Oscar never let that slow him down. By the age of 11 he had been fitted with prosthesis and participated in rugby, water polo, and tennis. At 17 he suffered a serious knee injury while playing rugby and began physical therapy, where he discovered running. In the following years he set multiple world records in parathlete sprinting events and competed against able-bodied athletes in international events.
In 2007 the International Association of Athletics Federations (IAAF) banned "any technical device that incorporates springs, wheels or any other element that provides a user with an advantage over another athlete not using such a device" in running events, a move that it said was unrelated to Oscar's recent successes. Oscar successfully appealed the decision and won the right to compete in world sprinting and Olympic events, despite claims that his lightweight prosthesis gave him an unfair advantage.
In 2008 he competed for the South African track team for the Beijing Olympics but missed qualifying by .70 seconds. Still determined to achieve his dream of competing in the Olympics, he continued to train and on Sunday, August 28 he qualified for the 400m semi-finals at the IAAF World Athletics Championship in Daegu, South Korea. If he is able to run another 'A' qualification time he will have won the right to run with the best in London in 2012, and to be the first amputee in history to compete in the Olympic games.
Experiments at the LHC continue to find no evidence of supersymmetry.
Modern physics is an uneasy blend of two revolutionary ideas from the twentieth century: general relativity and quantum mechanics. Like two competing nations, their laws work well within their own specific realms (relativity at large scales, quantum mechanics at very small ones) but those laws break down and become meaningless or even incomprehensible in the opposite domain. Between the two is a nebulous border region where strange, inexplicable things seem to occur.
Supersymmetry is a theory that attempts to bridge that gap. Experimental physics has confirmed the existence of a great many particles which make up the matter and energy we interact with every day. Many, such as photons and electrons, you may have heard of. Several, like muons and top quarks, are more obscure. By positing the existence of a set of massive, hard to observe partner for each of these particles, theoretical physicists had hoped that they untangled the thorny mess of conflict between relativity and quantum mechanics. As an added plus, it was hoped that experimental data would reveal these massive partner particles to be the source of the mysterious dark matter which pervades our universe.
Enter the Large Hadron Collider (LHC), the most powerful and expensive science experiment ever conceived. At 27 km in circumference, it is more of a man-made geographic feature than an edifice, and it contains detectors sensitive enough to detect the flickering of a candle from the moon. One of its main missions has been to evaluate the different models of supersymmetry. The data so far is not encouraging.
At the Lepton Photon Symposium in Mumbai, India, physicists from CERN, which operates the LHC, presented data which fails to find any evidence of supersymmetry. Although the findings do not rule out every version of the theory, there is a sense among physicists that a new theory may be needed to explain this data.
"It could be that this whole framework has some fundamental flaws and we have to start over again and figure out a new direction," said Dr Joseph Lykken of Fermilab, a competing detector in the United States with much less sensitivity and power. Dr. Lykken is a leading proponent of supersymmtry and organizer of a yearly conference for its advocates. "It's a beautiful idea. It explains dark matter, it explains the Higgs boson, it explains some aspects of cosmology; but that doesn't mean it's right.
Interbreeding with Neanderthals was important for Human Immune System Evolution
While popular depictions of human evolution show a straight progression from ape to hominid to modern Homo sapiens, it has long been known that human evolution was actually a branching tree. Rival species of hominids coexisted and competed until modern humans outlived or exterminated their rivals by about 30,000 years ago. New data suggests that some of those branches of the human family tree live on in our DNA, specifically in certain genes in the immune system which may have been key to our success as a species.
The study was published in this week's Science magazine by a group of researchers from Stanford and other universities. In it they report that an important set of genes in the human immune system preserves evidence of ancient interbreeding between humans and two other species of hominids, Neanderthals and Denisovans.
Using gene sequencing, the researchers were able to identify an allele known as HLA-B*73 which is far more distantly removed from other typed of HLA genes than those genes are from each other. In essence, using a form of statistical analysis paired with comparisons to living human relatives (chimpanzees and gorillas), they could determine that the allele evolved in isolation from other human genes before being reintroduced by interbreeding sometime in our ancient past. Similar analyses of other alleles in the same region of the human genome reveals another likely cross-breeding event, with Neanderthals, at a different geographical location.
Previous work has suggested that Neanderthal genes make up between 1 and 6% of the human genome thanks to past interbreeding, but up to 50% of the genes examined by this study may have been inherited from those distant cousins. Such a high proportion suggests that these genes were important to the evolution of our immune systems and to our species' success in the face of constant threat from viral, bacterial, and parasitic infections.
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