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The world’s oceans at risk from rising acidity How cancer immunotherapy works Clothes make the bird... Prof Yash
Pal
THIS UNIVERSE |
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The world’s oceans at risk from rising acidity Rising ocean acidity is one of the results of increasing levels of carbon dioxide in the atmosphere and scientists are concerned that the phenomenon could make it impossible for key species in the marine food chain to make their protective shells. The scientists, led by Richard Feely of the US National Oceanic and Atmospheric Administration (NOAA), surveyed 13 different locations off the west coast of North America, from Canada to Mexico, and found higher-than-expected levels of acidity in seawater samples taken near the surface. “Our results show for the first time that a large section of the North American continental shelf is impacted by ocean acidification,” the scientists said in their study, published online in the journal Science. The survey took place in May and June last year using a research ship that collected seawater samples as it sailed across the North American continental shelf from Queen Charlotte Sound in Canada to San Gregorio Baja California Sur in Mexico. The scientists said that other regions of the world may also be affected to a similar extent, because rising levels of man-made carbon dioxide in the air cause ocean acidity to increase wherever the gas dissolves in seawater to form carbonic acid. Over the past 250 years, since the start of the industrial revolution, the amount of CO2 in the atmosphere has increased by about 100 parts per million and about a third of this extra carbon dioxide in the air is estimated to have dissolved in the oceans, where it has helped to raise acidity levels. “The atmospheric concentration of CO2 is now higher than it has been for at least the past 650,000 years, and is expected to continue to rise at an increasing rate, leading to significant changes in our climate by the end of the century,” the scientists said. Each day the oceans absorb about 30 million tonnes of carbon dioxide from the atmosphere. This increasing concentration of carbonic acid has changed the chemistry and the biology of the oceans to an extent that can now be detected by scientists. “This phenomenon, which is commonly called ‘ocean acidification’, could affect some of the most fundamental biological and geochemical processes of the sea in the coming decades, and could seriously alter the fundamental structure of pelagic (free-swimming) and benthic (seafloor) ecosystems,” the scientists said. — The Independent |
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How cancer immunotherapy works A 52-year-old man with advanced melanoma, the lethal form of skin cancer, has been successfully treated using just his own blood. The development has been hailed by British experts as an “exciting advance” in the use of cancer immunotherapy, which harnesses the body’s immune system to fight the disease. Researchers in the US who were treating the patient extracted white blood cells, the key component of the immune system, and grew one type — the infection-fighting CD4+ T cells — in the laboratory. The cloned T cells, which had been vastly expanded, were then reinfused to the patient to fight the cancer. The man was diagnosed with stage four melanoma, when death normally occurs within months. The cancer, triggered by sunburn, started in a mole on the skin and had spread to a lymph node in his groin and to his lungs. But, two months after the T-cell treatment, scans revealed no tumour. Two years later, when he was last checked, the man remained free of the disease. He had previously had surgery and drug treatment without any response. Melanoma is the deadliest form of skin cancer, causing 1,800 deaths a year in the UK. It is the fastest rising cancer, with cases up 40 per cent in the past decade. The cancer is caused by intermittent, intense exposure to the sun. The typical victim is the office worker who spends two weeks broiling on a beach each summer. Adults with fair skin who suffered severe sunburn before the age of 15 are at highest risk. Cassian Yee, who carried out the experimental treatment with colleagues at the Fred Hutchinson Cancer Research Centre in Seattle, said that one in four late-stage melanoma patients had the same type of immune system and tumour antigen as the patient, for whom the therapy could be effective. But he warned that they had only proved its success in one patient. “We were surprised by the anti-tumour effect of these CD4+ T cells and its duration of response. For this patient we were successful, but we would need to confirm the effectiveness of the therapy in a larger study.” The findings are published in The New England Journal of Medicine, which describes them in a commentary as a “novel strategy” which points to a “feasible new direction” for treatment. Louis Weiner, the author of the commentary and director of the Lombardi Comprehensive Cancer Centre in Washington, said that although it was too early to be sure of the significance of this one case, the indications were that it will give a substantial boost to the technique of cancer immunotherapy. “I suspect that if the destination is not yet at hand, it is in sight. The endgame has begun,” he said. Cancer immunotherapy is a growing area of research which has proved successful in some other cancers, including kidney cancer. The aim is to develop less toxic treatments which are at least as effective as chemotherapy and radiation. Ed Yong, a health information manager at Cancer Research UK, said: “While it’s always good news when anyone with cancer gets the all-clear, this treatment will need to be tested in large clinical trials to work out how widely it could be used.” Professor Peter Johnson, Cancer Research UK’s chief clinician and a consultant in Southampton, said: “Although the technique is complex and difficult to use for all but a few patients, the principle that someone’s own immune cells can be made to work in this way is very encouraging.” How immunotherapy works
— The Independent |
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A little strategically placed makeup quickly turns the wimpiest of male barn swallows into chick magnets, amping up their testosterone and even trimming their weight, new research shows. It’s a “clothes make the man” lesson that — with some caveats — also applies to human males, researchers say. Using a $5.99 marker, scientists darkened the rust-colored breast feathers of male New Jersey barn swallows, turning lighter birds to the level of those naturally darkest. They had already found, in a test three years ago, that the marked-up males were more attractive to females and mated more often. This time they found out that the more attractive appearance, at least in the bird world, triggered changes to the animals’ body chemistry, increasing testosterone. “Other females might be looking at them as being a little more sexy, and the birds might be feeling better about themselves in response to that,” said study co-author Kevin McGraw, an evolutionary biology professor at Arizona State University. McGraw said the findings are surprising, in part because the hormonal changes occurred after only one week. The study was published in Tuesday’s edition of the journal Current Biology. In the 30 male barn swallows who were darkened, testosterone was up 36 percent after one week, during a time of year when levels of that hormone would At the same time, testosterone levels in the 33 birds that didn’t get the coloring treatment fell by half, said lead author Rebecca Safran, an evolutionary biology professor at the University of Colorado in Boulder. “It’s the `clothes make the man’ ” idea, Safran said. “And your physiology accommodates this.” Before you feel superior to these birds, Safran cautioned, people’s mating systems are more similar to birds’ than we might like to admit. Barn swallows are “socially monogamous and genetically promiscuous, same as humans,” she said. “There are some interesting parallels, but we do need to be careful about making them.” In people, hormonal changes have been observed after changes in behaviour. A 1998 study found that loyal male fans of sports teams experienced a 20 percent rise in testosterone when their teams won. The researchers aren’t certain how the testosterone boost happens. It could be that because of the darkened color, the birds mate more often and that changes their testosterone levels. It could also be that because of the darkened colour, other males think the pecking order has changed and that boosts the darker swallows’ hormone levels. Or it could be both.
— AP
Monkeys who
know fishing Long-tailed macaque monkeys have a reputation for knowing how to find food — whether it be grabbing fruit from jungle trees or snatching a banana from a startled tourist. Now, researchers say they have discovered groups of the silver-haired monkeys in Indonesia that fish. Groups of long-tailed macaques were observed four times over the past eight years scooping up small fish with their hands and eating them along rivers in East Kalimantan and North Sumatra provinces, according to researchers from The Nature Conservancy and the Great Ape Trust. The species had been known to eat fruit and forage for crabs and insects, but never before fish
from rivers. “It’s exciting that after such a long time you see new behavior,” said Erik Meijaard, one of the authors of a study on fishing macaques that appeared in last month’s International Journal of Primatology. “It’s an indication of how little we know about the species.”
— AP |
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THIS UNIVERSE
Why is the shape of the rainbow that of a semi-circle, and not a full circle of seven colours? Also, why is a straight line rainbow not formed? Is it due to the shape of the earth? A rainbow is seen after it has rained, when tiny droplets of rain are still hanging in the atmosphere. We also need the Sun to illuminate these droplets. Also, the rainbow is seen in a direction opposite to that of the Sun. This last fact should make it clear that the rainbow does not result from a direct passage of light once through droplets. The process involves dispersion of light on entering a droplet, total internal reflection of this light at the back surface of the droplet and emergence in the direction of a person standing with the back of his head towards the Sun. As in passing through a prism in a lab most of the light is concentrated at the angle of minimum deviation with respect to the incident direction. Demonstrate it to your students using a prism sitting on a spectrometer table. When we are talking about an angle of minimum deviation we are talking of an ANGLE with respect to the incident direction. For the case of the rainbow in which two dispersions and a total internal reflection is involved the angle can be calculated and turns out to be about 42 degrees. (This depends on the refractive index of water). It is clear that concentration of light, being at an angle with respect to the direction of the Sun (usually behind us), has to be on a curve making and angle of 42 degrees. This has to be a circular curve. But it cannot be a full circle because the lower part goes behind the earth. On the other hand if you are flying in an airplane and sun is high in the sky, then looking down through a transparent window at the bottom of the plane you would be able to see a fully circular rainbow. I read somewhere that the whole of this universe is made up of strings. What are these strings themselves made up of? Is it possible to reach the ultimate particle
(or truth) by this reductionist technique, or do we need something holistic? I am not an expert in string theory. However, it would be wrong to call this as a reductionist approach. This is a bold attempt to look into the mind of nature in a way that all the forces that make up our universe should fall out in a
consistent way. No arbitrary assignment of properties and strengths of different forces might be needed. It is claimed if there is a God that thought of this creation he had to be some kind of string theorist! In this theory physical things emerge out of mathematical thought. I think there is also a belief that this was the only way a universe could have been designed. I personally feel these guys are too ambitious but they are certainly not reductionists. |
A significant increase in the acidity of the Pacific Ocean has been detected by scientists, who believe it could upset the delicate balance of marine ecosystems and lead to their collapse.