Knowledge Update

​London, April 26 (IANS) Atmospheric carbon dioxide (CO2) concentration was the major driver behind the global climatic shifts that occurred in the "Eocene epoch" between 53 and 34 million years ago, says a new study.

The results support the view that elevated CO2 was responsible for the extreme warmth of the early Eocene and that CO2 decline was responsible for the subsequent cooling that ultimately led to the establishment of today’s polar ice sheets.

The researchers believe that the findings, published in the journal Nature, could help scientists better predict future climate change.

For the study, the research team developed new records of past CO2 levels by analysing ancient ocean sediments. 

"We cannot directly measure CO2 concentrations from that long ago,” said study lead author Eleni Anagnostou, postdoctoral researcher at University of Southampton in Britain.

"Instead we must rely on indirect ‘proxies’ present in the geological record. In this study, we used the chemical composition of marine fossils preserved in sediments to reconstruct ancient CO2 levels,” Anagnostou noted.

Applying pioneering geochemical techniques - developed at the University of Southampton over the past five years - the team used isotopes of the element boron in the shells as a proxy for pH (a measure of acidity), and used that to determine the atmospheric CO2 levels.

They found that between the early Eocene and the late Eocene, CO2 levels approximately halved. 

Using our current understanding of the relationship between sea surface temperature and CO2 at different latitudes, they also demonstrated that the changes in CO2 concentration can explain the majority of the cooling that occurred.

This research can also be used to gain a better understanding of how the Earth will respond to increasing levels of CO2 in the future, the scientists said.​

New York, April 23 (IANS) Contrary to popular perception, smoking cessation drugs do not increase the risk of serious neuropsychiatric adverse effects such as depression, hostility or suicidal behaviour, says a large study.

Researchers have found that compared to the nicotine patch and a placebo the smoking cessation drugs varenicline and bupropion do not show a significant increase in neuropsychiatric adverse events. 

"There are one billion smokers in the world and nearly six million smoking-related deaths each year, but there are only three approved medication treatments for quitting: nicotine replacement therapies like the patch and the two non-nicotine medications, bupropion and varenicline," said first author of the study Robert Anthenelli, professor at the University of California San Diego School of Medicine.

The study, published online in the journal The Lancet, is important because it prospectively examined the neuropsychiatric safety risks and quit-enhancing potential of the three medication classes versus placebo in a rigorous, adequately-sized, randomised controlled trial, Anthenelli said.

The researchers sought to directly assess the safety and efficacy of varenicline and bupropion compared to the nicotine patch and to a placebo in smokers with and without psychiatric disorders. 

The study involved examination of more than 8,000 smokers seeking to quit in 16 countries over a period from November 2011 to January 2015. 

Trial participants, investigators and research personnel were blinded to who received which treatment.

In terms of safety, approximately two percent of non-psychiatric participants reported moderate or severe adverse neuropsychiatric events for any of the treatments.

In the cohort of participants with psychiatric disorders, moderate and severe adverse neuropsychiatric events were slightly higher across the board: 6.5 percent for varenicline, 6.7 percent for bupropion, 5.3 percent for the nicotine patch and 4.9 percent for placebo.

Anthenelli said the risk difference in the incidence of serious neuropsychiatric adverse events for varenicline and bupropion was not significantly higher than placebo - but that psychiatric patients trying to stop smoking are likely to have more confounding factors in treatment and appear to have a harder time quitting.

​New York, April 24 (IANS) Researchers have found that adding salt to metal oxides increases their energy storage capacity by increasing their surface area.

The team, including researchers from Drexel University in the US, Huazhong University of Science and Technology (HUST) and Tsinghua University in China, published the results in the journal Nature Communications.

The results show that using salt crystals as a template to grow thin sheets of conductive metal oxides make the materials turn out larger and more chemically pure -- which makes them better suited for gathering ions and storing energy.

"The challenge of producing a metal oxide that reaches theoretical performance values is that the methods for making it inherently limit its size and often foul its chemical purity, which makes it fall short of predicted energy storage performance," said Jun Zhou, an author of the research, said.

"Our research reveals a way to grow stable oxide sheets with less fouling that are on the order of several hundreds of times larger than the ones that are currently being fabricated," Zhou, who is also a professor at HUST's Wuhan National Laboratory for Optoelectronics, added.

In theory, the best materials for the job should be thin sheets of metal oxides, because their chemical structure and high surface area makes it easy for ions to attach -- which is how energy storage occurs.

But the metal oxide sheets that have been fabricated in labs thus far have fallen well short of their theoretical capabilities, the paper said.

"This method of synthesis, called 'templating' -- where we use a sacrificial material as a substrate for growing a crystal -- is used to create a certain shape or structure," said Yury Gogotsi, another author of the paper.

"The trick in this work is that the crystal structure of salt must match the crystal structure of the oxide, otherwise it will form an amorphous film of oxide rather than a thing, strong and stable nanocrystal. This is the key finding of our research -- it means that different salts must be used to produce different oxides," Gogotsi added.​

New York, April 24 (IANS) Despite having extremely underdeveloped muscles and wings, young birds may acquire a mature flight stroke early in life by initially relying more on their legs and wings for power, finds a new study.

Adult birds have large wings and robust interlocking forelimb skeletons that may help meet the demands of flight.

But, the juvenile birds have small "protowings" or "mini wings" and flexible joints that lack many of the hallmarks of advanced flight.

Despite these limitations, young birds can flap their wings as they run up slopes and even briefly fly, challenging longstanding ideas about the origin of flight and flight development, the researchers said.

The team used X-ray analysis to visualise skeletal movement as birds like Chukar partridges, Alectoris flapped their wings while trying to climb steep slopes.

The findings showed that when flap-running at similar levels of effort, juvenile and adult birds showed similar patterns of joint movement.

Despite their undeveloped anatomy, young birds appeared to produce all of the elements of the avian flight stroke and modify their wing stroke for different behaviours, much like adults.

The force generated by flapping may push the birds forward as well as upward, improving traction as they climb.

Understanding flapping behaviour in young birds may provide insight into the possible use of mini-wings by extinct theropod dinosaurs, before flight evolved, the researchers suggested in the study published in the journal PLOS ONE.

"Baby birds anatomically look a lot like some of the dinosaur fossils that we see," said Ashley Heers from American Museum of Natural History in US.

"And so, by studying baby birds and looking at how they actually use these dinosaur-like anatomies, we can get a better sense of how these long-extinct animals might have been using their wings," Heers concluded.​

New York, April 24 (IANS) Fructose, a sugar common in the western diet, can damage hundreds of brain genes in a way that could lead to a range of diseases -- from diabetes to cardiovascular disease, and from Alzheimer's to attention deficit hyperactivity disorder -- warns a new study.

However, the researchers discovered good news as well: An omega-3 fatty acid known as docosahexaenoic acid (DHA) seems to reverse the harmful changes produced by fructose.

"DHA changes not just one or two genes; it seems to push the entire gene pattern back to normal, which is remarkable," said Xia Yang, assistant professor at the University of California - Los Angeles (UCLA).

DHA enhances learning and memory. It is abundant in wild salmon (but not in farmed salmon) and, to a lesser extent, in other fish and fish oil, as well as walnuts, flaxseed, and fruits and vegetables, co-senior author Fernando Gomez-Pinilla, an UCLA professor, pointed out.

The research was published online in the journal EBioMedicine.

To test the effects of fructose and DHA, the researchers trained rats to escape from a maze, and then randomly divided the animals into three groups.

For the next six weeks, one group of rats drank water with an amount of fructose that would be roughly equivalent to a person drinking a liter of soda per day.

The second group was given fructose water and a diet rich in DHA. The third received water without fructose and no DHA.

After the six weeks, the rats were put through the maze again. The animals that had been given only the fructose navigated the maze about half as fast than the rats that drank only water -- indicating that the fructose diet had impaired their memory.

The rats that had been given fructose and DHA, however, showed very similar results to those that only drank water -- which strongly suggests that the DHA eliminated fructose's harmful effects.

Other tests on the rats revealed more major differences: The rats receiving a high-fructose diet had much higher blood glucose, triglycerides and insulin levels than the other two groups.

Those results are significant because in humans, elevated glucose, triglycerides and insulin are linked to obesity, diabetes and many other diseases.

The research team sequenced more than 20,000 genes in the rats' brains, and identified more than 900 genes that were altered by the fructose.

The altered genes they identified, the vast majority of which are comparable to genes in humans, are among those that interact to regulate metabolism, cell communication and inflammation.

Among the conditions that can be caused by alterations to those genes are Parkinson's disease, depression, bipolar disorder, and other brain diseases, Yang said.​

​London, April 24 (IANS) Far from making you smarter, electrical stimulation of the brain's cells while solving challenging tasks can lead to mental overload, warn researchers.

The researchers wanted to test whether a treatment that sends a very weak electrical current through the skull to the outer layers of the brain, so-called transcranial direct current stimulation (tDCS), can actually make us smarter.

The tasks for the participants were divided into three levels -- simple, medium and difficult.

The researchers found no effect of stimulation when participants performed the simple and medium tasks, yet they found a large negative effect on the most difficult tasks.

"tDCS had a disruptive effect only on the most difficult tasks that demanded a lot of concentration," said one of the lead researchers, James Roe from the University of Oslo in Norway.

"We saw that participants experienced severe problems concentrating when the task was most difficult and the brain was being stimulated," Roe noted.

"It was as though tDCS had completely overloaded a brain region crucial to performing the task, as though it crashed it," Roe explained in a paper published in the journal Neuropsychologia.

In recent times neuroscientists have been showing increased interest for tDCS. Many claim that the device can, among other things, help improve memory, increase self-control and make us more creative.

tDCS is already implemented in the rehabilitation of a range of psychiatric and neurological conditions, such as depression, stroke, Alzheimer's disease, fibromyalgia and tinnitus.

While the researchers acknowledged that tDCS can indeed have a positive impact, they said the study shed light on the effects of tDCS when we solve tasks of varying difficulty.​

​London, April 25 (IANS) Researchers have for the first time visually depicted the movement of dinosaurs around the world during the Mesozoic Era -- from about 252 to 66 million years ago -- including a curious exodus from Europe.

The analysis -- based on "network theory" used to gather internet data -- also reaffirms previous studies that have found that dinosaurs continued to migrate to all parts of the world after Pangaea -- a supercontinent that existed during the late Paleozoic and early Mesozoic eras -- split into landmasses that are separated by oceans.

The findings revealed that although continental splitting undoubtedly reduced intercontinental migration of dinosaurs, it did not completely inhibit it.

While "network theory" is commonly used in computer science for quantifying internet data, such as friend connections on Facebook, it has only recently been applied to biology research and this is the first study to use it to on dinosaur research

The analysis also showed that all connections between Europe and other continents during the Early Cretaceous period -- 125-100 million years ago -- were out-going.

While dinosaur families were leaving Europe, no new families were migrating into Europe.

"This is a curious result that has no concrete explanation. It might be a real migratory pattern or it may be an artefact of the incomplete and sporadic nature of the dinosaur fossil record," said lead researcher Alex Dunhill at University of Leeds in Britain.

For the study, published in the Journal of Biogeography, the team used the Paleobiology database that contains every documented and accessible dinosaur fossil from around the world.

Fossil records for the same dinosaur families from different continents were then cross-mapped for different periods of time, revealing connections that show how they have migrated.​

Washington, April 25 (IANS) In one of its most ambitious projects in deep space, a team of NASA researchers are proposing to send robots at the centre of icy moons to explore the subsurface ocean for presence of life.

The two possible candidates are: the icy moons of gas giants Jupiter and Saturn which harbour sub-surface oceans perfect for hosting life.

According to a recent study, Jupiter’s moon Europa is creating a strong gravitational pull which is creating more heat on the moon's ice-sheet that is enough to support a sub-surface ocean.

But it is Saturn's icy moon Enceladus -- 500 km in diameter and 1.272 billion km away from the Earth - that serves as a leading candidate for extra-terrestrial life.

This year, one of most promising proposals that NASA Innovative Advanced Concepts Programme (NIAC) has received is from the researchers at the Jet Propulsion Laboratory (JPL) at Pasadena, California - proposing robots to explore the icy moons.

The Icy-Moon Cryovolcano Explorer (ICE) project aims to land on these moons and send a robotic explorer down the ice volcano to deploy a submersible to explore the ocean.

With a thick icy crust, Europa may be tough for a drilling robot to reach the subsurface ocean so the researchers have now turned their eyes on Enceladus.

The data from NASA's Cassini probe has strongly indicated that the cryovolcanic plumes of Enceladus probably originate in a biomolecule-friendly oceanic environment.

Enceladus, which probably has an ocean underlying its icy surface, has somehow managed to sprout multiple fissures along its south pole.

A surface-to-subsurface robotic system, the ICE will land on the surface of an icy moon, traverse to a cryovolcano, descend into its opening, perform in-situ science in the vent or crevasse and ultimately deploy underwater vehicles to explore a subsurface ocean.

ICE involves three modules: Descent Module (DM), Surface Module (SM) and autonomous underwater vehicles (AUVs_.

DM will carry AUVs and descend into a vent by using a combination of roving, climbing and hopping, like an experienced human alpinist.
SM will stay on the surface, generating power and communicating with the Earth.

DM will rely on the power and communication link provided by SM through a cable to minimise the size and weight.

Once DM reach the subsurface ocean, it will launch the AUVs to explore the exotic environment that potentially harbours life.

ICE brings three unique benefits. First, it enables in-situ science in a cryovolcano vent.

Although orbiters can perform in-situ science of plumes, relatively large dust grains are hard to reach orbital altitude. Yet it is those mineral grains that carry rich information about the habitability of the subsurface ocean.

Second, ICE enables the exploration of subsurface oceans by providing an access to it.

Third, it enables the operation of AUVs in subsurface ocean by providing three essential services: communication, localisation and power.

"A successful completion of the project will mature this exciting concept into a credible element of the growing outer planets and icy moons exploration portfolio,” the US space agency said in a statement.​

New York, April 23 (IANS) Researchers have developed a new method to map and track the function of brain circuits affected by autism spectrum disorder (ASD), especially in boys and identify the most effective treatment for an individual.

The functional biomarker physically measures the progress of patients with behavioural problems -- a tool that has been elusive in autism treatment.

"This is significant because biomarkers give us a 'why' for understanding autism in boys that we haven't had before," said one of the researchers Kevin Pelphrey, professor and director of the Autism and Neurodevelopmental Disorders Institute at the George Washington University in the US. 

The team found that the brain scan data could be an effective indicator of the function of the circuit in younger children and older patients alike.

It is particularly relevant for ASD patients who are difficult to diagnose and treat by providing a more definitive diagnosis and in developing a treatment programme when it is not clear if behavioural, drug or a combination of the treatments will be most effective.

"The behavioural symptoms of ASD are so complex and varied it is difficult to determine whether a new treatment is effective, especially within a realistic time frame," said led author Malin Bjornsdotter, assistant professor at the University of Gothenburg in Sweden.

"Brain function markers may provide the specific and objective measures required to bridge this gap," she added in the paper published in the journal JAMA Psychiatry.

In addition, the study also provides evidence that brain imaging is an important intervention tool for autism than the currently used functional MRI. 

The team analysed a series of 164 images from each of 114 individuals and discovered the brain scans of the social perception circuits only indicated ASD in boys. 

As the method only works for boys with autism, the researchers are leading a large-scale, nationwide study of girls with autism to identify equivalent techniques that will work for them.​

​New York, April 21 (IANS) Although men and women are equally influenced by tobacco, males tend to smoke more than females, finds new research that investigated gender differences in tobacco use among hunter-gathering egalitarian tribes.

“Surprisingly, even there, smoking is definitely a male thing,” said lead researcher Casey Roulette, anthropologist at Washington State University.

The study which focused on West Africa's Aka pygmy tribe found one of the largest recorded male-biased gender difference in smoking prevalence. 

The findings showed that a mere five percent of women smoked when compared to 94 percent men.

The high use by Aka men is surprising given that they generally need to work a few days on a neighbouring farm to afford one pack of cigarettes, the researchers said. 

While men spend a greater portion of their income on tobacco than women do, female tribe members tend to give away a greater portion of the tobacco they purchase.

"This suggests that men value tobacco more than women do," Roulette added in the paper published in the journal Human Nature. 

While women are not prohibited from tobacco use, the team found that the Aka females shy away from smoking because it can harm their unborn babies and children.

Many simply dislike the taste, while others abstain because it makes them unattractive to suitors. 

On the other hand, women in this hunter-gatherer society prefer men who smoke because they link tobacco use to greater risk taking and a man's subsequent ability to fend for his family. Those women who do smoke tend to be beyond their childbearing years.

"The Aka say that a woman becomes more like a man after menopause, which might also influence smoking among older women," Roulette noted.​