Knowledge Update

​Toronto, April 22 (IANS) After an asteroid impact that killed carnivorous bird-like dinosaurs some 65 million years ago, birds with toothless beaks survived on seeds in the absence of other food sources, say Canadian researchers.

When the dinosaurs became extinct, plenty of small bird-like dinosaurs disappeared along with giants like Tyrannosaurus and Triceratops.

Why only some of them survived to become modern day birds remained a mystery, researchers noted.

"The small bird-like dinosaurs in the Cretaceous -- the maniraptoran dinosaurs -- are not a well understood group. They are some of the closest relatives to modern birds and at the end of the Cretaceous, many went extinct, including the toothed birds but modern crown-group birds managed to survive the extinction," said first author of the study Derek Larson.

The team of researchers investigated whether the extinction at the end of the Cretaceous was an abrupt event or a progressive decline simply capped by the meteor impact. 

Larson and his colleagues looked for patterns of diversity in the teeth, which spanned 18 million years (up until the end of the Cretaceous). 

"The maniraptoran dinosaurs maintained a very steady level of variation through the last 18 million years of the Cretaceous. They abruptly became extinct just at the boundary," Larson said in a paper that appeared in the journal Current Biology.

The team suspected that diet might have played a part in the survival of the lineage that produced today's birds and they used dietary information and previously published group relationships from modern day birds to infer what their ancestors might have eaten. 

Larson and his colleagues hypothesised that the last common ancestor of today's birds was a toothless seed eater with a beak.

"There were bird-like dinosaurs with teeth up until the end of the Cretaceous, where they all died off very abruptly," said Larson, adding, "Some groups of beaked birds may have been able to survive the extinction event because they were able to eat seeds."​

​New York, April 22 (IANS) Although a combination of antiretroviral therapies has led to a decrease in the mortality rates in people with HIV infection, a new study has found that these patients often show signs of premature ageing.

Researchers discovered that the HIV-virus infection prematurely advances the human biological ageing process on an average by five years.

This further propels the onset of age-related diseases like cardiovascular disease, neurocognitive impairment, and liver problems, thus increasing the risk of mortality by 19 percent.

"The medical issues in treating people with HIV have changed. Now we worry about diseases related to ageing, like cardiovascular disease, neurocognitive impairment, and liver problems," said Howard Fox, professor at University of Nebraska in the US.

Researchers used methylation -- the process by which small chemical groups are attached to DNA -- as a tool to analyse the epigenetic changes in people's cells - that affect the DNA but not the sequence.

Methylation of DNA can impact how genes get translated into proteins.

There was no difference found between the methylation patterns in those people who were recently infected, that is less than five years and those with chronic infection of more than 12 years, the researchers added in the paper published in the journal Molecular Cell.

"We set out to look at the effects of HIV infection on methylation and I was surprised that we found such a strong ageing effect," said another researcher Trey Ideker, professor at University of California-San Diego.

The study included 137 patients in the analysis. Subjects who were chosen didn't have other health conditions that could skew the results. 

"People infected with HIV should be aware that they're of greater risk for age-related diseases and should work to diminish those risks by making healthy lifestyle choices regarding exercise, diet, and drug, alcohol and tobacco use," the researchers suggested.​

London, April 22 (IANS) Gender stereotyping in baby boys and girls may start as young as three months and men recognise gender of the new-born babies based on the pitch of their cries, researchers reveal.

Adults often wrongly assume babies with higher-pitched cries as females and lower-pitched cries are males.

The findings revealed that inspite of no actual difference in pitch between the voices of girls and boys before puberty, the study found that adults make assumptions about the gender of babies based on their cries.

"It is intriguing that gender stereotyping can start as young as three months, with adults attributing degrees of femininity and masculinity to babies solely based on the pitch of their cries,” said David Reby from the University of Sussex in Britain. 

The team recorded the spontaneous cries of 15 boys and 13 girls who were on average four months old and the participating adults were a mixture of parents and non-parents.

They synthetically altered the pitch of the cries while leaving all other features of the cries unchanged to ensure they could isolate the impact of the pitch alone. 

When told the gender of the baby, adults make assumptions about the degree of masculinity or femininity of the baby based on the pitch of the cry.

The results also indicate that men assume that boy babies are in more discomfort than girl babies with the same pitched cry which may indicate that this sort of gender stereotyping is more ingrained in men.

"The research shows that we tend to wrongly attribute what we know about adults -- that men have lower pitched voices than women -- to babies, when, in fact, the pitch of children's voices does not differ between sexes until puberty,” added Nicolas Mathevon from Hunter College in the US in the paper published in the journal BMC Psychology.​

New York, April 20 (IANS) What if you can watch the Earth -- its blue-and-white marbling stark against a black interstellar backdrop -- from space? The experience will sure evoke an intense awe like it happens with astronauts on the International Space Station (ISS).

Researchers from the University of Pennsylvania's positive psychology centre are now studying the phenomenon called the "overview effect" to better understand the emotions astronauts commonly recount when they look at the Blue Marble from space.

“We watch sunsets whenever we travel to beautiful places to get a little taste of this kind of experience. These astronauts are having something more extreme,” said lead researcher David Yaden. 

“By studying the more-extreme version of a general phenomenon, you can often learn more about it,” he added.

To understand the “overview effect”, Yaden and colleagues analysed excerpts from astronauts from all over the world who documented viewing the Earth from space. 

Themes emerged from the quotes, ideas like unity, vastness, connectedness and perception -- in general the sense of an overwhelming, life-changing moment.

The effort is to look at implications for space flight as the aeronautical community heads toward years-long missions to places like Mars and to understand how to induce a similar sensation for non-astronauts.

“We think of people who do a lot of meditation or climb mountains, people who are awe junkies, having these experiences. We don't [often] think of these very strict scientists reporting these blissful moments,” said Yaden in a paper appeared in the journal Psychology of Consciousness. 

They are now planning a follow-up experiment using virtual reality that gives participants the chance to Earth-gaze which could result in an experience similar to the "overview effect".

“In the end, what we care about is how to induce these experiences. They help people in some ways be more adaptive, feel more connected and reframe troubles,” the authors noted.​

​New York, April 21 (IANS) Exposure to chemicals found in everyday products can lead to an increase in body fat which may pose various health hazards, reveals new research.

“Growing research shows that these chemicals could be harming people's health," said lead author Lei Yin, assistant research scientist at University of Georgia.

Levels of phthalates -- class of industrial chemicals used to make food packaging materials, tubing for dairy products and other items used in the production of fast food -- have been found in human fluids in previous studies.

In the study, the team analysed the presence of a specific phthalate, benzyl butyl phthalate (BBP), in the body. 

Phthalate exposure can be closely associated with the rise of different types of disease development. 

Some are known to cause reproductive toxicity at high levels of exposure but the link between low-level exposure and BBP had not yet been thoroughly explored.

"It could be that some chemicals at a very low dose and over a long period time, which is known as chronic exposure, can cause more harmful diseases or effects," Yin explained in the paper published in the journal Toxicology in Vitro.

The team used mouse cells to create in-vitro models to analyse how exposure to BBP affected the way oils and fats, known as lipids, accumulated within the cells.

The results of BBP's effects were compared with bisphenol A or BPA known for its role in development of fat cells.

BBP caused a response in the cells that is similar to BPA. Both chemicals prompted the accumulation of lipid. 

However, the lipids from BBP-treated cells were larger, suggesting that BBP exposure may lead to obesity.

Genetic components can contribute to the development of obesity. "However, environmental exposure may also contribute to obesity," the authors added.​

​New York, April 21 (IANS) In one of the largest studies on the genes involved in human behaviour, a team of over 190 researchers from 140 institutions in 17 countries has found genetic variants associated with our feelings of well-being, depression and neuroticism.

The researchers, however, advise caution when interpreting the results as genetic variants do not determine whether someone develops depressive symptoms, neuroticism or has a poor sense of wellbeing.

“In this paper, we applied advanced statistical analyses and meta-analysed or combined, results across a large number of studies which is the most powerful way to conduct this type of genetics research," said Dr Alexis Frazier-Wood, assistant professor of pediatrics and nutrition at Baylor College of Medicine and Texas Children's Hospital.

“We found three genetic variants associated with subjective well-being -- how happy a person thinks or feels about his or her life. We also found two genes harboring variants associated with depressive symptoms and 11 genes where variation was associated with neuroticism,” explained Dr Frazier-Wood.

How people think and feel about their lives depends on multiple factors, including genes.

“Genetics is only one factor that influences these psychological traits. The environment is at least as important, and it interacts with the genetic effects,” added Dr Daniel Benjamin, associate professor at University of Southern California Dornsife College of Letters, Arts and Sciences and corresponding author.

The information in this report allows researchers to look at possible ways to study these conditions.

“We can start studying the functions of these genes to begin to understand why biologically some people are more predisposed to feel this way than others," said Frazier-Wood in a paper published in the journal Nature Genetics.​

​New York, April 21 (IANS) Want to click that perfect selfie with fuller lips for a flawless pout? Get a lip implant. According to a media report, 2015 set a record of one lip surgery every 19 minutes in the US.

The findings, based on a survey of American Society of Plastic Surgeons (ASPS), showed that in 2015, a total of 27,449 lip implants on both males and females took place -- a jump of 48 percent since 2000, CNBC reported on Tuesday.

"We live in the age of the selfie and because we see images of ourselves almost constantly on social media, we're much more aware of how our lips look," David Song from the American Society of Plastic Surgeons (ASPS) was quoted as saying.

In Britain, a cosmetic dentistry firm has claimed that selfies have also changed the types of smile that patients are asking for.

People are now asking for a new "selfie smile" which "benefits rather than suffers at the hands of the typically center-widening, periphery-narrowing properties of smartphone cameras," the report stated.

"We have seen a 30 percent rise over 5 years in the number of patients sending in selfies through the website with concerns about the look of their front teeth, yet when the patients come in person, often the teeth don't look too bad at all," Tim Bradstock-Smith, a clinical director and cosmetic dentist, was quoted as saying.

"A patient may not be ready to commit to something as dramatic as a facelift or eyelid surgery, but there are a variety of ways you can change the shape of your lips," explained Robert Houser, a plastic surgeon in Ohio, US.

The ASPS commissioned a national survey of around a thousand women and found that the "subtle and sultry lips" of Hollywood actress Jennifer Lawrence were the most attractive celebrity lips that women wanted.​

New York, April 21 (IANS) A team of US scientists has invented a new way to create three-dimensional (3D) human heart tissue from stem cells that offers cheaper and faster method to create heart tissue for testing drugs and modelling disease.

The tissue also opens the door for a precision medicine approach to treating heart disease.

"We have bioengineered micro-scale heart tissues with a method that can easily be reproduced, which will enable scientists in stem cell biology and the drug industry to study heart cells in their proper context," said Nathaniel Huebsch, postdoctoral fellow at San Francisco-based at the Gladstone Institutes.

"In turn, this will enhance our ability to discover treatments for heart disease," Huebsch added.

Creating heart cells from induced pluripotent stem cells (iPSCs) that are derived from a patient's skin cells is inadequate for drug testing because they do not properly predict how a drug will affect adult heart cells.

Additionally, heart cells created from iPSCs are challenging to make and work with, so creating large quantities can be difficult.

The micro-heart muscle addresses these concerns. Forcing the cells to organise and stretch into 3D tissue helps spur development and coaxes them into resembling more mature cells that can better predict how a drug will affect adult heart cells.

The new method, published in the journal Scientific Reports, requires a thousand-fold fewer cells to grow the tissue than other tissue engineering techniques.

Using fewer cells allows the scientists to do many more experiments with the same amount of resources.

"The beauty of this technique is that it is very easy and robust and still allows you to create three-dimensional miniature tissues that function like normal tissues," said senior author Bruce Conklin, senior investigator at Gladstone.

"We think that the micro-heart muscle will provide a superior resource for conducting research and developing therapies for heart disease," he noted.​

Sydney, April 21 (IANS) Do you feel sleepy during daytime at work? Blame it on your love for oily samosas and cheese-laden pizzas -- not to forget a poor night's sleep -- for this.

According to a study, men who consume diets high in fat and sleep less during night time are more likely to feel sleepy during the day.

"After adjusting for other demographic and lifestyle factors and chronic diseases, we found that those who consumed the highest fat intake were more likely to experience excessive daytime sleepiness," said lead author Yingting Cao, doctoral student at University of Adelaide in Australia.

Higher consumption of food items rich in fat was also strongly associated with sleep apnea, a sleep disorder.

"Poor sleep and feeling sleepy during the day means you have less energy, but this, in turn, is known to increase people's cravings for high-fat, high-carbohydrate foods associated with poor sleep outcomes. So the poor diet-and-sleep pattern can become a vicious cycle," Cao explained in the paper published in the journal Nutrients.

Daytime sleepiness may have significant implications for alertness and concentration, the researchers warned, adding that people need to pay more attention to eat better and have a good sleep.

"We hope our work could help to inform future intervention studies, enabling people to achieve healthy weight loss while also improving their quality of sleep," Cao added.

The results were based on data of more than 1800 Australian men aged 35-80 and included their dietary habits over a 12-month period.

Among those with available dietary and sleep data, 41 percent of the men surveyed had reported experiencing daytime sleepiness, while 47 percent of them had poor sleep quality at night.

About 54 percent had mild-to-moderate sleep apnea, and 25 percent had moderate-to-severe sleep apnea.​

Toronto, April 21 (IANS) While planning a visual task, your brain initially reflects the visual goal accurately but errors accumulate during a memory delay and further escalate during the final action, say scientists from York University.

“Think of all the times you see something and plan to act on it but after only a short delay, you make a mistake," said professor Doug Crawford. 

“For example, before my morning coffee kicks in, I'm great at making silly mistakes like putting the honey away in the fridge instead of the peanut butter,” he added.

For the study, led by Amirsaman Sajad in Crawford's visuomotor neuroscience lab, researchers recorded signals in the frontal cortex area of the brain during the delay between target-related visual activity and intended gaze-related motor activity. 

The visual response and memory activity for the time in between was then analysed.

“We looked at what happens from vision to memory to action and how the spatial code changes through time in the frontal cortex,” said Sajad.

“In the Olympics tennis analogy, when a high degree of accuracy is required, a one-second delay in frontal cortex processing could make the difference between an Olympic gold and silver,” Crawford noted.

The findings, published in the journal eNeuro, are of particular significance to research in diseases affecting frontal cortex function “because if errors accumulate in healthy individuals, the accumulations would be much worse with diseases that affect frontal cortex function,” the authors noted.​