Antacids weaken bones
BE CAREFUL before you take your next antacid. According to a study, antacids make bones weaker. Stomach acid in the gastrointestinal tract helps the intestines absorb and transfer calcium to the skeletal system. But antacids interrupt and even stop the gut from absorbing calcium. This leads to weaker bones and increases the chances of fractures. Researches had indicated that antacids block the absorption of important nutrients, but it was not known how or why this was happening in the body. The new study could help find ways to treat common clinical conditions which are currently being treated with medications that make bones weak. PLOS Genetics, March 26
ECOLOGY
Decreased resilience
Ecosystems CAN be resistant to changing climatic conditions. But their resistance is lowered when they face natural or anthropogenic disturbances such as fires or insect outbreaks. A study on seven shrublands in Europe found them to be quite resistant to moderate experimental warming and drought. Plants are particularly sensitive to changes in the early stages of their life and even small climatic changes can result in vegetation shifts when ecosystems are disturbed. The understanding will help predict the response of ecosystems to climate change. Nature Communications, March 24
BIOLOGY
On way out
Photo: JJ Harrison
The TASMANIAN swift parrot is undergoing a population collapse and could be extinct in 16 years. The parrot is a major pollinator of blue and black gum trees which are crucial to the forestry industry. Ironically, its habitat is being destroyed by the industry. A five-year study which tracked movement and breeding habits of the parrot predicts that their numbers would halve every year and there is a 94.7 per cent chance of its extinction. Biological Conservation, March 25 (online)
CLIMATE
Antarctica on thin ice
The THICKNESS of Antarctica's floating ice shelves has decreased by as much as 18 per cent in certain areas in the past two decades. Data collected by satellite radar altimetry missions of the European Space Agency during 1994-2012 shows that the ice volume decline is accelerating. At the current rates, the ice shelves in western parts of Antarctica could lose half their volume in 200 years. Science, March 26
What plants don't need
Light pollution has damaging effect on natural environment, including food chain
Source: Jon Bennie / University Of ExeterARTIFICIAL LIGHT can affect the growth and flowering of plants and even the number of insects dependent on them for food. Researchers simulated street lighting on artificial grassland plots containing pea aphids, sap-sucking insects, at night. These were exposed to two different types of light—a white light similar to newer commercial LED lights and an amber light similar to sodium street lamps popular in the streets of the UK. The low-intensity amber light was shown to inhibit, rather than induce, flowering in greater bird's foot trefoil, a wild plant of the pea family and a source of food for the pea aphid in grasslands. The number of aphids was also significantly suppressed under the light treatment due to the limited amount of food available. This shows that light pollution can have a permanent adverse impact on wildlife and ecosystem. Philosophical Transactions of the Royal Society B, March 16
CLIMATE CHANGE
Vanishing ponds of the Arctic
Warming TEMPERATURES are shrinking ponds in the Arctic tundra. Rise in temperature thaws nutrient-rich permafrost, releasing nutrients into ponds and enhancing plant growth, which takes over shallow ponds. More than 2,800 ponds in the northern region of Alaska's Barrow Peninsula were analysedwith photos and satellite images between 1948 and 2010. The number of ponds had decreased by 17 per cent, while pond size had shrunk by an average of one-third. Journal of Geophysical Research: Biogeosciences, March 12
HEALTH
Folic acid reduces risk of stroke
Adults WITH hypertension can reduce the risk of heart attack by taking folic acid supplements along with the prescribed medication, enalapril. More than 20,000 adults with high blood pressure but without a history of stroke in China were given a daily treatment of a single-pill combination of enalapril and folic acid or a tablet containing enalapril alone. The first stroke occurred in 282 participants in the enalapril-folic acid group compared to 355 participants in the enalapril group. This represents a 21 per cent reduction in the risk of first stroke. JAMA, March 15
OCEANS
Low oxygen affects some fish
The LEVEL of oxygen in water affects certain species of fish. Deep waters of the West Coast, US, are low on oxygen. Fish species such as spotted ratfish and petrale sole are most sensitive and their presence has been found to decline sharply in the West Coast, while greenstriped rockfish and dover remain unaffected by dissolved oxygen levels. Such co-relation can affect the marine chain by driving fish into habitats that are less desirable for fishing. Fisheries Oceanography, March 11
There was no Big Bang
A study has challenged the most prevalent theory on the origin of universe, reigniting an old debate
Source: JINHO JUNG
THE UNIVERSE did not start with the Big Bang. It did not have a beginning, nor will it ever end. It has been present forever, says a study which has formulated an equation. The most prevalent theory of origin of universe says it all began 13.8 billion years ago when everything was condensed in an infinitesimally small point, or singularity, and exploded and expanded. Mathematical calculations and Einstein's Theory of General Relativity explain the Big Bang and what happened after it, but they do not explain singularity or what happened before it. The new study claims to have prepared a model which suggests that singularity did not exist and gives the universe an infinite age.Physics Letters B, February 4
HEALTH
Sleep loss means weight gain
Experts HAVE claimed for years that lack of sleep leads to weight gain. It has now been proved true. Not only does a sleep-deprived person eat more, he/she also tends to eat more fat and less carbohydrates. It was thought that hormonal disturbances were behind this, but a study says salience network, an area of the brain, is the key. The five-day-four-night study on 34 people, whose brains were monitored through MRI, found that sleep-deprived subjects had an increased connectivity in salience network. It has a key role in determining responses to hunger stimuli. Scientific Reports, February 3
ECOLOGY
Resilient to mass extinctions
.jpg "Source: JOSHUA MAYER")
Source: JOSHUA MAYER
Earth Has witnessed five mass extinctions which changed the face of life on the planet. But plants coped with these events better than animals. The difference was most visible during the Cretaceous-Paleogene mass extinction, caused by the impact of an asteroid off the Mexican coast 66 million years ago. The event killed almost all the dinosaurs, but had limited impact on plant diversity. Negative rates of diversification (a scenario where more species die than are formed) never continued for long periods for plants. Over 20,000 plant fossils were analysed during the study.
New Phytologist, January 26
BIOLOGY
Iron, key to strong beaver tooth
Beavers do not brush yet their front teeth are strong enough to cut trees. This is because their teeth contain small amounts of iron that protect the enamel from wear and tear and acidic substance. Iron is present in an unstructured phase around the well-ordered "nanowires" that form the enamel's core. The find can be used in studies on tooth decay in humans. Science, February 13
Climate key to stripes
Zebras in warmer regions have bold stripes which help them cool
(Source: WOODLOUSE)
THERE HAVE been various theories on how the zebra got its stripes, ranging from those which say that the stripes make it difficult for predators to spot it to those which say they help ward off biting flies. A study whichanalysed the impact of 29 environmental factors, such as heat, flies and predators, on zebras across 16 locations in Africa found that temperature was the only variable with which zebra stripes had a correlation. Stripes help the zebra regulate its body temperature as they heat up at different rates and create "eddies of air" that have a cooling effect. This mechanism works best when stripes are bold. As a result zebras in areas with lower temperature have fewer and fainter stripes. Royal Society Open Science , January 14
HEALTH
High-risk contraceptive shots
Analysis of 12 observational studies involving 39,560 women in Africa indicates that the use of Depo-Provera, a hormonal birth control contraceptive shot, increases a woman's chance of getting infected with HIV by 40 per cent compared with women who use other methods or no method. About 144 million women use hormonal contraceptives in the world, of which 41 million opt for injectable forms. The Lancet Infectious Diseases, January 8 (online)
ECOLOGY
Parasitic infection trigger
Source: John Warren HuntleyRise in sea-level and temperature during the Holocene period (which began 11,700 years ago) lead to an increase in parasitic infections in molluscs. This has emerged from a study of mollusc fossils of the period. Similar changes in sea level and temperature, which are likely in foreseeable future, can infect molluscs again. And this time, the infection can spread to humans who eat clams and snails. About 56 million people globally suffer from food-borne parasitic infections. PNAS, December 2014
BIOLOGY
Environment trumps heredity
Environmental factors have a greater impact on an individual's immune system than hereditary factors. This has emerged from a study on 78 pairs of identical twins (almost 100 per cent genetically identical) and 27 pairs of fraternal twins (50 per cent genetically identical). Analyses of blood samples of these twins for 200 immune-system components found that environmental factors, such as exposure to toxins and vaccination, had a greater impact than heredity on about two-thirds of the components. Cell, January 15
Greening can backfire
Source: Javiera Balos Aalvarez
AN INCREASE in human-made carbon dioxide in the atmosphere could initiate a chain reaction between plants and microorganisms that would unsettle one of the largest carbon reservoirs on the planet—soil.Princeton University researchers report in a study that soil—which contains twice the amount of carbon in all plants and Earth's atmosphere combined—could become increasingly volatile as people add more carbon dioxide to the atmosphere. This is largely because of increased plant growth. Although a greenhouse gas and pollutant, carbon dioxide also supports plant growth. As trees and other vegetation flourish in a carbon dioxide-rich future, their roots could stimulate microbial activity in soil that in turn accelerates the decomposition of soil carbon and its release into the atmosphere as carbon dioxide. This effect counters current key projections regarding Earth's future carbon cycle, particularly that greater plant growth could offset carbon dioxide emissions as flora take up more of the gas. Nature Climate Change, December 24
BIOLOGY
Human egg, sperm created in lab
Scientists have created primordial germ cells—that will go on to become egg and sperm —using human embryonic stem cells. Although it had already been done using rodent stem cells, this is the first time it has been achieved efficiently using human stem cells. Cell, December 24
WILDLIFE
They are all related
Researchers from Japan and the US have compared gene sequences from 300 species of ants and found that one-tenth of all ants belong to just one genus, Pheidole. The researchers used these sequences to construct a tree that shows when and where each species evolved into new species. At the same time, they scoured the academic literature, museums around the world, and large databases to aggregate data on where all 1,200 or so Pheidole species live on Earth, creating a range map for each species. Their results suggest that Pheidoles evolved the same way twice, once to take over the New World, and then again to take over the Old World. Proceedings of the Royal Society Series B, December 24
GENETICS
Most cancer due to bad luck
US SCIENTISTShave created a statistical model that measures the proportion of cancer incidence, across many tissue types, caused mainly by random mutations that occur when stem cells divide. By their measure, two-thirds of adult cancer incidence are primarily due to "bad luck," when these random mutations occur in genes that drive cancer growth, while the remaining third are due to environmental factors and inherited genes. Science, January 2
Slow and steady
Despite evolving at a very slow pace, crocodiles have maintained genetic diversity
Photo: Jean-Philippe Gille
CROCODILES HAVE evolvedat a relatively slow rate-about a quarter of the rate of evolution of birds. But despite this, they have been able to maintain genetic diversity and survive millions of years. This has emerged from a study which compared the genome sequences of crocodiles, birds and turtles. The finding could help us understand their disease resistance, susceptibilities, adaptation to changing environments, and the diversity of captive and wild saltwater crocodile populations. The findings also provide clues to the characteristics of the common ancestors of the species. All extant crocodilian species-the Australian saltwater crocodile, the American alligator and the Indian gharial-were studied in the research. Science, December 12
HEALTH
Blood vessel de-clogger
It IS known that nitrite-rich food, such as beetroot, improve blood flow and are good for the heart. But how this happens was not clear. A study shows that nitrite works as a signal to haemoglobin, found in red blood cells, to form nitric oxide. This reduces platelet activation which causes blood clots. Researchers now aim to enhance this ability of haemoglobin to treat conditions such as hypertension, sickle cell disease and stroke.Journal of Biological Chemistry, December 3
ECOLOGY
Cologne camouflage
Source: Tane Sinclair-Taylor
Camouflage NEED not always be visual. Filefish use a cologne they prepare from the corals they eat to hide from the nose of predators. A study in Australia found that crabs were unable to smell filefish because they smelled like the corals. Insects are known to use the technique but this is the first time that a vertebrate has been found to use chemical camouflage. The find indicates that there could be more species which use it. Proceedings of the Royal Society B, December 10
GEOLOGY
Most abundant mineral named
The MINERAL that makes 38 per cent of Earth has finally been named-bridgmanite. For around 50 years, the mineral, a form of magnesium iron silicate found 660 km inside Earth, could not be studied or named because it did not survive the trip to the surface and its properties remained unknown. However, meteorites that fall on Earth have the same element in "frozen" form. X-ray analysis of Tenham, a meteorite that crashed in Australia in 1879 and had bridgmanite grains, revealed that mineral contains high amounts of ferric iron and sodium.Science, November 28
