Knowledge Update

​Moscow, June 16 (IANS) Russia's economic recession is expected to end this year, Economic Development Minister Alexei Ulyukayev said on Thursday.

"The low point of recession has passed, and there is a rapid economic recovery," Ulyukayev said at the St. Petersburg International Economic Forum that started earlier in the

​New York, June 16 (IANS) Scientists have discovered an ancient space rock in a Swedish quarry which is a type of meteorite never before found on the Earth and can shed more light on the evolution of life.

The new meteorite, called Ost 65, appears to be from the missing partner in a massive asteroid collision 470 million years ago. 

The collision sent debris falling to the Earth over about a million years and may have influenced a great diversification of life in the Ordovician Period which lasted almost 45 million years, beginning 488.3 million years ago and ending 443.7 million years ago. 

One of the objects involved in this collision is well-known. It was the source of L-chondrites, the most common type of meteorite. But the identity of the object that hit it has been a mystery.

"In our entire civilisation, we have collected over 50,000 meteorites and no one has seen anything like this one before," said study co-author Qing-zhu Yin, professor of geochemistry and planetary sciences at University of California-Davis. 

"Discovering a new type of meteorite is very, very exciting,” he added in a paper reported in the journal Nature Communications.

Ost 65 was discovered in Sweden's Thorsberg quarry, source of more than 100 fossil meteorites. 

Measuring just under four-inches wide, it looks like a gray cow patty plopped into a pristine layer of fossil-rich pink limestone. 

By measuring how long Ost 65 was exposed to cosmic rays, the team established that it travelled in space for about a million years before it fell to the Earth 470 million years ago. 

This timeline matches up with L-chondrite meteorites found in the quarry.

According to the researchers, about 100 times as many meteorites slammed into the Earth during the Ordovician Period compared with today owing to the massive collision in the asteroid belt. 

This rain of meteorites may have opened new environmental niches for organisms, thus boosting both the diversity and complexity of life on Earth.

"I think this shows the interconnectedness of the entire solar system in space and time, that a random collision 470 million years ago in the asteroid belt, could dictate the evolutionary path of species here on Earth," Yin explained.​

​New York, June 16 (IANS) Obese people may find it difficult to stay away from sweet foods than individuals who are lean, because of a dysfunction in their brains, finds a new study.

Extra body fat can exert effects on how our brains perceive rewards when we eat sweets, the study said.

The findings showed that the reward system in obese people brains' operates in a different manner than in those who are lean.

As people move from adolescence to adulthood, they tend to be less fond of sweets as a result of a decrease in dopamine levels -- the main chemical in the brain that makes us feel good. 

The fall in dopamine levels makes the older adults less attracted to sweets.

Both younger age and fewer dopamine receptors were found to be associated with a higher preference for sweets in those of normal weight. 

"We found disparities in preference for sweets between individuals and also found individual variations in dopamine receptors," said Tamara Hershey, Professor at Washington University.

"Some people have high levels and some low. In people with normal weight having fewer dopamine receptors was associated with a higher preference for sweets," Hershey noted.

However, in people with obesity, that is not the case, the researchers said.

Dysfunctioning in the brain's reward system of obese individuals makes them more vulnerable to sweet cravings.

The relationship between their age, sweetness preferences and dopamine receptors also did not follow the pattern seen in people who weighed less.

Insulin resistance or some other metabolic change linked to obesity could contribute to the absence of these associations in the obese group, the researchers explained.

"We believe we may have identified a new abnormality in the relationship between reward response to food and dopamine in the brains of individuals with obesity," lead author M Yanina Pepino, Assistant Professor at Washington University, added.

For the study, published online in the journal Diabetes, the team analysed 20 healthy volunteers who were aged between 20-40 years and compared them with 24 people considered obese, each of whom had a body mass index of 30 or higher. 

The participants received drinks containing varying levels of sugar to determine the degrees of sweetness each individual preferred. 

Positron emission tomography (PET) scans was conducted to identify dopamine receptors linked to rewards in each person's brain. ​

New York, June 17 (IANS) Exercise, even a small amount, can help alleviate symptoms of attention-deficit/hyperactivity disorder (ADHD) in adults, say researchers.

ADHD symptoms can lead to depression, low energy and motivation, poor performance at work or school and also increased traffic accidents.

A single bout of exercise has psychological benefits for adults with these elevated ADHD symptoms, which lead to anxiety, the findings showed.

"Exercise is already known as a stress reducer and mood booster, so it really has the potential to help those suffering with ADHD symptoms," said the study's senior author Patrick O'Connor, professor at University of Georgia in the US. 

"And while prescription drugs can be used to treat these symptoms, there's an increased risk of abuse or dependence and negative side effects. Those risks don't exist with exercise," O'Connor said.

The study tested 32 young men with elevated ADHD symptoms who cycled at a moderate intensity for 20 minutes on one day, and on another day sat and rested for 20 minutes as a control condition. 

The participants were asked to perform a task requiring focus both before and after the different conditions, and researchers noted leg movement, mood, attention and self-reported motivation to perform the task.

As a result, researchers found that it was only after the exercise when the participants felt motivated to do the task. They also felt less confused and fatigued and instead felt more energetic. 

The study was published in the journal Medicine and Science in Sports and Exercise.

Interestingly, leg movements and performance on the task did not change after the exercise - rather, the exercise helped the young men feel better about doing the task.​

​New York, June 17 (IANS) Women who go to college intending to become engineers stay in the profession less often than men, as a result of gender disparities faced by them during their assignments, finds a new study.

Overall, about 20 per cent of under-graduate engineering degrees are awarded to women, but only 13 per cent of the engineering workforce is female, the study said.

The findings showed that women often feel marginalised, especially during internships, other summer work opportunities, or team-based educational activities.

"Gender makes a big difference. Informal interactions with peers and everyday sexism in teams and internships are particularly salient building blocks of [gender] segregation," said Susan Silbey, Professor at Massachusetts Institute of Technology.

Women are more likely than men to enter the field of engineering with the explicit notion that it will be a "socially responsible" profession that will "make a difference in people's lives."

But, gender dynamics seem to generate more opportunities for men to work on the most challenging problems, while women tend to be assigned routine tasks or simple managerial duties.

"For many women, their first encounter with collaboration is to be treated in gender stereotypical ways," the researchers rued.

“As a result of their experiences at these moments, women who have developed high expectations for their profession -- expecting to make a positive social impact as engineers -- can become disillusioned with their career prospects," Silbey added.

For the study, the team asked more than 40 undergraduate engineering students to keep twice-monthly diaries that generated more than 3,000 individual diary entries that the scholars systematically examined.

The diary entries frequently mentioned the everyday gender disparities these women faced.

Thus, such gender disparities leads women to question whether other professions could be a better vehicle for affecting positive change in the society -- their key motivator -- and thus prompt them to leave engineering, said the paper published in the journal Work and Occupations.​

​London, June 17 (IANS) Unable to retain your memory? A new study suggests that physical exercise four hours after learning can significantly improve long-term memory and memory traces.

The findings showed that students who exercised four hours after learning retained the information for two days in comparison to those who exercised either immediately or not at all. 

Exercise after the stipulated time was associated with more precise representations in the hippocampus -- a brain region important for learning and memory.

"It shows that we can improve memory consolidation and long term memory by doing sports after learning," said Guillen Fernandez from Radboud University in the Netherlands.

"The study suggests that appropriately timed physical exercise can improve long-term memory and highlights the potential of exercise as an intervention in educational and clinical settings," Fernandez noted.

The study, published in the journal Current Biology, involved 72 students, who were made to learn 90 picture-location associations for 40 minutes. 

After that, they were randomly assigned to one of three groups: first group performed the exercise immediately after learning. The second group performed the exercise four hours later and the third did not perform any exercise.

The exercise consisted of 35 minutes of interval training on an exercise bike at an intensity of up to 80 per cent of participants' maximum heart rates.

​London, June 17 (IANS) Being overweight during adolescence can put men at significantly higher risk of developing severe liver disease later in life, says a study.

The findings are based on 40 years follow-up of study of nearly 45,000 Swedish men.

The study showed that adolescent males with a body mass index (BMI) above 25 are at a 64 per cent increased risk of developing severe liver diseases and liver cell cancer in their late lives. 

Even for one kg/m2 increase in BMI, obese males can face a five per cent increased risk, the study said.

"It is possible that this increased risk is caused by a longer exposure to being overweight, compared to becoming overweight or obese later in life and that individuals with a longer history of being overweight have an increased risk of severe liver disease," said lead investigator Hannes Hagstrom from Karolinska University in Sweden.

In addition, overweight and obesity are associated with a worse prognosis in several liver diseases, such as non-alcoholic fatty liver disease (NAFLD), hepatitis B and C as well as alcoholic liver disease.

The increased risk of a high BMI for the development of severe liver disease later in life is already present from an early age, commented the researchers.

"The increased prevalence of overweight and obesity has also contributed to the worldwide rise in liver diseases," Hagstrom added.

It has been estimated that if current trends continue, there will be more than two billion overweight and over one billion obese individuals worldwide by 2030, said the paper published in the Journal of Hepatology. 

The researchers examined approximately 45,000 Swedish men, over a period of 40 years, to investigate if the body mass index (BMI) in adolescence developed severe liver diseases in later life. 

The results of the follow-up revealed 393 men diagnosed with severe liver diseases and being overweight was a risk factor for developing severe liver disease after adjusting for a variety of confounding factors, including alcohol and tobacco. ​

​New York, June 16 (IANS) Shedding new light on why extra weight is so difficult to shed permanently, researchers have found that overeating reduces levels of a hormone that signals the feeling of fullness in the brain, potentially promoting more eating.

Through earlier studies on colon cancer, Thomas Jefferson University researchers led by Scott Waldman noticed that a hormone called uroguanylin also appeared to play a role in obesity. 

Their studies had shown that in non-obese mice, uroguanylin would travel to the brain, where it produced a feeling of fullness. But it was unclear what happened to this signaling in the obese state.

In the current study, the researchers looked at mice who were overfed, and saw that the small intestines of these mice had stopped producing uroguanylin. 

The receptors for uroguanylin that reside in the brain were intact, and had even increased in number, but hormone itself was no longer being made, suggesting that overeating had caused its production to shut down. 

However, when the animals were put on a diet, the guanylin production resumed.

"What's interesting is that it didn't matter whether the mice were lean and overfed, or obese and overfed - urogaunylin production stopped in both groups of animals when they got too many calories," Waldman said.

The research was published in the journal Nutrition & Diabetes.

"Taken together, these experiments show that excess calories - either from fat or carbohydrates - stress small intestinal cells so that they stop producing uroguanylin, which helps people feel full after eating," Waldman said. 

"What we don't know is how much is too much and what molecular sensor makes that decision," he pointed out.​

New York, June 15 (IANS) Both lack or excess of sleep can lead to health risks like hypertension, obesity, diabetes and depression among children and teenagers, warns a research team led by an Indian-origin scientist.

The findings showed that insufficient hours of sleep could increase the risk of accidents and injuries as also lead to self-harm, suicidal thoughts or suicide attempts among teenagers.

Conversely, sleeping for longer hours may also be associated with adverse health outcome such as hypertension, diabetes, obesity and mental health problems.

"Sleep is essential for a healthy life, and it is important to promote healthy sleep habits in early childhood," said Shalini Paruthi from the American Academy of Sleep Medicine, Springfields, Illinois.

A good sleep pattern can lead to better health outcome like improved attention, behaviour, learning, memory, emotional regulation, quality of life, mental and physical health.

"Adequate sleep is essential for the children who are in the critical years of early development," added Nathaniel Watson, President at the American Academy of Sleep Medicine.

At least 12 to 16 hours of sleep per day is imperative for infants (four to 12 months), the researchers recommended.

For children between one to two years of age, 11 to 14 hours sleep is essential, and for those who are three to five years, 10 to 13 hours is needed.

Nine to 12 hours for children between six to 12 years and eight to 10 hours of sleep for teenagers from 13 to 18 years is good for them and their overall health. 

"Making sure there is ample time for sleep is one of the best ways to promote a healthy lifestyle for a child," Paruthi noted.

For the study, published in the Journal of Clinical Sleep Medicine, the team conducted a 10-month project and reviewed 864 published scientific articles addressing the relationship between sleep duration and health in children.​

​New York, June 15 (IANS) Type 2 diabetes may lead to significant changes in the brain's grey matter volume in teenagers, says a study involving an Indian-origin researcher.

Grey matter is the brain region involved in muscle control and sensory perception such as seeing and hearing, memory, emotions, speech, decision-making and self-control.

"Previous studies suggested that youth with Type 2 diabetes have changes in brain structure and poorer cognitive function scores compared to their peers," said Amy Sanghavi Shah, Physician-Scientist at Cincinnati Children's Hospital Medical Centre in the US. 

The findings showed that adolescents with Type 2 diabetes have six regions with significantly less grey matter and three with significantly more. 

Also, a relationship was found between less grey matter volume in the brain and the ability to pronounce and sound out unfamiliar words.

"Preventing Type 2 diabetes in adolescents is important to prevent possible complications in the future," added lead author Jacob Redel from Cincinnati Children's Hospital.

"Our results do not show cause and effect. But studies in adults with Type 2 diabetes with longer duration of disease also show brain volume differences, brain vascular changes and cognitive decline," Redel noted, stressing that the team only found an association between the two.

For the study, the team analysed 20 teenagers with Type 2 diabetes and compared them to 20 teenagers without diabetes who were similar in age, race and sex. 

All participants in the study had high-resolution MRIs. Neither group had prior neurological nor psychological disease or prior abnormal MRIs.

The study was presented at the American Diabetes Association's Scientific Sessions in New Orleans in the US, recently.​