Knowledge Update

​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.​

New York, April 22 (IANS) The way we shop and bargain for fruits and vegetables using our sensory powers, chimpanzees too use manipulative dexterity to evaluate and select figs -- a vital resource when preferred foods are scarce, say researchers.

The study demonstrates the foraging advantages of opposable fingers and careful manual prehension (the act of grasping an object with precision). 

The findings shed new light on the ecological origins of hands with fine motor control, a trait that enabled our early human ancestors to manufacture and use stone tools. 

“The supreme dexterity of the human hand is unsurpassed among mammals, a fact that is often linked to early tool use," said lead author Nathaniel J Dominy, professor of anthropology at Dartmouth College in the US.

For the study, Dominy and his colleagues observed the foraging behaviours of chimpanzees, black-and-white colobus monkeys, red colobus monkeys and red-tailed monkeys in Kibale National Park, Uganda. 

The primates depended on figs. To determine if the green figs are edible, chimpanzees ascend trees and make a series of sensory assessments.

They look at the fig's colour, smell the fig, manually palpate or touch each fig to assess the fruit's elasticity and bite the fig to determine the stiffness of the fruit. 

Colobus monkeys do not have thumbs and evaluate the ripeness of figs by using their front teeth.

The team observed the non-selection, rejection and ingestion of individual figs by chimps and collected specimens of figs.

Based on the sensory data obtained, the team estimated the predictive power that sensory information may have on chimpanzees when estimating the ripeness of figs.

The study, published in the journal Interface Focus, resembles that of humans shopping for fruits and provides new insight into how chimpanzees exhibit advanced visuomotor control during the foraging process and more broadly, on the evolution of skilled forelimb movements.​

​London, April 22 (IANS) As the world celebrated Earth Day on Friday, a team of European researchers has found substantially different climate change impacts on Earth for a global warming of 1.5 degrees Celsius and two degrees Celsius by 2100.

The two temperature limits are included in the Paris climate agreement, researchers said, adding that the additional 0.5 degrees Celsius would mean a 10 cm higher global sea-level rise by 2100, longer heat waves and would result in virtually all tropical coral reefs being at risk. 

"We found significant differences for all the impacts we considered," said Carl Schleussner, lead author of the study published in the journal Earth System Dynamics.

"We analysed the climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report focusing on the projected impacts at 1.5 degrees Celsius and two degrees Celsius warming at the regional level," Schleussner added.

The team considered 11 different indicators including extreme weather events, water availability, crop yields, coral reef degradation and sea-level rise.

With researchers from Germany, Switzerland, Austria and the Netherlands, they identified a number of hotspots around the globe where projected climate impacts at two degrees Celsius are significantly more severe than at 1.5 degrees Celsius. 

In tropical regions, the half-a-degree difference in global temperature could have detrimental consequences for crop yields, particularly in Central America and West Africa. 

On average, local tropical maize and wheat yields would reduce twice as much at 2 degree Celsius compared to a 1.5 Celsius temperature increase.

On a global scale, the researchers anticipate sea level to rise about 50cm by 2100 in a two degrees Celsius warmer world, 10 cm more than for 1.5 degrees Celsius warming. 

"Sea level rise will slow down during the 21st century only under a 1.5 degrees Celsius scenario," noted Schleussner.

"Our study shows that tropical regions -- mostly developing countries that are already highly vulnerable to climate change -- face the biggest rise in impacts between 1.5 degrees Celsius and two degrees Celsius," added William Hare, senior scientist at Climate Analytics, a non-profit climate science and policy institute.​

​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) 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) 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) 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.​