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7月6日 Scientists Identify the Brain’s Activity HubThe brain is the control center of the central nervous system, responsible for behavior. In mammals, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, equilibrioception, sense of taste, and olfaction. The outer layer of the brain, the reasoning, planning and self-aware region known as the cerebral cortex, has a central clearinghouse of activity below the crown of the head that is widely connected to more-specialized regions in a large network similar to a subway map, scientists reported. The new report, published in the free-access online journal PLOS Biology, provides the most complete rough draft to date of the cortex’s electrical architecture, the cluster of interconnected nodes and hubs that help guide thinking and behavior. The paper also provides a striking demonstration of how new imaging techniques focused on the brain’s white matter — the connections between cells, rather than the neurons themselves — are filling in a dimension of human brain function that has been all but dark. In previous studies, scientists have used magnetic resonance imaging to identify peaks and valleys of neural activity when people are doing various things, like making decisions, reacting to frightening images or reliving painful memories. But these studies, while provocative, revealed virtually nothing about the underlying neural networks involved — about which brain regions speak to one another and when. Previous estimates of network structure, based on such imaging, have been sketchy. The new findings, while not conclusive, give scientists what is essentially a wiring diagram that they can test and refine. “This is just about the coolest paper I’ve seen in a long time, and forward-looking in terms of where the science is going,” said Dr. Marcus E. Raichle, a professor of neurology and radiology at Washington University in St. Louis, who was not involved in the research. He added, “They’ve found in the brain what looks like a hub map of the airline system for the United States.” Dr. Sporns said continued research should help produce a complete and detailed neural wiring diagram, what he called the “connectome” of the brain. “We hope we can get to a place where we have, in effect, a brain simulator, in the same way we have computer models that can simulate the climate,” he said, “so we can simulate activation patterns we see in clinical cases,” like psychiatric problems and brain injuries. For more details on Scientists Identify the Brain’s Activity Hub visit www.halfvalue.com and www.halfvalue.co.uk For more information on books visit www.Lookbookstores.com 7月9日 Nasa will send ‘icebreaker’ to Mars in hunt for lifeAspace probe designed to look for signs of life in the oceans that once covered Mars will be unveiled by Nasa scientists this week. The Phoenix Mars Lander will be sent to the icy wastelands near the red planet’s north polar ice cap. It will be launched next month and is expected to reach the planet in May.
When the probe lands its task will be to dig deep into the soil, scoop out chunks of ice and analyze them for signs of past or present life forms. The landing site has been chosen as the most likely point to find buried ice that once formed part of the planet’s oceans.
“The arctic plains are the right place for the next step in Mars exploration and this is the right time to go there,” said Leslie Tamppari, Phoenix project scientist at Nasa’s Jet Propulsion Laboratory. “We expect to touch Martian ice for the first time.”
Mars is now a cold desert planet with the thinnest of atmospheres and no water on the surface. However, previous missions have shown that there are large amounts of ice below the planet’s crust in the northern arctic plains. read more...
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Eris, discovered in 2005 and named for an ancient Greek goddess of strife and discord, is 27% more massive than Pluto, they found. Eris is about half the size of Earth’s moon, Brown said. Pluto, named for the ancient Greek god of the underworld, was discovered in 1930. It was considered our solar system’s ninth planet until August 2006, when the International Astronomical Union declared it a dwarf planet, a term referring to lesser, round solar system bodies orbiting the sun, mostly in an outer region called the Kuiper belt. “I don’t think we’re picking on Pluto,” Brown, a professor of planetary astronomy who helped provoke the demotion of Pluto, said in a telephone interview “It’s just the truth. It (Eris) just is more massive than Pluto. It’s just the way it is,” Brown said. The findings were published in the journal Science. Scientists previously had figured that Eris’s diameter was bigger than Pluto’s but did not know about its mass. Like Pluto, Eris is unlikely to become a holiday destination. Both inhabit a remote and frigid region of the solar system. The new data indicated Eris likely is composed of ice and rock, very similar to Pluto. “It is covered in an almost perfectly uniform white frost. So it looks just like a white billiard ball out there,” Brown said Pluto and Eris both follow elliptical rather than circular orbits as they journey around the Sun. Eris’s orbit is highly elongated and takes 560 years. It ventures anywhere from 3.5 billion miles to 10 billion miles from Earth, Brown said. Pluto, whose 250-year orbit on occasion brings it inside the orbit of the outermost planet Neptune, journeys as far as 5 billion miles from Earth, Brown said. Eris, which has a small moon, has a diameter of 1,500 miles, just bigger than Pluto’s 1,400 miles. Brown said there are roughly 50 known objects in the solar system that can be classified as dwarf planets, including some close in size to Eris and Pluto. Brown said Pluto should be getting accustomed to second place For more details on Pluto’s not biggest dwarf visit www.halfvalue.com and www.halfvalue.co.uk 6月12日 And found: 24 new wild speciesA FROG with fluorescent purple markings and 12 kinds of dung beetles are among two dozen new species discovered in the remote plateaus of eastern Suriname, scientists said. The expedition was sponsored by two mining companies hoping to excavate the area for bauxite, the raw material used to make aluminum, and it was unknown how the findings would affect their plans
Scientists discovered the species during a 2005 expedition led by the US-based nonprofit Conservation International in rainforests and swamps about 130 km southeast of Paramaribo, the capital of the South American country, organisation spokesman Tom Cohen said.
Among the species found were the atelopus frog, which has distinctive purple markings; six types of fish; 12 dung beetles, and one ant species, he said. The scientists called for better conservation management in the unprotected, stateowned areas, where hunting and small-scale illegal mining is common.
The study was financed by Suriname Aluminum Company LLC and BHP Bniton Maatschappij Suriname. Suriname Aluminum, which has a government concession to explore gold in the area, will include the data in its environmental assessment study, said Haydi Berrenstein, a Conservation International ofIicial in Suriname, which borders Brazil, Guyana and French Guiana. About 80 per cent of Suriname is covered with dense rainforest. read more....
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For more information on books visit www.Lookbookstores.com 6月8日 The Global warmingGlobal warming is the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation. Global average air temperature near the Earth's surface rose 0.74 ± 0.18 °C during the past century. The Intergovernmental Panel on Climate Change (IPCC) concludes, "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations," which leads to warming of the surface and lower atmosphere by increasing the greenhouse effect. Natural phenomena such as solar variation combined with volcanoes have probably had a small warming effect from pre-industrial times to 1950, but a small cooling effect since 1950.
These basic conclusions have been endorsed by at least 30 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries. The American Association of Petroleum Geologists is the only scientific society that rejects these conclusions, and a few individual scientists also disagree with parts of them.
An increase in global temperatures can in turn cause other changes, including sea level rise, and changes in the amount and pattern of precipitation resulting in floods and drought. There may also be changes in the frequency and intensity of extreme weather events, though it is difficult to connect specific events to global warming. Other effects may include changes in agricultural yields, glacier retreat, reduced summer streamflows, species extinctions and increases in the ranges of disease vectors.
The term "global warming" is a specific example of the broader term climate change, which can also refer to global cooling. In common usage the term refers to recent warming and implies a human influence. The United Nations Framework Convention on Climate Change (UNFCCC) uses the term "climate change" for human-caused change, and "climate variability" for other changes. The term "anthropogenic climate change" is sometimes used when focusing on human-induced changes. read more……
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According to a theory, the Moon was created when a rock the size of Mars slammed into Earth, short ly after the solar system began forming about 4.5 billion years ago. Locked in orbit
Perhaps the coolest thing about the Moon is that it always shows us the same face. Since both the Earth and Moon are rotating and orbiting, how can this be? Long ago, the Earth's gravitational effects slowed the Moon's rotation about its axis. Once the rotation slowed enough to match its orbital period (the time it takes to go around Earth), the effect stabilised. Many of the moons around other planets behave similarly. What about phases?
Here's how they work: As the Moon orbits, it spends part of its time between us and the Sun, and the lighted half faces away from us. This is called a new Moon.Once it is opposite the Sun, it becomes fully lit from our view - a full Moon. Moon trees
More than 400 trees on Earth came from the Moon. They came from lunar orbit. In 1971, Apollo 14 astronaut Stuart Roosa took a bunch of seeds with him. Later, the seeds were germinated on Earth, planted at various sites around the US, and came to be called the Moon trees. Most of them are doing just fine. read more...... Find more about Moon visit www.halfvalue.com and www.halfvalue.co.uk For more details on Books at www.lookbookstores.com 5月9日 Biggest, brightest star explosionNASA ASTRONOMERS, reported the biggest and brightest star explosion ever recorded a blast whose light began reaching Earth in the past year from 240 million light-years away. The remnants of the explosion pose no threat to people or electronics, but it still offers hints of a future fireworks display from another, much closer star — a mere 7,500 light-years away — that has been on astronomers’ death-watch list for some time.
Nasa’s Chandra X-ray Observatory satellite images show the supernova, SN 2006gy, was a distant star about 150 times heavier than our sun when it exploded, said Chandra team leader Nathan Smith of the USbased University of CaliforniaBerkeley.
Supernovas - an exploding star - happen when enormous stars have exhausted their fuel and crumble under the weight of their own gravity. But the SN 2006gy's explosion was different, and could point to how the early stars in the universe ended their lives, spraying their innards across space.
SN 2006gy, which is about 240 million light years away, surprisingly continues to burn brightly more than 250 days after its initial explosion first attracted the astronomers’ attention. Most exploding stars wink out of sight a few months after their blast, said Mario Livio of the Space Telescope Science Institute in Baltimore, who was not part of the discovery team.
“Right now, (SN 2006gy) is as bright as the brightest star,” Smith said.
The luminosity of an exploding star drops quickly as the shock wave from a supernova burns through gas left over from the explosion.
The X-ray measurements made by Chandra suggested a new theory: radioactive elements created in the blast are burning away steadily.
The team is continuing to track the supernova, to see whether it continues to burn.
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For more details on Books at www.lookbookstores.com 4月13日 What is Weather forecasting?Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Humankind has attempted to predict the weather since ancient times. Today, weather forecasts are made by collecting quantitative data about the current state of the atmosphere and using scientific understanding of atmospheric processes to project how the atmosphere will evolve.
For millennia people have tried to forecast the weather. In 650 BC, the Babylonians predicted the weather from cloud patterns. In about 340 BC, Aristotle described weather patterns in Meteorological. Chinese weather prediction lore extends at least as far back as 300 BC.
Weather forecasting is the application of science and technology to predict the state of the atmosphere at a future time. Prior to the advent of scientific methods of weather forecasting, a large body of weather folklore developed to explain the weather. An example is the Groundhog Day celebration near the end of winter in parts of the United States and Canada. Today, weather forecasts are made by collecting data that describe the current state of the atmosphere (particularly the temperature, humidity and wind) and using physically-based mathematical models to determine how the atmosphere is expected to change in the future. read more.......
For more details on Weather Forecasting visit www.halfvalue.com and www.halfvalue.co.uk For more information on books visit www.Lookbookstores.com 4月3日 What is Atomic Clock?An atomic clock is a type of clock that uses an atomic resonance frequency standard to feed its counter. Early atomic clocks were masers with attached equipment. Today's best atomic frequency standards (or clocks) are based on absorption spectroscopy of cold atoms in atomic fountains. National standards agencies maintain an accuracy of 10-9 seconds per day, and a precision equal to the frequency of the radio transmitter pumping the maser. The clocks maintain a continuous and stable time scale, International Atomic Time (TAI). For civil time, another time scale is disseminated, Coordinated Universal Time (UTC). UTC is derived from TAI, but synchronized with the passing of day and night based on astronomical observations.
The first atomic clock was built in 1949 at the U.S. National Bureau of Standards (NBS). The first accurate atomic clock, a cesium standard based on the transition of the cesium-133 atom, was built by Louis Essen in 1955 at the National Physical Laboratory in the UK. This led to the internationally agreed definition of the second being based on atomic time.
The best atomic clocks on Earth today are stable to about one part in 10^15," notes Kuzmich. That means an observer would have to watch the clock for 10^15 seconds or 30 million years to see it gain or lose a single second.read more....
For more details on Atomic Clock visit www.halfvalue.com and www.halfvalue.co.uk For more information on books visit www.Lookbookstores.com 8月24日 Lifeline of Earth: Ozone layerLifeline of Earth: Ozone layer The ozone layer, or ozonosphere layer (rarely used term), is that part of the Earth's atmosphere which contains relatively high concentrations of ozone (O3). "Relatively high" means a few parts per million - much higher than the concentrations in the lower atmosphere but still small compared to the main components of the atmosphere. Introduction of Ozone Layer The ozone layer is a region of concentration of the ozone (O3) molecule in the Earth's atmosphere. The layer sits at an altitude of about 10 to 50 kilometers, with a maximum concentration in the stratosphere at an altitude of approximately 25 kilometers. In recent years, scientists have measured a seasonal thinning of the ozone layer primarily at the South Pole. This phenomenon is being called the ozone hole. The ozone layer naturally shields Earth's life from the harmful effects of the sun's ultraviolet (UV) radiation. A severe decrease in the concentration of ozone in the ozone layer could lead to the following harmful effects:
Ozone is created naturally in the stratosphere by the combining of atomic oxygen (O) with molecular oxygen (O2). This process is activated by sunlight. Ozone is destroyed naturally by the absorption of ultraviolet radiation, O3 + UV >>> O2 + O, and by the collision of ozone with other atmospheric atoms and molecules. O3 + O >>> 2O2 O3 + O3 >>> 3O2 Ozone hole Technically, the term "ozone hole" should be applied to regions where stratospheric ozone depletion is so severe that levels fall below 200 Dobson Units (D.U.), the traditional measure of stratospheric ozone. Normal ozone concentration is about 300 to 350 D.U. Such ozone loss now occurs every springtime above Antarctica, and to a lesser extent the Arctic, where special meteorological conditions and very low air temperatures accelerate and enhance the destruction of ozone loss by man-made ozone depleting chemicals (ODCs). A common misconception is that there is an ozone hole above us in the sky which is letting in harmful ultraviolet (UV) radiation from the Sun. Ozone depletion, in fact, is occurring all over the world due to man-made pollution, at levels within the stratosphere, 19 to 30 km above the Earth's surface. However, in certain parts of the world, ozone depletion is particularly severe, and it is in the regions where the term "ozone hole" strictly applies. Every March to April during the Northern Hemisphere springtime similar, but less pronounced ozone hole forms above the Arctic. The natural circulation of wind - the polar vortex - which isolates Antarctica from the rest of the world during the Southern Hemisphere winter and early spring, contributing to the ozone loss there, is much less developed in the Northern Hemisphere above the Arctic. In addition, stratospheric temperatures there are not as low as in the Antarctic, and consequently the loss of ozone is not as severe. However, the formation of even a moderate ozone hole above the Arctic region can give cause for considerable concern due to the greater populations in the higher latitudes of the Northern Hemisphere. Problem with the ozone layer The ozone layer absorbs most of the ultraviolet radiaton coming from the sun and is very important for the survival of life on earth. Ozone is a gas composed of molecules of three oxygen atoms (O3). There is a layer of ozone in the stratosphere which is most dense between 20 and 25 km above the earth's surface. It is estimated by scientists that a one per cent decreases in ozone levels produces between one and two percent increase in ultraviolet radiation. The Melbourne Bureau of Meteorology has found that there has been an 8% increase in ultraviolet radiation during the summer since 1980. Ozone deplition The ozone layer can be depleted by free radical catalysts, including nitric oxide (NO), hydroxyl (OH), and atomic chlorine (Cl) and bromine (Br). While there are natural sources for all of these species, the concentrations of chlorine and bromine have increased markedly in recent years due to the release of large quantities of manmade organohalogen compounds, especially chlorofluorocarbons (CFCs) and bromofluorocarbons. These highly stable compounds are capable of surviving the rise to the stratosphere, where Cl and Br radicals are liberated by the action of ultraviolet light. Each radical is then free to initiate and catalyze a chain reaction capable of breaking down over 10000 ozone molecules. See more details click here |
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