Knowledge Update

​New York, July 16 (IANS) Turtles developed shells as a tool for burrowing underground to escape harsh climatic conditions, a study has found, contradicting the traditional belief that they used their shells for their protection.

The study was conducted on new fossil material, a 15 cm long specimen of the 260- million-year-old, partially shelled, proto turtle or stem turtle, Eunotosaurus Africanus from the Karoo Basin of South Africa, which indicated that the initiation of rib broadening was an adaptive response to fossoriality. 

Numerous fossorial animal -- one that is adapted to digging and life underground such as the badger -- correlates are expressed throughout Eunotosaurus' skeleton.

These stem turtles indicate that the shell did not evolve for protection, rather adaptation related to digging was the initial impetus in the origin of the shell.

"The earliest beginnings of the turtle shell was not for protection but rather for digging underground to escape the harsh South African environment where these early proto turtles lived," said lead author Tyler Lyson, Paleontologist Denver Museum of Nature & Science in Colorado, US.

The adaptations related to fossoriality likely facilitated movement of stem turtles into aquatic environments early in the groups' evolutionary history, and this ecology may have played an important role in stem turtles surviving the Permian/Triassic extinction event that occurred about 252-million-years ago, said the paper published in the journal Current Biology.

Further, the developmental and fossil data showed that one of the first steps toward the shelled body plan was broadening of the ribs.

The distinctly broadened ribs -- that play a crucial role in ventilating the lungs and are used to support the body during locomotion -- has a serious impact on both breathing and speed in these quadrupedal animals. 

These broadened ribs stiffen the torso, which shortens an animals stride length and slows it down, interfering with breathing.

"We knew from both the fossil record and observations how the turtle shell develops into modern turtles that one of the first major changes toward a shell was the broadening of the ribs," Lyson added.

The broad ribs of Eunotosaurus provide an intrinsically stable base on which to operate a powerful forelimb digging mechanism.

Most of these features are widely distributed along the turtle stem and into the crown clade, indicating the common ancestor of Eunotosaurus and modern turtles possessed a body plan significantly influenced by digging, the researchers concluded.​

​Toronto, July 15 (IANS) After analysing Kepler space telescope data, astronomers from the University of Toronto, Canada, have found a clear understanding yet of a class of exoplanets called 'Warm Jupiters', showing that many have unexpected planetary companions.

The analysis provides strong evidence of the existence of two distinct types of 'Warm Jupiters', each with their own formation and dynamical history.

The two types include those that have companions and thus, likely formed where we find them today and those with no companions that likely migrated to their current positions.

“Our findings suggest that a big fraction of 'Warm Jupiters' cannot have migrated to their current positions dynamically and that it would be a good idea to consider more seriously that they formed where we find them,” said Chelsea Huang, a Dunlap Fellow at the Dunlap Institute for Astronomy and Astrophysics, University of Toronto.

Warm Jupiters are large, gas-giant exoplanets -- planets found around stars other than the Sun.

They are comparable in size to the gas-giants in our solar system.

But unlike the Sun's family of giant planets, “Warm Jupiters” orbit their parent stars at roughly the same distance that Mercury, Venus and the Earth circle the Sun.

They take 10 to 200 days to complete a single orbit.

Because of their proximity to their parent stars, they are warmer than our system's cold gas giants -- though not as hot as “Hot Jupiters” which are typically closer to their parent stars than Mercury.

Instead of finding "lonely", companion-less “Warm Jupiters”, the team found that 11 of the 27 targets they studied have companions ranging in size from Earth-like to Neptune-like.

“The number of 'Warm Jupiters' with smaller neighbours may be even higher. We may find that more than half have companions,” Huang noted in a paper published in the Astrophysical Journal.​

London, July 15 (IANS) Levels of global biodiversity loss are no longer within the safe limit and this may negatively impact the ecosystem function and the sustainability of human societies, a new study has revealed.

According to the study, levels of biodiversity loss are so high that if left unchecked, they could undermine efforts towards long-term sustainable development.

"We know biodiversity loss affects ecosystem function but how it does this is not entirely clear. What we do know is that in many parts of the world, we are approaching a situation where human intervention might be needed to sustain ecosystem function," said Tim Newbold of the University College of London.

The researchers found that grasslands, savannas and shrublands were most affected by biodiversity loss, followed closely by many of the world's forests and woodlands. 

The ability of biodiversity in these areas to support key ecosystem functions such as growth of living organisms and nutrient cycling has become increasingly uncertain, suggested the study published in the journal Science.

For 58.1 per cent of the world's land surface which is home to 71.4 per cent of the global population, the level of biodiversity loss is substantial enough to question the ability of ecosystems to support human societies, revealed the study.

"It's worrying that land use has already pushed biodiversity below the level proposed as a safe limit," said Andy Purvis, Professor at the Imperial College, London.

The team used data from hundreds of scientists to analyse 2.38 million records for 39,123 species at 18,659 sites which were then applied to estimate how biodiversity in every square kilometre land has changed since before humans modified the habitat.

They found that biodiversity hotspots are facing threat, showing a decline. Other high biodiversity areas, such as Amazonia, which have seen no land use change have higher levels of biodiversity and more scope for proactive conservation.​

​New York, July 15 (IANS) By creating a virtual tissue model of diabetes in the eye, researchers have shown precisely how a small protein that can both damage or grow blood vessels in the eye causes vision loss and blindness in people with diabetes.

The study, reported in the journal PLOS Computational Biology, could also lead to better treatment for diabetic retinopathy, which currently requires multiple, invasive procedures that are not always effective in the long term.

A common cause of vision loss in people with diabetes, diabetic retinopathy is responsible for one percent of all blindness worldwide.

"With the current epidemic of diabetes in adults, the number of people with vision damage from diabetes will continue to rise," said lead author on the study Thomas Gast from Indiana University School of Optometry in the US.

"This paper establishes a step-by-step pathway from a diabetic's elevated blood sugars to the vascular complications in the eye. Therapeutically, understanding a disease can lead to improved treatments," Gast noted.

A major way diabetic retinopathy threatens vision is diabetic edema. In this condition, the smallest vessels supplying the retina with oxygen become leaky, causing fluid to swell the central retinal area and impairing the type of vision required for precise activities such as reading.

This happens because the loss of blood flow in a vessel causes the local oxygen level to drop, which stimulates local production of vascular endothelial growth factor, or VEGF, a protein which in most tissues causes the growth of new blood vessels to repair damage. 

However, in a retina with elevated sugar levels, instead of repairing the damage, physicians observe a cascade of damage that propagates from the initial blocked vessel. 

The rate and area of the damage's progression also vary greatly between patients in a seemingly unpredictable way.

The virtual retina model in the study provided strong evidence for why this pattern of disease progression was so variable, and predicted where damage would occur next. 

It showed that the blockage of one vessel causes a local loss of oxygen in the retina, which triggers release of VEGF that spreads over a larger region, which, in turn increases the probability of blockage in the surrounding vessels, creating a "domino effect".​

​New York, July 16 (IANS) A malfunctioning immune system may be responsible for social deficits in neurological diseases such as autism-spectrum disorders and schizophrenia, suggests new research.

"Our findings contribute to a deeper understanding of social dysfunction in neurological disorders, such as autism and schizophrenia, and may open new avenues for therapeutic approaches," said Vladimir Litvak, Assistant Professor at the University of Massachusetts Medical School in the US.

The study was published in the journal Nature.

The researchers developed and employed a novel systems-biology approach to investigate the complex dialogue between immune signalling and brain function in health and disease.

Using this approach, the scientists found that immune system signalling can directly affect, and even change, social behaviour in mice and other model animals.

The researchers predicated an unexpected role for interferon gamma (IFN-?), an important substance secreted by immune cells, in promoting social brain functions.

In the course of the research, they found that blocking IFN-? in mice made mouse brains become hyperactive and caused atypical social behaviour. 

Restoring of IFN-?-signalling in the brain normalised brain activity and social behaviour. 

"The brain and the adaptive immune system were thought to be isolated from each other, and any immune activity in the brain was perceived as a sign of pathology,” said Jonathan Kipnis from the University of Virginia.

"And now, not only are we showing that they are closely interacting, but some of our behaviour traits might have evolved because of our immune response to pathogens," Kipnis explained.​

​New York, July 17 (IANS) Researchers have created a comprehensive molecular atlas of brain development in non-human primate that could shed crucial light on what makes human brain development distinct.

This analysis uncovered features of the genetic code underlying brain development in our close evolutionary relative, while revealing distinct features of human brain development by comparison.

"This is the most complete spatiotemporal map we have for any mammal's development, and we have it in a model system that provides directly meaningful insight into human brain development, structure, and function," said Ed Lein, investigator at Allen Institute for Brain Science, a US-based non-profit medical research organisation.

"This exceptional dataset is useful for exploring precisely where and when genes are active in relation to the events of brain development and the onset of brain disorders," Lein noted in an analysis of the atlas published in the journal Nature.

The study is based on the US National Institutes of Health (NIH) Blueprint Non-Human Primate (NHP) Atlas, a publicly available resource created by the Allen Institute and colleagues at the University of California, Davis and the California National Primate Research Centre.

The goal of the NHP atlas was to marry the techniques of modern transcriptomics with the rich history of anatomical developmental studies by measuring gene activity at a series of ten important stages in prenatal and postnatal brain development.

At each stage, a technique called laser microdissection was used to precisely isolate fine layers and nuclei of cortical and subcortical brain regions associated with human psychiatric disease, thereby creating a high resolution time series of the generation and maturation of these brain regions and their underlying cell types.

The authors collaborated with colleagues at the Baylor College of Medicine to use this molecular map to pinpoint when and where candidate genes for diseases like autism and schizophrenia become active.

"This tremendous resource is freely available to the research community and will guide important research into the etiology of many developmental disorders for years to come," Michelle Freund, programme officer at National Institute of Mental Health, noted.​

​Tokyo, July 17 (IANS) While it is widely accepted that an asteroid impact caused the mass extinction of dinosaurs and other life forms, researchers have been stumped by the process of how. In other words, they had figured out the killer, but not the murder weapon.

A new study has now said that when the asteroid hit the oil-rich region of Yucatan Peninsula in Mexico, a massive amount of soot was ejected which then spread globally, causing global cooling, drought and limited cessation of photosynthesis in oceans.

This could have been the process that led to the mass extinction of dinosaurs, said the research team from Tohoku University and the Japan Meteorological Agency's Research Institute.

The asteroid, also known as the Chicxulub impactor, hit Earth some 66 million years ago, causing a crater more than 180 km wide.

Professor Kunio Kaiho from Tohoku University and his team analysed sedimentary organic molecules from two places -- Haiti, which is near the impact site, and Spain, which is far.

They found that the impact layer of both areas have the same composition of combusted organic molecules showing high energy.

This, they believe, is the soot -- a strong, light-absorbing aerosol -- from the asteroid crash.

The results were significant because they could explain the pattern of extinction and survival.

Earlier theories had suggested that dust from the impact may have blocked the sun, or that sulphates may have contaminated the atmosphere.

But it was unlikely that either phenomenon could have lasted long enough to have driven the extinction, the researchers noted.

According to their study, when the asteroid hit the region, the massive amount of soot had caused a prolonged period of darkness which led to a drop in atmospheric temperature.

The soot aerosols caused colder climates at mid-high latitudes, and drought with milder cooling at low latitudes on land.

This in turn led to the cessation of photosynthesis in oceans in the first two years, followed by surface-water cooling in oceans in subsequent years.

This rapid climate change is believed to be behind the loss of land and marine creatures over several years, suggesting that rapid global climate change can and did play a major role in driving extinction.

The study was published in the journal Scientific Reports.​

New York, July 16 (IANS) Turtles developed shells as a tool for burrowing underground to escape harsh climatic conditions, a study has found, contradicting the traditional belief that they used their shells for their protection.

The study was conducted on new fossil material, a 15 cm long specimen of the 260- million-year-old, partially shelled, proto turtle or stem turtle, Eunotosaurus Africanus from the Karoo Basin of South Africa, which indicated that the initiation of rib broadening was an adaptive response to fossoriality. 

Numerous fossorial animal -- one that is adapted to digging and life underground such as the badger -- correlates are expressed throughout Eunotosaurus' skeleton.

These stem turtles indicate that the shell did not evolve for protection, rather adaptation related to digging was the initial impetus in the origin of the shell.

"The earliest beginnings of the turtle shell was not for protection but rather for digging underground to escape the harsh South African environment where these early proto turtles lived," said lead author Tyler Lyson, Paleontologist Denver Museum of Nature & Science in Colorado, US.

The adaptations related to fossoriality likely facilitated movement of stem turtles into aquatic environments early in the groups' evolutionary history, and this ecology may have played an important role in stem turtles surviving the Permian/Triassic extinction event that occurred about 252-million-years ago, said the paper published in the journal Current Biology.

Further, the developmental and fossil data showed that one of the first steps toward the shelled body plan was broadening of the ribs.

The distinctly broadened ribs -- that play a crucial role in ventilating the lungs and are used to support the body during locomotion -- has a serious impact on both breathing and speed in these quadrupedal animals. 

These broadened ribs stiffen the torso, which shortens an animals stride length and slows it down, interfering with breathing.

"We knew from both the fossil record and observations how the turtle shell develops into modern turtles that one of the first major changes toward a shell was the broadening of the ribs," Lyson added.

The broad ribs of Eunotosaurus provide an intrinsically stable base on which to operate a powerful forelimb digging mechanism.

Most of these features are widely distributed along the turtle stem and into the crown clade, indicating the common ancestor of Eunotosaurus and modern turtles possessed a body plan significantly influenced by digging, the researchers concluded.​

​New York, July 16 (IANS) Soon after technology giant Apple reported its first-ever quarterly drop in iPhone sales in April, a new report has found that "the outlook for iPhone demand keeps getting murkier" as other leading smartphone brands like Samsung make inroads in the market.

The number of iPhone units sold would tumble 12 per cent from 2015 and the upcoming iPhone 7 would be "a marginal cycle at best", New York Post reported, quoting a Wall Street analyst on Friday.

Recently, retail data insights and consulting business Kantar Retail reported that Samsung’s Galaxy 7 line of smartphones grabbed 16 per cent of total sales in the US during the three months ended May 31, exceeding the 14.6 per cent of sales for the iPhone 6s.

As the momentum of the 6s has slowed down, investors are worried about iPhone 7 that the device might not be a significant upgrade.

Mark Moskowitz of Barclays forecast that this year’s iPhone unit sales would total 203.7 million down from 231.5 million last year. 

The report by Kantar not only mentioned the threat to Apple but to its biggest rival Samsung as well by the increasing competition from lower-priced rivals, most notably China-based Xiaomi and Huawei.

“Apple and Samsung should stop worrying so much about each other and take a look around them,” Kantar analyst Lauren Guenveur was quoted as saying, noting that Huawei aims to overtake Apple as the second-largest smartphone seller by 2020.

Guenveur also noted that “rumours are swirling” that Google will soon introduce a handset of its own.

Earlier this week, research firm IDC said Apple’s share of the worldwide PC market shrank to 7.1 per cent from 7.4 per cent as customers hold out for a long-awaited refresh to the MacBook Pro line.

Apple is slated to give an update on recent demand when it reports results on July 26.​

New York, July 14 (IANS) A gene associated with Alzheimer's disease may shrink brain structures and lower thinking skills as early as in childhood, decades before the illness actually appears, says a research.

The findings showed that children with epsilon(E)4 variant of the apolipoprotein-E gene showed differences in their brain development compared to children with E2 and E3 forms of the gene and were more likely to develop Alzheimer's disease.

In such children the size of the hippocampus -- a brain region that plays a role in memory -- was found to be approximately 5 per cent smaller.

Specifically, the children as small as of age three showed up to 50 per cent lower scores on tests of executive function, working memory and attention. 

Each person receives one copy of the gene (E2, E3 or E4) from each parent, so there are six possible gene variants: E2E2, E3E3, E4E4, E2E3, E2E4 and E3E4, the researchers explained.

Further, children younger than eight and with the E4E4 genotype typically had lower measures on a brain scan as well as had lower scores on a test on memory and thinking skills. 

"Studying these genes in young children may ultimately give us early indications of who may be at risk for dementia in the future and possibly even help us develop ways to prevent the disease from occurring or to delay the start of the disease," said study author Linda Chang from the University of Hawaii in Honolulu, US.

However, children older than 8 with these two genotypes had similar and normal test scores compared to the other children.

"These findings mirror the smaller volumes and steeper decline of the hippocampus volume in the elderly who have the E4 gene," Chang added in the work published online in the journal Neurology.

For the study, the team analysed 1,187 children from ages three to 20 years who had genetic tests and brain scans and as well as took tests of thinking and memory skills. 

The children had no brain disorders or other problems that would affect their brain development, such as prenatal drug exposure.​