Jul 23, 2016

Neural networks: Why larger brains are more susceptible to mental illnesses

Macaque brain showing the inter-areal network. Nodes roughly correspond to actual areas, thickness of lines proportional to the logarithm of the numbers of axons.
In humans and other mammals, the cerebral cortex is responsible for sensory, motor, and cognitive functions. Understanding the organization of the neuronal networks in the cortex should provide insights into the computations that they carry out. A study publishing on July 21st in open access journal PLOS Biology shows that the global architecture of the cortical networks in primates (with large brains) and rodents (with small brains) is organized by common principles. Despite the overall network invariances, primate brains have much weaker long-distance connections, which could explain why large brains are more susceptible to certain mental illnesses such as schizophrenia and Alzheimer disease.

In earlier work, Zoltán Toroczkai, from the University of Notre-Dame, USA, Mária Ercsey-Ravasz, from Babes-Bolyai University, Romania and Henry Kennedy, from the University Lyon, France, and colleagues combined tracing studies in macaques, which visualize connections in the brain, with network theory to show that the cortical network structure in this primate is governed by the so-called exponential distance rule (EDR).

The EDR describes a consistent relationship between distances and connection strength. Consistent with the tracing results, the EDR predicts that there are many fewer long-range axons (nerve fibers that function as transmission lines of the nervous system) than short ones, and this can be quantified by a mathematical equation. At the level of cortical areas (such as visual cortex or auditory cortex) examined by the tracing studies, this means the closer two areas are to each other, the more connections exist between them.

In this study, the researchers compare the features of the cortical networks in the macaque -- a mammal with a large cortex -- with those in the mouse, with its much smaller cortex. They used detailed tracing data to quantify connections between functional areas, and those formed the basis for the analysis. Despite the substantial differences in the cortex size between the species and other apparent differences in cortex organization, they found that the fundamental statistical features of all networks followed the EDR.

Based on these results, the researchers hypothesize that the EDR describes an effective design principle that remains constant during the evolution of mammalian brains of different sizes. They present mathematical arguments that support the universal applicability of the EDR as a governing principle of cortical connectivity, as well as further experimental support from high-resolution tracer experiments in small brain areas from macaque, mouse, and mouse lemur (a primate with a very small brain).

Their results, the researchers conclude, "suggest that the EDR plays a key role across the mammalian order to optimize the layout of the inter-areal cortical network allowing larger-brained animals to maintain communication efficiencies combined with increased neuron numbers."

Read more at Science Daily

How rope was made 40,000 years ago

Rope making tool from mammoth ivory from Hohle Fels Cave in southwestern Germany, ca. 40,000 years old.
Prof. Nicholas Conard and members of his team, present the discovery of a tool used to make rope in today‘s edition of the journal: Archäologische Ausgrabungen Baden-Württemberg.

Rope and twine are critical components in the technology of mobile hunters and gatherers. In exceptional cases impressions of string have been found in fired clay and on rare occasions string was depicted in the contexts of Ice Age art, but on the whole almost nothing is known about string, rope and textiles form the Paleolithic.

A key discovery by Conard’s team in Hohle Fels Cave in southwestern Germany and experimental research and testing by Dr. Veerle Rots and her team form the University of Liège is rewriting the history of rope.

The find is a carefully carved and beautifully preserved piece of mammoth ivory 20.4 cm in length with four holes between 7 and 9 mm in diameter. Each of the holes is lined with deep, and precisely cut spiral incisions. The new find demonstrates that these elaborate carvings are technological features of rope-making equipment rather than just decoration.

Similar finds in the past have usually been interpreted as shaft-straighteners, decorated artworks or even musical instruments. Thanks to the exceptional preservation of the find and rigorous testing by the team in Liège, the researchers have demonstrated that the tool was used for making rope out of plant fibers available near Hohle Fels. “This tool answers the question of how rope was made in the Paleolithic”, says Veerle Rots, “a question that has puzzled scientists for decades.”

Excavators found the rope-making tool in archaeological horizon Va near the base of the Aurignacian deposits of the site. Like the famous female figurines and the flutes recovered from the Hohle Fels, the rope-making tool dates to about 40,000 years ago, the time when modern humans arrived in Europe. The discovery underlines the importance of fiber technology and the importance of rope and string for mobile hunters and gatherers trying to cope with challenges of life in the Ice Age.

Prof. Conard’s team has excavated at Hohle Fels over each of the last 20 years, and it is this long-term commitment that has over and over again paid off, to make Hohle Fels one of the best known Paleolithic sites worldwide. Hohle Fels and neighboring sites from the Ach and Lone Valleys have been nominated for UNESCO World Cultural Heritage status. The excavations at Hohle Fels near Schelklingen in the Ach Valley are funded by the HeidelbergCement AG, the Ministry of Science of Baden-Württemberg and the Heidelberger Academie of Sciences.

Read more at Science Daily

Jul 22, 2016

A new key to understanding molecular evolution in space

Ortho-hydrogen converts to para-hydrogen by releasing energy to the ice surface. The conversion rate differed depending on the ice temperature.
Scientists at Hokkaido University have revealed temperature-dependent energy-state conversion of molecular hydrogen on ice surfaces, suggesting the need for a reconsideration of molecular evolution theory.

Molecular hydrogen, the most abundant element in space, is created when two hydrogen atoms bond on minute floating ice particles. It has two energy states: ortho and para, depending on the direction of proton spins. Ortho-hydrogen converts to para-hydrogen on extremely low temperature ice particles, though its mechanism remained unclear.

When molecular hydrogen is released from tiny ice particles in space, the particular state of its energy plays a key role in molecular evolution -- the process of generating a wide range of molecules over a long period of time in space.

In the study, the researchers developed a special system that could detect the ortho/para ratio of molecular hydrogen on artificial ice particles. The study discovered that the ratio of the ortho-to-para conversion rate (as time passed) was dramatically different in the relatively small temperature range of between -264C and -257C, thus, in a world first, unraveling the conversion mechanism. Ortho-hydrogen converts to para-hydrogen by releasing energy to the ice, in a temperature dependent manner.

Until now, the energy conversion rate was believed to be identical regardless of the temperature of ice particles -- a theory that has been scotched by the new research. The finding will likely prompt scientists to rebuild theories of molecular evolution, opening new horizons in studies of molecular formation and molecular evolution.

From Science Daily

Neanderthals in Germany: First population peak, then sudden extinction

Neanderthal depiction (stock image). Neanderthals lived in the Middle Paleolithic, the middle period of the Old Stone Age. This period encompasses the time from roughly 200,000 to 40,000 before our times.
Neanderthals once populated the entire European continent. Around 45,000 years ago, Homo neanderthalensis was the predominant human species in Europe. Archaeological findings show that there were also several settlements in Germany. However, the era of the Neanderthal came to an end quite suddenly.

Based on an analysis of the known archaeological sites, Professor Jürgen Richter from Collaborative Research Center 806 -- Our Way to Europe, in which the universities of Cologne, Bonn and Aachen cooperate, comes to the conclusion that Neanderthals reached their population peak right before their population rapidly declined and they eventually became extinct.

Neanderthals lived in the Middle Paleolithic, the middle period of the Old Stone Age. This period encompasses the time from roughly 200,000 to 40,000 before our times. In his article published in the Quaternary International Journal, Richter comes to the conclusion that more than 50 percent of the known Neanderthal settlement sites in Germany can be dated to the Middle Paleolithic. More precisely, they date back 60,000 to 43,000 years before our times. Thus, the Neanderthal population peak seems to lie in this period.

The number of sites, their analysis and the analysis of the artefacts found at these settlements indicate that the Neanderthal population in Germany was subject to extreme demographic fluctuations. During the Middle Paleolithic, there appear to have been several migrations, population increase and decline, extinction in certain areas and then a return of settlers to these areas.

While for the time period between 110,000 to 70,000 years ago there are only four known settlement sites, in the following period from 70,000 to 43,000 years ago there are ninety-four. In less than 1,000 years after this demographic peak, however, there was a rapid decline and the Neanderthal disappeared from the scene. Precisely why the species died out is still unclear. Perhaps it was due to low genetic diversity, perhaps to the rise of Homo sapiens. This question will continue to occupy scientists.

From Science Daily

Human Gut Bacteria Took Root Before We Were Human

The relationship between humans and the bacteria in our guts extends far back into the past — to the time before modern humans even existed, a new study finds.

Microbes in two bacterial families — Bacteroidaceae and Bifidobacteriaceae, which are present in humans and African apes — likely colonized the guts of a shared ancestor of both groups around 15 million years ago, the researchers discovered.

Since then, the bacteria have inhabited the digestive systems of humans and apes for thousands of generations.

The researchers' genetic data also tell a story of parallel evolution — in the microbes, and in the primate hosts they inhabited.

"Just like we share a common ancestor with chimpanzees about 6 million years ago, a lot of our gut bacteria share a common ancestor with chimpanzee gut bacteria, which diverged around the same time," said study co-author Andrew Moeller, a postdoctoral researcher at the University of California at Berkeley.

"And the same is true for human and gorilla gut bacteria. We share a common ancestor maybe about 15 million years ago, and we found that some of our gut bacteria shared common ancestry about the same time," Moeller said in a statement.

Recent research has shown that humans' complex communities of gut microbes may influence our immune systems, and may be associated with certain moods and behaviors.

This new study provides the first evidence of when in our evolutionary history those microbes may have colonized us, the researchers said.

Previous findings enabled the researchers to identify an animal species purely from the groups of microbes in their gut, study co-author Howard Ochman, a professor of integrative biology at the University of Texas at Austin, said in a statement.

Read more at Discovery News

Farming Began in Two Separate Places in the Mideast

The Fertile Crescent and the Middle East, seen from space.
The reason that you're able to sit in a comfortable chair in your home and read this article on your tablet or laptop is that many thousands of years ago, humans shifted from being nomadic hunter-gatherers to raising their own food crops and domesticating animals. That breakthrough enabled our species to stay in one place long enough to build villages, towns and cities, and to start developing the technologies that eventually led to the advanced civilization we have today.

But who actually was the first to invent farming? A new genetic study suggests that two different groups of people in the Middle East independently developed agriculture, and then gradually spread their practices to Europe, Africa and Asia.

In the study, which recently was published online at Biorxiv.org, researchers looked at the genomes of 44 individuals who lived between 3,500 and 14,000 years ago in present-day Armenia, Turkey, Israel, Jordan and Iran. The difficult-to-obtain ancient DNA was extracted from a tiny ear bone -- called the petrous -- by a team led by Losif Lazaridis and David Reich, two population geneticists at Harvard Medical school.

The team found stark differences between the genomes of ancient people on the southern side of the region in Israel and Jordan, and those on the other side of the Zagros mountains in western Iran. That pattern is consistent with existing evidence that the two groups didn't mingle, and separately developed the ability to grow crops.

"There has been a school of thought arguing that everything happens first in the southern Levant and everyone learns how to be farmers from this initial dispersal," Roger Matthews, an archaeologist at the University of Reading, U.K., who co-directs the Central Zagros Archaeological Project in Iran, explained in a Nature.com article. "But the archaeological evidence shows very strong local traditions that are clearly not in communication with each other, persisting for centuries if not millennia."

Agriculture seems to have developed about 11,000 years ago in those places. The two groups also focused on different agricultural products, with the southern farmers domesticating goats and growing cereals such as emmer, while the western group cultivated barley and wheat.

About 9,500 years ago, the two populations of farmers finally may have mixed in eastern Turkey, where they probably were searching for sources of obsidian, which they needed to make tools. By the time farmers from Turkey began migrating to Europe, they had what the researchers call a "Neolithic Toolkit," which included crops, animals and tools from both farming traditions.

From Discovery News

Beyond Star Trek: Hubble Probes the Final Frontier

The Hubble Space Telescope continues to use massive galactic clusters to create natural cosmic lenses to superboost its observing powers.

Just as "Star Trek Beyond" hits theaters, Hubble has released its own view of the final frontier.

Located some four billion light-years away, the Abell S1063 galaxy cluster creates a dazzling scene. The sheer mass of the cluster has corralled light from galaxies that exist way beyond Hubble's observing capabilities, creating those strange-looking arcs and warped galactic shapes.

The light from these far-away galaxies travels through the cluster, but as the space-time surrounding the cluster is warped by its mass, the light is deflected -- a bit like how the path of light is refracted through a magnifying lens. And it has the same effect; distant objects are magnified by these cosmic lenses, boosting Hubble's already impressive magnification. This is known as gravitational lensing and it is a direct prediction from Einstein's theory of general relativity.

The coolest thing is that Abell S1063 contains images of 16 background galaxies and one of those primordial galaxies existed only a billion years after the Big Bang. This ancient specimen comes from the first generation of galaxies to appear in the universe, so its light has taken nearly 13 billion years to travel from that galaxy, through the space-time magnification in the Abell S1063 cluster and into Hubble's lens.

Though seeing galaxies from the dawn of the universe is a scientific goldmine in itself, measurements of their distorted shapes can help astronomers map the distribution of dark matter within the cluster, helping us further refine our theories on what this mysterious mass could be.

Abell S1063, a galaxy cluster, was observed by the NASA/ESA Hubble Space Telescope as part of the Frontier Fields program. The huge mass of the cluster acts as a cosmic magnifying glass and enlarges even more distant galaxies.
This most recent observation is a part of Hubble's Frontier Fields program that really pushes the envelope for the veteran telescope. By combining Hubble's unobstructed view of the visible universe and using this quirk of general relativity, we are learning so much more about the early universe, spying some galaxies that existed only a few hundred million years after the birth of the universe and providing compelling new clues as to the nature of some of the biggest mysteries beyond our current cosmological understanding.

Read more at Discovery News

Jul 21, 2016

Genome of 6,000-year-old barley grains sequenced for first time

Right: Photograph during excavation exhibiting excellent dry preservation of plant remains. Left: A well-preserved, desiccated barley grain found at Yoram Cave
An international team of researchers has succeeded for the first time in sequencing the genome of Chalcolithic barley grains. This is the oldest plant genome to be reconstructed to date. The 6,000-year-old seeds were retrieved from Yoram Cave in the southern cliff of Masada fortress in the Judean Desert in Israel, close to the Dead Sea. Genetically, the prehistoric barley is very similar to present-day barley grown in the Southern Levant, supporting the existing hypothesis of barley domestication having occurred in the Upper Jordan Valley.

Members of the research team are from the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) in Gatersleben, Germany; Bar-Ilan University in Ramat Gan, Israel; Hebrew University, Jerusalem, Israel; the Max Planck Institute for the Science of Human History in Jena, Germany; and the University of Haifa, Israel; The James Hutton Institute, UK; University of California, Santa Cruz, USA; University of Minnesota St. Paul, USA; University of Tübingen, Germany.

The analyzed grains, together with tens of thousands of other plant remains, were retrieved during a systematic archaeological excavation headed by Uri Davidovich, from the Institute of Archaeology, The Hebrew University of Jerusalem, and Nimrod Marom, from Zinman Institute of Archaeology, University of Haifa, Israel. The archaeobotanical analysis was led by Ehud Weiss, of Bar-Ilan University. The cave is very difficult to access and was used only for a short time by humans, some 6,000 years ago, probably as ephemeral refuge.

Oldest plant genome reconstructed to date

Most examination of archaeobotanical findings has been limited to the comparison of ancient and present-day specimens based on their morphology. Up to now, only prehistoric corn has been genetically reconstructed. In this research, the team succeeded in sequencing the complete genome of the 6,000-year-old barley grains. The results are now published in the online version of the journal Nature Genetics.

"These archaeological remains provided a unique opportunity for us to finally sequence a Chalcolithic plant genome. The genetic material has been well-preserved for several millennia due to the extreme dryness of the region," explains Ehud Weiss, of Bar-Ilan University. In order to determine the age of the ancient seeds, the researchers split the grains and subjected half of them to radiocarbon dating while the other half was used to extract the ancient DNA. "For us, ancient DNA works like a time capsule that allows us to travel back in history and look into the domestication of crop plants at distinct time points in the past," explains Johannes Krause, Director of the Department of Archaeogenetics at the Max Planck Institute for the Science of Human History in Jena. The genome of Chalcolithic barley grains is the oldest plant genome to be reconstructed to date.

Domestication of barley completed very early

Wheat and barley were already grown 10,000 years ago in the Fertile Crescent, a sickle-shaped region stretching from present-day Iraq and Iran through Turkey and Syria into Lebanon, Jordan and Israel. Up to this day, the wild forms of these two crops persist in the region and are among the major model species studied at the Institute of Evolution in the University of Haifa. "It was from there that grain farming originated and later spread to Europe, Asia and North Africa," explains Tzion Fahima, of the University of Haifa.

"Our analyses show that the seeds cultivated 6,000 years ago greatly differ genetically from the wild forms we find today in the region. However, they show considerable genetic overlap with present-day domesticated lines from the region," explains Nils Stein, who directed the comparison of the ancient genome with modern genomes at the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, with the support of Robbie Waugh and colleagues at the James Hutton Institute, Dundee, Scotland, and Gary Muehlbauer, University of Minnesota, USA. "This demonstrates that the domestication of barley in the Fertile Crescent was already well advanced very early."

The comparison of the ancient seeds with wild forms from the region and with so-called 'landraces' (i.e., local barley lines grown by farmers in the Near East) enabled to geographically suggest, according to Tzion Fahima and his colleagues at the University of Haifa and Israel's Tel-Hai College, "the origin of the domestication of barley within the Upper Jordan Valley -- a hypothesis that is also supported by two archaeological sites in the surrounding area where the hitherto earliest remains of barley cultivation have been found.

Immigrants "trust" in extant landraces

Also the genetic overlap with present-day domesticated lines from the region is revealing to the researchers. "This similarity is an amazing finding considering to what extent the climate, but also the local flora and fauna, as well as the agricultural methods, have changed over this long period of time," says Martin Mascher, from the Leibniz Institute of Plant Genetics and Crop Plant Research, the lead author of the study. The researchers therefore assume that conquerors and immigrants coming to the region did not bring their own crop seeds from their former homelands, but continued cultivating the locally adapted extant landraces.

Read more at Science Daily

Super-eruptions may give a year's warning before they blow

One of the 73 quartz crystals used in the study. They averaged about one millimeter in diameter.
Super-eruptions -- volcanic events large enough to devastate the entire planet -- give only about a year's warning before they blow.

That is the conclusion of a new microscopic analysis of quartz crystals in pumice taken from the Bishop Tuff in eastern California, which is the site of the super-eruption that formed the Long Valley Caldera 760,000 years ago.

The study is described in the paper "The year leading to a supereruption" by Guilherme Gualda, associate professor of earth and environment sciences at Vanderbilt University, and Stephen Sutton at the University of Chicago published July 20 in the journal PLOS One.

"The evolution of a giant, super-eruption-feeding magma body is characterized by events taking place at a variety of time scales," said Gualda. Tens of thousands of years are needed to prime the crust to generate sufficient eruptible magma. Once established, these melt-rich, giant magma bodies are unstable features that last for only centuries to few millennia. "Now we have shown that the onset of the process of decompression, which releases the gas bubbles that power the eruption, starts less than a year before eruption."

Gualda and Sutton analyzed dozens of small quartz crystals from the Bishop Tuff. Previous investigations of quartz crystals from several super-eruptions, including Long Valley, have noted that they have distinctive surface rims. These studies concluded that the rims formed in less than a century before eruption.

The new study uses a more accurate method for measuring rim growth times pinned on variations in the concentration of titanium in the crystal. Titanium is one of the few impurities that is incorporated into quartz in appreciable amounts and it diffuses fast enough to permit probing of time scales as short as minutes. However, it is extremely difficult to measure the small levels of titanium involved at sufficient spatial resolution. So the researchers established that the concentration of titanium in quartz directly correlates with the amount of light produced when a material is bombarded by electrons, an effect called cathodoluminescence. This allowed them to use cathodoluminescence images to make high-resolution measurements of variations in titanium concentration and, based on this, to determine rim growth times and growth rates.

"Maximum rim growth times span from approximately 1 minute to 35 years, with a median of approximately 4 days. More than 70 percent of rim growth times are less than 1 year, showing that quartz rims have mostly grown in the days to months prior to eruption... . Growth took place under conditions of high supersaturation suggesting that rim growth marks the onset of decompression and the transition from pre-eruptive to syn-eruptive conditions," the paper summarized.

According to Gualda, the decompression period would likely be accompanied by the expansion of the magma body which should have detectable effects on the Earth's surface. While more work is needed to understand what exactly the signs at the surface would be, the study suggests that signs of an impending super-eruption would start to be felt within a year of eruption, and they would intensify as the eruption neared.

Very large eruptions -- including super-eruptions -- have taken place in a number of places worldwide in the recent geological past. The Taupo Volcanic Zone in New Zealand was the site of the most recent super-eruption -- the Oruanui eruption at 26,500 years -- and it includes deposits from more than a dozen very large eruptions that took place in the last couple of million years. Campi Flegrei in Italy produced a very large eruption 40,000 years ago. Indonesia was the site of the Toba super-eruption in Sumatra 75,000 years ago and the Tambora eruption in 1815. In the United States, Yellowstone has experienced three super-eruptions over the last two million years. In light of this evidence, it seems inevitable that another super-eruption will strike the Earth in the future.

Read more at Science Daily

Hunter-Gatherer Tribes: The Original Social Networks

In an era before smartphones or social media or even permanent shelter, a social network branched no further than the members within a hunter-gatherer group.

In some pockets of the planet, that way of life still exists today. While modern social networks, particularly those that flourish on Facebook and Twitter, thrive on attention, these ancient relationships instead traded on a slightly more important commodity: food.

Based on an analysis by researchers publishing their work in the journal Current Biology, social hierarchies in hunter-gatherer tribes are closely related to food sharing.

 For the study, anthropologists at the University College London observed for several months two groups of hunter-gatherers, the Palanan Agta in the Philippines and the Mbendjele BaYaka in the Republic of Congo.

The U.K. team found that both populations shared multi-layered social structures with relationships and hierarchies forged by food sharing and reciprocity. An individual first shares food with immediate family, then three or four closely related households, then the wider camp, which can vary in size, the authors wrote.

No word yet on what the equivalent of a "Like" button would be in hunter-gatherer societies.

"Despite their geographical separation and different foraging niches, communities of Agta and Mbendjele hunter-gatherers are structured in similar ways," the authors wrote.

"We suggest that this multilevel social organization allows individuals access to the range of social relationships required to mitigate against day-to-day variability in foraging success inherent in the human foraging economy," they said.

 Last week, the same University of College London team published another study in the journal Open Science in which they concluded that the most stable hunter-gatherer camps are those in which food sharing is more common. In less-successful camps, individuals don't divide, but instead take food and other resources from others, a situation described by the researchers as "demand sharing."

Outside of humans, cooperation among unrelated individuals within a group is rare. "No other apes share food to the extent that humans do," said Andrea Migliano, co-author of both studies.

"Sharing is a crucial adaptation to hunter-gatherers' lifestyles, central to their resilience and central to the evolution of mankind," she added.

Read more at Discovery News

No WIMPs Here: Dark Matter Search Draws a Blank

The Large Underground Xenon (LUX) dark matter detector is seen here after it was installed at the center of a water tank later filled with more than 70,000 gallons of ultra-pure deionized water, part of an experiment to look for dark matter particles.
Scientists on Thursday said they were finished with a 20-month search for WIMPS, or weakly interacting massive particles, which took place inside an abandoned gold mine a mile beneath solid rock in the Black Hills of South Dakota.

Their WIMP detector consisted of a tank of cooled liquid xenon that was surrounded by sensors to measure tiny flashes of light caused by dark matter particles colliding with xenon atoms.

To shield against cosmic rays, the tank of xenon was inside a 72,000-gallon tank of ultra-pure water.

Scientists modeled what a WIMP crashing into a xenon atom would look like and honed their hunting skills by blasting neutrons and radioactive gases into the detector.

Though the Large Underground Xenon, or LUX, experiment was four times more sensitive than original expectations, it was unable to detect any dark matter particles, scientists said Thursday at a conference in Sheffield, United Kingdom.

While the experiment eliminates some WIMP candidates, it opens the door to other particle models that will need a larger and more sensitive experiment to detect, said Brown University physicist Richard Gaitskell.

A dark matter particle remains the leading theory to explain the universe's so-called "missing mass." Roughly 80 percent of the universe's mass cannot be directly detected. Its existence is inferred by measuring its gravitational impacts on the motions of galaxies and on the bending of light passing by.

For now, the hunt for WIMPS moves to the Large Hadron Collider (LHC) at CERN in Geneva, the world's most-powerful atom smasher.

"LHC is looking to observe new particles that would provide the first evidence of a new theory that goes beyond the existing Standard Model. It is likely that if they see new particles, the associated physics will also provide an explanation for how dark matter particles were produced in the early universe," Gaitskell wrote in an email to DNews.

"At present, LHC has not seen any clear evidence for such new physics. We are waiting to see their next new analyses in the coming weeks," he added.

Evidence of for dark matter also could come from the Alpha Magnetic Spectrometer, or AMS, a particle detector attached to the International Space Station.

Read more at Discovery News

Jul 20, 2016

Thinking inside the box: How our brain puts the world in order

Neuroscientists have found the sorting center in the brain.
The world around is complex and changing constantly. To put it in order, we devise categories into which we sort new concepts. To do this we apply different strategies. A team of researchers at the Ruhr University Bochum (RUB) led by Prof. Dr. Boris Suchan, department of neuropsychology, and Prof. Dr. Onur Güntürkün, department of biopsychology, wanted to find our which areas of the brain regulate these strategies.

The results of their study using magnetic resonance imaging (MRI) show that there are indeed particular brain areas, which become active when a certain strategy of categorisation is applied.

When we categorise objects by comparing it to a prototype, the left fusiform gyrus is activated. This is an area, which is responsible for recognising abstract images. On the other hand, when we compare things to particular examples of a category, there is an activation of the left hippocampus. This field plays an important role for the storage or retrieval of memories.

Categories reduce information load

Thinking in categories or pigeonholing helps our brain in bringing order into a constantly changing world and it reduces the information load. Cognitive scientists differentiate between two main strategies which achieve this: the exemplar strategy and the prototype strategy.

When we want to find out, whether a certain animal fits into the category "bird" we would at first apply the prototype strategy and compare it to an abstract general "bird." This prototype has the defining features of the class, like a beak, feathers or the ability to fly. But when we encounter outliers or exceptions like an emu or a penguin, this strategy may be of no use. Then we apply the exemplar strategy and compare the animal to many different known examples of the category. This helps us find the right category, even for "distant relations."

Read more at Science Daily

New Meat-Eating Dino Found in Argentina

This is a skull and body reconstruction of the new dinosaur species, Murusraptor barrosaensis.
A new meat-eating dinosaur has just been discovered in Argentina, a country still known for its red meat.

Discovery of the new dinosaur, named Murusraptor barrosaensis, suggests that what is now Argentina has been dominated by carnivores for at least 80 million years. The dino is described in a paper published in the latest issue of the journal PLOS ONE.

Argentina now has the world's second-highest consumption rate of beef per capita. (Hong Kong holds the top spot.)

Rodolfo Coria from the Consejo Nacional de Investigaciones Científicas y Técnicas and Phillip Currie from the University of Alberta explained how they crafted the new dinosaur's scientific name.

"'Murus' is a Latin term for 'wall,' referring to the discovery of the specimen in the wall of a canyon; 'barrosaensis' alludes to Sierra Barrosa, the locality where it was collected," they wrote. Sierra Barrosa is an Upper Cretaceeous rock formation located at Neuquén Province, Patagonia.

They added that skeletons of turtles, crocodiles, mammals and other dinosaurs were also found at the site, along with the footprints of prehistoric birds.

They estimate that meat-munching "Wall Raptor" was young when it died, but the well-preserved remains of the dinosaur indicate that it still grew to at least 21 feet.

The new dinosaur was not just any raptor, but a megaraptor, a term used to describe large, carnivorous two-legged dinosaurs from the Cretaceous. Perhaps the most distinguishing feature of megaraptors was the 14-inch-long sickle-like claw on the thumb of each of their forelimbs. The dinosaur's other digits were clawed, too.

Megaraptors also had a tail that was probably used for quick turns and to help with balance. The bones of these dinosaurs were air-filled and bird-like. Together, the features suggest that these dinos were extremely agile hunters.

Read more at Discovery News

Hummingbirds Wired to Dodge High-Speed Collisions

It's no secret that hummingbirds are masters of aerodynamics, zooming along at high speed (up to 30 miles per hour), changing course in an instant as the objects around them dictate.

It's how they manage to move like that -- exerting such precise control -- without experiencing dangerous collisions that has been a bit of a mystery to scientists.

Researchers from the University of British Columbia (UBC) set out to solve the mystery, and the solution may lie in how the tiny birds process visual information.

To test the hummingbird's use of in-flight vision, the researchers set up a tunnel in a laboratory and projected various patterns on its sides. Then they trained cameras on the birds as they flew through the tunnel and reacted to the patterns. (Sugar water on one end of the tunnel and a feeder on the other kept the birds only too happy to make this back-and-forth journey.)

First the scientists projected patterns meant to mimic the way bees process distance when piloting through the air. They knew that bees use the speed of objects as they pass by in their field of vision in order to gauge object distance, much in the same way humans, when driving on the highway, observe more distant objects going by slowly while things close by -- say, a rest area -- zoom past.

But the birds did not react to the imagery based upon speed. Instead, the scientists observed, they used object size in the vertical axis to figure out how far away objects were, when flying left or right -- bigger meant closer while smaller meant farther away. In the test, the birds steered toward smaller imagery and away from bigger patterns.

"When objects grow in size, it can indicate how much time there is until they collide, even without knowing the actual size of the object," said the study's lead author Roslyn Dakin, UBC postdoctoral fellow, in a statement. "Perhaps this strategy allows birds to more precisely avoid collisions over the very wide range of flight speeds they use."

Read more at Discovery News

Kepler Adds 100 to Galaxy's Planet Count

Astronomers have confirmed 104 planets beyond the solar system that were spotted by NASA's revamped Kepler space telescope.

Launched in March 2009, Kepler spent four years staring at small patch of the sky looking for slight dips in the amount of light coming from about 140,000 target stars. Scientists then used the information to determine which light dips are caused by planets passing across the face of their parent stars, relative to Kepler's line of sight, as opposed to, for example, stellar flares or eclipsing binary stars.

A pointing system problem sidelined Kepler in 2013, but engineers devised a new way to operate the telescope using its two remaining gyroscopes, its thrusters and the pressure of sunlight.

For stability, the telescope needs to be oriented nearly parallel to its orbital path around the sun, which is slightly offset from Earth's orbital plane, known as the ecliptic.

Kepler now observes a portion of the sky for up to 83 days and then rotates to prevent sunlight from coming into its field of view.

In its new mission, dubbed K-2, Kepler so far has found 458 candidate planets, 127 of which have been confirmed, NASA said.

The tally includes 104 extrasolar planets confirmed this week, which brings the total number of known planets beyond the solar system, found by Kepler and other telescopes, to 3,472.

The newest members of the planet list include four worlds, ranging in size from 20 percent to 50 percent bigger than Earth, orbiting the same star.

Two of the planets, K2-72c and 72e, are properly distanced from the host star for liquid water, if it exists. Because the star is about half the size of the sun and much dimmer, its so-called "habitable zone" is closer than where Mercury's orbits the sun in our solar system.

K2-72c, which has a 15-day orbit, is about 10 percent warmer than Earth. Sibling K2-72e, which is in a 24-day orbit, is about 6 percent colder than Earth.

Read more at Discovery News

Nocturnal Primates Are Big Drinkers

Nocturnal primates not only regularly consume alcohol in fermented nectars, saps and fruits, but they also seem to love it, finds new research on two night-prowling primate species: the aye-aye and the slow loris.

Aye ayes (Daubentonia madagascariensis) are lemurs native to Madagascar that have an elongated, bony finger for detecting and extracting grubs from decaying tree trunks. They also commonly eat seeds, fruits, nectar and fungi. The slow loris, which hails from Southeast Asia, has a similar omnivore diet and is, as its name suggests, a slow mover.

Aye ayes, as well as chimpanzees, bonobos, gorillas and humans, all have a genetic mutation that improves breakdown of alcohol in the body. Together, the findings suggest that the common ancestor of humans and great apes regularly consumed naturally fermented foods and liquids, perhaps after the goods wound up on the forest floor.

The two aye ayes and slow loris involved in the new study, published in the journal Royal Society Open Science, seemed to feel no pain.

"The animals in the study appeared to like alcohol very much, suggesting some kind of sensory reward, although no signs of inebriation were observed," lead author Samuel Gochman, a sophomore at Dartmouth College, told Discovery News.

Gochman, senior author Nathaniel Dominy and co-author Michael Brown conducted multiple-choice feeding experiments with two aye ayes, "Morticia" and "Merlin," as well as a slow loris, "Dharma," at the Duke Lemur Center to test for an aversion or preference to varying concentrations of alcohol in simulated nectar. The alcohol concentrations were low -- 0 to 5 percent -- reflecting levels found in nature.

Dominy, an anthropologist and evolutionary biologist at Dartmouth, said that in nature, "some of the highest (alcohol) recordings from a wild plant come from overripe palm fruits in Panama. The levels were about 6 percent."

The researchers found that primates could detect varying concentrations of alcohol, and that they adjusted their intake of the nectar with the highest amounts. Morticia and Merlin even continued to probe the containers with the greatest amounts of alcohol long after they were emptied, implying they wanted more.

"The prevailing assumption is that alcohol is toxic, negatively affecting motor control, survival, and fitness," Gochman said. "However, calories are scarce in the environment, and alcohol is a rich source of calories for primates with high metabolisms, so there may be nutritional benefits to consuming moderate amounts of alcohol that outweigh the costs, especially if a species has evolved a digestive system that can break it down hyper-efficiently, as ours does."

It could even be that fermentation evolved, like fragrance, to attract consumers to slightly boozy edibles. Dominy explained that if consuming more nectar or fruit benefits the plant, such as via better pollination and seed dispersal, then fermentation could bring mutual benefits to the plant and consumer.

Nocturnal primates may be particularly good at finding fermented foods and liquids, since they rely on smell to find food at night. Dominy says that "alcohols are lightweight molecules that can travel far from their source, so it is possible that nocturnal primates can better detect and navigate towards fruits or nectars on the basis of smell."

The behavior could be extra advantageous for these night-loving primates, he said, since they have high metabolic demands and must fuel their bodies with calories, which alcohol is a rich source of in the wild.

Still, day-active (diurnal) primates must eat a fair amount of natural alcohol too, since all fruit contains at least trace amounts of alcohol. Primates like gibbons have a diet that is up to 95 percent fruit, and given the commonness of fermented fruits, a gibbon's regular alcohol intake could be fairly significant.

Fermented food consumption must date back to long ago, given the evolved genetic mutation, A294V. Gochman said this mutation results in a 40-fold improvement in the digestive efficiency of the ADH4 enzyme, one of several alcohol-digesting enzymes.

Robert Dudley, professor and chair of the University of California at Berkeley's Department of Integrative Science, is the author of the book The Drunken Monkey: Why We Drink and Abuse Alcohol (University of California Press, 2014).

Dudley told Discovery News that the new study "nicely documents behavioral tendencies of two basal primate species to prefer higher concentrations of alcohol within solution."

Dudley added, "It also indirectly supports the drunken monkey hypothesis, which postulates that modern-day drinking behaviors reflect ancient ecological and dietary exposure of hominids (i.e., our ancestors), and possibly of all primates, to this most widespread of the psychoactive compounds consumed by humans today."

Although we have evolved to detect, tolerate and like alcohol, based on so many years of consuming naturally fermented liquids and foods, the problem is that we now make such consumables ourselves with alcohol levels far greater than 5–6 percent. As a result, "we are producing amounts and concentrations that surpass our digestive tolerance," Dominy said.

Read more at Discovery News

Jul 19, 2016

For ancient deep-sea plankton, a long decline before extinction

A slab of rock from a study site in Nevada harbors many specimens of Metabolograptus extraordinarius, a shallow-water graptolite species, which together with some close relatives, replaced all the formerly dominant species following the end-Ordovician mass extinction.
A new study of nearly 22,000 fossils finds that ancient plankton communities began changing in important ways as much as 400,000 years before massive die-offs ensued during the first of Earth's five great extinctions.

The research, published July 18 in the Early Edition of the Proceedings of the National Academy of Sciences, focused on large zooplankton called graptolites. It suggests that the effects of environmental degradation can be subtle until they reach a tipping point, at which dramatic declines in population begin.

"In looking at these organisms, what we saw was a disruption of community structures -- the way in which the plankton were organized in the water column. Communities came to be less complex and dominated by fewer species well before the massive extinction itself," says co-author H. David Sheets, PhD, professor of physics at Canisius College and associate research professor in the Evolution, Ecology and Behavior graduate program at the University at Buffalo.

This turmoil, occurring in a time of ancient climate change, could hold lessons for the modern world, says co-author Charles E. Mitchell, PhD, professor of geology in the University at Buffalo College of Arts and Sciences.

The shifts took place at the end of the Ordovician Period some 450 million years ago as the planet transitioned from a warm era into a cooler one, leading eventually to glaciation and lower sea levels.

"Our research suggests that ecosystems often respond in stepwise and mostly predictable ways to changes in the physical environment -- until they can't. Then we see much larger, more abrupt, and ecologically disruptive changes," Mitchell says. "The nature of such tipping point effects are hard to foresee and, at least in this case, they led to large and permanent changes in the composition of the oceans' living communities.

"I think we need to be quite concerned about where our current ocean communities may be headed or we may find ourselves at the tail end of a similar event -- a sixth mass extinction, living in a very different world than we would like."

The study was a partnership between Canisius, UB, St. Francis Xavier University, Dalhousie University and The Czech Academy of Sciences.

A long slide toward oblivion

In considering mass extinction, there is perhaps the temptation to think of such events as rapid and sudden: At one moment in history, various species are present, and the next they are not.

This might be the conclusion you'd draw if you examined only whether different species of graptolites were present in the fossil record in the years immediately preceding and following the Ordovician extinction.

"If you just looked at whether they were present -- if they were there or not -- they were there right up to the brink of the extinction," Sheets says. "But in reality, these communities had begun declining quite a while before species started going extinct."

The research teased out these details by using 21,946 fossil specimens from areas of Nevada in the U.S. and the Yukon in Canada that were once ancient sea beds to paint a picture of graptolite evolution.

The analysis found that as ocean circulation patterns began to shift hundreds of thousands of years before the Ordovician extinction, graptolite communities that previously included a rich array of both shallow- and deep-sea species began to lose their diversity and complexity.

Deep-water graptolites became progressively rarer in comparison to their shallow-water counterparts, which came to dominate the ocean.

"There was less variety of organisms, and the rare organisms got rarer," Sheets says. "In the aftermath of a forest fire in the modern world, you might find that there are fewer organisms left -- that the ecosystem just doesn't have the same structure and richness as before. That's the same pattern we see here."

Read more at Science Daily

Paleontology: Aftermath of a mass extinction

A specimen of the newly identified fossil species Ticinolepis crassidens (above) and of the species Ticinolepis longaeva.
A new study of fossil fishes from Middle Triassic sediments on the shores of Lake Lugano provides new insights into the recovery of biodiversity following the great mass extinction event at the Permo-Triassic boundary 240 million years ago.

The largest episode of mass extinction in the history of the Earth, which led to the demise of about 90% of marine organisms and a majority of terrestrial species, took place between the Late Permian and Early Triassic, around 240 million years ago. How long it took for biological communities to recover from such a catastrophic loss of biodiversity remains the subject of controversial debate among paleontologists. A new study of fossil fishes from Middle Triassic strata on the shores of Lake Lugano throws new light on the issue.

The study, undertaken by researchers led by Dr. Adriana López-Arbarello, who is a member of the GeoBiocenter at Ludwig-Maximilians-Universitaet (LMU) in Munich and the Bavarian State Collection for Paleontology and Geology, suggests that the process of recovery was well underway within a few million years. The authors, including Dr. Heinz Furrer of Zurich University and Dr. Rudolf Stockar of the Museo Cantonale di Storia Naturale in Lugano, who led the excavations at the sites, and Dr. Toni Bürgin of the Naturmuseum St. Gallen report their findings in the journal PeerJ.

The fossil fishes analyzed by López-Arbarello and her colleagues originate from Monte San Giorgio in the canton Ticino in Switzerland, which is one of the most important sources of marine fossils from the Middle Triassic in the world. The Monte San Giorgio rises to an altitude of 1000 m on the promontory that separates the southern arms of Lake Lugano in the Southern Swiss Alps. But in the Middle Triassic, it was part of a shallow basin dotted with islands fringed by lagoons, which were separated by reefs from the open sea. "

The particular significance of its fossil fauna lies in the careful stratigraphic work that has accompanied the excavations here. The positions of each of the fossil finds discovered here have been documented to the centimeter," says Adriana López-Arbarello. On the basis of detailed anatomical studies of new material and a taxonomic re-evaluation of previously known specimens from the locality, she and her colleagues have identified a new genus of fossil neopterygians, which they name Ticinolepis. The Neopterygii include the teleost fishes, which account for more than half of all extant vertebrate species. However, the new fossil species are assigned to the second major group of neopterygians, the Holostei, of which only a handful of species survives today. The researchers assign two new fossil species to the genus Ticinolepis, namely T. longaeva and T. crassidens, which occur in different sedimentary beds within the so-called Besano Formation on Monte San Giorgio.

Read more at Science Daily

Ancient rocks reveal how Earth recovered from mass extinction

Analysis of rocks unearthed in Oman that were formed in an ancient ocean around the time of Earth's greatest mass extinction have helped explain why life on Earth took so long to recover.
Scientists have shed light on why life on Earth took millions of years to recover from the greatest mass extinction of all time.

The study provides fresh insight into how Earth's oceans became starved of oxygen in the wake of the event 252 million years ago, delaying the recovery of life by five million years.

Findings from the study are helping scientists to better understand how environmental change can have disastrous consequences for life on Earth.

The Permian-Triassic Boundary extinction wiped out more than 90 per cent of marine life and around two thirds of animals living on land. During the recovery period, Earth's oceans became starved of oxygen -- conditions known as anoxia.

Previous research suggested the mass extinction and delayed recovery were linked to the presence of anoxic waters that also contained high levels of harmful compounds known as sulphides.

However, researchers say anoxic conditions at the time were more complex, and that this toxic, sulphide-rich state was not present throughout all the world's oceans.

The team, led by researchers at the University of Edinburgh, used precise chemical techniques to analyse rocks unearthed in Oman that were formed in an ancient ocean around the time of the extinction.

Data from six sampling sites, spanning shallow regions to the deeper ocean, reveal that while the water was lacking in oxygen, toxic sulphide was not present. Instead, the waters were rich in iron.

The finding suggests that iron-rich, low oxygen waters were a major cause of the delayed recovery of marine life following the mass extinction.

The study also shows how oxygen levels varied at different depths in the ocean. While low oxygen levels were present at some depths and restricted the recovery of marine life, shallower waters contained oxygen for short periods, briefly supporting diverse forms of life.

The precise cause of the long recovery period remains unclear, but increased run-off from erosion of rocks on land -- caused by high global temperatures -- likely triggered anoxic conditions in the oceans, researchers say.

The study, published in the journal Nature Communications, was funded by the Natural Environment Research Council and the International Centre for Carbonate Reservoirs. The work is a contribution to the UNESCO International Geoscience Programme. It was carried out in collaboration with the Universities of Leeds, Gratz, Bremen and Vienna University.

Dr Matthew Clarkson, of the University of Edinburgh's School of GeoSciences, who led the study, said: "We knew that lack of oxygen in the oceans played a key role in the extinction and recovery processes, but we are still discovering how exactly it was involved. Our findings about the chemistry of the ocean at the time provide us with a clearer picture of how this complex process delayed the recovery of life for so long."

Read more at Science Daily

Ozone Layer Protections Actually Warmed the Planet

Back in 1987, 60 countries signed the Montreal Protocol, a landmark agreement to phase out gases called chlorofluorocarbons, or CFCs, which were used in refrigerators, air conditioners, and aerosol cans, because they were eroding the atmospheric ozone layer that protects us against getting too much solar radiation.

Unfortunately, this caused a big problem that no one foresaw at the time. The hydrofluorocarbons (HFCs) that replaced the CFCs in those devices didn't hurt the ozone layer. But HFCs were potent greenhouse gases that contributed disproportionately to global warming, which wasn't getting as much attention as it is now.

That's why diplomats and officials from various countries have assembled in Vienna this week to amend the Montreal Protocol and phase out HFCs, which are vastly more powerful than carbon dioxide when it comes to greenhouse effects.

The Institute for Sustainable Development says that HFCs are 1,300 times more potent than a similar quantity of C02, when it comes to warming the planet. A 2015 article published in the Journal of Geophysical Research Atmospheres reported that by 2050, one particular type of HFC, HFC-134a, could add as much as 19 percent to the warming effect of carbon dioxide.

Veerabhadran Ramanathan, a climate scientist at the Scripps Institution of Oceanography, told the Washington Post that "by banning HFCs, you prevent another disaster downstream."

Another expert, former Clinton Administration climate change adviser Paul Bledsoe, said such a ban would reduce global warming in the 21st Century by 0.9 degrees Fahrenheit.

The U.S. Environmental Protection Agency already has approved several alternative refrigerants that could be used to replace HFCs.

From Discovery News

2 Newfound Alien Planets Could Support Life

NASA's Kepler space telescope recently discovered 104 exoplanets, including four possibly rocky worlds that circle a red dwarf star called K2-72.
NASA's Kepler space telescope has spotted four possibly rocky alien planets orbiting the same star, and two of these newfound worlds might be capable of supporting life.

The four exoplanets circle a red dwarf — a star smaller and dimmer than the sun — called K2-72, which lies 181 light-years from Earth in the Aquarius constellation. All four worlds are between 20 percent and 50 percent wider than Earth, making them good candidates to be rocky, discovery team members said.

Two of the four planets, known as K2-72c and K2-72e, appear to be in the star's "habitable zone" — that just-right range of distances at which liquid water can exist on a world's surface, the scientists added.

Because K2-72 is a red dwarf, its habitable zone is much closer in than that of the sun. For example, K2-72c completes one orbit every 15 Earth days, yet it is likely just 10 percent warmer than our planet. K2-72e has a 24-Earth-day year, and it's about 6 percent colder than Earth, the scientists said. (All four newfound planets complete an orbit in 24 Earth days or less, making them closer to K2-72 than Mercury is to the sun.)

The K2-72 planets are among 104 alien worlds recently discovered by the Kepler telescope during its bounce-back K2 mission. Study leader Ian Crossfield, of the University of Arizona's Lunar and Planetary Laboratory, first announced this haul in January, during a presentation at the 227th Meeting of the American Astronomical Society in Kissimmee, Florida, and the results were just published online in The Astrophysical Journal Supplement Series.

Kepler finds alien planets by noticing the tiny brightness dips they cause when they cross their host stars' faces from the spacecraft's perspective. This work requires incredibly precise pointing — an ability Kepler lost in May 2013 when the second of its four orientation-maintaining reaction wheels failed.

However, Kepler team members soon figured out a way to stabilize the telescope using sunlight pressure and the two remaining reaction wheels. In 2014, Kepler embarked on a new mission called K2, during which it is observing a variety of cosmic objects and phenomena, including exoplanets.

But Kepler's planet hunt is quite different this time around. Whereas the observatory stared continuously at one small patch of sky during its original mission, Kepler is now peering at different regions during a series of 80-day "campaigns."

Read more at Discovery News

Jul 18, 2016

A glimpse inside the atom

Atomic orbitals of carbon atoms in graphene.
An electron microscope can't just snap a photo like a mobile phone camera can. The ability of an electron microscope to image a structure -- and how successful this imaging will be -- depends on how well you understand the structure. Complex physics calculations are often needed to make full use of the potential of electron microscopy. An international research team led by TU Wien's Prof. Peter Schattschneider set out to analyse the opportunities offered by EFTEM, that is energy-filtered transmission electron microscopy. The team demonstrated numerically that under certain conditions, it is possible to obtain clear images of the orbital of each individual electron within an atom. Electron microscopy can therefore be used to penetrate down to the subatomic level -- experiments in this area are already planned. The study has now been published in the physics journal Physical Review Letters.

In search of the electron orbital

We often think of atomic electrons as little spheres that circle around the nucleus of the atom like tiny planets around a sun. This image is barely reflected in reality, however. The laws of quantum physics state that the position of an electron cannot be clearly defined at any given point in time. The electron is effectively smeared across an area close to the nucleus. The area that could contain the electron is called the orbital. Although it has been possible to calculate the shape of these orbitals for a long time, efforts to image them with electron microscopes have been unsuccessful to date.

"We have calculated how we might have a chance of visualising orbitals with an electron microscope," says Stefan Löffler from the University Service Centre for Transmission Electron Microscopy (USTEM) at TU Wien. "Graphene, which is made of just one single layer of carbon atoms, is an excellent candidate for this task. The electron ray is able to pass easily through the graphene with hardly any elastic scattering. An image of the graphene structure can be created with these electrons."

Researchers have been aware of the principle of "energy-filtered transmission electron microscopy" (EFTEM) for some time. EFTEM can be used to create quite specific visualisations of certain kinds of atoms whilst blocking out the others. For this reason, it is often used today to analyse the chemical composition of microscopic samples. "The electrons shot through the sample can excite the sample's atoms," explains Stefan Löffler. "This costs energy, so when the electrons emerging emerge from the sample, they are slower than when they entered it. This velocity and energy change is characteristic for certain excitations of electron orbitals within the sample."

After the electrons have passed through the sample, a magnetic field sorts the electrons by energy. "A filter is used to block out electrons that aren't of interest: the recorded image contains only those electrons that carry the desired information."

Defects can be helpful

The team used simulations to investigate how this technique could help reach a turning point in the study of electron orbitals. While doing so, they discovered something that actually facilitated the imaging of individual orbitals: "The symmetry of the graphene has to be broken," says Stefan. "If, for instance, there is a hole in the graphene structure, the atoms right beside this hole have a slightly different electronic structure, making it possible to image the orbitals of these atoms. The same thing can happen if a nitrogen atom rather than a carbon atom is found somewhere in the graphene. When doing this, it's important to focus on the electrons found within a narrow and precise energy window, minimise certain aberrations of the electromagnetic lens and, last but not least, use a first-rate electron microscope." All of these issues can be overcome, however, as the research group's calculations show.

Read more at Science Daily

New discoveries about photosynthesis may lead to solar cells of the future

For the first time, researchers have successfully measured in detail the flow of solar energy, in and between different parts of a photosynthetic organism. The result is a first step in research that could ultimately contribute to the development of technologies that use solar energy far more efficiently than what is currently possible.

For about 80 years, researchers have known that photochemical reactions inside an organism do not occur in the same place as where it absorbs sunlight. What has not been known, however, is how and along what routes the solar energy is transported into the photosynthetic organism -- until now.

"Not even the best solar cells that we as humans are capable of producing can be compared to what nature performs in the first stages of energy conversion. That is why new knowledge about photosynthesis will become useful for the development of future solar technologies," says Donatas Zigmantas, Faculty of Science at Lund University, Sweden.

Together with his colleagues Jakub Dostál, Lund University, and Jakub Pšenčík, Charles University in Prague, Donatas Zigmantas has studied the photosynthesis of bacterial cells. Using ultrafast spectroscopy -- a measurement method that uses light to study molecules etc. -- they were able to locate the routes along which solar energy is transported. The routes run both within and between the components of a photosynthetic cell. According to the researchers, their discovery demonstrates how the biological machinery is connected.

The research results show that the transport of solar energy is much more efficient within, than between, different cell components. It limits the transfer of energy between the components and thereby also the efficiency of the entire photosynthetic energy conversion process.

"We have identified the transport routes as well as the bottlenecks that cause congestion in the photosynthetic energy conversion. In the future, this knowledge can be used within solar cell technology," says Donatas Zigmantas.

So far this is basic research -- more studies of how energy is transported in both natural and artificial systems are needed before the results can be turned into practice.

Read more at Science Daily

Researchers build a crawling robot from sea slug parts and a 3-D printed body

A sea slug's buccal I2 muscle powers this biohybrid robot as it crawls like a sea turtle. The body and arms are made from a 3-D printed polymer.
Researchers at Case Western Reserve University have combined tissues from a sea slug with flexible 3-D printed components to build "biohybrid" robots that crawl like sea turtles on the beach.

A muscle from the slug's mouth provides the movement, which is currently controlled by an external electrical field. However, future iterations of the device will include ganglia, bundles of neurons and nerves that normally conduct signals to the muscle as the slug feeds, as an organic controller.

The researchers also manipulated collagen from the slug's skin to build an organic scaffold to be tested in new versions of the robot.

In the future, swarms of biohybrid robots could be released for such tasks as locating the source of a toxic leak in a pond that would send animals fleeing, the scientists say. Or they could search the ocean floor for a black box flight data recorder, a potentially long process that may leave current robots stilled with dead batteries.

"We're building a living machine -- a biohybrid robot that's not completely organic -- yet," said Victoria Webster, a PhD student who is leading the research. Webster will discuss mining the sea slug for materials and constructing the hybrid, which is a little under 2 inches long, at the Living Machines conference in Edinburgh, Scotland, this week.

Webster worked with Roger Quinn, the Arthur P. Armington Professor of Engineering and director of Case Western Reserve's Biologically Inspired Robotics Laboratory; Hillel Chiel, a biology professor who has studied the California sea slug for decades; Ozan Akkus, professor of mechanical and aerospace engineering and director of the CWRU Tissue Fabrication and Mechanobiology Lab; Umut Gurkan, head of the CWRU Biomanufacturing and Microfabrication Laboratory, undergraduate researchers Emma L. Hawley and Jill M. Patel and recent master's graduate Katherine J. Chapin

By combining materials from the California sea slug, Aplysia californica, with three-dimensional printed parts, "we're creating a robot that can manage different tasks than an animal or a purely manmade robot could," Quinn said.

The researchers chose the sea slug because the animal is durable down to its cells, withstanding substantial changes in temperature, salinity and more as Pacific Ocean tides shift its environment between deep water and shallow pools. Compared to mammal and bird muscles, which require strictly controlled environments to operate, the slug's are much more adaptable.

For the searching tasks, "we want the robots to be compliant, to interact with the environment," Webster said. "One of the problems with traditional robotics, especially on the small scale, is that actuators -- the units that provide movement -- tend to be rigid."

Muscle cells are compliant and also carry their own fuel source -- nutrients in the medium around them. Because they're soft, they're safer for operations than nuts-and-bolts actuators and have a much higher power-to-weight ratio, Webster said.

The researchers originally tried using muscle cells but changed to using the entire I2 muscle from the mouth area, or buccal mass. "The muscle already had the optimal structure and form to provide the function and strength needed," Chiel said.

Akkus said, "When we integrate the muscle with its natural biological structure, it's hundreds to 1,000 times better."

In their first robots, the buccal muscle, which naturally has two "arms," is connected to the robots printed polymer arms and body. The robot moves when the buccal muscle contracts and releases, swinging the arms back and forth. In early testing, the bot pulled itself about 0.4 centimeters per minute.

To control movement, the scientists are turning to the animal's own ganglia. They can use either chemical or electrical stimuli to induce the nerves to contract the muscle.

"With the ganglia, the muscle is capable of much more complex movement, compared to using a manmade control, and it's capable of learning," Webster said.

The team hopes to train ganglia to move the robot forward in response to one signal and backward in response to a second.

With the goal of making a completely organic robot, Akkus' lab gelled collagen from the slug's skin and also used electrical currents to align and compact collagen threads together, to build a lightweight, flexible, yet strong scaffold.

Read more at Science Daily

2,000-Year-Old Dog Graveyard Found in Siberia

Archaeologists have discovered a prehistoric dog graveyard at a 2,000-year-old village near the Arctic Circle in Russia's Siberia.
The carefully buried remains of five dogs were recently found in a 2,000-year-old doggy graveyard near the Arctic Circle in Siberia, according to archaeologists.

This discovery at the Ust-Polui archaeological site, in Salekhard, Russia, reveals close relationships between the region's people and their animal "best friends" two millennia B.C. The dogs likely served as pets, workers and sources of food — and possibly as sacrificial offerings in religious ceremonies, the researchers said.

"The role of dogs at Ust-Polui is really complex and variable," Robert Losey, an archaeologist at the University of Alberta in Canada, wrote in an email to Live Science from Salekhard, where he is carrying out fieldwork at Ust-Polui.

"The most striking thing is that the dog remains are really abundant compared to all other sites in the Arctic — there are over 115 dogs represented at the site," Losey said. "Typically, sites have only a few dog remains — 10 at most."

The dogs were likely involved in various tasks in the ancient Arctic village, including pulling sleds, he said. The remains of two sleds, as well as a carved bone knife handle thought to depict a sled dog in a harness, have been found at the site.

"Some [dogs] were probably also used in hunting, for reindeer and birds, the remains of which were both abundant at the site," Losey said.

Parts of a reindeer harness had also been found at Ust-Polui, he added, and dogs may have been used to herd reindeer, as is still done today by some communities in the region.

But despite evidence that the dogs worked with people and other animals, it was also clear that many of the dogs at Ust-Polui had been butchered and probably eaten, Losey said. Many of the dog bones had cut marks on them, and were found scattered around the site in the same way as the bones of other food animals, such as deer and birds, he said.

Some of the dog consumption may have been related to sacrifices or rituals, or even feasting, Losey noted. In fact, "at one place in the site, the heads of 15 dogs were piled together, all with their brain cases broken open in the same manner," he said.

He added that the sacrificing of dogs was well documented among indigenous people in this region of Siberia, "and is done to appease spirits, or to ensure community health, and so on."

But though it might have been a dog's life for most of the canine population of Ust-Polui, a few top dogs seem to have enjoyed special treatment, the archaeologists said.

Of the more than 115 dogs that archaeologists identified among the animal bones at Ust-Polui, the remains of just five dogs were found carefully buried in a group near one edge of the site, Losey said.

This separation likely indicates close bonds between some people and some dogs in the ancient village, he said.

Each of the prehistoric doggy graves contained the entire dog skeleton, laid on its side in a shallow pit, similar to three human burials at the site, and they showed no signs of butchery or of being intentionally killed, the researchers found.

"The only thing that distinguishes them from the human burials is their location. No other animals at Ust-Polui were treated like this," Losey said.

Losey started working with the dog remains from Ust-Polui three years ago, as part of his work studying the ancient relationships between people and dogs in the world's northern regions.

Read more at Discovery News

Jul 17, 2016

Health benefits of Pokémon Go

Pokémon Go being played.
Do you want to be the very best, like no one ever was? Real-life positive health consequences of playing Pokémon Go -- a new GPS-based augmented reality game -- are happening across the nation. According to Matt Hoffman, DNP, clinical assistant professor at the Texas A&M College of Nursing, this quest to "catch 'em all" is great news for public health.

I will travel across the land, searching far and wide

Players, known as "trainers," download the Pokémon Go game to their smartphones. To progress in the game, trainers must walk around to find and catch Pokémon and access specific locations called Pokéstops -- where Pokéballs and other useful items are collected. Poké eggs are among the things that can be collected at these locations. Getting to Pokéstops, catching different Pokémon and hatching the Poké eggs requires walking; lots of walking.

"Playing the game is a lot of fun, and it has been a catalyst to get people moving," said Hoffman who has been affectionately dubbed the "Pokémon Professor" by co-workers.

"What began as just playing the game has now become a hobby for me that provides certain health benefits," Hoffman continued. "I've spent an hour or two at a time venturing around the community to find Pokéstops. And, to hatch one egg, a trainer must walk anywhere from one to six miles. There's no doubt about it, I am exercising more as a result of playing the game, and I am enjoying it."

Hoffman isn't alone. Estimates of the number of Pokémon Go daily users range from nine to 21 million people, and this user base is growing daily. In addition to inspiring exercise, playing Pokémon Go may have additional benefits.

Pokémon, (gotta catch'em all!) it's you and me

"There is a sense of community when trainers converge in search of Pokémon, or when they gather together at Pokéstops," Hoffman said. "The game is bringing people together, providing opportunity for social interaction and increasing our sense of belonging, which can have a positive impact on our emotional and mental health."

Additionally, families may find that Pokémon Go lessens the technology tension that divides the generations. "This is a relatively non-violent game, and I have seen families walking around playing the game together," Hoffman said. "Or, it encourages parents to go outside with their children while they play. Pokémon Go has the ability to transport families away from an evening on the couch to walking around the neighborhood."

You teach me and I'll teach you

Hoffman said playing the game has even broadened his sense of curiosity and knowledge about his local community. "I discovered new experiences within my community because the game has led me to areas that I haven't explored, or, previously only driven through," he said. "Additionally, I've met many interesting people while playing the game, and I enjoy seeing the variation in the character designs and abilities."

Come with me, the time is right, there's no better team

Multiply the number of Pokémon Go players by the number of kilometers they must travel to progress in the game, and the chances of negative consequences increase. "We often hear of people falling off curbs or sustaining injuries as a result of staring at their phones and not paying attention to their surroundings," Hoffman said. "It's good to always keep safety and best practices in mind."

Hoffman emphasized players watch where they walk and be aware of surroundings when playing. There is safety in numbers, and he encourages playing with friends as a team.

Read more at Science Daily

Victim's Ghost Seen in Accident Photo? Unlikely

A photo taken at the scene of a fatal motorcycle crash in Kentucky has gone viral this week, with many claiming they can see the accident victim's spirit leaving his body.

The image, showing what seems to be a gray or white vertical form in the air above two ambulances, was photographed and shared on social media by Kentucky resident Saul Vazquez.

"I pulled over roll the passenger side window and snap the picture," Mr. Vazquez posted on his Facebook post of the photo, which as of today has nearly 9,000 shares.

A People magazine online article was headlined "Photo of Fatal Accident Become Online Sensation Over Claims It Shows Victim's Spirit." Others have suggested it's not a spirit but instead an angel. Stories of miracles or seemingly supernatural events at the scene of accidents are not uncommon; last year police officers who helped rescue a baby from an overturned car in a Utah river claimed that they heard an unexplained voice calling from the car—despite the fact that the mother had been dead for hours.

There are several reasons to suspect that the image may not be paranormal, but the best (and most obvious) reason to doubt that the whitish blur is the spirit of the accident victim appears in the news story about the incident: "He [the motorcylist] was transported to the hospital where he later died." Since the motorcyclist wasn't dead when the photo was taken, it would seem very unlikely that his spirit would be leaving his body at that time.

If spirits (or angels) can be photographed at scenes of tragic accidents—especially those involving many victims—then they should appear regularly. News photos and video of train, plane, and bus accidents, for example, should reveal ghostly images in and around the wreckage. In fact, if the soul leaves the body at death (as theology and ghost folklore suggest), then hospitals—not graveyards nor haunted houses—should be filled with ghosts and blurry white images in the hallways and emergency rooms.

The idea that the soul can somehow be quantified or recorded at the time of death goes back over a century. The most famous scientific experiment on that topic was conducted by Dr. Duncan MacDougall, who in 1907 tried to measure the weight of the soul. He weighed a half-dozen terminally ill patients before, during, and after death, concluding that there was an average of 21 grams difference in the weight of the bodies before and after death. His experiments were badly designed, however, with a tiny sample size and crude measurement tools. More modern measurements find no such effect, though the myth that the human soul weighs 21 grams remains today.

So if the vertical whitish thing in the photo isn't a ghost, what is it?

Vazquez has denied that the image has been altered, and there's no reason to think it has. It's much more likely to be an ordinary object that has taken on a spooky context because of the circumstances; in other words that same photo could likely have been taken at that same spot a day earlier, and no one would have associated it with anything odd or tragic.

Writer Hemant Mehta offered the following explanation on his blog: "It could easily be a discolored tree trunk. Seriously. I pulled up a Google Maps image of Highway 15 near Stanton, Kentucky where the accident took place. I don't know if this is the exact spot, but it was *very* easy to find a discolored tree trunk in the image."

It's difficult to tell what exactly the image is, but the image shows other foliage emerging from the shade of the trees in the same area; a tree trunk or light-colored branch is a real possibility. It could also be smoke from the wreck, though the motorcycle seems to be off to one side.

In any event, it's noteworthy that apparently no one at the scene reported seeing anything unusual, nor the supposed apparition just above them.

Read more at Discovery News