Saturday, 29 December 2007

Koopman Collection

The Koopman Collection in the Koninklijke Bibliotheek, National Library of the Netherlands consists of over 8250 French works of literature in rare and deluxe editions, including dedication copies and artists' books, a series of manuscripts and archival documents. The The books are all listed in the KB online public catalogue and are available for reference in the Special Collections reading room. A provisional catalogue also exists in book form.
first donation for the collection dates from 1934. The collection was donated by Louis Koopman (1887-1968), in commemoration of his fiancée Anny Antoine (1897-1933) who died in an accident. Thanks to a legacy, the Anny Antoine/Louis Koopman Foundation, the collection can still be expanded with new acquisitions on a daily basis.
Léger, Matisse, Picasso, Braque, Colette, Cocteau, De Beauvoir, Duras, and many others… The Koopman Collection is a unique collection of French literary works of the 20th century in special editions.
A wide selection of artists' books, dedication copies and deluxe editions is highlighted in seven films on this webexhibition and in dozens of richly illustrated essays on books from the collection.
Link to the digital collection and to the web exhibition.

Sunday, 2 December 2007

Venus as a more Earth-like planet

Venus is Earth's near twin in mass and radius, and our nearest planetary neighbour, yet conditions there are very different in many respects. Its atmosphere, mostly composed of carbon dioxide, has a surface temperature and pressure far higher than those of Earth. Only traces of water are found, although it is likely that there was much more present in the past, possibly forming Earth-like oceans. Here we discuss how the first year of observations by Venus Express brings into focus the evolutionary paths by which the climates of two similar planets diverged from common beginnings to such extremes. These include a CO2-driven greenhouse effect, erosion of the atmosphere by solar particles and radiation, surface–atmosphere interactions, and atmospheric circulation regimes defined by differing planetary rotation rates.
The overall sense of the results from the first year of operation of Venus Express is that the differences, particularly in climate, between Venus and Earth are much less mysterious than previously thought after the early phase of spacecraft exploration. They are consistent with theoretical ideas and interpretations suggesting that the two planets had similar surface environments in the past and that they evolved differently, with Earth's oceans converting most of its atmospheric CO2 to carbonate rocks, and Venus losing most of its water to space. Both processes can now be seen to be still going on. The high zonal winds and near-equatorial turbulence on Venus, as well of course as the high surface temperatures, result from the depth of the atmosphere and huge inventory of greenhouse gas retained by Venus. The slow rotation of Venus, as well as possibly being responsible for the lack of magnetic field that makes erosion of the atmosphere by the solar wind so effective, permits the Earth-like Hadley cell component of the atmospheric circulation to extend closer to the poles, where it breaks down in spectacular fashion to form mid-latitude jets and polar vortices that are larger and more energetic than Earth's but are in many respects quite similar (Read more).

Monday, 19 November 2007

Flying Snake

The image of airborne snakes may seem like the stuff of nightmares (or a certain Hollywood movie), but in the jungles of South and Southeast Asia it is reality.Flying snake is a misnomer, since, barring a strong updraft, these animals can’t actually gain altitude. They’re gliders, using the speed of free fall and contortions of their bodies to catch the air and generate lift.Once thought to be more parachuters than gliders, recent scientific studies have revealed intricate details about how these limbless, tube-shaped creatures turn plummeting into piloting. To prepare for take-off, a flying snake will slither to the end of a branch, and dangle in a J shape. It propels itself from the branch with the lower half of its body, forms quickly into an S, and flattens to about twice its normal width, giving its normally round body a concave C shape which can trap air. By undulating back and forth, the snake can actually make turns. Flying snakes are technically better gliders than their more popular mammalian equivalents, the flying squirrels.There are five recognized species of flying snake, found from western India to the Indonesian archipelago. Knowledge of their behavior in the wild is limited, but they are thought to be highly arboreal, rarely descending from the canopy. The smallest species reach about 2 feet (61 centimeters) in length and the largest grow to 4 feet (1.2 meters).Their diets are variable depending on their range, but they are known to eat rodents, lizards, frogs, birds, and bats. They are mildly venomous snakes, but their tiny, fixed rear fangs make them harmless to humans.Scientists don’t know how often or exactly why flying snakes fly, but it’s likely they use their aerobatics to escape predators, to move from tree to tree without having to descend to the forest floor, and possibly even to hunt prey.One species, the twin-barred tree snake, is thought to be rare in its range, but flying snakes are otherwise quite abundant and have no special conservation status.

Thursday, 20 September 2007

Hafele-Keating experiment

During October, 1971, four cesium atomic beam clocks were flown on regularly scheduled commercial jet flights around the world twice, once eastward and once westward, to test Einstein's theory of relativity with macroscopic clocks. From the actual flight paths of each trip, the theory predicted that the flying clocks, compared with reference clocks at the U.S. Naval Observatory, should have lost 40+/-23 nanoseconds during the eastward trip and should have gained 275+/-21 nanoseconds during the westward trip ...
Relative to the atomic time scale of the U.S. Naval Observatory, the flying clocks lost 59+/-10 nanoseconds during the eastward trip and gained 273+/-7 nanosecond during the westward trip, where the errors are the corresponding standard deviations. These results provide an unambiguous empirical resolution of the famous clock "paradox" with macroscopic clocks.

Friday, 24 August 2007

Hall of Human Origins

All species consist of individuals that differ at some level. In Homo sapiens, population diversity arose as small groups occupied varied environments around the world. Localized populations changed due to genetic drift and natural selection. For example, some populations eventually showed more susceptibility to certain diseases, or more ability to digest certain foods. Superficial differences in stature and hair, eye, and skin color also arose among individuals and populations.Although these population changes take place at a genetic level, it does not mean that genes define "race." Race is cultural and social, not biological.Small, isolated groups are less and less prevalent in the human population. Our population is now abundant, consisting of larger, varied groups that intermingle and overlap. Since humans reproduce both within and between groups, we constantly mix genetic information. As a result, genetic differences between people of the same "racial" group can be greater than the those between people of two different groups. Furthermore, influences other than genes—such as hormones and environmental factors—also contribute to individual variation (go).

Tuesday, 21 August 2007

The Secret Life of the Brain

THE SECRET LIFE OF THE BRAIN reveals the fascinating processes involved in brain development across a lifetime. The five-part series, which will premiere nationally on PBS in winter 2002, informs viewers of exciting new information in the brain sciences, introduces the foremost researchers in the field, and utilizes dynamic visual imagery and compelling human stories to help a general audience understand otherwise difficult scientific concepts (go).

Wednesday, 15 August 2007

Averroes' commentary on De Anima

On the Soul (Greek Περὶ Ψυχῆς (Perì Psūchês), Latin De Anima) is a major treatise by Aristotle, outlining his philosophical views on the nature of living things. His discussion centres on the kinds of souls possessed by different kinds of living things, distinguished by the different life-processes those organisms go through. Thus plants have the capacity for nourishment and reproduction, the minimum that must be possessed by any kind of living organism. Lower animals have, in addition, the powers of sense-perception and self-motion (action). Humans have all these as well as intellect.
The notion of soul used by Aristotle is only distantly related to the usual modern conception. He holds that the soul is the form, or essence of any living thing; that it is not a distinct substance from the body that it is in; that it is the possession of soul (of a specific kind) that makes an organism an organism at all, and thus that the notion of a body without a soul, or of a soul in the wrong kind of body, is simply unintelligible. (He speculates that some parts of the soul--the intellect--may be conceived to exist without the body, but most cannot.) It is difficult to reconcile these points with the popular picture of a soul as a sort of spiritual substance "inhabiting" a body. Some commentators have suggested that Aristotle's term soul is better translated as lifeforce.

Averroes (Ibn Rushd) (1126-1198) was an Andalusian-Arab philosopher and physician. He wrote commentaries on most of the surviving works of Aristotle. These were not based on primary sources (it is not known whether he knew Greek), but rather on Arabic translations. On each work, he wrote the Jami, the Talkhis and the Tafsir which are, respectively, a simplified overview, an intermediate commentary with more critical material, and an advanced study of Aristotelian thought in a Muslim context. The terms are taken from the names of different types of commentary on the Qur'an.

Wednesday, 11 July 2007

Saturday, 7 July 2007

Super-Kamiokande

It is believed soon after the big bang, when the universe was at a very high temperature, many neutrinos were produced. In addition, when a star explodes as a supernova, many neutrinos are emitted. Neutrinos are also copiously produced in nuclear reactions in the core of the sun. Also cosmic rays which come into the earth's atmosphere and interact with oxygen or nitrogen nuclei produce neutrinos. Purposes of the research are to elucidate the source of energy of the sun and detect the properties of the enigmatic neutrinos by observing these neutrinos with considerable precision.The detector consists of an inner volume and an outer volume which contain 32,000 tons and 18,000 tons of pure water respectively. The outer detector is used to veto entering cosmic ray muons and is used as a buffer to keep radiation emitted by the surrounding rock and walls from entering the inner volume. The inner detector has 11,200 photomultiplier tubes (PMTs) attached to the bottom, top and sides facing inward. The PMTs collect the pale blue light called Cerenkov light which is emitted by particles travelling fast as light in the water. By measuring the direction and intensity of this light,information about particle interactions such as neutrino interactions or proton decay can be determined (Official Website).

Monday, 2 July 2007

Simple Creatures, Intriguing Finds

Researchers look to fruit flies and tiny worms for greater understanding of neurodegenrative diseases such as Alzheimer's and Parkinson's. Fruit flies have many genes in common with higher animals, including humans. Researchers can easily transplant genes from humans into fruit flies. Finding mutations and observing the characteristics they produce are easier in fruit flies than in other types of animals.
Feany’s laboratory has bred a strain of the fruit fly Drosophila melanogaster that models Parkinson’s disease. Her team implanted mutant genes in the flies for a protein called alpha-synuclein.
Flies carrying the mutant genes lose dopamine-producing neurons in the brain’s substantia nigra, just as humans with Parkinson’s do. Also, fibrous bundles of alpha-synuclein form in the insects’ neurons. Bundles of the same structure and composition (called Lewy bodies) develop in the brain cells of people with Parkinson’s.
Cellular changes in the flies correlate with behavioral changes. Normal fruit flies climb up the sides of plastic vials. Middle-aged flies carrying the transplanted, mutant gene lose that ability.