Culture

When it comes to choosing which other species to hang out with, wild animals quite literally change their minds with the weather, a new University of Liverpool study reveals.

The findings, which are published in the journal Philosophical Transactions of the Royal Society B, could help conservationists better predict the risk of extinction faced by endangered species.

"In the wild, a species always exists as part of a community of other species, which affect its survival. These interactions are crucial when it comes to predicting extinction risk: if we focus only on single species in isolation we may get it very wrong," explains the leader of the research team, Dr Jakob Bro-Jørgensen.

In this study the researchers aimed to uncover if species alter their preference for different social partners when their environment changes - a central question to forecast how current environmental changes caused by humans are likely to affect animal populations and communities.

Over a year, they followed the distribution in space and time of a dozen species inhabiting the Masai Mara plains in East Africa, including buffaloes, giraffes, zebras, antelopes, ostriches and warthogs, to see how the strength of social attraction within individual species pairs changed between the wet and dry season.

All of the savannah herbivore species underwent seasonal changes when it came to their social groupings, with rainfall affecting half of all the possible species pairs.

The researchers suggest that this could be due to a number of reasons, including species migration, climate adaption and feeding preferences. For example, the presence of migrating wildebeest during the dry season may provide a welcome social partner for some, like zebra, but be avoided by others, like buffalo, while arid-adapted species, such as gazelles, ostrich and warthog, may group together during the dry season but separate during the wet season.

"Our study shows that the dramatic changes that humans are causing to the environment at present, be it through climate change, overhunting or habitat fragmentation, will likely create indirect consequences by changing the dynamics of ecological communities," says Dr Bro-Jørgensen.

"This can cause unexpected declines in species if critical bonds with other species are broken. A particular concern is when animals find themselves in novel conditions outside the range which they have been shaped by evolution to cope with," he adds.

Following on from this study, the researchers now plan to investigate how predation and feeding strategies interact to drive the formation of mixed-species groups.

BIRMINGHAM, Ala. - Bone marrow contains biological factories, which pump out billions of new blood cells daily. The non-blood cells that maintain this production also have the potential to produce bone, fat and cartilage. This output all starts from stem cells that have the ability to differentiate into various types of cells.

Knowledge of the genes that control this differentiation and the paths that cells take to their final, differentiated forms is an important biological question because dysregulation of this process is linked to pathologies -- such as obesity, osteoporosis, cancer, tooth loss and aging. Knowledge of the mechanisms that regulate cell differentiation could lead to improved understanding of the pathogenesis of these disorders and eventually new treatments. But the search is challenging because bone marrow is a complex mix of cells in small niches and with largely unknown interactions and relationships.

Research led by Robert Welner, Ph.D., assistant professor in the University of Alabama at Birmingham Division of Hematology and Oncology, has now mapped distinct bone marrow niche populations and their differentiation paths for the bone marrow factory that starts from mesenchymal stromal cells and ends with three types of cells -- fat cells, bone-making cells and cartilage-making cells. Respectively, those cells are called adipocytes, osteoblasts and chondrocytes. This non-hematopoietic cell system is distinct from another production line in the bone marrow -- the hematopoietic system -- that makes red blood cells, blood-clotting cells and cells of the immune system.

Welner and colleagues at UAB, Harvard Medical School and Beth Deaconess Medical Center, Boston, have published their findings in Cell Reports. Their main research tool was single-cell RNA sequencing, which identified mRNA transcripts from genes in 2,847 individual bone marrow cells of the non-hematopoietic system. By sequencing these RNAs, researchers could tell which genes had been turned on or off at different steps on differentiation pathways.

"The single-cell RNA sequencing gene expression profiles generated permit a real-time depiction of dynamic processes associated with fate choices within the bone marrow microenvironment," said Welner, who is also an associate scientist with the O'Neal Comprehensive Cancer Center at UAB. "Our study provides a landscape for a better understanding of transcriptional networks regulating differentiation of bone marrow microenvironment cells."

A major finding was a detailed characterization of three distinct paths in a simple, branching hierarchy of differentiation, starting from mesenchymal stem cells, or MSCs, and ending with pre-adipocytes, pro-osteoblasts and pro-chondrocytes. In all, they identified seven distinct cell states in two branching pathways. One branch was MSCs to adipocyte progenitors to pre-adipocytes. The other was from MSCs to osteoblast/chondrocyte progenitors to pre-osteoblasts/chondrocytes, and finally a split to either pro-osteoblasts or pro-chondrocytes.

For each of these unique subpopulations, they identified gene signatures, and they demonstrated how several transcription factors -- gene control proteins that alter the rate of transcription from DNA to mRNA -- influence fate decisions to specific bone marrow lineages. The dataset the researchers created and the analysis tools they used are publicly available and will serve as a resource for future studies investigating stromal cell differentiation.

An important control in the research, Welner says, and one that should be used in all single-cell RNA sequencing research, was validation studies. These included fate-marked reporters and knockdowns of transcription factors previously reported to govern bone and fat differentiation. The knockdowns allowed researchers to assay differentiation potential in cell culture for the lineages they identified through single-cell RNA sequencing. The validation studies by Welner and colleagues all supported the findings from their single-cell RNA sequencing.

INDIANAPOLIS--New research from the Alzheimer's Disease Metabolomics Consortium (ADMC) and Alzheimer's Disease Neuroimaging Initiative (ADNI) has uncovered novel connections between liver dysfunction and Alzheimer's disease (AD), paving a new path toward a systems level view of Alzheimer's relevant for early detection and ultimately for prevention.

The study, published today in JAMA Network Open [insert link], was led by IU School of Medicine radiology professor Kwangsik Nho, PhD and explores the relationship between blood-based biochemical markers of liver function and established Alzheimer's disease biomarkers including multi-modal neuroimaging. With increasing evidence linking Alzheimer's disease to diabetes or high cholesterol and other systemic illnesses, Nho and colleagues discovered an association between liver function and Alzheimer's, which adds to the understanding of metabolic dysfunction in the disease.

Researchers evaluated more than 1,500 participants from the National Institute of Aging (NIA)-sponsored ADNI over two years using five serum-based liver function assays, which measure enzymes predominantly found in the liver. By using the peripheral biochemical markers, the team was able to uncover evidence of metabolic disturbance and gain a new perspective on altered liver enzymes association with both cognitive impairment and AD pathophysiology including amyloid-β and phosphorylated tau in cerebrospinal fluid (CSF) and reduced brain glucose metabolism on PET scans.

"This study was a combined effort of the ADNI, a 60-site study, and the ADMC. It represents the new wave of Alzheimer's research, employing a broader systems approach that integrates central and peripheral biology," said Andrew J. Saykin, PsyD, director of the Indiana Alzheimer Disease Center at IU School of Medicine and site principal investigator for the Alzheimer's Disease Metabolomics Consortium. "In this study, blood biomarkers reflecting liver function were related to brain imaging and CSF markers associated with Alzheimer's," Saykin said. "No stone can be left unturned in our attempt to understand the disease and to identify viable therapeutic targets."

Funded by the NIA under its Accelerating Medicine Partnership for Alzheimer's Disease program, this research is a result of international collaboration, led by Rima Kaddurah-Daouk, PhD, of Duke University, that attempts to connect the dots in the body's "gut-liver-brain" communication pathway and relate this to AD. "This is a new paradigm for Alzheimer's research," Nho said. "Until now, we only focused on the brain. Our research shows that by using blood biomarkers, we can still focus on the brain but also find evidence of Alzheimer's and improve our understanding of the body's internal signaling."

"While we have focused for too long on studying the brain in isolation, we now have to study the brain as an organ that is communicating with and connected to other organs that support its function and that can contribute to its dysfunction. The concept emerges that Alzheimer's disease might be a systemic disease that affects several organs including the liver," said Kaddurah-Daouk. The study's focus outside the brain aligns with known risk factors for Alzheimer's disease, including metabolic disorders. According to Nho, looking elsewhere in the body for signals correlated with the disease can provide important clues toward detection and ultimately prevention.

Not only does this research shed light on the connection between the liver and brain, but this line of research is expected to ultimately enable physicians to provide more personalized patient care. Through IU's Grand Challenge Precision Health Initiative and the ADMC precision medicine approach, researchers and physicians can focus on how a patient's environment, genes and lifestyle impact their overall health. Instead of a one-size-fits-all tactic, precision medicine allows researchers and physicians to more accurately predict and prevent devastating diseases, like Alzheimer's. The NIA-ADMC research program opens the door for physicians treating patients with liver dysfunction to ensure they aren't also exhibiting early-stage Alzheimer's disease.

A piping hot planet discovered by NASA's Transiting Exoplanet Survey Satellite (TESS) has pointed the way to additional worlds orbiting the same star, one of which is located in the star's habitable zone. If made of rock, this planet may be around twice Earth's size.

The new worlds orbit a star named GJ 357, an M-type dwarf about one-third the Sun's mass and size and about 40% cooler that our star. The system is located 31 light-years away in the constellation Hydra. In February, TESS cameras caught the star dimming slightly every 3.9 days, revealing the presence of a transiting exoplanet -- a world beyond our solar system -- that passes across the face of its star during every orbit and briefly dims the star's light.

"In a way, these planets were hiding in measurements made at numerous observatories over many years," said Rafael Luque, a doctoral student at the Institute of Astrophysics of the Canary Islands (IAC) on Tenerife who led the discovery team. "It took TESS to point us to an interesting star where we could uncover them."

The transits TESS observed belong to GJ 357 b, a planet about 22% larger than Earth. It orbits 11 times closer to its star than Mercury does our Sun. This gives it an equilibrium temperature -- calculated without accounting for the additional warming effects of a possible atmosphere -- of around 490 degrees Fahrenheit (254 degrees Celsius).

"We describe GJ 357 b as a 'hot Earth,'" explains co-author Enric Pallé, an astrophysicist at the IAC and Luque's doctoral supervisor. "Although it cannot host life, it is noteworthy as the third-nearest transiting exoplanet known to date and one of the best rocky planets we have for measuring the composition of any atmosphere it may possess."

But while researchers were looking at ground-based data to confirm the existence of the hot Earth, they uncovered two additional worlds. The farthest-known planet, named GJ 357 d, is especially intriguing.

"GJ 357 d is located within the outer edge of its star's habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the Sun," said co-author Diana Kossakowski at the Max Planck Institute for Astronomy in Heidelberg, Germany. "If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface."

Without an atmosphere, it has an equilibrium temperature of -64 F (-53 C), which would make the planet seem more glacial than habitable. The planet weighs at least 6.1 times Earth's mass, and orbits the star every 55.7 days at a range about 20% of Earth's distance from the Sun. The planet's size and composition are unknown, but a rocky world with this mass would range from about one to two times Earth's size.

Even through TESS monitored the star for about a month, Luque's team predicts any transit would have occurred outside the TESS observing window.

GJ 357 c, the middle planet, has a mass at least 3.4 times Earth's, orbits the star every 9.1 days at a distance a bit more than twice that of the transiting planet, and has an equilibrium temperature around 260 F (127 C). TESS did not observe transits from this planet, which suggests its orbit is slightly tilted -- perhaps by less than 1 degree -- relative to the hot Earth's orbit, so it never passes across the star from our perspective.

To confirm the presence of GJ 357 b and discover its neighbors, Luque and his colleagues turned to existing ground-based measurements of the star's radial velocity, or the speed of its motion along our line of sight. An orbiting planet produces a gravitational tug on its star, which results in a small reflex motion that astronomers can detect through tiny color changes in the starlight. Astronomers have searched for planets around bright stars using radial velocity data for decades, and they often make these lengthy, precise observations publicly available for use by other astronomers.

Luque's team examined ground-based data stretching back to 1998 from the European Southern Observatory and the Las Campanas Observatory in Chile, the W.M. Keck Observatory in Hawaii, and the Calar Alto Observatory in Spain, among many others.

Evaluating body composition, especially appendicular muscle mass, can be an effective strategy for predicting longevity in people over 65 years of age, according to a study conducted by researchers at the University of São Paulo’s Medical School (FM-USP) in Brazil.

The appendicular muscles are the muscles that move the appendages or extremities – the arms and legs. They also play a key role in stabilizing the shoulders and hips.

The researchers studied a group of 839 men and women over the age of 65 for approximately four years. They observed that all-cause mortality risk increased nearly 63-fold during the follow-up period in women with low appendicular muscle mass and 11.4-fold in men.

An article with results of the study, which was supported by FAPESP, is published in the Journal of Bone and Mineral Research.

“We evaluated the body composition of this group, focusing on appendicular muscle mass, subcutaneous fat and visceral fat. We then sought to determine which of these factors could predict mortality in the ensuing years. We concluded that the key factor was the amount of appendicular lean mass,” Rosa Maria Rodrigues Pereira, Full Professor and Head of Rheumatology at FM-USP and principal investigator for the study, told Agência FAPESP.

Body composition was determined by dual energy X-ray absorptiometry (DXA), also known as bone density scanning, using a densitometer purchased with funding from FAPESP during a previous project led by Pereira to assess the prevalence of osteoporosis and fractures in older women living in Butantã, a neighborhood in western São Paulo city. The same cohort of individuals over 65 years of age was studied in both projects.

“Participants were selected on the basis of the census performed by IBGE [Brazil’s national census bureau]. The sample was representative of the older members of the country’s population,” Pereira said.

The study sample comprised 323 men (39%) and 516 women (61%). The frequency of low muscle mass was approximately 20% for both men and women.

Silent disease

The gradual loss of muscle mass and quality associated with aging is known as age-related sarcopenia. Approximately 46% of Brazilians aged 80 or older have sarcopenia, according to the Brazilian Association of Geriatrics and Gerontology.

Especially when combined with osteoporosis, sarcopenia can increase the vulnerability of older people in that they become more prone to falls, fractures and other physical injuries. Low bone mineral density, particularly in the femur, was shown to correlate with mortality in elderly individuals by research published in 2016.

Pereira and her group developed an equation to determine which individuals can be considered to have sarcopenia based on the characteristics of the community studied.

“According to the most widely used criteria [appendicular lean mass in kg divided by height squared in m], most of the individuals identified as having sarcopenia are lean. However, our sample had a higher-than-average BMI [body mass index], so we substituted muscle mass for fat mass. Subjects with muscle mass that was 20% below average were classified as having sarcopenia,” Pereira said.

The researchers discussed this topic in articles published in Osteoporosis International in 2013 and 2014.

In addition to bone density, the researchers also analyzed blood samples and responses to questionnaires to evaluate diet, physical activity, smoking, consumption of alcoholic beverages, and the presence of chronic diseases such as diabetes, high blood pressure and dyslipidemia (abnormally elevated levels of fat in the blood).

At the end of the four-year period, 15.8% (132) of the volunteers had died; 43.2% had died from cardiovascular problems. The mortality rate was 20% for the men and 13% for the women in the sample.

“We then conducted a number of statistical analyses to detect differences between the subjects who died and those who remained alive, particularly, whether it was possible to predict a person’s death on the basis of body composition measured by the DXA examination,” Pereira said.

Differences

Generally, subjects who died were older, exercised less, and suffered more from diabetes and cardiovascular problems than those who remained alive. In the case of the women who died, they also had decreased BMIs. The men who died were more likely to suffer falls. All these variables were fed into the statistical model and adjusted for the end-result to show which body composition factor correlated best with mortality risk.

Only low muscle mass was found to be significant in the women, considering the adjustment variables, while visceral fat was also significant among the men. The mortality risk doubled with each 6 cm2 increase in abdominal fat. Curiously, a higher proportion of subcutaneous fat had a protective effect in the men.

“We found that other parameters also negatively influenced mortality in the men, statistically reducing the significance of appendicular muscle mass. In the women, however, muscle mass stood out as a key factor and hence had more influence,” Pereira said.

Menopause-related hormone changes may help explain the difference between men and women. “The rapid and significant transition from a protective estrogenic environment to a deleterious hypoestrogenic environment, which is particularly adverse for the cardiovascular system, may make the protective metabolic role of skeletal muscles, including the production of anti-inflammatory cytokines, more important in the postmenopause period. This hormone change is far less abrupt in men,” she said.

Loss of muscle mass, which occurs naturally after the age of 40, can be unnoticed owing to weight gain, which is also common in middle age. Between 1% and 2% of muscle mass is lost annually after the age of 50, according to estimates. The factors that may accelerate muscle loss include sedentary habits, a protein-poor diet, chronic diseases and hospitalization.

In addition to their obvious importance in posture, balance and movement, the skeletal muscles have other functions that are essential to the body. They help regulate blood sugar by consuming energy during contraction and maintain the body temperature by trembling when cold. They also produce messenger hormones, such as myokinase, that assist communication with different organs and influence inflammatory responses.

The good news is that sarcopenia is preventable and can even be reversed by physical exercise, especially muscle toning. Attention to protein ingestion is also recommended.

The article “Association of appendicular lean mass and subcutaneous and visceral adipose tissue with mortality in older Brazilians: The São Paulo Ageing & Health Study” by Felipe M. de Santana, Diogo S. Domiciano, Michel A. Gonçalves, Luana G. Machado, Camille P. Figueiredo, Jaqueline B. Lopes, Valéria F. Caparbo, Liliam Takayama, Paulo R. Menezes and Rosa M. R. Pereira can be retrieved from: onlinelibrary.wiley.com/doi/pdf/10.1002/jbmr.3710.

Journal

Journal of Bone and Mineral Research

DOI

10.1002/jbmr.3710

ITHACA, N.Y. - NASA's Transiting Exoplanet Survey Satellite (TESS), a mission designed to comb the heavens for exoplanets, has discovered its first potentially habitable world outside of our own solar system - and an international team of astronomers has characterized the super-Earth, about 31 light-years away.

In a new paper in the The Astrophysical Journal Letters, a team led by Lisa Kaltenegger, associate professor of astronomy and director of Cornell's Carl Sagan Institute, models the conditions under which the planet -- discovered in early 2019 -- could sustain life.

“This is exciting, as this is TESS’s first discovery of a nearby super-Earth that could harbor life – TESS is a small, mighty mission with a huge reach,” said Kaltenegger, a member of the TESS science team.

As this super-Earth exoplanet is more massive than our own blue planet, Kaltenegger said this discovery will provide insight into Earth's heavyweight planetary cousins. "With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth and we could pick out signs of life with upcoming telescopes soon to be online," she said.

Astronomers from the Institute of Astrophysics of the Canary Islands and the University of La Laguna, both of Spain, announced the discovery of the system July 31 in the journal Astronomy & Astrophysics. They showed that the distant solar system - with a diminutive M-type dwarf sun, about one-third the size of our own sun - harbors three planets, with one of those in that system's habitable zone: GJ 357 d.

Last February, the TESS satellite observed that the dwarf sun GJ 357 dimmed very slightly every 3.9 days, evidence of a transiting planet moving across the star's face. That planet was GJ 357 b, a so-called "hot Earth" about 22 percent larger than Earth, according to the NASA Goddard Space Flight Center, which guides TESS.

Follow up observations from the ground led to the discovery of two more exoplanetary siblings: GJ 357 c and GJ 357 d. The international team of scientists collected Earth-based telescopic data going back two decades - to reveal the newly found exoplanets' tiny gravitational tugs on its host star, according to NASA.

Exoplanet GJ 357 c sizzles at 260 degrees Fahrenheit, and has at least 3.4 times Earth's mass. However, the system's outermost known sibling planet - GJ 357 d, a super-Earth - could provide conditions just like on Earth and orbits the dwarf star every 55.7 days at a distance about 20 percent of Earth's distance from the Sun. It is not yet known if this planet transits its sun.

Kaltenegger, doctoral candidate Jack Madden and undergraduate student Zifan Lin simulated light fingerprints, climates and remotely detectable spectra for the planet, which could range from a rocky composition to a water world.

Madden explained that investigating new discoveries provides an opportunity to test theories and models. "We built the first models of what this new world could be like," he said. "Just knowing that liquid water can exist on the surface of this planet motivates scientists to find ways of detecting signs of life."

Chicago, July 31, 2019 - The notion that more medical errors occur in July compared to other months due to an influx of new medical school graduates starting their in-hospital training does not apply to heart surgery, according to research in The Annals of Thoracic Surgery, published by Elsevier.

"While the perception of the 'July effect' persists culturally among health care providers, we hope that this study reinforces the fact that hospital systems have in place processes that help provide the highest level of care and ensure patient safety," said Sameer A. Hirji, MD, of Brigham and Women's Hospital in Boston, MA, USA. "Our findings are encouraging."

Researchers from Brigham and Women's Hospital and Harvard University examined data from the Nationwide Inpatient Sample, which is part of a database family developed by the Agency for Healthcare Research and Quality and provides information on more than 35 million hospital admissions.

The group analyzed more than 470,000 standard cardiac procedures such as coronary artery bypass grafting (CABG); aortic valve replacement; mitral valve repair or replacement; and thoracic aortic aneurysm (TAA) replacement that were performed between 2012 and 2014 on adult patients. For each procedure, overall trends were compared by academic year quartiles: Q1 (July to September with the least experienced residents) vs. Q4 (April to June with the most experienced residents). The researchers observed no differences in mortality, in-hospital complications, costs, or length of stay between patients who were treated in Q1 compared to those in Q4.

"Cardiac surgery patients are managed in a multidisciplinary fashion; therefore, the well-being of patients is not solely dependent on one individual, but rather on the entire caregiving team and so may be more resistant to changes in hospital staff," said Rohan M. Shah, MD, MPH. "What this means for patients is that they should not be fearful or concerned about having surgery in July when new residents are starting."

In addition, the study showed that while hospital teaching status did not influence risk-adjusted mortality rates for CABG and TAA replacement surgeries, teaching hospitals did perform better than non-teaching hospitals with lower mortality in Q1 versus Q4 for the aortic and mitral procedures. Dr. Shah explained that this is an important finding with implications for overall resident training and education in the operating room.

The future of surgeon training

Most cardiac surgery teams recognize that July is a "vulnerable" period when "direct and strict" supervision of residents is expected, according to Dr. Hirji. As the year progresses, though, resident autonomy increases.

"The balance between attending supervision and resident autonomy constantly shifts during teaching," said Dr. Hirji. "This is a fine balance and, as indicated by this study, our specialty is doing a great job."

Even so, Dr. Shah said that the effectiveness of traditional training programs versus newer training paradigms, such as the increasingly popular Fast-Track Pathway (4-plus-3 model) and the Integrated Pathway (I-6 program), should be evaluated.

Under the Traditional Pathway, residents complete five years of general surgery training, consisting of clinical rotations through the various surgical disciplines, followed by two to three years of cardiothoracic surgery residency. This results in a surgeon who is trained broadly in general and cardiothoracic surgery.

The 4-plus-3 model includes four years of general surgery training, followed by three years of cardiothoracic residency. The resident is introduced to cardiothoracic surgery earlier in the training pathway, resulting in more time to master skills.

The I-6 program is the newest training model and offers even earlier exposure to cardiothoracic surgery. Residents apply directly to an integrated cardiothoracic surgery residency program for 6 years of comprehensive and total immersion in the diagnosis and management of cardiovascular and thoracic diseases through multidisciplinary training and exposure to related fields such as cardiology, radiology, oncology, and endovascular surgery.

"This study highlights the pivotal role of appropriate resident teaching that doesn't compromise patient outcomes," said corresponding author Tsuyoshi Kaneko, MD . "Patient safety will always be the first priority."

New research from Warwick has worked out how our minds supply all the necessary design features of free will.

Philosophers have laid out these design features over hundreds of years.

How our brains satisfy these features has been a problem that scientists have been unable to solve.

In a new paper, Professor Thomas Hills grounds the design features of free will called for by philosophers in biological reality and sets out a new framework for 'neurocognitive free will', the free will that we have.

Do human beings genuinely have free will? Philosophers and theologians have wrestled with this question for centuries and have set out the 'design features' of free will - but how do our brains actually fulfil them?

A University of Warwick academic has answered this question for the first time in a new paper published today [31] in Proceedings of the Royal Society B.

Professor Thomas Hills from the Department of Psychology set out to bridge the gap between the philosophical arguments for free will and the neurocognitive realities.

In philosophy, elements of free will include the ability to do otherwise - the 'principle of alternative possibilities'; the ability to deliberate; a sense of self; and the ability to maintain goals - 'wanting what you want'.

Drawing on examples from making a morning coffee to taking a penalty kick, and considering organisms from human beings, e-coli, cockroaches, and even robots, Professor Hills argues that our neurocognitive abilities satisfy these requirements through:

1. Adaptive access to unpredictability

2. Tuning of this unpredictability to help us reach high-level goals

3. Goal-directed deliberation via search over internal cognitive representations

4. A role for conscious construction of the self in the generation and choice of alternatives.

Commenting on his paper, Professor Hills said: "Neurocognitive free will - the free will that we have as humans - is a process of generative self-construction. I demonstrate that effortful consciousness samples from our experience in an adaptively exploratory fashion, allowing us to explore ourselves in the construction of alternative futures.

"There is evidence that people who believe in free will are more pro-social. They adopt behaviour that benefits others and society as a whole, and have a greater sense of control of their future - they believe they can influence the future in positive ways. This is important. Neurocognitive free will provides a basis for understanding why they are correct.

"Neurocognitive free will ties our understanding of free will to something real. It also helps us to understand what it means. I suspect it's not what most people think. As Sartre once said, "Freedom is not a triumph". But I think neurocognitive free will gives some hints to how it could be. That will be a focus of future work. "

Irvine, Calif., July 31, 2019 -- University of California, Irvine researchers have made it possible to learn how key human brain cells respond to Alzheimer's, vaulting a major obstacle in the quest to understand and one day vanquish it. By developing a way for human brain immune cells known as microglia to grow and function in mice, scientists now have an unprecedented view of crucial mechanisms contributing to the disease.

The team, led by Mathew Blurton-Jones, associate professor of neurobiology & behavior, said the breakthrough also holds promise for investigating many other neurological conditions such as Parkinson's, traumatic brain injury, and stroke. The details of their study have just been published in the journal Neuron. Link to study: https://www.cell.com/neuron/fulltext/S0896-6273(19)30600-2.

The scientists dedicated four years to devising the new rodent model, which is considered "chimeric." The word, stemming from the mythical Greek monster Chimera that was part goat, lion and serpent, describes an organism containing at least two different sets of DNA.

To create the specialized mouse, the team generated induced pluripotent stem cells, or iPSCs, using cells donated by adult patients. Once created, iPSCs can be turned into any other type of cell. In this case, the researchers coaxed the iPSCs into becoming young microglia and implanted them into genetically-modified mice. Examining the rodents several months later, the scientists found about 80-percent of the microglia in their brains was human, opening the door for an array of new research.

"Microglia are now seen as having a crucial role in the development and progression of Alzheimer's," said Blurton-Jones. "The functions of our cells are influenced by which genes are turned on or off. Recent research has identified over 40 different genes with links to Alzheimer's and the majority of these are switched on in microglia. However, so far we've only been able to study human microglia at the end stage of Alzheimer's in post-mortem tissues or in petri dishes."

In verifying the chimeric model's effectiveness for these investigations, the team checked how its human microglia reacted to amyloid plaques, protein fragments in the brain that accumulate in people with Alzheimer's. They indeed imitated the expected response by migrating toward the amyloid plaques and surrounding them.

"The human microglia also showed significant genetic differences from the rodent version in their response to the plaques, demonstrating how important it is to study the human form of these cells," Blurton-Jones said.

"This specialized mouse will allow researchers to better mimic the human condition during different phases of Alzheimer's while performing properly-controlled experiments," said Jonathan Hasselmann, one of the two neurobiology & behavior graduate students involved in the study. Understanding the stages of the disease, which according to the Alzheimer's Association can last from two to 20 years, has been among the challenges facing researchers.

Neurobiology & behavior graduate student and study co-author Morgan Coburn said: "In addition to yielding vital information about Alzheimer's, this new chimeric rodent model can show us the role of these important immune cells in brain development and a wide range of neurological disorders."

Getting reliable precipitation data from the past has proven difficult, as is predicting regional changes for climate models in the present. A combination of isotope techniques developed by researchers at Argonne and UChicago may help resolve both.

The Negev desert, which covers half of Israel’s land mass, is so dry that parts of it get less than three inches of water a year. So dry, its climatological term is “hyperarid.” But like most places on Earth, the region evolved to its present condition after eons of changes in climate and geology.

Today, despite its parched exterior, there is still water under the Negev. Understanding where it came from, how much is there, and what’s happening to it is critical to the security and allocation of that crucial resource.

Researchers at Ben-Gurion University of the Negev in Israel are collaborating with colleagues at the U.S. Department of Energy’s Argonne National Laboratory and the University of Chicago to better understand the Nubian Sandstone Aquifer system, which lies beneath a large portion of the Negev and other parts of Israel.

“To our knowledge, this was the first time that groundwater could directly be used as a climate archive on these long timescales.” — Jake Zappala, postdoctoral appointee, TRACER Center

By combining Argonne’s pioneering radiokrypton dating technique with other isotopic fingerprints of the water’s composition, the researchers are not only able to tell when that water was deposited, but where it came from and the climate conditions that produced it nearly 400,000 years ago. The result marks the first time that scientists have been able to use groundwater to build a picture of ancient hydro-climates dating back that far.

An article describing the research, “Radiokrypton unveils dual moisture sources of a deep desert aquifer,” was published July 29, in Proceedings of the National Academy of Sciences (PNAS) online.

Trapping atoms for clues

“The aquifers beneath the Negev don’t get replenished today, so apparently there were times when there was much more rain in the region that collected underground,” says Peter Mueller, principal physicist at Argonne’s Trace Radioisotope Analysis Center (TRACER).

To determine when and how that might have occurred, the team collected water from more than 20 wells in the area, then separated out the krypton gas and analyzed it using a technology called Atom Trap Trace Analysis (ATTA), a technique first developed at Argonne to support nuclear physics measurements.

ATTA measures water for traces of the rare krypton (Kr) isotope 81Kr, which can date water within a range of approximately 40,000 to 1.5 million years old. This boosts it well beyond the range of radiocarbon dating, which cannot reach accurately beyond about 40,000 years.

The ATTA analysis suggested that the water in the wells accumulated by means of two major “recharging” events that occurred less than 40,000 and near 360,000 years ago. Both periods coincided with generally cooler climates. These “regional humid periods” were ripe for the development of storms that could provide rainfall adequate to replenish the Negev aquifers.

While the 81Kr usually provides an excellent window into the time frame, the distribution data was unexpectedly complex and puzzling. But it showed interesting covariation with deuterium, an isotope of hydrogen heavier than that found in “regular” water.

“We were looking for the delta deuterium, which is a measure of the difference in the ratio of heavy hydrogen to regular hydrogen,” says Jake Zappala, postdoctoral appointee at the TRACER Center. “That number is going to vary for different bodies of water depending on where the water came from and what the weather conditions were, which is important.”

Because deuterium has a heavier mass than hydrogen, it behaves differently, evaporating and condensing at different temperatures. For example, when evaporation happens quickly, as over the Mediterranean Sea, it exhibits a peculiar signature compared to global precipitation trends. Even though it is very rare relative to hydrogen — only one in ten thousand water molecules contains one deuterium atom instead of hydrogen — it can be measured very precisely.

Thus scientists can “fingerprint” such bodies of water based on the particular signature of its stable isotopes. Every climate pattern places its own imprint in that signature, according to the researchers.

“This project shows us these tools could be really transformative, tracing water movement much further than we’ve previously been able to,” said Reika Yokochi, research associate professor in the Department of Geophysical Sciences at the University of Chicago, and the first author of the new study.

Yokochi, who has been collaborating with the ATTA team since 2012, has been key in developing some of the extraction techniques the team currently uses. She hit upon the idea of combining the two data sets to find a correlation between the 81Kr and the deuterium data.

Divining ancient water

From the covariation and the spatial distribution of the data, the team determined that water from the two recharge events came from two distinct sources. About 400,000 years ago, the region was cooler than the present, and moisture is believed to have been delivered from the Atlantic Ocean in the form of tropical plumes. The more recent recharge, less than 40,000 years ago, may have been the result of Mediterranean cyclones during the most recent major glacial event, or Last Glacial Maximum.

“To our knowledge, this was the first time that groundwater could directly be used as a climate archive on these long timescales,” says Zappala. “Using the radiokrypton dating, we are able to say when it rained, and the heavy-to-light water ratio directly tells us something about the weather pattern. So we have a direct correlation between time and regional weather patterns.”

Another interesting point is that the water came from near an earthquake fault zone, notes Yokochi, suggesting that faults can serve as a “wall” that preserves relatively fresh water over hundreds of thousands of years.

“It’s possible that similar water repositories may exist along other fault zones all over the world,” she says.

To date, getting reliable precipitation data from the past has proven difficult, as is predicting regional changes for climate models in the present. The combination of isotope tools used by the team may be part of the answer to resolving both.

As the tools continue to deliver a more reliable picture of past climate events, like the regional water cycles of the Negev, the researchers believe that this data can serve to calibrate present-day models of similar climate phenomena.

“Does your climate model predict the right precipitation pattern 400,000 years ago?” asks Mueller. “Using our data, modelers can calculate back in time to see if their model is right. That is one of the key things that we can provide.”

INDIANAPOLIS -- Researchers have discovered a previously unknown mechanism that causes increased forest water use, advances understanding of soil biogeochemical control of forest water cycles and highlights threats to plants from water stress under acid deposition, according to a new study.

In a study published in the journal Science Advances, the researchers report the mechanism works this way: Sulfuric and nitric acid fall to the ground when fossil fuels are burned, causing acidification of the soil. When that happens, a significant amount of soil calcium washes out of the soil, and then plants suffer from calcium deficiency. Calcium deficiency causes the plants to intensify their use of water.

Lixin Wang, an associate professor in the School of Science at IUPUI, is the senior author of this research, and his Ph.D. student Matthew Lanning is the first author.

This research is funded by the National Science Foundation's Hydrological Sciences program. Other authors of the research team include Todd Scanlon and Howard Epstein at the University of Virginia, Matthew Vadeboncoeur at the University of New Hampshire, Mary Beth Adams at the United States Forest Service, and Daniel Druckenbrod at Rider University.

Calcium plays a unique role in plant cells by regulating the minute pores, called stomata, in the plants' leaves or stems, Wang said. If plants don't have enough calcium, they can't close those pores, and their water use increases. Also, when plants suffer from calcium deficiency, they will pump up more water through transpiration, the process of water movement through a plant and its evaporation from leaves, to meet their calcium demand, he said.

"We hypothesized that the leaching of the soil calcium supply, induced by acid deposition, would increase large-scale vegetation water use," Lanning said. "We present evidence from a long-term whole watershed acidification experiment demonstrating that the alteration of the soil calcium supply by acid deposition can significantly intensify water use."

The researchers found multiple lines of evidence showing that calcium leaching induced by acid deposition not only increased vegetation water use but markedly decreased the soil water pool on the treated watershed.

"When plants are always using a lot of water, it means there will be less water left for people," Wang said. "It also means that these plants are very sensitive to drought. If a drought comes, and they can't close their stomata, they are subject to high levels of mortality due to water stress."

Traditionally, forest water use was considered a function of meteorological factors, species composition and soil water availability. The impacts of soil biogeochemistry on large-scale forest water use had not been investigated.

Nitrate and sulfate deposition are the primary drivers of soil acidification in the northeastern United States and eastern Europe, where atmospheric inputs exceed soil-generated acidity. In the United States and most of Europe, emissions of nitrate and sulfate have been curbed by legislation, but the impacts of acid deposition are still of global concern, especially in areas downwind of major cities or high-production agricultural areas.

HARWELL, UK (July 29, 2019)--All-solid-state batteries, a battery design composed of all solid components, have gained attention as the next major advance beyond lithium ion batteries because of their potential to store more energy while being safer to operate. When capable of being produced in commercial quantities, solid-state batteries would revolutionise electric vehicles (EVs) effectively increasing driveable range or significantly decreasing volume and weight.

Yet solid-state batteries can fail after cycling (repeated charging and discharging) at practical currents, which has been one of the barriers preventing their mass commercialisation.

In a new paper published by Nature Materials entitled "Critical Stripping Current Leads to Dendrite Formation on Plating in Lithium Anode Solid Electrolyte Cells," Faraday Institution researchers at the University of Oxford have taken a step forward in understanding the mechanisms by which solid-state batteries fail--a necessary prerequisite to avoiding such failures.

Dendrites are branching networks of lithium which grow through the solid, ceramic, electrolyte during charging of a battery, causing a short circuit.

"This research adds to our fundamental knowledge of why solid-state batteries behave the way they do. We believe our improved understanding will help to inform approaches to avoid some of the problems at the lithium metal anode in solid electrolyte cells," commented Professor Peter G. Bruce of the University of Oxford's Departments of Materials and Chemistry and Principal Investigator of the Faraday Institution's SOLBAT project, whose team led the research.

Void creation at the anode of solid-state cells has long been recognised, but their role in dendrite formation has not been understood. The study uses a combination of cutting edge electrochemical and imaging techniques to form a fundamental understanding of void formation as a function of cycling and its role in dendrites and cell failure.

Significantly, parameters in the failure model correlate to key physical properties that could be used as "levers" to suppress void formation and cell failure.

"It is key to break down the scientific barriers that prevent the progression to market of technologies that will enable our vision of the future of mobility. The study by Oxford researchers is one early example of a scientific advance that the Faraday Institution was set up to drive," said Tony Harper, Director of the ISCF Faraday Battery Challenge at UK Research & Innovation.

The research: importance of critical current density on stripping

One well-recognised challenge facing scientists studying solid-state batteries is to prevent dendrite growth as batteries are cycled between a charged and uncharged state (as they would repeatedly have to do if they to be used to power EVs).

Another significant problem is void formation between the solid electrolyte and lithium anode (negatively charged electrode) during stripping (discharge of a battery), which leads to a reduced area of contact between those two parts of the battery cell.

It is difficult to separate lithium plating from stripping using an experiment with a battery cell containing the usual two electrodes. In this study researchers used three-electrode cells to study separately the processes of plating and stripping lithium metal at the lithium metal / ceramic interface on battery cycling. Argyrodite, Li6PS5Cl, was chosen as the solid electrolyte. Such sulphides have higher conductivity than oxides and are being pursued as the electrolyte of choice by several companies attempting to commercialise solid-state batteries. Argyrodite has the advantage of being less brittle than other highly conducting sulphides.

The researchers found that if dendrite formation is to be avoided in all-solid-state battery cells, it is vital to cycle the cells below the critical current density at which voids begin to form at the lithium metal / solid electrolyte interface during lithium stripping (CCS). This is the case even when the current density is below the threshold for dendrite formation on plating. When the current density is greater than CCS, voids accumulate on cycling, the lithium / solid electrolyte area of contact decreases correspondingly and as a result the local current density increases until it reaches a value where dendrites form on plating, leading to a short-circuit and cell failure. It may take multiple cycles, but the research demonstrates that cell failure is inevitable if the overall current density is greater than CCS. These results show that it is not just the current density for dendrite formation that is important in achieving cycling of all-solid-state cells at practical current densities; stripping currents are also important.

The researchers also conclude the lithium metal creep is the primary mechanism of transporting lithium metal at the interface.

The team working on this discovery included a mix of theoreticians and experimentalists, in the type of multi-disciplinary research environment that the Faraday Institution fosters.

*The prizes of developing a commercial all solid-state battery for electric vehicles*

Small, non-rechargeable, solid-state batteries are growing in commercial use, for example, in medical implants such as heart monitoring. However, there remain considerable challenges associated with both the fabrication of solid-state batteries at the scale required for use in EVs, and to ensure that such devices operate safely and to acceptable performance levels over the lifetime of the EV.

Current lithium ion batteries used in EVs contain a flammable organic liquid electrolyte, through which charge-carrying lithium ions pass during the charging and discharging of the battery. This liquid presents an inherent (albeit well-managed) safety concern. The replacement of the liquid electrolyte with a solid would remove this fire risk.

Worldwide, significant scientific effort is being expended to develop new battery chemistries that would achieve battery performance (power density and energy density) that would give an EV driving experience aligned with expectations from driving cars with internal combustion engines. The elimination of the need for a liquid electrolyte would be a prerequisite for developing batteries with a lithium metal anode, which could unlock significant performance improvements.

Most of the times you see the eruption of a volcano on TV or the internet, the magma shoots right out of its top. However, it is not so uncommon that the magma erupts from the volcano's flank rather than its summit. After leaving the underground magma chamber, the magma forces its way sideways by fracturing rock, sometimes for tens of kilometres. Then, when it breaches the Earth's surface, it forms one or more vents from which it spills out, sometimes explosively. This for example occurred at Bardarbunga in Iceland in August 2014, and Kilauea in Hawaii in August 2018.

It is a big challenge for volcanologists to guess where magma is heading and where it will breach the surface. A lot of effort is spent on this task as it could help minimise the risk for villages and cities endangered by eruptions. Now, Eleonora Rivalta and her team from the GFZ German Research Centre for Geosciences in Potsdam, together with colleagues from the University Roma Tre and the Vesuvius Observatory of the Italian Istituto Nazionale di Geofisica e Vulcanologia in Naples have devised a new method to generate vent location forecasts. The study is published in the journal Science Advances.

"Previous methods were based on the statistics of the locations of past eruptions", says Eleonora Rivalta. "Our method combines physics and statistics: we calculate the paths of least resistance for ascending magma and tune the model based on statistics." The researchers successfully tested the new approach with data from the Campi Flegrei caldera in Italy, one of the Earth's highest-risk volcanoes.

"Calderas often look like a lawn covered in molehills"

Vents opened at the flank of a volcano are often used by just one eruption. All volcanoes may produce such one-time vents, but some do more than others. Their flanks are punctured by tens of vents whose alignment marks the locations where subsurface magma pathways have intersected the Earth's surface.

At calderas, that is large cauldron-like hollows that form shortly after the emptying of a magma chamber in a volcanic eruption, vents may also open inside and on its rim. That is because they lack a summit to focus eruptions. "Calderas often look like a lawn covered in molehills", says GFZ's Eleonora Rivalta.

Most vents at calderas have only been used once. The resulting scattered, sometimes seemingly random spatial vent distribution threatens wide areas, presenting a challenge to volcanologists who draw forecast maps for the location of future eruptions. Such maps are also necessary for accurate forecasts of lava and pyroclastic flows or the expansion of ash plumes.

Vent forecast maps have so far been mainly based on the spatial distribution of past vents: "Volcanologists often assume that the volcano will behave like it did in the past", says Eleonora Rivalta. "The problem is that often only a few tens of vents are visible on the volcano surface as major eruptive episodes tend to cover or obliterate past eruptive patterns. Hence, as mathematically sophisticated as the procedure can be, sparse data lead to coarse maps with large uncertainties. Moreover, the dynamics of a volcano may change with time, so that vent locations will shift."

Succesful tests at the Campi Flegrei

That is why Rivalta, a trained physicist, together with a team of geologists and statisticians, used volcano physics to improve the forecasts. "We employ the most up-to-date physical understanding of how magma fractures rock to move underground and combine it with a statistical procedure and knowledge of the volcano structure and history. We tune the parameters of the physical model until they match previous eruptive patterns. Then, we have a working model and can use it to forecast future eruption locations", says Eleonora Rivalta.

The new approach was applied in southern Italy to the Campi Flegrei, a caldera close to Naples, which has a population of nearly one million. In the more than ten kilometres wide caldera, about eighty vents have fed explosive eruptions in the last 15,000 years. The approach performs well in retrospective tests, that is correctly forecasting the location of vents that were not used to tune the model, the researchers report.

"The most difficult part was to formulate the method in a way that works for all volcanoes and not just one - to generalise it", Rivalta explains. "We will now perform more tests. If our method works well on other volcanoes too, it may help planning land usage in volcanic areas and forecasting the location of future eruptions with a higher certainty than previously possible."

In one of the first long-term studies to explore how changing soils have impacted plant water uptake, researchers report that plants in soil leached by polluted rain drink more water. These findings reveal acid rain's long-term impact on large-scale forest water cycles, which is critical for understanding future water availability, and they could also help explain some of the uncertainty scientists have encountered in terrestrial biosphere models, the authors say. Matthew Lanning et al. investigated changes in soil water available to plants in the Fernow Experimental Forest of West Virginia, the site of a decades-long watershed acidification experiment. They used 23 years of lysimeter data (which can be used, with precipitation data, to estimate the transfer of water from soil to the atmosphere) along with traditional estimates of the differences between precipitation and water discharge from plants. The estimates show that the acidified watershed had significantly higher soil-to-atmosphere water transfer than occurred in a "control" watershed, which the lysimeter data confirmed by indicating that the average volume of the treated watershed was significantly lower than the control. The researchers suggest that soil acidification causes calcium to leach from the soil--and since calcium plays an important role in signaling plant stomata to close, its absence would cause these water loss-regulating pores to remain open. This would allow evapotranspiration to continue, explaining the plants' greater water uptake.

LA JOLLA, CA - Earth didn't always harbor life. But around 4 billion years ago, something in the environment changed, and systems with biological properties began to emerge. Many scientists believe a lively dance of molecules called amino acids is partly responsible for the shift: Molecules linked up, broke apart and eventually came together to form life as we know it.

We might never know exactly how the process worked, but chemists today have made new discoveries that build upon promising theories for how life formed.

"How chemistry led to complex life is one of the most fascinating questions that mankind has pondered," says Luke Leman, PhD, assistant professor of chemistry at Scripps Research. "There are a lot of theories about the origins of proteins but not so much experimental laboratory support for these ideas."

Leman recently co-led a study into the very recipe for life on early Earth; the research is published in the Proceedings of the National Academy of Sciences. He worked closely with researchers at the Georgia Institute of Technology and the Center for Chemical Evolution, which is supported by the National Science Foundation and NASA.

"The research helps us understand how positively charged peptides could have formed on the pre-biotic earth," says Moran Frenkel-Pinter, PhD, a postdoctoral fellow at Georgia Tech and first author of the paper. Peptides are made when two or more amino acid building blocks link up, leading to the proteins that make up every organism.

Leman, Frenkel-Pinter and many other scientists in this field find it strange that every living thing on our planet forms its proteins from the exact same set of 20 amino acids. Why that specific set? Scientists know there are many more amino acids out there. In fact, meteorites with up to 80 amino acids have landed on Earth.

"In the prebiotic Earth, there would have been a much larger set of amino acids," says Leman, who also is scientific collaborator at the Center for Chemical Evolution. "Is there something special about these 20 amino acids, or did these just get frozen at a moment in time by evolution?"

The new study suggests that life's dependence on these 20 amino acids is no accident. The researchers show that the kinds of amino acids used in proteins are more likely to link up together because they react together more efficiently and have few inefficient side reactions.

This finding gives researchers a look back in time and a working model for testing further theories for the origins of life. Understanding how peptides form is also important for the field of synthetic chemistry, where scientists are striving to design new molecules that can be used for drug therapies and material science.

"This work is a real step toward understanding why certain building blocks are found in the proteins essential for life," says Kathy Covert, program director at the National Science Foundation's Centers for Chemical Innovation, which co-funds the Center for Chemical Evolution. "Through research like this, the Center is realizing its ambitious mission to shed light on the chemistries of biopolymers, a foundation of all living things."

For the experiment, the researchers compared "proteinaceous" amino acids--those used by organisms today--to amino acids that are not present in living things. The researchers knew water evaporation could have created the conditions necessary for amino acids to link together on early Earth, so they used a drying reaction--water evaporates and heat is applied--to mimic the natural conditions that cause amino acids to form peptides.

"With heating and drying cycles, you can form chains of amino acids that are similar to protein structures," Leman says.

Their experiments showed that proteinaceous amino acids are more likely to spontaneously link to form large "macromolecules" without requiring any other ingredients, such as enzymes or activating agents. This linkage is an important step in forming a protein.

The proteinaceous amino acids seemed to prefer reactivity through a part of their structure called the alpha-amine. They mostly formed linear, protein-like backbone "topologies" (geometric formations). This tendency could have given these amino acids a head start in folding and binding, leading eventually to proteins.

Based on the chemistry they observed, the scientists now have a possible explanation for the selection of the positively charged amino acids found in today's proteins.

"This is a purely chemical driving force that could have led to the selection of certain amino acids over other ones," says Leman.

Loren Williams, PhD, professor at Georgia Tech and co-leader of the study, says the research gives chemists a starting point for understanding how life could have started on early Earth, also called the Hadean Earth. "We are starting to understand how purely chemical processes, based on those of the Hadean Earth, can produce molecules that have surprising similarities to biological polymers," says Williams, who is also a member of the CCE.

Going forward, the researchers would like to investigate how these amino acids interact with RNA, the ingredient on early that may have made the next step in evolution possible.

"It will be interesting to learn how these positively charged ancestors of proteins cooperate with negatively-charged molecules such as RNA," says Frenkel-Pinter.