Asteroid Craters On Earth Give Clues in Search for Life On Mars

Craters made by asteroid impacts may be the best place to look for signs of life on other planets, a study suggests. Tiny organisms have been discovered thriving deep underneath a site in the US where an asteroid crashed some 35 million years ago.

Scientists believe that the organisms are evidence that such craters provide refuge for microbes, sheltering them from the effects of the changing seasons and events such as global warming or ice ages.

Life forms

The study suggests that crater sites on Mars may also be hiding life, and that drilling beneath them could lead to evidence of similar life forms.

Researchers from the University of Edinburgh drilled almost 2 km below one of the largest asteroid impact craters on Earth, in Chesapeake Bay, US.

Samples from below ground showed that microbes are unevenly spread throughout the rock, suggesting that the environment is continuing to settle 35 million years after impact.

Microbe nutrients

Scientists say that heat from the impact of an asteroid collision would kill everything at the surface.

However, fractures to rocks deep below would enable water and nutrients to flow in and support life.

Some organisms grow by absorbing elements such as iron from rock.

The research was published in the journal Astrobiology.

Read more at Science Daily

Magnetic Fields Can Send Particles to Infinity

Researchers from the Complutense University of Madrid (UCM, Spain) have mathematically shown that particles charged in a magnetic field can escape into infinity without ever stopping. One of the conditions is that the field is generated by current loops situated on the same plane.

At the moment this is a theoretical mathematical study, but two researchers from UCM have recently proved that, in certain conditions, magnetic fields can send particles to infinity, according to the study published in the journal Quarterly of Applied Mathematics.

"If a particle 'escapes' to infinity it means two things: that it will never stop, and "something else," Antonio Diaz-Cano, one of the authors, explained. Regarding the first, the particle can never stop, but it can be trapped, doing circles forever around a point, never leaving an enclosed space.

However, the "something else" goes beyond the established limits. "If we imagine a spherical surface with a large radius, the particle will cross the surface going away from it, however big the radius may be" the researcher declares.

Scientists have confirmed through equations that some particles can escape infinity. One condition is that the charges move below the activity of a magnetic field created by current loops on the same plane. Other requirements should also be met: the particle should be on some point on this plane, with its initial speed being parallel to it and far away enough from the loops.

"We are not saying that these are the only conditions to escape infinity, there could be others, but in this case, we have confirmed that the phenomenon occurs," Diaz-Cano states. "We would have liked to have been able to try something more general, but the equations are a lot more complex."

In any case, the researchers recognise that the ideal conditions for this study are "with a magnetic field and nothing else." Reality always has other variables to be considered, such as friction and there is a distant possibility of going towards infinity.

Nonetheless, the movement of particles in magnetic fields is a "very significant" problem in fields such as applied and plasma physics. For example, one of the challenges that the scientists that study nuclear energy face is the confinement of particles to magnetic fields.

Read more at Science Daily

Hubble Captures Incredible New Panorama of Tarantula Nebula

Millions of young stars shine brightly in this enormous stellar nursery at the heart of the Tarantula Nebula.

The Hubble space telescope captured this amazing panorama, which reveals intricate details about the expanse known as 30 Doradus. Located about 170,000 light-years away in the Large Magellanic Cloud — a small galaxy orbiting our Milky Way — 30 Doradus is one of the largest and most prolific star-forming regions in our galactic neck of the woods.

The region is so huge that, if it were as close to us as the Orion Nebula (the nearest stellar nursery to Earth, about 1,300 light-years away), it would be the size of 60 full moons in the sky and glow so brightly that it could cast shadows on the ground.

Though 30 Doradus isn’t quite that close, Hubble can still resolve the individual stars inside the region, allowing astronomers to study the lives of stars in detail.

Stars are born when a mass of gas and dust collapses under its own weight. The center of this mass gravitationally attracts more material, growing larger and heavier. The extra material increases the density and temperature in the central region. Eventually, the mass reaches a critical point and hydrogen will begin fusing into helium. The star ignites, releasing copious amounts of heat and energy.

Inside 30 Doradus, Hubble can spot stellar babies, only a few thousand years old and still wrapped in the remnants of the dusky cloud of gas that gave rise to them. It can also see massive stars a few tens of millions of years old, which burn through their fuel fast and die young.

The white region in the left side of the picture contains some of the most massive stars in the universe, weighing in at hundreds of times the sun’s mass. This stellar cluster is roughly 2 million to 3 million years old and contains about 500,000 stars in total. Intense ultraviolet light released by the young stars pushes against the surrounding gas and dust, carving out the beautiful structures and filigrees seen in this image. Some of this gas and dust will be mushed together, increasing its density and potentially sparking the birth of more new stars.

Read more at Wired Science

Humans Still Eating Humans

The recent arrest of three people in Brazil suspected of making empanadas out of human flesh (and then selling them) reminds us that though human cannibalism is rare in the modern world, it still persists.

Brazil, in particular, has been linked to cannibalism in recent years. The Lancet journal reported in 1994 “that eating human remains” was common among 250 people who lived in an Olinda slum. “Poverty and a lack of compliance with laws” were blamed, since the starving individuals were eating human body parts that they found in the Brazilian city’s garbage dump.

“Cannibalism is an ethologic behavior widespread among human primates and non-human primates,” Isabel Cáceres, a paleoecologist at the Universitat Rovira i Virgili, told Discovery News. Cáceres has studied the phenomenon -- going back up to 780,000 years ago in our ancestors.

“Probably, the practice of cannibalism in the genus Homo appears due to lack of resources and competition for territory in critical moments,” she added.

The recent case was apparently a cruel twist on that strategy. The suspects confessed to murdering at least two women, eating parts of their bodies, and using the rest to make meat pies sold in the town of Garanhuns near Sao Paulo.

One quote from one of the suspects also points to other factors. Fifty-one-year old Jorge Beltrao Negroponte told SBT Television, “I did certain things for purification, to protect people and deliver them to God.”

“Up until the late 18th century, the human body was a widely accepted therapeutic agent," said Richard Sugg, a member of the Centre for Seventeenth-Century Studies at Durham University. "The most popular treatments involved flesh, bone, or blood, along with a variety of moss sometimes found on human skills.”

In a paper for the Lancet, Sugg shared how a Franciscan monk in the 17th century made marmalade out of human blood, and even wrote a recipe for it. The instructions, in part, read: “stir it to a batter with a knife…pound it…through a sieve of finest silk.”

Sugg also mentioned how the word “mummy” in early-modern texts frequently refers to flesh from mummified human bodies, which were “applied topically or mixed into drinks,” since “this was a common remedy for bruising in the period.” The French King Francis (1494-1547) even carried mummified human flesh “in his purse,” according to Sugg, as a sort of good luck charm.

Opponents of this so-called “corpse medicine” began to emerge in the 16th century. By the late 18th century, hostility toward it became widespread and effective. The folklore about it, however, may persist in certain cultures, and not just due to health reasons.

“Thinking like past humans, without our present day tabu and social behavior that does not allow us to eat other humans and see this as a disgusting action, cannibalism could be observed as a clever strategy,” Yolanda Fernandez-Jalvo, a paleobiologist at the Museo National de Ciencia Naturales, told Discovery News. She studied cannibalism that occurred some 12,000 years ago at a site called Gough’s Cave in what is now Somerset, England.

“Think that if a member of your group dies (of natural causes), the body can give one day off from hunting, which was always dangerous at the time,” she added. And it could prove to be a “good solution” for disposing of the body “that may attract other dangerous carnivores that may attack the group.”

Read more at Discovery News

One of Earliest Farming Sites in Europe Discovered

University of Cincinnati research is revealing early farming in a former wetlands region that was largely cut off from Western researchers until recently. The UC collaboration with the Southern Albania Neolithic Archaeological Project (SANAP) will be presented April 20 at the annual meeting of the Society for American Archaeology (SAA).

Susan Allen, a professor in the UC Department of Anthropology who co-directs SANAP, says she and co-director Ilirjan Gjipali of the Albanian Institute of Archaeology created the project in order to address a gap not only in Albanian archaeology, but in the archaeology in Eastern Europe as a whole, by focusing attention on the initial transition to farming in the region.

"For Albania, there has been a significant gap in documenting the Early Neolithic (EN), the earliest phase of farming in the region," explains Allen. "While several EN sites were excavated in Albania in the '70s and '80s, plant and animal remains - the keys to exploring early farming - were not recovered from the sites, and sites were not dated with the use of radiocarbon techniques," Allen says.

"At that time (under communist leader Enver Hoxha), Albania was closed to outside collaborations and methodologies that were rapidly developing elsewhere in Europe, such as environmental archaeology and radiocarbon dating. The country began forming closer ties with the West following Hoxha's death in 1985 and the fall of communism in 1989, paving the way for international collaborations such as SANAP, which has pushed back the chronology of the Albanian Early Neolithic and helped to reveal how early farmers interacted with the landscape."

The findings show that Vashtëmi, located in southeastern Albania, was occupied around 6,500 cal BC, making it one of the earliest farming sites in Europe. The location of early sites such as Vashtëmi near wetland edges suggests that the earliest farmers in Europe preferentially selected such resource-rich settings to establish pioneer farming villages.

During this earliest phase of farming in Europe, farming was on a small scale and employed plant and animal domesticates from the Near East. At Vashtëmi, the researchers have found cereal-based agriculture including emmer, einkorn and barley; animals such as pigs, cattle and sheep or goats (the two are hard to tell apart for many bones of the skeleton); and deer, wild pig, rabbit, turtle, several species of fish and eels. What seems evident is that the earliest farmers in the region cast a wide net for food resources, rather than relying primarily on crops and domesticated animals, as is widely assumed.

Read more at Science Daily

Chimpanzee Ground Nests Offer New Insight Into Our Ancestors' Descent from the Trees

The first study into rarely documented ground-nest building by wild chimpanzees offers new clues about the ancient transition of early hominins from sleeping in trees to sleeping on the ground. While most apes build nests in trees, this study, published in the American Journal of Physical Anthropology, focused on a group of wild West African chimpanzees that often shows ground-nesting behaviour.

An international team of primatologists from the University of Cambridge and Kyoto University, led by Dr Kathelijne Koops, studied the chimpanzee (Pan troglodytes verus) population in the Nimba Mountains in Guinea, West Africa. All species of great ape build nests to sleep in each night. Construction of these shelters takes minutes as the apes bend, break and interweave branches into a circular frame, followed by tucking in smaller branches to form a sturdy but comfortable sleeping platform.

"We believe that, like modern apes, the common ancestor of chimpanzees and humans also slept in the trees 6 million years ago," said Dr Koops. "However, these nests are not preserved in the fossil or archaeological record, so it is impossible to study directly the ancient transition from sleeping in trees to building shelters on the ground. Recording this rare behaviour in the chimpanzee, our closest relative, may provide vital clues."

As the Nimba chimpanzees do not yet tolerate human presence at close range, the team used new molecular genetic techniques to analyse hairs collected from the nests. This allowed the team to establish the sex of chimpanzees displaying the behaviour and to identify individuals in the group.

The team showed that as chimpanzees sleep both on the ground and in the trees, the transition from trees to the ground did not require a special evolutionary adaptation. This suggests that early hominins may have slept on the ground before the emergence of Homo erectus ('upright man'), the first species which was fully adapted to living on the ground. "This is intriguing as it has long been believed that coming down from the trees was a crucial evolutionary shift," said Koops. "However, this chimpanzees' behaviour suggests a more deep-seated, gradual transition from tree-to-ground sleep."

Other theories for the tree-to-ground transition have included the use of fire and the scarcity of trees in open habitats. The team demonstrated that neither is a prerequisite for ground sleeping, as the chimpanzees live in a plentiful evergreen rainforest and do not create fire.

Read more at Science Daily

Aging Male Giraffes Go Black, Not Gray

Male giraffes become more illustrious with age, but rather than the silvery locks that distinguish the likes of Sean Connery and George Clooney, the hairy blotches on these long-necked mammals darken with age.

And new research suggests the appearance change takes about 1.8 years to complete, with male giraffes being completely covered in coal-black blotches by an average age of 9.4 years.

"What is fascinating about the color change is that it goes from light to dark," study researcher Fred Bercovitch, of the Primate Research Institute and Wildlife Research Center, Kyoto University, told LiveScience. "In gorillas who turn silverback, and in men, the color gets lighter, not darker with age."

Bercovitch and his colleague, local naturalist Phil Berry, analyzed 33 years of data from observations of the Thornicroft’s giraffe (Giraffa camelopardalis thornicroftii), a distinct subspecies endemic to the Luangwa Valley, Zambia. Data included an average of 10-plus years for each giraffe. Overall, they studied 10 males of known age and 26 whose ages were estimated based on the extent of blotch darkening when first observed.

The researchers paid close attention to the color of the spots, which are known to gradually change color from a sienna brown to a coal black, beginning with a darkening in the center of the blotch that slowly extends outward to the edges. (However, nobody had studied the giraffes long enough to pin down the timing of the change until now.)

Bercovitch thinks testosterone somehow drives this color change, though once the bulls reach maturity, and a full set of jet-black spots, the testosterone probably levels out.

With their data on coat-color changes, along with information on male deaths and disappearances, the researchers put together a life-history profile for the subspecies: Males that survive the first year of life become independent from mom by age 2, and leave their natal area at 4 to 8 years old. Coat color starts changing between ages 7 and 8, with about one to two years elapsing before the change is complete.

Males become mature bulls at about 10 years of age and have an average life expectancy of 14 to 16 years. Maximum longevity is about 21 to 22 years, they found.

Read more at Discovery News

Where's the Hottest Place on Earth?

The title of "world's hottest place" is often bestowed upon El Azizia, Libya, where the highest temperature ever measured on Earth was recorded, but a study of satellite temperature data shows that the crown belongs elsewhere, and that it can shift from year to year.

El Azizia took the record for highest temperature ever recorded on Sept. 13, 1922, when a thermometer on a weather station hit a whopping 136 degrees Fahrenheit (58 degrees Celsius), thanks to southerly winds blowing in hot air from over the Sahara Desert. The sweltering temperature displaced the previous record holder of 134 F, measured at the Furnace Creek weather station in Death Valley on July 10, 1913.

But neither of these places, hot though they may be, deserves the banner of "hottest place on Earth," according to new research by a University of Montana team using data from the U.S. Geological Survey's Landsat satellites.

"Most of the places that call themselves the hottest on Earth are not even serious contenders," said team member Steven Running in a NASA statement.

Running and his colleagues examined seven years of infrared data (which indicates temperature) from the Landsat satellites, and found that the winner in five of those years was actually the Lut Desert in Iran.

The reason Lut didn't previously make the list was because "the Earth’s hot deserts — such as the Sahara, the Gobi, the Sonoran and the Lut — are climatically harsh and so remote that access for routine measurements and maintenance of a weather station is impractical," said team member David Mildrexler. "The majority of Earth's hottest spots are simply not being directly measured by ground-based instruments."

Satellites, on the other hand, can get a reading on these hard-to-reach, harsh places because they can scan every piece of the Earth's surface. The satellites take what is called "land skin temperature," which tells the amount of heating of a certain parcel of ground from the sun, the atmosphere and other heat sources. The temperatures measured at weather stations, on the other hands, are taken a couple meters above the ground.

The single highest land skin temperature recorded in any year of the study was found in the Lut Desert in 2005 and measured a stunning 159.3 F (70.7 C). Lut had the highest surface temperature in 2004, 2006, 2007 and 2009 as well.

Read more at Discovery News

New Genes Linked to Brain Size, Intelligence

In the world’s largest brain study to date, a team of more than 200 scientists from 100 institutions worldwide collaborated to map the human genes that boost or sabotage the brain’s resistance to a variety of mental illnesses and Alzheimer’s disease. Published April 15 in the advance online edition of Nature Genetics, the study also uncovers new genes that may explain individual differences in brain size and intelligence.

“We searched for two things in this study,” said senior author Paul Thompson, professor of neurology at the David Geffen School of Medicine at UCLA and a member of the UCLA Laboratory of Neuro Imaging. “We hunted for genes that increase your risk for a single disease that your children can inherit. We also looked for factors that cause tissue atrophy and reduce brain size, which is a biological marker for hereditary disorders like schizophrenia, bipolar disorder, depression, Alzheimer’s disease and dementia.”

Three years ago, Thompson’s lab partnered with geneticists Nick Martin and Margaret Wright at the Queensland Institute for Medical Research in Brisbane, Australia; and with geneticist Barbara Franke of Radboud University Nijmegen Medical Centre in the Netherlands. The four investigators recruited brain-imaging labs around the world to pool their brain scans and genomic data, and Project ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) was born.

“Our individual centers couldn’t review enough brain scans to obtain definitive results,” said Thompson, who is also a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA. “By sharing our data with Project ENIGMA, we created a sample large enough to reveal clear patterns in genetic variation and show how these changes physically alter the brain.”

In the past, neuroscientists screened the genomes of people suffering from a specific brain disease and combed their DNA to uncover a common variant. In this study, Project ENIGMA researchers measured the size of the brain and its memory centers in thousands of MRI images from 21,151 healthy people while simultaneously screening their DNA.

“Earlier studies have uncovered risk genes for common diseases, yet it’s not always understood how these genes affect the brain,” explained Thompson. “This led our team to screen brain scans worldwide for genes that directly harm or protect the brain.”

In poring over the data, Project ENIGMA researchers explored whether any genetic variations correlated to brain size. In particular, the scientists looked for gene variants that deplete brain tissue beyond normal in a healthy person. The sheer scale of the project allowed the team to unearth new genetic variants in people who have bigger brains as well as differences in regions critical to learning and memory.

When the scientists zeroed in on the DNA of people whose images showed smaller brains, they found a consistent relationship between subtle shifts in the genetic code and diminished memory centers. Furthermore, the same genes affected the brain in the same ways in people across diverse populations from Australia, North America and Europe, suggesting new molecular targets for drug development.

“Millions of people carry variations in their DNA that help boost or lower their brains’ susceptibility to a vast range of diseases,” said Thompson. “Once we identify the gene, we can target it with a drug to reduce the risk of disease. People also can take preventive steps through exercise, diet and mental stimulation to erase the effects of a bad gene.”

In an intriguing twist, Project ENIGMA investigators also discovered genes that explain individual differences in intelligence. They found that a variant in a gene called HMGA2 affected brain size as well as a person’s intelligence.

DNA is comprised of four bases: A, C, T and G. People whose HMGA2 gene held a letter “C” instead of “T” on that location of the gene possessed larger brains and scored more highly on standardized IQ tests.

“This is a really exciting discovery: that a single letter change leads to a bigger brain,” said Thompson. “We found fairly unequivocal proof supporting a genetic link to brain function and intelligence. For the first time, we have watertight evidence of how these genes affect the brain. This supplies us with new leads on how to mediate their impact.”

Because disorders like Alzheimer’s, autism and schizophrenia disrupt the brain’s circuitry, Project ENIGMA will next search for genes that influence how the brain is wired. Thompson and his colleagues will use diffusion imaging, a new type of brain scan that maps the communication pathways between cells in the living brain.

Read more at Science Daily

Memory in Adults Impacted by Versions of Four Genes

Two research studies, co-led by UC Davis neurologist Charles DeCarli and conducted by an international team that included more than 80 scientists at 71 institutions in eight countries, has advanced understanding of the genetic components of Alzheimer's disease and of brain development. Both studies appear in the April 15 edition of the journal Nature Genetics.

The first study, based on a genetic analysis of more than 9,000 people, has found that certain versions of four genes may speed shrinkage of a brain region involved in making new memories. The brain area, known as the hippocampus, normally shrinks with age, but if the process speeds up, it could increase vulnerability to Alzheimer's disease, the research suggests.

The second paper identifies two genes associated with intracranial volume -- the space within the skull occupied by the brain when the brain is fully developed in a person's lifespan, usually around age 20.

DeCarli is a pioneer in the field of neuroimaging of the aging brain who has been at the forefront of developing and using quantifiable imaging techniques to define the relationship between structure and function in the healthy aging brain and to characterize the changes associated with vascular and Alzheimer's dementias. He is professor of neurology and director of the UC Davis Alzheimer's Disease Center and the UC Davis Imaging of Dementia and Aging Laboratory.

Genetic variants of hippocampus study

The gene variants identified in the first study do not cause Alzheimer's, but they may rob the hippocampus of a kind of "reserve" against the disease, which is known to cause cell destruction and dramatic shrinkage of this key brain site. The result is severe loss of memory and cognitive ability.

Scientists calculated that hippocampus shrinkage in people with these gene variants accelerates by about four years on average. The risk of Alzheimer's doubles every five years beginning at age 65, so a person of that age would face almost twice the Alzheimer's risk if he or she had these versions of the gene.

Looked at another way, if a person with one of these variants did get Alzheimer's, the disease would attack an already compromised hippocampus and so would lead to a more severe condition at a younger age than otherwise, the research suggests.

"This is definitely a case of 'bigger is better,'" said DeCarli. "We already know that Alzheimer's disease causes much of its damage by shrinking hippocampus volume. If someone loses a greater-than-average amount of volume due to the gene variants we've identified, the hippocampus is more vulnerable to Alzheimer's."

Why the aging hippocampus normally decreases in volume is unclear. The new research shows that the genes most strongly linked to shrinkage are involved in maturation of the hippocampus and in apoptosis, or programmed cell death -- a continual process by which older cells are removed from active duty.

The scientists suggest that if the gene variants they identified do affect either maturation or the rate at which cells die, this could underlie at least some of the increased rates of hippocampus shrinkage.

"Either by making more or healthier hippocampal neurons or preventing them from dying with advancing age, the healthy versions of these genes influence how people remember as they get older," said DeCarli. "The alternate versions of the genes may not fully provide these benefits."

The researchers hope that they can find ways to protect the hippocampus from premature shrinkage or slow its decline by studying the normal regulation of the proteins coded by these genes.

The genetic analysis draws on what is known as a genome-wide association study -- research aimed at finding the common genetic variants associated with specific diseases or other conditions. Different versions of a gene usually come down to changes in just one of the tens of thousands of DNA "letters" that make up genes. These one-letter differences are known as single-nucleotide polymorphisms, or SNPs.

The research involved more than 80 scientists at 71 institutions in 8 countries. Many researchers are needed for such a study in order to put together the large samples, or cohorts, of people whose genetic makeup is to be investigated, to measure the hippocampus from magnetic resonance pictures of the brain and for the labor-intensive statistical analysis of the findings.

The study used a very large assemblage of genetic and disease data called the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium, or CHARGE. The consortium brings together several population-based cohorts in the United States and Europe.

The cohort was made up of 9,232 dementia-free volunteers with an average age of 67. The study identified four different gene variants associated with hippocampus volume decline. One, known as rs7294919, showed a particularly strong link to a reduced hippocampus volume, suggesting that this gene is very important to hippocampus development or health.

The findings were then assessed in two other cohorts. One, including both normal and cognitively compromised people with an average age of 40, showed that three of the suspect SNPs were linked to reduced hippocampus volume. Analysis of results from the third group, comprised primarily of older people, showed a significant association between one of the SNPs and accelerated memory loss.

"With this study, we have new evidence that aging, the hippocampus and memory are influenced by specific genes," DeCarli said. "Understanding how these genes affect the development and aging of the hippocampus may give us new tools to delay memory loss with advanced age and possibly reduce the impact of such diseases as Alzheimer's disease."

Read more at Science Daily