One of the worst symptoms associated with inflammation or cancer of the pancreas is severe chronic pain. Pancreatic pain is difficult to treat, because many painkillers prove ineffective in pancreatic patients. In a recent study, a team at the Technical University of Munich (TUM) discovered the cause of this phenomenon for the first time: a particular neuroenzyme in the body is present in the nerves of the organ in high concentrations.
In many cases only potent analgesics such as opiates are able to relieve the suffering of those affected. But these medications have serious side effects, including dependency, fatigue and constipation. For this reason, scientists have long been searching for better pain therapies for pancreatic patients.
Dr. Ihsan Ekin Demir and his team in the Department of Surgery at TUM's university hospital Rechts der Isar wanted to find out why pain treatment is so difficult and often ineffective in diseases of the pancreas.
Pain mediator profile of the pancreas
They examined pancreatic tissue samples from 42 female and male patients with chronic inflammation (chronic pancreatitis) or cancer of the organ (pancreatic carcinoma). The samples were taken from the head region of the organ. In this area, the nerve density is particularly high, and the pancreatic head is therefore often surgically removed for therapeutic reasons. Tissue donations from healthy subjects served as controls in the new study. The scientists determined the levels of the most important neurotransmitters and neuroenzymes present in nerves of the pancreas for communication and signal transmission.
"We've created a pain mediator profile for this region of the pancreas, which plays a key role in the development and perception of pain. This makes it easy to detect pathological changes," explains Ekin Demir, head of the study.
Inhibitors successfully tested in an animal model
It turned out that a specific enzyme was greatly increased in the nerves of the pancreatic tissue patient samples that were examined: neuronal nitric oxide synthetase (nNOS). This enzyme is responsible for the synthesis of the messenger NO, which plays a role in, among other things, the development of pain. In particular, NO leads to neuronal hyperactivation by binding to receptors on the neuronal surface.
When the scientists then added extracts from the patient samples to nerve cell cultures, the quantity of the nNOS enzyme increased in the cultured nerve cells.
In a well-established mouse model for pancreatic diseases, they then used a specific inhibitor that blocks nNOS. This substance is already approved as an experimental drug but cannot yet be used in humans. Demir's team found that mice receiving the drug were much less sensitive to touch in the affected abdominal area than the control animals. This serves as an indicator of pain perception.
Read more at Science Daily
Oct 2, 2019
Carbon emissions soar as tourism reaches new heights
A researcher at The University of Texas at San Antonio (UTSA) is examining how the flight routes people take to get to tourist destinations impact the amount of pollution in the air in a newly published study he coauthored in the Annals of Tourism Research.
"This paper provides one of the first efforts to quantify the carbon emissions associated with tourist air travel in the continental United States," explained Neil Debbage, assistant professor of geography and environmental sustainability in UTSA's Department of Political Science and Geography.
The researchers wanted to know whether nonstop routes to tourist destinations can mitigate air travel carbon emissions compared to connecting routes through big airline hubs.
Using International Civil Aviation Organization data, USTA researchers analyzed carbon emissions for direct and connecting routes between the 10 most-populated metropolitan areas in the northeastern United States (New York, Philadelphia, Boston, etc.) and 13 different tourist destinations located in the Sunbelt and Western regions of the United States (Bexar County, Texas; Los Angeles County, California; Miami-Dade County, Florida; etc.).
Some of the key findings:
"One potential tactic to mitigate the carbon footprint associated with tourist air travel is to select nonstop routes whenever possible," replied Debbage, who worked on the paper with Keith G. Debbage, professor of geography at the University of North Carolina at Greensboro.
The researchers said they hope this paper will help policymakers consider making new initiatives that accelerate technological innovations regarding aircraft fuel usage, jet engines and jet fuel. Additionally, they also emphasized the importance of broader structural shifts such as implementing realistic carbon pricing for air travel.
Neil Debbage's research focuses on climate change, natural hazards and resiliency. He utilizes geographic information systems, statistical modeling and numerical weather modeling to better understand the changing climate at various scales.
From Science Daily
"This paper provides one of the first efforts to quantify the carbon emissions associated with tourist air travel in the continental United States," explained Neil Debbage, assistant professor of geography and environmental sustainability in UTSA's Department of Political Science and Geography.
The researchers wanted to know whether nonstop routes to tourist destinations can mitigate air travel carbon emissions compared to connecting routes through big airline hubs.
Using International Civil Aviation Organization data, USTA researchers analyzed carbon emissions for direct and connecting routes between the 10 most-populated metropolitan areas in the northeastern United States (New York, Philadelphia, Boston, etc.) and 13 different tourist destinations located in the Sunbelt and Western regions of the United States (Bexar County, Texas; Los Angeles County, California; Miami-Dade County, Florida; etc.).
Some of the key findings:
- Nearly half of the routes analyzed exceeded an individual's annual mobility carbon budget for all forms of transportation.
- Direct routes tended to outperform connecting routes regarding carbon emissions.
- On average the difference between direct and connecting routes was equivalent to operating a refrigerator for an entire year (or roughly 100 carbon dioxide kg/person).
- The majority of direct routes in the database generated carbon emissions below the 575 carbon dioxide kg/person annual mobility cap.
"One potential tactic to mitigate the carbon footprint associated with tourist air travel is to select nonstop routes whenever possible," replied Debbage, who worked on the paper with Keith G. Debbage, professor of geography at the University of North Carolina at Greensboro.
The researchers said they hope this paper will help policymakers consider making new initiatives that accelerate technological innovations regarding aircraft fuel usage, jet engines and jet fuel. Additionally, they also emphasized the importance of broader structural shifts such as implementing realistic carbon pricing for air travel.
Neil Debbage's research focuses on climate change, natural hazards and resiliency. He utilizes geographic information systems, statistical modeling and numerical weather modeling to better understand the changing climate at various scales.
From Science Daily
Oct 1, 2019
No need to cut down red and processed meat, controversial findings suggest
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| Meats and vegetables on a grill. |
A panel of international scientists systematically reviewed the evidence and have recommended that most adults should continue to eat their current levels of red and processed meat.
The researchers performed four systematic reviews focused on randomized controlled trials and observational studies looking at the impact of red meat and processed meat consumption on cardiometabolic and cancer outcomes.
In one review of 12 trials with 54,000 people, the researchers did not find statistically significant or an important association between meat consumption and the risk of heart disease, diabetes or cancer.
In three systematic reviews of cohort studies following millions of people, a very small reduction in risk among those who had three fewer servings of red or processed meat a week, but the association was uncertain.
The authors also did a fifth systematic review looking at people's attitudes and health-related values around eating red and processed meats. They found people eat meat because they see it as healthy, they like the taste and they are reluctant to change their diet.
The five systematic reviews, a recommendation and an editorial on the topic were published in the Annals of Internal Medicine today.
McMaster professor Gordon Guyatt, chair of the guideline committee, said the research group with a panel of 14 members from seven countries used a rigorous systematic review methodology, and GRADE methods which rate the certainty of evidence for each outcome, to move from evidence to dietary recommendations to develop their guidelines.
"There is a worldwide interest in nutrition and the issue of red meat in particular. People need to be able to make decisions about their own diet based on the best information available," he said.
Bradley Johnston, corresponding author on the reviews and guideline, said the research team realizes its work is contrary to many current nutritional guidelines.
"This is not just another study on red and processed meat, but a series of high quality systematic reviews resulting in recommendations we think are far more transparent, robust and reliable," said Johnston, who is a part-time associate professor at McMaster and an associate professor of community health and epidemiology at Dalhousie.
He added: "We focused exclusively on health outcomes, and did not consider animal welfare or environmental concerns when making our recommendations.
"We are however sympathetic to animal welfare and environmental concerns with a number of the guideline panel members having eliminated or reduced their personal red and processed meat intake for these reasons."
The accompanying editorial by authors at the Indiana University School of Medicine said: "This is sure to be controversial, but is based on the most comprehensive review of the evidence to date. Because that review is inclusive, those who seek to dispute it will be hard pressed to find appropriate evidence with which to build an argument."
Read more at Science Daily
Fruit flies live longer with combination drug treatment
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| Fruit flies in laboratory. |
The three drugs are all already in use as medical treatments: lithium as a mood stabiliser, trametinib as a cancer treatment and rapamycin as an immune system regulator.
The findings, published in Proceedings of the National Academy of Sciences (PNAS), suggest that a combination drug treatment may one day be helpful at preventing age-related diseases in people.
"As life expectancies increase, we are also seeing an increase of age-related diseases so there is an urgent need to find ways to improve health in old age," said the study's co-lead author, Dr Jorge Castillo-Quan, who began the research at the UCL Institute of Healthy Ageing before moving to Joslin Diabetes Center, Harvard Medical School.
"Here, by studying fruit flies which age much more rapidly than people, we have found that a combination drug treatment targeting different cellular processes may be an effective way to slow down the ageing process."
The researchers were building on previous studies finding that lithium, trametinib and rapamycin can each extend lifespan in fruit flies (Drosophila), which is supported by other preliminary evidence in mice, worms, and cells, and observational findings in people.
The three drugs all act on different cellular signalling pathways that together form the nutrient sensing network, which is conserved across evolution from worms and flies all the way to humans. This network adjusts what the body is doing in response to changes in nutrient levels. The three drugs in question act on different proteins of this network to slow the ageing process and delay the onset of age-related death.
For the latest study, the researchers gave fruit flies doses of lithium, trametinib and rapamycin, separately and in combination. Each drug individually extended lifespan by an average of 11%, while pairing two drugs extended lifespan by roughly 30%. When the three drugs were combined, the fruit flies lived 48% longer than flies in a control group that were not given the treatment.
"Previous studies in fruit flies have achieved lifespan extensions of about 5-20%, so we found it was quite remarkable that this drug combination enabled them to live 48% longer," Dr Castillo-Quan said.
The researchers found that in addition to acting on separate signalling pathways within the nutrient sensing network, the drugs also appear to complement each other to reduce side effects. Rapamycin has undesirable effects on fat metabolism, which can be similar to insulin resistance in people, but lithium appeared to cancel out this effect when the two drugs were given together.
The researchers will continue their research to better understand exactly how the drugs work in combination with each other, and hope to progress to experiments in more complex animals, such as mice, to gauge the effects on the entire body before eventually progressing to human trials.
Principal investigator, Professor Linda Partridge (UCL Institute of Health Ageing and Max Planck Institute for Biology of Ageing), said: "There is a growing body of evidence that polypills -- pills that combine low doses of multiple pharmaceutical products -- could be effective as a medication to prevent age-related diseases, given the complex nature of the ageing process. This may be possible by combining the drugs we're investigating with other promising drugs, but there is a long way to go before we will be able to roll out effective treatments."
"My research groups are working to understand the mechanism of the ageing process in order to find ways to help people stay healthy for longer. We are not trying to cheat death, but help people be healthy and disease-free in their final years," she said.
Read more at Science Daily
Brave new world: Simple changes in intensity of weather events 'could be lethal'
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| Palm trees in heavy weather. |
Faced with unprecedented change, animals and plants are scrambling to catch up -- with mixed results. A new model developed by Carlos Botero, assistant professor of biology in Arts & Sciences, and Thomas Haaland, formerly a graduate student at the Norwegian University of Science and Technology, helps to predict the types of changes that could drive a given species to extinction.
The study, published Sept. 27 in the journal Ecology and Evolution, challenges the idea that species previously exposed to more variable conditions are more likely to survive extreme events.
"It is difficult to predict how organisms will respond to changes in extreme events because these events tend to be, by definition, quite rare," Botero said. "But we can have a pretty good idea of how any given species may respond to current changes in this aspect of climate -- if we pay attention to its natural history, and have some idea of the climatic regime it has experienced in the past."
Unexpected vulnerabilities
Researchers in the Botero laboratory use a variety of tools from ecology and evolutionary biology to explore how life -- from bacteria to humans -- copes with and adapts to repeated environmental change.
For the new study, Botero worked with his former student Haaland, now a postdoctoral fellow at the University of Zurich in Switzerland, to develop an evolutionary model of how populations respond to rare environmental extremes. (Think: 500-year floods.) These rare events can be tricky for evolution because it is difficult to adapt to hazards that are almost never encountered.
Through computer simulations, Haaland and Botero found that certain traits and experiences emerged as key indicators of vulnerability.
Specifically, they found:
- Species that breed a single time in their lifetime tend to evolve conservative behaviors or morphologies, as if they were expecting to experience an environmental extreme every time.
- In contrast, species in which a single individual can reproduce multiple times and in different contexts (say, a bird that nests several times in a season and in different trees), evolution favors behaving as if environmental extremes simply never happen.
The key insight of this new model is that species belonging to the former, "conservative" category can easily adapt to more frequent or widespread extremes but have trouble adjusting when those extremes become more intense. The opposite is true of species in the latter, "care-free" category.
Haaland and Botero also found that factors speeding up trait evolution are generally likely to hinder -- rather than favor -- adaptation to rare selection events. Part of the reason: High mutation rates tend to facilitate the process of adaptation to normal conditions during the long intervals in between environmental extremes.
"Our results challenge the idea that species that have been historically exposed to more variable environments are better suited to cope with climate change," Botero said.
"We see that simple changes in the pattern and intensity of environmental extremes could be lethal even for populations that have experienced similar events in the past. This model simply helps us better understand when and where we may have a problem."
Applicable to many environmental extremes
The simple framework that Haaland and Botero describe can be applied to any kind of environmental extreme including flooding, wildfires, heatwaves, droughts, cold spells, tornadoes and hurricanes -- any and all of which might be considered part of the "new normal" under climate change.
Take extreme heat as an example. The model can be used to predict what will happen to animal or plant species when there are more heat waves, when heatwaves last longer, or when typical heat waves affect larger areas.
"Regions in which heat waves used to be rare and patchy are likely to host primarily species that do not exhibit conspicuous adaptations to extreme heat," Botero said. "Our model indicates that the biggest threats of extinction in these particular locations will therefore be more frequent or widespread heat waves, and that the species of highest concern in these places will be endemics and species with small geographic distribution.
"Conversely, areas in which heat waves were historically common and widespread can be expected to host species that already exhibit adaptations for extreme heat," Botero added. "In this case, our model suggests that the typical inhabitants of these places are likely to be more vulnerable to hotter temperatures than to longer or more widespread heat waves."
Informing conservation actions
The new model gives wildlife managers and conservation organizations insight into the potential vulnerabilities of different species based on relatively simple assessments of their natural histories and historical environments.
For example, a 2018 study by Colin Donihue, visiting postdoctoral fellow at Washington University, found that Anolis lizards in the Caribbean tend to evolve larger toepads and shorter limb lengths in response to hurricanes because these traits help them cling better to branches during strong winds. The new model suggests that while these lizards are unlikely to be affected by more frequent hurricanes, their populations may nevertheless face a significant threat of extinction if future hurricanes become more intense. A possible solution to this problem might be to provide wind refuges across the island to allow parts of the population escape winds of very high intensity, Botero suggested.
Read more at Science Daily
Molecular basis of vision revealed
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| Closeup of eye |
The findings illuminate how signals from photons (particles of light) get amplified in the eye. More importantly, the study provides insights into how the largest family of cell membrane proteins -- G-protein-coupled receptors (GPCRs) -- work in humans.
"They're involved in almost all the biological processes in a human body -- how we perceive light, taste, smell, or how the heart rate is regulated or muscles contract -- and they are targets for over 30% of the drugs that are used today," said Yang Gao, co-first author of the paper and a postdoctoral researcher in the lab of Richard Cerione, the Goldwin Smith Professor of Chemistry and Chemical Biology and co-senior author.
There are over 800 GPCRs in humans that signal through about 20 different G proteins. GPCRs are responsible for sensing a wide range of outside signals -- such as hormones, light, and sense of smell and taste -- and inducing corresponding responses inside the cell. In vertebrate vision, the GPCR rhodopsin is capable of detecting the signal from just one photon and through the activation of the G protein transducin and downstream effectors, amplify it 100,000 times.
The researchers used cryo-electron microscopy to obtain atomic-resolution structures of the rhodopsin-transducin complex. The structures not only provide the molecular basis of vertebrate vision, but also reveal a previously unknown mechanism of how GPCRs in general activate G proteins.
"What we've learnt from these structures at an atomic level may be broadly applicable to other GPCR signaling systems," said co-first author Sekar Ramachandran, a senior research associate in Cerione's lab.
By learning more about how different receptors specifically couple with different G proteins, the researchers hope to gain insights into designing drugs that specifically regulate GPCR signaling. A lot of drug side effects occur when therapies are not specific enough and target both harmful and beneficial pathways, Yang said.
Read more at Science Daily
Sep 30, 2019
Insight into competitive advantage of modern humans over Neanderthals
A team of Japanese and Italian researchers, including from Tohoku University, have evidenced mechanically delivered projectile weapons in Europe dating to 45,000-40,000 years -- more than 20,000 years than previously thought. This study, entitled "The earliest evidence for mechanically delivered projectile weapons in Europe" published in Nature Ecology & Evolution, indicated that the spearthrower and bow-and-arrow technologies allowed modern humans to hunt more successfully than Neanderthals -- giving them a competitive advantage. This discovery offered important insight to understand the reasons for the replacement of Neanderthals by modern humans.
Apparently, Neanderthals and modern humans coexisted in Europe for at least 5,000 years. However, little is known about why modern humans could increase their population size after migrating to Europe and successfully occupy new territories, while autochthonous Neanderthals went extinct ~ 40,000 years ago.
The research team included 17 scientists from Italy and Japan, coordinated by the archaeologists Katsuhiro Sano (Center for Northeast Asian Studies, Tohoku University) and Adriana Moroni (Department of Environment, Earth and Physical Sciences, University of Siena), and the paleoanthropologist Stefano Benazzi (Department of Cultural Heritage, University of Bologna).
They studied 146 crescent-shaped backed pieces (also referred to as lunates or segments) retrieved from the Uluzzian culture of Grotta del Cavallo (Southern Italy), the first Upper Paleolithic culture developed by modern humans in Europe. "Similar backed pieces have been observed in East Africa, although there is no archaeological evidence indicating a route from East Africa into Europe. To better understand the differences in the Uluzzian from previous lithic traditions, as well as the significance of the emergence of this new culture in Europe, it was crucial to identify the function of the backed pieces," said Adriana Moroni.
The backed pieces were macroscopically and microscopically analyzed using a Hirox digital microscope and results were compared with use-wear patterns on experimental samples. Through this analysis, diagnostic impact fractures and microscopic impact linear traces were found on numerous backed pieces, demonstrating that they were used as hunting weapons. "The diagnostic impact fractures showed the similar patterns of experimental samples delivered by a spearthrower and a bow, but significantly different from those observed on throwing and thrusting samples," said Katsuhiro Sano. "Modern humans migrating into Europe equipped themselves with mechanically delivered projectile weapons, such as a spearthrower-darts or a bow-and-arrows, which had higher impact energy hunting strategy and offered modern humans a substantive advantage over Neanderthals," concluded Sano.
Furthermore, fourier transform-infrared (FTIR) spectromicroscopy of residues on several pieces demonstrate that the backed pieces were hafted using a complex adhesive, including ochre, plant gum, and beeswax, which stabilized the hafting. "Comparison with FTIR spectroscopy analyses of several red deposit and soil samples recovered from Grotta del Cavallo ruled out organic contaminants from the burial environment and confirmed the presence of ochre as a mixture of silicate and iron oxides," said Chiaramaria Stani (Elettra-Sincrotrone Trieste).
Read more at Science Daily
Apparently, Neanderthals and modern humans coexisted in Europe for at least 5,000 years. However, little is known about why modern humans could increase their population size after migrating to Europe and successfully occupy new territories, while autochthonous Neanderthals went extinct ~ 40,000 years ago.
The research team included 17 scientists from Italy and Japan, coordinated by the archaeologists Katsuhiro Sano (Center for Northeast Asian Studies, Tohoku University) and Adriana Moroni (Department of Environment, Earth and Physical Sciences, University of Siena), and the paleoanthropologist Stefano Benazzi (Department of Cultural Heritage, University of Bologna).
They studied 146 crescent-shaped backed pieces (also referred to as lunates or segments) retrieved from the Uluzzian culture of Grotta del Cavallo (Southern Italy), the first Upper Paleolithic culture developed by modern humans in Europe. "Similar backed pieces have been observed in East Africa, although there is no archaeological evidence indicating a route from East Africa into Europe. To better understand the differences in the Uluzzian from previous lithic traditions, as well as the significance of the emergence of this new culture in Europe, it was crucial to identify the function of the backed pieces," said Adriana Moroni.
The backed pieces were macroscopically and microscopically analyzed using a Hirox digital microscope and results were compared with use-wear patterns on experimental samples. Through this analysis, diagnostic impact fractures and microscopic impact linear traces were found on numerous backed pieces, demonstrating that they were used as hunting weapons. "The diagnostic impact fractures showed the similar patterns of experimental samples delivered by a spearthrower and a bow, but significantly different from those observed on throwing and thrusting samples," said Katsuhiro Sano. "Modern humans migrating into Europe equipped themselves with mechanically delivered projectile weapons, such as a spearthrower-darts or a bow-and-arrows, which had higher impact energy hunting strategy and offered modern humans a substantive advantage over Neanderthals," concluded Sano.
Furthermore, fourier transform-infrared (FTIR) spectromicroscopy of residues on several pieces demonstrate that the backed pieces were hafted using a complex adhesive, including ochre, plant gum, and beeswax, which stabilized the hafting. "Comparison with FTIR spectroscopy analyses of several red deposit and soil samples recovered from Grotta del Cavallo ruled out organic contaminants from the burial environment and confirmed the presence of ochre as a mixture of silicate and iron oxides," said Chiaramaria Stani (Elettra-Sincrotrone Trieste).
Read more at Science Daily
Preserving old bones with modern technology
A team of University of Colorado Boulder anthropologists is out to change the way that scientists study old bones damage-free.
If that sounds like a macabre goal, consider this: Bits of well-preserved bones are valuable to researchers studying humans who lived thousands to hundreds of thousands of years ago.
These samples sometimes contain collagen, a useful molecule than can reveal a wealth of information about human remains -- from how long ago a person died to what he or she may have eaten.
"Bone collagen is really a treasure within the realm of archaeology," said Christina Ryder, a graduate student in the Department of Anthropology at CU Boulder.
Now, she and her colleagues have come up with a creative way to be thrifty with that treasure.
In research published this week in the journal Scientific Reports, the group describes a new method for screening bone samples to see if they contain collagen. Unlike existing tools that look for that type of tissue, the team's approach won't damage the bones in the process.
For anthropologists, the test could be "a game changer," said study coauthor Matt Sponheimer, a professor of anthropology at CU Boulder.
"These remains have lain intact for thousands of years, so it always hurts a little bit to destroy a sample," he said. "It's doubly tragic if you do it, and it's all in vain. That's what we're trying to prevent."
It's a goal that emerged out of many hours of frustration. Several years ago, one of Sponheimer's colleagues was tasked with extracting collagen from a series of ancient bone samples. Collagen within bones is a bit like a birth certificate; if scientists can find enough of it, they can use collagen to determine the age of a human specimen through radiocarbon dating.
But this material, which helps to hold together human bones and other tissue, also doesn't age well. Many skeletal remains, even those from well-preserved graves, don't contain much of it.
"My student was spending weeks and, ultimately, months of lab time trying to get dietary info from ancient collagen, and it was working incredibly poorly," Sponheimer said. "I thought to myself, 'There has to be a better way.'"
As it turns out, there was. In their latest study, Sponheimer, Ryder and their colleagues discovered that they could calibrate a machine called a near-infrared spectrometer to test bones for the presence of collagen.
The process is surprisingly easy, Ryder said. The instrument, which operates by way of a handheld probe, scans samples of bone and then -- in a matter of seconds -- churns out an estimate of how much collagen is inside.
"I'll tease that the longest part of the process is typing in the file name," Ryder said.
To make sure that their method was accurate, the researchers tested their instrument on more than 50 samples of ground-up bone with known concentrations of collagen. The tests correctly predicted the approximate concentrations of collagen within each of those samples. It worked with 44 pieces of whole bone, too.
Ryder added that the entire spectrometer is about the size of a briefcase, which means that the team can carry it with them into the field.
It's already gone through one high-profile dry run. Last year, Ryder flew to Germany to meet with colleagues at the Max Planck Institute for Evolutionary Anthropology. The researchers wanted to date human remains uncovered from Dolni Vestonice -- a one-of-a-kind archaeological site in the Czech Republic that hosts some of the oldest known examples of representational art in human history.
"The grad student on this project had only six vials of samples from human burials," Ryder said. "That was all she had, and that was all anyone was going to have for the foreseeable future."
Read more at Science Daily
If that sounds like a macabre goal, consider this: Bits of well-preserved bones are valuable to researchers studying humans who lived thousands to hundreds of thousands of years ago.
These samples sometimes contain collagen, a useful molecule than can reveal a wealth of information about human remains -- from how long ago a person died to what he or she may have eaten.
"Bone collagen is really a treasure within the realm of archaeology," said Christina Ryder, a graduate student in the Department of Anthropology at CU Boulder.
Now, she and her colleagues have come up with a creative way to be thrifty with that treasure.
In research published this week in the journal Scientific Reports, the group describes a new method for screening bone samples to see if they contain collagen. Unlike existing tools that look for that type of tissue, the team's approach won't damage the bones in the process.
For anthropologists, the test could be "a game changer," said study coauthor Matt Sponheimer, a professor of anthropology at CU Boulder.
"These remains have lain intact for thousands of years, so it always hurts a little bit to destroy a sample," he said. "It's doubly tragic if you do it, and it's all in vain. That's what we're trying to prevent."
It's a goal that emerged out of many hours of frustration. Several years ago, one of Sponheimer's colleagues was tasked with extracting collagen from a series of ancient bone samples. Collagen within bones is a bit like a birth certificate; if scientists can find enough of it, they can use collagen to determine the age of a human specimen through radiocarbon dating.
But this material, which helps to hold together human bones and other tissue, also doesn't age well. Many skeletal remains, even those from well-preserved graves, don't contain much of it.
"My student was spending weeks and, ultimately, months of lab time trying to get dietary info from ancient collagen, and it was working incredibly poorly," Sponheimer said. "I thought to myself, 'There has to be a better way.'"
As it turns out, there was. In their latest study, Sponheimer, Ryder and their colleagues discovered that they could calibrate a machine called a near-infrared spectrometer to test bones for the presence of collagen.
The process is surprisingly easy, Ryder said. The instrument, which operates by way of a handheld probe, scans samples of bone and then -- in a matter of seconds -- churns out an estimate of how much collagen is inside.
"I'll tease that the longest part of the process is typing in the file name," Ryder said.
To make sure that their method was accurate, the researchers tested their instrument on more than 50 samples of ground-up bone with known concentrations of collagen. The tests correctly predicted the approximate concentrations of collagen within each of those samples. It worked with 44 pieces of whole bone, too.
Ryder added that the entire spectrometer is about the size of a briefcase, which means that the team can carry it with them into the field.
It's already gone through one high-profile dry run. Last year, Ryder flew to Germany to meet with colleagues at the Max Planck Institute for Evolutionary Anthropology. The researchers wanted to date human remains uncovered from Dolni Vestonice -- a one-of-a-kind archaeological site in the Czech Republic that hosts some of the oldest known examples of representational art in human history.
"The grad student on this project had only six vials of samples from human burials," Ryder said. "That was all she had, and that was all anyone was going to have for the foreseeable future."
Read more at Science Daily
Purple martin migration behavior perplexes researchers
Purple martins will soon migrate south for their usual wintertime retreat, but this time the birds will be wearing what look like little backpacks, as scientists plan to track their roosting sites along the way.
The researchers recently discovered that purple martins are roosting in small forest patches as they migrate from North America to Brazil. The scientists published their findings in the Journal of Field Ornithology.
"This is highly unusual behavior for songbirds, which typically roost in heavily forested areas," said Auriel Fournier, a co-author of the study with University of Manitoba biological sciences professor Kevin Fraser, who led the research. Fournier is the director of the Forbes Biological Station at the Illinois Natural History Survey.
"It's surprising to see them roosting in these forest islands, which are small, isolated clusters of trees typically surrounded by agriculture, water or recently cut forest," Fournier said.
The researchers want to determine whether the birds are responding to a change in the environment or whether their surprising roosting behavior is something purple martins have always done.
"We believe they must be intentionally seeking out the forest islands," Fournier said. "Because these habitats don't occur very frequently on the landscape, the birds' use of them is unlikely to be by chance."
"We are curious if birds are choosing these isolated patches of habitat because they have fewer predators than in larger patches of forest," Fraser said.
About 13% of the world's birds are colonial nesters, and purple martins are the only songbird species that requires a nest site surrounded by the nests of other similar birds, the researchers said.
"During migration, these birds flock in numbers up to the hundreds of thousands," Fournier said. "It's wild because their flocks are sometimes big enough to be detected by radar."
The researchers had to wait for technology to catch up before they could identify precisely where the birds were stopping to rest during migration. A purple martin weighs about 1.6 ounces (45 grams) and flies an estimated 6,200 to 13,700 miles (10,000 to 22,0000 kilometers) a year. Too much additional weight -- even that of a tiny tracker, for example -- could interfere with the bird's trek.
Thanks to advances in technology, the scientists are using GPS tracking devices small enough to be carried by purple martins. The devices use satellites to pinpoint the birds' location with such accuracy that Fraser and Fournier can identify down to a single tree where a tagged purple martin is roosting at night during migration.
"No one has looked at habitats during migration," Fraser said. "But we need to look so that we can start protecting these birds and their habitats across international boundaries."
Read more at Science Daily
The researchers recently discovered that purple martins are roosting in small forest patches as they migrate from North America to Brazil. The scientists published their findings in the Journal of Field Ornithology.
"This is highly unusual behavior for songbirds, which typically roost in heavily forested areas," said Auriel Fournier, a co-author of the study with University of Manitoba biological sciences professor Kevin Fraser, who led the research. Fournier is the director of the Forbes Biological Station at the Illinois Natural History Survey.
"It's surprising to see them roosting in these forest islands, which are small, isolated clusters of trees typically surrounded by agriculture, water or recently cut forest," Fournier said.
The researchers want to determine whether the birds are responding to a change in the environment or whether their surprising roosting behavior is something purple martins have always done.
"We believe they must be intentionally seeking out the forest islands," Fournier said. "Because these habitats don't occur very frequently on the landscape, the birds' use of them is unlikely to be by chance."
"We are curious if birds are choosing these isolated patches of habitat because they have fewer predators than in larger patches of forest," Fraser said.
About 13% of the world's birds are colonial nesters, and purple martins are the only songbird species that requires a nest site surrounded by the nests of other similar birds, the researchers said.
"During migration, these birds flock in numbers up to the hundreds of thousands," Fournier said. "It's wild because their flocks are sometimes big enough to be detected by radar."
The researchers had to wait for technology to catch up before they could identify precisely where the birds were stopping to rest during migration. A purple martin weighs about 1.6 ounces (45 grams) and flies an estimated 6,200 to 13,700 miles (10,000 to 22,0000 kilometers) a year. Too much additional weight -- even that of a tiny tracker, for example -- could interfere with the bird's trek.
Thanks to advances in technology, the scientists are using GPS tracking devices small enough to be carried by purple martins. The devices use satellites to pinpoint the birds' location with such accuracy that Fraser and Fournier can identify down to a single tree where a tagged purple martin is roosting at night during migration.
"No one has looked at habitats during migration," Fraser said. "But we need to look so that we can start protecting these birds and their habitats across international boundaries."
Read more at Science Daily
Black holes and their host galaxies, growing old together
Some relationships are written in the stars. That's definitely the case for supermassive black holes and their host galaxies, according to a new study from Yale University. The "special relationship" between supermassive black holes (SMBHs) and their hosts -- something astronomers and physicists have observed for quite a while -- can now be understood as a bond that begins early in a galaxy's formation and has a say in how both the galaxy and the SMBH at its center grow over time, the researchers note.
A black hole is a point in space where matter has been compacted so tightly that it creates intense gravity. This gravity is strong enough that even light can't escape its pull. Black holes can be as small as a single atom or as large as billions of miles in diameter. The biggest are called "supermassive" black holes and have masses equal to that of millions -- or even billions -- of suns.
SMBHs are often found at the center of large galaxies, including our own galaxy, the Milky Way. Although SMBHs were theoretically expected to exist, the first observational hints were detected in the 1960s; earlier this year, the Event Horizon Telescope released the first silhouette of a black hole in the galaxy Messier 87. Astrophysicists continue to theorize about the origins of black holes, how they grow and glow, and how they interact with host galaxies in different astronomical environments.
"There has been a lot of uncertainty regarding the SMBH-galaxy connection, in particular whether SMBH growth was more tightly connected to the star formation rate or the mass of the host galaxy," said Yale astrophysicist Priyamvada Natarajan, senior investigator of the new study, which appears in the journal Monthly Notices of the Royal Astronomical Society. "These results represent the most thorough theoretical evidence for the former -- the growth rate of black holes appears to be tightly coupled to the rate at which stars form in the host."
Natarajan has made significant contributions to our understanding of the formation, assembly, and growth of SMBHs, with respect to their environs. Her work speaks to the underlying question of whether these connections are mere correlations or signs of deeper causation.
Natarajan and her team -- first author Angelo Ricarte and Michael Tremmel of Yale and Thomas Quinn of the University of Washington -- used sophisticated sets of simulations to make the discovery. Called Romulus, the cosmological simulation follows the evolution of different regions of the universe from just after the Big Bang until the present day and includes thousands of simulated galaxies that reside in a wide variety of cosmic environments.
The Romulus simulations offer the highest-resolution snapshot of black hole growth, providing a fully emergent and sharper view of how black holes grow within a wide range of host galaxies, from the most massive galaxies located in the center of galaxy clusters -- very dense regions like crowded city centers -- to much more common dwarf galaxies that inhabit the sparser suburbs.
"At a time when the drivers of black hole growth are unclear, these simulations offer a simple picture. They simply grow along with the stars independent of the galaxy's mass, the larger environment, or the cosmic epoch," said Ricarte, a former graduate student of Natarajan's who is now a postdoctoral fellow at Harvard.
One of the more intriguing findings of the study, Ricarte noted, has to do with the way the largest black holes in the universe interact with their host galaxies over time. The researchers found that SMBHs and their hosts grow in tandem, and that the relationship is "self-correcting," independent of the kind of environment they inhabit.
"If the SMBH starts to grow too rapidly and gets too big for its galactic home, physical processes ensure that its growth slows down relative to the galaxy," Tremmel explained. "On the other hand, if the SMBH's mass is too small for its galaxy, the SMBH's growth rate increases relative to the size of the galaxy to compensate."
Read more at Science Daily
A black hole is a point in space where matter has been compacted so tightly that it creates intense gravity. This gravity is strong enough that even light can't escape its pull. Black holes can be as small as a single atom or as large as billions of miles in diameter. The biggest are called "supermassive" black holes and have masses equal to that of millions -- or even billions -- of suns.
SMBHs are often found at the center of large galaxies, including our own galaxy, the Milky Way. Although SMBHs were theoretically expected to exist, the first observational hints were detected in the 1960s; earlier this year, the Event Horizon Telescope released the first silhouette of a black hole in the galaxy Messier 87. Astrophysicists continue to theorize about the origins of black holes, how they grow and glow, and how they interact with host galaxies in different astronomical environments.
"There has been a lot of uncertainty regarding the SMBH-galaxy connection, in particular whether SMBH growth was more tightly connected to the star formation rate or the mass of the host galaxy," said Yale astrophysicist Priyamvada Natarajan, senior investigator of the new study, which appears in the journal Monthly Notices of the Royal Astronomical Society. "These results represent the most thorough theoretical evidence for the former -- the growth rate of black holes appears to be tightly coupled to the rate at which stars form in the host."
Natarajan has made significant contributions to our understanding of the formation, assembly, and growth of SMBHs, with respect to their environs. Her work speaks to the underlying question of whether these connections are mere correlations or signs of deeper causation.
Natarajan and her team -- first author Angelo Ricarte and Michael Tremmel of Yale and Thomas Quinn of the University of Washington -- used sophisticated sets of simulations to make the discovery. Called Romulus, the cosmological simulation follows the evolution of different regions of the universe from just after the Big Bang until the present day and includes thousands of simulated galaxies that reside in a wide variety of cosmic environments.
The Romulus simulations offer the highest-resolution snapshot of black hole growth, providing a fully emergent and sharper view of how black holes grow within a wide range of host galaxies, from the most massive galaxies located in the center of galaxy clusters -- very dense regions like crowded city centers -- to much more common dwarf galaxies that inhabit the sparser suburbs.
"At a time when the drivers of black hole growth are unclear, these simulations offer a simple picture. They simply grow along with the stars independent of the galaxy's mass, the larger environment, or the cosmic epoch," said Ricarte, a former graduate student of Natarajan's who is now a postdoctoral fellow at Harvard.
One of the more intriguing findings of the study, Ricarte noted, has to do with the way the largest black holes in the universe interact with their host galaxies over time. The researchers found that SMBHs and their hosts grow in tandem, and that the relationship is "self-correcting," independent of the kind of environment they inhabit.
"If the SMBH starts to grow too rapidly and gets too big for its galactic home, physical processes ensure that its growth slows down relative to the galaxy," Tremmel explained. "On the other hand, if the SMBH's mass is too small for its galaxy, the SMBH's growth rate increases relative to the size of the galaxy to compensate."
Read more at Science Daily
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