Knowledge Update

​New York, March 14 (IANS) US researchers have developed a new hormone-based test that can better distinguish between the symptoms of depression and schizophrenia.

Depression is thought to affect over 300 million people worldwide and schizophrenia affects as many as 51 million people. 

Clinically, it is difficult to distinguish between these two diseases in their early phases, because symptoms are non-specific and relatively mild. 

In the study, led by researchers from Yale University in Connecticut, US, the researchers infused patients with a high concentration salt solution to induce the release of the hormone arginine-vasopressin (AVP), and then measured the level of the hormone in their blood. 

The results, reported in Experimental Physiology, revealed that AVP release can distinguish schizophrenia from depression.

Depressed patients showed an increased release of the hormone, while patients with schizophrenia showed a decreased response. 

Further, the novel method will help identify people whose depression or schizophrenia involves signalling via a receptor called NMDAR, and differentiate between the two diseases. 

In patients with schizophrenia the NMDA receptor signalling may be decreased, while it might be high in those with depression. 

This hormone test may be a simple way to distinguish and identify patients with NMDA receptor malfunction in each disorder, the researchers said. 

"This is the first objective, physiological marker for two major psychiatric disorders that, once fully developed into a clinical test, can allow for earlier and more accurate diagnosis, and selection of more appropriate medications for patients," said Handan Gunduz-Bruce from Yale University.

Distinguishing this specific form of these diseases could allow for earlier and more accurate diagnoses as well as more targeted treatment, Gunduz-Bruce added.

New York, March 14 (IANS) Researchers have found evidence of a white dwarf star orbiting a likely black hole at a distance of only 961,000 km -- just about 2.5 times the distance between the Earth and the Moon.

In a tightest orbital dance ever witnessed for a black hole and a companion star, the star whips around the black hole at an astonishing speed -- about two orbits an hour, said the study published in the journal Monthly Notices of the Royal Astronomical Society.

"This white dwarf is so close to the black hole that material is being pulled away from the star and dumped onto a disk of matter around the black hole before falling in," said study lead author Arash Bahramian, affiliated with the University of Alberta in Canada and Michigan State University in the US. 

"Luckily for this star, we don't think it will follow this path into oblivion, but instead will stay in orbit," Bahramian said.

Although the white dwarf does not appear to be in danger of falling in or being torn apart by the black hole, its fate is uncertain.

The stellar system, known as X9, is located in the globular cluster 47 Tucanae, a dense cluster of stars in our galaxy about 14,800 light years away from the Earth. 

"For a long time astronomers thought that black holes were rare or totally absent in globular star clusters," study co-author Jay Strader from Michigan State University said. 

"This discovery is additional evidence that, rather than being one of the worst places to look for black holes, globular clusters might be one of the best," Strader added.

For the study, the researchers used data from the Australia Telescope Compact Array as well as NASA's Chandra X-ray Observatory and NuSTAR telescope.

Washington, March 14 (IANS) Rapid loss of Arctic sea ice in recent decades is partly driven by natural swings, not just global warming triggered by human activities, says a study.

A shift in wind patterns is responsible for about 60 per cent of sea ice loss in the Arctic Ocean since 1979, the researchers found. 

Some of this shift is related to climate change, but the study showed that 30-50 per cent of the observed sea ice loss since 1979 is due to natural variations in this large-scale atmospheric pattern.

"Anthropogenic forcing is still dominant -- it's still the key player," said the study's lead author Qinghua Ding, climate scientist at the University of California at Santa Barbara in the US.

"But we found that natural variability has helped to accelerate this melting, especially over the past 20 years," Ding said.

The paper builds on previous work that found changes in the tropical Pacific Ocean have in recent decades created a "hot spot" over Greenland and the Canadian Arctic that has boosted warming in that region.

The hot spot is a large region of higher pressure where air is squeezed together so it becomes warmer and can hold more moisture, both of which bring more heat to the sea ice below. 

The new paper, published in the journal Nature Climate Change, focuses specifically on what this atmospheric circulation means for Arctic sea ice in September, when the ocean reaches its maximum area of open water.

"This study provides the mechanism and uses a new approach to illuminate the processes that are responsible for these changes," the study's second author Axel Schweiger, a University of Washington polar scientist who tracks Arctic sea ice, said. 

"The method is really innovative, and it nails down how much of the observed sea ice trend we've seen in recent decades in the Arctic is due to natural variability and how much is due to greenhouse gases," co-author David Battisti, Professor at University of Washington, noted.

The researchers believe that teasing apart the natural and human-caused parts of sea ice decline would help to predict future sea ice conditions in Arctic summer.

New York, March 12 (IANS) Children between age 3 and 7 who do not get enough sleep are more likely to have problems with attention, emotional control and peer relationships, says a study.

"We found that children who get an insufficient amount of sleep in their pre-school and early school-age years have a higher risk of poor neuro-behavioral function at around age 7," said lead researcher Elsie Taveras from the MassGeneral Hospital for Children in the US.

"The associations between insufficient sleep and poorer functioning persisted even after adjusting for several factors that could influence the relationship," Taveras said.

As in previous studies from this group examining the role of sleep in several areas of child health, the current study analysed data from Project Viva, a long-term investigation of the health impacts of several factors during pregnancy and after birth.

Information used in this study was gathered from mothers at in-person interviews when their children were around 6 months, 3 years and 7 years old, and from questionnaires completed when the children were aged 1, 2, 4, 5 and 6 years.

In addition, mothers and teachers were sent survey instruments evaluating each child's executive function - which includes attention, working memory, reasoning and problem solving -- and behavioural issues -- including emotional symptoms and problems with conduct or peer relationships, when children were around 7.

Among 1,046 children enrolled in Project Viva, the study team determined which children were not receiving the recommended amount of sleep at specific age categories -- 12 hours or longer at ages 6 months to 2 years, 11 hours or longer at ages 3 to 4 years, and 10 hours or longer at 5 to 7 years.

The study, published online in the journal Academic Pediatrics, found significant differences in the responses of parents and teachers to surveys regarding executive function and behavioural problems in 7-year-old children depending on how much sleep they regularly got at younger ages.

New York, March 11 (IANS) Even while you are taking rest, your brain networks may be waiting in a state of potentiation to execute even the simplest of behaviours, a finding that may help in improving treatments for neuropsychiatric syndromes, an Indian-origin researcher has showed.

In the study, the researchers studied brain network interactions between two important brain regions: the dorsal anterior cingulate cortex (dACC) -- used for control -- and the supplementary motor area (SMA) -- used for motor movements -- during a simple motor control behaviour, for example tapping forefinger to a visual cue.

The results, published in the journal PLoS One, showed that the network interactions from the SMA to the dACC increased, during the rest periods that alternated between the motor behaviour task.

"These results suggest that directional interactions from the SMA to the dACC during the rest period may in fact potentiate task-related interactions in the opposite direction," said Vaibhav Diwadkar, Professor at Wayne State University in Michigan, US.

For the study, the team used a simple experimental task, having each participant perform a simple motor control behaviour -- tapping their forefinger to a visual cue -- that alternated between behaviour and rest. Brain activity was acquired using functional MRI (fMRI). 

The results reveal aspects not only of normative brain function but may also provide new directions for characterising disordered network interactions in neuropsychiatric syndromes, Diwadkar added.

​Washington, March 10 (IANS) NASA has announced that its upcoming mission to explore the habitability of Jupiter's icy moon Europa will be officially called Europa Clipper.

The mission is being planned for launch in the 2020s, arriving in the Jupiter system after a journey of several years, NASA said in a statement on Friday.

Europa has long been a high priority for exploration because it holds a salty liquid water ocean beneath its icy crust. 

The ultimate aim of Europa Clipper is to determine if Europa is habitable, possessing all three of the ingredients necessary for life -- liquid water, chemical ingredients, and energy sources sufficient to enable biology, the US space agency said. 

Previously, when the mission was still in the conceptual phase, it was sometimes informally called Europa Clipper, but NASA has now adopted that name as the formal title for the mission.

The moniker harkens back to the clipper ships that sailed across the oceans of Earth in the 19th century. 

Clipper ships were streamlined, three-masted sailing vessels renowned for their grace and swiftness. 

These ships rapidly shuttled tea and other goods back and forth across the Atlantic Ocean and around globe.

In the grand tradition of these classic ships, the Europa Clipper spacecraft would sail past Europa at a rapid cadence, as frequently as every two weeks, providing many opportunities to investigate the moon up close. 

The prime mission plan includes 40 to 45 flybys, during which the spacecraft would image the moon's icy surface at high resolution and investigate its composition and the structure of its interior and icy shell.

"During each orbit, the spacecraft spends only a short time within the challenging radiation environment near Europa. It speeds past, gathers a huge amount of science data, then sails on out of there," said Robert Pappalardo, Europa Clipper project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.

New York, March 10 (IANS) Higher exposure to some chemicals added to furniture, electronics and numerous other goods to prevent fires may put kids at increased risk of developing aggression and hyperactivity, says a study.

The researchers studied the behavioural effects of organophosphate-based flame retardants (OPFRs) on young children.

"When we analysed behaviour assessments and exposure levels, we observed that the children who had more exposure to certain types of the flame retardant were more likely to exhibit externalising behaviours such as aggression, defiance, hyperactivity, inattention and bullying," said corresponding author of the study Molly Kile, Associate Professor at Oregon State University in the US. 

Flame retardants are found throughout the built environment in furniture, mattresses, carpeting, electronics, vehicles and more. 

The chemicals are added to the products and are not bound in the material, which causes them to be released into indoor environments.

For this study, published in the journal Environmental Health, the research team recruited 92 children between ages three to five to wear a silicone wristband for seven days to measure exposure to flame retardants.

The researchers had parents or primary caregivers complete questionnaires about socio-demographics and the home environment, and preschool teachers completed behaviour assessments for each participating child. 

In all, researchers had complete data and wristband results for 69 children.

Their analysis showed that all of the children were exposed to some level of flame retardant. 

Children who had higher exposure rates of OFPRs showed less responsible behaviour and more aggression, defiance, hyperactivity, inattention and bullying behaviours.

​London, March 10 (IANS) Researchers have found the world's oldest crocodilian eggs that were laid 152 million years ago.

The eggs, discovered in cliffs in Portugal, were laid by close relatives of "true" crocodiles, a group called crocodylomorphs, which according to palaeontologists, had been two metres long.

"The fact that they are from the Late Jurassic period makes these eggs the oldest crocodilian eggs known so far," Joao Russo from the Nova University of Lisbon in Portugal was quoted as saying to the BBC.

"The fossil record tells us that crocodiles and their relatives (forming the larger group of crocodylomorphs) were much more diverse in the past, with different feeding habits, ecological niche distribution or morphology," he added.

The eggs were found in several clutches and appear to be of two different types, the researchers said in the paper published in the journal, Plos One.

"This new discovery from Portugal extends the knowledge of this type of egg by approximately 40 million years," Russo added.

Moscow, March 10 (IANS) Early life changes in brain activity and blood flow may be the reason why people tend to develop abnormally high blood pressure, or hypertension, researchers said.

High blood pressure is a condition in which the force of the blood against the artery walls is too high.

It is also often called the silent killer because it typically has no symptoms until after it has done significant damage to the heart and the arteries.

In 90-95 per cent of people, high blood pressure has no identifiable cause, yet it is a risk factor for diseases of the brain, kidneys, heart, eyes, and other parts of the body, said a group of researchers at the Institute of Cytology and Genetics in Russia. 

For the study, published in Experimental Physiology, the team investigated physiological changes in a rat model called ISIAH, short for inherited stress-induced arterial hypertension.

These rats develop high blood pressure at four to six weeks of age, and this is sustained throughout their lifetime.

The researchers compared the high blood pressure rats to a control group with normal blood pressure. 

As the mice in high blood pressure group grew older, changes in rates of blood flow in certain arteries were observed.

In addition, changes were found in the brain activity, specifically a decrease in the prefrontal cortex -- the brain region associated with cognition, decision-making and working memory -- as well as an increase in the hypothalamus -- an area of the brain that controls mood and appetite.

"The study of early physiological changes may help clarify the cause of high blood pressure. Understanding this could help us prevent the disease early on," said led author Alisa Seryapina from the Institute of Cytology and Genetics.