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Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 8:57am

Making sense of at which direction and at what speed a car is moving may not be possible without the interpretation of the brain, but processing of some of these information starts right at the retinas of the eyes.

Researchers have now explained how the various types of cells in the retina are wired to help the eyes detect the direction and speed of moving objects.

"The wiring diagram represents only a tiny proportion of the total number of connections on the retina," said Sebastian Seung, a computational neuro scientist at Massachusetts Institute of Technology in the US.

To understand how cells are wired together in the retina, the researchers analysed high-resolution electron microscope images of a mouse retina with the help of nearly 2,200 members of EyeWire, an online 'citizen-science' game set up to help with brain-mapping efforts.
To understand how cells are wired together in the retina, the researchers analysed high-resolution electron microscope images of a mouse retina with the help of nearly 2,200 members of EyeWire, an online 'citizen-science' game set up to help with brain-mapping efforts.

Players traced the pathways through the layers of cells to create a high-resolution wiring diagram of part of the retina.

The reconstructed map showed that while one type of bipolar cell (that transmit signals from the photoreceptors to the ganglion cells) connects to the amacrine cells (responsible for 70 percent of input to retinal ganglion cells) filaments close to the cell body, another does do so farther away along the length of the filaments.

The bipolar cells that connect closer to the starburst amacrine cell bodies are known to relay their messages with a time delay, whereas the others transmit their immediately, the researchers discovered.

Because of the lag in the first type of connection, signals that hit two nearby locations on the retina at two slightly different times - as would happen when an object moves across the visual field - could reach the same amacrine-cell filament at the same time.

According to the researchers, the following could help explain how the retina detects motion: The amacrine cell might fire only when it receives this combined information, signalling that something is moving in the direction of the filament.

Stimuli not moving in the direction of the filament would produce impulses that reach the amacrine cell at different times, so that it would not fire.

The study appeared in the journal Nature.

Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 8:36am

How volcanoes erupt: Using friction experiments, University of Liverpool scientists have shown that frictional melting plays a role in determining how a volcano will erupt.
Volcanologists from the University of Liverpool have discovered how lava dome volcanoes erupt. This could help develop methods on predicting how volcanoes will act.

The process of frictional melting determines how the volcano will erupt. The speed of the lava rise and how much friction it creates is determined by this process. Within the lava dome the magma and rocks melt as they rub together by the intense heat. This creates a method called ‘stick-slip’ when the magma adheres to the rocks and stops moving upward until pressure builds — when enough pressure builds up, the magma moves upward again. This process continues until the magma reaches the mouth of the volcano in an eruption.

By studying the stick-slip process, a research team, led by University of Liverpool volcanologist Dr. Jackie Kebdrick, has conducted experiments that could help predict eruptions.

The researchers analyzed lava collected from Mount St. Helens in the United States and the Soufriere Hills volcano in Montserrat. Remnants of pseudotachylyte, which is a cooled friction melt, were found. The study also revealed the process takes place in the conduit leading to the top of the volcano before its eruption.

“The closer we get to understanding the way magma behaves, the closer we will get to the ultimate goal: predicting volcanic activity when unrest begins. Whilst we can reasonably predict when a volcanic eruption is about to happen, this new knowledge will help us to predict how the eruption will behave. With a rapidly growing population inhabiting the flanks of active volcanoes, understanding the behaviour of lava domes becomes an increasing challenge for volcanologists.
http://www.redorbit.com/news/science/1113137915/volcanic-eruption-p...

Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 7:05am

Some e-cigarettes deliver a puff of carcinogens
Electronic cigarettes appear to be safer than ordinary cigarettes for one simple — and simply obvious — reason: People don't light up and smoke them.

With the e-cigarettes, there is no burning tobacco to produce myriad new chemicals, including some 60 carcinogens.

But new research suggests that, even without a match, some popular e-cigarettes get so hot that they, too, can produce a handful of the carcinogens found in cigarettes and at similar levels.

A study to be published this month in the journal Nicotine and Tobacco Research found that the high-power e-cigarettes known as tank systems produce formaldehyde, a known carcinogen, along with the nicotine-laced vapour that their users inhale. The toxin is formed when liquid nicotine and other e-cigarette ingredients are subjected to high temperatures, according to the study. A second study that is being prepared for submission to the same journal points to similar findings.

The long-term effects of inhaling nicotine vapour are unclear, but there is no evidence to date that it causes cancer or heart disease as cigarette smoking does. Indeed, many researchers agree that e-cigarettes will turn out to be much safer than conventional cigarettes, an idea that e-cigarette companies have made much of in their advertising. The website for Janty, a company that manufactures popular tank systems, says the benefits of e-cigarettes include having "no toxins associated with tobacco smoking."

Nonetheless, the new research suggests how potential health risks are emerging as the multibillion-dollar e-cigarette business rapidly evolves, and how regulators are already struggling to keep pace. While the Food and Drug Administration last month proposed sweeping new rules that for the first time would extend its authority to e-cigarettes, the FDA has focused largely on what goes into these products — currently, an unregulated brew of chemicals and flavourings — rather than on what comes out of them, as wispy plumes of flavoured vapour.
This finding suggests that in certain conditions," e-cigarettes "might expose their users to the same or even higher levels of carcinogenic formaldehyde as tobacco smoke.

Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 6:50am

Odors define us, yet the scientific zeitgeist is that we don’t communicate through pheromones—scents that influence behavior. A new study challenges that thinking, finding that scent can change whether we think someone is masculine or feminine.

Humans carry more secretion and sweat glands in their skin than any other primate. Yet 70% of people lack a vomeronasal organ, a crescent-shaped bundle of neurons at the base of each nostril that allows a variety of species—from reptiles to nonprimate mammals—to pick up on pheromones. (If you’ve ever seen your cat huff something, he’s using this organ.) Still, scientists have continued to hunt for examples of pheromones that humans might sense.

Two strong candidates are androstadienone (andro) and estratetraenol (estra). Men secrete andro in their sweat and semen, while estra is primarily found in female urine. Researchers have found hints that both trigger arousal—by improving moods and switching on the brain’s “urge” center, the hypothalamus—in the opposite sex. Yet to be true pheromones, these chemicals must shape how people view different genders.

That’s exactly what they do, researchers from the Chinese Academy of Sciences in Beijing report online today in Current Biology.
http://bcove.me/qupsica9
http://news.sciencemag.org/biology/2014/05/man-or-woman-trust-your-...

Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 6:46am

Put science before emotion over radioactive waste
http://bismarcktribune.com/news/columnists/put-science-before-emoti...

Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 6:43am

Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 6:40am

Young blood may reverse ageing : Researchers think it may contain natural chemicals that turn back the clock to rejuvenate the ageing brain
Scientists have shown that an infusion of young blood can reverse signs of ageing. Although the experiment was conducted on laboratory mice, the next step could involve a study of elderly humans.
In the study, blood from three-month-old mice was repeatedly injected into 18-month-old mice near the end of their natural life span. The "vampire therapy" improved the performance of the elderly mice in memory and learning tasks. Structural, molecular and functional changes were also seen in their brains.

Writing in the journal Nature Medicine, the US team led by Dr Tony Wyss-Coray, from Stanford University, said: "Our data indicate that exposure of aged mice to young blood late in life is capable of rejuvenating synaptic plasticity and improving cognitive function.

"Future studies are warranted in aged humans and potentially those suffering from age-related neurodegenerative disorders."
Evidence was seen of new connections forming in the hippocampus, a brain region vital to memory and sensitive to ageing.

Ageing mice given eight infusions of young blood over three weeks improved their performance in mental tests. Infusions of blood from other elderly mice had no effect.

What caused the changes is still unknown, but it appears to involve activation of a protein called Creb in the hippocampus that helps regulate certain genes.

The scientists wrote: "One possibility is that introducing 'pro-youthful' factors from aged blood can reverse age-related impairments in the brain, and a second possibility is that abrogating pro-ageing factors from aged blood can counteract such impairments.These two possibilities are not mutually exclusive, warrant further investigation, and may each provide a successful strategy to combat the effects of ageing."

Dr Eric Karran, from the dementia charity Alzheimer's Research UK, described the results as "interesting", but added that the study "does not investigate the type of cognitive impairment that is seen in Alzheimer's disease".

Comment by Dr. Krishna Kumari Challa on May 6, 2014 at 5:48am

MERS is a respiratory virus, known initially as novel coronavirus (CoV). Until now, it has largely been confined to the Middle East, having been first discovered in Saudi Arabia in 2012. One possibility is that camel meat or raw camel milk might be one route of transmission. fruit bats are increasingly thought to be the reservoir for MERS—specifically, the Egyptian tomb bat.
SARS (Severe acute respiratory syndrome coronavirus), which is a cousin to MERS, caused a major worldwide epidemic in 2003, infecting more than 8000 and killing almost 10%. SARS caused major infections in China, Hong Kong and Toronto, among others, before being contained by unprecedented multinational cooperation and careful infection control, within only about a year. SARS was linked to live animal markets, and specifically to civets.

Animals are often the hidden source of outbreaks, known as zoonoses.

Comment by Dr. Krishna Kumari Challa on May 4, 2014 at 7:50am

Is Lead Poisoning one of the reasons for the Down fall of Ancient Rome?
It is now universally accepted that utilization of lead for domestic purposes and water distribution presents a major health hazard. The ancient Roman world was unaware of these risks. How far the gigantic network of lead pipes used in ancient Rome compromised public health in the city is unknown. Lead isotopes in sediments from the harbor of Imperial Rome register the presence of a strong anthropogenic component during the beginning of the Common Era and the Early Middle Ages. They demonstrate that the lead pipes of the water distribution system increased Pb contents in drinking water of the capital city by up to two orders of magnitude over the natural background. The Pb isotope record shows that the discontinuities in the pollution of the Tiber by lead are intimately entwined with the major issues affecting Late Antique Rome and its water distribution system.
http://www.pnas.org/content/early/2014/04/16/1400097111

http://news.sciencemag.org/archaeology/2014/04/scienceshot-did-lead...

Comment by Dr. Krishna Kumari Challa on May 4, 2014 at 7:16am

How Ancient Egyptians Moved Massive Pyramid Stones
The ancient Egyptians who built the pyramids may have been able to move massive stone blocks across the desert by wetting the sand in front of a contraption built to pull the heavy objects, according to a new study.

Physicists at the University of Amsterdam investigated the forces needed to pull weighty objects on a giant sled over desert sand, and discovered that dampening the sand in front of the primitive device reduces friction on the sled, making it easier to operate. The findings help answer one of the most enduring historical mysteries: how the Egyptians were able to accomplish the seemingly impossible task of constructing the famous pyramids.

To make their discovery, the researchers picked up on clues from the ancient Egyptians themselves. A wall painting discovered in the ancient tomb of Djehutihotep, which dates back to about 1900 B.C., depicts 172 men hauling an immense statue using ropes attached to a sledge. In the drawing, a person can be seen standing on the front of the sledge, pouring water over the sand, said study lead author Daniel Bonn, a physics professor at the University of Amsterdam.
"Egyptologists thought it was a purely ceremonial act," Bonn told Live Science. "The question was: Why did they do it?"

Bonn and his colleagues constructed miniature sleds and experimented with pulling heavy objects through trays of sand.

When the researchers dragged the sleds over dry sand, they noticed clumps would build up in front of the contraptions, requiring more force to pull them across.

Adding water to the sand, however, increased its stiffness, and the sleds were able to glide more easily across the surface. This is because droplets of water create bridges between the grains of sand, which helps them stick together, the scientists said. It is also the same reason why using wet sand to build a sandcastle is easier than using dry sand, Bonn said.

But, there is a delicate balance, the researchers found.

"If you use dry sand, it won't work as well, but if the sand is too wet, it won't work either," Bonn said."There's an optimum stiffness."

The study, published April 29 in the journal Physical Review Letters, may explain how the ancient Egyptians constructed the pyramids.

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