Tag: technology

NASA’s SMAP is ready to get launched

NASA’s SMAP is ready to get launched



Scheduled for launch on Jan. 29, 2015, NASA’s Soil Moisture Active Passive (SMAP) instrument will measure the moisture lodged in Earth’s soils with an unprecedented accuracy and resolution. The instrument’s three main parts are a radar, a radiometer and the largest rotating mesh antenna ever deployed in space.

Remote sensing instruments are called “active” when they emit their own signals and “passive” when they record signals that already exist. The mission’s science instrument ropes together a sensor of each type to corral the highest-resolution, most accurate measurements ever made of soil moisture — a tiny fraction of Earth’s water that has a disproportionately large effect on weather and agriculture.

To enable the mission to meet its accuracy needs while covering the globe every three days or less, SMAP engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, designed and built the largest rotating antenna that could be stowed into a space of only one foot by four feet (30 by 120 centimeters) for launch. The dish is 19.7 feet (6 meters) in diameter.

“We call it the spinning lasso,” said Wendy Edelstein of NASA’s Jet Propulsion Laboratory, Pasadena, California, the SMAP instrument manager. Like the cowboy’s lariat, the antenna is attached on one side to an arm with a crook in its elbow. It spins around the arm at about 14 revolutions per minute (one complete rotation every four seconds). The antenna dish was provided by Northrop Grumman Astro Aerospace in Carpinteria, California. The motor that spins the antenna was provided by the Boeing Company in El Segundo, California.

“The antenna caused us a lot of angst, no doubt about it,” Edelstein noted. Although the antenna must fit during launch into a space not much bigger than a tall kitchen trash can, it must unfold so precisely that the surface shape of the mesh is accurate within about an eighth of an inch (a few millimeters).

The mesh dish is edged with a ring of lightweight graphite supports that stretch apart like a baby gate when a single cable is pulled, drawing the mesh outward. “Making sure we don’t have snags, that the mesh doesn’t hang up on the supports and tear when it’s deploying — all of that requires very careful engineering,” Edelstein said. “We test, and we test, and we test some more. We have a very stable and robust system now.”

SMAP’s radar, developed and built at JPL, uses the antenna to transmit microwaves toward Earth and receive the signals that bounce back, called backscatter. The microwaves penetrate a few inches or more into the soil before they rebound. Changes in the electrical properties of the returning microwaves indicate changes in soil moisture, and also tell whether or not the soil is frozen. Using a complex technique called synthetic aperture radar processing, the radar can produce ultra-sharp images with a resolution of about half a mile to a mile and a half (one to three kilometers).

SMAP’s radiometer detects differences in Earth’s natural emissions of microwaves that are caused by water in soil. To address a problem that has seriously hampered earlier missions using this kind of instrument to study soil moisture, the radiometer designers at NASA’s Goddard Space Flight Center, Greenbelt, Maryland, developed and built one of the most sophisticated signal-processing systems ever created for such a scientific instrument.

The problem is radio frequency interference. The microwave wavelengths that SMAP uses are officially reserved for scientific use, but signals at nearby wavelengths that are used for air traffic control, cell phones and other purposes spill over into SMAP’s wavelengths unpredictably. Conventional signal processing averages data over a long time period, which means that even a short burst of interference skews the record for that whole period. The Goddard engineers devised a new way to delete only the small segments of actual interference, leaving much more of the observations untouched.

Combining the radar and radiometer signals allows scientists to take advantage of the strengths of both technologies while working around their weaknesses. “The radiometer provides more accurate soil moisture but a coarse resolution of about 40 kilometers [25 miles] across,” said JPL’s Eni Njoku, a research scientist with SMAP. “With the radar, you can create very high resolution, but it’s less accurate. To get both an accurate and a high-resolution measurement, we process the two signals together.”

SMAP will be the fifth NASA Earth science mission launched within the last 12 months.

Source : http://www.nasa.gov/smap/

Dinosaur-killer asteroid also nearly wiped out mammals

Dinosaur-killer asteroid also nearly wiped out mammals



The dinosaurs’ extinction 66 million years ago is thought to have opened the way for mammals to dominate the land. But a new study claims many of them died off too.

“If a few lucky species didn’t make it through, then mammals may have gone the way of the dinosaurs and we wouldn’t be here,” said Steve Brusatte of the University of Edinburgh in the U.K., one of the authors of a report on the findings.

Among mammals, the study argues, the brunt of the disaster seems to have hit a group known as metatherians—extinct relatives of living marsupials (“mammals with pouches,” such as opossums and kangaroos.) These thrived in the shadow of the dinosaurs during the Cretaceous period, just before the extinction.

The study, published in the research journal Zookeys, finds these once-abundant mammals nearly followed the dinosaurs into oblivion.

When a 10-km (6-mile)-wide asteroid struck what is now Mexico, unleashing a global cataclysm, some two-thirds of all metatherians living in North America perished, according to the researchers. These casualties, they said, included more than 90 percent of species living in the northern Great Plains, the best area in the world for preserving latest Cretaceous mammal fossils.

Metatherians, the scientists added, would never recover their previous diversity, which is why marsupials are rare today and largely restricted to areas in Australia and South America. Taking advantage of the metatherian demise were the placental mammals: species that give live birth to well-developed young. They are almost everywhere today and include everything from mice to men.

“It wasn’t only that dinosaurs died out, providing an opportunity for mammals to reign, but that many types of mammals, such as most metatherians, died out too—this allowed advanced placental mammals to rise to dominance,” said Thomas Williamson of the New Mexico Museum of Natural History and Science, lead author of the paper.

The study reviews the Cretaceous evolutionary history of metatherians and provides a family tree for these mammals based on the latest fossil records, which researchers said allowed them to study extinction patterns in unprecedented detail.

Source :  www.world-science.net

Curiosity readings point to mysterious, pulsing source of methane on Mars

Curiosity readings point to mysterious, pulsing source of methane on Mars



Levels of the organic gas methane are periodically spiking at the Gale Crater on Mars—suggesting something, possibly something alive, is creating the substance, scientists say.

Most of Earth’s methane production has a biological origin, but there are other ways methane, the simplest organic molecule, can arise naturally. Organic molecules are carbon-based and are essential ingredients for life.

The new findings, from the NASA Mars rover Curiosity, are published this week in the research journal Science.

Investigators said the findings suggest that the methane level in Mars’ atmosphere at the 154-km (96 mile) wide crater is generally lower than models predict, but that it spikes often. This implies the gas arises periodically from some nearby source, they added.

The scientists, from the NASA Jet Propulsion Laboratory in Pasadena, Calif. and other institutions, used 20 months of data collected by instruments on Curiosity to gauge levels of the gas at crater, near where the rover landed.

Their study found that the stable, background level of atmospheric methane is less than half of what was expected from known processes, such as the light-induced breakdown of dust and organic materials delivered to Mars by meteorites.

However, the researchers also found that this background level of methane spiked about tenfold, sometimes over the course of just 60 Martian days, which was surprising because the gas is expected to have a lifetime of about 300 years. The results suggest that methane is occasionally produced or vented near the crater, which is near the Martian equator, they added.

NASA originally chose Gale Crater, which has a mountain in the middle of it, as a landing site for the rover because there were signs of water in the area. The crater is believed to have formed with a meteor hit Mars in its early history, about 3.5 to 3.8 billion years ago.

The announcement comes just weeks after another report concluding that a Martian meteorite called Tissint contains organic molecules of possible biological origin.


source: http://www.world-science.net/

Smoking may kill off the Y chromosome in men’s blood cells

Smoking may kill off the Y chromosome in men’s blood cells



New research suggests the Y chromosome—a repository of genes that only males have—may help explain why men live less long than women, and are more susceptible to smoking-related cancers.

With advancing age, some cells can lose their Y chromosome. Two new studies suggest this loss may increase cancer risk—and that smoking may exacerbate the chromosome loss. Both projects came from the same group of researchers, and while they did not prove cause-and-effect relationships, they found associations between the events in question.

The earlier study, published in the research journal Nature Genetics online April 28, “demonstrated an association between loss of the Y chromosome in blood and greater risk for cancer,” said Lars Forsberg of Uppsala University in Sweden, one of the investigators.

For the second project, published in the Dec. 4 issue of the research journal Science, he added that the group tested “if there were any lifestyle- or clinical factors that could be linked to loss of the Y chromosome.”

The result: “Out of a large number of factors that were studied, such as age, blood pressure, diabetes, alcohol intake and smoking, we found that loss of the Y chromosome in a fraction of the blood cells was more common in smokers than in non-smokers.”

Y chromosome loss is “the most common human mutation” to begin with, added Jan Dumanski, a co-researcher at Uppsala. The new work “may in part explain why men in general have a shorter life span than women, and why smoking is more dangerous for men.”

Smoking is a risk factor for various diseases, not only lung cancer, the researchers noted; male smokers have shown a greater risk of developing non-respiratory-tract cancers than female smokers.

The investigators found the association between smoking and Y chromosome loss to be “dose dependent”—heavy smokers had more widespread losses. But ex-smokers who had quit showed normal levels of Y chromosome loss. So “this process might be reversible,” which “could be very persuasive for motivating smokers to quit,” said Forsberg.

How the smoking-induced Y chromosome loss in blood cells is linked to cancer remains unclear. Perhaps immune cells in blood, bereft of Y chromosomes, are less able to fight cancer cells, the scientists speculated.

Source : www.world-science.net

Brain network that makes humans smarter than chimps found

Brain network that makes humans smarter than chimps found



When it comes to getting out of a tricky situation, we humans have an edge over our evolutionary relatives. Take, for example, the Apollo 13 voyage in which engineers, against all odds, improvised a chemical filter on a lunar module to prevent carbon dioxide buildup from killing the crew.

Scientists say they have found mounting evidence that helps explain how humans have excelled at “relational reasoning,” a skill in which we discern patterns and relationships to make sense of seemingly unrelated information, such as solving problems in unfamiliar circumstances.

Their findings link such reasoning to subtle changes in brain areas known the frontal and parietal lobes, at the top of the head and behind the forehead. Among other things, the scientists say the network of nerve cell connections in this region—the “frontoparietal network”—aids in analysis, memory retrieval, abstract thinking and problem-solving, and has the fluidity to adapt according to the task at hand.

“This research has led us to take seriously the possibility that tweaks to this network over an evolutionary timescale could help to explain differences in the way that humans and other primates solve problems,” said University of California Berkeley neuroscientist Silvia Bunge, the study’s principal investigator.

“It’s not just that we humans have language at our disposal. We also have the capacity to compare and integrate several pieces of information in a way that other primates don’t,” she added.

In reviewing dozens of studies – including their own – that use brain imaging, neuropsychology, developmental cognitive and other methods, the researchers concluded that anatomical changes in the lateral frontoparietal network over millennia have boosted our reasoning.

There is “supporting evidence across species,” added Michael Vendetti, co-author of the study and a postdoctoral researcher in neuroscience at UC Berkeley.

In relational reasoning, we make comparisons and find equivalencies, as one does in algebra, for example. “First-order” comparisons identify several types of relationship between two items or activities: semantic (hammer is used to hit a nail); numeric (four is greater than two); temporal (we get out of bed before we go to work) or visuospatial (the bird is on top of the house). “Second-order” or higher-order comparisons take this a step further by equating two or more sets of first-order relations (a chain is to a link as a bouquet is to a flower).

The researchers identified three brain areas key to relational reasoning, called the rostrolateral prefrontal cortex, the dorsolateral prefrontal cortex and the inferior parietal lobule, with the rostrolateral region more actively engaged in second-order relational reasoning.

Also crucial to their finding was a study led by Oxford University neuroscientist Matthew Rushworth that compared neural patterns in humans and macaque monkeys. While humans, apes and monkeys found to share similarities in the frontal and parietal brain regions, activity in the human rostrolateral prefrontal cortex differed significantly from that of the macaque monkey’s frontal cortex, the study found.

“We had hypothesized that there could have been evolutionary changes to this region to support our reasoning ability, so we were really excited when Rushworth and his colleagues came out with these findings,” Vendetti said.

Meanwhile, in the behavioral studies they analyzed, humans were found to use higher-order strategies to guide their judgment while non-human primates relied more heavily on perceptual similarities and were slower at reasoning and problem-solving.

“These results do not necessarily prove that non-human primates are unable to reason using higher-order thinking, but if it is possible to train non-humans to produce human-like performance on tasks associated with higher-order relational thinking, it is certainly not something that comes naturally to them,” the study concluded. The work is published in the Dec. 3 issue of the journal Neuron.

Source : www.world-science.net

Mars rock shows traces of biological activity

Mars rock shows traces of biological activity



Did Mars ever have life? Might it still? A meteorite identified as coming from Mars has reignited the old debate. A study published this month argues that the rock contains traces of carbon with a likely biological origin, like coal, which comes from remains of long-ago plants.

“So far, there is no other theory that we find more compelling,” said study co-author Philippe Gillet, stressing that he’s open to being proven wrong.

Gillet and colleagues from China, Japan and Germany argue that the carbon could have gotten into the rock through contact with fluid rich in organic material. The study appears in the journal Meteoritic and Planetary Sciences

Thrown off Mars after an asteroid hit its surface, the meteorite, named Tissint, fell on the Moroccan desert on July 18, 2011, in view of several witnesses, the scientists said. Studies found the rock had small fissures filled with organic, carbon-containing matter.

The researchers carried out several analyses to conclude that the rock didn’t originate on Earth and that the carbon got into it before it left Mars. They took issue with a previous proposal that the carbon traces originated through the high-temperature crystallization of magma, or molten rock. Gillet and colleagues argue that more probably, liquids containing organic compounds of biological origin infiltrated Tissint’s “mother” rock at low temperatures, near the Martian surface.

These conclusions are supported by several properties of the meteorite’s carbon, such as its levels of so-called carbon-13 compared to carbon-12, they explained. This was found to be significantly lower than the ratio of carbon-13 in the carbon dioxide of Mars’s atmosphere, previously measured by the Phoenix and Curiosity rovers. Moreover, this difference corresponds perfectly with what is seen on Earth between a piece of coal and the carbon in the atmosphere, the scientists argue.

The researchers say the organic matter could also have reached Mars when very primitive meteorites, called carbonated chondrites, fell there, but probably not, because such meteorites contain very low levels of organic matter.

“Insisting on certainty is unwise, particularly on such a sensitive topic,” said Gillet, who directs the Earth and Planetary Sciences Laboratory at the École Polytechnique Fédérale de Lausanne, a Swiss institute of technology. “I’m completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars – at least in the past.”

Parasites found to use “Trojan horses” to quell resistance

Parasites found to use “Trojan horses” to quell resistance



Parasites use a “Trojan horse”-like trick to suppress the immunity of their victims, according to a study whose authors hope it will pave the way for new treatments.

The researchers found that parasites can dump tiny sealed packages of genetic material into their victims’ cells that serve to head off retaliation by the victim’s immune system. The packages, known as vesicles, mimic packages that are produced naturally in most organisms for everyday functions such as carrying nutrients and chemical messages among cells.

The parasite uses vesicles to hide its material inside a seemingly friendly exterior, like the giant horse statue that the ancient Greeks reputedly left as a gift to the city of Troy. This was a trick to sneak Greek soldiers—the statue was full of them—into the enemy city.

The study, carried out on a parasite of mice, showed that the material in the packages can interact with the mouse’s own genes. It manipulates the cell’s machinery to keep it from producing immunity-related molecules.

“We can see for the first time that parasites can use packages to sneak their material into the cells of other organisms,” said Amy Buck of the University of Edinburgh in the U.K., who led the study. “We now can develop ways to target this with implications for the billions of people and animals at risk of infectious diseases and allergy.”

The researchers say the finding could inform new strategies for treating diseases caused by parasitic worms, which affect hundreds of millions of people and animals. The findings also offer a possible way to treat allergies, such as hay fever, because the immune mechanism that parasites block is also linked to allergic reactions.

The genetic material from the parasites can also be detected in human blood, suggesting that this could be used as a test to detect infection in people, the researchers said. Ongoing studies are looking into whether other parasites and viruses use this same strategy. The study is published in the journal Nature Communications.

Scientists found : Vultures evolved an extreme gut to cope with disgusting dietary habits

Scientists found : Vultures evolved an extreme gut to cope with disgusting dietary habits



Some extreme adaptations—including very strong stomach acid—help vultures live on rotting, often poop-contaminated meat that would poison or kill most other animals, a study has found.

When vultures eat lunch they happily strip rotting carcasses to the bone. If a hide is too tough to bite through, they don’t hesitate to enter a carcass using other routes, including the back entrance—the anus. What ingredient this adds to the feast is not hard to see.

Yet the birds are apparently immune to the resulting cocktail of deadly microbes in their dinner such as Clostridia, Fuso- and Anthrax-bacteria.

“To investigate vultures’ ability to survive eating this putrid cocktail, we generated DNA profiles from the community of bacteria living on the face and gut of 50 vultures from the U.S.A.,” said researcher Lars Hestbjerg Hansen of Aarhus University in Denmark.

“Our findings enable us to reconstruct both the similarities, and differences, between the bacteria found in turkey vultures and black vultures, distributed widely in the Western Hemisphere.”

On average, the researchers found vultures’ facial skin contained DNA from 528 different types of microorganisms, but the gut revealed DNA from only 76 types. A lot of them are getting killed on the way down, said Roggenbuck and colleagues, whose findings are published in the journal Nature Communications.

“There has been strong adaptation in vultures when it comes to dealing with the toxic bacteria they digest. On one hand vultures have developed an extremely tough digestive system, which simply acts to destroy the majority of the dangerous bacteria they ingest,” he explained.

“On the other hand, vultures also appear to have developed a tolerance towards some of the deadly bacteria—species that would kill other animals actively seem to flourish in the vulture lower intestine.”

These observations, the researchers said, raise the question of whether the Clostridia and Fusobacteria in the gut simply outcompete the other bacteria without benefitting the bird, or in contrast, if their presence actually confers dietary advantages for the vultures. The results, they say, suggest it’s probably a bit of both—the surviving bacteria probably outcompete the other microbes, but also provide the birds with important nutrients by helping to break down the carrion.

The universe of microbes within the avian gut is not well understood but “it is not unreasonable to suppose that the relationship between birds and their microbes has been as important in avian evolution as the development of powered flight and song,” said Gary Graves of the Smithsonian Institution’s National Museum of Natural History in Washington, who participated in the work.

source : www.world-science.net

Largest known landslide occurred 21 million years ago

Largest known landslide occurred 21 million years ago



An enormous landslide more than 21 million years ago in what is now Utah could be the largest known in all of Earth’s land areas, geologists are reporting.

The so-called Markagunt gravity slide covered an area greater than the state of Rhode Island within minutes—moving fast enough to melt rock into glass due to the immense friction, the researchers said. Any animals in the way would have been quickly mowed down.

Geologists previously knew about parts of the landslide, but in new work, geologist David Hacker of Kent State University in Ohio hiked through wilderness to find features indicating the slide was much bigger than previously realized. The findings are published in the November issue of the journal Geology.

The landslide took place in an area between what is now Bryce Canyon National Park and the town of Beaver, Utah, Hacker and colleagues said, and covered about 1,300 square miles (3,400 square km). That would make it one of the two largest known continental landslides (larger slides exist on the ocean floors).

Its rival in size, the “Heart Mountain slide,” which took place around 50 million years ago in northwest Wyoming, was discovered in the 1940s. The Markagunt slide could prove to be much larger, once it is better mapped, Hacker and colleagues said.

They suggest it occurred when not just one mountainside gave way, but a whole portion of a volcanic mountain range whose base had been pushed up higher and higher by molten rock, or magma, gathering beneath.

“Large-scale catastrophic collapses of volcanic fields such as these are rare but represent the largest known landslides on the surface of the Earth,” the authors wrote. The landslide was over 55 miles (90 km) long, Hacker added, though today, “looking at it, you wouldn’t even recognize it as a landslide.”

Understanding the mega-landslide could help geologists better understand these extreme events, he said. The Markagunt and the Heart Mountain slides document for the first time how large portions of ancient volcanic fields have collapsed, Hacker explained, representing “a new class of hazards in volcanic fields.”

Such events could theoretically happen in modern volcanic fields, or groups of volcanic mountains, such as the Cascade Mountains, which include Mt. St. Helens in Washington, he added. But many conditions must come together to produce a landslide. “We study events from the geologic past to better understand what could happen in the future,” said Hacker, who plans to continue mapping and analyzing the slide.

source: world-science.net

Spooky alignment of quasars across billions of light-years

Spooky alignment of quasars across billions of light-years



New observations suggest that galaxies align with each other across vast reaches of space—in a manner that astronomers had expected, but more so, a report said.

The work indicates that over distances of billions of light-years, certain types of super-bright galaxies tend to spin along the same axis. A light-year is the distance light travels in a year.

Astronomers attribute the alignments to characteristics of the large-scale “cosmic web,” in which galaxies overall tend to group themselves into a structure that resembles a kind of web stretching out in all directions.

A closer look at this web reveals countless galaxies arranged along structures that can be described as filaments, sheets and clumps.

The direction of the galaxy’s spin axis, according to the new findings, often follows a filament that the galaxy inhabits.

Previous studies had detected similar sorts of alignments for normal galaxies, but on smaller scales, and less straightforward sorts of alignments. Astronomers attribute the alignments to the ways that galaxies build themselves in the first place by accumulating smaller objects.

In the new study, researchers using the European Southern Observatory’s Very Large Telescope in Chile studied quasars, galaxies with extremely bright centers due to the presence of black holes voraciously gobbling up nearby objects.

A black hole is an object so compact that its gravity sucks in anything that strays too close, including light. Many galaxies are believed to contain a giant black hole at the center. A black hole itself is invisible, but its feeding activities create violent distortions of nearby material that cause it to heat up and give off light. Quasars can shine more brightly than all the stars in the rest of their host galaxies put together.

Quasars are surrounded with spinning discs of extremely hot material, some of which often spouts away in long jets along their axes of rotation.

A team led by Damien Hutsemékers from the University of Liège in Belgium used an instrument on the telescope called FORS to study 93 quasars that were known to form huge groupings spread over billions of light-years. The galaxies are so far away that they are seen as they existed when the Universe was about one third of its current age. That’s because light takes time to get here.

“The first odd thing we noticed was that some of the quasars’ rotation axes were aligned with each other—despite the fact that these quasars are separated by billions of light-years,” said Hutsemékers.

The findings also suggest that the quasar spins tend to follow the large-scale structures they inhabit. So, if the quasars are in a long filament then the spins of the central black holes will point along the filament. The researchers estimate that the probability that these alignments are simply the result of chance is less than 1 percent.

Computer simulations of the universe had revealed similar alignments, but on smaller scales, said study collaborator Dominique Sluse of the Argelander Institute for Astronomy in Bonn, Germany and University of Liège. The discrepancy “may be a hint that there is a missing ingredient in our current models of the cosmos,” he added.

The team couldn’t see the spin axes or the jets of the quasars directly. Instead they measured the “polarization” of each quasar’s light. Light is “polarized” when its waves oscillate in the same direction. For 19 quasars, the researchers found significant polarization. They used this along with other information to deduce the angle of the disc of material falling into the black hole, and in turn the spin axis of the quasar itself.

Why the alignments at all? Most objects in space, including galaxies, tend to spin because they form by accumulating, through gravity, smaller objects. These are usually moving with respect to each other. These motions affect the final, merged object by making it spin, and it won’t stop unless something specifically stops it.

Astronomers believe that the galactic alignments occur because of the ways filaments formed in the first place: they obtained their material presumably because it flowed toward them, not away from them or along them. Some consistency in the direction of this flow could be expected to lead to a corresponding consistency in the spins of the various galaxies.

The spin axis will tend to be at right angles to the direction that material is flowing toward a galaxy as it builds itself, according to writings by Elmo Tempel of the Tartu Observatory in Toravere, Estonia, and Noam Libeskind of the Leibniz Institute for Astrophysics in Potsdam, Germany, who have conducted earlier studies on galactic alignment.

The new study was published on Nov. 19 in the journal Astronomy and Astrophysics.