Knowledge Update

​London, Sep 21 (IANS) The upper depths of the world's oceans have warmed significantly since 1995, resulting in severe hurricanes, storm surges and an increase in the number of icebergs, according to a new report.

"Many people may associate warmer seas with the pleasant weather conditions they're used to experiencing while on holiday, but the fact of the matter is that an increase in sea temperatures is having a huge impact on the world's weather," said one of the study authors Grant Bigg from University of Sheffield in Britain. 

"Our study has shown that severe hurricanes, storm surges, melting ice in the Arctic region and changes to El Nino are all being caused by sea temperatures rising across the planet. These are all things that can have a devastating impact on the way we live our lives," Bigg noted.

The rise in ocean temperatures has caused an increase in the number of severe hurricanes and typhoons, such as Hurricane Katrina, which devastated New Orleans in 2005, and Typhoon Haiyan, which caused massive destruction in the Philippines in 2013, the study said.

Hurricanes have even been observed in the South Atlantic for the first time since satellite records began in the 1970s. 

The area was traditionally viewed as an unlikely region for hurricane formation because of its cooler sea surface temperatures, however in 2004 conditions were more favourable than normal due to warmer ocean temperatures, spawning Hurricane Catarina off the coast of Brazil.

The report, presented at the IUCN World Conservation Congress in Hawaii, also showed that warmer seas have resulted in a significant loss of ice in the Arctic region. 

The atmosphere in the polar regions has warmed at about twice the average rate of global warming with Arctic coasts experiencing a rise in the occurrence of storm surges.

This increase in storm surges can have a detrimental effect on fragile ecosystems in the area, such as low relief tundra, underlain by permafrost, according to the report.

Warmer oceans have also caused a distinct change in El Nino events -- the warmer currents associated with the cycle have now been observed towards the central Pacific rather than the west, according to the Sheffield scientists.

"We hope that this research, together with studies presented by our colleagues in Hawaii this week, will help to shape the response of conservation and sustainable development to ocean warming," Bigg said.

​New York, Sep 21 (IANS) Have you ever wondered how our brain enables us to read a book even in a noisy cafe by filtering out the irrelevant stimuli coming through ears and "gating" in the relevant ones in our vision -- words on a page? It is possible due to the inhibitory neurons that the brain employs in such situations, new research suggests.

The inhibitory neurons are brain's traffic cops that help ensure proper neurological responses to incoming stimuli by suppressing other neurons and working to balance excitatory neurons, which aim to stimulate neuronal activity, said the study.

"Our computational model shows that inhibitory neurons can enable a neural circuit to gate in specific pathways of information while filtering out the rest," said senior author Xiao-Jing Wang, Professor at New York University.

Of particular interest to the team was a specific subtype of inhibitory neurons that targets the excitatory neurons' dendrites -- components of a neuron where inputs from other neurons are located. 

These dendrite-targeting inhibitory neurons are labeled by a biological marker called somatostatin and can be studied selectively by experimentalists. 

The researchers proposed that they not only control the overall inputs to a neuron, but also the inputs from individual pathways -- for example, the visual or auditory pathways converging onto a neuron.

"This was thought to be difficult because the connections from inhibitory neurons to excitatory neurons appeared dense and unstructured," Guangyu Robert Yang, a doctoral candidate in Wang's lab, observed. 

"Thus a surprising finding from our study is that the precision required for pathway-specific gating can be realised by inhibitory neurons," Yang noted.

The study's authors used computational models to show that even with the seemingly random connections, these dendrite-targeting neurons can gate individual pathways by aligning with excitatory inputs. 

In the study published in the journal Nature Communications, they showed that this alignment can be realised through synaptic plasticity -- a brain mechanism for learning through experience.

​New York, Sep 21 (IANS) Rocks formed by the grinding together of other rocks during earthquakes are rich in trapped hydrogen and similar seismic activity on Mars may produce enough hydrogen to support life, a study says.

"Mars is not very seismically active, but our work shows that 'Marsquakes' could produce enough hydrogen to support small populations of microorganisms, at least for short periods of time," said first author of the study Sean McMahon from Yale University, New Haven, Connecticut, US.

"NASA has plans to measure seismic activity on Mars during its 2018 InSight mission, and our data will make those measurements all the more interesting," study co-author John Parnell from University of Aberdeen in Scotland said.

The researchers studied rock formations around active fault lines in the Outer Hebrides, off the coast of Scotland. 

"Previous work has suggested that hydrogen is produced during earthquakes when rocks fracture and grind together. Our measurements suggest that enough hydrogen is produced to support the growth of microorganisms around active faults," McMahon said.

While humans and other animals get their energy mainly from the reaction between oxygen and sugar, bacteria use a wide array of alternative reactions to obtain energy. 

The oxidation of hydrogen gas, for example, generates enough energy for bacteria deep in the Earth's subsurface.

"This is just one part of the emerging picture of the habitability of the Martian subsurface, where other sources of energy for life may also be available. The best way to find evidence of life on Mars may be to examine rocks and minerals that formed deep underground around faults and fractures, which were later brought to the surface by erosion," McMahon pointed out.

The study was published in the journal Astrobiology.

​New York, Sep 21 (IANS) A computer-based brain training programme developed at Yale University helps improve student performance in reading and math -- in some cases even more than individualised tutoring, according to a new study.

In a study of more than 500 second graders, math and reading scores on school- administered tests increased significantly more in children who used the brain training programme Activate during the school year than in control classes.

The effect on math achievement scores was greater than what has been reported for one-on-one tutoring, said the study published in the journal Scientific Reports.

"The programme increases focus, self-control, and memory -- cognitive skills essential for learning," said lead author of the study Bruce Wexler, Professor Emeritus of Psychiatry at Yale University in New Haven, Connecticut, US . 

"And these are the exactly the cognitive skills affected by poverty, so we believe brain training programmes like Activate can help reduce the achievement gaps related to poverty that are seen in schools across the country," Wexler noted.

The findings illustrate that the benefits of the training, conducted three times a week for a four-month period, extend beyond getting better on the training games themselves and lead to improved learning of material that is very different from that in the games.

In a second finding from the same study, researchers discovered that doing a five-minute brain warm-up game just before beginning an Activate math or reading curricular content game can increase math and reading performance. 

New York, Sep 21 (IANS) Exposure to certain common chemicals called endocrine-disrupting chemicals found in several consumer products, including plastic bottles, may reduce levels of vitamin D in the bloodstream, says a study.

Endocrine-disrupting chemicals (EDC) are found in everyday products and throughout the environment. Bisphenol A (BPA), a known EDC, is often found in plastics and other consumer products. 

"Nearly every person on the planet is exposed to BPA and another class of endocrine-disrupting chemicals called phthalates, so the possibility that these chemicals may even slightly reduce vitamin D levels has widespread implications for public health," said the study's first author Lauren Johns from the University of Michigan School of Public Health in Ann Arbor.

EDCs are chemicals or mixtures of chemicals that can cause adverse health effects by interfering with hormones in the body. 

"Vitamin D plays a broad role in maintaining bone and muscle health. In addition, low vitamin D levels have been implicated in outcomes of numerous conditions such as cardiovascular disease, diabetes and cancer," Johns said.

The study examined data from 4,667 US adults who participated in the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2010. 

The participants provided blood samples so their vitamin D levels could be measured. To measure EDC exposure, the participants had their urine analysed for substances left behind after the body metabolised phthalates and BPA.

The study, published in the Journal of Clinical Endocrinology & Metabolism, found people who were exposed to larger amounts of phthalates were more likely to have low levels of vitamin D in the bloodstream than the participants who were exposed to smaller amounts of the EDCs. 

The link was strongest in women. There also was an association between exposure to higher levels of BPA and reduced vitamin D levels in women, although the relationship was not statistically significant in men.

"More research is needed into why an association exists, but it is possible that EDCs alter the active form of vitamin D in the body through some of the same mechanisms that they use to impact similar reproductive and thyroid hormones," senior author of the study John Meeker, Professor at the University of Michigan, explained.

​New York, Sep 19 (IANS) Refuting claims that it is updating the astrological signs, NASA has said that it did not do it as the space agency studies astronomy not astrology.

"We did not change any Zodiac signs, we just did the math. The Space Place (an educational page for kids run by NASA) article was about how astrology is not astronomy, how it was a relic of ancient history and pointed out the science and math that did come from observations of the night sky," NASA spokesperson Dwayne Brown told Gizmodo.

Last week a news spread that 86 per cent of the people now have a different star sign as NASA had decided to update the astrological signs for the first time in 2,000 years. 

In NASA's educational page for children called Space Place, the agency discussed how, some 3,000 years ago, the ancient Babylonians were keen sky-watchers and thought that the changing positions of constellations throughout the year could be linked to certain behaviours or events on Earth.

As a result of this, those sky-watchers invented the zodiac.

"So, as Earth orbits the Sun, the Sun would appear to pass through each of the 12 parts of the zodiac. Since the Babylonians already had a 12-month calendar (based on the phases of the Moon), each month got a slice of the zodiac all to itself," Science Alert reported on Monday citing the article in Space Place. 

But seeing as this happened 3,000 years ago, things were a bit arbitrary, and for whatever reason, the Babylonians left a constellation out of their zodiac -- Ophiuchus, the report said. 

"Even then, some of the chosen 12 did not fit neatly into their assigned slice of the pie and slopped over into the next one," Space Place noted, adding, "To make a tidy match with their 12-month calendar, the Babylonians ignored the fact that the Sun actually moves through 13 constellations, not 12."

NASA said that due to a tiny wobble in the Earth's axis, the position of those constellations has shifted. This means that those constellations are no longer in the same spots today as they were when the ancient Babylonians were looking up.

But that has nothing to do with change of zodiac signs.

​London, Sep 19 (IANS) Individuals with autism spectrum disorder (ASD) are either over- or under-sensitive to sensory information.

The severity of social difficulties experienced by them daily may increase according to their senstitiveness to touch, which may be more than their visual or auditory sensitivities, a study has found.

The study showed that the sense of touch may play a more crucial role in individuals with ASD than previously assumed. 

For some with ASD, busy and crowded environments such as supermarkets are overwhelming, while others may be less sensitive to pain, or dislike being touched.

They may have difficulties in determining which tactile sensations belong to the action of someone else, the study said.

"The results can yield a novel and crucial link between sensory and social difficulties within the autism spectrum," said Eliane Deschrijver from Ghent University in Belgium.

A normal human brain can detect very quickly when a touch is not their own. However, this process is different in the brain of adults with ASD. 

Their brain may signal to a much lesser extent, when an external touch sensation does not correspond to their own touch.

Individuals who experienced stronger sensory difficulties showed a stronger disturbance in their brain. They were also the ones that experienced more severe social difficulties, the researchers said.

"It is the first time that a relationship could be identified between the way individuals with ASD process tactile information in their brain, and their daily social difficulties," Deschrijver noted.

"These findings can primarily lead to a better understanding of the complex disorder, and of associated difficulties," added Roeljan Wiersema, Professor at Ghent University in Belgium.

In the study, the researchers investigated how the brain of individuals with and without ASD uses own touch to understand touch sensations in the actions of others.

In a series of experiments with electro-encephalography (EEG), the scientists showed that the brain activity of adults with ASD differs from that of adults without ASD while processing touch.

The findings were published online in the journal Social, Cognitive and Affective Neuroscience.

New York, Sep 19 (IANS) Larger-bodied marine animals are more likely to become extinct than smaller creatures, and humans are to be largely blamed for this, say researchers.

It is a pattern that is unprecedented in the history of life on Earth, and one that is likely driven by human fishing, said the study published in the journal Science.

"We've found that extinction threat in the modern oceans is very strongly associated with larger body size," said Jonathan Payne, a paleobiologist at Stanford University's School of Earth, Energy & Environmental Sciences.

"This is most likely due to people targeting larger species for consumption first," Payne noted.

For the study, the researchers put modern extinction in context by comparing them with Earth's five previous mass extinctions.

"We used the fossil record to show, in a concrete, convincing way, that what is happening in the modern oceans is really different from what has happened in the past," study co-author Noel Heim, a postdoctoral researcher in Payne's lab, said. 

Specifically, the authors found that the modern era is unique in the extent to which creatures with larger body sizes are being preferentially targeted for extinction. 

"What our analysis shows is that for every factor of 10 increase in body mass, the odds of being threatened by extinction go up by a factor of 13 or so," Payne said. 

"The bigger you are, the more likely you are to be facing extinction," Payne noted.

The selective extinction of large-bodied animals could have serious consequences for the health of marine ecosystems, the scientists say, because they tend to be at the tops of food webs and their movements through the water column and the seafloor help cycle nutrients through the oceans, the scientists said.

​New York, Sep 20 (IANS) Some mosquitoes are more likely to feed on cattle than on humans if they carry a specific chromosomal rearrangement in their genes, thus reducing their odds of transmitting the malaria parasite, a new study has found.

The parasite causing the disease is carried by Anopheles mosquitoes species that transmit it to humans by biting them. One of these species is Anopheles arabiensis, which is the primary vector of malaria in East African countries.

Rates of malaria transmission depends on whether mosquitoes bite humans. When mosquitoes bite cattle, malaria does not spread because these animals are dead-end hosts.

The transmission also depends whether mosquitoes rest after their meals in areas where they are likely to encounter pesticides, the study said.

Using a population genomics approach, the study established an association between human feeding and a specific chromosomal rearrangement in the major east African malaria vector.

"Whether there is a genetic basis to feeding preferences in mosquitoes has long been debated. This work paves the way for identifying specific genes that affect this critically important trait," said Bradley Main, researcher at the University of California - Davis, in the US.

In the study, the team sequenced the genomes of 23 human-fed and 25 cattle-fed mosquitoes collected indoors and outdoors from the Kilobero Valley in Tanzania.

An analysis of these genomes allowed them to identify a chromosomal rearrangement -- known as the 3Ra inversion -- associated with cattle feeding.

It however did not appear to have an impact on the mosquitoes' resting behaviours.

Using genetics to better understand and track mosquito behaviour can improve local control strategies.

This knowledge may also open novel avenues for stopping malaria's spread, such as genetically modifying mosquitoes to prefer cattle over people, the researchers noted, in the paper published in the journal PLOS Genetics.