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Wednesday, July 9, 2014

A photograph of Lyuba’s external appearance prior to any internal examination. 
© Francis Latreille
CT scan of LyubaCT images showing a side-by-side comparison of skulls from Lyuba (left) and Khroma, with bones of the front of the skull shown below. 
Image credit: University of Michigan Museum of Paleontology.
Three-dimensional scans of two mummified newborn woolly mammothsrecovered from the Siberian Arctic are revealing previously inaccessible details about the early development of prehistoric proboscideans. The research, conducted in part by American Museum of Natural History Richard Gilder Graduate School student Zachary T. Calamari, also suggest that both animals died from suffocation after inhaling mud. The findings were published July 8 in a special issue of the Journal of Paleontology.
“These two exquisitely preserved baby mammoths are like two snapshots in time,” said Calamari, who began investigating mammoths as an undergraduate at the University of Michigan working with paleontologist Daniel Fisher. “We can use them to understand how factors like location and age influenced the way mammoths grew into the huge adults that captivate us today.” 

Tuesday, July 1, 2014

New Fossil Discovery Supports “Out of Africa” Monkey Dispersal Theory



Just when and how Old World monkeys—a diverse and widespread group that includes macaques, baboons, and leaf monkeys—dispersed out of Africa and into Eurasia has never been fully understood. But a new discovery of a 7-million-year-old monkey fossil is providing important clues.
It was previously thought that at least some of these monkeys may have dispersed into Eurasia over the Mediterranean Basin or Straits of Gibraltar around 6 million years ago. At this time, the Mediterranean Sea dried up, allowing animals to cross between North Africa and Europe.
The newly discovered fossil, however, indicates that Old World monkey dispersal could have taken place through the Arabian Peninsula even before the Messinian Crisis. The fossil, a very small lower molar, was discovered on Abu Dhabi’s Shuwaihat Island in 2009. 

Why hot water freezes faster than cold water


Why hot water freezes faster than cold water
I found an interesting article online explaining why this phenomenon occurs.
Hot water seems to freeze faster than cold water, known as the Mpemba effect. The effect was named after the Tanzanian student who in 1963 noticed that hot ice cream mix freezes faster than a cold one. The effect was first observed by Aristotle in the 4th century BC, then later Francis Bacon and René Descartes. Mpemba published a paper on his findings in 1969.
Theories for the Mpemba effect have included: faster evaporation of hot water, therefore reducing the volume left to freeze; formation of a frost layer on cold water, insulating it; and different concentrations of solutes such as carbon dioxide, which is driven off when the water is heated. Unfortunately the effect doesn’t always appear - cold water often does actually freeze faster than hot, as you would expect. But this Mpemba effect occurs regularly, and no one has ever been able to definitively answer why.
Now a team of physicists from the Nanyang Technological University in Singapore, led by Xi Zhang, have found evidence that it is the chemical bonds that hold water together that provide the effect. Each water molecule is composed of one oxygen atom bonded covalently to two hydrogen molecules. These bonds involve atoms sharing electrons and are well understood. The separate water molecules are also bound together by weaker forces generated by hydrogen bonds. These forces occur when a hydrogen atom from one molecule of water sits close to an oxygen atom from another.
The team now suggest it is these bonds that cause the Mpemba effect. They propose that when the water molecules are brought into close contact, a natural repulsion between the molecules causes the covalent bonds to stretch and store energy. When the liquid warms up, the hydrogen bonds stretch as the water gets less dense and the molecules move further apart. 
The stretching in the hydrogen bonds allows the covalent bonds to relax and shrink somewhat, which causes them to give up their energy. The process of covalent bonds giving up their energy is essentially the same as cooling, and so warm water should in theory cool faster than cold. The team’s calculations suggest that the magnitude of the covalent bond relaxation accounts for the experimental differences in the time it takes for hot and cold water to freeze.

Saturday, June 21, 2014

A novel way to end the superbug reign

A novel way to end the superbug reign

A team of researchers from the University of East Anglia, in the UK, have found a weak spot in the outer membrane of gram-negative bacteria. These bacteria are found in our gastrointestinal tract, and due to the wide misuse of antibiotics, some are now antibiotic-resistant.
These superbugs can cause a variety of ailments that range from blood infection to pneumonia and meningitis. Changjiang Dong, the leading researcher, told Wired UK: “These drug resistance numbers increase every year, making antibiotics useless, which results in hundreds and thousands of patient’s deaths.” 
But now Dong and his team found out that they can be killed. They found that these bacteria use two proteins, Lpt D and E, to create their outer membrane. The solution is simply to block the path for these proteins, rendering the superbugs unable to defend themselves. 
This works opens up a whole new pathway for the development of drugs that can stop superbugs.
“The really exciting thing about this research is that new drugs will specifically target the protective barrier around the bacteria, rather than the bacteria itself,” said Dong in a news release. “Because new drugs will not need to enter the bacteria itself, we hope that the bacteria will not be able to develop drug resistance in future.” 
The results of this study were published in the journal Nature.

Researchers have discovered that algae in low-light conditions are able to switch a quantum behavior off and on during photosynthesis.

Researchers have discovered that algae in low-light conditions are able to switch a quantum behavior off and on during photosynthesis.
The team led by scientists from the University of New South Wales in Australia suspect this could help the algae harvest energy from the Sun more efficiently.
The phenomenon is quantum coherence. A system that is coherent - with all quantum waves in step with each other - can exist in many different states at once, an effect known as superposition.
Usually scientists only see this behaviour occurring the lab, but the scientists were surprised to find that the transfer of energy between molecules in the light harvesting systems of two different algae was coherent.
The work was done on cryptophytes, single-celled organisms that live at the bottom of pools of water or under thick ice, in very low levels or light.
Learning more about why these algae switch quantum coherence on and off could lead to technological advances, such as better organic solar cells and quantum-based electronic devices. The research is published in the journal Proceedings of the National Academy of Sciences.
Read more:

Meet the Inch Worm From Hell: the Predatory Hawaiian Caterpillar

Meet the Inch Worm From Hell: the Predatory Hawaiian Caterpillar
The Predatory Hawaiian Caterpillar (Eupithecia orichloris) has evolved to fulfill a niche normally occupied by insects like praying mantises. Since there aren’t any on the islands of Hawaii, something had to step up and become a super insectivorous predator. This guy! It blends in almost to perfection amongst the dense foliage of its habitat and waits patiently until an unsuspecting insect wanders by. You see, these Predatory Caterpillar’s have long, thin appendages on their abdomen which act as sensory organs. When something touches these sensory appendages, the sinister caterpillar will bend back and quickly strike the confused insect. To make matters worse (for the insect) these guys are equipped with raptor-like claws to tightly constrain their squirming meals. The little animation below shows just how deadly these things can be.

Neuroscience’s New Toolbox

With the invention of optogenetics and other technologies, researchers can investigate the source of emotions, memory, and consciousness for the first time.
What might be called the “make love, not war” branch of behavioral neuroscience began to take shape in (where else?) California several years ago, when researchers in David J. Anderson’s laboratory at Caltech decided to tackle the biology of aggression. They initiated the line of research by orchestrating the murine version of Fight Night: they goaded male mice into tangling with rival males and then, with painstaking molecular detective work, zeroed in on a smattering of cells in the hypothalamus that became active when the mice started to fight.
The hypothalamus is a small structure deep in the brain that, among other functions, coördinates sensory inputs—the appearance of a rival, for example—with instinctual behavioral responses. Back in the 1920s, Walter Hess of the University of Zurich (who would win a Nobel in 1949) had shown that if you stuck an electrode into the brain of a cat and electrically stimulated certain regions of the hypothalamus, you could turn a purring feline into a furry blur of aggression. Several interesting hypotheses tried to explain how and why that happened, but there was no way to test them. Like a lot of fundamental questions in brain science, the mystery of aggression didn’t go away over the past century—it just hit the usual empirical roadblocks. We had good questions but no technology to get at the answers.
By 2010, Anderson’s Caltech lab had begun to tease apart the underlying mechanisms and neural circuitry of aggression in their pugnacious mice. Armed with a series of new technologies that allowed them to focus on individual clumps of cells within brain regions, they stumbled onto a surprising anatomical discovery: the tiny part of the hypothalamus that seemed correlated with aggressive behavior was intertwined with the part associated with the impulse to mate. That small duchy of cells—the technical name is the ventromedial hypothalamus—turned out to be an assembly of roughly 5,000 neurons, all marbled together, some of them seemingly connected to copulating and others to fighting.
“There’s no such thing as a generic neuron,” says Anderson, who estimates that there may be up to 10,000 distinct classes of neurons in the brain. Even tiny regions of the brain contain a mixture, he says, and these neurons “often influence behavior in different, opposing directions.” In the case of the hypothalamus, some of the neurons seemed to become active during aggressive behavior, some of them during mating behavior, and a small subset—about 20 percent—during both fighting and mating.
That was a provocative discovery, but it was also a relic of old-style neuroscience. Being active was not the same as causing the behavior; it was just a correlation. How did the scientists know for sure what was triggering the behavior? Could they provoke a mouse to pick a fight simply by tickling a few cells in the hypothalamus?

Chitika