What lies between grey and white in the brain

 Traditionally, neuroscience regards the brain as being made up of two basic tissue types. Billions of neurons make up the grey matter, forming a thin layer on the brain's surface. These neuronal cells are interlinked in a mindboggling network by hundreds of millions of white matter connections, running in bundles, deeper in the brain. Until very recently, not much was known about the interface between the white and grey matter -- the so-called superficial white matter -- because methods were lacking to study it in living human brains. Yet, previous investigations had suggested the region to be implicated in devastating conditions such as Alzheimer's disease and autism. Now a multidisciplinary team led by Nikolaus Weiskopf from the Max Planck Institute for Human Cognitive and Brain Sciences has succeeded in making the superficial white matter visible in the living human brain.

"We demonstrated that the superficial white matter contains a lot of iron. It is known that iron is necessary for the process of myelination," explains Evgeniya Kirilina, first author of the study published in Science Advances. Myelin is what makes the white matter white. It's the fatty coating of nerve cell axons that speeds up transmission of information through the brain. The myelination process can occur throughout the lifespan but is predominant during development. In fact, the largest concentration of iron the researchers found was in the superficial white matter in regions of the frontal cortex, which happens to be the slowest developing structure in the human brain. Incredibly, the human frontal cortex is not fully myelinated until the forth decade of life.

The key to the new method is MRI (Magnetic Resonance Imaging) but at very high field strength. While typical clinical MRI scanners work at 1.5 or 3 Tesla, in terms of the strength of the magnetic field, the Max Planck Institute for Human Cognitive and Brain Sciences houses a powerful 7 Tesla scanner. This, in combination with advanced biophysical model, allowed the team to create very high resolution maps of the white-grey matter border across the entire living brain. The accuracy of their submillimetre maps was assessed against classic and advanced histological methods involving physical dissection and analysis of post mortem brains.

The new method promises many further insights into the organisation of the interface between white and grey matter. Evgeniya Kirilina adds, "We hope the method can be used to increase our understanding of brain development as well as pathological conditions involving the superficial white matter."

From Science Daily

A billion tiny pendulums could detect the universe's missing mass

 

Foucault's pendulum

Researchers at the National Institute of Standards and Technology (NIST) and their colleagues have proposed a novel method for finding dark matter, the cosmos' mystery material that has eluded detection for decades. Dark matter makes up about 27% of the universe; ordinary matter, such as the stuff that builds stars and planets, accounts for just 5% of the cosmos. (A mysterious entity called dark energy accounts for the other 68%.)

According to cosmologists, all the visible material in the universe is merely floating in a vast sea of dark matter -- particles that are invisible but nonetheless have mass and exert a gravitational force. Dark matter's gravity would provide the missing glue that keeps galaxies from falling apart and account for how matter clumped together to form the universe's rich galactic tapestry.

The proposed experiment, in which a billion millimeter-sized pendulums would act as dark matter sensors, would be the first to hunt for dark matter solely through its gravitational interaction with visible matter. The experiment would be one of the few to search for dark matter particles with a mass as great as that of a grain of salt, a scale rarely explored and never studied by sensors capable of recording tiny gravitational forces.

Previous experiments have sought dark matter by looking for nongravitational signs of interactions between the invisible particles and certain kinds of ordinary matter. That's been the case for searches for a hypothetical type of dark matter called the WIMP (weakly interacting massive particles), which was a leading candidate for the unseen material for more than two decades. Physicists looked for evidence that when WIMPs occasionally collide with chemical substances in a detector, they emit light or kick out electric charge.

Researchers hunting for WIMPs in this way have either come up empty-handed or garnered inconclusive results; the particles are too light (theorized to range in mass between that of an electron and a proton) to detect through their gravitational tug.

With the search for WIMPs seemingly on its last legs, researchers at NIST and their colleagues are now considering a more direct method to look for dark matter particles that have a heftier mass and therefore wield a gravitational force large enough to be detected.

"Our proposal relies purely on the gravitational coupling, the only coupling we know for sure that exists between dark matter and ordinary luminous matter," said study co-author Daniel Carney, a theoretical physicist jointly affiliated with NIST, the Joint Quantum Institute (JQI) and the Joint Center for Quantum Information and Computer Science (QuICS) at the University of Maryland in College Park, and the Fermi National Accelerator Laboratory.

The researchers, who also include Jacob Taylor of NIST, JQI and QuICS; Sohitri Ghosh of JQI and QuICS; and Gordan Krnjaic of the Fermi National Accelerator Laboratory, calculate that their method can search for dark matter particles with a minimum mass about half that of a grain of salt, or about a billion billion times the mass of a proton. The scientists report their findings today in Physical Review D.

Because the only unknown in the experiment is the mass of the dark matter particle, not how it couples to ordinary matter, "if someone builds the experiment we suggest, they either find dark matter or rule out all dark matter candidates over a wide range of possible masses," said Carney. The experiment would be sensitive to particles ranging from about 1/5,000 of a milligram to a few milligrams.

That mass scale is particularly interesting because it covers the so-called Planck mass, a quantity of mass determined solely by three fundamental constants of nature and equivalent to about 1/5,000 of a gram.

Carney, Taylor and their colleagues propose two schemes for their gravitational dark matter experiment. Both involve tiny, millimeter-size mechanical devices acting as exquisitely sensitive gravitational detectors. The sensors would be cooled to temperatures just above absolute zero to minimize heat-related electrical noise and shielded from cosmic rays and other sources of radioactivity. In one scenario, a myriad of highly sensitive pendulums would each deflect slightly in response to the tug of a passing dark matter particle.

Similar devices (with much larger dimensions) have already been employed in the recent Nobel-prize-winning detection of gravitational waves, ripples in the fabric of space-time predicted by Einstein's theory of gravity. Carefully suspended mirrors, which act like pendulums, move less than the length of an atom in response to a passing gravitational wave.

In another strategy, the researchers propose using spheres levitated by a magnetic field or beads levitated by laser light. In this scheme, the levitation is switched off as the experiment begins, so that the spheres or beads are in free fall. The gravity of a passing dark matter particle would ever so slightly disturb the path of the free-falling objects.

"We are using the motion of objects as our signal," said Taylor. "This is different from essentially every particle physics detector out there."

The researchers calculate that an array of about a billion tiny mechanical sensors distributed over a cubic meter is required to differentiate a true dark matter particle from an ordinary particle or spurious random electrical signals or "noise" triggering a false alarm in the sensors. Ordinary subatomic particles such as neutrons (interacting through a nongravitational force) would stop dead in a single detector. In contrast, scientists expect a dark matter particle, whizzing past the array like a miniature asteroid, would gravitationally jiggle every detector in its path, one after the other.

Noise would cause individual detectors to move randomly and independently rather than sequentially, as a dark matter particle would. As a bonus, the coordinated motion of the billion detectors would reveal the direction the dark matter particle was headed as it zoomed through the array.

To fabricate so many tiny sensors, the team suggests that researchers may want to borrow techniques that the smartphone and automotive industries already use to produce large numbers of mechanical detectors.

Thanks to the sensitivity of the individual detectors, researchers employing the technology needn't confine themselves to the dark side. A smaller-scale version of the same experiment could detect the weak forces from distant seismic waves as well as that from the passage of ordinary subatomic particles, such as neutrinos and single, low-energy photons (particles of light).

The smaller-scale experiment could even hunt for dark matter particles -- if they impart a large enough kick to the detectors through a nongravitational force, as some models predict, Carney said.

"We are setting the ambitious target of building a gravitational dark matter detector, but the R&D needed to achieve that would open the door for many other detection and metrology measurements," said Carney.

Read more at Science Daily

Ground-breaking discovery finally proves rain really can move mountains

 

Paro Taktsang temple complex in Bhutan

A pioneering technique which captures precisely how mountains bend to the will of raindrops has helped to solve a long-standing scientific enigma.

The dramatic effect rainfall has on the evolution of mountainous landscapes is widely debated among geologists, but new research led by the University of Bristol and published today in Science Advances, clearly calculates its impact, furthering our understanding of how peaks and valleys have developed over millions of years.

Its findings, which focused on the mightiest of mountain ranges -- the Himalaya -- also pave the way for forecasting the possible impact of climate change on landscapes and, in turn, human life.

Lead author Dr Byron Adams, Royal Society Dorothy Hodgkin Fellow at the university's Cabot Institute for the Environment, said: "It may seem intuitive that more rain can shape mountains by making rivers cut down into rocks faster. But scientists have also believed rain can erode a landscape quickly enough to essentially 'suck' the rocks out of the Earth, effectively pulling mountains up very quickly.

"Both these theories have been debated for decades because the measurements required to prove them are so painstakingly complicated. That's what makes this discovery such an exciting breakthrough, as it strongly supports the notion that atmospheric and solid earth processes are intimately connected."

While there is no shortage of scientific models aiming to explain how the Earth works, the greater challenge can be making enough good observations to test which are most accurate.

The study was based in the central and eastern Himalaya of Bhutan and Nepal, because this region of the world has become one of the most sampled landscapes for erosion rate studies. Dr Adams, together with collaborators from Arizona State University (ASU) and Louisiana State University, used cosmic clocks within sand grains to measure the speed at which rivers erode the rocks beneath them.

"When a cosmic particle from outer space reaches Earth, it is likely to hit sand grains on hillslopes as they are transported toward rivers. When this happens, some atoms within each grain of sand can transform into a rare element. By counting how many atoms of this element are present in a bag of sand, we can calculate how long the sand has been there, and therefore how quickly the landscape has been eroding," Dr Adams said.

"Once we have erosion rates from all over the mountain range, we can compare them with variations in river steepness and rainfall. However, such a comparison is hugely problematic because each data point is very difficult to produce and the statistical interpretation of all the data together is complicated."

Dr Adams overcame this challenge by combining regression techniques with numerical models of how rivers erode.

"We tested a wide variety of numerical models to reproduce the observed erosion rate pattern across Bhutan and Nepal. Ultimately only one model was able to accurately predict the measured erosion rates," Dr Adams said.

"This model allows us for the first time to quantify how rainfall affects erosion rates in rugged terrain."

Research collaborator Professor Kelin Whipple, Professor of Geology at ASU, said: "Our findings show how critical it is to account for rainfall when assessing patterns of tectonic activity using topography, and also provide an essential step forward in addressing how much the slip rate on tectonic faults may be controlled by climate-driven erosion at the surface."

The study findings also carry important implications for land use management, infrastructure maintenance, and hazards in the Himalaya.

In the Himalaya, there is the ever-present risk that high erosion rates can drastically increase sedimentation behind dams, jeopardising critical hydropower projects. The findings also suggest greater rainfall can undermine hillslopes, increasing the risk of debris flows or landslides, some of which may be large enough to dam the river creating a new hazard -- lake outburst floods.

Dr Adams added: "Our data and analysis provides an effective tool for estimating patterns of erosion in mountainous landscapes such as the Himalaya, and thus, can provide invaluable insight into the hazards that influence the hundreds of millions of people who live within and at the foot of these mountains."

The research was funded by the Royal Society, the UK Natural Environmental Research Council (NERC), and the National Science Foundation (NSF) of the US.

Building on this important research, Dr Adams is currently exploring how landscapes respond after large volcanic eruptions.

"This new frontier of landscape evolution modelling is also shedding new light on volcanic processes. With our cutting-edge techniques to measure erosion rates and rock properties, we will be able to better understand how rivers and volcanoes have influenced each other in the past," Dr Adams said.

Read more at Science Daily

Star clusters are only the tip of the iceberg

 Star clusters have been part of the Imaginarium of human civilization for millennia. The brightest star clusters to Earth, like the Pleiades, are readily visible to the naked eye. A team around astronomer has now revealed the existence of massive stellar halos, termed coronae, surrounding local star clusters.

"Clusters form big families of stars that can stay together for large parts of their lifetime. Today, we know of roughly a few thousand star clusters in the Milky Way, but we only recognize them because of their prominent appearance as rich and tight groups of stars. Given enough time, stars tend to leave their cradle and find themselves surrounded by countless strangers, thereby becoming indistinguishable from their neighbours and hard to identify" says Stefan Meingast, lead author of the paper published in Astronomy & Astrophysics. "Our Sun is thought to have formed in a star cluster but has left its siblings behind a long time ago" he adds.

Thanks to the ESA Gaia spacecraft's precise measurements, astronomers at the University of Vienna have now discovered that what we call a star cluster is only the tip of the iceberg of a much larger and often distinctly elongated distribution of stars.

"Our measurements reveal the vast numbers of sibling stars surrounding the well-known cores of the star clusters for the first time. It appears that star clusters are enclosed in rich halos, or coronae, more than 10 times as large as the original cluster, reaching far beyond our previous guesses. The tight groups of stars we see in the night sky are just a part of a much larger entity" says Alena Rottensteiner, co-author and master student at the University of Vienna. "There is plenty of work ahead revising what we thought were basic properties of star clusters, and trying to understand the origin of the newfound coronae."

To find the lost star siblings, the research team developed a new method that uses machine learning to trace groups of stars which were born together and move jointly across the sky. The team analyzed 10 star clusters and identified thousands of siblings far away from the center of the compact clusters, yet clearly belonging to the same family. An explanation for the origin of these coronae remains uncertain, yet the team is confident that their findings will redefine star clusters and aid our understanding of their history and evolution across cosmic time.

Read more at Science Daily

Glitter litter could be damaging rivers

 New research indicates that glitter could be causing ecological damage to our rivers and lakes.

The study, led by Dr Dannielle Green of Anglia Ruskin University (ARU) and published in the Journal of Hazardous Materials, is the first to examine the impact of glitter on freshwater habitats.

The research found that after 36 days, the presence of glitter halved the root length of common duckweed (Lemna minor), while levels of chlorophyll in the water were three times lower than in control conditions, indicating reduced levels of phytoplankton, or microalgae.

Glitter is used in a variety of decorative ways, including on clothing, in arts and crafts, and in cosmetics and body paint. Traditional glitter is a form of microplastic consisting of a plastic core made of polyester PET film, which is coated with aluminium and then covered with another thin plastic layer.

Along with other forms of single use microplastics, such as microbeads, there have been efforts to phase out PET glitter with the introduction of more biodegradable alternatives.

One version has a core of modified regenerated cellulose (MRC), sourced mainly from eucalyptus trees, but this is still coated with aluminium for reflectivity and then topped with a thin plastic layer. Another form is mica glitter, which is increasingly used in cosmetics.

However, this new study found that the effects of MRC and mica glitters on root length and chlorophyll levels were almost identical to those of traditional glitter.

The only significant difference was a two-fold increase in the abundance of New Zealand mud snails (Potamopyrgus antipodarum) in water containing the biodegradable MRC glitter. These snails, commonly found in polluted waters, are an invasive species in the UK and an increase in numbers has the potential to disrupt ecosystems, as they can outcompete native species.

Dr Dannielle Green, Senior Lecturer in Biology at Anglia Ruskin University (ARU), said: "Many of the microplastics found in our rivers and oceans have taken years to form, as larger pieces of plastic are broken down over time, However, glitter is a ready-made microplastic that is commonly found in our homes and, particularly through cosmetics, is washed off in our sinks and into the water system.

"Our study is the first to look at the effects of glitter in a freshwater environment and we found that both conventional and alternative glitters can have a serious ecological impact on aquatic ecosystems within a short period of time.

"All types, including so-called biodegradable glitter, have a negative effect on important primary producers which are the base of the food web, while glitter with a biodegradable cellulose core has an additional impact of encouraging the growth of an invasive species.

Read more at Science Daily

Breakthrough blood test developed for brain tumors

 Genetic mutations that promote the growth of the most common type of adult brain tumors can be accurately detected and monitored in blood samples using an enhanced form of liquid biopsy developed by researchers at Massachusetts General Hospital (MGH).

Comparing blood samples from patients with gliomas with tumor biopsy tissues from the same patients, Leonora Balaj, PhD, Bob S. Carter, MD, and other MGH investigators in the Department of Neurosurgery found that a novel digital droplet polymerase chain reaction (ddPCR) blood test they pioneered could accurately detect and monitor over time two mutations of the gene TERT. The mutations, labeled C228T and C250T, are known to promote cancer growth and are present in more than 60 percent of all gliomas, and in 80 percent of all high-grade gliomas, the most aggressive and life-threatening type.

Their discovery, which has the potential to substantially improve the diagnosis and monitoring of gliomas, is reported in the journal Clinical Cancer Research.

Gliomas are tumors of glia, central and peripheral nervous system cells that support and protect neurons, the cells that transmit electrical impulses.

Liquid biopsy is a method for detecting cancer by looking for fragments of tumor DNA that circulate in blood. The technique has been shown to be sensitive at detecting the presence of some forms of cancer, but brain tumors have until now posed a formidable barrier.

"Liquid biopsy is particularly challenging in brain tumors because mutant DNA is shed into the bloodstream at much lower level than any other types of tumors," Balaj says.

"By 'supercharging' our ddPCR assay with novel technical improvements, we showed for the first time that the most prevalent mutation in malignant gliomas can be detected in blood, opening a new landscape for detection and monitoring of the tumors," she says.

The researchers first tested the performance of the ddPCR assay in tumor tissue and found that the results were in perfect agreement with the results from an independently performed clinical laboratory assessment of TERT mutations in the tumor specimens.

They then looked at samples of blood plasma matched to patient tumors and found that the ddPCR assay could detect TERT mutations both in samples from MGH as well as from similarly matched plasma and tumor samples from collaborators at other institutions.

The ddPCR assay has an overall sensitivity (ability to detect the presence of a glioma) of 62.5 percent, which is a tenfold improvement over any prior assay for TERT mutations in the blood for brain tumors, compared to the standard of tissue-based detection of TERT mutations.

The test is easy to use, quick, and low cost, and could be performed in most laboratories, Balaj says. Importantly, the test can also be used to follow the course of disease. "We envision the future integration of tests like this one into the clinical care of our patients with brain tumors," says Carter, chief of Neurosurgery and co-director of the MGH Brain Tumor Center. "For example, if a patient has a suspected mass on MRI scanning, we can take a blood sample before the surgery and assess the presence of the tumor signature in the blood, and then use this signature as a baseline to monitor as the patient later receives treatment, both to gauge response to the treatment and gain early insight into any potential recurrence."

Read more at Science Daily

Will the COVID-19 virus become endemic?

 A new article by Columbia Mailman School researchers Jeffrey Shaman and Marta Galanti explores the potential for the COVID-19 virus to become endemic, a regular feature producing recurring outbreaks in humans. They identify crucial contributing factors, including the risk for reinfection, vaccine availability and efficacy, as well as potential seasonality and interactions with other viral infections that may modulate the transmission of the virus. The article appears in the journal Science.

Shaman is a professor of environmental health sciences and director of the Columbia Mailman School Climate and Health program and a leading authority in modeling infectious disease outbreaks like SARS-CoV-2 and influenza. He was among the first to recognize the importance of asymptomatic spread and the effectiveness of lockdown measures and published highly cited estimations of the hypothetic lives saved had lockdown occurred sooner. He and Galanti, a post-doctoral research scientist in Shaman's research group, also published research finding reinfections with endemic coronaviruses are not uncommon, even within a year of prior infection.

The new paper explores one potential scenario in which immunity to SARS-CoV-2, either through infection or a vaccine, diminishes within a year -- a rate similar to that seen for the endemic betacoronavirus that causes mild respiratory illness. The result would be yearly outbreaks of COVID-19. On the other hand, if immunity to SARS-CoV-2 was longer, perhaps through protection provided by immune response to infection with other endemic coronaviruses, we might experience what would initially appear to be an elimination of COVID-19 followed by a resurgence after a few years. Other contributing factors include the availability and effectiveness of a vaccine and the innate seasonality of the virus.

"Should reinfection prove commonplace, and barring a highly effective vaccine delivered to most of the world's population, SARS-CoV-2 will likely settle into a pattern of endemicity," the authors write. "Whether reinfections will be commonplace, how often they will occur, how contagious re-infected individuals will be, and whether the risk of severe clinical outcomes changes with subsequent infection remain to be understood."

Reinfection

Among those who have been infected with COVID-19, serological studies indicate that most infections, regardless of severity, induce development of some SARS-CoV-2-specific antibodies. Yet it remains unclear whether those antibodies are themselves sufficient to provide long-term "sterilizing immunity" to prevent reinfection. For many viruses, insufficient immune response, waning immunity, or mutations that allow it to "escape" immune detection can undermine or circumvent immunity and allow subsequent reinfection, although a prior infection may provide partial immunity and reduce symptom severity.

Co-Infection

Immune response to SARS-CoV-2 may be affected by whether or not someone is currently or was recently infected with another virus. Many studies prior to the pandemic show that infection with one virus can provide short-term protection -- about a week -- against a second infection. Other studies confirm that simultaneous respiratory virus infections are not associated with increased disease severity. While some SARS-CoV-2 coinfections have been documented, including co-infections with influenza and respiratory syncytial virus, there is insufficient data to draw conclusions. At the population level, a significant seasonal influenza outbreak could strain hospitals already dealing with COVID-19.

Read more at Science Daily

Scientists shed new light on viruses' role in coral bleaching

 Scientists at Oregon State University have shown that viral infection is involved in coral bleaching -- the breakdown of the symbiotic relationship between corals and the algae they rely on for energy.

Funded by the National Science Foundation, the research is important because understanding the factors behind coral health is crucial to efforts to save the Earth's embattled reefs -- between 2014 and 2017 alone, more than 75% experienced bleaching-level heat stress, and 30% suffered mortality-level stress.

The planet's largest and most significant structures of biological origin, coral reefs are found in less than 1% of the ocean but are home to nearly one-quarter of all known marine species. Reefs also help regulate the sea's carbon dioxide levels and are a vital hunting ground that scientists use in the search for new medicines.

Since their first appearance 425 million years ago, corals have branched into more than 1,500 species. A complex composition of dinoflagellates -- including the algae symbiont -- fungi, bacteria, archaea and viruses make up the coral microbiome, and shifts in microbiome composition are connected to changes in coral health.

The algae the corals need can be stressed by warming oceans to the point of dysbiosis -- a collapse of the host-symbiont partnership.

To better understand how viruses contribute to making corals healthy or unhealthy, Oregon State Ph.D. candidate Adriana Messyasz and microbiology researcher Rebecca Vega Thurber of the OSU College of Science led a project that compared the viral metagenomes of coral colony pairs during a minor 2016 bleaching event in Mo'orea, French Polynesia.

Also known as environmental genomics, metagenomics refers to studying genetic material recovered directly from environmental samples, in this case samples taken from a coral reef.

For this study, scientists collected bleached and non-bleached pairs of corals to determine if the mixes of viruses on them were similar or different. The bleached and non-bleached corals shared nearly identical environmental conditions.

"After analyzing the viral metagenomes of each pair, we found that bleached corals had a higher abundance of eukaryotic viral sequences, and non-bleached corals had a higher abundance of bacteriophage sequences," Messyasz said. "This gave us the first quantitative evidence of a shift in viral assemblages between coral bleaching states."

Bacteriophage viruses infect and replicate within bacteria. Eukaryotic viruses infect non-bacterial organisms like animals.

In addition to having a greater presence of eukaryotic viruses in general, bleached corals displayed an abundance of what are called giant viruses. Known scientifically as nucleocytoplasmic large DNA viruses, or NCLDV, they are complex, double-stranded DNA viruses that can be parasitic to organisms ranging from the single-celled to large animals, including humans.

"Giant viruses have been implicated in coral bleaching," Messyasz said. "We were able to generate the first draft genome of a giant virus that might be a factor in bleaching."

The researchers used an electron microscope to identify multiple viral particle types, all reminiscent of medium- to large-sized NCLDV, she said.

"Based on what we saw under the microscope and our taxonomic annotations of viral metagenome sequences, we think the draft genome represents a novel, phylogenetically distinct member of the NCLDVs," Messyasz said. "Its closest sequenced relative is a marine flagellate-associated virus."

Read more at Science Daily

The mountains of Pluto are snowcapped, but not for the same reasons as on Earth

 In 2015, the New Horizons space probe discovered spectacular snowcapped mountains on Pluto, which are strikingly similar to mountains on Earth. Such a landscape had never before been observed elsewhere in the Solar System. However, as atmospheric temperatures on our planet decrease at altitude, on Pluto they heat up at altitude as a result of solar radiation.

So where does this ice come from? An international team led by CNRS scientists conducted this exploration. They first determined that the "snow" on Pluto's mountains actually consists of frozen methane, with traces of this gas being present in Pluto's atmosphere, just like water vapour on Earth.

Then, to understand how the same landscape could be produced in such different conditions, they used a climate model for the dwarf planet, which revealed that due to its particular dynamics, Pluto's atmosphere is rich in gaseous methane at altitudes. As a result, it is only at the peaks of mountains high enough to reach this enriched zone that the air contains enough methane for it to condense.

At lower altitudes the air is too low in methane for ice to form.

This research, published in Nature Communications, could also explain why the thick glaciers consisting of methane observed elsewhere on Pluto bristle with spectacular craggy ridges, unlike Earth's flat glaciers, which consist of water.

From Science Daily

Even minimal physical activity measurably boosts health

 More than 5 million people around the world die from causes associated with a lack of physical activity. Two research teams at UC San Diego School of Medicine sought to understand sedentary lifestyles, with one study finding that even light physical activity, including just standing, can benefit health, and the other that Americans are still sitting too much.

Stand up, your life may depend on it

It is well-documented that exercise and other moderate-to-vigorous physical activity (MVPA) reduces the risk of many age-related chronic diseases, such as heart disease, type 2 diabetes, numerous cancers, Alzheimer's disease and dementia. However, in the study published October 12, 2020 in Journals of Gerontology: Medical Sciences, researchers found that just standing still was associated with lower risk for mortality.

Led by Andrea LaCroix, PhD, chief of epidemiology at UC San Diego School of Medicine, the research team observed activity levels of nearly 6,000 American women, ages 63 to 97, in partnership with the Women's Health Initiative. Participants wore a research-grade accelerometer for seven days to get accurate measures of how much time they spent sitting, standing still or moving.

Participants who spent the most time standing had a 37 percent lower risk of death when compared to the group who didn't stand up as often. While the highest group was standing still almost 90 minutes per day, a lower risk of death was observed by standing still for as little as 30 minutes per day. The positive effects of standing were even stronger when participants were standing and moving around at the same time.

"Avoiding prolonged sedentary time and engaging in regular physical activity are key strategies for older Americans to improve their prospects for healthy aging," said first author Purva Jain, a doctoral candidate and research fellow. "Specifically low-intensity physical activities, such as standing, are important to study due to their feasibility and safety. During our research, we found that simply spending more time on your feet could have important health benefits, such as a decreased risk of mortality."

Adults in the United States aged 65 and older struggle to meet physical activity guidelines, which generally call for 150 minutes of activity per week. According to the researchers, many Americans spend up to 11 hours a day sitting. Women are specifically at an increased risk of having or developing health concerns associated with inactivity.

"Standing is a feasible approach to interrupt long periods of time sitting that takes place throughout the day," said John Bellettiere, PhD, professor of epidemiology at UC San Diego School of Medicine. "We find this most beneficial for older adults who may not be able to partake in moderate-to-vigorous activities any more, but can still follow a healthy aging lifestyle safely just by replacing sitting with standing up more."

"This is the first study of its kind where we were able to decipher between the benefits of standing still versus standing and moving around," said senior author Andrea LaCroix, PhD, "In doing so, we were able to provide rigorous evidence that even standing still results in positive health benefits."

Modern technology and a sedentary life

In another study, published October 12, 2020 in BMJ Open Sport & Exercise Medicine, researchers with UC San Diego School of Medicine used physical activity data collected as part of a survey of farmers in rural Malawi, whose lives are minimally affected by technology, and compared it to lifestyles of Americans.

With this comparison, the team sought to investigate the potential impact of technology-dominated lifestyles on sedentary time and physical activity.

Their findings showed substantially higher levels of activity amongst the Malawi population versus participants in the United States. Specifically, Americans spend nearly two more hours of sedentary time each day compared to Malawians.

"Being able to compare our current activity levels in the United States to the lifestyle of famers in Malawi really puts an exclamation point on how inactive we are," said first author Michael Pratt, MD, director of the Institute for Public Health at UC San Diego. "We evolved to be active beings and we have left that behind for the luxury of certain modern advancements."

The study was conducted in Malawi, a country in Southeast Africa, where farmers in the Zomba and Ntcheu districts were recruited. Nearly all of the sampled farmers lacked electricity at home and did not own motorized vehicles. Conversely, computers, cell phones, TVs and cars dominate the daily lives of many Americans, resulting in increased sedentary time and less need for physical activity.

To quantify the difference in activity levels in these two samples with contrasting lifestyles, researchers asked 414 farmers in Malawi, ages 15 to 85, to wear an accelerometer every day for seven days. The data were then compared to a sample of 3,258 Americans in the same age range measured in previous studies for the same amount of time. Levels of MVPA and light activity in adults in Malawi were substantially higher and sedentary time were lower than those observed in the United States' sample. Researchers used near-identical data collection, scoring and analyses to make their conclusions.

The Malawian farmers met current physical activity guidelines 94 percent of the time, compared to only 55 percent of the United States sample. However, the results may have a different meaning in Malawi where hard work in predominantly subsistence and non-mechanized agriculture on family farms is essential for household food security.

Read more at Science Daily