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Science/Tech See other Science/Tech Articles Title: Physics duo wins the Nobel Prize for solving longstanding neutrino puzzle ScienceAlert... Canada’s Arthur B McDonald and Japan’s Takaaki Kajita have won this year’s Nobel Prize in Physics for their surprising discovery that tiny, subatomic particles called neutrinos have mass. Their experimental results forced scientists to rethink the Standard Model of particle physics that had successfully explained all observations of the subatomic world for decades. What are neutrinos? Neutrinos are produced when radioactive isotopes decay and have been shrouded in mystery ever since Wolfgang Pauli first proposed them in 1930. In the Standard Model, they were assumed to have no mass (like particles of light, photons) and be neutral (lacking electric charge). This would also explain why neutrinos usually pass straight through matter without interacting, making them extremely difficult to detect. Enormous instruments are required to observe them in sufficient numbers to study their properties. Neutrinos were first directly observed by the Cowan-Reines experiment in 1956, using neutrinos from a nuclear reactor and two large tanks of water. If a neutrino interacted with a nucleus in the detector, this would result in a flash of light that could be picked up by photomultiplier tubes that were sandwiched between the tanks. Frederick Reines was awarded the Nobel Prize in 1995 for this work. MissMJ - Own work by uploader, PBS NOVA, Fermilab, Office of Science, United States Department of Energy, Particle Data Group However, when detectors became sensitive enough to observe neutrinos created in nuclear reactions in the Sun, scientists faced a big problem. They had calculated the amount of neutrinos from the Sun that should be hitting Earth, but observed only a third of this number in their experiments. A further Nobel Prize was presented to Ray Davis in 2002 for this discovery. The mystery of these missing neutrinos was coined the "solar neutrino problem" and remained a puzzle for 40 years, until the collaborations led by Kajita and McDonald made their exciting discovery. Underground discovery There are three different types, or 'flavour', of neutrino - electron, muon and tau - which have slightly different mass and can interact with other particles in different ways. In 1998, Kajita, who now works at the University of Tokyo, announced that the Super-Kamiokande experiment in Japan had found that neutrinos 'oscillate' between these flavours, which is possible thanks to the strange rules of quantum mechanics. Super-Kamiokande detected muon-neutrinos coming straight from the atmosphere above, as well as those hitting the detector from below after having travelled through Earth. Since neutrinos barely interact, there should be equal numbers of neutrinos coming from the two directions. However, the muon-neutrinos that came straight down to Super-Kamiokande were more numerous than those that had passed through the planet. This indicated that muon-neutrinos that travelled longer had more time to oscillate into tau-neutrinos that could evade the detectors. Reuters These results were confirmed in 2001 by Arthur B McDonald, based at Queen’s University in Canada, and the Sudbury National Observatory collaboration, this time by detecting oscillations of neutrinos from the Sun. By carefully observing the interactions of neutrinos with 'heavy water', they were able to determine the total number of neutrinos, as well as the fraction of electron-neutrinos. They crucially showed that there were no missing neutrinos, once all the flavours had been taken into account. The discovery of Kajita and McDonald solved the solar neutrino problem as it could explain where the missing neutrinos had gone; they simply changed flavour on their way from the Sun to the detector, meaning that they couldn’t be recorded. It also showed that the Standard Model was incomplete, as such oscillations are impossible in the absence of neutrino masses. From their pioneering work, the neutrino field has boomed across the world, with experiments in every continent. Now that we know neutrinos have mass, we need new theories to explain how they acquire it. If new fundamental particles are responsible for neutrino masses, one of them could account for dark matter, a mysterious substance that makes up the vast majority of the matter in the Universe. Work is ongoing in this area and exciting discoveries may be just around the corner.The Conversation Ryan Wilkinson, PhD Candidate in the Institute for Particle Physics Phenomenology, Durham University and Celine Boehm, Senior Lecturer in the Department of Physics, Durham University This article was written by Ryan Wilkinson and Celine Boehm from Durham University in the UK, and was originally published by The Conversation. Read these next: This new metal box could help take physics beyond the Standard Model Watch: What are quarks? Nobel Prize awarded for pioneering discoveries in parasite-fighting drugs http://www.sciencealert.com/phys...gstanding-neutrino-puzzle Poster Comment: Here's a more comprehensive account of the medicine prize: The Nobel Prize in Physiology or Medicine was awarded on Monday to three scientists who discovered treatments for three of the most devastating parasite-borne diseases. Irish-born scientist William C. Campbell and Japanese scientist Satoshi Lmura were jointly awarded half the prize for their discovery of a therapy to treat infections caused by roundworm parasites. Chinese scientist Youyou Tu received the other half for her discovery of a new therapy for Malaria. Campbell and Lmura discovered the drug Avermectin, a modified form of which has dramatically reduced cases of river blindness and lymphatic filariasis/elephantiasis. It has also been effective against a growing number of other parasitic diseases. Both are caused by parasitic worms, which afflict an estimated third of the world’s population and are most prevalent in sub-Saharan Africa, South Asia, and Central and South America. River blindness (onchocerciasis), which afflicts at least 25 million people worldwide, causes chronic inflammation in the cornea that ultimately causes blindness. Lymphatic filariasis, which affects more than 120 million people, causes chronic swelling. It results in life-long stigmatising and disabling symptoms such as elephantiasis (lymphedema), extreme enlargement of a part of the body caused by blockage of the lymphatic system, and scrotal hydrocele, or swelling of the scrotum caused by a fluid-filled sac around the testicle. Lmura, an expert in isolating natural products, isolated new strains of the soil bacteria Streptomyces, which are known to produce a wide array of antibacterial compounds (including Streptomycin, the first antibiotic treatment for tuberculosis). He grew thousands of these strains in the lab, and selected 50 of the most promising to test further. Campbell studied Lmura's strains and found that a component in one of them effectively killed parasites in household and farm animals. The compound, which was purified and named Avermectin, was later chemically modified to a more effective form called Ivermectin. Campbell and Omura's work led to a new class of drugs that are extremely effective against the parasitic diseases above and others. Today, Ivermectin is freely available and used in all places where parasitic diseases are found. It is so effective that these diseases are on the verge of being eradicated. Malaria - a disease that is caused by the Plasmodium parasite that infects red blood cells - causes fever, and in severe cases, brain damage and death. It kills more than 450,000 people every year, mostly children. Worldwide, more than 3.4 billion people are at risk of contracting the disease. Malaria was traditionally treated with the drug chloroquine, or quinine, but the parasite started becoming resistant to it and eradication efforts failed. To develop a new drug in the 1960s, Chinese medical scientist Youyou Tu turned to old knowledge: traditional Chinese medicine. She screened many herbal remedies for malaria in animals, and found one, a compound found in the sweet wormwood plant (Artemisia annua), that seemed promising. To help her find a way to extract the compound, she consulted the ancient Chinese medical literature. Now known as Artemisinin, this compound is highly effective at treating malaria (though some strains in Asia are resistant). A 2010 study found that Artemisinin is estimated to reduce childhood deaths from Malaria by 30 percent more than quinine. In a statement, the Nobel Assembly said, "Campbell, Lmura and Tu have transformed the treatment of parasitic diseases. The global impact of their discoveries and the resulting benefit to mankind are immeasurable." This article was originally published by Business Insider. More from Business Insider: These groundbreaking prosthetics are so lifelike, they will make you question what's real Here's one of the biggest misconceptions of people who hate childhood vaccines NASA is recycling Space Shuttle engines for a very important purpose This 13-year-old came up with a brilliant way to stop people from driving drunk or high The truth about growing potatoes on Mars Read these next: New drug eliminates the malaria parasite within 48 hours in mice Guys, we're really close to eradicating the second disease ever from the planet Wealthy business man buys anti-parasitic drug, raises price 5,000% overnight Post Comment Private Reply Ignore Thread
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