Comment

Comment by Dr. Krishna Kumari Challa on January 14, 2017 at 11:13am

Rocks collected during the Apollo 14 mission made researchers finally pinpoint the exact age of the Moon, and it turns out, our lunar neighbour is an incredible 4.51 billion years old.

These findings suggest that the Moon was formed roughly 60 million years after the Solar System first formed, making it up to 140 million years older than previous estimates.

The reason we've never been able to accurately date the age of the Moon in the past is that there's very few well-preserved Moon rocks left on its surface.

Most of the rocks brought back by Apollo astronauts are breccias - mixes of different rocks that have been mashed together by the meteorite strikes that plague the Moon, thanks to its lack of atmosphere.

So instead of trying to find chunks of rock that had been there since the early days, the team instead turned to zircon - a mineral that would have formed as the Moon was cooling from its fresh, molten state into the rocky satellite we see today.

Once formed, zircon crystals stay perfectly intact as little time signatures of geological events. Studying zircon allows researchers to see when parts of the rock solidified, which is exactly what they needed to figure out when the Moon had fully formed.

This mineral is just the king when you try to understand any processes, because it is amazingly sturdy.

The team performed a process known as uranium-lead dating on zircon samples that were extracted from the Apollo 14 space rocks.

This required them to liquefy the zircon samples in acid, destroying the space rock artefacts.

But inside the zircon, the team was able to pull out four different elements: uranium, lead, lutetium, and hafnium.

Since uranium - a radioactive element - eventually turns into lead after long periods of time, the researchers could analyse how long the lead had been forming, giving them an accurate date of the Moon’s birth.

The ratios of lutetium and hafnium in the zircon also indicated how long the mineral had been around for.

Combining these analytical techniques, the team found that the Moon is 4.51 billion years old, making it far older than we previously thought, and providing us with a more accurate picture of how our Solar System formed.

Comment by Dr. Krishna Kumari Challa on January 14, 2017 at 11:08am

The toll fetal alcoholic syndrome takes...

Worldwide, an estimated 1,19,000 children are born with Fetal Alcohol Syndrome (FAS) each year, a new study from the Centre for Addiction and Mental Health (CAMH) shows.

The study, published in The Lancet Global Health, provides the first-ever estimates of the proportion of women who drink during pregnancy, as well as estimates of FAS by country, World Health Organization (WHO) region and worldwide.

Globally, nearly 10 per cent of women drink alcohol during pregnancy, with wide variations by country and WHO region. In some countries, more than 45 per cent of women consume alcohol during pregnancy.

Nearly 15 per 10,000 people around the world are estimated to have FAS, the most severe form of Fetal Alcohol Spectrum Disorder (FASD). FAS is characterized by mental, behavioural and learning problems, as well as physical disabilities. Not every woman who drinks while pregnant will have a child with FAS. "We estimated that one in 67 mothers who drink during pregnancy will deliver a child with FAS," says lead author Dr. Svetlana Popova, Senior Scientist in CAMH's Institute for Mental Health Policy Research.

Although it's well established that alcohol can damage any organ or system in the developing fetus, particularly the brain, it's still not known exactly what makes a fetus most susceptible, in terms of the amount or frequency of alcohol use, or timing of drinking during pregnancy. Other factors, such as the genetics, stress, smoking and nutrition also contribute to the risk of developing FASD.

"The safest thing to do is to completely abstain from alcohol during the entire pregnancy," says Dr. Popova.

Comment by Dr. Krishna Kumari Challa on January 13, 2017 at 9:12am

Hair cells could heal wounds without scars forming...

Scientists found that in mouse during wound healing adipocytes regenerate from myofibroblasts, a cell type thought to be differentiated and non-adipogenic. Myofibroblast reprogramming required neogenic hair follicles, which triggered BMP signaling and then activation of adipocyte transcription factors expressed during development. Overexpression of the BMP antagonist, noggin, in hair follicles or deletion of the BMP receptor in myofibroblasts prevented adipocyte formation. Adipocytes formed from human keloid fibroblasts when treated with either BMP or when placed with human hair follicles in vitro. Thus, they identified the myofibroblast as a plastic cell type that may be manipulated to treat scars in humans.

http://science.sciencemag.org/content/early/2017/01/04/science.aai8792

Comment by Dr. Krishna Kumari Challa on January 12, 2017 at 7:09am

Another theory on how the moon came into existence...

Our moon formed about 4.5 billion years ago, between twenty million and a hundred million years after Earth took shape. How exactly it formed is a matter of debate. Did it accrete in tandem with Earth, from the same proto-planetary stuff, or did it spin off afterward? Is it our fraternal twin or an identical one? Or was it adopted, drawn into our gravitational sway as it passed by? Since the nineteen-eighties, the consensus has centered on the single-impact hypothesis, sometimes known as the Big Splash or the Big Splat, which supposes that the moon formed when a planet-size object, often called Theia, crashed into Earth and sent a huge mass of debris into orbit. But today, in a paper in Nature Geoscience, a team of Israeli researchers is proposing an equally compelling origin story: the moon, they say, is the product not of one impact but of at least a dozen—and it isn’t just one moon but an amalgam of the many moons that came before it.

Comment by Dr. Krishna Kumari Challa on January 6, 2017 at 9:34am

Carbon Chemistry: What is new...Carbon can exceed four-bond limit

A molecule originally proposed more than 40 years ago breaks the rules about how carbon connects to other atoms, scientists have confirmed. In this unusual instance, a carbon atom bonds to six other carbon atoms. That structure, mapped for the first time using X-rays, is an exception to carbon’s textbook four-friend limit, researchers report in the Jan. 2 Angewandte Chemie.

Atoms bond by sharing electrons. In a typical bond two electrons are shared, one from each of the atoms involved. Carbon has four such sharable electrons of its own, so it tends to form four bonds to other atoms.

But that rule doesn’t always hold. In the 1970s, German scientists made an unusual discovery about a molecule called hexamethylbenzene. This molecule has a flat hexagonal ring made of six carbon atoms. An extra carbon atom sticks off each vertex of the ring, like six tiny arms. Hydrogen atoms attach to the ring’s arms. And leftover electrons zip around the middle of the ring, strengthening the bonds and making the molecule more stable. 

When the scientists removed two electrons from the molecule, leaving it with a positive charge, some evidence suggested it might dramatically change its shape. It seemed to rearrange so that one carbon atom was bonded to six other carbons.

A  different lab has revisited the question. 

When hexamethylbenzene lost two electrons, it reordered itself. One carbon atom jumped out of the ring and took a new position on top, turning the flat hexagonal ring into a five-sided carbon pyramid. And the carbon on top of the pyramid was indeed bonded to six other carbons — five in the ring below, and one above.

This molecule is very exceptional. Though scientists have found other exceptions to carbon’s four-bond limit, this is the first time carbon has been shown associating with this many other carbon atoms.

When scientists measured the length of the molecule’s chemical bonds, the top carbon’s six bonds were each a bit longer than an ordinary carbon-carbon bond. A longer bond is generally less strong. So by picking more partners, that carbon has a slightly weaker connection to each one.

The carbon isn’t making six bonds in the sense that we usually think of a carbon-carbon bond as a two-electron bond. That’s because the carbon atom still has only four electrons to share. As a result, it spreads itself a bit thin by sharing electrons among the six bonds.

Comment by Dr. Krishna Kumari Challa on January 6, 2017 at 9:01am

People who live near roads laden with heavy traffic face a higher risk of developing dementia than those living further away, possibly because pollutants get into their brains via the blood stream, according to researchers in Canada.

A study in The Lancet medical journal found that people who lived within 50 metres (55 yards) of high-traffic roads had a 7.0 percent higher chance of developing dementia compared to those who lived more than 300 metres away from busy roadways.

Air pollutants can get into the blood stream and lead to inflammation, which is linked with cardiovascular disease and possibly other conditions such as diabetes. This study suggests air pollutants that can get into the brain via the blood stream can lead to neurological problems.

Comment by Dr. Krishna Kumari Challa on January 5, 2017 at 8:57am

Disturbing facts: Approximately half of studies published on new medical treatments leave out at least some of the adverse effects they uncovered, according to a recent analysis in PLOS Medicine. A team of British researchers conducted the review after coming across individual cases of missing side effects in medical literature, which includes studies from pharmaceutical companies, hospitals and academics. To determine how widespread the problem was, they analyzed 28 journal articles that together cross-checked the published data from more than 500 clinical studies with their original data sets. The review's results quantitatively confirm that some drugs may have side effects not even doctors know about—which means treatments may not be as safe as they appear.

• These findings suggest that researchers should search beyond journal publications for information on side effects of treatments.
• These findings also support the need for the drug industry to release full data on side effects so that a complete picture can be given to health professionals, policy makers, and patients.

http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pm...

Reporting of Adverse Events in Published and Unpublished Studies of Health Care Interventions: A Systematic Review

Comment by Dr. Krishna Kumari Challa on January 5, 2017 at 7:02am

Comment by Dr. Krishna Kumari Challa on January 3, 2017 at 7:41am

Languages Are Still a Major Barrier to Global Science

A third of new scientific findings are published in languages other than English, contributing to biases in our understanding and hinderances to the advance of science and research, a new study has found.

English is now considered the common language of global science. All major scientific journals seemingly publish in English, despite the fact that their pages contain research from across the globe.

Language hinders new findings getting through to practitioners in the field and causes the international community missing important science, said researchers from the University of Cambridge in the UK.

They argue that whenever science is only published in one language, barriers to the transfer of knowledge are created.

The researchers call on scientific journals to publish basic summaries of a studys key findings in multiple languages and universities to encourage translations as part of their outreach evaluation criteria.

The researchers point out an imbalance in knowledge transfer in countries where English is not the mother tongue - much scientific knowledge that has originated there is available only in English and not in their local languages.

Researchers surveyed the web platform Google Scholar in a total of 16 languages for studies on biodiversity conservation published during a single year, 2014.

Of the over 75,000 documents, including journal articles, books and theses, some 35.6 per cent were not in English.

Of these, the majority was in Spanish (12.6 per cent) or Portuguese (10.3 per cent). Simplified Chinese made up six per cent and three per cent were in French.

Random sampling showed that only around half of non-English documents included titles or abstracts in English.

This means that around 13,000 documents on conservation science published in 2014 are unsearchable using English keywords.

This can result in sweeps of current scientific knowledge - known as systematic reviews - being biased towards evidence published in English, researchers said.

This, in turn, may lead to over-representation of results considered positive or statistically significant, and these are more likely to appear in English language journals deemed high-impact.

In addition, information on areas specific to countries where English is not the mother tongue can be overlooked when searching only in English.

For environmental science, this means important knowledge relating to local species, habitats and ecosystems - but also applies to diseases and medical sciences.

But native English speakers tend to assume that all the important information is available in English which is not the case in real terms. On the other hand, non-native English speakers tend to think carrying out research in English is the first priority, often ending up ignoring non-English science and its communication.

The research was published in the journal PLOS Biology.

http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbi...

Comment by Dr. Krishna Kumari Challa on December 30, 2016 at 9:55am

Vera Rubin Didn't Discover Dark Matter

https://blogs.scientificamerican.com/guest-blog/vera-rubin-didnt-di...

• ‹ Previous
• 1
• …
• 842
• 843
• 844
• 845
• 846
• …
• 1053
• Next ›
• Page