodied or engendered, extensional or intensional (Chester 1970), and associational or hierarchical (Lerdahl 1983). Form may also be described according to symmetries or lack thereof and repetition. A common idea is formal "depth", necessary for complexity, in which foregrounded "detail" events occur against a more structural background. For example: Schenkerian analysis. Fred Lerdahl (1992), among others, claims that popular music lacks the structural complexity for multiple structural layers, and thus much depth. However, Lerdahl's theories explicitly exclude "associational" details which are used to help articulate form in popular music. Allen Forte's book The American Popular Ballad of the Golden Era 1924-1950 analyses popular music with traditional Schenkerian techniques, but this is only possible because pre-rock popular ballads are the genre most accessible similar to the Romantic music that those theories were designed to analyse. (Middleton 1999, p.144)
Extensional music is, "produced by starting with small components - rhythmic or melodic motifs, perhaps - and then 'developing' these through techniques of modification and combination." Intensional music "starts with a framework - a chord sequence, a melodic outline, a rhythmic pattern - and then extends itself by repeating the framework with perpetually varied inflections to the details filling it in." (Middleton, p.142)
- Western classical music is the apodigm of the extensional form of musical construction. Theme and variations, counterpoint, tonality (as used in classical composition) are all devices that build diachronically and synchronically outwards from basic musical atoms. The complex is created by combination of the simple, which remains discrete and unchanged in the complex unity...If those critics who maintain the greater complexity of classical music specified that they had in mind this extensional development, they would be quite correct...Rock however follows, like many non-European musics, the path of intensional development. In this mode of construction the basic musical units (played/sung notes) are not combined through space and time as simple elements into complex structures. The simple entity is that constituted by the parameters of melody, harmony, and beat, while the complex is built up by modulation of the basic notes, and by inflexion of the basic beat. All existing genres and sub-types of the Afro-American tradition show various forms of combined intensional and extensional development (Chester 1970, p.78-9).
Syntactic music is "centres" on notation and "the hierarchic organization of quasilinguistic elements and their putting together (com-position) in line with systems of norms, expectations, surprises, tensions and resolutions. The resulting aesthetic is one of 'embodied meaning.'" Non-notated music and performance "foreground process. They are much more concerned with gesture, physical feel, the immediate moment, improvisation; the resulting aesthetic is one of 'engendered feeling' and is unsuited to the application of 'syntactice' criteria" (Middleton 1990, p.115).
Middleton (p.145) also describes form, presumably after Gilles Deleuze’s Difference and Repetition (1968, translated 1994), through repetition and difference. Difference is the distance moved from a repeat and a repeat being the smallest difference. Difference is qualitative and quantitative, how far different and what type of difference.
In classical and popular music, there are many labels applied to forms, abstract formal designs, as contrasted with the principals and procedures of combining materials: form. Typical structures used to shape a single movement include:
In a sectional form, the larger unit (form) is built from various smaller clear-cut units (sections) in combination, sort of like stacking legos (DeLone, 1975):
- Introduction or Intro
- Chorus or refrain
- Bridge or interlude
- Coda or outro, and Fadeout
Developmental forms, larger unit (form) is built from small bits of material given different presentations and combinations, usually progressive (DeLone, 1975):
- Sonata form, also called sonata-allegro
Variational forms, larger unit (form) is built from sections treated to one type of presentation at a time, but varying succesively (DeLone, 1975):
- Rondo (ABACADA...)
- Variation form, sometimes theme and variation (AA'A"A"'...)
- Passacaglia and Chaconne
These structures are defined by the distribution of different thematic material, melodies, key centres, and other materials used. While many of the above forms are partly defined by their tonal schemes these forms may be applied to music which has a differing or no tonal scheme (DeLone et. al. (Eds.), 1975, chap. 1). More than one formal method may be used, including in-between types, and music which is not composed with the above or any other model is called through composed.
Especially recently, more segmented approaches have been taken through the use of stratification, superimposition , juxtaposition, interpolation, and other interruptions and simultaneities. Examples include the postmodern "block" technique used by composers such as John Zorn, where rather than organic development one follows separate units in various combinations. These techniques may be used to create contrast to the point of disjointed chaotic textures, or, through repetition and return and transitional procedures such as dissolution, amalgamation, and gradation, may create connectedness and unity. Composers have also made more use of open forms such as produced by aleatoric devices and other chance procedures, improvisation, and some processes. (ibid)
Types of piece which may or may not incorporate one or more of the above structures as part of their overall makeup include:
- Ballet, larger musical composition intended for Ballet dance form
- Dance, smaller musical composition intended for presentation of a dance, either as accompaniment for dancing or as music as such
- Etude or study
- Symphonic poem
- Category:Musical forms
- Song structure (popular music)
- Susan McClary's Constructions of Subjectivity in Schubert's Music
- Study Guide for Musical Form A Complete Outline of Standardized Formal Categories and Concepts by Robert T. Kelley
- DeLone et. al. (Eds.) (1975). Aspects of Twentieth-Century Music. Englewood Cliffs, New Jersey: Prentice-Hall. ASIN 0130493465.
- Lerdahl, Fred (1992). "Cognitive Constraints on Compositional Systems", Contemporary Music Review 6 (2), pp. 97-121.
- Richard Middleton. "Form", in Horner, Bruce and Swiss, Thomas, eds. (1999) Key Terms in Popular Music and Culture. Malden, Massachusetts. ISBN 0631212639.
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Butterflies are colorful, diverse, abundant, and active during the day in warm months, making them an ideal pursuit for wildlife watchers. Butterflies and caterpillars provide food for birds and other animals and pollinate flowers. Also, butterflies are easy to attract to a garden or backyard landscape if a few simple principles are followed.
Butterflies have a complex life cycle.
Diversity of Caterpillar Host Plants – Butterflies have a complex life cycle that begins as an egg that hatches into a caterpillar. The caterpillar is the larval stage in the life cycle. After weeks of eating, a caterpillar molts into a mummy-like stage with a hard protective casing, called a pupa or chrysalis. After about 2 weeks, the adult emerges from the chrysalis and begins searching for food and a mate to begin the cycle again. The adult female butterfly seeks out a specific host plant to lay its eggs because butterfly caterpillars are voracious but picky eaters, and many species of caterpillar feed only on a particular species of plant. For example, the monarch caterpillar feeds only on the foliage of milkweed. Therefore, it’s important to provide a good diversity of native host plants to attract a wide variety of butterflies and their caterpillars. A landscape comprised of mostly exotic plants might attract nectaring adults but it will not provide the specific food needs of caterpillars.
American lady butterflies nectar at blooming plants throughout the year.
Early and Late Blooming Nectar Plants – Because different species of butterfly are active from early spring through late fall, provide a diversity of plants that will bloom and provide nectar throughout the growing season.
Large butterflies like the tiger swallowtail nectar at larger blooms.
Flowers of Different Sizes and Depths – As adults, butterflies are much less specialized than caterpillars and will visit many different plant species as they seek out nectar. However, small butterflies tend to nectar at flowers with small blooms while larger butterflies tend to nectar from large flower blooms. Smaller butterflies, such as hairstreaks and skippers, have shorter proboscises (a straw-like “tongue”) and are unable to reach the nectar in larger blooms. Larger butterflies, such as swallowtails, favor larger blooms.
Small butterflies like the red-banded hairstreak nectar at small blooms.
Sunny Location – Most butterflies are active only in the sun and many butterfly larval and nectar plants require sunny habitats.
Puddling Areas – Male butterflies often congregate at “puddling” areas, which include mud puddles, moist soil along stream banks, and animal feces. There they ingest the salts important in sperm production. Make puddling easy for male butterflies by designing water puddles and wet, sandy areas into the habitat.
Winter Habitats – Most species of butterflies survive the winter by hibernating as caterpillars, pupae, or adults. A few spend the winter as eggs. Fewer still migrate to warmer climates.
• To provide areas for adults to spend the winter, leave snags (standing dead trees) or brush piles in your landscape. There is little evidence to suggest that butterflies actually use butterfly houses.
• Throughout the growing season and in the fall, leave dead flower heads and dead foliage on your plants or you may accidentally remove eggs or pupating butterflies.
Ripe or Rotting Fruit – Peelings and cores of fruit (peeled, overly ripe bananas work well) can be discarded in partially shaded nooks in the garden where they will attract butterflies that eat rotting fruit. Butterfly species that eat old fruit or tree sap include question mark, eastern comma, and hackberry emperor.
Allocate some individual plants for feeding black swallowtail caterpillars.
Minimize Use of Pesticides – Chemicals that kill insect pests also kill butterflies and other beneficial insects. If caterpillars are eating your favorite plants (e.g., black swallowtail caterpillars are eating your parsley), allocate a few individual plants as host plants. Remove and relocate caterpillars from other individual plants to the ones dedicated as host plants.
Do Not Release Store-Bought Butterflies – Released butterflies can spread diseases to the native butterfly population. Also, they may interbreed with the native population, causing genetic problems or interfering with natural migration patterns. Generally, exotic butterflies die quickly.
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Traditional Japanese legend maintains that Japan was founded in 600 BC by the Emperor Jimmu, a direct descendant of the sun goddess and ancestor of the present ruling imperial family. About AD 405, the Japanese court officially adopted the Chinese writing system. Together with the introduction of Buddhism in the sixth century, these two events revolutionized Japanese culture and marked the beginning of a long period of Chinese cultural influence. From the establishment of the first fixed capital at Nara in 710 until 1867, the emperors of the Yamato dynasty were the nominal rulers, but actual power was usually held by powerful court nobles, regents, or "shoguns" (military governors).
Contact With the West
Within several years, renewed contact with the West profoundly altered Japanese society. The shogunate was forced to resign, and the emperor was restored to power. The "Meiji restoration" of 1868 initiated many reforms. The feudal system was abolished, and numerous Western institutions were adopted, including a Western legal system and constitutional government along quasi-parliamentary lines.
In 1898, the last of the "unequal treaties" with Western powers was removed, signaling Japan's new status among the nations of the world. In a few decades, by creating modern social, educational, economic, military, and industrial systems, the Emperor Meiji's "controlled revolution" had transformed a feudal and isolated state into a world power.
Wars With China and Russia
World War I to 1952
During the 1920s, Japan progressed toward a democratic system of government. However, parliamentary government was not rooted deeply enough to withstand the economic and political pressures of the 1930s, during which military leaders became increasingly influential.
Japan invaded Manchuria in 1931 and set up the puppet state of Manchukuo. In 1933, Japan resigned from the League of Nations. The Japanese invasion of China in 1937 followed Japan's signing of the "anti-Comintern pact" with Nazi Germany the previous year and was part of a chain of developments culminating in the Japanese attack on the United States at Pearl Harbor, Hawaii, on December 7, 1941.
After almost 4 years of war, resulting in the loss of 3 million Japanese lives and the atomic bombings of Hiroshima and Nagasaki, Japan signed an instrument of surrender on the U.S.S. Missouri in Tokyo Harbor on September 2, 1945. As a result of World War II, Japan lost all of its overseas possessions and retained only the home islands. Manchukuo was dissolved, and Manchuria was returned to China; Japan renounced all claims to Formosa; Korea was granted independence; southern Sakhalin and the Kuriles were occupied by the U.S.S.R.; and the United States became the sole administering authority of the Ryukyu, Bonin, and Volcano Islands. The 1972 reversion of Okinawa completed the U.S. return of control of these islands to Japan.
After the war, Japan was placed under international control of the Allies through the Supreme Commander, Gen. Douglas MacArthur (the last Shogun in Japanese history). U.S. objectives were to ensure that Japan would become a peaceful nation and to establish democratic self-government supported by the freely expressed will of the people. Political, economic, and social reforms were introduced, such as a freely elected Japanese Diet (legislature) and universal adult suffrage. The country's constitution took effect on May 3, 1947. The United States and 45 other Allied nations signed the Treaty of Peace with Japan in September 1951. The U.S. Senate ratified the treaty in March 1952, and under the terms of the treaty, Japan regained full sovereignty on April 28, 1952.
The post-World War II years saw tremendous economic growth in Japan, with the political system dominated by the Liberal Democratic Party (LDP). That total domination lasted until the Diet Lower House elections on July 18, 1993 in which the LDP, in power since the mid-1950s, failed to win a majority and saw the end of its four-decade rule. A coalition of new parties and existing opposition parties formed a governing majority and elected a new prime minister, Morihiro Hosokawa, in August 1993. His government's major legislative objective was political reform, consisting of a package of new political financing restrictions and major changes in the electoral system. The coalition succeeded in passing landmark political reform legislation in January 1994.
In April 1994, Prime Minister Hosokawa resigned. Prime Minister Tsutomu Hata formed the successor coalition government, Japan's first minority government in almost 40 years. Prime Minister Hata resigned less than 2 months later. Prime Minister Tomiichi Murayama formed the next government in June 1994, a coalition of his Japan Socialist Party (JSP), the LDP, and the small Sakigake Party. The advent of a coalition containing the JSP and LDP shocked many observers because of their previously fierce rivalry. Prime Minister Murayama served from June 1994 to January 1996. He was succeeded by Prime Minister Ryutaro Hashimoto, who served from January 1996 to July 1998. Prime Minister Hashimoto headed a loose coalition of three parties until July 1998, when he resigned due to a poor electoral showing by the LDP in Upper House elections. He was succeeded as LDP President and Prime Minister by Keizo Obuchi, who took office on July 30, 1998.
The LDP formed a governing coalition with the Liberal Party in January 1999, and Keizo Obuchi remained prime minister. The LDP-Liberal coalition expanded to include the Komeito Party in October 1999. Prime Minister Obuchi suffered a stroke in April 2000 and was replaced by Yoshiro Mori. After the Liberal Party left the coalition in April 2000, Prime Minister Mori welcomed a Liberal Party splinter group, the New Conservative Party, into the ruling coalition. The three-party coalition made up of the LDP, Komeito, and the New Conservative Party maintained its majority in the Diet following the June 2000 Lower House elections. The next Lower House election must be held by June 2004.
After a turbulent year in office, Prime Minister Mori agreed to hold early elections for the LDP presidency in order to improve his party's chances in crucial July 2001 Upper House elections. Riding a wave of grassroots desire for change, political maverick Junichiro Koizumi won an upset victory on April 24, 2001 over former Prime Minister Hashimoto and other party stalwarts on a platform of
economic and political reform. Koizumi was elected as Japan's 87th Prime Minister on April 26, 2001. The New Conservative Party dissolved in December 2002, and elements of it and defectors from the opposition DPJ formed the Conservative New Party (CNP). The CNP joined the coalition with the LDP and Komeito at its inception. Prime Minister Koizumi was re-elected as LDP President on September 20,
2003, securing a second 3-year term as Prime Minister. In the fall of 2003, the Liberal Party merged with the Democratic Party of Japan, combining party identification under the DPJ name. In congressional elections held in November of 2003, the DPJ won 40 seats, bringing to 177 the total number held by the party. This result has brought Japan as close as it has ever been to a two-party political
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Continental Drift and Plate-Tectonics Theory
Source: U.S. Dept. of the Interior, Geological Survey
According to the theory of continental drift, the world was made up of a single continent through most of geologic time. That continent eventually separated and drifted apart, forming into the seven continents we have today. The first comprehensive theory of continental drift was suggested by the German meteorologist Alfred Wegener in 1912. The hypothesis asserts that the continents consist of lighter rocks that rest on heavier crustal material—similar to the manner in which icebergs float on water. Wegener contended that the relative positions of the continents are not rigidly fixed but are slowly moving—at a rate of about one yard per century.
According to the generally accepted plate-tectonics theory, scientists believe that Earth's surface is broken into a number of shifting slabs or plates, which average about 50 miles in thickness. These plates move relative to one another above a hotter, deeper, more mobile zone at average rates as great as a few inches per year. Most of the world's active volcanoes are located along or near the boundaries between shifting plates and are called plate-boundary volcanoes.
The peripheral areas of the Pacific Ocean Basin, containing the boundaries of several plates, are dotted with many active volcanoes that form the so-called Ring of Fire. The Ring provides excellent examples of plate-boundary volcanoes, including Mount St. Helens.
However, some active volcanoes are not associated with plate boundaries, and many of these so-called intra-plate volcanoes form roughly linear chains in the interior of some oceanic plates. The Hawaiian Islands provide perhaps the best example of an intra-plate volcanic chain, developed by the northwest-moving Pacific plate passing over an inferred “hot spot” that initiates the magma-generation and volcano-formation process.
Fact Monster/Information Please® Database, © 2007 Pearson Education, Inc. All rights reserved.
More on Continental Drift and Plate-Tectonics Theory from Fact Monster: |
Scientists Use Mathematical Shortcut to Create New Metals
CREDIT: Eugene Sergeev | Shutterstock
To create new alloys, metallurgists for centuries have relied on trial and error. That could change.
A group of scientists at the Massachusetts Institute of Technology has come up with a mathematical model that lets them predict what kinds of alloys will be stable, without having to go through the laborious process of making them and trying them out.
Most metals consist of tiny crystals at the nanometer scale. This is what gives metals their varying properties – their hardness or ductility, for example. In many high-tech metals, building an alloy with lots of nanocrystals can boost hardness. But these structures aren't stable; as the temperature goes up or the metal is stressed, the crystals merge and get bigger (they essentially melt), and the properties that made them special are lost.
Tongjai Chookajorn, Heather Murdoch and Christopher A. Schuh came up with a way to make a map of a given element's stability at a certain temperature, using a mathematical model. It lets metallurgistssee what other elements they can add to the base metal (known as a matrix or solvent) to get stable structures and keep them intact at high temperatures.
The team tested tungsten, which is one of the strongest metals known and has the highest melting temperature. Schuh told InnovationNews Daily that the high melting temperature means it needs to be hot in order to be processed, so keeping the nanocrystal structures stable is a lot harder to do. The mathematical model, developed by Murdoch, suggested a few candidates that would allow the structures to stay stable, such as titanium, zinc, chromium and gold. It also showed that copper, cadmium and strontium would not work.
After deciding to use titanium (which also is strong and has a high melting point), Chookajorn tackled making the actual alloy. The alloy worked as the model said it would: At 2,012 degrees Fahrenheit (1,100 degrees Celsius), the nanocrysals stayed stable for a week.
Another thing the new model does is indirectly show how the alloying material mixes with the base. To maximize strength, the secondary metal – in this case titanium – has to gather near the boundaries of the nanocrystal structures. When that happens, the nanocrystals are more likely to remain stable. Chookajorn said they are working on another model to look into the actual structure of alloys.
The group has tried its technique with other metals, though it hasn't tried making the actual alloys yet. "We do expect that when experiments are done, it will lead to new nanostructured alloys with high stability and which were not previously made," Schuh wrote in an email.
The research is detailed in the Aug. 24 issue of the journal Science.
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Use these free reading worksheets to help you get involved with your child’s education. Worksheets are one of many tools available that can help you teach your kids to read. Make it a fun time and personalize the sheets to your child’s interests.
As a parent, you know your children better than anyone. Exposing your kids to a wide variety of learning tools will help you determine which methods are most effective in helping them learn better.
Worksheets are a great learning tool, but make sure to keep learning sessions short and fun so your kids will always look forward to learning. Using the reading worksheets should never seem like a chore.
Reading worksheets can be fun as well as educational. Here are some free reading worksheets to help your beginning readers. You can use these or create your own.
Click on the links below to download or print your worksheets.
Practice the writing the different letters of the alphabet in both lower and upper case.
Identify all the different vowel sounds. This one is fun and challenging for your beginning readers.
Learn to recognize all the letters of the alphabet. Be a detective and find each letter. |
The wartime brainchild of British scientist Geoffrey Pyke, Project Habbakuk envisaged the creation of an aircraft carrier made of ice.
The project took its name from Habakkuk, the Old Testament prophet:
'Behold ye among the heathen, and regard and wonder marvellously: for I will work a work in your days, which ye will not believe, though it be told to you.'
The iceberg aircraft carrier was planned to provide aircraft to operate in the mid-Atlantic, to combat Germany's submarine menace. Thereafter, the assault on mainland Europe was to be launched
from the giant 'berg ship'.
Both Mountbatten and Churchill supported the project, and Pyke deemed his ship unsinkable, as well as cheap to produce, using Pykrete, a compound of paper pulp and sea water. A model ship was built in in Canada and Pykrete demonstrated its strength in firing trials, but the enormity of the project proved to
great to bear. The project was abandoned before the end of the war. |
The world's first meteorological satellite, was launched from Cape Canaveral on April 1, 1960. Named TIROS for Television Infrared Observation Satellite, it demonstrated the advantage of mapping the earth's cloud cover from satellite altitudes. TIROS showed clouds banded and clustered in unexpected ways. Sightings from the surface had not prepared meteorologists for the interpretation of the cloud patterns that the view from an orbiting satellite would show.
TIROS was a polar orbiting satellite. Polar orbiting satellites (POES) continued to be used today and offer the advantage of daily global coverage, by making nearly polar orbits roughly 14.1 times daily. Since the number of orbits per day is not an integer, the orbital tracks do not repeat on a daily basis. Currently in orbit we have morning and afternoon satellites, which provide global coverage four times daily.
The geostationary (GOES) satellites were placed in orbit beginning in 1966. Unlike POES satellite, GOES satellites orbit at an altitude of 22,236 miles (35,786 km). At this distance the satellite completes one orbit of the earth in 24 hours. The net result is the satellite appears stationary, relative to the earth. This allows them to hover continuously over one position on the surface. Because they stay above a fixed spot on the surface, they provide a constant vigil for the atmospheric "triggers" for severe weather conditions such as tornadoes, flash floods, hail storms, and hurricanes.
There are advantages and disadvantages to each kind of orbit. |
(c. 429-347 BC)
Plato was born in Athens of an aristocratic family. He recounts in the Seventh Letter, which, if genuine, is part of his autobiography, that the spectacle of the politics of his day brought him to the conclusion that only philosophers could be fit to rule. After the death of Socrates in 399, he travelled extensively. During this period he made his first trip to Sicily, with whose internal politics he became much entangled. He visited Sicily at least three times in all and may have been richly subsidised by Dionysius. On return from Sicily he began formal teaching at what became the Academy.
Plato is generally regarded as the inventor of the philosphical argument as we know it, and many would claim that the depth and range of his thought have never been surpassed.
Plato's fame rests on his Dialogues which are all preserved. They are usually divided in three periods, early, middle, and late. The early dialogues establish the figure of Sokrates, portrayed as endlessly questioning, shattering the false claims of his contemporaries. The middle dialogues are not in dialogue form, and not exhibit the Socratic method. It is the middle dialogues that defend the doctrines commanly thought of as the Platonism. In the late works, especially the last and longest dialogue, the Laws, Plato return to the to the character of the ideal republic in a more sober manner, with civic piety and religion take much of the burden of education away from philosophy.
Last modified August 16, 1995. |
Pediatricians can protect your child by administering not only active immunizations, but sometimes they can use what physicians call passive immunizations. If you hear your pediatrician use these terms, this is what they mean.
When your child receives an active immunization, the vaccine prevents an infectious disease by activating the body’s production of antibodies that can fight off invading bacteria or viruses. Passive immunization, in which antibodies against a particular infectious agent are given directly to the child or adult, is sometimes appropriate. These antibodies are taken from a donor and then processed so the final preparation contains high antibody concentrations. At that point, they are given in the vein or by shot to the patient.
Passive immunization is often used in children and adults who have weakened immune systems or may not be good candidates for routine vaccinations for other reasons. It can be used with people who haven’t been vaccinated against a disease to which they’ve been exposed. For example, the passive rabies immunization (rabies immune globulin) is commonly used after a certain type of wild animal bites a child. Passive immunizations for hepatitis A (gamma globulin) may be helpful for people traveling to a part of the world where hepatitis A is common. They are typically given before children or adults leave on their trip. These are used less now that there is a vaccine for hepatitis A.
If there is enough time, the active vaccination is preferable. Keep in mind that passive immunizations provide only short-term protection that often lasts just a few weeks before the antibodies are worn down and removed from the bloodstream. By contrast, active immunizations can produce antibodies that last a lifetime. |
Vermont Votes for Kids: A project of the Vermont Secretary of State
Teacher Materials for Lesson 3:
Dimpled Ballots, Hanging Chads and Reform
Vermont has never faced problems as large as Florida's in the 2000 presidential election. This is in large part because we stopped using voting machines in the 1980s and every town must follow the same rules when it counts and recounts ballots. But we are as vulnerable to human error as any state in the country. Vermont has had its own share of problems, albeit on a much smaller scale. For example, a court in Chittenden County threw out a local election because the town could not explain why more ballots were cast in the election than voters were checked off on the voter checklist.
Students need to understand that their adult leaders are trying to learn from mistakes by making improvements in the election system. They need to feel that steps are being taken to enhance the reliability and credibility of voting results.
This lesson will:
Vermont's response to the issues generated by the 2000 Presidential election are reviewed in two articles published in 2003 by former Secretary of State Deborah Markowitz: Majority Rule in Vermont's Elections, and Election Reform – Challenges and Opportunities. These can be found at http://www.sec.state.vt.us/secdesk/commentary/2003comm.html
Copy Student Lesson Three for each student. As an introduction, you may choose to teach them the background above. It is recommended that you also prepare a brief overview of the infamous voting problems associated with the 2000 Presidential Election. You should explain the difference between ballot system "reliability" (to produce accurate and consistent results) and "credibility" (to engender public confidence in the voting system.) Individually or in small groups, ask the students to examine the challenges posed by the Secretary of State's articles. Next ask them to address the questions that follow, either in writing or as a class discussion.
An extension activity you might suggest to one or more students is to write a letter to the Secretary of State (firstname.lastname@example.org), or to their State Representative, or U.S. Congressional member expressing their views on election reforms. This could be in support or in opposition to one of those listed on their activity sheets or it could be their original suggestions for reforms not listed.
Vermont Secretary of State http://www.vermontvotesforkids.com |
Woodrow Wilson - American neutrality 1914—1916
With the outbreak of a general war in Europe in early August 1914, the great majority of Americans gave thanks for the Atlantic Ocean. Wilson and his advisers acted quickly to establish formal neutrality and to meet the rude shocks caused by the total disorganization of world markets and trade. In addition, Wilson, on 17 August 1914, appealed to his "fellow countrymen" to be "impartial in thought as well as in action."
Wilson then turned his attention to British encroachments against neutral trade with Germany and Austria-Hungary (the Central Powers). He first tried to persuade the British to adhere to the Declaration of London of 1909, which purported to codify existing international law and was extremely protective of neutral commerce. But the British were determined to use their overwhelming sea power to cut Germany off from life-giving supplies, and Wilson had no recourse but to fall back upon ambiguous international law to protect American trading rights. This he did in a note to the British Foreign Office on 26 December 1914.
The European theater of war was in delicate balance by the end of 1914. The British controlled the seas, and the French and British armies had repelled a German advance toward Paris. German armies in the east were on the move in Poland, but they were still far from their main eastern enemy, Russia. In these circumstances of stalemate, American neutrality seemed secure.
The announcement by the German government on 4 February 1915 that it would thereafter use its small submarine fleet to sink all Allied ships within a broad war zone without warning posed a grave threat to American neutrality, since the Germans also said that, because submarine commanders would sometimes find it impossible to discriminate between enemy and neutral ships, neutral ships would not be safe from torpedoes. Wilson, on 10 February, sent a conventional warning to Berlin to the effect that the United States would hold Germany to a "strict accountability" for the destruction of American ships and lives on the high seas. What that warning meant in practical terms, no one, including the leaders in Washington, knew. For example, when a submarine sank a British passenger ship without warning off the coast of Africa on 28 March 1915 and caused the death of one American, Wilson decided not to act or even to protest. However, it was impossible to do nothing when a submarine sank the great British liner Lusitania without warning on 7 May 1915, causing the death of more than 1,200 noncombatants, including 128 Americans.
Wilson was in a dilemma worse than the one occasioned by his occupation of Veracruz. It was obvious that the American people wanted him to defend their right to travel in safety upon the seas; it was also obvious that a majority of Americans and of the members of Congress did not want to go to war to vindicate this right. Moreover, the cabinet and Wilson's advisers in the State Department were about evenly divided over a wise and proper response to the sinking of the Lusitania . Secretary of State Bryan pleaded with Wilson to acquiesce in the submarine blockade by warning Americans not to travel on Allied ships. Robert Lansing, then second in command of the State Department, pressed Wilson to send a peremptory demand to Germany for an apology, a disavowal, and a promise that submarines in the future would obey international law—that is, commanders would have to warn ships and permit passengers and crews to escape before the ships were sunk.
Wilson, taking high humanitarian ground, addressed two appeals to the German government to abandon the entire submarine campaign, at least against unarmed and unresisting liners and merchantmen. When the German government refused, Wilson, on 21 July, sent a third note, which admitted that it was possible to conduct a submarine campaign in substantial accordance with international law. But the note ended with the warning that the United States government would hereafter regard ruthless attacks on merchant ships and liners, when they affected American citizens, as "deliberately unfriendly"—that is, as an act of war.
Wilson desperately wanted to avoid war. At the very time that he was writing the Lusitania notes, he sent two moving appeals to the German government to join him in a campaign to establish real freedom of the seas—that is, to force the British to observe international law. Wilson also planned to rally the other neutrals to win the same objective. But the civilian leaders in Berlin were engaged in a desperate struggle with military and naval leaders over submarine policy and could not return a positive response to Wilson's overtures. Had they done so, the outcome of the war might well have been very different.
Bryan resigned as secretary of state on 8 June rather than continue a correspondence that he said might eventuate in hostilities with Germany. Wilson, somewhat reluctantly, appointed Lansing to succeed Bryan. Wilson continued to maintain close personal control over important foreign policies, but it was hard to do this with Lansing in command at the State Department because the new secretary, bent on war with Germany, tried at critical points to thwart or undermine Wilson's diplomacy. Lansing was also, by Wilson's standards, legalistic and reactionary.
The crisis with Germany came to a sudden head when the commander who had sent the Lusitania to the bottom sank another large British liner, the Arabic , without warning on 19 August 1915, with forty-four casualties, including two Americans. Wilson did not resort to public correspondence, but he made it clear to the German government that he would break diplomatic relations if it did not disavow the sinking of the Arabic and promise that submarines would thereafter warn unarmed passenger ships and provide for the safety of their passengers and crews before sinking them. Kaiser Wilhelm II finally hardened his courage and, on 30 August 1915, ordered his naval commanders to cease the submarine campaign against all passenger ships. Under instructions from his superiors, the German ambassador in Washington, Count Johann Heinrich von Bernstorff, informed Lansing on 1 September, "Liners will not be sunk by our submarines without warning and without safety of the lives of noncombatants, provided that the liners do not try to escape or offer resistance."
Americans hailed the so-called Arabic pledge as a great triumph for their president. Actually, what Wilson had done was to narrow the submarine dispute to the sole issue of the safety of unarmed passenger ships. Submarines were still free to prowl the seas and sink merchantmen without warning. The kaiser called all submarines back to their bases temporarily, in order to avoid any further incidents. But the Germans had not renounced the important aspects of the underseas campaign—the war against merchant shipping—and Wilson had in effect withdrawn his demand that they do so. |
Green Projects for Students
6 of 10 in Series: The Essentials of Living Green with Children
The ultimate goal of making schools eco-friendly is to get the children involved in projects that help build a greener community. If the school uses renewable energy, recycles, and composts food waste, it demonstrates green living in action to children, parents, and people in the wider community.
A range of projects is the ideal so that everyone in the school — from the youngest and most academically minded to the oldest and most practically minded — can be engaged and involved. Some ideas include:
Dig a vegetable plot: Devote spare land on school grounds to a vegetable plot. Students can grow organic vegetables to use in the school cafeteria or to donate to local food banks. In the process of planting, monitoring, and caring for an organic garden, students learn about organic production, local and seasonal food, and the link between the land and what ends up on their plates.
If funding is an issue, seek sponsorship from the local community. Garden centers may be interested in providing tools, seeds, and expert advice, for example, or community organizations may provide funds to buy fencing to protect the garden from rabbits and other wildlife eager to sample the produce.
Visit the local landfill site and recycling facility: Taking children to a landfill to see the reality of waste management can have a big impact on their habits. Incorporate the following activities in the landfill visit to get children involved and thinking about waste management:Credit: PhotoDisc/Getty ImagesSeeing where trash ends up can serve as a wake-up call to children.
Ask them to identify things that could have been reused, repaired, or recycled.
Explain how long it takes various items they see to decompose.
Explain how toxic chemicals have to be prevented from getting into the ground and local water supplies.
Discuss the various other options for getting rid of and reducing the waste to a minimum in the first place.
From the landfill site, go to a local recycling facility if you can, and show the children what happens to the items sorted and processed there.
Plant trees: If the school has no land of its own on which to grow trees, find a local park or playground open to the project. Don’t forget that part of the project is monitoring the growth and health of the trees, so choose a fast-growing species suitable for your environment.
Launch a green competition: Friendly competitions give children incentives to work, and green projects are an ideal opportunity to provide a little extra incentive for extra effort. The competition may be to find the students who come up with the best green project of the year or who write the best essays on a specific green issue, for example. Every aspect of the competition — including letting the kids and their parents know about it — should help to raise awareness about green living and green schools.
Prizes can come from you if you can afford them, or you may ask local green companies to donate either goods or funds for the prizes. It’s best if the prizes contribute to green living, too. |
In lessons such as Mr. Angelo’s, mathematics entails following rules and practicing procedures, often with little attention to the underlying concepts.5 Procedural fluency is given central attention. Adaptive reasoning is not Mr. Angelo’s goal: He does not offer a justification for the rule he is teaching, nor does he engage students in reasoning about the structure of the place-value notation system that is its foundation. He focuses instead on ensuring that they can use it correctly. Other aspects of mathematical proficiency are also not on his agenda. Instead, Mr. Angelo has a clear purpose for the lesson, and to accomplish that purpose he controls its pace and content. Students speak only in response to closed questions calling for a short answer, and students do not interact with one another. When a student gets an answer wrong, Mr. Angelo signals that immediately and asks someone else to provide the correct answer. The lesson is paced quickly.
We turn now to our second teacher, Ms. Lawrence, who is working with her fifth graders on adding fractions (Box 9–3). Ms. Lawrence’s goals are different from Mr. Angelo’s. Although she also structures the lesson to accomplish her goals, unlike Mr. Angelo, she emphasizes explanation and reasoning along with procedures. The pace of the lesson is carefully controlled to allow students time to think but with enough momentum to engage and maintain their interest.
Box 9–3 Ms. Lawrence— Teaching Fifth Graders About Adding Fractions
After a few minutes in which the class does mental computation to warm up, Ms. Lawrence reviews equivalent fractions by asking the students to provide other names for She asks the class what fractions are called that “name the same number.” On the chalkboard she writes a problem involving the addition of fractions with like denominators:
She asks the students how to find the sum. One student, Betsy, volunteers that you just add the numerators and write the sum over the denominator. “Why does this work?” Ms. Lawrence asks. She asks Betsy to go to the board and explain. Confidently, Betsy draws two pie diagrams, one for each fraction, and explains that the denominator tells the size of the pieces and the numerators how many pieces all together: |
To see how this works, let's review some basic operations on vectors. The addition of two vectors can be shown graphically. It works as might be expected: Two vectors and add up to . Here is how it looks in a graph:
Notice how the first vector starts from the origin (0,0). The second vector is then placed with its tail (the end with no arrow head) to the head of the first. The combination of the two is the same as a vector starting from the origin connecting to the head of the second one. Subtraction follows in a similar fashion, but reverses the direction of the second vector.
Graphing addition like this, a collection of vectors (each representing a line) can be used to create basic images, a vector version of connect-the-dots. Although our example is simple in nature, many vectors can be combined to generate complex drawings.
Let's try an example to illustrate what can be done. Following is a complete Python program that uses both the Numeric (NumPy) module as well as pxDislin. What is new from last month is the use of the
dMultiLine function, which draws a line (vector) between points of
y_list arguments. Essentially, the dMultiLine function is performing a vector addition operation. The function does not actually do the math, but it does graphically represent the operation. The points chosen trace out a simple box structure of a house centered on the plot axis.
from pxDislin import * from Numeric import * plot = dPlot() axis = dAxis(-20,20,-20,20) plot.add_axis(axis) house_pts = array([[5,5,-5,-5,5,4,4,2,2,5,5,0,-5], [-5,5,5,-5,-5,-5,-1,-1,-5,-5,5,8,5]]) house = dMultiLine(house_pts,house_pts) plot.add_object(house) plot.show()
The generated plot is:
The points that draw out the house are essentially a 2-by-13 matrix:
where the x coordinates are in the top row and the y coordinates are the bottom row. Each column of the matrix may be taken as a 2-by-1 vector, and as such the matrix is a collection of 13 column vectors. |
Of the Greek Philosophers, Aristotle probably has the largest body of surviving work. While Greek philosophy before Socrates and Plato was generally written in verse (Really), and all of Plato's works in dialogues, Aristotle's works appear as prose treatises, usually in major works outlining principles of a study, and smaller treatises about specific topics, for example the dissection of marine animals. The major works are usually identified as Metaphysics, Physics, Politics, Nicomachean Ethics, On the Soul, The History of Animals/On the Parts of Animals/On the Generation of Animals, Rhetoric and Poetics. The genre of all his work is somewhat uncertain. While the Nicomachean Ethics is quite approachable, and at time indicates it may be written as a long argumentative epistle (possibly about a very specific issue at hand), the Metaphysics and other treatises are rather dense and difficult, and may be either one of his students' lecture notes (which we know is true of the Constitution of Athens), or written as his attempts to severely compress the material (which Aquinas and the scholastics believed).
The usual route taken in understanding Aristotle is taking his philosophy as opposed to Plato's. While Plato believes nearly everything to be originating in eternal forms ultimately alien to the world, Aristotle believes most things in the universe are defined strictly by their properties. This led him to more modern means of investigation, like experimenting rather than speculating as far from the evidence as possible. He was widely skilled in dissection, and many of his treatises about the parts of animals seem very modern because of it. Hence the focal point of Raphael's painting The School of Athens being Plato pointing up to "heavenly" forms and Aristotle point down to "things as they are."
However, Aristotle believed, with Plato, in at least some governing principle giving design to the Universe. His proof (in The Metaphysics) of this did not necessarily lie with the way things themselves were made (as Plato's argument was), but based on the pre-Socratic Parmenides, tracing all motion back; eventually to what a conception his commentators would call causality. It requires the force of an Original Unmoved Mover. The result is a doctrine much more complicated than it's usual modern intepretation, which is often blamed (by modern Aristotelians) on Plotinus' simplistic fetishization of the Unmoved Mover argument. The full argument for and about causation for Aristotle is prevalent throughout the rest of his work, including the Nicomachean Ethics, and leads him to some shockingly novel ideas about human responsibility, and the nature of action. Like it or Not, Causality principles are also one of the only ways of bypassing the is-ought problem.
His works were lost to Europe during the Middle Ages, except for Categories and On Interpretation. The rest of them were, at the time, still very popular and wide-spread in the Muslim East, and the first attempts to reclaim them were usually clumsy back-translations from Arabic translations in the tenth century. In the Twelfth Century, Thomas Aquinas (yes, again) asked William of Moerbeke to translate some of the recently retrieved Greek manuscripts into Latin (proficiency in Early Greek was extremely rare in the Middle Ages), which he did with shocking objectivity, not adding any marginal glosses nor making distinctions of heretical or kosher material. Some point to this as the first gesture towards the Renaissance and Enlightenment.
Aristotle's four elements, Earth, Air, Fire, and Water were an early attempt to describe all of nature as being composed of basic substances. They were believed to be counterparts of four of the five Platonic bodies, tetrahedron, cube, octahedron, and icosahedron. The fifth element, "quintessence" was conceived as a counterpart of the dodecahedron, and it was believed to be the material of the Moon, the planets and the stars.
As such, it took the West a long time to get over the fundamental errors (we all make mistakes, after all) and get things moving in a positive direction. The early Common Era in the West was marked with a high degree of dogmatism, as opposed to the fluid condition of philosophy in Greece, so instead of arguing with, improving, or even overthrowing Aristotelian concepts, his ideas were rather set in stone, contrary to how he and his peers treated ideas in his time.
Many credit Aristotle as being the first true scientist in the West, despite the ossification of science in the wake of the abuse of his principles[clarification needed]. |
A History Fair Argument is Composed of the Thesis, Claims, Evidence
Crafting Your Argument Exercise
This basic exercise may help students begin to sort through their knowledge about their subject to identify the most important points their thesis should address. Although the final thesis will remove the first-person language like “I want to convince you that…”, many students will benefit from writing prompts that encourage them to think about their audience, their evidence and logic, and the long-term significance of their topic.
Dear Audience: I want to convince you that…
The main reasons you should believe me are…
(summary of your evidence and logic)
You should care about my thesis because…
(Consequences: why is it significant, what “lessons” are learned, so what?) |
From the late 1990s through nearly the entire decade that followed, Australia, already a dry place, suffered drought. Short of water and facing the prospect of long-term catastrophe, it embarked on building six major desalination plants.
Powering these plants could have led to a spike in carbon emissions, especially since Australia had long relied on coal for electricity. But according to the National Centre for Excellence in Desalination Australia (NCEDA), that hasn’t happened. Instead, desalination has actually spurred a turn toward renewables in Australia, as water utilities purchased wind energy to offset the power use of all six of the seawater desalination plants.
But even that doesn’t tell the whole of the story on how Australia has and continues to pursue potable water without wrecking Earth. Wind remains in the picture, but a wide range of other projects have been completed, are in the works or are being planned.
Some of these are big projects: In Western Australia, one of the country’s largest solar power stations is going up to supply 10 percent of the energy the Southern Seawater Desalination Plant uses. But NCEDA, with a mandate from the government to “efficiently and affordably reduce the carbon footprint of desalination facilities and technologies” is backing smaller initiatives, as well.
The organization says a remote indigenous community with “a limited brackish water supply” is developing “solar powered vacuum assisted membrane distillation to take hypersaline water and produce fresh water to blend with the brackish source.” This could make a reliable supply of water that meets national guidelines available to the community for the first time.
There’s another project in development that will use waste heat from a mineral processing plant to power a distillation system. “Upon successful completion and development, this will not only supply fresh water to the process and reduce dependence on the environment, but a potential excess wastewater balance will be eliminated,” NCEDA said.
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Mar. 16, 2001 Planetary scientists at Washington University in St. Louis and various collaborators have concluded that the Tharsis rise in Mars' Western Hemisphere is key to many of the Red Planet's mysteries, including its large-scale shape and gravity field, and its early climate and water distribution. Roger J. Phillips, Ph.D., Professor of Earth and Planetary Sciences, and Director of the McDonnell Center for the Space Sciences, and his colleagues suggest that an enormous load of volcanic material emplaced at the Tharsis rise caused global changes to the planet's outer strong layer, or lithosphere, creating many key features in the landscape. Two major ones, the Tharsis trough, surrounding Tharsis, and the Arabia bulge, on the planet's opposite side, are the result of this deformation. These features, in turn, are essential in the development of the Martian valley networks, the most common type of drainage system on Mars. Additionally, water and carbon dioxide released by Tharsis volcanism may have created an atmospheric greenhouse sufficient to warm the surface to above freezing, thus enabling running water to form the valleys.
The research was published as part of the March 16, 2001 issue of Science magazine.
The Tharsis rise dominates the western hemisphere of Mars. It is a broad, elevated region rising up to 10 kilometers above its surroundings and encompassing over 30 million square kilometers. The rise is the site of large-scale volcanism and extensive fracturing of the crust. Phillips and colleagues analyzed gravity and topography fields obtained from the Mars Global Surveyor spacecraft and compared them to a model of how these fields would behave when the heavy Tharsis volcanic load is dumped onto the spherical lithospheric shell.
"Imagine that Mars is a beach ball and that the Tharsis load is your fist," Phillips said. "As your fist pushes into the beach ball, there is a bulge created on the opposite side of the ball, and a depression or trough surrounds your fist. It is that simple."
The model correctly predicts many of Mars' broad-scale gravity and topography features. The researchers believe that these features were in place at the end of Mars' oldest time period, the Noachian epoch. This period extends back to near the planet's origin, estimated at about 4.6 billion years ago, and it ended between 3.8 and 3.5 billion years ago.
According to Phillips, the Tharsis magmas could have produced enough carbon dioxide and water to induce a climate that was sufficiently warm for liquid water to be stable on the planet's surface. "The total release of gases from Tharsis magmas could produce the integrated equivalent of a 1.5-bar carbon dioxide atmosphere and a global layer of water that is 120- meters thick," Phillips reported. "Much of the water would have been lost to space, but even so, these quantities of volatiles are sufficient to warm the atmosphere to the point at which the surface temperature is above freezing. The accumulation of atmospheric carbon dioxide from Tharsis may have made the latter part of the Noachian the most favorable time for this condition."
The researchers said that the development of the Tharsis trough and Arabia bulge was a major influence on the location and orientation of Martian valley networks and outflow channels. They pointed out that nearly all of the large Martian outflow channels originate in or flow into the Tharsis trough. The model tested the role of Tharsis loading in valley network orientations and the researchers concluded that many of these systems, similar to Earth's river systems, had to have formed after a "significant fraction" of the Tharsis load was in place. This is because the valleys follow the downhill direction of the topography induced by the deformation of Mars in response to the Tharsis load. As these valleys were formed near the end of the construction of Tharsis, in the latter part of the Noachian epoch, they may reflect the clement conditions induced by large amounts of atmospheric carbon dioxide that accumulated from the volcanism that developed Tharsis.
At the very end of the Noachian epoch, volcanism declined and carbon dioxide and water were removed from the atmosphere by a combination of factors, including stripping by the solar wind and thermal escape, among others. The removal of carbon dioxide and water would have driven surface temperatures below freezing, and Phillips estimates that this could have occurred in less than a few hundred million years. The preceding few hundred millions years, in the latter part of the Noachian, could well be considered Mars' "brief, shining moment."
"It is possible that during the Noachian Epoch, the structural and volcanic events associated with Tharsis evolution were the sine qua non that linked fluvial, geodynamical and climate activity on Mars, " Phillips concluded.
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The above story is reprinted from materials provided by Washington University In St. Louis.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Note: If no author is given, the source is cited instead. |
Science & Technology - Posted by Paul Mannion-Sheffield on Friday, March 9, 2012 11:49 - 2 Comments
Ultra high-res images with no-lens microscope
U. SHEFFIELD (UK) — A new electron microscope that works without a lens may create the highest resolution images ever seen.
Transmission electron microscopy (TEM), which looks through an object to see atomic features within it, has been constrained for over 70 years by the relatively poor lenses that are used to form the image.
The new method—called electron ptychography—dispenses with the lens and instead forms the image by reconstructing the scattered electron-waves after they have passed through the sample using computers.
Straight from the Source
Scientists at the University of Sheffield who consider their findings to be a first step in a “completely new epoch of electron imaging,” say the process has no fundamental experimental boundaries and could transform sub-atomic scale transmission imaging.
“To understand how material behaves, we need to know exactly where the atoms are. This approach will enable us to look at how atoms sit next to one another in a solid object as if we’re holding them in our hands,” says project leader John Rodenburg, professor in the department of electronic and electrical engineering.
“We’ve shown we can improve upon the resolution limit of an electron lens by a factor of five. An extension of the same method should reach the highest resolution transmission image ever obtained; about one tenth of an atomic diameter. No longer does TEM have to be bound by the paradigm of the lens, its Achilles’ heel since its invention in 1933.”
The technique, described in the journal Nature Communications, is applicable to microscopes using any type of wave and has other key advantages over conventional methods. For example, when used with visible light, the new technology forms a type of image that means scientists can see living cells very clearly without the need to stain them, a process which usually kills the cells.
The new method also disposes of the need to put a lens very close to a living sample, meaning that cells can be seen through thick containers like petri dishes or flasks. This means that as they develop and grow over days or weeks, they don’t have to be disturbed.
Plans are being put into place with the European Space Agency to take the new, more robust, microscope technology to the moon in 2018 to examine the structure of moon soil.
“We measure diffraction patterns rather than images. What we record is equivalent to the strength of the electron, X-ray or light waves which have been scattered by the object—this is called their intensity. However, to make an image, we need to know when the peaks and troughs of the waves arrive at the detector—this is called their phase.
“The key breakthrough has been to develop a way to calculate the phase of the waves from their intensity alone. Once we have this, we can work out backwards what the waves were scattered from: that is, we can form an aberration-free image of the object, which is much better than can be achieved with a normal lens.
“A typical electron or X-ray microscope image is about one hundred times more blurred than the theoretical limit defined by the wavelength. In this project, the eventual aim is to get the best-ever pictures of individual atoms in any structure seen within a three-dimensional object.”
The ground-breaking results were part of a three-year study costing £4.3 million which was funded by the Engineering and Physical Sciences Research Council (EPSRC).
The investigation was carried out with the help of Phase Focus Ltd, a University of Sheffield spin-out company, and Gatan Inc.
More news from University of Sheffield: www.shef.ac.uk/mediacentre/ |
Each generation of landing technology addresses the challenges posed by the previous generation.
People have been fascinated with the idea of exploring Mars since the very beginning of the space age. Largely because of the belief that some form of life may have existed there at one time, surface exploration has been the ultimate ambition of this exploration. Unfortunately, engineers and scientists discovered early on that landing a spacecraft on the surface of Mars would be one of the most difficult and treacherous challenges of robotic space exploration.
Upon arrival at Mars, a spacecraft is traveling at velocities of 4 to 7 kilometers per second (km/s). For a lander to deliver its payload to the surface, 100 percent of this kinetic energy must be safely removed. Fortunately, Mars has an atmosphere substantial enough for the combination of a high-drag heat shield and a parachute to remove 99 percent and 0.98 percent respectively of the kinetic energy. Unfortunately, the Martian atmosphere is not substantial enough to bring a lander to a safe touchdown. This means that an additional landing system is necessary to remove the remaining kinetic energy.
On previous successful missions, the landing system consisted of two major elements, a propulsion subsystem to remove an additional 0.002 percent (~50 to 100 meters per second [m/s]) of the original kinetic energy and a dedicated touchdown system. The first-generation Mars landers used legs to accomplish touchdown. The second generation of touchdown systems used air bags to mitigate the last few meters per second of residual velocity. The National Aeronautics and Space Administration (NASA) is currently developing a third-generation landing system in an effort to reduce cost, mass, and risk while simultaneously improving performance as measured by payload fraction to the surface and the roughness of accessible terrain.
Legged Landing Systems
The legs of the 1976 Viking mission lander represent the first-generation landing system technology (Pohlen et al., 1977). Basic landing-leg technology was developed for the lunar Surveyor and Apollo programs in the early 1960s. In conjunction with a variable-thrust liquid propulsion system and a closed-loop guidance and control system, legs represented an elegant solution to the touchdown problem. They are simple, reliable mechanisms that can be added to an integrated structure that houses the scientific and engineering subsystems for a typical surface mission.
The first challenge for a legged system is to enable the lander to touch down safely in regions with rocks. For this the legs must either be long enough to raise the belly of the lander above the rocks, or the belly of the lander must be made strong enough to withstand contact with the rocks. Neither solution is attractive. Either the lander becomes top heavy and incapable of landing on sloped terrain or a significant amount of structural reinforcement must be carried along for the remote chance that the lander will directly strike a rock. The decreased stability because of the high center of mass is exacerbated if a mission carries a large rover to the surface. Because of the rover's configurational requirements, it is typically placed on top of the lander. The Soviet Lunokhod lunar landers are an excellent example of this type of configuration.
A second major challenge of the legged-landing architecture is ensuring safe engine cutoff. To prevent the guidance and control system from inadvertently destabilizing the lander during touchdown, contact sensors have been used to shut down the propulsion system at the moment of first contact. On sloped terrain, this causes the lander to free fall the remaining distance, which can significantly increase the total kinetic energy present at touchdown and, in turn, decrease landing stability and increase mission risk. Implementation and testing of fault protection for engine cutoff logic has been, and continues to be, a difficult problem.
The first in-flight problem associated with engine shut off occurred on the lunar Surveyor lander mission when the propulsion system failed to shut off at touchdown, resulting in a significant amount of postimpact hopping. Fortunately, the terrain was benign, and the problem was not catastrophic. The second in-flight problem occurred on the Mars 98 lander mission when the engines were inadvertently shut off prematurely because of a spurious contact signal generated by the landing gear during its initial deployment. This problem resulted in a catastrophic loss of the vehicle. As a result, the Apollo missions all reverted to a man in the loop to perform engine shut off.
A third major challenge with a legged landing system for missions with rovers is rover egress. Once the lander has come to rest on the surface, the rover must be brought to the surface. For legged landers, a ramped egress system is the most logical configuration. Because rovers are bidirectional, the most viable arrangement has been considered two ramps, one at the front and one at the rear of the lander. The Soviet Lunokhod missions landed in relatively benign terrain, and in all cases, both ramps were able to provide safe paths for the rover. In the Mars Pathfinder mission, one of the two ramps was not able to provide a safe egress path for the Sojourner rover, but the second ramp did provide safe egress. For vehicles designed to explore a larger fraction of the Martian surface and, therefore, land in more diverse terrain, combinations of slopes and rocks could conceivably obstruct or render useless the two primary egress paths.
Air-Bag Landing Systems
The second-generation landing system was developed for the Mars Pathfinder mission and subsequently improved upon for the Mars Exploration Rover (MER) missions. These second-generation systems have a combination of fixed-thrust solid rocket motors and air bags to perform the touchdown task. The solid rocket motors, which are ignited two to three seconds prior to impacting the surface, slow the lander down to a stop 10 meters above the surface, from an initial velocity of approximately 120 meters/second. The lander is then cut away from the over-slung rockets and free falls for the remaining distance.
The air-bag system, which was developed to reduce cost and increase landing robustness, is designed to provide omnidirectional protection of the payload by bouncing over rocks and other surface hazards. Because the system can also right itself from any orientation, the challenge of stability during landing has been completely eliminated. Because the lander comes to rest prior to righting itself, the challenge of rock strikes has been reduced to strikes associated with the righting maneuver, which are significantly more benign. The challenge of thrust termination, in this case cutting the lander away from the rockets, remains but has been decoupled from the problem of landing stability. The problems of rover egress were addressed systematically on the MER missions; a triple ramp-like system provided egress paths in any direction, 360 degrees around the lander.
Although the air-bag landing system has addressed some of the challenges and limitations of legged landers, it has also introduced some challenges of its own. Horizontal velocity control using solid rockets and air-bag testing were significant challenges for both the Mars Pathfinder and MER missions.
The Sky-Crane Landing System
As Mars surface explorations mature, roving is becoming more important in the proposed mission architectures. The MER missions demonstrated the value of a fully functional rover not reliant on the lander to complete its surface mission. In the 2009 Mars Science Laboratory (MSL) and other future missions, the rover's capabilities and longevity will be extended. Future missions are also being designed to access larger areas of the planet and, therefore, will require more robust landing systems that are tolerant to slope and rock combinations that were previously considered too hazardous to land or drive on. The third-generation landing system, the sky-crane landing system (SLS), currently being developed for the MSL mission, will directly address all of the major challenges presented by the first- and second-generation landing systems. It will also eliminate the problem of rover egress.
SLS eliminates the dedicated touchdown system and lands the fully deployed rover directly on the surface of Mars, wheels first. This is possible because the rover is no longer placed on top of the lander. In the SLS, the propulsion module is above the rover, so the rover can be lowered on a bridle, similar to the way a cargo helicopter delivers underslung payloads.
The landing sequence for future missions will be similar to the Viking mission, except for the last several seconds when the sky-crane maneuver is performed. After separating from the parachute, the SLS follows a Viking-lander-like propulsive descent profile in a one-body mode from 1,000 meters above the surface down to approximately 35 meters above the surface. During this time, a throttleable liquid-propulsion system coupled with an active guidance and control system controls the velocity and position of the vehicle. At 35 meters, the sky-crane landing maneuver is initiated, and the rover is separated from the propulsion module. The rover is lowered several meters as the entire system continues to descend. The two-body system then descends the final few meters to set the rover onto the surface and cut it away from the propulsion module. The propulsion module then performs an autonomous fly-away maneuver and lands 500 to 1,000 meters away.
The central feature of the SLS architecture is that the propulsion hardware and terrain sensors are placed high above the rover during touchdown. As a result, their operation is uninterrupted during the entire landing sequence. One important result of this feature is that the velocity control of the whole system is improved, and, therefore, the rover touches down at lower velocity. Thus, there is no last-meter free fall associated with engine cutoff, and, because dust kick-up is minimal, the radar antennas can continue to operate even while the rover is being set down on the surface.
The lower impact velocity has two effects. First, the touchdown velocities can now be reliably brought down to the levels the rover has already been designed for so it can traverse the Martian surface. Second, the low velocity, coupled with the presence of bridles until the rover's full weight has been transferred to the surface, results in much more stability during landing.
Because the rover does not have to be protected from the impact energy at landing and because there is no need to augment stability at landing, there is no longer a need for a dedicated touchdown system. This, in turn, eliminates the need for a dedicated egress system. The SLS takes advantage of the fact that the rover's mobility system is inherently designed to interact with rough, sloping natural terrain. Rovers are designed to have high ground clearance, high static stability, reinforced belly pans, and passive terrain adaptability/conformability. These are all features of an ideal touchdown system.
Touchdown sensing can be done in several ways. The simplest and most robust way is to use a logic routine that monitors the commanded up-force generated by the guidance and control computer. The landing sequence is specifically designed to provide a constant descent velocity of approximately 0.75 m/s until touchdown has been declared. Prior to surface contact, the commanded up-force is equal to the mass of the rover plus the mass of the descent stage (which are roughly equal) times the gravity of Mars. During the touchdown event, the commanded up-force fluctuates depending on the specific geometry of the terrain.
Once the weight of the rover has been fully transferred to the surface of Mars, the commanded up-force takes on a new steady-state value equal to the mass of the descent stage times the gravity of Mars, approximately one-half of its pretouchdown magnitude. The system declares touchdown after the new lower commanded up-force has lasted for at least 1.5 seconds. This approach provides an unambiguous touchdown signature without the use of dedicated sensors.
The fly-away phase of the landing sequence is initiated when touchdown has been declared. During the fly-away phase, separation of the rover is accomplished by the pyrotechnic cutting of the bridle and umbilical lines connecting the rover and descent stage. The descent stage then uses its onboard computer to guide the propulsion module up and away from the rover and land it several hundred meters away.
As Mars explorers have learned the hard way, it's not typically the fall that kills you, it's the landing. Landing technology has matured significantly in the 40 years since NASA began exploring extraterrestrial surfaces. Each generation of landing technology has attempted to resolve the challenges posed by the previous generation. The SLS represents the latest stage in that evolution.
The research described in this paper was carried out at the Jet Propulsion Laboratory of the California Institute of Technology under a contract with the National Aeronautics and Space Administration.
From The Bridge, Volume 34, Number 4 - Winter 2004
Pohlen, J., B. Maytum, I. Ramsey, and U.J. Blanchard. 1977. The Evolution of the Viking Landing Gear. JPL Technical Memorandum 33-777. Pasadena, Calif.: Jet Propulsion Laboratory. |
Transcription is the process by which the genetic information in DNA is converted into RNA. The mechanism of transcription can be described simply in 6 steps (5 in prokaryotes):
- The section of DNA to be transcribed is recognized by proteins involved in transcription.
- Hydrogen bonds between base pairs of DNA are broken and the DNA double helix "unzips."
- Complimentary RNA bases bind to the now exposed DNA bases
- RNA Polymerase binds the RNA bases together to form a strand of mRNA
- Hydrogen bonds formed between the original DNA strand and the new RNA strand are broken
- in eukaryotes, the new RNA strand is further processed and moves to the cytoplasm.
The segment of DNA to be transcribed is called a transcription unit, and contains at least one gene. If this gene codes for a protein, the RNA transcription product is called Messenger RNA, or mRNA. The gene may also code for Rybosomal RNA (rRNA), transfer RNA (tRNA), or a ribozyme.Last modified on 11 January 2011, at 13:34 |
Classical Era Music Versus Classical Music
The term “classical music” has become something of a misnomer, used to describe virtually any music that was not written within the last fifty years. This can be quite misleading, as the term “Classical Music” is actually used to describe a very specific time period in music history. Most importantly, the term refers to stylistic features that are unique to the Classical music era.
#1. Brief (very brief!) history:
The Classical era in music occurred between ~ 1730 and 1820. These dates are inexact, because composers created music that was stylistically classical both before and after these dates. In Europe at the time, art, architecture, dance, and music were all experiencing a fundamental change from the stylistic features of the Baroque period which preceded the Classical period. Many of these changes were inspired by changes in the social, and economic fabric of Western Europe at the time;
#2. Stylistic features:
Music composed in the classical period share many common stylistic traits. Stylistic trends of classical music include cleaner, simpler music, a stark contrast to the intricate ornamentation of the Baroque period, homophonic music (melody over accompanying chords), and increasing dynamic contrast and range. As well, orchestral instrumention became standardized, and instrumental music became increasingly important.
#3. Notable classical composers:
While there were numerous composers composing wonderful music in the classical period, there are several whose musical works were so notable that they defined the Classical music era.
Haydn: An Austrian composer who was an especially important composer in the areas of symphonic music, and the evolution of the string quartet. He was a very prolific composer, and played an important part in developing the sonata style which became a hallmark of Classical era music.
Mozart: One of the most infamous composers in history, Mozart had a very short life, dying at the age of 35. Despite his short life, Mozart composed over 600 works, and was most noted for his symphonic music, concertos, and his contributions to opera buffa.
Schubert:Schubert was another short lived composer; he died at the age of 32. He too was prolific, but unlike Mozart and Haydn, the bulk of Schubert’s compositions were vocal works. Of principal importance were his lieder (art songs). Schubert is also a transitional composer; many of his later works began to demonstrate stylistic features found most commonly in Romantic era music.
Beethoven:Probably one of the most famous composers in history, Beethoven is another transitional composer. His early works were heavily influenced by Mozart, but his later works moved towards stylistic trends found in Romantic era music. Most notable, despite losing his hearing beginning at age 26, Beethoven continued to compose, and perform, even when the hearing loss became profound.
Did you learn anything new about Classical era music? Who is your favourite Classical era composer? Tell us in the comments below! |
Bronchitis is an infection or inflammation of the large air passages to the lungs. (These airways are called bronchi.) When your child has a cold, sore throat, flu, or sinus infection, the virus that caused the misery can spread to the bronchi. Once the germs take hold there, the airways become swollen, inflamed, and partly blocked with mucus.
While bacterial infections and irritants such as cigarette smoke, fumes, and dust can also trigger bronchitis, viruses are the most common culprits in children.
Your preschooler may first have cold symptoms, like a sore throat, fatigue, runny nose, chills, aches, and a slight fever (100 to 101 degrees F). He'll develop a cough, which often starts out dry and unproductive but winds up producing greenish or yellowish mucus. He may gag or vomit while coughing.
Your child's chest may hurt, he may feel short of breath, and he may wheeze. If the bronchitis is severe, his fever may climb for a few days, and his cough may linger for several weeks as the bronchi heal.
Some people — almost always adults who smoke or children who live with smokers — suffer from bronchitis symptoms for months at a time. This is called chronic bronchitis (as opposed to infectious or acute bronchitis), and it's one excellent reason to keep cigarettes out of your house.
Because the condition is almost always viral, there really isn't much your doctor can do for a child with bronchitis, but call her if you'd like a diagnosis or some reassurance.
Do let her know if your preschooler's cough is getting worse after the first few days or so, or if he has a fever for more than a few days, or if his fever tops 103 degrees F. Also call if your child is wheezing in addition to coughing or if he's coughing up blood.
Of course, if your child is struggling to breathe, you should call 911. |
This page is a stub for educational material on counting with a target audience of K-8 (age 5-13).
Counting and the Organization of the number system
Making connections between and number names and the concept of quantity. This can be taught by tagging or touching an item while saying the number word it goes with, for example, saying the word "One" while touching a singular item, let's say a cube, next saying "two" while touching two cubes. By changing the items they are counting with, the student will gain understanding that it is not the item they are touching with the name "one" but the amount of items they are touching, and it is the concept of "one" that they are naming.
Unitizing is the ability to think about the exact number in a group of things while also thinking about how many groups of things there are simultaneously. This is best exemplified when counting groups of things, such as, a group of ten cubes. Depending on how the student is able to arrive at the total number, they will either be adding, multiplying or dividing. The example below is a potential dialogue between a teacher and student.
- "Sam has one group of ten cubes. How many cubes does Sam have?" (10 cubes) - in this example, if the student tags each cube as he/she counts this is adding (1 + 1 + 1 + 1 and so on) if the student is able to conceptualize that one group of ten or (1 x 10) they are multiplying.
- "Now Sam has two groups of ten cubes. Now how many cubes does Sam have? (20 cubes) - similarly to above, if the student tags each cubes as he/she counts this is adding, if they can conceptualize that 2 groups of ten or (2 x 10) to arrive at the answer, and are able to skip count from ten to twenty, they are multiplying.
- "If Sam has 30 cubes, each in groups of ten. How many groups does Sam have?" - in this example, if the student begins by grouping the loose cubes into groups of then and then counts the number of groups, they are using adding to attain the answer. If they student is able to conceptualize that thirty cubes could be grouped into three equal groups, they are dividing. |
| Keep it Up!
||Additional Activity #1
Students strive to keep a ball in the air while naming healthy foods.
Students will identify a variety of healthy foods.
||One volleyball or beach ball for every group of four to five students
- Divide the class into four or five groups.
- Tell them you are going to review some healthy foods from all five food groupings (milk and milk products; fruits; vegetables; grains; meats, beans, and nuts).
- Remind them foods are divided into groups because each group provides our body with different, essential nutrients such as milk and milk products which provide calcium. Calcium keeps our bones healthy.
- Give each group a ball. Have them choose a number between one and fifteen.
- Explain that students are to keep the ball in the air using that number of strikes, taps, or bumps. For example if the group chose the number ten, they must keep the ball in the air for ten strikes, taps, or bumps.
- If the ball drops, they should start over. When they reach their chosen number, the next student to touch the ball should hold it and state one delicious healthy food and then pass the ball to their right.
- The next student should then name a healthy food and so on until they have gone all the way around the circle.
- If a student names a food or drink high in fat or added sugar, gently guide him or her to come up with a healthier choice.
- Once each student has named a healthy food the group should begin again.
- If time permits, ask a few students to share some healthy foods with the class.
Although all foods can fit into a healthy eating plan in moderation, it is important to reinforce that healthier foods give the body more energy to play and grow. "Junk foods" (processed foods high in fat and added sugar), contain a significant amount of calories but add very little nutrition to kidsí diets.
"Energy"/"Go" foods refer to nutritious foods which give the body the energy to go and grow. "Empty"/"Slow" foods refer to foods high in fat and added sugar which can slow the body down.
Healthy ("Energy"/"Go") Snack Foods/Drinks:
||whole grain bread
||baked tortilla chips with salsa
||air popped popcorn (without butter)
||low-sugar granola bars
||whole wheat pizza
||low-fat trail mix
||peanut butter crackers
||100% fruit juice
||skim or low-fat milk
||natural fruit smoothies
Less Healthy ("Empty"/"Slow") Snack Foods/Drinks:
||white bread and rolls
||cookies (e.g. Oreos)
||candy (e.g. Skittles)
||high-sugar juice (e.g. Kool-Aid)
Related National Standards
||1.8.1, 1.8.2, 1.8.7, 5.8.4, 5.8.6, 7.8.1, 7.8.2, 7.8.3
Further information about the National Standards can be found here |
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in Data Studio
from datasets import load_dataset
faq = load_dataset(
"styal/filtered-finephrase-faq",
split="train[:50%]",
)
tutorial = load_dataset(
"styal/filtered-finephrase-tutorial",
split="train[:50%]",
)
table = load_dataset(
"styal/filtered-finephrase-table",
split="train[:50%]",
)
math = load_dataset(
"styal/filtered-finephrase-math",
split="train[:40%]",
)
py = load_dataset(
"styal/filtered-python-edu.eng",
split="train[:20%]",
)
faq = faq.remove_columns([col for col in faq.column_names if col != "text"])
math = math.remove_columns([col for col in math.column_names if col != "text"])
table = table.remove_columns([col for col in table.column_names if col != "text"])
tutorial = tutorial.remove_columns([col for col in tutorial.column_names if col != "text"])
py = py.remove_columns([col for col in py.column_names if col != "text"])
from datasets import concatenate_datasets
merged = concatenate_datasets([faq, math, table, py, tutorial])
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