Largest-ever study of pets and kids' health finds no link

While many previous studies have suggested a link between pet ownership and better emotional and physical health, RAND researchers say their analysis has more credibility because it analyzed a larger sample than previous efforts.

Contrary to popular belief, having a dog or cat in the home does not improve the mental or physical health of children, according to a new RAND Corporation study.

The findings are from the largest-ever study to explore the notion that pets can improve children's health by increasing physical activity and improving young people's empathy skills.

Unlike earlier smaller studies on the topic, the RAND work used advanced statistical tools to control for multiple factors that could contribute to a child's wellbeing other than pet ownership, such as belonging to a family that has higher income or living in a more affluent setting. The results are published online by the journal Anthrozoos.

"We could not find evidence that children from families with dogs or cats are better off either in terms of their mental wellbeing or their physical health," said Layla Parast, a co-author of the study and a statistician at RAND, a nonprofit research organization. "Everyone on the research team was surprised -- we all have or grew up with dogs and cats. We had essentially assumed from our own personal experiences that there was a connection."

The study analyzed information from more than 2,200 children who lived in pet-owning households in California and compared them to about 3,000 households without a dog or cat. The information was collected as a part of the 2003 California Health Interview Survey, an annual survey that for one year also asked participants about whether they had pets, along with an array of other health questions.

Researchers did find that children from pet-owning families tended to have better general health, have slightly higher weight and were more likely to be physically active compared to children whose families did not have pets. In addition, children who had pets were more likely to have ADD/ADHD, were more likely to be obedient and were less likely to have parents concerned about their child's feelings, mood, behavior and learning ability.

But when researchers adjusted the findings to account for other variables that might be associated with both the likelihood that a family has a pet and the child's health, the association between pet ownership and better health disappeared. Overall, researchers considered more than 100 variables in adjusting their model of pet ownership and health, including family income, language skills and type of family housing.

While many previous studies have suggested a link between pet ownership and better emotional and physical health, RAND researchers say their analysis has more credibility because it analyzed a larger sample than previous efforts.

Researchers say future research could examine associations involving pet ownership over longer periods of time and in more experimental settings.

Read more at Science Daily

Women have more active brains than men

Side view of the brain summarizing blood flow results from tens of thousands of study subjects shows increased blood flow in women compared to men, highlighted in the red colored areas of the brain: the cingulate gyrus and precuneus. Men in this image have higher blood flow in blue colored areas -- the cerebellum.

In the largest functional brain imaging study to date, the Amen Clinics (Newport Beach, CA) compared 46,034 brain SPECT (single photon emission computed tomography) imaging studies provided by nine clinics, quantifying differences between the brains of men and women. The study is published in the Journal of Alzheimer's Disease.

Lead author, psychiatrist Daniel G. Amen, MD, founder of Amen Clinics, Inc., commented, "This is a very important study to help understand gender-based brain differences. The quantifiable differences we identified between men and women are important for understanding gender-based risk for brain disorders such as Alzheimer's disease. Using functional neuroimaging tools, such as SPECT, are essential to developing precision medicine brain treatments in the future."

The brains of women in the study were significantly more active in many more areas of the brain than men, especially in the prefrontal cortex, involved with focus and impulse control, and the limbic or emotional areas of the brain, involved with mood and anxiety. The visual and coordination centers of the brain were more active in men. SPECT can measure blood perfusion in the brain. Images acquired from subjects at rest or while performing various cognitive tasks will show different blood flow in specific brain regions.

Subjects included 119 healthy volunteers and 26,683 patients with a variety of psychiatric conditions such as brain trauma, bipolar disorders, mood disorders, schizophrenia/psychotic disorders, and attention deficit hyperactivity disorder (ADHD). A total of 128 brain regions were analyzed for subjects at baseline and while performing a concentration task.

Understanding these differences is important because brain disorders affect men and women differently. Women have significantly higher rates of Alzheimer's disease, depression, which is itself is a risk factor for Alzheimer's disease, and anxiety disorders, while men have higher rates of (ADHD), conduct-related problems, and incarceration (by 1,400%).

Editor-in-Chief of the Journal of Alzheimer's Disease and Dean of the College of Sciences at The University of Texas at San Antonio, Dr. George Perry said, "Precisely defining the physiological and structural basis of gender differences in brain function will illuminate Alzheimer's disease and understanding our partners."

Read more at Science Daily

Molecule in human saliva has potential for wound healing

Wounds in your mouth heal faster and more efficiently than wounds elsewhere -- but why?

A study published online in The FASEB Journal delves into the mystifying fact that wounds in your mouth heal faster and more efficiently than wounds elsewhere. Until now, it was understood that saliva played a part in the wound healing process, though the extent of its role was unknown. The study examined the effects of salivary peptide histatin-1 on angiogenesis (blood vessel formation), which is critical to the efficiency of wound healing. Researchers found that histatin-1 promotes angiogenesis, as well as cell adhesion and migration.

"These findings open new alternatives to better understand the biology underlying the differences between oral and skin wound healing," said Vicente A. Torres, Ph.D., associate professor at the Institute for Research in Dental Sciences within the Faculty of Dentistry at the University of Chile in Santiago, Chile. "We believe that the study could help the design of better approaches to improve wound healing in tissues other than the mouth."

The study involved experiments at three levels: (1) endothelial, or blood vessel-forming, cells in culture, (2) chicken embryos as animal models, and (3) saliva samples obtained from healthy donors. Using these three models, histatin-1 and saliva were found to increase blood vessel formation. Researchers are now taking the next step in this line of study -- using these molecules to generate materials and implants to aid in wound healing.

"The clear results of the present study open a wide door to a therapeutic advance. They also bring to mind the possible meaning of animals, and often children, 'licking their wounds,'" said Thoru Pederson, Ph.D., Editor-in-Chief of The FASEB Journal.

From Science Daily

Black holes pervade the universe, celestial census indicates

There are a lot more black holes in the Milky Way than previously thought, according to a new UCI study by (from left) James Bullock, chair and professor of physics & astronomy; Manoj Kaplinghat, professor of physics & astronomy; and Oliver Elbert, physics & and astronomy graduate student.

After conducting a cosmic inventory of sorts to calculate and categorize stellar-remnant black holes, astronomers from the University of California, Irvine have concluded that there are probably tens of millions of the enigmatic, dark objects in the Milky Way -- far more than expected.

"We think we've shown that there are as many as 100 million black holes in our galaxy," said UCI chair and professor of physics & astronomy James Bullock, co-author of a research paper on the subject in the current issue of Monthly Notices of the Royal Astronomical Society.

UCI's celestial census began more than a year and a half ago, shortly after the news that the Laser Interferometer Gravitational-Wave Observatory, or LIGO, had detected ripples in the space-time continuum created by the distant collision of two black holes, each the size of 30 suns.

"Fundamentally, the detection of gravitational waves was a huge deal, as it was a confirmation of a key prediction of Einstein's general theory of relativity," Bullock said. "But then we looked closer at the astrophysics of the actual result, a merger of two 30-solar-mass black holes. That was simply astounding and had us asking, 'How common are black holes of this size, and how often do they merge?'"

He said that scientists assume most stellar-remnant black holes -- which result from the collapse of massive stars at the end of their lives -- will be about the same mass as our sun. To see evidence of two black holes of such epic proportions finally coming together in a cataclysmic collision had some astronomers scratching their heads.

UCI's work was a theoretical investigation into the "weirdness of the LIGO discovery," Bullock said. The research, led by doctoral candidate Oliver Elbert, was an attempt to interpret the gravitational wave detections through the lens of what is known about galaxy formation and to form a framework for understanding future occurrences.

"Based on what we know about star formation in galaxies of different types, we can infer when and how many black holes formed in each galaxy," Elbert said. "Big galaxies are home to older stars, and they host older black holes too."

According to co-author Manoj Kaplinghat, UCI professor of physics & astronomy, the number of black holes of a given mass per galaxy will depend on the size of the galaxy.

The reason is that larger galaxies have many metal-rich stars, and smaller dwarf galaxies are dominated by big stars of low metallicity. Stars that contain a lot of heavier elements, like our sun, shed a lot of that mass over their lives. When it comes time for one to end it all in a supernova, there isn't as much matter left to collapse in on itself, resulting in a lower-mass black hole. Big stars with low metal content don't shed as much of their mass over time, so when one of them dies, almost all of its mass will wind up in the black hole.

"We have a pretty good understanding of the overall population of stars in the universe and their mass distribution as they're born, so we can tell how many black holes should have formed with 100 solar masses versus 10 solar masses," Bullock said. "We were able to work out how many big black holes should exist, and it ended up being in the millions -- way more than I anticipated."

In addition, to shed light on subsequent phenomena, the UCI researchers sought to determine how often black holes occur in pairs, how often they merge, and how long it takes. They wondered whether the 30-solar-mass black holes detected by LIGO were born billions of years ago and took a long time to merge or came into being more recently (within the past 100 million years) and merged soon after.

"We show that only 0.1 to 1 percent of the black holes formed have to merge to explain what LIGO saw," Kaplinghat said. "Of course, the black holes have to get close enough to merge in a reasonable time, which is an open problem."

Elbert said he expects many more gravitation wave detections so that he and other astronomers can determine if black holes collide mostly in giant galaxies. That, he said, would tell them something important about the physics that drive them to coalesce.

Read more at Science Daily

New look at archaic DNA rewrites human evolution story

These population trees with embedded gene trees show how mutations can generate nucleotide site patterns. The four branch tips of each gene tree represent genetic samples from four populations: modern Africans, modern Eurasians, Neanderthals, and Denisovans. In the left tree, the mutation (shown in blue) is shared by the Eurasian, Neanderthal and Denisovan genomes. In the right tree, the mutation (shown in red) is shared by the Eurasian and Neanderthal genomes.

Hundreds of thousands of years ago, the ancestors of modern humans diverged from an archaic lineage that gave rise to Neanderthals and Denisovans. Yet the evolutionary relationships between these groups remain unclear.

A University of Utah-led team developed a new method for analyzing DNA sequence data to reconstruct the early history of the archaic human populations. They revealed an evolutionary story that contradicts conventional wisdom about modern humans, Neanderthals and Denisovans.

The study found that the Neanderthal-Denisovan lineage nearly went extinct after separating from modern humans. Just 300 generations later, Neanderthals and Denisovans diverged from each other around 744,000 years ago. Then, the global Neanderthal population grew to tens of thousands of individuals living in fragmented, isolated populations scattered across Eurasia.

"This hypothesis is against conventional wisdom, but it makes more sense than the conventional wisdom." said Alan Rogers, professor in the Department of Anthropology and lead author of the study that will publish online on August 7, 2017 in the Proceedings of the National Academy of Sciences.

A different evolutionary story

With only limited samples of fossil fragments, anthropologists assemble the history of human evolution using genetics and statistics.

Previous estimates of the Neanderthal population size are very small -- around 1,000 individuals. However, a 2015 study showed that these estimates underrepresent the number of individuals if the Neanderthal population was subdivided into isolated, regional groups. The Utah team suggests that this explains the discrepancy between previous estimates and their own much larger estimate of Neanderthal population size.

"Looking at the data that shows how related everything was, the model was not predicting the gene patterns that we were seeing," said Ryan Bohlender, post-doctoral fellow at the M. D. Anderson Cancer Center at the University of Texas, and co-author of the study. "We needed a different model and, therefore, a different evolutionary story."

The team developed an improved statistical method, called legofit, that accounts for multiple populations in the gene pool. They estimated the percentage of Neanderthal genes flowing into modern Eurasian populations, the date at which archaic populations diverged from each other, and their population sizes.

A family history in DNA

The human genome has about 3.5 billion nucleotide sites. Over time, genes at certain sites can mutate. If a parent passes down that mutation to their kids, who pass it to their kids, and so on, that mutation acts as a family seal stamped onto the DNA.

Scientists use these mutations to piece together evolutionary history hundreds of thousands of years in the past. By searching for shared gene mutations along the nucleotide sites of various human populations, scientists can estimate when groups diverged, and the sizes of populations contributing to the gene pool.

"You're trying to find a fingerprint of these ancient humans in other populations. It's a small percentage of the genome, but it's there," said Rogers.

They compared the genomes of four human populations: Modern Eurasians, modern Africans, Neanderthals and Denisovans. The modern samples came from Phase I of the 1000-Genomes project and the archaic samples came from the Max Planck Institute for Evolutionary Anthropology. The Utah team analyzed a few million nucleotide sites that shared a gene mutation in two or three human groups, and established 10 distinct nucleotide site patterns.

Against conventional wisdom

The new method confirmed previous estimates that modern Eurasians share about 2 percent of Neanderthal DNA. However, other findings questioned established theories.

Their analysis revealed that 20 percent of nucleotide sites exhibited a mutation only shared by Neanderthals and Denisovans, a genetic timestamp marking the time before the archaic groups diverged. The team calculated that Neanderthals and Denisovans separated about 744,000 years ago, much earlier than any other estimation of the split.

"If Neanderthals and Denisovans had separated later, then there ought to be more sites at which the mutation is present in the two archaic samples, but is absent from modern samples," said Rogers.

The analysis also questioned whether the Neanderthal population had only 1,000 individuals. There is some evidence for this; Neanderthal DNA contains mutations that usually occur in small populations with little genetic diversity.

However, Neanderthal remains found in various locations are genetically different from each other. This supports the study's finding that regional Neanderthals were likely small bands of individuals, which explains the harmful mutations, while the global population was quite large.

"The idea is that there are these small, geographically isolated populations, like islands, that sometimes interact, but it's a pain to move from island to island. So, they tend to stay with their own populations," said Bohlender.

Their analysis revealed that the Neanderthals grew to tens of thousands of individuals living in fragmented, isolated populations.

"There's a rich Neanderthal fossil record. There are lots of Neanderthal sites," said Rogers. "It's hard to imagine that there would be so many of them if there were only 1,000 individuals in the whole world."

Read more at Science Daily

DNA from Viking cod bones suggests 1,000-year history of European fish trade

One of the ancient Viking cod bones from Haithabu used in the study.

Norway is famed for its cod. Catches from the Arctic stock that spawns each year off its northern coast are exported across Europe for staple dishes from British fish and chips to Spanish bacalao stew.

Now, a new study published today in the journal PNAS suggests that some form of this pan-European trade in Norwegian cod may have been taking place for 1,000 years.

Latest research from the universities of Cambridge and Oslo, and the Centre for Baltic and Scandinavian Archaeology in Schleswig, used ancient DNA extracted from the remnants of Viking-age fish suppers.

The study analysed five cod bones dating from between 800 and 1066 AD found in the mud of the former wharves of Haithabu, an early medieval trading port on the Baltic. Haithabu is now a heritage site in modern Germany, but at the time was ruled by the King of the Danes.

The DNA from these cod bones contained genetic signatures seen in the Arctic stock that swims off the coast of Lofoten: the northern archipelago still a centre for Norway's fishing industry.

Researchers say the findings show that supplies of 'stockfish' -- an ancient dried cod dish popular to this day -- were transported over a thousand miles from northern Norway to the Baltic Sea during the Viking era.

Prior to the latest study, there was no archaeological or historical proof of a European stockfish trade before the 12th century.

While future work will look at further fish remains, the small size of the current study prevents researchers from determining whether the cod was transported for trade or simply used as sustenance for the voyage from Norway.

However, they say that the Haithabu bones provide the earliest evidence of fish caught in northern Norway being consumed on mainland Europe -- suggesting a European fish trade involving significant distances has been in operation for a millennium.

"Traded fish was one of the first commodities to begin to knit the European continent together economically," says Dr James Barrett, senior author of the study from the University of Cambridge's McDonald Institute for Archaeological Research.

"Haithabu was an important trading centre during the early medieval period. A place where north met south, pagan met Christian, and those who used coin met those who used silver by weight."

"By extracting and sequencing DNA from the leftover fish bones of ancient cargoes at Haithabu, we have been able to trace the source of their food right the way back to the cod populations that inhabit the Barents Sea, but come to spawn off Norway's Lofoten coast every winter.

"This Arctic stock of cod is still highly prized -- caught and exported across Europe today. Our findings suggest that distant requirements for this Arctic protein had already begun to influence the economy and ecology of Europe in the Viking age."

Stockfish is white fish preserved by the unique climate of north Norway, where winter temperature hovers around freezing. Cod is traditionally hung out on wooden frames to allow the chill air to dry the fish. Some medieval accounts suggest stockfish was still edible as much as ten years after preservation.

The research team argue that the new findings offer some corroboration to the unique 9th century account of the voyages of Ohthere of Hålogaland: a Viking chieftain whose visit to the court of King Alfred in England resulted in some of his exploits being recorded.

"In the accounts inserted by Alfred's scribes into the translation of an earlier 5th century text, Ohthere describes sailing from Hålogaland to Haithabu," says Barrett. Hålogaland was the northernmost province of Norway.

"While no cargo of dried fish is mentioned, this may be because it was simply too mundane a detail," says Barrett. "The fish-bone DNA evidence is consistent with the Ohthere text, showing that such voyages between northern Norway and mainland Europe were occurring."

"The Viking world was complex and interconnected. This is a world where a chieftain from north Norway may have shared stockfish with Alfred the Great while a late-antique Latin text was being translated in the background. A world where the town dwellers of a cosmopolitan port in a Baltic fjord may have been provisioned from an Arctic sea hundreds of miles away."

The sequencing of the ancient cod genomes was done at the University of Oslo, where researchers are studying the genetic makeup of Atlantic cod in an effort to unpick the anthropogenic impacts on these long-exploited fish populations.

"Fishing, particularly of cod, has been of central importance for the settlement of Norway for thousands of years. By combining fishing in winter with farming in summer, whole areas of northern Norway could be settled in a more reliable manner," says the University of Oslo's Bastiaan Star, first author of the new study.

Star points to the design of Norway's new banknotes that prominently feature an image of cod, along with a Viking ship, as an example of the cultural importance still placed on the fish species in this part of Europe.

Read more at Science Daily

Breakthrough device heals organs with a single touch

Researchers demonstrate a process known as tissue nanotransfection at The Ohio State University Wexner Medical Center. In laboratory tests, this process was able to heal the badly injured legs of mice in just three weeks with a single touch of this chip. The technology works by converting normal skin cells into vascular cells, which helped heal the wounds.

Researchers at The Ohio State University Wexner Medical Center and Ohio State's College of Engineering have developed a new technology, Tissue Nanotransfection (TNT), that can generate any cell type of interest for treatment within the patient's own body. This technology may be used to repair injured tissue or restore function of aging tissue, including organs, blood vessels and nerve cells.

Results of the regenerative medicine study published in the journal Nature Nanotechnology.

"By using our novel nanochip technology, injured or compromised organs can be replaced. We have shown that skin is a fertile land where we can grow the elements of any organ that is declining," said Dr. Chandan Sen, director of Ohio State's Center for Regenerative Medicine & Cell Based Therapies, who co-led the study with L. James Lee, professor of chemical and biomolecular engineering with Ohio State's College of Engineering in collaboration with Ohio State's Nanoscale Science and Engineering Center.

Researchers studied mice and pigs in these experiments. In the study, researchers were able to reprogram skin cells to become vascular cells in badly injured legs that lacked blood flow. Within one week, active blood vessels appeared in the injured leg, and by the second week, the leg was saved. In lab tests, this technology was also shown to reprogram skin cells in the live body into nerve cells that were injected into brain-injured mice to help them recover from stroke.

"This is difficult to imagine, but it is achievable, successfully working about 98 percent of the time. With this technology, we can convert skin cells into elements of any organ with just one touch. This process only takes less than a second and is non-invasive, and then you're off. The chip does not stay with you, and the reprogramming of the cell starts. Our technology keeps the cells in the body under immune surveillance, so immune suppression is not necessary," said Sen, who also is executive director of Ohio State's Comprehensive Wound Center.

TNT technology has two major components: First is a nanotechnology-based chip designed to deliver cargo to adult cells in the live body. Second is the design of specific biological cargo for cell conversion. This cargo, when delivered using the chip, converts an adult cell from one type to another, said first author Daniel Gallego-Perez, an assistant professor of biomedical engineering and general surgery who also was a postdoctoral researcher in both Sen's and Lee's laboratories.

TNT doesn't require any laboratory-based procedures and may be implemented at the point of care. The procedure is also non-invasive. The cargo is delivered by zapping the device with a small electrical charge that's barely felt by the patient.

"The concept is very simple," Lee said. "As a matter of fact, we were even surprised how it worked so well. In my lab, we have ongoing research trying to understand the mechanism and do even better. So, this is the beginning, more to come."

Researchers plan to start clinical trials next year to test this technology in humans, Sen said.

Read more at Science Daily

Record for fastest light pulse set

University of Central Florida Professor Zenghu Chang broke the record for the fastest light pulse.

A research team at the University of Central Florida has demonstrated the fastest light pulse ever developed, a 53-attosecond X-ray flash.

The group led by Professor Zenghu Chang beat its own record set in 2012: a 67-attosecond extreme ultraviolet light pulse that was the fastest at the time.

At one-quintillionth of a second, an attosecond is unimaginably fast. In 53 attoseconds, light travels less than one-thousandth of the diameter of a human hair.

In the same way high-speed cameras can record slow-motion video of flying bullets, attosecond light pulses allow scientists to capture images of fast-moving electrons in atoms and molecules with unprecedented sharpness.

As reported Aug. 4 in Nature Communications, the pulses Chang has now demonstrated are not just shorter in duration, but also in wavelength. The new light reaches an important spectral region, the so called "water window," where carbon atoms absorb strongly but water does not.

"Such attosecond soft X-rays could be used to shoot slow-motion video of electrons and atoms of biological molecules in living cells to, for instance, improve the efficiency of solar panels by better understanding how photosynthesis works," said Chang, a UCF Trustee Chair Professor in CREOL, The College of Optics & Photonics, and the Department of Physics. Chang is the director of the Institute for the Frontiers of Attosecond Science and Technology (iFAST), located in the Physics Department, where the experiments were carried out.

X-rays interact with the tightly bound electrons in matter and may reveal which electrons move in which atoms, providing another way to study fast processes in materials with chemical element specificity. That capability is invaluable for the development of next-generation logic and memory chips for mobile phones and computers that are a thousand times faster than those in use today.

Read more at Science Daily

The ocean's fastest shark is being threatened by over fishing

Mako shark.

More bad news for sharks.

A new study using satellite tracking by researchers from Nova Southeastern University's Guy Harvey Research Institute (GHRI), the University of Rhode Island and other colleagues shows that the fishing mortality rate of the shortfin mako in the western North Atlantic is considerably higher than previously estimated from catches reported by fishermen. These data suggest that this major ocean apex predator is experiencing overfishing, raising serious concerns about whether the current levels of fishery catches in the North Atlantic are sustainable.

The new study has been published in the Journal Proceedings of the Royal Society B.

"Traditionally, the data obtained to determine the rate of fishing mortality, a key parameter used to help gauge the health of shark stocks, has depended largely on fishermen self-reporting any mako sharks they may have caught," said Mahmood Shivji, Ph.D., senior author of the study and director of the NSU's GHRI. "The challenge is that not all fishermen report the same way or some may underreport or even not report their mako shark captures at all, so the these catch data are known to be of questionable reliability."

Shivji said that near real-time tracking of mako sharks using satellite tags and directly seeing how many were captured allowed researchers to bypass the dependency on self-reporting by fishermen.

"Using satellite tags for makos and possibly other fished species can be a time-efficient way and a fisheries-independent tool for gathering useful fisheries-interaction data, including answering fundamental questions about the levels of fishing survival and mortality," said Michael Byrne, Ph.D., the paper's lead author and postdoctoral fellow at NSU's GHRI when the study was done. "The tracking data also showed these mako sharks entered the management zones of 19 countries, underscoring how critical it is for countries to work together closely to manage and conserve these long-distance oceanic travelers." When the researchers began to gather, compile, disaggregate and review the data, the results were startling.

An unexpectedly high proportion, 30% of the 40 satellite tagged sharks, were captured in fisheries. After modelling the probability that a mako shark would survive a year without being captured (a 72% chance) and calculating the fishing mortality rates, researchers determined that the rate at which shortfin makos were being killed in fisheries was actually 10 times higher than previously believed.

"From a conservation and protection point of view, this is huge," said Bradley Wetherbee, Ph.D., a research scientist from the University of Rhode Island's Department of Biological Sciences and a member of NSU's GHRI. "It's vital that we have the most accurate data possible to aid decision-makers in managing marine life populations sustainably. If they have inaccurate information, it's much more difficult to make the correct decisions for properly managing populations. Everyone wants the populations managed in a sustainable way."

The tracks of the tagged mako sharks, including the ones captured, can be viewed online on NSU's GHRI shark tracking website.

Globally, many shark species have seen significant declines in their numbers, with fisheries overexploitation cited as a major cause. This can happen in many ways -- some shark species are specifically targeted while others are captured by accident (called bycatch.) No matter how sharks are taken from the world's oceans, the fact remains that the current levels of removal for many species are unsustainable.

The researchers stress that the work they are doing has the goal of providing the most accurate information possible to those in positions to take action to manage mako and other shark species. They both say that the goal is create successful fisheries management and conservation -- to avoid declining populations, and to do that, we must have as much accurate data as possible.

Read more at Science Daily

Possible explanation for the dominance of matter over antimatter in the Universe

An electron-neutrino interaction observed by the T2K experiment. The neutrino interacts with a water molecule in the detector volume producing an electron which in turn emits Cherenkov light while travelling across the detector. This light is collected by special photo-sensors and converted into a measurable electric signal.

Neutrinos and antineutrinos, sometimes called ghost particles because difficult to detect, can transform from one type to another. The international T2K Collaboration announces a first indication that the dominance of matter over antimatter may originate from the fact that neutrinos and antineutrinos behave differently during those oscillations. This is an important milestone towards the understanding of our Universe. A team of particle physicists from the University of Bern provided important contributions to the experiment.

The Universe is primarily made of matter and the apparent lack of antimatter is one of the most intriguing questions of today's science. The T2K collaboration, with participation of the group of the University of Bern, announced today in a colloquium held at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan, that it found indication that the symmetry between matter and antimatter (so called "CP-Symmetry") is violated for neutrinos with 95% probability.

Different Transformation of Neutrinos and Antineutrinos

Neutrinos are elementary particles which travel through matter almost without interaction. They appear in three different types: electron- muon- and tau-neutrinos and their respective antiparticle (antineutrinos). In 2013 T2K discovered a new type of transformation among neutrinos, showing that muon-neutrinos transform (oscillate) into electron-neutrinos while travelling in space and time. The outcome of the latest T2K study rejects with 95% probability the hypothesis that the analogous transformation from muon-antineutrinos to electron-antineutrinos takes place with identical chance. This is a first indication that the symmetry between matter and antimatter is violated in neutrino oscillations and therefore neutrinos also play a role in the creation of the matter-antimatter asymmetry in the universe.

"This result is among the most important findings in neutrino physics over the last years," said Prof. Antonio Ereditato, director of the Laboratory of High Energy Physics of the University of Bern and leader of the Bern T2K group, "and it is opening the way to even more exciting achievements, pointing to the existence of a tiny but measurable effect." Ereditato added: "Nature seems to indicate that neutrinos can be responsible for the observed supremacy of matter over antimatter in the Universe. What we measured justifies our current efforts in preparing the next scientific enterprise, DUNE, the ultimate neutrino detector in USA, which should allow reaching a definitive discovery."

In the T2K experiment a muon-neutrino beam is produced at the Proton Accelerator Research Complex (J-PARC) in Tokai on the east coast of Japan and is detected 295 kilometres away by the gigantic Super-Kamiokande underground detector ("T2K" stands for "Tokai to Kamiokande"). The neutrino beam needs to be fully characterized immediately after production, that means before neutrinos start to oscillate. For this purpose, the ND280 detector was built and installed close to the neutrino departing point.

Read more at Science Daily

How do birds get their colors?

This female common eider, Somateria mollissima, was photographed by Ismael Galvan in Northern Iceland. The complex plumage pattern is produced by melanin pigments.

Birds' feathers, or plumage, are some of the most strikingly variable animal characteristics that can be observed by the naked eye. The patterns that we see in birds' feathers are made up of intricate combinations of mottles, scales, bars, and spots. But, how are these colors and patterns made?

We already know why birds have colored feathers. For many birds, plumage coloration may make them less visible to predators by helping them to blend in to their surroundings, or more appealing to potential mates by helping them to stand out from their peers. These aspects are well known. A greater mystery has been how the patterns are created on a cellular level.

Dr. Ismael Galván and his team of expert researchers studied plumage coloration to see what types of pigments were present in birds' complex feather patterns. Plumage coloration mainly happens courtesy of two types of pigments: melanins, which produce a range of black, grey, brown, and orange colors, and carotenoids, which are used by specialized feather structures to generate brighter color hues.

Birds cannot produce carotenoids on their own. For feathers with bright colors, birds must consume food items that contain these pigments, and the carotenoids circulate through the bloodstream and to the feather follicles. Birds' bodies do not have direct cellular control of synthesizing and depositing carotenoids; nor do they have control of the specialized feather structures, which react to the consumed carotenoids with a mechanism that is not regulated by specialized cells.

Melanins, on the other hand (or should that be "on the other wing"), are synthesized by in the birds' bodies in special cells called "melanocytes," which work together with feather follicles to achieve a fine control of pigmentation. Although studies frequently focus on carotenoids in bird coloration, Dr. Galván and group are the first to test whether melanins are indeed the only pigmentary element that birds' bodies directly control on a cellular level.

Galván says, "Knowing beforehand that different pigments and structures produce different types of colors in feathers, we examined the appearance of the plumage of all species of extant birds and determined if the color patches that they contain are produced by melanins or by other pigmentary elements. We also identified those plumage patterns that can be considered complex, defining them as those formed by combinations of two or more discernible colors that occur more than two times uninterruptedly through the plumage." This study was very large in scope, examining about 9,000 bird species, with the goal of supporting a general conclusion for all birds, to finally answer the question of how birds develop colorful and detailed patterns.

The team found that about 32% of the species studied have complex plumage patterns, with the vast majority of these complex patterns produced by melanins rather than carotenoids. Metaphorically, if the birds were artists, they would use carotenoids as a broad brush to produce color patches, with melanins as a detail paint brush to produce more intricate designs.

Read more at Science Daily

Trapdoor spider may have dispersed across the ocean from Africa to Australia

Common brown trapdoor spider, Arbanitis gracilis.

An Australian trapdoor spider may have crossed the ocean from Africa rather than being the product of geographical separation, according to a study published August 2, 2017 in the open-access journal PLOS ONE by Sophie Harrison from The University of Adelaide, Australia, and colleagues.

Darwin proposed that long-distance dispersal explained the evolutionary history of many groups of organisms. However, the distances across Southern Hemisphere oceans are so great that species there were generally postulated to be the products of the separation of Gondwana. With the advent of modern molecular techniques, however, this debate is now being revisited.

A good test case in this debate is an Australian trap door spider (Moggridgea rainbowi) that is sedentary and settles within a few meters of where it hatched, but was recently confirmed to belong to an otherwise African genus. To determine when the Australian species diverged from its African relatives, Harrison and colleagues compared six genes (five nuclear and one mitochondrial) from seven M. rainbowi on Kangaroo Island, Australia, and five Moggridgea from South Africa.

The researchers found that M. rainbowi diverged from its African relatives some two million years ago. This is long after the 110 million years needed to fit the hypothesis that M. rainbowi is the product of Gondwana's separation. Moreover, M. rainbowi diverged before people colonized Kangaroo Island, refuting the hypothesis that the species is the product of human introduction. Rather, the best fit with the divergence date is that M. rainbowi underwent long-distance dispersal from Africa to Australia.

There is precedent for oceanic dispersal of Moggridgea: the spiders are also found on the Comoros, volcanic islands 340 kilometers from mainland Africa. The researchers suggest that M. rainbowi could have dispersed the 10,000 kilometers from Africa to Australia by rafting on, for example, a large chunk of vegetation or debris that washed out to sea.

From Science Daily