tag:blogger.com,1999:blog-51047895948959759242024-03-29T04:29:25.331+01:00A Magical JourneyThe Magic Of Reality (est. 2010)Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.comBlogger16265125tag:blogger.com,1999:blog-5104789594895975924.post-64059894599840767152024-03-28T21:33:00.023+01:002024-03-28T21:33:00.127+01:00Astronomers conduct first search for forming planets with new space telescope<p>Planets form in disks of dust and gas called protoplanetary disks that whirl around a central protostar during its final assembly.<br /><br />Although several dozens of such disks have been imaged, just two planets have been caught in the act of forming so far. Now, astronomers are aiming the powerful instruments aboard the James Webb Space Telescope at protoplanetary disks to try to find early clues about the ways in which planets form, and how these planets influence their natal disk.<br /><br />A trio of studies led by the University of Michigan, University of Arizona and University of Victoria combined JWST's images with prior observations made by the Hubble Space Telescope and the Atacama Large Millimeter Array, or ALMA, in Chile. Based on the ancillary observations, the team used JWST to observe protoplanetary disks HL Tau, SAO 206462 and MWC 758 in hopes of detecting any planets that might be forming.<br /><br />In the papers, published in The Astronomical Journal, the researchers pieced together previously unseen interactions between the planet-forming disk and the envelope of gas and dust surrounding the young stars at the center of the protoplanetary disks.<br /><br /><b>To catch a planet</b><br /><br />The U-M study, led by U-M astronomer Gabriele Cugno, aimed JWST at a disk surrounding a protostar called SAO 206462. There, the researchers potentially found a planet candidate in the act of forming in a protoplanetary disk -- but it wasn't the planet they expected to find.<br /><br />"Several simulations suggest that the planet should be within the disk, massive, large, hot, and bright. But we didn't find it. This means that either the planet is much colder than we think, or it may be obscured by some material that prevents us from seeing it," said Cugno, also a co-author on all three papers. "What we have found is a different planet candidate, but we cannot tell with 100% certainty whether it's a planet or a faint background star or galaxy contaminating our image. Future observations will help us understand exactly what we are looking at."<br /><br />Astronomers have observed the disk in the past, notably with the Hubble Space Telescope, the Subaru Telescope, the Very Large Telescope and ALMA. These observations show a disk composed of two strong spirals, which are likely launched by a forming planet. The planet the U-M team expected to find is a type called a gas giant, planets composed mainly of hydrogen and helium, similar to Jupiter in our own solar system.<br /><br />"The problem is, whatever we're trying to detect is hundreds of thousands, if not millions of times fainter than the star," Cugno said. "That's like trying to detect a little light bulb next to a lighthouse."<br /><br />To peer more closely into the disk, the team used an instrument on JWST called NIRCam. NIRCam detects infrared light, and the astronomers used the instrument employing a technique called angular differential imaging. This technique can be used to detect both the thermal radiation of the planet, as the team has done to detect the planet candidate, and specific emission lines associated with material falling onto the planet and hitting its surface with high velocity.<br /><br />"When material falls onto the planet, it shocks at the surface and gives off an emission line at specific wavelengths," Cugno said. "We use a set of narrow-band filters to try to detect this accretion. This has been done before from the ground at optical wavelengths, but this is the first time it's been done in the infrared with JWST."<br /><br /><b>Imaging the 'raw material' of planets</b><br /><br />The University of Victoria paper, led by astronomy student Camryn Mullin, describes images of the disk surrounding the young star HL Tau.<br /><br />"HL Tau is the youngest system in our survey, and still surrounded by a dense inflow of dust and gas falling onto the disk," said Mullin, a co-author of all three studies. "We were amazed by the level of detail with which we could see this surrounding material with JWST, but unfortunately, it obscures any signals from potential planets. "<br /><br />HL Tau's disk is known for having several solar-system scale rings and gaps which could harbor planets.<br /><br />"While there is a ton of evidence for ongoing planet formation, HL Tau is too young with too much intervening dust to see the planets directly," said Jarron Leisenring, the principal investigator of the observing campaign searching for forming planets and astronomer at the University of Arizona Steward Observatory. "We have already begun looking at other young systems with known planets to help form a more complete picture."<br /><br />However, to the team's surprise, JWST revealed unexpected details of a different feature: the proto-stellar envelope, which is essentially a dense inflow of dust and gas surrounding the young star that is just beginning to coalesce, according to Leisenring. Under the influence of gravity, material from the interstellar medium falls inward onto the star and the disk, where it serves as the raw material for planets and their precursors.<br /><br />The UArizona study, led by Kevin Wagner, a NASA Hubble/Sagan Fellow at UArizona Steward Observatory, examined the protoplanetary disk of MWC 758. Similar to SAO 206462, previous observations by the UArizona-led team revealed spiral arms forming in the disk, hinting at a massive planet orbiting its host star.<br /><br />While no new planets were detected in the disk during the most recent observations, the sensitivity is groundbreaking, the researchers say, as it allows them to place the most stringent constraints yet on the suspected planets. For one, the results rule out the existence of additional planets in the outer regions of the MWC 758, consistent with a single giant planet driving the spiral arms.<br /><br />"The lack of planets detected in all three systems tells us that the planets causing the gaps and spiral arms either are too close to their host stars or too faint to be seen with JWST," said Wagner, a co-author of all three studies. "If the latter is true, it tells us that they're of relatively low mass, low temperature, enshrouded in dust, or some combination of the three -- as is likely the case in MWC 758."<br /><br /><b>The search for forming planets continues</b><br /><br />Catching planets in the act of forming is important because astronomers can glean information not only about the formation process, but how chemical elements get distributed throughout a planetary system.<br /><br />"Only about 15 percent of stars like the sun have planets like Jupiter. It's really important to understand how they form and evolve, and to refine our theories," said U-M Michael Meyer, U-M astronomer and coauthor of all three studies. "Some astronomers think that these gas giant planets regulate the delivery of water to rocky planets forming in the inner parts of the disks."<br /><br />Knowing how these disks are shaped by gas giants will help astronomers ultimately understand the properties and evolution of protoplanetary disks that later give rise to rocky, Earth-like planets, said Meyer.<br /><br />"Basically in every disk we have observed with high enough resolution and sensitivity, we have seen large structures like gaps, rings and, in the case of SAO 206462, spirals," Cugno said. "Most if not all of these structures can be explained by forming planets interacting with the disk material, but other explanations that do not involve the presence of giant planets exist.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240327154954.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-90379734994926992792024-03-28T21:32:00.018+01:002024-03-28T21:32:00.126+01:00 Land under water: What causes extreme flooding?<p>If rivers overflow their banks, the consequences can be devastating -- just like the catastrophic floods in North Rhine-Westphalia and Rhineland-Palatinate of 2021 showed. In order to limit flood damage and optimise flood risk assessment, we need to better understand what factors can lead to extreme forms of flooding and to what extent. Using methods of explainable machine learning, researchers at the Helmholtz Centre for Environmental Research (UFZ) have shown that floods are more extreme when several factors are involved in their development. The research was published in Science Advances.<br /><br />There are several factors that play an important role in the development of floods: air temperature, soil moisture, snow depth, and the daily precipitation in the days before a flood. In order to better understand how individual factors contribute to flooding, UFZ researchers examined more than 3,500 river basins worldwide and analysed flood events between 1981 and 2020 for each of them. The result: precipitation was the sole determining factor in only around 25% of the almost 125,000 flood events. Soil moisture was the decisive factor in just over 10% of cases, and snow melt and air temperature were the sole factors in only around 3% of cases. In contrast, 51.6% of cases were caused by at least two factors. At around 23%, the combination of precipitation and soil moisture occurs most frequently.<br /><br />However, when analysing the data, the UFZ researchers discovered that three -- or even all four -- factors can be jointly responsible for a flood event. For example, temperature, soil moisture, and snow depth were decisive factors in around 5,000 floods whilst all four factors were decisive in around 1,000 flood events. And not only that: "We also showed that flood events become more extreme when more factors are involved," says Dr Jakob Zscheischler, Head of the UFZ Department "Compound Environmental Risks" and senior author of the article. In the case of one-year floods, 51.6% can be attributed to several factors; in the case of five- and ten-year floods, 70.1% and 71.3% respectively can be attributed to several factors. The more extreme a flood is, the more driving factors there are and the more likely they are to interact in the event generation. This correlation often also applies to individual river basins and is referred to as flood complexity.<br /><br />According to the researchers, river basins in the northern regions of Europe and America as well as in the Alpine region have a low flood complexity. This is because snow melt is the dominant factor for most floods regardless of the flood magnitude. The same applies to the Amazon basin, where the high soil moisture resulting from the rainy season is often a major cause of floods of varying severity. In Germany, the Havel and the Zusam, a tributary of the Danube in Bavaria, are river basins that have a low flood complexity. Regions with river basins that have a high flood complexity primarily include eastern Brazil, the Andes, eastern Australia, the Rocky Mountains up to the US west coast, and the western and central European plains. In Germany, this includes the Moselle and the upper reaches of the Elbe. "River basins in these regions generally have several flooding mechanisms," says Jakob Zscheischler. For example, river basins in the European plains can be affected by flooding caused by the combination of heavy precipitation, active snow melt, and high soil moisture.<br /><br />However, the complexity of flood processes in a river basin also depends on the climate and land surface conditions in the respective river basin. This is because every river basin has its own special features. Among other things, the researchers looked at the climate moisture index, the soil texture, the forest cover, the size of the river basin, and the river gradient. "In drier regions, the mechanisms that lead to flooding tend to be more heterogeneous. For moderate floods, just a few days of heavy rainfall is usually enough. For extreme floods, it needs to rain longer on already moist soils," says lead author Dr Shijie Jiang, who now works at the Max Planck Institute for Biogeochemistry in Jena.<br /><br />The scientists used explainable machine learning for the analysis. "First, we use the potential flood drivers air temperature, soil moisture, and snow depth as well as the weekly precipitation -- each day is considered as an individual driving factor -- to predict the run-off magnitude and thus the size of the flood," explains Zscheischler. The researchers then quantified which variables and combinations of variables contributed to the run-off of a particular flood and to which extent. This approach is referred to as explainable machine learning because it uncovers the predictive relationship between flood drivers and run-off during a flood in the trained model. "With this new methodology, we can quantify how many driving factors and combinations thereof are relevant for the occurrence and intensity of floods," adds Jiang.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240327154857.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-89626014722829467642024-03-28T21:31:00.020+01:002024-03-28T21:31:00.133+01:00 Researchers turn back the clock on cancer cells to offer new treatment paradigm<p>St. Jude Children's Research Hospital scientists reversed an aggressive cancer, reverting malignant cells towards a more normal state. Rhabdoid tumors are an aggressive cancer which is missing a key tumor suppressor protein. Findings showed that with the missing tumor suppressor, deleting or degrading the quality control protein DCAF5 reversed the cancer cell state. These results suggest a new approach to curing cancer -- returning cancerous cells to an earlier, more normal state rather than killing cancer cells with toxic therapies -- may be possible. The results were published today in Nature.<br /><br />"Rather than making a toxic event that kills rhabdoid cancer, we were able to reverse the cancer state by returning the cells toward normal," said senior author Charles W.M. Roberts, MD, PhD, Executive Vice President and St. Jude Comprehensive Cancer Center director. "This approach would be ideal, especially if this paradigm could also be applied to other cancers."<br /><br />"We found a dependency which actually reverses the cancer state," said first author Sandi Radko-Juettner, PhD, a former St. Jude Graduate School of Biomedical Sciences student, now a Research Program Manager for the Hematological Malignancies Program at St. Jude. "Standard cancer therapies work by causing toxicities that also damage healthy cells in the body. Here, it appears that we're instead fixing the problem caused by the loss of a tumor suppressor in this rhabdoid cancer."<br /><br /><b>Drugging the un-targetable</b><br /><br />In many cancers, there is no easily druggable target. Often, these cancers are caused by a missing tumor suppressor protein, so there is nothing to target directly as the protein is missing. Loss of tumor suppressors is much more common than a protein gaining the ability to drive cancer. Consequently, finding a way to intervene therapeutically in these tumors is a high priority. The researchers were looking for a way to treat an aggressive set of cancers caused by the loss of the tumor suppressor protein SMARCB1 when they found a new approach to treatment.<br /><br />The St. Jude group found a little-studied protein, DCAF5, was essential to rhabdoid tumors missing SMARCB1. Initially, they identified DCAF5 as a target, using the Dependency Map (DepMap) portal, a database of cancer cell lines and the genes critical for their growth. DCAF5 was a top dependency in rhabdoid tumors. After the initial finding, the scientists genetically deleted or chemically degraded DCAF5. The cancer cells reverted to a non-cancerous state, persisting even in a long-term mouse model.<br /><br />"We saw a spectacular response," Roberts said. "The tumors melted away."<br /><br /><b>Removing quality control to reverse cancer</b><br /><br />Normally, SMARCB1 is an essential component of a larger chromatin-regulating complex of proteins called the SWI/SNF complex. Unexpectedly, the study found that in the absence of SMARCB1, DCAF5 recognizes SWI/SNF as abnormal and destroys the complex. When DCAF5 degrades them, the researchers showed that SWI/SNF re-forms and maintains its ability to open chromatin and regulate gene expression. While the SWI/SNF activity level in the absence of SMARCB1 was to a lesser extent than usual, it was nonetheless sufficient to reverse the cancer state fully.<br /><br />"DCAF5 is doing a quality control check to ensure that these chromatin machines are built well," Roberts said. "Think of a factory assembling a machine. You need quality checks to examine and find faults and to pull it off the line if it doesn't meet standards. DCAF5 is doing such quality assessments for the assembly of SWI/SNF complexes, telling the cell to get rid of complexes if SMARCB1 is absent."<br /><br />"The mutation of SMARCB1 shuts off gene programs that prevent cancer. By targeting DCAF5, we're turning those gene programs back on," Radko-Juettner said. "We're reversing the cancer state because the cell is becoming more 'normal' when these complexes aren't targeted for destruction by DCAF5."<br /><br /><b>Future therapeutic opportunities to reverse cancer</b><br /><br />"From a therapeutic perspective, our results are fascinating," Radko-Juettner said. "DCAF5 is part of a larger family of DCAF proteins that have been shown to be drug targetable. We showed that when DCAF5 is absent, mice had no discernable health effects, so we could potentially target DCAF5. This can kill the cancer cells but shouldn't affect healthy cells. Targeting DCAF5 thus has the potential to avoid the off-target toxicity of radiation or chemotherapy, making it a promising therapeutic avenue to pursue."<br /><br />Beyond DCAF5, the findings could have implications for other cancers driven by the loss of a tumor suppressor.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240327124810.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-4053301909507441342024-03-28T21:30:00.022+01:002024-03-28T21:30:00.141+01:00Scientists extract genetic secrets from 4,000-year-old teeth to illuminate the impact of changing human diets over the centuries<p>Researchers at Trinity College Dublin have recovered remarkably preserved microbiomes from two teeth dating back 4,000 years, found in an Irish limestone cave. Genetic analyses of these microbiomes reveal major changes in the oral microenvironment from the Bronze Age to today. The teeth both belonged to the same male individual and also provided a snapshot of his oral health.<br /><br />The study, carried out in collaboration with archaeologists from the Atlantic Technological University and University of Edinburgh, was published today in journal Molecular Biology and Evolution. The authors identified several bacteria linked to gum disease and provided the first high-quality ancient genome of Streptococcus mutans, the major culprit behind tooth decay.<br /><br />While S. mutans is very common in modern mouths, it is exceptionally rare in the ancient genomic record. One reason for this may be the acid-producing nature of the species. This acid decays the tooth, but also destroys DNA and stops plaque from fossilising. While most ancient oral microbiomes are retrieved from fossilised plaque, this study targeted the tooth directly.<br /><br />Another reason for the scarcity of S. mutans in ancient mouths may be the lack of favorable habitats for this sugar-loving species. An uptick of dental cavities is seen in the archaeological record after the adoption of cereal agriculture thousands of years ago, but a far more dramatic increase has occurred only in the past few hundred years when sugary foods were introduced to the masses.<br /><br />The sampled teeth were part of a larger skeletal assemblage excavated from Killuragh Cave, County Limerick, by the late Peter Woodman of University College Cork. While other teeth in the cave showed advanced dental decay, no cavities were visible on the sampled teeth. However, one tooth produced an unprecedented amount of S. mutans DNA, a sign of an extreme imbalance in the oral microbial community.<br /><br />"We were very surprised to see such a large abundance of S. mutans in this 4,000-year-old tooth," said Dr Lara Cassidy, an assistant professor in Trinity's School of Genetics and Microbiology, and senior author of the study. "It is a remarkably rare find and suggests this man was at a high risk of developing cavities right before his death."<br /><br />The researchers also found that other streptococcal species were virtually absent from the tooth. This indicates the natural balance of the oral biofilm had been upset -- mutans had outcompeted the other streptococci leading to the pre-disease state.<br /><br />The team also found evidence to support the "disappearing microbiome" hypothesis, which proposes modern microbiomes are less diverse than those of our ancestors. This is cause for concern, as biodiversity loss can impact human health. The two Bronze Age teeth produced highly divergent strains of Tannerella forsythia, a bacteria implicated in gum disease.<br /><br />"These strains from a single ancient mouth were more genetically different from one another than any pair of modern strains in our dataset, despite the modern samples deriving from Europe, Japan and the USA," explained Iseult Jackson, a PhD candidate at Trinity, and first author of the study. "This represents a major loss in diversity and one that we need to understand better."<br /><br />Very few full genomes from oral bacteria have been recovered prior to the Medieval era. By characterising prehistoric diversity, the authors were able to reveal dramatic changes in the oral microenvironment that have happened since.<br /><br />Dr Cassidy added: "Over the last 750 years, a single lineage of T. forsythia has become dominant worldwide. This is the tell-tale sign of natural selection, where one strain rises rapidly in frequency due to some genetic advantage it holds over the others. T. forsythia strains from the industrial era onwards contain many new genes that help the bacteria colonise the mouth and cause disease.<br /><br />"S. mutans has also undergone recent lineage expansions and changes in gene content related to pathogenicity. These coincide with humanity's mass consumption of sugar, although we did find that modern S. mutans populations have remained more diverse, with deep splits in the S. mutans evolutionary tree pre-dating the Killuragh genome."<br /><br />The scientists believe this is driven by differences in the evolutionary mechanisms that shape genome diversity in these species.<br /><br />"S. mutans is very adept at swapping genetic material between strains," said Dr Cassidy. "This means an advantageous innovation can be spread across S. mutans lineages like a new piece of tech. This ability to easily share innovations may explain why this species retains many diverse lineages without one becoming dominant and replacing all the others."</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240327124735.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-57701489200670790452024-03-27T22:03:00.020+01:002024-03-27T22:03:00.140+01:00Sleeping supermassive black holes awakened briefly by shredded stars<p>A new investigation into an obscure class of galaxies known as Compact Symmetric Objects, or CSOs, has revealed that these objects are not entirely what they seem. CSOs are active galaxies that host supermassive black holes at their cores. Out of these monstrous black holes spring two jets traveling in opposite directions at nearly the speed of light. But in comparison to other galaxies that boast fierce jets, these jets do not extend out to great distances -- they are much more compact. For many decades, astronomers suspected that CSOs were simply young and that their jets would eventually travel out to greater distances.<br /><br />Now, reporting in three different papers in The Astrophysical Journal, a Caltech-led team of researchers has concluded that CSOs are not young but rather lead relatively short lives.<br /><br />"These CSOs are not young," explains Anthony (Tony) Readhead, the Robinson Professor of Astronomy, Emeritus, who led the investigation. "You wouldn't call a 12-year-old dog young even though it has lived a shorter life than an adult human. These objects are a distinct species all of their own that live and die out in thousands of years rather than the millions of years that are common in galaxies with bigger jets."<br /><br />In the new studies, the team reviewed literature and past observations of more than 3,000 CSO candidates, verifying 64 as real and identifying an additional 15 CSOs. All these objects had been previously observed by the National Radio Astronomy Observatory's Very Long Baseline Array (VLBA), funded by the National Science Foundation (NSF), and some had been observed by other high-resolution radio telescopes. "The VLBA observations are the most detailed in astronomy, providing images with details equivalent to measuring the width of a human hair at a distance of 100 miles," Readhead says.<br /><br />The team's analysis concludes that CSOs expel jets for 5,000 years or less and then die out. "The CSO jets are very energetic jets but they seem to shut off," says Vikram Ravi, assistant professor of astronomy at Caltech and a co-author of one of the studies. "The jets stop flowing from the source."<br /><br />As for what is fueling the short-lived jets, the scientists believe the cause is a tidal disruption event (TDE), which occurs when a single star wanders too close to a supermassive black hole and is devoured.<br /><br />"We think that a single star gets ripped apart, and then all that energy is channeled into jets along the axis the black hole is spinning around," Readhead says. "The giant black hole starts out invisible to us, and then when it consumes a star, boom! The black hole has fuel, and we can see it."<br /><br />Readhead first suspected that CSOs might be fueled by TDEs back in the 1990s, but he says the idea went largely unnoticed by the scientific community. "The hypothesis was all but forgotten because years went by before observational evidence began to mount for TDEs," he says. At the time of his original hypothesis, only three CSOs had been found.<br /><br />Fast forward to 2020. Readhead, who had paused his studies of CSOs to delve into different problems in radio astronomy, decided it was time to revisit the topic. He gathered some of his colleagues together on Zoom, and they decided to comb through literature and weed out objects that had been misclassified as CSOs. Over the next two years, the team investigated more than 3,000 CSO candidates, narrowing the group down to only dozens that had the criteria to be real CSOs.<br /><br />Ultimately, a picture began to emerge of CSOs as an entirely distinct family with jets that die out much sooner than their gigantic brethren, such as those of the extremely powerful Cygnus A, a galaxy that shoots out extremely powerful jets that glow brightly at radio wavelengths. These jets stretch to distances of about 230,000 light-years in each direction and last tens of millions of years. In contrast, the CSO jets extend to about 1,500 light-years at most and die out by about 5,000 years.<br /><br />According to the astronomers, the CSO jets likely form when a supermassive black hole snacks on not just any star, but a substantial one.<br /><br />"The TDEs we've previously seen only lasted for a few years," Ravi says. "We think that the remarkable TDEs powering CSOs last far longer because the disrupted stars are very large in size, very massive, or both."<br /><br />By analyzing the varied collection of CSO radio images, the researchers say they can trace how the objects age over time, almost like looking at a photo album of a CSO's life to observe how its jets evolve. The younger CSOs have shorter jets that are closer to the black holes, while the older objects have jets that extend further out from their black hole. Though most of the jets die out, the scientists estimate that one in 100 will go onto to become long-lived like those of Cygnus A. In those rare cases, the galaxies are likely merging with other galaxies, a turbulent process that provides a large quantity of fuel.<br /><br />If the discoveries of Readhead and his team are confirmed with additional observations, the CSOs will provide a whole new avenue for studying how massive stars at the centers of galaxies interact with supermassive black holes.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240326170117.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-88733055979057746102024-03-27T22:02:00.015+01:002024-03-27T22:02:00.141+01:00New roadmap to prevent pandemics centers on protecting biodiversity<p>An international team of 25 scientists has proposed a roadmap for how to prevent the next pandemic by conserving natural areas and promoting biodiversity, thereby providing animals with enough food, safe havens and distance to limit contact and the transfer of pathogens to humans.<br /><br />Pandemics begin when disease-harboring animals, such as bats, come in close proximity with people, livestock or other animals and pass on new pathogens.<br /><br />Viruses such as SARS-CoV-2, SARS-CoV-1, Nipah, Hendra and possibly Ebola have all fatally spilled over from bats to humans, sometimes through an intermediate host.<br /><br />"The world is focused on how can we detect and then contain a novel pathogen once it is circulating in humans, rather than how can we prevent that pathogen from entering the human population in the first place," said Raina Plowright, professor in the Department of Public and Ecosystem Health at Cornell University, and first author of the paper, "Ecological Countermeasures to Prevent Pathogen Spillover and Subsequent Pandemics," published in Nature Communications.<br /><br />The pandemic-prevention strategy is based on insights from a pair of 2022 papers that serve as a case study applicable to all animals that potentially carry zoonotic diseases.<br /><br />Those papers -- about how bats can spread fatal Hendra virus to horses and people -- explained that when bats lose their natural habitats and winter food sources, their large populations splinter and they migrate in small groups to agricultural and urban areas.<br /><br />They also become stressed, partly due to inadequate food sources, and they shed more virus in their urine.<br /><br />The virus falls to the ground where grazing horses become infected; horses in turn can then infect people.<br /><br />But when natural habitats can provide adequate food, especially in fallow winter months, the bats return to these habitats, aggregate in large numbers, and stop shedding virus.<br /><br />The roadmap uses this and other case studies to explain the mechanisms linking environmental change and spillover of pathogens from animals to humans, and identifies ecological interventions to disrupt these links and policy frameworks to implement them.<br /><br />Ecological interventions begin by protecting the places where animals eat.<br /><br />"We need to make sure there's always an abundant supply of food available at all times of year, especially when animals are in stressful life history stages like reproduction and migration," Plowright said.<br /><br />Next, it's important to protect where animals may roost or aggregate, as tens of thousands of bats can roost in canopies and caves, so when these areas are disturbed, these populations can splinter, move and shed more virus.<br /><br />Also, cave dwelling bats may not have other caves to move to, in which case they stay put, become more stressed and likely shed more virus.<br /><br />Protecting lands that act as buffers between people and wildlife is also key.<br /><br />"There are trillions of microbes in nature, but we rarely actually get sick, because there are many, many barriers between us and new pathogens," Plowright said.<br /><br />Lastly, for communities who come in contact with animals, it's important to ensure people have the protection that they need to avoid pathogen exposure, Plowright said.<br /><br />The study's authors emphasize the need for an international agency or panel that can assess and synthesize data on pandemic prevention, preparedness and response and collect metrics on intactness of landscapes, ecological integrity and biodiversity.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240326103855.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-56939370614391839612024-03-27T22:01:00.017+01:002024-03-27T22:01:00.156+01:00Beethoven's genes reveal low predisposition for beat synchronization<p>Ludwig van Beethoven, one of the most celebrated musicians in human history, has a rather low genetic predisposition for beat synchronization, according to a Current Biologystudy co-authored by Vanderbilt University Medical Center (VUMC) and theMax Planck Institutes for Empirical Aesthetics in Frankfurt am Main, Germany, and for Psycholinguistics in Nijmegen, the Netherlands.<br /><br />The question of to what extent are exceptional human achievements influenced by genetic factors dates back to the early days of human genetics but seems to be easier to address today as modern molecular methods make it possible to analyze DNA of individuals throughout history.<br /><br />An international team of researchers analyzed Beethoven's DNA to investigate his genetic musical predisposition, an ability closely related to musicality, by using sequences from a 2023 study in which the composer's genetic material was extracted from strands of his hair.<br /><br />"For Beethoven, we used his recently sequenced DNA to calculate a polygenic score as an indicator for his genetic predisposition for beat synchronization," said Tara Henechowicz, B.Mus.Hons, M.A., a current PhD Candidate at the University of Toronto, recent visiting graduate student with the Vanderbilt Human Genetics Program, and the paper's second author.<br /><br />"Interestingly, Beethoven, one of the most celebrated musicians in history, had an unremarkable polygenic score for general musicality compared to population samples from the Karolinska Institute in Sweden and Vanderbilt's BioVU Repository," she said.<br /><br />The authors noted that it would be wrong to conclude from Beethoven's low polygenic score that his musical abilities were unexceptional.<br /><br />"Our aim was to use this as an example of the challenges of making genetic predictions for an individual who lived over 200 years ago," Henechowicz said.<br /><br />"The mismatch between the DNA-based prediction and Beethoven's musical genius provides a valuable teaching moment, because it demonstrates that DNA tests cannot give us a definitive answer about whether a given child will end up being musically gifted."<br /><br />Henechowicz said the study does not discount that DNA contributes to people's musical skills, noting that prior studies have found an average heritability, which is the proportion of individual differences explained by all genetic factors, of 42% for musicality.<br /><br />"In the current era of 'big data' such as Vanderbilt's BioVU repository, we have had the opportunity to look in fine detail at large groups of people to uncover the genetic underpinnings of traits such as rhythm ability or being musically active. The current study and other recent work also suggest that environment plays a key role in musical ability and engagement as well," said co-author Reyna Gordon, PhD, associate professor of Otolaryngology at VUMC and graduate co-advisor to Henechowicz.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240326124553.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-79040768202458998902024-03-27T22:00:00.026+01:002024-03-27T22:00:00.131+01:00Persian plateau unveiled as crucial hub for early human migration out of Africa<p>A new study combining genetic, palaeoecological, and archaeological evidence has unveiled the Persian Plateau as a pivotal geographic location serving as a hub for Homo sapiens during the early stages of their migration out of Africa.<br /><br />This revelation sheds new light on the complex journey of human populations, challenging previous understandings of our species' expansion into Eurasia.<br /><br />The study, published in Nature Communications, highlights a crucial period between approximately 70,000 to 45,000 years ago when human populations did not uniformly spread across Eurasia, leaving a gap in our understanding of their whereabouts during this time frame.<br /><br />Key findings from the research include:<br /><br /></p><ul style="text-align: left;"><li>The Persian plateau as a hub for early human settlement: Using a novel genetic approach combined with palaeoecological modelling, the study revealed the Persian Plateau as the region where from population waves that settled all of Eurasia originated.</li><li>This region emerged as a suitable habitat capable of supporting a larger population compared with other areas in West Asia.</li><li>Genetic resemblance in ancient and modern populations: The genetic component identified in populations from the Persian Plateau underlines its long-lasting differentiation in the area, compatible with the hub nature of the region, and is ancestral to the genetic components already known to have inhabited the Plateau.</li><li>Such a genetic signature was detected thanks to a new approach that disentangles 40,000 years of admixture and other confounding events. This genetic connection underscores the Plateau's significance as a pivotal location for early human settlement and subsequent migrations.</li></ul><p><br />Study co-author Professor Michael Petraglia, Director of Griffith University's Australian Research Centre for Human Evolution, provided a much clearer picture of these early human movements.<br /><br />"Our multidisciplinary study provides a more coherent view of the ancient past, offering insights into the critical period between the Out of Africa expansion and the differentiation of Eurasian populations," Professor Petraglia said.<br /><br />"The Persian Plateau emerges as a key region, underlining the need for further archaeological explorations."<br /><br />First author Leonardo Vallini of the University of Padova, Italy, said: "The discovery elucidates a 20,000 year long portion of the history of Homo sapiens outside of Africa, a timeframe during which we interacted with Neanderthal populations, and sheds light on the relationships between various Eurasian populations, providing crucial clues for understanding the demographic history of our species across Europe, East Asia, and Oceania."</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240325114147.htm" target="_blank">Science Daily</a><br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-8791553231167121062024-03-26T22:03:00.021+01:002024-03-26T22:03:00.158+01:00Tiniest 'starquake' ever detected<p>An orange dwarf star has yielded the tiniest 'starquakes' ever recorded, measured by an international team of scientists.<br /><br />Named Epsilon Indi, the star is the smallest and coolest dwarf star yet observed with solar-like oscillations -- "starquakes" like those shown by the Sun.<br /><br />These oscillations provide indirect glimpses of stellar interiors -- just as earthquakes tell us about Earth's interior -- and so are important sources of information about the makeup of the star.<br /><br />The measurements were taken by an international team, led by the Institute of Astrophysics and Space Sciences in Portugal, and including researchers from the University of Birmingham.<br /><br />The study is published in Astronomy and Astrophysics Letters.<br /><br />The quakes were detected using a technique dubbed asteroseismology, which measures oscillations in stars.<br /><br />Using the ESPRESSO spectrograph, mounted at the European Southern Observatory's (ESO) Very Large Telescope (VLT), the team was able to record the oscillations with unprecedented precision.<br /><br />Lead author Tiago Campante, of the Institute of Astrophysics and Space Sciences at the University of Porto, said: "The extreme precision level of these observations is an outstanding technological achievement. Importantly, this detection conclusively shows that precise asteroseismology is possible down to cool dwarfs with surface temperatures as low as 4200 degrees Celsius, about 1000 degrees cooler than the Sun's surface, effectively opening up a new domain in observational astrophysics."<br /><br />Orange dwarf stars have recently become a focus in the search for habitable planets and extraterrestrial life.<br /><br />Professor Bill Chaplin, Head of the School of Physics & Astronomy at Birmingham, and a member of the team, said: "The mismatch between the predicted and observed sizes of these stars has implications for finding planets around them. If we use the most successful planet-finding technique -- the so-called transit method -- we get the size of the planet relative to the size of the star; if we don't size-up the star correctly, the same will be true of any small planet we have found." The detection of oscillations will help to understand and minimise these discrepancies, and improve the theoretical models of stars.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240326103908.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-43796462419196747752024-03-26T22:02:00.021+01:002024-03-26T22:02:00.132+01:00Climate change will see Australia's soil emit CO2 and add to global warming<p>New Curtin University research has shown the warming climate will turn Australia's soil into a net emitter of carbon dioxide (CO2), unless action is taken.<br /><br />Soil helps to keep the planet cool by absorbing carbon, however as the climate gets warmer its ability to retain carbon decreases -- and in some instances can start to release some carbon back into the air.<br /><br />A global research team -- led by Professor Raphael Viscarra Rossel from Curtin's School of Molecular and Life Sciences -- predicted the changes in the amount of carbon in Australia's soil between now and the year 2100.<br /><br />To do so, the team ran simulations using three different paths for society: an eco-focused 'sustainable' scenario, a 'middle-of-the-road' scenario and another which predicted a continued reliance on 'fossil-fuelled development'.<br /><br />It found Australian soil will be a net emitter and could account for 8.3 per cent of Australia's total current emissions under the 'sustainable' scenario and more than 14 per cent by 2045 under the 'middle-of-the-road' and 'fossil-fuelled' scenarios.<br /><br />By 2100, soil emissions under both scenarios are predicted to account for an even higher proportion of total emissions, but the predictions are more uncertain.<br /><br />While some areas with arable farmland could continue to store carbon, the study found it would not be enough to offset the amounts of carbon lost from the soil in areas which are more sensitive to warmer weather, such as coastal regions and Australia's vast rangelands.<br /><br />Australian soil holds an estimated 28 gigatons of carbon, 70 per cent of which is stored in these rangelands.<br /><br />"Unless farming methods are further improved so farmland soils can continue to store carbon, any gains and benefit will likely decrease by 2045 and worsen in time, if the Earth continues to warm at its current rate," Professor Viscarra Rossel said.<br /><br />"This means Australia's soil could release even more carbon into the air instead of storing it, which will in turn make climate change worse.<br /><br />"If emissions continue at the current rate, the Earth's temperature is expected to reach 2 degrees above pre-industrial temperatures sometime this century, which is predicted to have dire consequences and<br /><br />potentially catastrophic impacts for the planet."<br /><br />Professor Viscarra Rossel said more sustainable pathways and improved management and conservation of soils were essential for Australia to meet its emissions reduction goals.<br /><br />"Ensuring Australia's rangeland soils can maintain their carbon stocks is imperative: capturing and storing additional carbon will require interdisciplinary science, innovation, cultural awareness and effective policies" Professor Viscarra Rossel said.<br /><br />"It will be challenging, given the rangelands' drier and more variable climate, its relatively sparse vegetation and other factors such as bushfires -- however, only a slight change over such large areas will make a positive difference.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240326103845.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-10439360389509961902024-03-26T22:01:00.018+01:002024-03-26T22:01:00.124+01:00Stem cell model offers first glimpse of early human embryonic development<p>It's one of life's most defining moments -- that crucial step in embryonic development, when an indistinct ball of cells rearranges itself into the orderly three-layered structure that sets the stage for all to come. Known as gastrulation, this crucial process unfolds in the third week of human development. "Gastrulation is the origin of our own individualization, the emergence of our axis," says Rockefeller's Ali Brivanlou. "It is the first moment that separates our heads from our behinds."<br /><br />Observing the molecular underpinnings of this pivotal event would go a long way toward helping scientists prevent miscarriages and developmental disorders. But studying human gastrulation has proven both technologically difficult and ethically complicated, and thus current approaches have had limited success in expanding our understanding of early human development. Now Brivanlou and colleagues have demonstrated how a stem cell model system known as a blastoid can allow the study of the nuances of human gastrulation in the presence of pre-implantation extra-embryonic cell types. Their study, published in Stem Cell Reports, describes the scientific and clinical potential of this new platform.<br /><br />"Gastrulation was a tremendous black box. We had never seen ourselves at that stage," Brivanlou says. "This moves us closer to understanding how we begin."<br /><br /><b>A better blastocyst</b><br /><br />Prior to implantation, an embryo is a ball of about 250 cells organized as a blastocyst. This elusive ball of cells was difficult to study directly, so scientists developed blastoids -- stem-cell-based blastocyst models. Blastoids can be cloned, experimentally manipulated, and programmed, allowing scientists to study identical blastoids over and over again.<br /><br />The question was whether blastoids could gastrulate in vitro. Unlike a blastocyst in vivo, which rolls around in the uterus until it attaches to maternal tissue, blastoids were good at modeling the ball of cells from which life emerges, but it remained unclear whether this in vitro model could model later stages of human development. That is, until Brivanlou developed a platform to allow blastoids to attach in vitro, and thereby progress toward gastrulation.<br /><br />"We were then able to see epiblast symmetry breaking, marked by BRA expression, for the first time with the high molecular resolution," says Riccardo De Santis, a research associate in the Brivanlou lab and lead author on the study. "This allowed us to start asking more detailed questions about the earliest moments of life."<br /><br />With this unprecedented clarity, the team directly observed two key moments in gastrulation: the first epiblast symmetry-breaking event and the emergence of the molecular markers of the primitive streak and mesoderm upon in vitro attachment.<br /><br />The primitive streak is a structure that marks the beginning of gastrulation and lays the foundation for the three primary layers of the embryo. One of those layers, the mesoderm, forms during gastrulation and gives rise to muscles, bones, and the circulatory system. The team discovered that, as early as seven days after attachment, they were already able to use molecular markers to detect the earliest signature of a nascent primitive streak and mesodermal cells.<br /><br />To confirm their findings, the team also compared the blastoid results with data from in vitro attached human embryos and demonstrated that blastoids express the same genes in vitro that a regular embryo would at that stage in vivo, a strong demonstration of the power of blastoids as models for human embryonic development. Further highlighting the power of the lab's in vitro attached blastoid system, the team then used it to demonstrate that pathways that regulate the rise of the primitive streak and mesoderm in vivo also regulate blastoids symmetry breaking in vitro -- all with nothing but stem-cell-derived blastoid models.<br /><br />Along the way, the team also demonstrated that gastrulation in vitro can begin at day 12, earlier than once thought. "This will change textbooks," Brivanlou says. "We've contributed to redefining the molecular signature and timing of the onset of gastrulation upon in vitro attachment."<br /><b><br />Therapeutic possibilities</b><br /><br />The results demonstrate that blastoids, when combined with the Brivanlou lab's unique attachment platform, are now capable of conveying insights into early human development that have long been inaccessible. De Santis envisions a future in which blastoid-based research leads to advancements in diagnosing and treating developmental disorders, or offers insights into potential causes of early miscarriages during gastrulation.<br /><br />"Many couples can't have babies because the embryo doesn't attach properly, and many miscarriages occur in the first few weeks of pregnancy," De Santis explains. "We now have a model system that can help us understand the molecular mechanism that defines whether a pregnancy will be successful or not." In the near future, De Santis hopes to combine this method with machine learning to help predict pregnancy outcomes and the trajectories of developmental disorders by observing how model blastoids built with particular genetic makeups fare in vitro.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240323172741.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-6814364921761630642024-03-26T22:00:00.019+01:002024-03-26T22:00:00.251+01:00Common household chemicals pose new threat to brain health, study finds<p>A team of researchers from the Case Western Reserve University School of Medicine has provided fresh insight into the dangers some common household chemicals pose to brain health. They suggest that chemicals found in a wide range of items, from furniture to hair products, may be linked to neurological conditions like multiple sclerosis and autism spectrum disorders.<br /><br />Neurological problems impact millions of people, but only a fraction of cases can be attributed to genetics alone, indicating that unknown environmental factors are important contributors.<br /><br />The new study published today in the journal Nature Neuroscience, discovered that some common home chemicals specifically affect the brain's oligodendrocytes, a specialized cell type that generates the protective insulation around nerve cells.<br /><br />"Loss of oligodendrocytes underlies multiple sclerosis and other neurological diseases," said the study's principal investigator, Paul Tesar, the Dr. Donald and Ruth Weber Goodman Professor of Innovative Therapeutics and director of the Institute for Glial Sciences at the School of Medicine. "We now show that specific chemicals in consumer products can directly harm oligodendrocytes, representing a previously unrecognized risk factor for neurological disease."<br /><br />On the premise that not enough thorough research has been done on the impact of chemicals on brain health, the researchers analyzed over 1,800 chemicals that may be exposed to humans. They identified chemicals that selectively damaged oligodendrocytes belong to two classes: organophosphate flame retardants and quaternary ammonium compounds. Since quaternary ammonium compounds are present in many personal-care products and disinfectants, which are being used more frequently since the COVID-19 pandemic began, humans are regularly exposed to these chemicals. And many electronics and furniture include organophosphate flame retardants.<br /><br />The researchers used cellular and organoid systems in the laboratory to show that quaternary ammonium compounds cause oligodendrocytes to die, while organophosphate flame retardants prevented the maturation of oligodendrocytes.<br /><br />They demonstrated how the same chemicals damage oligodendrocytes in the developing brains of mice. The researchers also linked exposure to one of the chemicals to poor neurological outcomes in children nationally.<br /><br />"We found that oligodendrocytes -- but not other brain cells -- are surprisingly vulnerable to quaternary ammonium compounds and organophosphate flame retardants," said Erin Cohn, lead author and graduate student in the School of Medicine's Medical Scientist Training Program. "Understanding human exposure to these chemicals may help explain a missing link in how some neurological diseases arise."<br /><br />The association between human exposure to these chemicals and effects on brain health requires further investigation, the experts warned. Future research must track the chemical levels in the brains of adults and children to determine the amount and length of exposure needed to cause or worsen disease.<br /><br />"Our findings suggest that more comprehensive scrutiny of the impacts of these common household chemicals on brain health is necessary," Tesar said. "We hope our work will contribute to informed decisions regarding regulatory measures or behavioral interventions to minimize chemical exposure and protect human health."</p><p> Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240325135708.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-30262425776243140192024-03-24T21:32:00.014+01:002024-03-24T21:32:00.141+01:00Quantum tornado provides gateway to understanding black holes<p>Scientists have for the first time created a giant quantum vortex to mimic a black hole in superfluid helium that has allowed them to see in greater detail how analogue black holes behave and interact with their surroundings.<br /><br />Research led by the University of Nottingham, in collaboration with King's College London and Newcastle University, have created a novel experimental platform: a quantum tornado.<br /><br />They have created a giant swirling vortex within superfluid helium that is chilled to the lowest possible temperatures.<br /><br />Through the observation of minute wave dynamics on the superfluid's surface, the research team has shown that these quantum tornados mimic gravitational conditions near rotating black holes.<br /><br />The research has been published today in Nature.<br /><br />Lead author of the paper, Dr Patrik Svancara from the School of Mathematical Sciences at the University of Nottingham explains: "Using superfluid helium has allowed us to study tiny surface waves in greater detail and accuracy than with our previous experiments in water. As the viscosity of superfluid helium is extremely small, we were able to meticulously investigate their interaction with the superfluid tornado and compare the findings with our own theoretical projections."<br /><br />The team constructed a bespoke cryogenic system capable of containing several litres of superfluid helium at temperatures lower than -271 °C. At this temperature liquid helium acquires unusual quantum properties.<br /><br />These properties typically hinder the formation of giant vortices in other quantum fluids like ultracold atomic gases or quantum fluids of light, this system demonstrates how the interface of superfluid helium acts as a stabilizing force for these objects.<br /><br />Dr Svancara continues: "Superfluid helium contains tiny objects called quantum vortices, which tend to spread apart from each other. In our set-up, we've managed to confine tens of thousands of these quanta in a compact object resembling a small tornado, achieving a vortex flow with record-breaking strength in the realm of quantum fluids."<br /><br />Researchers uncovered intriguing parallels between the vortex flow and the gravitational influence of black holes on the surrounding spacetime.<br /><br />This achievement opens new avenues for simulations of finite-temperature quantum field theories within the complex realm of curved spacetimes.<br /><br />Professor Silke Weinfurtner, leading the work in the Black Hole Laboratory where this experiment was developed, highlights the significance of this work: "When we first observed clear signatures of black hole physics in our initial analogue experiment back in 2017, it was a breakthrough moment for understanding some of the bizarre phenomena that are often challenging, if not impossible, to study otherwise. Now, with our more sophisticated experiment, we have taken this research to the next level, which could eventually lead us to predict how quantum fields behave in curved spacetimes around astrophysical black holes."<br /><br />This groundbreaking research is funded by a £5 million grant from the Science Technology Facilities Council, distributed among teams at seven leading UK institutions, including the University of Nottingham, Newcastle University and King's College London.<br /><br />The project has also been supported by both the UKRI Network grant on Quantum Simulators for Fundamental Physics and the Leverhulme Research Leaders Fellowship held by Professor Silke Weinfurtner.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240320122612.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-36639856735842818442024-03-24T21:31:00.018+01:002024-03-24T21:31:00.130+01:00Enormous ice loss from Greenland glacier<p>Ground-based measuring devices and aircraft radar operated in the far northeast of Greenland show how much ice the 79° N-Glacier is losing. According to measurements conducted by the Alfred Wegener Institute, the thickness of the glacier has decreased by more than 160 metres since 1998. Warm ocean water flowing under the glacier tongue is melting the ice from below. High air temperatures cause lakes to form on the surface, whose water flows through huge channels in the ice into the ocean. One channel reached a height of 500 metres, while the ice above was only 190 metres thick, as a research team has now reported in the scientific journal The Cryosphere.<br /><br />A rustic camp in northeast Greenland was one of the bases for deploying autonomous measuring devices with modern radar technology by helicopter in a part of the 79° N-Glacier that is difficult to access.<br /><br />Measurement flights with the polar aircraft of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and satellite data were also incorporated into a scientific study that has now been published in the scientific journal The Cryosphere. This study examines how global warming affects the stability of a floating ice tongue.<br /><br />This is of great importance for the remaining ice shelves in Greenland as well as those in Antarctica, as instability of the ice shelf usually results in an acceleration of the ice flow, which would lead to a greater sea level rise.<br /><br />"Since 2016, we have been using autonomous instruments to carry out radar measurements on the 79° N-Glacier, from which we can determine melt and thinning rates," says AWI glaciologist Dr Ole Zeising, the first author of the publication.<br /><br />"In addition, we used aircraft radar data from 1998, 2018 and 2021 showing changes in ice thickness. We were able to measure that the 79° N-Glacier has changed significantly in recent decades under the influence of global warming."<br /><br />The study shows how the combination of a warm ocean inflow and a warming atmosphere affects the floating ice tongue of the 79° N-Glacier in northeast Greenland.<br /><br />Only recently, an AWI oceanography team published a modelling study on this subject.<br /><br />The unique data set of observations now presented shows that extremely high melt rates occur over a large area near the transition to the ice sheet.<br /><br />In addition, large channels form on the underside of the ice from the land side, probably because the water from huge lakes drains through the glacier ice.<br /><br />Both processes have led to a strong thinning of the glacier in recent decades.<br /><br />Due to extreme melt rates, the ice of the floating glacier tongue has become 32 % thinner since 1998, especially from the grounding line where the ice comes into contact with the ocean.<br /><br />In addition, a 500-metre-high channel has formed on the underside of the ice, which spreads towards the inland.<br /><br />The researchers attribute these changes to warm ocean currents in the cavity below the floating tongue and to the runoff of surface meltwater as a result of atmospheric warming.<br /><br />A surprising finding was that melt rates have decreased since 2018.<br /><br />A possible cause for this is a colder ocean inflow. "The fact that this system reacts on such short time scales is astonishing for systems that are actually inert such as glaciers," says Prof Dr Angelika Humbert, who is also involved in the study.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240322145451.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-78131232572870293562024-03-24T21:30:00.016+01:002024-03-24T21:30:00.236+01:00If faces look like demons, you could have this extraordinary condition<p>Imagine if every time you saw a face, it appeared distorted. Well, for those who have a very rare condition known as prosopometamorphopsia (PMO), which causes facial features to appear distorted, that is reality.<br /><br />As the Dartmouth-based website about prosopometamorphopsia explains, "'Prosopo' comes from the Greek word for face 'prosopon' while 'metamorphopsia' refers to perceptual distortions.''' Specific symptoms vary from case to case and can affect the shape, size, color, and position of facial features. The duration of PMO also varies; it "can last for days, weeks, or even years."<br /><br />A new Dartmouth study published in the "Clinical Pictures" section of The Lancet reports on a unique case of a patient with PMO.<br /><br />The research is the first to provide accurate and photorealistic visualizations of the facial distortions experienced by an individual with PMO.<br /><br />The patient, a 58-year-old male with PMO, sees faces without any distortions when they are viewed on a screen and on paper, but he sees distorted faces that appear "demonic" when viewed in-person.<br /><br />Most PMO cases however, see distortions in all contexts, so his case is especially rare and presented a unique opportunity to accurately depict his distortions.<br /><br />For the study, the researchers took a photograph of a person's face.<br /><br />Then, they showed the patient the photograph on a computer screen while he looked at the real face of the same person.<br /><br />The researchers obtained real-time feedback from the patient on how the face on the screen and the real face in front of him differed, as they modified the photograph using computer software to match the distortions perceived by the patient.<br /><br />"In other studies of the condition, patients with PMO are unable to assess how accurately a visualization of their distortions represents what they see because the visualization itself also depicts a face, so the patients will perceive distortions on it too," says lead author Antônio Mello, a PhD student in the Department of Psychological and Brain Sciences at Dartmouth.<br /><br />In contrast, this patient doesn't see distortions on a screen.<br /><br />This means that the researchers were able to modify the face in the photograph, and the patient could accurately compare how similar his perception of the real face was to the manipulated photograph.<br /><br />"Through the process, we were able to visualize the patient's real-time perception of the face distortions," says Mello.<br /><br />In their research with other PMO cases, the co-authors state that some of their PMO participants have seen health professionals who wanted to help but diagnosed them with another health condition, not PMO.<br /><br />"We've heard from multiple people with PMO that they have been diagnosed by psychiatrists as having schizophrenia and put on anti-psychotics, when their condition is a problem with the visual system," says senior author Brad Duchaine, a professor of psychological and brain sciences and principal investigator of the Social Perception Lab at Dartmouth.<br /><br />"And it's not uncommon for people who have PMO to not tell others about their problem with face perception because they fear others will think the distortions are a sign of a psychiatric disorder," says Duchaine.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240322145602.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-56596326191183268382024-03-23T22:03:00.020+01:002024-03-23T22:03:00.132+01:00Two of the Milky Way's earliest building blocks identified<p>Astronomers have identified what could be two of the Milky Way's earliest building blocks: Named "Shakti" and "Shiva," these appear to be the remnants of two galaxies that merged between 12 and 13 billion years ago with an early version of the Milky Way, contributing to our home galaxy's initial growth. The new find is the astronomical equivalent of archeologists identifying traces of an initial settlement that grew into a large present-day city. It required combining data for nearly 6 million stars from ESA's Gaia mission with measurements from the SDSS survey. The results have been published in the Astrophysical Journal.<br /><br />The early history of our home galaxy, the Milky Way, is one of joining smaller galaxies, which makes for fairly large building blocks. Now, Khyati Malhan and Hans-Walter Rix of the Max Planck Institute for Astronomy have succeeded in identifying what could be two of the earliest building blocks that can still be recognized as such today: proto-galactic fragments that merged with an early version of our Milky Way between 12 and 13 billion years ago, at the very beginning of the era of galaxy formation in the Universe. The components, which the astronomers have named Shakti and Shiva, were identified by combining data from ESA's astrometry satellite Gaia with data from the SDSS survey. For astronomers, the result is the equivalent of finding traces of an initial settlement that grew into a large present-day city.<br /><br /><b>Tracing the origins of stars that came from other galaxies</b><br /><br />When galaxies collide and merge, several processes happen in parallel. Each galaxy carries along its own reservoir of hydrogen gas. Upon collision, those hydrogen gas clouds are destabilized, and numerous new stars are formed inside. Of course, the incoming galaxies also already have their own stars, and in a merger, stars from the galaxies will mingle. In the long run, such "accreted stars" will also account for some of the stellar population of the newly-formed combined galaxy. Once the merger is completed, it might seem hopeless to identify which stars came from which predecessor galaxy. But in fact, at least some ways of tracing back stellar ancestry exist.<br /><br />Help comes from basic physics. When galaxies collide and their stellar populations mingle, most of the stars retain very basic properties, which are directly linked to the speed and direction of the galaxy in which they originated. Stars from the same pre-merger galaxy share similar values for both their energy and what physicists call angular momentum -- the momentum associated with orbital motion or rotation. For stars moving in a galaxy's gravitational field, both energy and angular momentum are conserved: they remain the same over time. Look for large groups of stars with similar, unusual values for energy and angular momentum -- and chances are, you might find a merger remnant.<br /><br />Additional pointers can assist identification. Stars that formed more recently contain more heavier elements, what astronomers call "metals," than stars that formed a long time ago. The lower the metal content ("metallicity"), the earlier the star presumably formed. When trying to identify stars that already existed 13 billion years ago, one should look for stars with very low metal content ("metal-poor").<br /><br /><b>Virtual excavations in a large data set</b><br /><br />Identifying the stars that joined our Milky Way as parts of another galaxy has only become possible comparatively recently. It requires large, high-quality data sets, and the analysis involves sifting the data in clever ways so as to identify the searched-for class of objects. This kind of data set has only been available for a few years. The ESA astrometry satellite Gaia provides an ideal data set for this kind of big-data galactic archeology. Launched in 2013, it has produced an increasingly accurate data set over the past decade, which by now includes positions, changes in position and distances for almost 1.5 billion stars within our galaxy.<br /><br />Gaia data revolutionized studies of the dynamics of stars in our home galaxy, and has already led to the discovery of previously unknown substructures. This includes the so-called Gaia Enceladus/Sausage stream, a remnant of the most recent larger merger our home galaxy has undergone, between 8 and 11 billion years ago. It also includes two structures identified in 2022: the Pontus stream identified by Malhan and colleagues and the "poor old heart" of the Milky Way identified by Rix and colleagues. The latter is a population of stars that newly formed during the initial mergers that created the proto-Milky Way, and continue to reside in our galaxy's central region.<br /><br /><b>Traces of Shakti and Shiva</b><br /><br />For their present search, Malhan and Rix used Gaia data combined with detailed stellar spectra from the Sloan Digital Sky Survey (DR17). The latter provide detailed information about the stars' chemical composition. Malhan says: "We observed that, for a certain range of metal-poor stars, stars were crowded around two specific combinations of energy and angular momentum."<br /><br />In contrast with the "poor old heart," which was also visible in those plots, the two groups of like-minded stars had comparatively large angular momentum, consistent with groups of stars that had been part of separate galaxies which had merged with the Milky Way. Malhan has named these two structures Shakti and Shiva, the latter one of the principal deities of Hinduism and the former a female cosmic force often portrayed as Shiva's consort.<br /><br />Their energy and angular momentum values, plus their overall low metallicity on par with that of the "poor old heart," makes Shakti and Shiva good candidates for some of the earliest ancestors of our Milky Way. Rix says: "Shakti and Shiva might be the first two additions to the 'poor old heart' of our Milky Way, initiating its growth towards a large galaxy."</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240321155515.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-24393443229468530292024-03-23T22:02:00.018+01:002024-03-23T22:02:00.131+01:00James Webb Space Telescope captures the end of planet formation<p>Scientists believe that planetary systems like our solar system contain more rocky objects than gas-rich ones. Around our sun, these include the inner planets -- Mercury, Venus, Earth and Mars -- the asteroid belt and the Kuiper belt objects such as Pluto.<br /><br />Jupiter, Saturn, Uranus and Neptune, on the other hand, contain mostly gas. But scientists also have known for a long time that planet-forming disks start out with 100 times more mass in gas than solids, which leads to a pressing question: When and how does most of the gas leave a nascent planetary system?<br /><br />A new study led by Naman Bajaj at the University of Arizona Lunar and Planetary Laboratory, published in the Astronomical Journal, provides answers. Using the James Webb Space Telescope, or JWST, the team obtained images from such a nascent planetary system -- also known as a circumstellar disk -- in the process of actively dispersing its gas into surrounding space.<br /><br />"Knowing when the gas disperses is important as it gives us a better idea of how much time gaseous planets have to consume the gas from their surroundings," said Bajaj, a second-year doctoral student at UArizona's Lunar and Planetary Laboratory. "With unprecedented glimpses into these disks surrounding young stars, the birthplaces of planets, JWST helps us uncover how planets form."<br /><br />During the very early stages of planetary system formation, planets coalesce in a spinning disk of gas and tiny dust around the young star, according to Bajaj. These particles clump together, building up into bigger and bigger chunks called planetesimals. Over time, these planetesimals collide and stick together, eventually forming planets. The type, size and location of planets that form depend on the amount of material available and how long it remains in the disk.<br /><br />"So, in short, the outcome of planet formation depends on the evolution and dispersal of the disk," Bajaj said.<br /><br />At the heart of this discovery is the observation of T Cha, a young star -- relative to the sun, which is about 4.6 billion years old -- enveloped by an eroding circumstellar disk notable for a vast dust gap, spanning approximately 30 astronomical units, or au, with one au being the average distance between the Earth and the sun.<br /><br />Bajaj and his team were able, for the first time, to image the disk wind, as the gas is referred to when it slowly leaves the planet-forming disk. The astronomers took advantage of the telescope's sensitivity to light emitted by an atom when high-energy radiation -- for example, in starlight -- strips one or more electrons from its nucleus. This is known as ionization, and the light emitted in the process can be used as a sort of chemical "fingerprint" -- in the case of the T Cha system, tracing two noble gases, neon and argon. The observations also mark the first time a double ionization of argon has been detected in a planet-forming disk, the team writes in the paper.<br /><br />"The neon signature in our images tells us that the disk wind is coming from an extended region away from the disk," Bajaj said. "These winds could be driven either by high-energy photons -- essentially the light streaming from the star -- or by the magnetic field that weaves through the planet-forming disk."<br /><br />In an effort to differentiate between the two, the same group, this time led by Andrew Sellek, a postdoctoral researcher at Leiden University in the Netherlands, performed simulations of the dispersal driven by stellar photons, the intense light streaming from the young star. They compared these simulations to the actual observations and found dispersal by high-energy stellar photons can explain the observations, and hence cannot be excluded as a possibility. That study concluded that the amount of gas dispersing from the T Cha disk every year is equivalent to that of Earth's moon. These results will be published in a companion paper, currently under review with the Astronomical Journal.<br /><br />While neon signatures had been detected in many other astronomical objects, they weren't known to originate in low-mass planet-forming disks until first discovered in 2007 with JWST's predecessor, NASA's Spitzer Space Telescope, by Ilaria Pascucci, a professor at LPL who soon identified them as a tracer of disk winds. Those early findings transformed research efforts focused on understanding gas dispersal from circumstellar disks. Pascucci is the principal investigator on the most recent observing project and a co-author on the publications reported here.<br /><br />"Our discovery of spatially resolved neon emission -- and the first detection of double ionized argon -- using the James Webb Space Telescope could become the next step towards transforming our understanding of how gas clears out of a planet-forming disk," Pascucci said. "These insights will help us get a better idea of the history and impact on our own solar system."<br /><br />In addition, the group has also discovered that the inner disk of T Cha is evolving on very short timescales of decades; they found that the spectrum observed by JWST differs from the earlier spectrum detected by Spitzer. According to Chengyan Xie, a second-year doctoral student at LPL who leads this in-progress work, this mismatch could be explained by a small, asymmetric disk inside of T Cha that has lost some of its mass in the short 17 years that have elapsed between the two observations.<br /><br />"Along with the other studies, this also hints that the disk of T Cha is at the end of its evolution," Xie said. "We might be able to witness the dispersal of all the dust mass in T Cha's inner disk within our lifetime."</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240322145554.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-74281486774030414412024-03-23T22:01:00.017+01:002024-03-23T22:01:00.136+01:00Scientists uncover evidence that microplastics are contaminating archaeological remains<p>Researchers have for the first time discovered evidence of microplastic contamination in archaeological soil samples.<br /><br />The team discovered tiny microplastic particles in deposits located more than seven metres deep, in samples dating back to the first or early second century and excavated in the late 1980s.<br /><br />Preserving archaeology in situ has been the preferred approach to managing historical sites for a generation.<br /><br />However, the research team say the findings could prompt a rethink, with the tiny particles potentially compromising the preserved remains.<br /><br />Microplastics are small plastic particles, ranging from 1μm (one thousandth of a millimetre) to 5mm.<br /><br />They come from a wide range of sources, from larger plastic pieces that have broken apart, or resin pellets used in plastic manufacturing which were frequently used in beauty products up until around 2020.<br /><br />The study, published in the journal Science of the Total Environment, was carried out by the universities of York and Hull and supported by the educational charity York Archaeology.<br /><br />Professor John Schofield from the University of York's Department of Archaeology, said: "This feels like an important moment, confirming what we should have expected: that what were previously thought to be pristine archaeological deposits, ripe for investigation, are in fact contaminated with plastics, and that this includes deposits sampled and stored in the late 1980s.<br /><br />"We are familiar with plastics in the oceans and in rivers. But here we see our historic heritage incorporating toxic elements. To what extent this contamination compromises the evidential value of these deposits, and their national importance is what we'll try to find out next."<br /><br />David Jennings, chief executive of York Archaeology, added: "We think of microplastics as a very modern phenomenon, as we have only really been hearing about them for the last 20 years, when Professor Richard Thompson revealed in 2004 that they have been prevalent in our seas since the 1960s with the post-war boom in plastic production,"<br /><br />"This new study shows that the particles have infiltrated archaeological deposits, and like the oceans, this is likely to have been happening for a similar period, with particles found in soil samples taken and archived in 1988 at Wellington Row in York."<br /><br />The study identified 16 different microplastic polymer types across both contemporary and archived samples.<br /><br />"Where this becomes a concern for archaeology is how microplastics may compromise the scientific value of archaeological deposits. Our best-preserved remains -- for example, the Viking finds at Coppergate -- were in a consistent anaerobic waterlogged environment for over 1000 years, which preserved organic materials incredibly well. The presence of microplastics can and will change the chemistry of the soil, potentially introducing elements which will cause the organic remains to decay. If that is the case, preserving archaeology in situ may no longer be appropriate," added David Jennings.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240322145440.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-15821781373237095142024-03-23T22:00:00.017+01:002024-03-23T22:00:00.246+01:00Researchers propose a new way to identify when babies become conscious<p>Academics are proposing a new and improved way to help researchers discover when consciousness emerges in human infancy.<br /><br />When over the course of development do humans become conscious? When the seventeenth-century French philosopher René Descartes was asked about infant consciousness by his critics, he eventually suggested that infants might have thoughts, albeit ones that are simpler than those of adults. Hundreds of years later, the issue of when human beings become conscious is a question which remains a challenge for psychologists and philosophers alike.<br /><br />But now, in response to a recent article in Trends in Cognitive Sciences, two academics from the University of Birmingham have suggested an improved way to help scientists and researchers identify when babies become conscious.<br /><br />In a Letter to the Editor, also published in Trends in Cognitive Sciences, Dr Henry Taylor, Associate Professor of Philosophy, and Andrew Bremner, Professor of Developmental Psychology, have explored a new approach which is being proposed, that involves identifying markers of consciousness in adults, and then measuring when babies start to exhibit larger numbers of these in development.<br /><br />Dr Taylor says: "For example, imagine that in adults, we know that a certain very specific behaviour, or a specific pattern of brain activation always comes along with consciousness. Then, if we can identify when this behaviour or brain activation arises in babies, we have good reason to think that this is when consciousness emerges in babies. Behaviours and brain activations like this are what we call 'markers' of consciousness."<br /><br />This kind of approach is desperately needed since babies (unlike adults) cannot tell you what they are conscious of. Professor Bremner said: "It is really hard to establish when babies become conscious. This is mostly because infants can't report their experiences and, as most parents will know, can be rather uncooperative particularly when it comes to experimental tasks. As we can't just ask babies when they become conscious, the best approach is to try to identify a broad range of markers of consciousness, which appear in early development and late development, and then group them together, this could help us identify when consciousness emerges."<br /><br />In the recent article the researchers (Prof. Tim Bayne and colleagues) suggested four specific markers of consciousness, some of which are present in the late stages of gestation, and others which are found in early infancy. Based on this, the study argues that consciousness emerges early (from the last prenatal trimester).<br /><br />But Professor Bremner and Dr Taylor say that this ignores other markers of consciousness. Previous research has identified a separate cluster of markers. These include:<br /><br />• Pointing (bringing a social partner's attention to an object and checking). • Intentional control (intentional means-end coordination of actions -- e.g., pulling a support to retrieve a distal object). • Explicit memory (deferred imitation of actions).<br /><br />Dr Taylor said: "One of the complicated issues is that it does not look like all the markers point to the same age for the emergence of consciousness. The ones mentioned by Bayne and colleagues suggest somewhere between the third trimester of pregnancy and early infancy, but other markers suggest the age might be around one year old. In fact, at the really extreme end, some markers only emerge at around 3-4 years. Because there are so many different markers of consciousness which appear in early and late development it is extremely hard to come to a conclusion."<br /><br />Professor Bremner concluded: "We propose that a broad approach to markers, including those that emerge in early and late stage, is needed. We also recommend that a range of developmental models of the onset of consciousness should be considered. For instance, it may be that some markers emerge in one cluster in early development, with others in a later cluster. As well as this there may be a continuous and gradual emergence of certain markers stretching over gestation and throughout early life.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240322145426.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-76733948735833901982024-03-22T21:33:00.016+01:002024-03-22T21:33:00.137+01:00Astrophysicist's research could provide a hint in the search for dark matter<p>Dark matter is one of science's greatest mysteries. Although it is believed to make up about 85 percent of the cosmos, scientists know very little about its fundamental nature. Research by Clemson University postdoctoral fellow Alex McDaniel provides some of the most stringent constraints on the nature of dark matter yet. It also revealed a small hint of a signal that, if real, could be confirmed in the next decade or so.<br /><br />Dark matter is one of science's greatest mysteries.<br /><br />It doesn't absorb, reflect or emit light, so we can't see it. But its presence is implied by the gravitational effects it appears to have on galaxies.<br /><br />Although dark matter makes up about 85 percent of the cosmos, scientists know very little about its fundamental nature.<br /><br />Theories abound, and research by Clemson University postdoctoral fellow Alex McDaniel provides some of the most stringent constraints on the nature of dark matter yet.<br /><br />His research also reveals a small hint of a signal that, if real, could be confirmed sometime in the next decade or so.<br /><br />"With data collection and new discoveries in the future, this small hint could potentially turn into a very concrete detection of a dark matter model," McDaniel said.<br /><br />Detecting dark matter would be groundbreaking.<br /><br />"Dark matter is one of the most important things in astrophysics, and we know next to nothing about it. Discovering it will be a tremendous breakthrough," said Marco Ajello, an associate professor in the Clemson Department of Physics and Astronomy and McDaniel's adviser.<br /><br />"Whoever discovers may win a Nobel Prize. It's that big."<br /><br />In this work, McDaniel and collaborators were searching dwarf galaxies for dark matter that self-annihilates into ordinary matter and gamma rays, a form of light at the highest energy levels.<br /><br />Dwarf galaxies are ideal for study because they are small, rich in dark matter and mostly lack other astrophysics phenomena such as gas, dust and supernova that could contaminate the findings.<br /><br />"We look for these because, ideally, they give us a clean signal or allow us to rule out certain particle theories," McDaniel said.<br /><br />Some models predict that dark matter has a certain mass or cross section, which is the probability of a specific event occurring due to the interaction of particles.<br /><br />That would determine what researchers would expect to see in gamma rays.<br /><br />If they don't see that, they can rule out those masses and cross sections, he said.<br /><br />"In this paper, we do more ruling out, saying that dark matter can't have those masses or cross section," said Chris Karwin, a former postdoc at Clemson and a co-author of the study.<br /><br />Karwin is now a postdoctoral fellow at the NASA Goddard Space Flight Center.<br /><br />"But compared to previous studies, we do start to see a hint of something that might be a signal from these systems."<br /><br />McDaniel's study uses the larger samples that include additional discovered dwarf galaxies and larger amounts of data than previous studies.<br /><br />He included about 50 dwarf galaxies in his study but said that with new, more powerful telescopes coming online in the near future, he expects that number to increase to 150-200.<br /><br />"The new telescopes are basically dwarf galaxy detectors," he said.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240320122544.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-43484560446545767452024-03-22T21:32:00.020+01:002024-03-22T21:32:00.148+01:00Say hello to biodegradable microplastics<p>Microplastics are tiny, nearly indestructible fragments shed from everyday plastic products. As we learn more about microplastics, the news keeps getting worse. Already well-documented in our oceans and soil, we're now discovering them in the unlikeliest of places: our arteries, lungs and even placentas. Microplastics can take anywhere from 100 to 1,000 years to break down and, in the meantime, our planet and bodies are becoming more polluted with these materials every day.<br /><br />Finding viable alternatives to traditional petroleum-based plastics and microplastics has never been more important. New research from scientists at the University of California San Diego and materials-science company Algenesis shows that their plant-based polymers biodegrade -- even at the microplastic level -- in under seven months. The paper, whose authors are all UC San Diego professors, alumni or former research scientists, appears in Nature Scientific Reports.<br /><br />"We're just starting to understand the implications of microplastics. We've only scratched the surface of knowing the environmental and health impacts," stated Professor of Chemistry and Biochemistry Michael Burkart, one of the paper's authors and an Algenesis co-founder. "We're trying to find replacements for materials that already exist, and make sure these replacements will biodegrade at the end of their useful life instead of collecting in the environment. That's not easy."<br /><br />"When we first created these algae-based polymers about six years ago, our intention was always that it be completely biodegradable," said another of the paper's authors, Robert Pomeroy, who is also a professor of chemistry and biochemistry and an Algenesis co-founder. "We had plenty of data to suggest that our material was disappearing in the compost, but this is the first time we've measured it at the microparticle level."<br /><br /><b>Putting it to the test</b><br /><br />To test its biodegradability, the team ground their product into fine microparticles, and used three different measurement tools to confirm that, when placed in a compost, the material was being digested by microbes.<br /><br />The first tool was a respirometer. When the microbes break down compost material, they release carbon dioxide (CO2), which the respirometer measures. These results were compared to the breakdown of cellulose, which is considered the industry standard of 100% biodegradability. The plant-based polymer matched the cellulose at almost one hundred percent.<br /><br />Next the team used water flotation. Since plastics are not water soluble and they float, they can easily be scooped off the surface of water. At intervals of 90 and 200 days, almost 100% of the petroleum-based microplastics were recovered, meaning none of it had biodegraded. On the other hand, after 90 days, only 32% of the algae-based microplastics were recovered, showing that more than two thirds of it had biodegraded. After 200 days, only 3% was recovered indicating that 97% of it had disappeared.<br /><br />The last measurement involved chemical analysis via gas chromatography/mass spectrometry (GCMS), which detected the presence of the monomers used to make the plastic, indicating that the polymer was being broken to its starting plant materials. Scanning-electron microscopy further showed how microorganisms colonize the biodegradable microplastics during composting.<br /><br />"This material is the first plastic demonstrated to not create microplastics as we use it," said Stephen Mayfield, a paper coauthor, School of Biological Sciences professor and co-founder of Algenesis. "This is more than just a sustainable solution for the end-of-product life cycle and our crowded landfills. This is actually plastic that is not going to make us sick."<br /><br />Creating an eco-friendly alternative to petroleum-based plastics is only one part of the long road to viability. The ongoing challenge is to be able to use the new material on pre-existing manufacturing equipment that was originally built for traditional plastic, and here Algenesis is making progress. They have partnered with several companies to make products that use the plant-based polymers developed at UC San Diego, including Trelleborg for use in coated fabrics and RhinoShield for use in the production of cell phone cases.<br /><br />"When we started this work, we were told it was impossible," stated Burkart. "Now we see a different reality. There's a lot of work to be done, but we want to give people hope. It is possible."</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240321155439.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-74845866313154419582024-03-22T21:31:00.014+01:002024-03-22T21:31:00.130+01:00Your dog understands that some words 'stand for' objects<p>It's no surprise that your dog can learn to sit when you say "sit" and come when called. But a study appearing March 22 in the journal Current Biology has made the unexpected discovery that dogs generally also know that certain words "stand for" certain objects. When dogs hear those words, brain activity recordings suggest they activate a matching mental representation in their minds.<br /><br />"Dogs do not only react with a learned behavior to certain words," says Marianna Boros of the Department of Ethology at the Eötvös Loránd University, Budapest, Hungary, one of the paper's co-first authors. "They also don't just associate that word with an object based on temporal contiguity without really understanding the meaning of those words, but they activate a memory of an object when they hear its name."<br /><br />Word understanding tests with individuals who do not speak, such as infants and animals, usually require active choice, the researchers say. They're asked to show or get an object after hearing its name. Very few dogs do well on such tests in the lab, often fetching objects correctly at a rate expected by chance.<br /><br />The researchers wanted to look closer at dogs' implicit understanding of object words by measuring brain activity using non-invasive EEG without asking them to act. The idea was that this might offer a more sensitive measure of their understanding of language.<br /><br />In their studies, they had 18 dog owners say words for toys their dogs knew and then present the objects to them. Sometimes they presented the matching toy, while other times they would present an object that didn't match. For example, an owner would say, "Zara, look, the ball," and present the object while the dog's brain activity was captured on EEG.<br /><br />The brain recording results showed a different pattern in the brain when the dogs were shown a matching object versus a mismatched one. That's similar to what researchers have seen in humans and is widely accepted as evidence that they understand the words. The researchers also found a greater difference in those patterns for words that dogs knew better, offering further support for their understanding of object words. Interestingly, while the researchers thought this ability might depend on having a large vocabulary of object words, their findings showed that it doesn't.<br /><br />"Because typical dogs learn instruction words rather than object names, and there are only a handful of dogs with a large vocabulary of object words, we expected that dogs' capacity for referential understanding of object words will be linked to the number of object words they know; but it wasn't," says Lilla Magyari, also of Eötvös Loránd University and University of Stavanger and the other co-first author.<br /><br />"It doesn't matter how many object words a dog understands -- known words activate mental representations anyway, suggesting that this ability is generally present in dogs and not just in some exceptional individuals who know the names of many objects," Boros added.<br /><br />The discovery that dogs as a species may generally have a capacity to understand words in a referential way, just as humans do, might reshape the way scientists think about the uniqueness of how humans use and understand language, the researchers say. That has important implications for theories and models of language evolution. For dog owners, it's also an important realization.<br /><br />"Your dog understands more than he or she shows signs of," Magyari says. "Dogs are not merely learning a specific behavior to certain words, but they might actually understand the meaning of some individual words as humans do."</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240322145438.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-65498044304649051082024-03-22T21:30:00.020+01:002024-03-22T21:30:00.136+01:00Study reveals 'cozy domesticity' of prehistoric stilt-house dwellers in England's ancient marshland<p>A major report on the remains of a stilt village that was engulfed in flames almost 3,000 years ago reveals in unprecedented detail the daily lives of England's prehistoric fenlanders.<br /><br />Must Farm, a late Bronze Age settlement, dates to around 850BC, with University of Cambridge archaeologists unearthing four large wooden roundhouses and a square entranceway structure -- all of which had been constructed on stilts above a slow-moving river.<br /><br />The entire hamlet stood approximately two metres above the riverbed, with walkways bridging some of the main houses, and was surrounded by a two-metre-high fence of sharpened posts.<br /><br />The settlement was less than a year old when it was destroyed by a catastrophic fire, with buildings and their contents collapsing into the muddy river below. The combination of charring and waterlogging led to exceptional preservation. The site has been described as "Britain's Pompeii."<br /><br />Years of research conducted on thousands of artefacts from the site have now shown that early Fen folk had surprisingly comfortable lifestyles, with domestic layouts similar to modern homes, meals of "honey-glazed venison" and clothes of fine flax linen, and even a recycling bin.<br /><br />The settlement-on-stilts also contained a stack of spears with shafts over three metres long, as well as a necklace with beads from as far away as Denmark and Iran, and a human skull rendered smooth by touch, perhaps a memento of a lost loved one.<br /><br />The Cambridge archaeologists say the site provides a unique "blueprint" for the circular architecture, home interiors and overall domesticity of those who inhabited the swampy fenland of East Anglia some eight centuries before Romans set foot on British shores.<br /><br />Full findings from the Must Farm site -- excavated by the Cambridge Archaeological Unit (CAU) in 2015-16 after its discovery on the edge of Whittlesey near Peterborough -- are published in two reports, both made available by Cambridge's McDonald Institute for Archaeological Research.<br /><br />"These people were confident and accomplished home-builders. They had a design that worked beautifully for an increasingly drowned landscape," said CAU's Mark Knight, report co-author and excavation director.<br /><br />"While excavating the site there was a sense that its Bronze Age residents had only just left. You could almost see and smell their world, from the glint of metal tools hanging on wattled walls to the sharp milkiness of brewed porridge."<br /><br /><b>'Mirror' of ancient home interiors</b><br /><br />The ruins of five structures were uncovered, along with walkways and fencing, but the original settlement was likely twice as big -- half the site was removed by 20th century quarrying -- with researchers saying it may have held up to sixty occupants in family units.<br /><br />The river running underneath the community would have been shallow, sluggish and thick with vegetation. This cushioned the scorched remains where they fell, creating an archaeological "mirror" of what had stood above -- allowing researchers to map the layout of the structures.<br /><br />One of the main roundhouses, with almost fifty square metres of floor space, appeared to have distinct activity zones comparable to rooms in a modern home.<br /><br />"Conducting research on Must Farm is a bit like getting an estate agent's tour of a Bronze Age stilt house," said David Gibson, report co-author and Archaeological Manager at CAU.<br /><br />Ceramic and wooden containers, including tiny cups, bowls, and large storage jars, were found in the northeast quadrant of "Structure One," the location of a kitchen. Some pots were even nested: designed to stack inside one another to save space.<br /><br />Metal tools were stored along the building's eastern side, while the empty northwest area was probably reserved for sleeping. The southeast space had lots of cloth fragments, along with bobbins and loom weights. This was close to a likely entrance, where extra light would have helped with textile work.<br /><br />The roundhouse's southwest quadrant was reserved for keeping lambs indoors. There was no evidence of humans dying in the fire, but several young sheep had been trapped and burnt alive.<br /><br />Skeletal remains showed the lambs were three to six months old, suggesting the settlement was destroyed sometime in late summer or early autumn. Evidence that the wooden architecture was still "green" confirms construction took place around nine months to a year earlier.<br /><br /><b>Tool kits, textiles and a token of good luck</b><br /><br />Household inventories were remarkably consistent. All the roundhouses contained a metalwork "tool kit" that included sickles (crop-harvesting blades) along with axes and curved "gouges" used to hack and chisel wood, as well as hand-held razors for cutting hair.<br /><br />Most buildings had objects for making textiles, from spindle whorls to thread bobbins, although the distribution suggests that "spinning" -- the process of twisting fibres together -- was conducted in three of the roundhouses, but Structure One was where this yarn got converted to fabrics.<br /><br />The textiles are the finest of this period found in Europe, with details such as "pile tufts" that would have given garments a soft, almost velvety feel, and "tubular selvedge" for neat seams and hems.<br /><br />Each roundhouse roof had three layers: insulating straw topped by turf and completed with clay -- making them warm and waterproof but still well ventilated. "In a freezing winter, with winds cutting across the Fens, these roundhouses would have been pretty cosy," said CAU project archaeologist Dr Chris Wakefield.<br /><br />Structure Four, a smaller square building, may also have acted as the settlement's entrance. A large wooden bucket had been kept within, containing several damaged bronze objects and worn axe-heads, waiting to be smelted down and recycled into new tools.<br /><br />Encircling the footprint of each roundhouse were "middens," haloes of rubbish dumped from the stilt village above, included broken pots, butchered animal bone, and "coprolites" or fossilised faeces. Some human coprolites had parasite eggs, suggesting inhabitants struggled with intestinal worms.<br /><br />One item, however, had been placed in the silt directly beneath Structure One: an intact hafted axe, perhaps a token of good fortune, or an offering to some kind of spirit on completion of the build.<br /><br /><b>'Meaty porridge'</b><br /><br />Despite millennia in the mud, many artefacts still bore traces of daily life -- along with its sudden interruption as inhabitants abandoned their possessions to escape the blaze.<br /><br />For example, a pottery bowl with the finger-marks of its maker captured in the clay was found still holding its final meal: a wheat-grain porridge mixed with animal fats (possibly goat or red deer). The wooden spatula used for stirring was resting against the inside of the bowl.<br /><br />"It appears the occupants saved their meat juices to use as toppings for porridge," said Dr Chris Wakefield. "The site is providing us with hints of recipes for Bronze Age breakfasts and roast dinners."<br /><br />"Chemical analyses of the bowls and jars showed traces of honey along with ruminant meats such as deer, suggesting these ingredients were combined to create a form of prehistoric honey-glazed venison."<br /><br />The stilt-house dwellers even had favourite cuts of meat, often only bringing the forelegs of a boar back for roasting, for example. Preferred aquatic dishes included pike and bream.<br /><br />Several small dog skulls suggest the animals were kept domestically, perhaps as pets but also to help flush out prey on a hunt. Dog coprolites show they fed on scraps from their owners' meals.<br /><br />Must Farm's residents used the local woodlands -- evidence suggests within a two-mile radius -- to hunt boar and deer, graze sheep, and harvest crops such as wheat and flax as well as wood for construction. Waterways were vital for transporting all these materials.<br /><br />The remains of nine log-boats, canoes hollowed from old tree trunks, were found upstream, dating from across the Bronze and into the Iron Age, included some that were contemporary to Must Farm.<br /><br />"Boat journeys through reed swamps to the woodlands would have been made many times during the site's short life," said Wakefield. "In summer, that meant traversing clouds of mosquitos."<br /><br />Much of what was retrieved from Must Farm were everyday items, the Bronze Age equivalent to the TV remotes and coffee mugs of our own lives. However, some items would have been precious.<br /><br />A necklace of beads made from glass, amber, siltstone and shale had been lost in the fire. In fact, decorative beads were found right across the site. All but one of Must Farm's 49 glass beads came from far-flung places, including Northern and Eastern Europe, and even the Middle East.<br /><br />"Such items would gradually make their way across thousands of miles in a long series of small trades," said Wakefield.<br /><br /><b>Up in flames…</b><br /><br />The researchers say that, while the Bronze Age could be violent, and aspects of the site's structure are clearly defensive, its location may be as much to do with resources. Spears found on site, up to 3.4 metres in length, as well as swords, were as likely to be used in animal hunts as on rival groups.<br /><br />A few human remains were recovered, including the skull of an adult woman polished by repeated touch -- a sign this may have been a keepsake of love rather than war.<br /><br />"The cause of the fire that tore through the settlement will probably never be known," said CAU's David Gibson. "Some argue it may have come under attack, as the occupants never returned for their goods, which would have been fairly easy to retrieve from the shallow waters."<br /><br />However, others think it more likely to have been an accident. If an internal fire took hold in one of the roundhouses, it would spread between the tightknit structures within minutes.<br /><br />Added Gibson: "A settlement like this would have had a shelf-life of maybe a generation, and the people who built it had clearly constructed similar sites before. It may be that after the fire, they simply started again."<br /><br />"There is every possibility that the remains of many more of these stilted settlements are buried across Fenland, waiting for us to find them."</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240320122600.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-40667220407833717272024-03-21T21:33:00.019+01:002024-03-21T21:33:01.435+01:00Scientists find one of the most ancient stars that formed in another galaxy<p>The first generation of stars transformed the universe. Inside their cores, simple hydrogen and helium fused into a rainbow of elements. When these stars died, they exploded and sent these new elements across the universe. The iron running in your veins and the calcium in your teeth and the sodium powering your thoughts were all born in the heart of a long-dead star.<br /><br />No one has been able to find one of those first generation of stars, but scientists have announced a unique finding: a star from the second generation that originally formed in a different galaxy from ours.<br /><br />"This star provides a unique window into the very early element-forming process in galaxies other than our own," said Anirudh Chiti, a University of Chicago postdoctoral fellow and first author on a paper announcing the findings. "We have built up an idea of the how these stars that were chemically enriched by the first stars look like in the Milky Way, but we don't yet know if some of these signatures are unique, or if things happened similarly across other galaxies."<br /><br />The paper was published March 20 in Nature Astronomy.<br /><br /><b>'Fishing needles out of haystacks'</b><br /><br />Chiti specializes in what is called stellar archaeology: Reconstructing how the earliest generations of stars changed the universe. "We want to understand what the properties of those first stars were and what were the elements they produced," said Chiti.<br /><br />But no one has yet managed to directly see these first-generation stars, if any remain in the universe. Instead, Chiti and his colleagues look for stars that formed from the ashes of that first generation.<br /><br />It's hard work, because even the second generation of stars is now incredibly ancient and rare. Most stars in the universe, including our own sun, are the result of tens to thousands of generations, building up more and more heavy elements each time. "Maybe fewer than 1 in 100,000 stars in the Milky Way is one of these second-gen stars," he said. "You really are fishing needles out of haystacks."<br /><br />But it's worth it to get snapshots of what the universe looked like back in time. "In their outer layers, these stars preserve the elements near where they formed," he explained. "If you can find a very old star and get its chemical composition, you can understand what the chemical composition of the universe was like where that star formed, billions of years ago."<br /><br /><b>An intriguing oddity</b><br /><br />For this study, Chiti and his colleagues aimed their telescopes at an unusual target: the stars that make up the Large Magellanic Cloud.<br /><br />The Large Magellanic Cloud is a bright swath of stars visible to the naked eye in the Southern Hemisphere. We now think it was once a separate galaxy that was captured by the Milky Way's gravity just a few billion years ago. This makes it particularly interesting because its oldest stars were formed outside the Milky Way -- giving astronomers a chance to learn about whether conditions in the early universe all looked the same, or were different in other places.<br /><br />The scientists searched for evidence of these particularly ancient stars in the Large Magellanic Cloud and catalogued ten of them, first with the European Space Agency's Gaia satellite and then with the Magellan Telescope in Chile.<br /><br />One of these stars immediately jumped out as an oddity. It had much, much less of the heavier elements in it than any other star yet seen in the Large Magellanic Cloud. This means it was probably formed in the wake of the first generation of stars -- so it had not yet built up heavier elements over the course of repeated star births and deaths.<br /><br />Mapping out its elements, the scientists were surprised to see that it had a lot less carbon than iron compared to what we see in Milky Way stars.<br /><br />"That was very intriguing, and it suggests that perhaps carbon enhancement of the earliest generation, as we see in the Milky Way, was not universal," Chiti said. "We'll have to do further studies, but it suggests there are differences from place to place.<br /><br />"I think we're filling out the picture of what the early element enrichment process looked like in different environments," he said.<br /><br />Their findings also corroborated other studies that have suggested that the Large Magellanic Cloud made much fewer stars early on compared to the Milky Way.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240320160355.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0tag:blogger.com,1999:blog-5104789594895975924.post-74016565744972183312024-03-21T21:32:00.016+01:002024-03-21T21:32:00.700+01:00Icy impacts: Planetary scientists use physics and images of impact craters to gauge the thickness of ice on Europa<p>Sometimes planetary physics is like being in a snowball fight. Most people, if handed an already-formed snowball, can use their experience and the feel of the ball to guess what kind of snow it is comprised of: packable and fluffy, or wet and icy.<br /><br />Using nearly the same principles, planetary scientists have been able to study the structure of Europa, Jupiter's icy moon.<br /><br />Europa is a rocky moon, home to saltwater oceans twice the volume of Earth's, encased in a shell of ice.<br /><br />Scientists have long thought that Europa may be one of the best places in our solar system to look for nonterrestrial life.<br /><br />The likelihood and nature of that life, though, heavily depend on the thickness of its icy shell, something astronomers have not yet been able to ascertain.<br /><br />A team of planetary science experts including Brandon Johnson, an associate professor, and Shigeru Wakita, a research scientist, in the Department of Earth, Atmospheric, and Planetary Sciences in Purdue University's College of Science, announced in a new paper published in Science Advances [ES1] that Europa's ice shell is at least 20 kilometers thick.<br /><br />To reach their conclusion, the scientists studied large craters on Europa, running a variety of models to determine what combination of physical characteristics could have created such a surface structure.<br /><br />"This is the first work that has been done on this large crater on Europa," Wakita said.<br /><br />"Previous estimates showed a very thin ice layer over a thick ocean. But our research showed that there needs to be a thick layer -- so thick that convection in the ice, which has previously been debated, is likely."<br /><br />Using data and images from the spacecraft Galileo, which studied Europa in 1998, Johnson analyzed the impact craters to decode truths about Europa's structure.<br /><br />An expert in planetary physics and colossal collisions, Johnson has studied almost every major planetary body in the solar system.<br /><br />Scientists have long debated the thickness of Europa's ice shell; no one has visited to measure it directly, so scientists are creatively using the evidence at hand: the craters on Europa's icy surface.<br /><br />"Impact cratering is the most ubiquitous surface process shaping planetary bodies," Johnson said.<br /><br />"Craters are found on almost every solid body we've ever seen. They are a major driver of change in planetary bodies. When an impact crater forms, it is essentially probing the subsurface structure of a planetary body. By understanding the sizes and shapes of craters on Europa and reproducing their formation with numerical simulations, we're able to infer information about how thick its ice shell is."<br /><br />Europa is a frozen world, but the ice shelters a rocky core.<br /><br />The icy surface, though, is not stagnant. Plate tectonics and convection currents in the oceans and the ice itself refresh the surface fairly frequently.<br /><br />This means the surface itself is only 50 million to 100 million years old -- which sounds old to short-lived organisms like humans, but is young as far as geological periods go.<br /><br />That smooth, young surface means that craters are clearly defined, easier to analyze and not very deep.<br /><br />Their impacts tell scientists more about the icy shell of the moon and the water ocean below, rather than conveying much information about its rocky heart.</p><p>Read more at <a href="https://www.sciencedaily.com/releases/2024/03/240320160436.htm" target="_blank">Science Daily</a> <br /></p>Danny Bostonhttp://www.blogger.com/profile/09786200117214845277noreply@blogger.com0