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Comment by Dr. Krishna Kumari Challa on January 25, 2017 at 6:35am

How Ants Use Vision When Homing Backward

Ants can navigate over long distances between their nest and food sites using visual cues. Recent studies show that this capacity is undiminished when walking backward while dragging a heavy food item. This challenges the idea that ants use egocentric visual memories of the scene for guidance. Can ants use their visual memories of the terrestrial cues when going backward? Recent research results suggest that ants do not adjust their direction of travel based on the perceived scene while going backward. Instead, they maintain a straight direction using their celestial compass. This direction can be dictated by their path integrator  but can also be set using terrestrial visual cues after a forward peek. If the food item is too heavy to enable body rotations, ants moving backward drop their food on occasion, rotate and walk a few steps forward, return to the food, and drag it backward in a now-corrected direction defined by terrestrial cues. Furthermore, ants can maintain their direction of travel independently of their body orientation. It thus appears that egocentric retinal alignment is required for visual scene recognition, but ants can translate this acquired directional information into a holonomic frame of reference, which enables them to decouple their travel direction from their body orientation and hence navigate backward. This reveals substantial flexibility and communication between different types of navigational information: from terrestrial to celestial cues and from egocentric to holonomic directional memories.

http://www.cell.com/current-biology/abstract/S0960-9822(16)31466-X

Comment by Dr. Krishna Kumari Challa on January 18, 2017 at 8:16am

Comment by Dr. Krishna Kumari Challa on January 18, 2017 at 8:07am

World's main list of 'predatory' science publishers vanishes

In 2012, a librarian from the University of Colorado presented research in a field so new he had to name it himself: predatory publishing.

Jeffrey Beall discovered thousands of online science journals that were either willing to publish fake research for cash, or just so inept that they couldn’t tell the good from the bad and published it all.

Beall, who became an assistant professor, drew up a list of the known and suspected bad apples, known simply as Beall’s List. Since 2012, this list has been world’s main source of information on journals that publish conspiracy theories and incompetent research, making them appear real.

But on Sunday, his website went blank. Only the headline, Scholarly Open Access, remains.

Beall is a regular on Twitter, but he hasn’t posted anything there in days. He isn’t answering email (including a message from the Citizen) or telling anyone what happened. Beall’s List had just been updated for 2017.

A Texas firm called Cabell’s, which also works with academic publishers, hinted that Beall was threatened somehow.

Beall has been a polarizing figure, praised for rooting out fakes but sometimes criticized by people who felt he was too broad in his attacks on “open access” journals.  These offer their contents free to readers, and instead charge researchers to publish their work. Most predators use the open access approach, but there are also top-quality open access journals.

He has also been threatened with legal action by publishers he named on his list.

There are cached copies of Beall’s List for both publishers and individual journals, but these are not being updated. As well, Beall kept busy answering questions from confused researchers around the world almost daily.

In his 2017 update, Beall had identified 1,155 suspicious or fake publishers, most of them putting out dozens or even hundreds of online journals.

- Retractionwatch.com

Comment by Dr. Krishna Kumari Challa on January 15, 2017 at 10:51am

Comment by Dr. Krishna Kumari Challa on January 14, 2017 at 11:34am

Nightmare realized: Woman Killed by a Superbug Resistant to Every Available Antibiotic. The bacteria could fend off 26 different drugs!

Public health officials from Nevada are reporting on a case of a woman who died in Reno in September from an incurable infection. Testing showed the superbug that had spread throughout her system could fend off 26 different antibiotics.

“It was tested against everything that’s available in the United States … and was not effective,” said Dr. Alexander Kallen, a medical officer in the Centers for Disease Control and Prevention’s division of health care quality promotion.

The case involved a woman who had spent considerable time in India, yes, you heard it right, and get alarmed, where multi-drug-resistant bacteria are more common than they are in the US. She had broken her right femur — the big bone in the thigh — while in India a couple of years back. She later developed a bone infection in her femur and her hip and was hospitalized a number of times in India in the two years that followed. Her last admission to a hospital in India was in June of last year.

The unnamed woman — described as a resident of Washoe County who was in her 70s — went into hospital in Reno for care in mid-August, where it was discovered she was infected with what is called a CRE — carbapenem-resistant enterobacteriaceae. That’s a general name to describe bacteria that commonly live in the gut that have developed resistance to the class of antibiotics called carbapenems — an important last-line of defense used when other antibiotics fail. CDC Director Dr. Tom Frieden has called CREs “nightmare bacteria” because of the danger they pose for spreading antibiotic resistance.

In the woman’s case, the specific bacteria attacking her was called Klebsiella pneumoniae, a bug that often causes of urinary tract infections.

Testing at the hospital showed resistance to 14 drugs — all the drug options the hospital had. A sample was sent to the CDC in Atlanta for further testing, which revealed that nothing available to US doctors would have cured this infection.

The woman in Nevada was cared for in isolation; the staff who treated her used infection control precautions to prevent spread of the superbug in the hospital.

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.

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