Laziness helped lead to extinction of Homo erectus

This is Dr. Ceri Shipton on site at Saffaqah in central Saudi Arabia.

New archaeological research from The Australian National University (ANU) has found that Homo erectus, an extinct species of primitive humans, went extinct in part because they were 'lazy'.

An archaeological excavation of ancient human populations in the Arabian Peninsula during the Early Stone Age, found that Homo erectus used 'least-effort strategies' for tool making and collecting resources.

This 'laziness' paired with an inability to adapt to a changing climate likely played a role in the species going extinct, according to lead researcher Dr Ceri Shipton of the ANU School of Culture, History and Language.

"They really don't seem to have been pushing themselves," Dr Shipton said.

"I don't get the sense they were explorers looking over the horizon. They didn't have that same sense of wonder that we have."

Dr Shipton said this was evident in the way the species made their stone tools and collected resources.

"To make their stone tools they would use whatever rocks they could find lying around their camp, which were mostly of comparatively low quality to what later stone tool makers used," he said.

"At the site we looked at there was a big rocky outcrop of quality stone just a short distance away up a small hill.

"But rather than walk up the hill they would just use whatever bits had rolled down and were lying at the bottom.

"When we looked at the rocky outcrop there were no signs of any activity, no artefacts and no quarrying of the stone.

"They knew it was there, but because they had enough adequate resources they seem to have thought, 'why bother?'."

This is in contrast to the stone tool makers of later periods, including early Homo sapiens and Neanderthals, who were climbing mountains to find good quality stone and transporting it over long distances.

Dr Shipton said a failure to progress technologically, as their environment dried out into a desert, also contributed to the population's demise.

"Not only were they lazy, but they were also very conservative," Dr Shipton said.

"The sediment samples showed the environment around them was changing, but they were doing the exact same things with their tools.

"There was no progression at all, and their tools are never very far from these now dry river beds. I think in the end the environment just got too dry for them."

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Blocking sunlight to cool Earth won't reduce crop damage from global warming

If volcanic eruptions cool Earth by dumping aerosols into the atmosphere, can we purposely inject aerosols into our atmosphere to cool the planet and mitigate the impact of climate change?

Injecting particles into the atmosphere to cool the planet and counter the warming effects of climate change would do nothing to offset the crop damage from rising global temperatures, according to a new analysis by University of California, Berkeley, researchers.

By analyzing the past effects of Earth-cooling volcanic eruptions, and the response of crops to changes in sunlight, the team concluded that any improvements in yield from cooler temperatures would be negated by lower productivity due to reduced sunlight. The findings have important implications for our understanding of solar geoengineering, one proposed method for helping humanity manage the impacts of global warming.

"Shading the planet keeps things cooler, which helps crops grow better. But plants also need sunlight to grow, so blocking sunlight can affect growth. For agriculture, the unintended impacts of solar geoengineering are equal in magnitude to the benefits," said lead author Jonathan Proctor, a UC Berkeley doctoral candidate in the Department of Agricultural and Resource Economics. "It's a bit like performing an experimental surgery; the side-effects of treatment appear to be as bad as the illness."

"Unknown unknowns make everybody nervous when it comes to global policies, as they should," said Solomon Hsiang, co-lead author of the study and Chancellor's Associate Professor of Public Policy at UC Berkeley. "The problem in figuring out the consequences of solar geoengineering is that we can't do a planetary-scale experiment without actually deploying the technology. The breakthrough here was realizing that we could learn something by studying the effects of giant volcanic eruptions that geoengineering tries to copy."

Hsiang is director of UC Berkeley's Global Policy Laboratory, where Proctor is a doctoral fellow.

Proctor and Hsiang will publish their findings online in the journal Nature on August 8.

Some people have pointed to past episodes of global cooling caused by gases emitted during massive volcanic eruptions, such as Mt. Pinatubo in the Philippines in 1991, and argued that humans could purposely inject sulfate aerosols into the upper atmosphere to artificially cool Earth and alleviate the greenhouse warming caused by increased levels of carbon dioxide. Aerosols -- in this case, minute droplets of sulfuric acid -- reflect a small percentage of sunlight back into space, reducing the temperature a few degrees.

"It's like putting an umbrella over your head when you're hot," Proctor said. "If you put a global sunshade up, it would slow warming."

Pinatubo, for example, injected about 20 million tons of sulfur dioxide into the atmosphere, reducing sunlight by about 2.5 percent and lowering the average global temperature by about half a degree Celsius (nearly 1 degree Fahrenheit).

The team linked maize, soy, rice and wheat production from 105 countries from 1979-2009 to global satellite observations of these aerosols to study their effect on agriculture. Pairing these results with global climate models, the team calculated that the loss of sunlight from a sulfate-based geoengineering program would cancel its intended benefits of protecting crops from damaging extreme heat.

"It's similar to using one credit card to pay off another credit card: at the end of the day, you end up where you started without having solved the problem," Hsiang said.

Some earlier studies suggested that aerosols might improve crop yields also by scattering sunlight and allowing more of the sun's energy to reach interior leaves typically shaded by upper canopy leaves. This benefit of scattering appears to be weaker than previously thought.

"We are the first to use actual experimental and observational evidence to get at the total impacts that sulfate-based geoengineering might have on yields," Proctor said. "Before I started the study, I thought the net impact of changes in sunlight would be positive, so I was quite surprised by the finding that scattering light decreases yields."

Despite the study's conclusions, Proctor said, "I don't think we should necessarily write off solar geoengineering. For agriculture, it might not work that well, but there are other sectors of the economy that could potentially benefit substantially."

Proctor and Hsiang noted that their methods could be used to investigate the impact of geoengineering on other segments of the economy, human health and the functioning of natural ecosystems.

They did not address other types of geoengineering, such as capture and storage of carbon dioxide, or issues surrounding geoengineering, such as its impact on Earth's protective ozone layer and who gets to set Earth's thermostat.

"Society needs to be objective about geoengineering technologies and develop a clear understanding of the potential benefits, costs and risks," Proctor said. "At present, uncertainty about these factors dwarfs what we understand."

The authors emphasize the need for more research into the human and ecological consequences of geoengineering, both good and bad.

"The most certain way to reduce damages to crops and, in turn, people's livelihood and well-being, is reducing carbon emissions," Proctor said.

"Perhaps what is most important is that we have respect for the potential scale, power and risks of geoengineering technologies," Hsiang said. "Sunlight powers everything on the planet, so we must understand the possible outcomes if we are going to try to manage it."

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Ultrahot planets have starlike atmospheres

These simulated views of the ultrahot Jupiter WASP-121b show what the planet might look like to the human eye from five different vantage points, each illuminated to different degrees by its parent star. The images were made with a computer simulation being used to help scientists understand the atmospheres of these planets. Ultrahot Jupiters reflect almost no light, much like charcoal. However, their daysides have temperatures of between 3,600 F and 5,400 F, so they produce their own glow like a hot ember. The orange color in this simulated image thus comes from the planet's own heat.

Recent observations by NASA's Hubble and Spitzer space telescopes of ultrahot Jupiter-like planets have perplexed theorists. The spectra of these planets have suggested they have exotic -- and improbable -- compositions.

However, a new study just published by a research team that includes Arizona State University astrophysicist Michael Line, an assistant professor in ASU's School of Earth and Space Exploration, proposes an explanation -- that these gas-rich planets have compositions that are basically normal, going by what is known about planet formation. What's different about them is that the atmospheres on their daysides look more like the atmosphere of a star than a planet.

"Interpreting the spectra of the hottest of these Jupiter-like planets has posed a thorny puzzle for researchers for years," Line said.

The biggest puzzle is why water vapor appears to be missing from these worlds' atmospheres, when it is abundant in similar but slightly cooler planets.

According to the new study, ultrahot Jupiters do in fact possess the ingredients for water (hydrogen and oxygen atoms). But due to the strong radiation on the planet's daysides, temperatures there go high enough that water molecules are completely torn apart.

With ultrahot Jupiters orbiting extremely close to their stars, one side of the planet faces the star perpetually, while the nightside is gripped by endless darkness.

Dayside temperatures reach between 3,600 to 5,400 degrees Fahrenheit (2,000 to 3,000 degrees Celsius), ranking ultrahot Jupiters among the hottest exoplanets known. And nightside temperatures are around 1,800 degrees Fahrenheit cooler.

Star-planet hybrids

Among the growing catalogue of planets outside our solar system -- known as exoplanets -- ultrahot Jupiters have stood out as a distinct class for about a decade.

"The daysides of these worlds are furnaces that look more like a stellar atmosphere than a planetary atmosphere," said Vivien Parmentier, an astrophysicist at Aix Marseille University in France and lead author of the new study published in Astronomy and Astrophysics. "In this way, ultrahot Jupiters stretch out what we think planets should look like."

While telescopes like Spitzer and Hubble can gather some information about the daysides of ultrahot Jupiters, their nightsides are difficult for current instruments to probe.

The new paper proposes a model for what might be happening on both the illuminated and dark sides of these planets. The model is based largely on observations and analysis from three recently published studies, coauthored by Parmentier, Line, and others, that focus on three ultrahot Jupiters, WASP-103b, WASP-18b, and HAT-P-7b.

The new study suggests that fierce winds driven by heating may blow the torn-apart water molecules into the planets' cooler nightside hemispheres. There the atoms can recombine into molecules and condense into clouds, all before drifting back into the dayside to be ripped apart again.

Family resemblance?

Hot Jupiters were the first widely discovered kind of exoplanet, starting back in the mid-1990s. These are cooler cousins to ultrahot Jupiters, with dayside temperatures below 3,600 degrees Fahrenheit (2,000 Celsius).

Water has proven to be common in their atmospheres, and thus when ultrahot Jupiters began to be found, astronomers expected them to show water in their atmospheres as well. But water turned out to be missing on their easily observed daysides, which got theorists looking at alternative, even exotic, compositions.

One hypothesis for why water appeared absent in ultrahot Jupiters has been that these planets must have formed with very high levels of carbon instead of oxygen. Yet this idea could not explain the traces of water sometimes detected at the dayside-nightside boundary.

To break the logjam, the research team took a cue from well-established physical models of stellar atmospheres, as well as "failed stars," known as brown dwarfs, whose properties overlap somewhat with hot and ultrahot Jupiters.

"Unsatisfied with exteme compositions, we thought harder about the problem," Line said. "Then we realized that many earlier interpretations were missing some key physics and chemistry that happens at these ultrahot temperatures."

The team adapted a brown dwarf model developed by Mark Marley, one of the paper's co-authors and a research scientist at NASA's Ames Research Center in Silicon Valley, California, to the case of ultrahot Jupiters. Treating the atmospheres of ultrahot Jupiters more like blazing stars than conventionally colder planets offered a way to make sense of the Spitzer and Hubble observations.

"With these studies, we are bringing some of the century-old knowledge gained from studying the astrophysics of stars, to the new field of investigating exoplanetary atmospheres," Parmentier said.

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Neuroscientists get at the roots of pessimism

Pessimism word cloud

Many patients with neuropsychiatric disorders such as anxiety or depression experience negative moods that lead them to focus on the possible downside of a given situation more than the potential benefit.

MIT neuroscientists have now pinpointed a brain region that can generate this type of pessimistic mood. In tests in animals, they showed that stimulating this region, known as the caudate nucleus, induced animals to make more negative decisions: They gave far more weight to the anticipated drawback of a situation than its benefit, compared to when the region was not stimulated. This pessimistic decision-making could continue through the day after the original stimulation.

The findings could help scientists better understand how some of the crippling effects of depression and anxiety arise, and guide them in developing new treatments.

"We feel we were seeing a proxy for anxiety, or depression, or some mix of the two," says Ann Graybiel, an MIT Institute Professor, a member of MIT's McGovern Institute for Brain Research, and the senior author of the study, which appears in the Aug. 9 issue of Neuron. "These psychiatric problems are still so very difficult to treat for many individuals suffering from them."

The paper's lead authors are McGovern Institute research affiliates Ken-ichi Amemori and Satoko Amemori, who perfected the tasks and have been studying emotion and how it is controlled by the brain. McGovern Institute researcher Daniel Gibson, an expert in data analysis, is also an author of the paper.

Emotional decisions

Graybiel's laboratory has previously identified a neural circuit that underlies a specific kind of decision-making known as approach-avoidance conflict. These types of decisions, which require weighing options with both positive and negative elements, tend to provoke a great deal of anxiety. Her lab has also shown that chronic stress dramatically affects this kind of decision-making: More stress usually leads animals to choose high-risk, high-payoff options.

In the new study, the researchers wanted to see if they could reproduce an effect that is often seen in people with depression, anxiety, or obsessive-compulsive disorder. These patients tend to engage in ritualistic behaviors designed to combat negative thoughts, and to place more weight on the potential negative outcome of a given situation. This kind of negative thinking, the researchers suspected, could influence approach-avoidance decision-making.

To test this hypothesis, the researchers stimulated the caudate nucleus, a brain region linked to emotional decision-making, with a small electrical current as animals were offered a reward (juice) paired with an unpleasant stimulus (a puff of air to the face). In each trial, the ratio of reward to aversive stimuli was different, and the animals could choose whether to accept or not.

This kind of decision-making requires cost-benefit analysis. If the reward is high enough to balance out the puff of air, the animals will choose to accept it, but when that ratio is too low, they reject it. When the researchers stimulated the caudate nucleus, the cost-benefit calculation became skewed, and the animals began to avoid combinations that they previously would have accepted. This continued even after the stimulation ended, and could also be seen the following day, after which point it gradually disappeared.

This result suggests that the animals began to devalue the reward that they previously wanted, and focused more on the cost of the aversive stimulus. "This state we've mimicked has an overestimation of cost relative to benefit," Graybiel says.

A delicate balance

The researchers also found that brainwave activity in the caudate nucleus was altered when decision-making patterns changed. This change, discovered by Amemori, is in the beta frequency and might serve as a biomarker to monitor whether animals or patients respond to drug treatment, Graybiel says.

Graybiel is now working with psychiatrists at McLean Hospital to study patients who suffer from depression and anxiety, to see if their brains show abnormal activity in the neocortex and caudate nucleus during approach-avoidance decision-making. Magnetic resonance imaging (MRI) studies have shown abnormal activity in two regions of the medial prefrontal cortex that connect with the caudate nucleus.

The caudate nucleus has within it regions that are connected with the limbic system, which regulates mood, and it sends input to motor areas of the brain as well as dopamine-producing regions. Graybiel and Amemori believe that the abnormal activity seen in the caudate nucleus in this study could be somehow disrupting dopamine activity.

"There must be many circuits involved," she says. "But apparently we are so delicately balanced that just throwing the system off a little bit can rapidly change behavior."

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Evolutionary changes in the human brain may have led to bipolar disorder and schizophrenia

The same aspects of relatively recent evolutionary changes that make us prone to bad backs and impacted third molars may have generated long, noncoding stretches of DNA that predispose individuals to schizophrenia, bipolar disorder, and other neuropsychiatric diseases.

A study publishing August 9 in the American Journal of Human Genetics identifies an unusually lengthy array of tandem repeats found only within the human version of a gene governing calcium transport in the brain.

"Changes in the structure and sequence of these nucleotide arrays likely contributed to changes in CACNA1C function during human evolution and may modulate neuropsychiatric disease risk in modern human populations," says senior author David Kingsley, professor of developmental biology at Stanford University.

Common ailments such as lower back, knee, and foot problems are likely due to the transition to walking upright; impacted wisdom teeth may be tied to humans' smaller jaws and recent changes in diet. Kingsley hypothesizes that the prevalence of neurological diseases in modern humans may stem from recent evolutionary changes in genes controlling brain size, connectivity, and function.

Bipolar disorder and schizophrenia affect more than 3 percent of the population worldwide.

Missing data

Tandem repeats are repeated lengths of DNA occurring either inside or outside a gene's coding sequence. They have been hypothesized to explain individual-to-individual variations in complex neurological functions and may act as "tuning knobs" for modulating gene expression. The tandem repeats may affect CACNA1C function -- even when the coding region of the gene itself is free of mutations.

Most genetic studies focus on how simple letter substitutions in the DNA code cause disease. Yet 15 years after the human genome was mapped, regions of the human genome are still largely unexplored, missing, or understudied, Kingsley says. In particular, large regions of repeated sequence can be difficult to propagate in bacteria and to assemble correctly. Many of these regions also vary substantially between individuals and may contribute to key phenotypic traits and disease susceptibilities in humans and other organisms.

After identifying a large discrepancy between the standard human reference genome and levels of DNA sequence reads coming from a key calcium channel gene previously linked to psychiatric disease, Kingsley and Stanford colleagues Janet Song and Craig Lowe carried out further studies of 181 human cell lines and postmortem brain tissue samples. They found lengthy stretches of DNA -- ten to a hundred times longer and more complex than expected -- containing many variant nucleotide base pairs embedded in a noncoding region of the CACNA1C gene.

Different versions of the highly repeated sequences showed different abilities to activate gene expression and were tightly linked to genetic markers of bipolar disease and schizophrenia disease susceptibility in humans. Such "hidden variants" may illuminate the risk of psychiatric disease among patients whose DNA profile is otherwise unremarkable, he says.

Kingsley, a Howard Hughes Medical Institute investigator, says classifying patients based on their repeat arrays may help identify those most likely to respond to existing calcium channel drugs. These medications have produced mixed results to date, he notes, and further study is needed to clarify whether patients with a genetic variation of CACNA1C have too much or too little calcium channel activity. "We hope genotype-based drug targeting will lead to improved future treatments," he says.

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Tbx6 revealed as crucial to heart and skeleton formation from stem cells

Many studies have attempted to identify a single transcription factor that can induce formation of mesoderm, an early layer in embryonic development, without help from other cellular proteins; none have been successful, until now.

In a new study published in Cell Stem Cell, "Tbx6 Induces Nascent Mesoderm from Pluripotent Stem Cells and Temporally Controls Cardiac versus Somite Lineage Diversification," a research team, including experts from the University of Tsukuba, screened over 50 transcription factors and found that Tbx6 alone was able to stimulate mesoderm formation in laboratory-grown stem cells, and could cause those stem cells to become cardiovascular or musculoskeletal cells.

Pluripotent stem cells provide an important window into the mechanisms of cell differentiation, a critical process during development and maintenance of tissues in humans and other animals, and are vital to the framework of regenerative medicine. Despite recent successes in understanding and guiding stem cell differentiation, the overall molecular system required for the induction of mesoderm and its subsequent specialization into tissue-specific cell types has remained elusive because its processes are dynamic and previous studies have been too small to provide conclusive data.

"Tbx6 was already known to be active in formation of musculoskeletal tissue -- Tbx6 mutant mice produce ectopic neural tubes at the expense of musculoskeletal tissue -- but its expression and function in early/nascent mesoderm and mesodermal derivatives, including cardiovascular lineages, have been largely unknown," says Masaki Ieda, corresponding author on the study. "We were surprised to learn that Tbx6 has a broader role in the formation of mesoderm from pluripotent stem cells."

In the study, temporary production of Tbx6 caused the formation of mesoderm that later produced cardiovascular cells, while continuous Tbx6 expression suppressed this cardiovascular-forming mesoderm and caused formation of mesoderm that later produced musculoskeletal cells.

"Our analyses revealed a connection between early Tbx6 expression and cardiovascular lineage differentiation, and we believe that our study and similar studies may change the current view of lineage specification during development," Dr. Ieda explains. "Importantly, this essential and unappreciated function of Tbx6 in mesoderm and cardiovascular specification is conserved from lower organisms to mammals, so this discovery may have wide-ranging applicability in regenerative medicine."

In addition to the broader role of Tbx6, the researchers have shown the usefulness of a new direct reprogramming-based approach to screen for important transcription factors that may regulate cell differentiation.

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Study illuminates genes behind beautiful 'glow' of Bermuda fireworms

This photo is of the Bermuda fireworm Odontosyllis enopla.

A new study led by researchers at the American Museum of Natural History looks at the genes behind an incredible, luminous seasonal mating display produced by swarms of bioluminescent marine Bermuda fireworms. The new research, published today in the journal PLOS ONE, confirms that the enzymes responsible for the fireworms' glow are unique among bioluminescent animals and entirely unlike those seen in fireflies. The study also examines genes associated with some of the dramatic -- and reversible -- changes that happen to the fireworms during reproduction.

The beautiful bioluminescence of the Bermuda fireworm (Odontosyllis enopla), which lives throughout the Caribbean, was first documented in 1492 by Christopher Columbus and his crew just before landing in the Americas. The observations described the lights as "looking like the flame of a small candle alternately raised and lowered."

The phenomenon went unexplained until the 1930s, when scientists matched the historic description with the unusual and precisely timed mating behavior of fireworms. During summer and autumn, beginning at 22 minutes after sunset on the third night after the full Moon, spawning female fireworms secrete a bright bluish-green luminescence that attracts males. "It's like they have pocket watches," said lead author Mercer R. Brugler, a Museum research associate and assistant professor at New York City College of Technology (City Tech).

"The female worms come up from the bottom and swim quickly in tight little circles as they glow, which looks like a field of little cerulean stars across the surface of jet black water," said Mark Siddall, a curator in the American Museum of Natural History's Division of Invertebrate Zoology and corresponding author of the study. "Then the males, homing in on the light of the females, come streaking up from the bottom like comets -- they luminesce, too. There's a little explosion of light as both dump their gametes in the water. It is by far the most beautiful biological display I have ever witnessed."

To further investigate this phenomenon, Siddall, together with Brugler; Michael Tessler, a postdoctoral fellow in the Museum's Sackler Institute for Comparative Genomics, and M. Teresa Aguado, former postdoctoral fellow in the Museum's Sackler Institute for Comparative Genomics who is now at the Autonomous University of Madrid, analyzed the transcriptome -- the full set of RNA molecules -- of a dozen female fireworms from Ferry Reach in Bermuda.

Their findings support previous work showing that fireworms "glow" because of a special luciferase enzyme they produce. These enzymes are the principal drivers of bioluminescence across the tree of life, in organisms as diverse as copepods, fungi, and jellyfish. However, the luciferases found in Bermuda fireworms and their relatives are distinct from those found in any other organism to date.

"It's particularly exciting to find a new luciferase because if you can get things to light up under particular circumstances, that can be really useful for tagging molecules for biomedical research," said Tessler.

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Prehistoric peopling in southeast Asia: Genomics of Jomon and other ancient skeletons

Model for migration routes into Southeast Asia uncovered by genomic data of prehistoric skeletons.

Uncovering the expansion processes of human habitats in the past is of great importance for understanding the origins and establishment of present-day populations and the acquisition of genetic characteristics of individuals as well as for investigating mechanisms of resistance against diseases and pathogens. Previous genetic/genomic studies aimed to uncover the expansion processes using present-day human genomes of different individuals and locations. However, it is not always possible to elucidate the expansion processes based on the genomic similarity of present-day populations due to the possibility of migrations of populations between regions in various periods. It is therefore impossible to uncover the precise expansion processes of populations in the past without knowledge of the genomic information existing in a designated region and period. Thus, expansion processes hypothesized so far were nothing but speculations based on assumptions about present-day genomes.

Recent developments of DNA analysis technology have made it possible to obtain whole genome information from ultratrace amounts of DNA; we are now in an era where whole genome information can be obtained directly from ancient human skeletons discovered at archaeological sites. There remain, however, technical problems for obtaining whole genome information of ancient human skeletons. In particular, there are two main problems: first, genomic analyses of poorly-preserved ancient remains in hot and humid regions of the world have up until now failed. Secondly, there is the risk of contamination of present-day human DNA in the DNA samples of ultratrace amounts from prehistoric remains. To evaluate objectively the possibility of such contamination, several different research groups must cross-check one another in order to achieve exact genome sequencing; in other words, establishment of a collaborative research system is a prerequisite for attaining the highest level of scientific authenticity.

In order to cope with these problems, the present international research team, led by researchers from the University of Copenhagen with the participation of three researchers from Kanazawa University has established technologies to efficiently extract human DNA from skeletons discovered at prehistoric remains even under very poor conditions for DNA preservation. At the same time, an international system of research collaboration has been established for objectively evaluating the effects of contamination by present-day human DNA. Thanks to these efforts, the team has uncovered the expansion processes of human habitats and genetic interactions in hot and wet Southeast Asia, which was not possible previously with conventional technologies and research systems.

Worthy of special mention, the present study has been successful in determining the "whole genome" sequence of an individual with typical Jomon culture, while previous studies were only able to show a very limited "partial genome" sequence of two Jomon individuals. Thus, the present study is the first successful example to show the possibility of whole genome sequencing of prehistoric individuals in regions like Japan where preservation conditions are quite poor, possibly leading to further major progress in prehistoric genome studies.

In the present study, the international research team succeeded in extracting and sequencing DNA from 25 ancient individuals' skeletons from Southeast Asian remains, where the condition of DNA preservation is very poor, and from one Japanese Jomon female skeleton. Upon comparison of the genomic data of ancient human skeletons with those of present-day human skeletons, it has become clear that those prehistoric populations in Southeast Asia can be classified into six groups.

Group 1 contains Hoabinhians from Pha Faen, Laos, hunter-gatherers (~8000 years ago), and prehistoric populations discovered from Gua Cha, Malaysia (~4000 years ago), being genetically close to present-day Önge and Jarawa from the Andaman Islands and Jehai from the Peninsular Malaysia. To our surprise, group 1 has higher genetic affinities with Ikawazu Jomon individual (Tahara, Aichi), a female adult*4), than other present-day Southeast Asians. In addition, the Ikawazu Jomon genome*5) is best modelled contributing genetically present-day Japanese.

On the other hand, Groups 2-6 consist of ancient skeletons from the Neolithic Age, when farming started, until ~500 years ago. It is now found that they are genetically much different from Hoabinhians, each group having histories of migration and genetic interaction, i.e., inter-population mixture. Group 2 is found to be genetically close to the present-day Austroasiatic language-speaking groups such as Mlabri, but to have few genetic components common with the present-day East Asian populations. Group 3 is found to be genetically close to Kradai, Thailand, in the present-day Southeast Asian populations and to the Austronesian language-speaking groups. Group 4 is found to be genetically close to the present-day populations in South China. Group 5 is genetically close to the present-day populations in the western part of Indonesia. Group 6 is most closely related to present day Austronesian populations, with one individual showing slightly elevated Denisovan ancestry, an archaic hominin which is classified as a sister group of Neanderthals.

As above, Neolithic Southeast Asians are found to have been partially genetically influenced by ethnic groups in South China and to have had a genetic connection with populations in Taiwan; Neolithic Southeast Asians are found not to have been indigenous hunter-gatherers passively accepting farming but to have accepted farming gradually in the process of migrations of populations between the continent and islands. Conventional archaeology proposed the two-layer hypothesis that, in those periods, a large population with farming culture with rice and millet migrated into Southeast Asia and that they replaced the indigenous population. Additionally, the present study indicates that the genetic influence from South China with rice farming was only partial and that the migrating population did not replace the indigenous population completely. The present analysis shows that there were at least four big migration waves; migrations of Southeast Asians should be investigated with a new "complex model" framework.

The present study successfully elucidates for the first time the expansion/migration of prehistoric populations by genome analysis of skeletons discovered in Southeast Asia; conventionally, it was thought that such population expansion/migration could only be investigated using archaeological artifacts. An important outcome of the present study is that the same or analogous analyses could be applied to various regions to evaluate the history of population expansion/migration in much more detail and in a more scientific manner.

The genomic data obtained from ancient skeletons in Southeast Asia and from a Ikawazu Jomon individual provides an important basis for investigations on the origins of populations in wider East Asia. The whole genome information of a Jomon individual will be useful for direct comparison of genomic similarity with ancient East Asians of the corresponding period to Jomon in present-day Korea, China, Russia and others in the vicinity of the Japanese archipelago. More comparative studies are in progress on populations in wider areas. Note that the whole genome sequence obtained in this study for a Jomon individual corresponds to the Draft Genome Sequence in the Human Genome Project for the present-day humans. We aim at Complete Genome Sequence with higher accuracy.

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Mojave Desert birds crashed over the last century due to climate change

Joshua Tree National Park

Bird communities in the Mojave Desert straddling the California/Nevada border have collapsed over the past 100 years, most likely because of lower rainfall due to climate change, according to a new University of California, Berkeley, study.

A three-year survey of the area, which is larger than the state of New York, concludes that 30 percent, or 39 of the 135 bird species that were there 100 years ago, are less common and less widespread today. The 61 sites surveyed lost, on average, 43 percent of the species that were there a century ago.

"Deserts are harsh environments, and while some species might have adaptations that allow them to persist in a desert spot, they are also at their physiological limits," said Kelly Iknayan, who conducted the survey for her doctoral thesis at UC Berkeley. "California deserts have already experienced quite a bit of drying and warming because of climate change, and this might be enough to push birds over the edge. It seems like we are losing part of the desert ecosystem."

The collapse could have an impact on desert plants that rely upon birds to spread their seeds and for pollination, she said, as well as on a host of creatures that prey on the birds.

Though the decline has happened across the entire Mojave Desert, sites with available water saw less decline, suggesting that dehydration is a major factor. To halt further losses, the authors suggest, it may be necessary in the short-term to create additional water resources and limit groundwater pumping, which depletes desert springs. The best long-term solution is to reduce greenhouse gas emissions and reverse climate change, the authors say.

The loss of bird species has happened even though much of the Mojave Desert is protected national park or preserve, including Death Valley National Park, one of the nation's largest.

"This is a shot across the bow of our nation's national jewels, telling us that climate change is already having an adverse impact even in our largest national parks and wilderness areas, and that we have got to reduce dependence on fossil fuels by smartly employing green energy," said Steven Beissinger, senior author of the study and a UC Berkeley professor of environmental science, policy and management.

Iknayan and Beissinger will report their findings this week in the journal Proceedings of the National Academy of Sciences.

Raptors are down, ravens are up

The UC Berkeley team found a 42 percent drop in the number of bird species at Mojave sites. Raptors, with their meat-based diet, were one of the groups of birds that declined the most, including the American kestrel, prairie falcon, turkey vulture and sharp-shinned hawk -- all fairly common in the early 20th century.

Rarer birds, such as the Virginia's warbler, red crossbill, mountain quail and Lawrence's goldfinch, are now even rarer.

Birds that are more adapted to the desert -- the roadrunner and cactus wren, for example -- and birds that can live in a variety of habitats, such as the Bewick's wren and California towhee, fared better. Those adapted to grassland or forest did worse.

"A lot of these birds aren't exclusively limited to the desert," Iknayan said, noting declines in relatively widespread mockingbirds, killdeer and various sparrows and flycatchers. "Protecting their populations across the whole range can help a lot of these species to persist into the future."

The only birds more common today in the Mojave are the common raven and four exotics: the great-tailed grackle, which migrated northward from the U.S. Southwest and Mexico; an imported gamebird called the chukar; and the purposely introduced Eurasian collared dove and European starling.

Beissinger refers to the widespread decline as a collapse because it has occurred across the whole desert bird community, unlike changes in bird communities elsewhere, which consist of some declining and some increasing species. The 42 percent decrease in species richness across the Mojave contrasts markedly with a 2 percent decline in richness at sites in the Sierra Nevada revealed by similar surveys.

Breeding bird surveys conducted by citizen scientists dating back to the 1970s confirm the drop in abundance in the Mojave, "which is why we think we are seeing a new, lower baseline" for desert bird populations, he said.

"Studies elsewhere have found that climate change typically makes places unfavorable for some birds but opens the door for others to come in," Iknayan said. "In the desert we are not seeing increases in any of our species except for the common raven. There are a lack of climate change winners in the system."

Taking good notes

Beissinger leads the Grinnell Resurvey Project to survey again areas of California that UC Berkeley biologists surveyed nearly 100 years ago, starting in 1908 with the arrival of Joseph Grinnell to head the campus's Museum of Vertebrate Zoology. The goal of the project is to understand the changes wrought by human occupation of the state, including the impact of global warming and climate change.

Thanks to Grinnell, who introduced a now-widely used method of recording field notes, today's scientists have detailed data about bird and mammal populations and occurrence throughout the state, ranging from the Sierra Nevada and Cascade ranges to the Coast Ranges and Central Valley, and encompassing Southern California and, most recently, the deserts of the state's southeast. Grinnell and his students conducted and dutifully recorded their observations between 1908 and after his death in 1940.

Iknayan and her colleagues visited the 61 Mojave sites, including 9 in Nevada, that Grinnell and his colleagues visited between 1908 and 1947. She spent three consecutive days at each site walking a path as close to Grinnell's as possible, stopping at 10 places along each path and recording all the birds she saw or heard within 7 minutes.

She and Beissinger then conducted a statistical analysis to take account of the fact neither Grinnell nor Iknayan detected all the birds living at a site. The result was a chart of "occupancy" for each of the 135 birds, representing the proportion of surveyed sites the birds actually inhabited, even if undetected, in the early 1900s and now.

They subsequently correlated occupancy with other data for the sites, such as long-term change in average annual temperature, average maximum temperature and average yearly rainfall as well as similar measures for recent years. They also looked at the history of fire, grazing and other habitat changes.

The upshot was that the most significant change associated with bird declines was a long-term decrease in precipitation. Sites that had reduced rainfall suffered more loss of species than sites that remained wetter. The long-term change in maximum temperature at a site was unrelated to species loss.

Read more at Science Daily

Those fragrances you enjoy? Dinosaurs liked them first

Glandular laurel in amber.

The compounds behind the perfumes and colognes you enjoy have been eliciting olfactory excitement since dinosaurs walked the Earth amid the first appearance of flowering plants, new research reveals.

Oregon State University entomologist George Poinar Jr. and his son Greg, a fragrance collector, found evidence that floral scents originated in primitive flowers as far back as 100 million years ago as pollinator attractants -- a role they still play even though today's flowers also have colorful petals for luring pollinators.

"I bet some of the dinosaurs could have detected the scents of these early flowers," George Poinar said. "In fact, floral essences from these early flowers could even have attracted these giant reptiles."

The Poinars examined amber flowers from Burma, including the now extinct glandular laurel flower (Cascolaurus burmensis) and veined star flower (Tropidogyne pentaptera).

The research revealed that the flower-based chemical compounds that are the basis for the perfumes and colognes we use today have been providing olfactory excitement to pollinating insects and other animals since the mid-Cretaceous Period.

Without colorful petals, flowers from that period had to rely solely on scents to attract pollinators.

"You can't detect scents or analyze the chemical components of fossil flowers, but you can find the tissues responsible for the scents," said George Poinar, professor emeritus in the OSU College of Science.

The floral secretory tissues producing these scents include nectaries, glandular trichomes, eliaphores and osmophores.

Nectaries are glands that produce fragrances and sweet deposits that insects love. Glandular trichomes are hairs with cells that make and send out scented secretory products. Eliaphores are stalked aromatic oil glands. oOsmophores, also known as floral fragrance glands, are cell clusters specializing in scent emission.

The study also found that secretory tissues of these Cretaceous flowers are similar in structure to those of their modern descendants. That suggests modern and ancient flowers of the same lineages produced similar essences.

Some of flowers studied were even in the process of emitting compounds at the time they were engulfed by the tree resin that later became amber.

The study also included a milkweed flower (Discoflorus neotropicus) and an acacia flower (Senegalia eocaribbeansis) in 20- to 30-million-year-old Dominican Republic amber.

The anther glands on the fossil acacia flower were especially attractive to bees, one of which was fossilized while visiting the stamens. Today, honeybees are still visiting acacia flowers that have the same type of flora glands that existed in the ancient past.

Read more at Science Daily

Lost Norse of Greenland fueled the medieval ivory trade, ancient walrus DNA suggests

This is an example of an elaborately-carved ecclesiastical walrus ivory plaque from the beginning of the medieval walrus ivory trade, featuring the figure of Christ, together with St Mary and St Peter, and believed to date from the 10th or 11th century. Found in North Elmham, Norfolk, UK, in the 19th century, and currently exhibited in the University of Cambridge's Museum of Archaeology and Anthropology.

The Icelandic Sagas tell of Erik the Red: exiled for murder in the late 10th century he fled to southwest Greenland, establishing its first Norse settlement.

The colony took root, and by the mid-12th century there were two major settlements with a population of thousands. Greenland even gained its own bishop.

By the end of the 15th century, however, the Norse of Greenland had vanished -- leaving only abandoned ruins and an enduring mystery.

Past theories as to why these communities collapsed include a change in climate and a hubristic adherence to failing farming techniques.

Some have suggested that trading commodities -- most notably walrus tusks -- with Europe may have been vital to sustaining the Greenlanders. Ornate items including crucifixes and chess pieces were fashioned from walrus ivory by craftsmen of the age. However, the source of this ivory has never been empirically established.

Now, researchers from the universities of Cambridge and Oslo have studied ancient DNA from offcuts of tusks and skulls, most found on the sites of former ivory workshops across Europe, in order to trace the origin of the animals used in the medieval trade.

In doing so they have discovered an evolutionary split in the walrus, and revealed that the Greenland colonies may have had a "near monopoly" on the supply of ivory to Western Europe for over two hundred years.

For the latest study, published today in the journal Proceedings of the Royal Society B, the research team analysed walrus samples found in several medieval trading centres -- Trondheim, Bergen, Oslo, Dublin, London, Schleswig and Sigtuna -- mostly dating between 900 and 1400 CE.

The DNA showed that, during the last Ice Age, the Atlantic walrus divided into two ancestral lines, which researchers term "eastern" and "western." Walruses of the eastern lineage are widespread across much of the Arctic, including Scandinavia. Those of the western, however, are unique to the waters between western Greenland and Canada.

Finds from the early years of the ivory trade were mostly from the eastern lineage. Yet as demand grew from the 12th century onwards, the research team discovered that Europe's ivory supply shifted almost exclusively to tusks from the western lineage.

They say that ivory from western linage walruses must have been supplied by the Norse Greenlanders -- by hunting and perhaps also by trade with the indigenous peoples of Arctic North America.

"The results suggest that by the 1100s Greenland had become the main supplier of walrus ivory to Western Europe -- a near monopoly even," said Dr James H. Barrett, study co-author from the University of Cambridge's Department of Archaeology.

"The change in the ivory trade coincides with the flourishing of the Norse settlements on Greenland. The populations grew and elaborate churches were constructed.

"Later Icelandic accounts suggest that in the 1120s, Greenlanders used walrus ivory to secure the right to their own bishopric from the king of Norway. Tusks were also used to pay tithes to the church," said Barrett.

He points out that the 11th to 13th centuries were a time of demographic and economic boom in Europe, with growing demand from urban centres and the elite served by transporting commodities from increasingly distant sources.

"The demands for luxury goods produced from ivory may have helped the far-flung Norse communities in Greenland survive for centuries," said Barrett.

Co-author Dr Sanne Boessenkool of the University of Oslo said: "We knew from the start that analysing ancient DNA would have the potential for new historical insights, but the findings proved to be particularly spectacular."

The new study tells us less about the end of the Greenland colonies, say Barrett and colleagues. However, they note that it is hard to find evidence of walrus ivory imports to Europe that date after 1400.

Elephant ivory eventually became the material of choice for Europe's artisans. "Changing tastes could have led to a decline in the walrus ivory market of the Middle Ages," said Barrett.

Ivory exports from Greenland could have stalled for other reasons: over-hunting can cause walrus populations to abandon their coastal "haulouts"; the "Little Ice Age" -- a sustained period of lower temperatures -- began in the 14th century; the Black Death ravaged Europe.

Whatever caused the cessation of Europe's trade in walrus ivory, it must have been significant for the end of the Norse Greenlanders," said Barrett. "An overreliance on a single commodity, the very thing which gave the society its initial resilience, may have also contained the seeds of its vulnerability."

The heyday of the walrus ivory trade saw the material used for exquisitely carved items during Europe's Romanesque art period. The church produced much of this, with major ivory workshops in ecclesiastical centres such as Canterbury, UK.

Ivory games were also popular. The Viking board game hnefatafl was often played with walrus ivory pieces, as was chess, with the famous Lewis chessmen among the most stunning examples of Norse carved ivory.

Tusks were exported still attached to the walrus skull and snout, which formed a neat protective package that was broken up at workshops for ivory removal. These remains allowed the study to take place, as DNA extraction from carved artefacts would be far too damaging.

Co-author Dr Bastiaan Star of the University of Oslo said: "Until now, there was no quantitative data to support the story about walrus ivory from Greenland. Walruses could have been hunted in the north of Russia, and perhaps even in Arctic Norway at that time. Our research now proves beyond doubt that much of the ivory traded to Europe during the Middle Ages really did come from Greenland."

Read more at Science Dialy

Elliptical elegance in glittering host of galaxies

This deep image of the area of sky around the elliptical galaxy NGC 5018 offers a spectacular view of its tenuous streams of stars and gas. These delicate features are hallmarks of galactic interactions, and provide vital clues to the structure and dynamics of early-type galaxies.

Whereas ESO's Very Large Telescope (VLT) can observe very faint astronomical objects in great detail, when astronomers want to understand how the huge variety of galaxies come into being they must turn to a different sort of telescope with a much bigger field of view. The VLT Survey Telescope (VST) is such a telescope. It was designed to explore vast swathes of the pristine Chilean night skies, offering astronomers detailed astronomical surveys of the southern hemisphere.

The powerful surveying properties of the VST led an international team of astronomers to conduct the VST Early-type GAlaxy Survey (VEGAS) to examine a collection of elliptical galaxies in the southern hemisphere. Using the sensitive OmegaCAM detector at the heart of the VST, a team led by Marilena Spavone from INAF-Astronomical Observatory of Capodimonte in Naples, Italy, captured images of a wide variety of such galaxies in different environments.

One of these galaxies is NGC 5018, the milky-white galaxy near the centre of this image. It lies in the constellation of Virgo (The Virgin) and may at first resemble nothing but a diffuse blob. But, on closer inspection, a tenuous stream of stars and gas -- a tidal tail -- can be seen stretching outwards from this elliptical galaxy. Delicate galactic features such as tidal tails and stellar streams are hallmarks of galactic interactions, and provide vital clues to the structure and dynamics of galaxies.

As well as the many elliptical (and a few spiral) galaxies in this remarkable 400-megapixel image, a colourful variety of bright foreground stars in our own Milky Way Galaxy also pepper the image. These stellar interlopers, such as the vividly blue HD 114746 near the centre of the image, are not the intended subjects of this astronomical portrait, but happen to lie between the Earth and the distant galaxies under study. Less prominent, but no less fascinating, are the faint tracks left by asteroids in our own Solar System. Just below NGC 5018, the faint streak left by the asteroid 2001 TJ21 (110423) -- captured over several successive observations -- can be seen stretching across the image. Further to the right, another asteroid -- 2000 WU69 (98603) -- left its trace in this spectacular image.

Read more at Science Daily

Novel approach to coherent control of a three-level quantum system

The oscillating cantilever influences the spin of the electrons in the nitrogen-vacancy centers (red arrows). The phase of the oscillator determined in which direction (clockwise or counter-clockwise) the spin rotates.

For the first time, researchers were able to study quantum interference in a three-level quantum system and thereby control the behavior of individual electron spins. To this end, they used a novel nanostructure, in which a quantum system is integrated into a nanoscale mechanical oscillator in form of a diamond cantilever. Nature Physics has published the study that was conducted at the University of Basel and the Swiss Nanoscience Institute.

The electronic spin is a fundamental quantum mechanical property intrinsic to every electron. In the quantum world, the electronic spin describes the direction of rotation of the electron around its axis which can normally occupy two so-called eigenstates commonly denoted as "up" and "down." The quantum properties of such spins offer interesting perspectives for future technologies, for example in the form of extremely precise quantum sensors.

Combining spins with mechanical oscillators

Researchers led by Professor Patrick Maletinsky and PhD candidate Arne Barfuss from the Swiss Nanoscience Institute at the University of Basel report in Nature Physics a new method to control the spins' quantum behavior through a mechanical system.

For their experimental study, they combined such a quantum system with a mechanical oscillator. More specifically, the researchers employed electrons trapped in so-called nitrogen-vacancy centers and embedded these spins in single-crystalline mechanical resonators made from diamond.

These nitrogen-vacancy spins are special, in that they possess not only two, but three eigenstates, which can be described as "up," "down" and "zero." Using the special coupling of a mechanical oscillator to the spin, they showed for the first time a complete quantum control over such a three-level system, in a way not possible before.

Controlling three quantum states

In particular, the oscillator allowed them to address all three possible transitions in the spin and to study how the resulting excitation pathways interfere with each other.

This scenario, known as "closed-contour driving," has never been investigated so far but opens interesting fundamental and practical perspectives. For example, their experiment allowed for a breaking of time-reversal symmetry, which means that the properties of the system look fundamentally different if the direction of time is reversed than without such inversion. In this scenario, the phase of the mechanical oscillator determined whether the spin circled "clockwise" (direction of rotation up, down, zero, up) or "counter-clockwise."

Extending coherence

This abstract concept has practical consequences for the fragile quantum states. Similar to the well-known Schrödinger's cat, spins can be simultaneously in a superposition of two or three of the available eigenstates for a certain period, the so-called quantum coherence time.

If the three eigenstates are coupled to each other using the closed contour driving discovered here, the coherence time can be significantly extended, as the researchers were able to show. Compared to systems where only two of the three possible transitions are driven, coherence increased almost a hundredfold.

Such coherence protection is a key element for future quantum technologies and another main result of this work.

Read more at Science Daily

Iron-silica particles unlock part of the mystery of Earth's oxygenation

Iron-silica particles helped shield cyanobacteria like these, which played a key role in the oxygenation of Earth's atmosphere according to new research from UAlberta.

The oxygenation of Earth's atmosphere was thanks, in part, to iron and silica particles in ancient seawater, according to a new study by geomicrobiologists at the University of Alberta. But these results solve only part of this ancient mystery.

Early organisms called cyanobacteria produced oxygen through oxygenic photosynthesis, resulting in the oxygenation of Earth's atmosphere. But cyanobacteria needed protection from the sun's UV radiation in order to evolve. That's where iron and silica particles in ancient seawater come in, according to Aleksandra Mloszewska, a former PhD student who conducted this research under the supervision of Kurt Konhauser, professor in the Department of Earth and Atmospheric Sciences, and George Owttrim, professor in the Department of Biological Sciences.

The research team characterized the effect of UV stress on cyanobacteria and the degree of radiation through the seawater medium through a combination of microbiological, spectroscopic, geochemical and modelling techniques. Their results show that the presence of high silica and iron concentrations in early sea water allowed for the formation of iron-silica precipitates that remained suspended in the ocean for extended periods of time.

"In effect, the iron-silica particles acted as an ancient 'sunscreen' for the cyanobacteria, protecting them from the lethal effects of direct UV exposure," said Konhauser, the senior author from UAlberta. "This was critical on the early Earth before a sufficiently thick ozone layer was established that could enable marine plankton to spread across the globe, as is the case today."

More missing pieces

But, the researchers explain, the iron-silica rich precipitates tell only part of the story.

"The accumulation of atmospheric oxygen from cyanobacterial facilitated the evolution of oxygen-based respiration and multicellular organisms," says Owttrim. But the reason for the large amount of time that it took for free oxygen to accumulate permanently in the atmosphere after the initial evolution of cyanobacteria remains a mystery.

While iron-silica precipitates would have allowed early cyanobacteria to survive, UV radiation would still have prevented their widespread growth.

"It is likely that early cyanobacteria would not have been as productive as they are today because of the effects of UV stress. Until the accumulation of sufficient cyanobacteria-derived oxygen allowed a more permanent means of protection to develop, such as an ozone layer, UV stress may have played an even more important role in shaping the structure of the earliest ecosystems," explained Mloszewska.

These new findings are helping researchers to understand not only how early cyanobacteria were affected by the high level of radiation on the early Earth but also the environmental dynamics that affected the oxygenation history of our atmosphere.

"These findings could also be used as a case study to help us understand the potential for the emergence of life on other planets that are affected by elevated UV radiation levels, for example Earth-sized rocky planets within the habitable zones of nearby M-dwarf star systems like TRAPPIST-1, Proxima Centauri, LHS 1140 and Ross 128 among others," said Mloszewska.

Read more at Science Daily

Million fold increase in the power of waves near Jupiter's moon Ganymede

Ganymede is both Jupiter's largest moon and the largest moon in the solar system.

Listening to electro-magnetic waves around the Earth, converted to sound, is almost like listening to singing and chirping birds at dawn with a crackling camp fire nearby. This is why such waves are called chorus waves. They cause polar lights but also high-energy 'killer' electrons that can damage spacecraft. In a recent study to be published in Nature Communications, the authors describe extraordinary chorus waves around other planets in our solar system.

The scientists led by Yuri Shprits of GFZ and the University of Potsdam report that the power of chorus waves is a million times more intense near the Jovian moon Ganymede, and 100 times more intense near the moon Europa than the average around these planets. These are the new results from a systematic study on Jupiter's wave environment taken from the Galileo Probe spacecraft.

"It's a really surprising and puzzling observation showing that a moon with a magnetic field can create such a tremendous intensification in the power of waves," says the lead author of the study Professor Yuri Shprits of GFZ/ University of Potsdam and who is also affiliated with UCLA.

Chorus waves are a special type of radio wave occurring at very low frequencies.

Unlike the Earth, Ganymede and Europa orbit inside the giant magnetic field of Jupiter and the authors believe this is one of the key factors powering the waves. Jupiter's magnetic field is the largest in the solar system, and some 20,000 times stronger than the Earth's.

"Chorus waves have been detected in space around the Earth but they are nowhere near as strong as the waves at Jupiter" says Professor Richard Horne of British Antarctic Survey who is a co-author on the study. "Even if small portion of these waves escapes the immediate vicinity of Ganymede, they will be capable of accelerating particles to very high energies and ultimately producing very fast electrons inside Jupiter's magnetic field."

Jupiter's moon Ganymede was first found to have a magnetic field by Professor Margaret Kivelson and her team at the University of California, Los Angeles, and strong plasma waves were first observed near Ganymede by Professor Don Gurnett and his team at the University of Iowa. However, until now it remained unclear if this were just accidental or whether such increases are systematic and significant.

At the Earth, chorus waves play a major role in producing high-energy 'killer' electrons that can damage spacecraft. The new observations raise the question as to whether they can do the same at Jupiter.

Read more at Science Daily

Key aspects of human cell aging reversed by new compounds

Cellular senescence in human cells.

Key aspects of the ageing of human cells can be reversed by new compounds developed at the University of Exeter, research shows.

In a laboratory study of endothelial cells -- which line the inside of blood vessels -- researchers tested compounds designed to target mitochondria (the "power stations" of cells).

In the samples used in the study, the number of senescent cells (older cells that have deteriorated and stopped dividing) was reduced by up to 50%. The Exeter team also identified two splicing factors (a component of cells) that play a key role in when and how endothelial cells become senescent.

The findings raise the possibility of future treatments not only for blood vessels -- which become stiffer as they age, raising the risk of problems including heart attacks and strokes -- but also for other cells.

"As human bodies age, they accumulate old (senescent) cells that do not function as well as younger cells," said Professor Lorna Harries, of the University of Exeter Medical School.

"This is not just an effect of ageing -- it's a reason why we age.

"The compounds developed at Exeter have the potential to tweak the mechanisms by which this ageing of cells happens.

"We used to think age-related diseases like cancer, dementia and diabetes each had a unique cause, but they actually track back to one or two common mechanisms.

"This research focuses on one of these mechanisms, and the findings with our compounds have potentially opened up the way for new therapeutic approaches in the future.

"This may well be the basis for a new generation of anti-degenerative drugs."

Professor Harries said the goal was to help people stay healthier for longer. She added: "This is about health span and quality of life, rather than merely extending lifespan."

In a paper published last year, the team demonstrated a new way to rejuvenate old cells in the laboratory.

However, the new research looked at precisely targeting and rejuvenating mitochondria in old cells.

Each one of our genes is capable of making more than one product, and splicing factors are the genes that make the decision about which of these products are made.

In this new work, using novel chemicals, the researchers were able to very specifically target two splicing factors (SRSF2 or HNRNPD) that play a key role in determining how and why our cells change with advancing age.

"Nearly half of the aged cells we tested showed signs of rejuvenating into young cell models," said Professor Harries.

The researchers tested three different compounds, all developed at the University of Exeter, and found each produced a 40-50% drop in the number of senescent blood vessel cells.

The compounds in question -- AP39, AP123 and RT01 -- have been designed by the Exeter team to selectively deliver minute quantities of the gas hydrogen sulfide to the mitochondria in cells and help the old or damaged cells to generate the 'energy' needed for survival and to reduce senescence.

"Our compounds provide mitochondria in cells with an alternative fuel to help them function properly," said Professor Matt Whiteman, also from the University of Exeter.

"Many disease states can essentially be viewed as accelerated ageing, and keeping mitochondria healthy helps either prevent or, in many cases using animal models, reverse this.

"Our current study shows that splicing factors play a key role in determining how our compounds work."

Read more at Science Daily

Largest haul of extrasolar planets

The 44 confirmed planets and their approximate size class, orbits and surface temperatures.

Forty-four planets in solar systems beyond our own have been unveiled in one go, dwarfing the usual number of confirmations from extrasolar surveys, which is typically a dozen or less. The findings will improve our models of solar systems and may help researchers investigate exoplanet atmospheres. Novel techniques developed to validate the find could hugely accelerate the confirmation of more extrasolar planet candidates.

An international team of astronomers pooled data from U.S. space agency NASA's Kepler and the European Space Agency (ESA)'s Gaia space telescopes, as well as ground-based telescopes in the U.S. Alongside John Livingston, lead author of the study and a graduate student at the University of Tokyo, the team's combined resources led to the confirmed existence of these 44 exoplanets and described various details about them.

A portion of the findings yield some surprising characteristics: "For example, four of the planets orbit their host stars in less than 24 hours," says Livingston. "In other words, a year on each of those planets is shorter than a day here on Earth." These contribute to a small but growing list of "ultrashort-period" planets, so it could turn out they're not as unusual as they might seem.

"It was also gratifying to verify so many small planets," continues Livingston. "Sixteen were in the same size class as Earth, one in particular turning out to be extremely small -- about the size of Venus -- which was a nice affirmation as it's close to the limit of what is possible to detect."

The source observations for this study were made by Kepler, and they would not have happened were it not for a fault in 2013, which prevented accurate control of the space telescope. "Two out of the four control-reaction wheels failed, which meant Kepler couldn't perform its original mission to stare at one specific patch of the sky," explains Professor Motohide Tamura of the University of Tokyo. "This led to its contingent mission, 'K2' -- our observations came from campaign 10 of this mission. We're lucky Kepler continues to function as well as it does."

The planets observed by K2 are known as transiting planets because their orbits bring them in front of their host stars, slightly reducing their brightness. However, other astrophysical phenomena can cause similar signals, so follow-up observations and detailed statistical analyses were performed to confirm the planetary nature of these signals. As part of his doctoral work, Livingston traveled to Kitt Peak observatory in the U.S. state of Arizona to obtain data from a special type of camera, known as a speckle interferometer installed on a large telescope there. These observations, along with follow-up observations from a telescope in the state of Texas, were necessary to characterize the host stars and rule out false positives. The combination of detailed analyses of data from these ground-based telescopes, K2 and Gaia enabled the precise determination of the planets' sizes and temperatures. The team's findings include 27 additional candidates that are likely to be real planets, which will be the subject of future research.

Read more at Science Daily

Earthquakes can be weakened by groundwater

Around 100,000 earthquakes are recorded worldwide every year, but not all are naturally occurring. Some of the weaker ones are triggered by human activity underground -- this is referred to as induced seismicity. Researchers from EPFL's Laboratory of Experimental Rock Mechanics (LEMR) and the Ecole Normale Supérieure in Paris have just completed a study into the role of fluids in the propagation of induced earthquakes in an effort to decipher the underlying mechanisms. Their findings include the extremely counterintuitive discovery that highly pressurized water in the vicinity of an earthquake tends to limit -- rather than increase -- its intensity. These results were published today in Nature Communications.

Induced earthquakes can be the result of activities like mining, gas and oil extraction, toxic waste or CO2 storage, and the construction of tunnels and dam reservoirs. The generation of geothermal energy is another potential source of induced earthquakes -- and the main one in Switzerland. According to the Swiss Seismological Service, a geothermal project near Basel caused a 3.4 magnitude earthquake in 2006, and one in St. Gallen triggered a 3.5 magnitude trembler in 2013.

Geothermal energy is captured by tapping into subterranean heat. Highly pressurized water is pumped into the earth's crust at a depth of between two and four kilometers. The water is then recovered as steam and used to drive an electricity-producing turbine. "Injecting water can affect water-rock equilibria and disrupt nearby faults, thus triggering earthquakes in the area," says Marie Violay, who runs LEMR.

This type of earthquake is a thorn in the side of geothermal proponents, notes Mateo Acosta, a PhD student at LEMR and the study's lead author: "These earthquakes may be low in intensity, but they can cause damage and affect public opinion -- to the point of derailing projects."

Heat absorption

Acosta ran tests in which he sought to replicate earthquake conditions in order to study the impact of different levels of underground water pressure on fault dynamics. He focused mainly on earthquake propagation, which is when the two plates in a fault rub against each other, sending seismic waves out into the surrounding area.

"Rock friction generates a significant amount of heat, which further fuels the propagation effect," says the PhD student. "Some of this heat is absorbed by the water in the surrounding rock, and the amount absorbed depends to a large extent on the water's thermodynamic parameters. What we learned from our experiments is that the closer the fluid's initial pressure is to the critical pressure of water, the weaker the earthquake will be."

"This research shows that the initial fluid pressure in the rocks is crucial, especially at depths commonly reached by geothermal activities. Geothermal models need to take this into account," says François-Xavier Passelègue, an LEMR researcher and the study's second author.

Read more at Science Daily

Novel vaccine approach proves powerful against Zika virus

A uniquely designed experimental vaccine against Zika virus has proven powerful in mice, new research has found.

A team led by researchers at The Ohio State University has developed and tested a vaccine that employs an uncommon two-pronged approach to fighting the virus, which is spread by mosquitos and is most serious for pregnant women and their fetuses.

The single-dose vaccine, carrying the genes for two or three Zika proteins, proved effective in triggering an immune response that prevented later infection by Zika virus, according to the study, which appears in the journal Nature Communications.

"In this study, the vaccine was potent, safe and highly effective, at least in the short term. There's a long way to go, but we think this is a promising candidate for a human vaccine," said Jianrong Li, an Ohio State professor of veterinary biosciences who led the study and developed the vaccine platform.

Babies born to Zika-infected mothers are sometimes born with a birth defect called microcephaly. Other complications include miscarriage, stillbirth and other birth defects. Research also suggests that a small percentage of people infected with the virus can contract Guillain-Barre syndrome, which affects the nervous system.

There's no vaccine available currently -- though some are in clinical trials -- and the only protection against Zika are preventative measures such as insect repellant, staying indoors and wearing long sleeves and pants.

Shan-Lu Liu, a study co-author and director of Ohio State's Viruses and Emerging Pathogens Program, said the experimental vaccine holds particular promise because it appears to afford an adequate immune response with one dose. In hard-to-reach and resource-poor areas, that becomes especially valuable, he said.

When this study began, the Ohio State team wondered if a novel approach to vaccination might prove effective against the virus -- one in which they targeted a protective immune response by expressing two or three Zika proteins.

As a vehicle for the Zika proteins, they looked to vesicular stomatitis virus, or VSV, which is a foot-and-mouth disease in cattle. The weakened form of the virus is harmless in humans and mice. VSV has been used in other vaccines, including a successful Ebola vaccine which has been used in preventing outbreaks in humans in Africa.

"It's a good platform for human vaccines, because people don't have any antibodies against it and that allows VSV to successfully transport the vaccine without being stopped by the immune system," said study co-author Mark Peeples, a pediatrics professor at Ohio State and researcher at Nationwide Children's Hospital in Columbus.

In general, vaccines work by delivering harmless amounts of the target virus proteins to the bloodstream, allowing the body to build up immune responses that will provide protection in the event of subsequent exposure to the virus. Li's work has been focused on weakening VSV so that it doesn't cause any problems and then inserting genes from other viruses to make powerful vaccines, said Peeples, who first encouraged Li to consider applying his vaccine platform to Zika.

In the experimental vaccine, VSV acts as a vehicle to deliver the genes for two or three key proteins from the Zika virus, carrying them into the mouse and expressing them inside some of the cells in the mouse so that the immune system could respond and build up a defense against Zika.

"The addition of NS1 protein is an innovative approach for a vaccine -- it's a protein that is made after the Zika virus infects a cell. It's what this bug uses to replicate itself once it's inside the host," said Prosper Boyaka, a study co-author and Ohio State professor of veterinary biosciences.

The study included experiments in mice with severely compromised immune systems -- a necessary step to make sure that mice could get sick after infection with Zika virus. When the vaccinated mice were exposed to Zika virus, their weak immune systems fought it off swiftly and efficiently, convincing the research team that their design had worked.

Without using the immunocompromised animals, the researchers would not have known how safe and effective the vaccine was, Peeples said.

The early success with this vaccine has encouraged this team to use the same approach to fight other related viruses, including Dengue fever, the researchers said.

The researchers also looked at the response to a vaccine with just the unique NS1 gene inserted into VSV and for the first time established that it offered partial protection all on its own, confirming its value in the vaccine, Boyaka said.

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Oldest-ever igneous meteorite contains clues to planet building blocks

NWA 11119 is an unusual light-green fusion crust, silica mineral-rich achondrite meteorite.

Scientists believe the solar system was formed some 4.6 billion years ago when a cloud of gas and dust collapsed under gravity possibly triggered by cataclysmic explosion from a nearby massive star or supernova. As this cloud collapsed, it formed a spinning disk with the sun in the center.

Since then scientists have been able to establish the formation of the solar system piece by piece. Now, new research has enabled scientists from The University of New Mexico, Arizona State University and NASA's Johnson Space Center to add another piece to that puzzle with the discovery of the oldest-ever dated igneous meteorite.

The research titled, Silica-rich volcanism in the Early Solar System Dated at 4.565 Ga, was published today in Nature Communications. This research provides direct evidence that chemically evolved silica-rich crustal rocks were forming on planetsimals within the first 10 million years prior to the assembly of the terrestrial planets and helps scientists further understand the complexities of planet formation.

"The age of this meteorite is the oldest, igneous meteorite ever recorded," said Professor and Director of the Institute of Meteoritics Carl Agee. "Not only is this just an extremely unusual rock type, it's telling us that not all asteroids look the same. Some of them look almost like the crust of the Earth because they're so light colored and full of SiO2. These not only exist, but it occurred during one of the very first volcanic events to take place in the solar system."

The research started to unfold at UNM when graduate student and lead author Poorna Srinivasan, asked Agee for ideas on her Ph.D. thesis. Agee had a yet-to-be studied crustal rock that was found in a sand dune in Mauritania by a nomad that he received from a meteorite dealer. The rock was lighter in color than most meteorites and was laced with green crystals, cavities and surrounded by quench melt. He gave the sample to Srinivasan who began to study the mineralogy of the rock, Northwest Africa (NWA) 11119.

Using an electron microprobe and a CT (computed tomography) scan at UNM and Johnson Space Center facilities, Srinivasan started to examine the composition and mineralogy of the rock. Srinivasan started to note the intricacies of NWA 11119 and noted the unusual light-green fusion crust, silica mineral-rich achondrite meteorite containing information substantially widening scientific knowledge involving the range of volcanic rock compositions within the first 3.5 million years of solar system creation.

"The mineralogy of this rock is a very, very different from anything that we've worked on before," said Srinivasan. "I examined the mineralogy to understand all of the phases that comprise the meteorite. One of the main things we saw first were the large silica crystals of tridymite which is a similar to the mineral quartz. When we conducted further image analyses to quantify the tridymite, we found that the amount present was a staggering 30 percent of the total meteorite -- this amount is unheard of in meteorites and is only found at these levels in certain volcanic rocks from the Earth."

Part of Srinivasan's research also involved trying to figure out through chemical and isotopic analyses what body the meteorite could be from. Utilizing oxygen isotopes done in collaboration with Dr. Karen Ziegler in UNM's Center for Stable Isotope (CSI) lab, she was able to determine that it was definitely extraterrestrial.

"Based on oxygen isotopes, we know it's from an extraterrestrial source somewhere in the solar system, but we can't actually pinpoint it to a known body that has been viewed with a telescope," said Srinivasan. "However, through the measured isotopic values, we were able to possibly link it to two other unusual meteorites (Northwest Africa 7235 and Almahata Sitta) suggesting that they all are from the same parent body -- perhaps a large, geologically complex body that formed in the early solar system."

One possibility is that this parent body was disrupted through a collision with another asteroid or planetesimal and some of its ejected fragments eventually reached the Earth's orbit, falling through the atmosphere and ending up as meteorites on the ground -- in the case of NWA 11119, falling in Mauritania at a yet unknown time in the past.

"The oxygen isotopes of NWA11119, NWA 7235, and Almahata Sitta are all identical, but this rock -- NWA 11119 -- stands out as something completely different from any of the over 40,000 meteorites that have been found on Earth," said Srinivasan.

Further, research using an inductively coupled plasma mass spectrometry was performed in the Isotope Cosmochemistry and Geochronology Laboratory (ICGL) at the Center for Meteorite Studies at Arizona State University to determine the precise formation age of the meteorite. The research confirmed that NWA 11119 is the oldest-ever igneous meteorite recorded at 4.565 billion years.

"The purpose of this research was to understand the origin and formation time of an unusually silica-rich igneous meteorite," says co-author and ASU's Center for Meteorite Studies director, Meenakshi Wadhwa. "Most other known igneous asteroidal meteorites have 'basaltic' compositions that have much lower abundances of silica -- so we wanted to understand how and when this unique silica-rich meteorite formed in the crust of an asteroidal body in the early Solar System."

Most meteorites are formed through the collision of asteroids orbiting the sun in a region called the asteroid belt. Asteroids are the remains from the formation of the solar system formation some 4.6 billion years ago. The chemical composition ranges of ancient igneous meteorites, or achondrites, are key to understanding the diversity and geochemical evolution of planetary building blocks. Achondrite meteorites record the first episodes of volcanism and crust formation, the majority of which are basaltic.

"The meteorite we studied is unlike any other known meteorite," says co-author and ASU School of Earth and Space Exploration graduate student Daniel Dunlap. "It has the highest abundance of silica and the most ancient age (4.565 billion years old) of any known igneous meteorite. Meteorites like this were the precursors to planet formation and represent a critical step in the evolution of rocky bodies in our solar system."

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First North American co-occurrence of Hadrosaur and Therizinosaur tracks found in Alaska

Artist's rendering of therizinosaurs and hadrosaurs at Alaska's Denali National Park during the Cretaceous Period.

An international team of paleontologists and other geoscientists has discovered the first North American co-occurrence of hadrosaur and therizinosaur tracks in the lower Cantwell Formation within Denali National Park, suggesting that an aspect of the continental ecosystem of central Asia was also present in this part of Alaska during the Late Cretaceous.

This comprehensive cross-disciplinary effort has resulted in a paper -- entitled "An unusual association of hadrosaur and therizinosaur tracks within Late Cretaceous rocks of Denali National Park, Alaska" -- published in Scientific Reports, an online open access scientific mega journal published by the Nature Publishing Group, covering all areas of the natural sciences.

Anthony R. Fiorillo, Ph.D., chief curator and vice president of research and collections at the Perot Museum of Nature and Science in Dallas, Texas, is the lead author. Co-authors are Paul J. McCarthy, Ph.D., University of Alaska, Department of Geosciences; Yoshitsugu Kobayashi, Ph.D., Hokkaido University Museum, Sapporo, Hokkaido, Japan; Carla S. Tomsich, graduate student, University of Alaska, Department of Geosciences; Ronald S. Tykoski, Ph.D., director of paleontology lab, Perot Museum of Nature and Science; Yuong-Nam Lee, Ph.D., School of Earth and Environmental Sciences, Seoul National University, South Korea; Tomonori Tanaka, graduate student, Hokkaido University Museum, Sapporo, Hokkaido, Japan; and Christopher R. Noto, Ph.D., Department of Biological Sciences, University of Wisconsin-Parkside, Kenosha, Wisconsin.

Fiorillo and a colleague published on a distinct single footprint in Denali National Park in 2012 that they determined to be made by a therizinosaur, an unusual predatory dinosaur thought to have become an herbivore. Therizinosaurs are best known from Asia. Upon his return in 2013 and 2014, they conducted a more detailed analysis of the area, and he and his colleagues unearthed dozens more tracks of therizinosaurs. What surprised Fiorillo and his team most was the co-occurrence of dozens of hadrosaurs, also known as duck-bill dinosaurs.

"Hadrosaurs are very common and found all over Denali National Park. Previously, they had not been found alongside therizinosaurs in Denali. In Mongolia, where therizinosaurs are best known -- though no footprints have been found in association -- skeletons of hadrosaurs and therizinosaurs have been found to co-occur from a single rock unit so this was a highly unusual find in Alaska, and it prompted my interest," said Fiorillo. "From our research, we've determined that this track association of therizinosaurs and hadrosaurs is currently the only one of its kind in North America."

The plant-eating therizinosaurs are rare and unusual creatures in the fossil record. The strange-looking dinosaurs had long skinny necks, little teeth, a small beak for cropping plants, and big torsos accompanied by large hind feet and long arms with "hands like Freddy Krueger."

Though therizinosaurs are known from Asia and North America, the best and most diverse fossil record is from Asia -- even up to the time of extinction -- and therein is the connection. Fiorillo has long postulated that

Cretaceous Alaska could have been the thoroughfare for fauna between Western North America and Asia -- two continents that shared each other's fauna and flora in the latest stages of the Cretaceous.

"This study helps support the idea that Alaska was the gateway for dinosaurs as they migrated between Asia and North America," said Dr. Kobayashi.

To support the theory, Fiorillo's international team of scientists from across the U.S., Japan and South Korea worked to establish if the tracks were those of a therizinosaur and to study any unique aspects of the ecosystem. The members -- including a sedimentologist, geologist, paleobotanist, paleoecologist and additional paleontologists including an expert on therizinosaurs -- determined that this particular area of Denali was a wet, marsh-like environment and that one fossil in particular looked like a water lily, which supported the theory that there were ponds and standing water nearby. They suspect that both therizinosaurs and hadrosaurs liked these wetter locations.

Fiorillo believes that this Alaskan discovery may connect these animals environmentally and perhaps behaviorally to other therizinosaurs in central Asia. An Asian report of these animals being associated also came from an interval of rocks that was unusually 'wet' at the time, relative to rocks above and below it.

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