Color awareness has long been a puzzle for researchers in neuroscience and psychology, who debate over how much color observers really perceive. A study from Dartmouth in collaboration with Amherst College finds that people are aware of surprisingly limited color in their peripheral vision; much of our sense of a colorful visual world is likely constructed by our brain. The findings are published in the Proceedings of the National Academy of Sciences .
To test people's visual awareness of color during naturalistic viewing, the researchers used head-mounted virtual reality displays installed with eye-trackers to immerse participants in a 360-degree real-world environment. The virtual environments included tours of historic sites, a street dance performance, a symphony rehearsal and more, where observers could explore their surroundings simply by turning their heads. With the eye-tracking tool, researchers knew exactly where an observer was looking at all times in the scene and could make systematic changes to the visual environment so that only the areas where the person was looking were in color. The rest of the scene in the periphery was desaturated so that it had no color and was just in black and white. After a series of trials, observers were asked a series of questions to gauge if they noticed the lack of color in their periphery. A supplemental video from the study illustrates how the peripheral color was removed from various scenes.
In your visual field, your periphery extends approximately 210 degrees, which is similar to if your arms are stretched out on your left and right. The study's results showed that most people's color awareness is limited to a small area around the dead center of their visual field. When the researchers removed most color in the periphery, most people did not notice. In the most extreme case, almost a third of observers did not notice when less than five percent of the entire visual field was presented in color (radius of 10 degrees visual angle).
Participants were astonished to find out later that they hadn't noticed the desaturated periphery, after they were shown the changes that were made to a virtual scene that they had just explored.
A second study tasked the participants to identify when color was desaturated in the periphery. The results were similar in that most people failed to notice when the peripheral color had been removed. A large number of people participated in the two studies, which featured nearly 180 participants in total.
"We were amazed by how oblivious participants were when color was removed from up to 95 percent of their visual world," said senior author, Caroline Robertson, an assistant professor of psychological and brain sciences at Dartmouth. "Our results show that our intuitive sense of a rich, colorful visual world is largely incorrect. Our brain is likely filling-in much of our perceptual experience."
Read more at Science Daily
Jun 13, 2020
Scientists uncover immune cells that may lower airway allergy and asthma risk
The world is full of house dust mites. Do some cleaning, and you'll probably stir some up. While everyone has immune cells capable of reacting to common allergens like house dust mites, most of us have no allergic symptoms.
Still, many people do react with the typical allergic symptoms: sneezing, a runny nose, and itchy, swollen nasal passages. Others have a much more severe reaction: a life-threatening asthma attack.
To treat the root cause of allergies and asthma, researchers need to know exactly what sets these patients apart from healthy individuals.
In a new Science Immunology study, published on June 12, 2020, scientists at La Jolla Institute for Immunology (LJI) offer a clue to why non-allergic people don't have a strong reaction to house dust mites. They've uncovered a previously unknown subset of T cells that may control allergic immune reactions and asthma from ever developing in response to house dust mites -- and other possible allergens.
"We discovered new immune cell subsets and new therapeutic opportunities," says Grégory Seumois, Ph.D., instructor and director of LJI's Sequencing Core and co-leader of the new study. "This new population of cells could be one, out of many unknown mechanisms, that explains why healthy people don't develop inflammation when they breathe in allergens."
"The study highlights the power of unbiased single-cell genomics approaches to uncover novel biology," says LJI Professor Pandurangan Vijayanand, M.D. Ph.D., senior author of the new study.
The study builds on the Vijayanand lab's expertise in linking gene expression to disease development. The team also took advantage of the Immune Epitope Database, an LJI-led resource that houses information on how the immune system interacts with allergens like house dust mites.
Why house dust mites? These microscopic critters are hard to avoid, which means nearly everyone has been exposed. Even in people without a house dust mite (HDM) allergy, the immune system is likely to react in some way as it learns to recognize HDM molecules. This makes HDM a useful model for studying what causes allergies and asthma attacks.
The LJI team used a technique part of the "genomic revolution" arsenal of tools, called single-cell RNA-seq (or single cell transcriptomics) to see exactly which genes and molecules specific T cells produce in response to HDM allergens. They tested cells from four groups of people: people with asthma and HDM allergy, people with asthma but no HDM allergy, people with only HDM allergy, and healthy subjects.
Their analysis suggests that a subset of helper T cells, called interleukin (IL)-9 Th2 expressing HDM-reactive cells, is more prevalent in the blood of people with HDM-allergic asthma compared with those who are only allergic to HDM. Further analysis suggested that those IL9-TH2 cells are enriched in a group of molecules/genes that increased the cytotoxic potential of those cells. In other words, those specific T cells could kill other cells and drive inflammation.
In contrast, another subset of T cells stood out in the non-allergic subjects. These T cells express an "interferon response signature" and were enriched for a gene that encodes a protein called TRAIL. The work done by Seumois and his colleagues suggest that TRAIL could be important because it could dampen the activation of helper T cells.
This finding may mean that people with this specific cell population could have less T-cell driven inflammation in response to HDM allergens. At last, this could provide a clue to why some people develop allergies and asthma while others do not.
"Now if functional studies confirm this dampening effect, we're curious if there is a way to boost the activation of these T cells or induce their proliferation in asthmatic or allergic populations," says Seumois. "Can we act on those cells very early on, before asthma has developed?"
For example, genomics studies like this one may someday help identify children at risk of developing asthma and allergies. Early detection could open the door to preemptively acting on immune cells before development of allergy and asthma.
Read more at Science Daily
Still, many people do react with the typical allergic symptoms: sneezing, a runny nose, and itchy, swollen nasal passages. Others have a much more severe reaction: a life-threatening asthma attack.
To treat the root cause of allergies and asthma, researchers need to know exactly what sets these patients apart from healthy individuals.
In a new Science Immunology study, published on June 12, 2020, scientists at La Jolla Institute for Immunology (LJI) offer a clue to why non-allergic people don't have a strong reaction to house dust mites. They've uncovered a previously unknown subset of T cells that may control allergic immune reactions and asthma from ever developing in response to house dust mites -- and other possible allergens.
"We discovered new immune cell subsets and new therapeutic opportunities," says Grégory Seumois, Ph.D., instructor and director of LJI's Sequencing Core and co-leader of the new study. "This new population of cells could be one, out of many unknown mechanisms, that explains why healthy people don't develop inflammation when they breathe in allergens."
"The study highlights the power of unbiased single-cell genomics approaches to uncover novel biology," says LJI Professor Pandurangan Vijayanand, M.D. Ph.D., senior author of the new study.
The study builds on the Vijayanand lab's expertise in linking gene expression to disease development. The team also took advantage of the Immune Epitope Database, an LJI-led resource that houses information on how the immune system interacts with allergens like house dust mites.
Why house dust mites? These microscopic critters are hard to avoid, which means nearly everyone has been exposed. Even in people without a house dust mite (HDM) allergy, the immune system is likely to react in some way as it learns to recognize HDM molecules. This makes HDM a useful model for studying what causes allergies and asthma attacks.
The LJI team used a technique part of the "genomic revolution" arsenal of tools, called single-cell RNA-seq (or single cell transcriptomics) to see exactly which genes and molecules specific T cells produce in response to HDM allergens. They tested cells from four groups of people: people with asthma and HDM allergy, people with asthma but no HDM allergy, people with only HDM allergy, and healthy subjects.
Their analysis suggests that a subset of helper T cells, called interleukin (IL)-9 Th2 expressing HDM-reactive cells, is more prevalent in the blood of people with HDM-allergic asthma compared with those who are only allergic to HDM. Further analysis suggested that those IL9-TH2 cells are enriched in a group of molecules/genes that increased the cytotoxic potential of those cells. In other words, those specific T cells could kill other cells and drive inflammation.
In contrast, another subset of T cells stood out in the non-allergic subjects. These T cells express an "interferon response signature" and were enriched for a gene that encodes a protein called TRAIL. The work done by Seumois and his colleagues suggest that TRAIL could be important because it could dampen the activation of helper T cells.
This finding may mean that people with this specific cell population could have less T-cell driven inflammation in response to HDM allergens. At last, this could provide a clue to why some people develop allergies and asthma while others do not.
"Now if functional studies confirm this dampening effect, we're curious if there is a way to boost the activation of these T cells or induce their proliferation in asthmatic or allergic populations," says Seumois. "Can we act on those cells very early on, before asthma has developed?"
For example, genomics studies like this one may someday help identify children at risk of developing asthma and allergies. Early detection could open the door to preemptively acting on immune cells before development of allergy and asthma.
Read more at Science Daily
Jun 12, 2020
What control the height of mountains? Surprisingly, it is not erosion
Which forces and mechanisms determine the height of mountains? A group of researchers from Münster and Potsdam has now found a surprising answer: It is not erosion and weathering of rocks that determine the upper limit of mountain massifs, but rather an equilibrium of forces in the Earth's crust. This is a fundamentally new and important finding for the earth sciences. The researchers report on it in the scientific journal Nature.
The highest mountain ranges on Earth -- such as the Himalayas or the Andes -- arise along convergent plate boundaries. At such plate boundaries two tectonic plates move toward each other, and one of the plates is forced beneath the other into the Earth's mantle. During this process of subduction, strong earthquakes repeatedly occur on the plate interface, and over millions of years mountain ranges are built at the edges of the continents.
Whether the height of mountain ranges is mainly determined by tectonic processes in the Earth's interior or by erosional processes sculpturing the Earth's surface has long been debated in geosciences.
A new study led by Armin Dielforder of GFZ German Research Centre for Geoscience now shows that erosion by rivers and glaciers has no significant influence on the height of mountain ranges. Together with scientists from the GFZ and the University of Münster (Germany), he resolved the longstanding debate by analysing the strength of various plate boundaries and calculating the forces acting along the plate interfaces.
The researchers arrived at this surprising result by calculating the forces along different plate boundaries on the Earth. They used data that provide information about the strength of plate boundaries. These data are derived, for example, from heat flow measurements in the subsurface. The heat flow at convergent plate boundaries is in turn influenced by the frictional energy at the interfaces of the continental plates.
One can imagine the formation of mountains using a tablecloth. If you place both hands under the cloth on the table top and push it, the cloth folds and at the same time it slides a little over the back of your hands. The emerging folds would correspond, for instance, to the Andes, the sliding over the back of the hands to the friction in the underground. Depending on the characteristics of the rock, tensions also build up in the deep underground which are discharged in severe earthquakes, especially in subduction zones.
The researchers collected worldwide data from the literature on friction in the subsurface of mountain ranges of different heights (Himalayas, Andes, Sumatra, Japan) and calculated the resulting stress and thus the forces that lead to the uplift of the respective mountains. In this way they showed that in active mountains the force on the plate boundary and the forces resulting from the weight and height of the mountains are in balance.
Read more at Science Daily
The highest mountain ranges on Earth -- such as the Himalayas or the Andes -- arise along convergent plate boundaries. At such plate boundaries two tectonic plates move toward each other, and one of the plates is forced beneath the other into the Earth's mantle. During this process of subduction, strong earthquakes repeatedly occur on the plate interface, and over millions of years mountain ranges are built at the edges of the continents.
Whether the height of mountain ranges is mainly determined by tectonic processes in the Earth's interior or by erosional processes sculpturing the Earth's surface has long been debated in geosciences.
A new study led by Armin Dielforder of GFZ German Research Centre for Geoscience now shows that erosion by rivers and glaciers has no significant influence on the height of mountain ranges. Together with scientists from the GFZ and the University of Münster (Germany), he resolved the longstanding debate by analysing the strength of various plate boundaries and calculating the forces acting along the plate interfaces.
The researchers arrived at this surprising result by calculating the forces along different plate boundaries on the Earth. They used data that provide information about the strength of plate boundaries. These data are derived, for example, from heat flow measurements in the subsurface. The heat flow at convergent plate boundaries is in turn influenced by the frictional energy at the interfaces of the continental plates.
One can imagine the formation of mountains using a tablecloth. If you place both hands under the cloth on the table top and push it, the cloth folds and at the same time it slides a little over the back of your hands. The emerging folds would correspond, for instance, to the Andes, the sliding over the back of the hands to the friction in the underground. Depending on the characteristics of the rock, tensions also build up in the deep underground which are discharged in severe earthquakes, especially in subduction zones.
The researchers collected worldwide data from the literature on friction in the subsurface of mountain ranges of different heights (Himalayas, Andes, Sumatra, Japan) and calculated the resulting stress and thus the forces that lead to the uplift of the respective mountains. In this way they showed that in active mountains the force on the plate boundary and the forces resulting from the weight and height of the mountains are in balance.
Read more at Science Daily
Half the earth relatively intact from global human influence
Roughly half of Earth's ice-free land remains without significant human influence, according to a study from a team of international researchers led by the National Geographic Society and the University of California, Davis.
The study, published in the journal Global Change Biology, compared four recent global maps of the conversion of natural lands to anthropogenic land uses to reach its conclusions. The more impacted half of Earth's lands includes cities, croplands, and places intensively ranched or mined.
"The encouraging takeaway from this study is that if we act quickly and decisively, there is a slim window in which we can still conserve roughly half of Earth's land in a relatively intact state," said lead author Jason Riggio, a postdoctoral scholar at the UC Davis Museum of Wildlife and Fish Biology.
The study, published June 5 on World Environment Day, aims to inform the upcoming global Convention on Biological Diversity -- the Conference of Parties 15. The historic meeting was scheduled to occur in China this fall but was postponed due to the coronavirus pandemic. Among the meeting's goals is to establish specific, and higher, targets for land and water protection.
Approximately 15 percent of the Earth's land surface and 10 percent of the oceans are currently protected in some form. However, led by organizations including Nature Needs Half and the Half-Earth Project, there have been bold global calls for governments to commit to protecting 30 percent of the land and water by 2030 and 50 percent by 2050.
Intact natural lands across the globe can help purify air and water, recycle nutrients, enhance soil fertility and retention, pollinate plants, and break down waste products. The value of maintaining these vital ecosystem services to the human economy has been placed in the trillions of U.S. dollars annually.
CONSERVATION AND COVID-19
The coronavirus pandemic now shaking the globe illustrates the importance of maintaining natural lands to separate animal and human activity. The leading scientific evidence points to the likelihood that SARS-CoV2, the virus that causes the disease COVID-19, is a zoonotic virus that jumped from animals to humans. Ebola, bird flu and SARS are other diseases known to have spilled over into the human population from nonhuman animals.
"Human risk to diseases like COVID-19 could be reduced by halting the trade and sale of wildlife, and minimizing human intrusion into wild areas," said senior author Andrew Jacobson, professor of GIS and conservation at Catawba College in North Carolina.
Jacobson said that regional and national land-use planning that identify and appropriately zone locations best suited to urban growth and agriculture could help control the spread of human development. Establishing protections for other landscapes, particularly those currently experiencing low human impacts, would also be beneficial.
FROM THE TUNDRA TO THE DESERT
Among the largest low-impact areas are broad stretches of boreal forests and tundra across northern Asia and North America and vast deserts like the Sahara in Africa and the Australian Outback. These areas tend to be colder and/or drier and less fit for agriculture.
"Though human land uses are increasingly threatening Earth's remaining natural habitats, especially in warmer and more hospitable areas, nearly half of Earth still remains in areas without large-scale intensive use," said co-author Erle Ellis, professor of geography at the University of Maryland-Baltimore County.
Areas having low human influence do not necessarily exclude people, livestock or sustainable management of resources. A balanced conservation response that addresses land sovereignty and weighs agriculture, settlement or other resource needs with the protection of ecosystem services and biodiversity is essential, the authors note.
Read more at Science Daily
The study, published in the journal Global Change Biology, compared four recent global maps of the conversion of natural lands to anthropogenic land uses to reach its conclusions. The more impacted half of Earth's lands includes cities, croplands, and places intensively ranched or mined.
"The encouraging takeaway from this study is that if we act quickly and decisively, there is a slim window in which we can still conserve roughly half of Earth's land in a relatively intact state," said lead author Jason Riggio, a postdoctoral scholar at the UC Davis Museum of Wildlife and Fish Biology.
The study, published June 5 on World Environment Day, aims to inform the upcoming global Convention on Biological Diversity -- the Conference of Parties 15. The historic meeting was scheduled to occur in China this fall but was postponed due to the coronavirus pandemic. Among the meeting's goals is to establish specific, and higher, targets for land and water protection.
Approximately 15 percent of the Earth's land surface and 10 percent of the oceans are currently protected in some form. However, led by organizations including Nature Needs Half and the Half-Earth Project, there have been bold global calls for governments to commit to protecting 30 percent of the land and water by 2030 and 50 percent by 2050.
Intact natural lands across the globe can help purify air and water, recycle nutrients, enhance soil fertility and retention, pollinate plants, and break down waste products. The value of maintaining these vital ecosystem services to the human economy has been placed in the trillions of U.S. dollars annually.
CONSERVATION AND COVID-19
The coronavirus pandemic now shaking the globe illustrates the importance of maintaining natural lands to separate animal and human activity. The leading scientific evidence points to the likelihood that SARS-CoV2, the virus that causes the disease COVID-19, is a zoonotic virus that jumped from animals to humans. Ebola, bird flu and SARS are other diseases known to have spilled over into the human population from nonhuman animals.
"Human risk to diseases like COVID-19 could be reduced by halting the trade and sale of wildlife, and minimizing human intrusion into wild areas," said senior author Andrew Jacobson, professor of GIS and conservation at Catawba College in North Carolina.
Jacobson said that regional and national land-use planning that identify and appropriately zone locations best suited to urban growth and agriculture could help control the spread of human development. Establishing protections for other landscapes, particularly those currently experiencing low human impacts, would also be beneficial.
FROM THE TUNDRA TO THE DESERT
Among the largest low-impact areas are broad stretches of boreal forests and tundra across northern Asia and North America and vast deserts like the Sahara in Africa and the Australian Outback. These areas tend to be colder and/or drier and less fit for agriculture.
"Though human land uses are increasingly threatening Earth's remaining natural habitats, especially in warmer and more hospitable areas, nearly half of Earth still remains in areas without large-scale intensive use," said co-author Erle Ellis, professor of geography at the University of Maryland-Baltimore County.
Areas having low human influence do not necessarily exclude people, livestock or sustainable management of resources. A balanced conservation response that addresses land sovereignty and weighs agriculture, settlement or other resource needs with the protection of ecosystem services and biodiversity is essential, the authors note.
Read more at Science Daily
Ancient crocodiles walked on two legs like dinosaurs
An international research team has been stunned to discover that some species of ancient crocodiles walked on their two hind legs like dinosaurs and measured over three metres in length.
University of Queensland palaeontologist Dr Anthony Romilio said the researchers first thought the similar-shaped fossilised footprints were from another ancient animal known as the pterosaurs.
"At one site, the footprints were initially thought to be made by a giant bipedal pterosaur walking on the mudflat, we now understand that these were bipedal crocodile prints," Dr Romilio said.
"The footprints measure around 24 centimetres, suggesting the track-makers had legs about the same height as human adult legs.
"These were long animals that we estimate were over three metres in length.
"And while footprints were everywhere on the site, there were no handprints."
The research team, led by Professor Kyung Soo Kim from Chinju National University of Education, soon found clues as to why there were no handprints.
"Typical crocodiles walk in a squat stance and create trackways that are wide," Professor Kim said.
"Oddly, our trackways are very narrow looking -- more like a crocodile balancing on a tight-rope.
"When combined with the lack of any tail-drag marks, it became clear that these creatures were moving bipedally.
"They were moving in the same way as many dinosaurs, but the footprints were not made by dinosaurs.
"Dinosaurs and their bird descendants walk on their toes.
"Crocodiles walk on the flat of their feet leaving clear heel impressions, like humans do."
The footprints dated between 110-120 million years ago and were discovered after analysing animal track sites in what is now known as South Korea.
Researchers initially questioned the absence of hand impressions from the trackways, given that today's typical crocodiles are 'four-legged' or quadrupedal.
"Fossil crocodile tracks are quite rare in Asia, so finding an abundance of nearly one hundred footprints was extraordinary," Dr Romilio said.
"As an animal walks, the hind feet have the potential of stepping into the impression made by the hand and 'over-printing' it, but we find no evidence of this at these Korean sites.
Read more at Science Daily
University of Queensland palaeontologist Dr Anthony Romilio said the researchers first thought the similar-shaped fossilised footprints were from another ancient animal known as the pterosaurs.
"At one site, the footprints were initially thought to be made by a giant bipedal pterosaur walking on the mudflat, we now understand that these were bipedal crocodile prints," Dr Romilio said.
"The footprints measure around 24 centimetres, suggesting the track-makers had legs about the same height as human adult legs.
"These were long animals that we estimate were over three metres in length.
"And while footprints were everywhere on the site, there were no handprints."
The research team, led by Professor Kyung Soo Kim from Chinju National University of Education, soon found clues as to why there were no handprints.
"Typical crocodiles walk in a squat stance and create trackways that are wide," Professor Kim said.
"Oddly, our trackways are very narrow looking -- more like a crocodile balancing on a tight-rope.
"When combined with the lack of any tail-drag marks, it became clear that these creatures were moving bipedally.
"They were moving in the same way as many dinosaurs, but the footprints were not made by dinosaurs.
"Dinosaurs and their bird descendants walk on their toes.
"Crocodiles walk on the flat of their feet leaving clear heel impressions, like humans do."
The footprints dated between 110-120 million years ago and were discovered after analysing animal track sites in what is now known as South Korea.
Researchers initially questioned the absence of hand impressions from the trackways, given that today's typical crocodiles are 'four-legged' or quadrupedal.
"Fossil crocodile tracks are quite rare in Asia, so finding an abundance of nearly one hundred footprints was extraordinary," Dr Romilio said.
"As an animal walks, the hind feet have the potential of stepping into the impression made by the hand and 'over-printing' it, but we find no evidence of this at these Korean sites.
Read more at Science Daily
Volunteerism: Doing good does you good
A new study in the American Journal of Preventive Medicine, published by Elsevier, takes a closer look at the benefits of volunteering to the health and well-being of volunteers, both validating and refuting findings from previous research. The results verify that adults over 50 who volunteer for at least 100 hours a year (about two hours per week) have a substantially reduced risk of mortality and developing physical limitations, higher levels of subsequent physical activity, and improved sense of well-being later on compared to individuals who do not volunteer.
"Humans are social creatures by nature. Perhaps this is why our minds and bodies are rewarded when we give to others. Our results show that volunteerism among older adults doesn't just strengthen communities, but enriches our own lives by strengthening our bonds to others, helping us feel a sense of purpose and well-being, and protecting us from feelings of loneliness, depression, and hopelessness. Regular altruistic activity reduces our risk of death even though our study didn't show any direct impact on a wide array of chronic conditions," explained lead investigator Eric S. Kim, PhD, Department of Social and Behavioral Sciences and Lee Kum Sheung Center for Health and Happiness, Harvard T.H. Chan School of Public Health, Boston; and Human Flourishing Program, Institute for Quantitative Social Science, Harvard University, Cambridge, MA, USA.
A growing body of research has linked volunteering to many health and well-being benefits, but there is still insufficient evidence to demonstrate the consistent and specific positive outcomes that are needed to develop public health interventions based on volunteerism. This large-scale study helps address this gap by evaluating 34 physical health and psychological/social well-being outcomes. This permitted direct comparisons of the potential size of effect that volunteering might have on various outcomes and also learn which outcomes volunteering does not appear to be influencing.
The study did not confirm links between volunteering and improvements to chronic conditions such as diabetes, hypertension, stroke, cancer, heart disease, lung disease, arthritis, obesity, cognitive impairment, or chronic pain.
The analysis was based on data, face-to-face interviews, and survey responses from nearly 13,000 participants randomly selected from the Health and Retirement Study (HRS), a nationally representative sample of older adults in the United States. The participants were tracked over four years in two cohorts from 2010-2016.
The growing older adult population possesses a vast array of skills and experiences that can be leveraged for the greater good of society via volunteering. While proposing further research to better understand this phenonmena, the study recommends the adoption of policies that encourage more volunteerism. Such interventions could simultaneously enhance society and foster a trajectory of healthy aging in the rapidly growing population of older adults. Further study is also needed to learn the underlying reasons for the divergence in some of the results from previous research.
Read more at Science Daily
"Humans are social creatures by nature. Perhaps this is why our minds and bodies are rewarded when we give to others. Our results show that volunteerism among older adults doesn't just strengthen communities, but enriches our own lives by strengthening our bonds to others, helping us feel a sense of purpose and well-being, and protecting us from feelings of loneliness, depression, and hopelessness. Regular altruistic activity reduces our risk of death even though our study didn't show any direct impact on a wide array of chronic conditions," explained lead investigator Eric S. Kim, PhD, Department of Social and Behavioral Sciences and Lee Kum Sheung Center for Health and Happiness, Harvard T.H. Chan School of Public Health, Boston; and Human Flourishing Program, Institute for Quantitative Social Science, Harvard University, Cambridge, MA, USA.
A growing body of research has linked volunteering to many health and well-being benefits, but there is still insufficient evidence to demonstrate the consistent and specific positive outcomes that are needed to develop public health interventions based on volunteerism. This large-scale study helps address this gap by evaluating 34 physical health and psychological/social well-being outcomes. This permitted direct comparisons of the potential size of effect that volunteering might have on various outcomes and also learn which outcomes volunteering does not appear to be influencing.
The study did not confirm links between volunteering and improvements to chronic conditions such as diabetes, hypertension, stroke, cancer, heart disease, lung disease, arthritis, obesity, cognitive impairment, or chronic pain.
The analysis was based on data, face-to-face interviews, and survey responses from nearly 13,000 participants randomly selected from the Health and Retirement Study (HRS), a nationally representative sample of older adults in the United States. The participants were tracked over four years in two cohorts from 2010-2016.
The growing older adult population possesses a vast array of skills and experiences that can be leveraged for the greater good of society via volunteering. While proposing further research to better understand this phenonmena, the study recommends the adoption of policies that encourage more volunteerism. Such interventions could simultaneously enhance society and foster a trajectory of healthy aging in the rapidly growing population of older adults. Further study is also needed to learn the underlying reasons for the divergence in some of the results from previous research.
Read more at Science Daily
Jun 11, 2020
New distance measurements bolster challenge to basic model of universe
A new set of precision distance measurements made with an international collection of radio telescopes have greatly increased the likelihood that theorists need to revise the "standard model" that describes the fundamental nature of the Universe.
The new distance measurements allowed astronomers to refine their calculation of the Hubble Constant, the expansion rate of the Universe, a value important for testing the theoretical model describing the composition and evolution of the Universe. The problem is that the new measurements exacerbate a discrepancy between previously measured values of the Hubble Constant and the value predicted by the model when applied to measurements of the cosmic microwave background made by the Planck satellite.
"We find that galaxies are nearer than predicted by the standard model of cosmology, corroborating a problem identified in other types of distance measurements. There has been debate over whether this problem lies in the model itself or in the measurements used to test it. Our work uses a distance measurement technique completely independent of all others, and we reinforce the disparity between measured and predicted values. It is likely that the basic cosmological model involved in the predictions is the problem," said James Braatz, of the National Radio Astronomy Observatory (NRAO).
Braatz leads the Megamaser Cosmology Project, an international effort to measure the Hubble Constant by finding galaxies with specific properties that lend themselves to yielding precise geometric distances. The project has used the National Science Foundation's Very Long Baseline Array (VLBA), Karl G. Jansky Very Large Array (VLA), and Robert C. Byrd Green Bank Telescope (GBT), along with the Effelsberg telescope in Germany. The team reported their latest results in the Astrophysical Journal Letters.
Edwin Hubble, after whom the orbiting Hubble Space Telescope is named, first calculated the expansion rate of the universe (the Hubble Constant) in 1929 by measuring the distances to galaxies and their recession speeds. The more distant a galaxy is, the greater its recession speed from Earth. Today, the Hubble Constant remains a fundamental property of observational cosmology and a focus of many modern studies.
Measuring recession speeds of galaxies is relatively straightforward. Determining cosmic distances, however, has been a difficult task for astronomers. For objects in our own Milky Way Galaxy, astronomers can get distances by measuring the apparent shift in the object's position when viewed from opposite sides of Earth's orbit around the Sun, an effect called parallax. The first such measurement of a star's parallax distance came in 1838.
Beyond our own Galaxy, parallaxes are too small to measure, so astronomers have relied on objects called "standard candles," so named because their intrinsic brightness is presumed to be known. The distance to an object of known brightness can be calculated based on how dim the object appears from Earth. These standard candles include a class of stars called Cepheid variables and a specific type of stellar explosion called a Type Ia supernova.
Another method of estimating the expansion rate involves observing distant quasars whose light is bent by the gravitational effect of a foreground galaxy into multiple images. When the quasar varies in brightness, the change appears in the different images at different times. Measuring this time difference, along with calculations of the geometry of the light-bending, yields an estimate of the expansion rate.
Determinations of the Hubble Constant based on the standard candles and the gravitationally-lensed quasars have produced figures of 73-74 kilometers per second (the speed) per megaparsec (distance in units favored by astronomers).
However, predictions of the Hubble Constant from the standard cosmological model when applied to measurements of the cosmic microwave background (CMB) -- the leftover radiation from the Big Bang -- produce a value of 67.4, a significant and troubling difference. This difference, which astronomers say is beyond the experimental errors in the observations, has serious implications for the standard model.
The model is called Lambda Cold Dark Matter, or Lambda CDM, where "Lambda" refers to Einstein's cosmological constant and is a representation of dark energy. The model divides the composition of the Universe mainly between ordinary matter, dark matter, and dark energy, and describes how the Universe has evolved since the Big Bang.
The Megamaser Cosmology Project focuses on galaxies with disks of water-bearing molecular gas orbiting supermassive black holes at the galaxies' centers. If the orbiting disk is seen nearly edge-on from Earth, bright spots of radio emission, called masers -- radio analogs to visible-light lasers -- can be used to determine both the physical size of the disk and its angular extent, and therefore, through geometry, its distance. The project's team uses the worldwide collection of radio telescopes to make the precision measurements required for this technique.
In their latest work, the team refined their distance measurements to four galaxies, at distances ranging from 168 million light-years to 431 million light-years. Combined with previous distance measurements of two other galaxies, their calculations produced a value for the Hubble Constant of 73.9 kilometers per second per megaparsec.
"Testing the standard model of cosmology is a really challenging problem that requires the best-ever measurements of the Hubble Constant. The discrepancy between the predicted and measured values of the Hubble Constant points to one of the most fundamental problems in all of physics, so we would like to have multiple, independent measurements that corroborate the problem and test the model. Our method is geometric, and completely independent of all others, and it reinforces the discrepancy," said Dom Pesce, a researcher at the Center for Astrophysics | Harvard and Smithsonian, and lead author on the latest paper.
"The maser method of measuring the expansion rate of the universe is elegant, and, unlike the others, based on geometry. By measuring extremely precise positions and dynamics of maser spots in the accretion disk surrounding a distant black hole, we can determine the distance to the host galaxies and then the expansion rate. Our result from this unique technique strengthens the case for a key problem in observational cosmology." said Mark Reid of the Center for Astrophysics | Harvard and Smithsonian, and a member of the Megamaser Cosmology Project team.
"Our measurement of the Hubble Constant is very close to other recent measurements, and statistically very different from the predictions based on the CMB and the standard cosmological model. All indications are that the standard model needs revision," said Braatz.
Astronomers have various ways to adjust the model to resolve the discrepancy. Some of these include changing presumptions about the nature of dark energy, moving away from Einstein's cosmological constant. Others look at fundamental changes in particle physics, such as changing the numbers or types of neutrinos or the possibilities of interactions among them. There are other possibilities, even more exotic, and at the moment scientists have no clear evidence for discriminating among them.
"This is a classic case of the interplay between observation and theory. The Lambda CDM model has worked quite well for years, but now observations clearly are pointing to a problem that needs to be solved, and it appears the problem lies with the model," Pesce said.
Read more at Science Daily
The new distance measurements allowed astronomers to refine their calculation of the Hubble Constant, the expansion rate of the Universe, a value important for testing the theoretical model describing the composition and evolution of the Universe. The problem is that the new measurements exacerbate a discrepancy between previously measured values of the Hubble Constant and the value predicted by the model when applied to measurements of the cosmic microwave background made by the Planck satellite.
"We find that galaxies are nearer than predicted by the standard model of cosmology, corroborating a problem identified in other types of distance measurements. There has been debate over whether this problem lies in the model itself or in the measurements used to test it. Our work uses a distance measurement technique completely independent of all others, and we reinforce the disparity between measured and predicted values. It is likely that the basic cosmological model involved in the predictions is the problem," said James Braatz, of the National Radio Astronomy Observatory (NRAO).
Braatz leads the Megamaser Cosmology Project, an international effort to measure the Hubble Constant by finding galaxies with specific properties that lend themselves to yielding precise geometric distances. The project has used the National Science Foundation's Very Long Baseline Array (VLBA), Karl G. Jansky Very Large Array (VLA), and Robert C. Byrd Green Bank Telescope (GBT), along with the Effelsberg telescope in Germany. The team reported their latest results in the Astrophysical Journal Letters.
Edwin Hubble, after whom the orbiting Hubble Space Telescope is named, first calculated the expansion rate of the universe (the Hubble Constant) in 1929 by measuring the distances to galaxies and their recession speeds. The more distant a galaxy is, the greater its recession speed from Earth. Today, the Hubble Constant remains a fundamental property of observational cosmology and a focus of many modern studies.
Measuring recession speeds of galaxies is relatively straightforward. Determining cosmic distances, however, has been a difficult task for astronomers. For objects in our own Milky Way Galaxy, astronomers can get distances by measuring the apparent shift in the object's position when viewed from opposite sides of Earth's orbit around the Sun, an effect called parallax. The first such measurement of a star's parallax distance came in 1838.
Beyond our own Galaxy, parallaxes are too small to measure, so astronomers have relied on objects called "standard candles," so named because their intrinsic brightness is presumed to be known. The distance to an object of known brightness can be calculated based on how dim the object appears from Earth. These standard candles include a class of stars called Cepheid variables and a specific type of stellar explosion called a Type Ia supernova.
Another method of estimating the expansion rate involves observing distant quasars whose light is bent by the gravitational effect of a foreground galaxy into multiple images. When the quasar varies in brightness, the change appears in the different images at different times. Measuring this time difference, along with calculations of the geometry of the light-bending, yields an estimate of the expansion rate.
Determinations of the Hubble Constant based on the standard candles and the gravitationally-lensed quasars have produced figures of 73-74 kilometers per second (the speed) per megaparsec (distance in units favored by astronomers).
However, predictions of the Hubble Constant from the standard cosmological model when applied to measurements of the cosmic microwave background (CMB) -- the leftover radiation from the Big Bang -- produce a value of 67.4, a significant and troubling difference. This difference, which astronomers say is beyond the experimental errors in the observations, has serious implications for the standard model.
The model is called Lambda Cold Dark Matter, or Lambda CDM, where "Lambda" refers to Einstein's cosmological constant and is a representation of dark energy. The model divides the composition of the Universe mainly between ordinary matter, dark matter, and dark energy, and describes how the Universe has evolved since the Big Bang.
The Megamaser Cosmology Project focuses on galaxies with disks of water-bearing molecular gas orbiting supermassive black holes at the galaxies' centers. If the orbiting disk is seen nearly edge-on from Earth, bright spots of radio emission, called masers -- radio analogs to visible-light lasers -- can be used to determine both the physical size of the disk and its angular extent, and therefore, through geometry, its distance. The project's team uses the worldwide collection of radio telescopes to make the precision measurements required for this technique.
In their latest work, the team refined their distance measurements to four galaxies, at distances ranging from 168 million light-years to 431 million light-years. Combined with previous distance measurements of two other galaxies, their calculations produced a value for the Hubble Constant of 73.9 kilometers per second per megaparsec.
"Testing the standard model of cosmology is a really challenging problem that requires the best-ever measurements of the Hubble Constant. The discrepancy between the predicted and measured values of the Hubble Constant points to one of the most fundamental problems in all of physics, so we would like to have multiple, independent measurements that corroborate the problem and test the model. Our method is geometric, and completely independent of all others, and it reinforces the discrepancy," said Dom Pesce, a researcher at the Center for Astrophysics | Harvard and Smithsonian, and lead author on the latest paper.
"The maser method of measuring the expansion rate of the universe is elegant, and, unlike the others, based on geometry. By measuring extremely precise positions and dynamics of maser spots in the accretion disk surrounding a distant black hole, we can determine the distance to the host galaxies and then the expansion rate. Our result from this unique technique strengthens the case for a key problem in observational cosmology." said Mark Reid of the Center for Astrophysics | Harvard and Smithsonian, and a member of the Megamaser Cosmology Project team.
"Our measurement of the Hubble Constant is very close to other recent measurements, and statistically very different from the predictions based on the CMB and the standard cosmological model. All indications are that the standard model needs revision," said Braatz.
Astronomers have various ways to adjust the model to resolve the discrepancy. Some of these include changing presumptions about the nature of dark energy, moving away from Einstein's cosmological constant. Others look at fundamental changes in particle physics, such as changing the numbers or types of neutrinos or the possibilities of interactions among them. There are other possibilities, even more exotic, and at the moment scientists have no clear evidence for discriminating among them.
"This is a classic case of the interplay between observation and theory. The Lambda CDM model has worked quite well for years, but now observations clearly are pointing to a problem that needs to be solved, and it appears the problem lies with the model," Pesce said.
Read more at Science Daily
After a century of searching, scientists find new liquid phase
Researchers at the University of Colorado Boulder's Soft Materials Research Center (SMRC) have discovered an elusive phase of matter, first proposed more than 100 years ago and sought after ever since.
The team describes the discovery of what scientists call a "ferroelectric nematic" phase of liquid crystal in a study published today in the Proceedings of the National Academy of Sciences. The discovery opens a door to a new universe of materials, said co-author Matt Glaser, a professor in the Department of Physics.
Nematic liquid crystals have been a hot topic in materials research since the 1970s. These materials exhibit a curious mix of fluid- and solid-like behaviors, which allow them to control light. Engineers have used them extensively to make the liquid crystal displays (LCDs) in many laptops, TVs and cellphones.
Think of nematic liquid crystals like dropping a handful of pins on a table. The pins in this case are rod-shaped molecules that are "polar" -- with heads (the blunt ends) that carry a positive charge and tails (the pointy ends) that are negatively charged. In a traditional nematic liquid crystal, half of the pins point left and the other half point right, with the direction chosen at random.
A ferroelectric nematic liquid crystal phase, however, is much more disciplined. In such a liquid crystal, patches or "domains" form in the sample in which the molecules all point in the same direction, either right or left. In physics parlance, these materials have polar ordering.
Noel Clark, a professor of physics and director of the SMRC, said that his team's discovery of one such liquid crystal could open up a wealth of technological innovations -- from new types of display screens to reimagined computer memory.
"There are 40,000 research papers on nematics, and in almost any one of them you see interesting new possibilities if the nematic had been ferroelectric," Clark said.
Under the microscope
The discovery is years in the making.
Nobel Laureates Peter Debye and Max Born first suggested in the 1910s that, if you designed a liquid crystal correctly, its molecules could spontaneously fall into a polar ordered state. Not long after that, researchers began to discover solid crystals that did something similar: Their molecules pointed in uniform directions. They could also be reversed, flipping from right to left or vice versa under an applied electric field. These solid crystals were called "ferroelectrics" because of their similarities to magnets. (Ferrum is Latin for "iron").
In the decades since, however, scientists struggled to find a liquid crystal phase that behaved in the same way. That is, until Clark and his colleagues began examining RM734, an organic molecule created by a group of British scientists several years ago.
That same British group, plus a second team of Slovenian scientists, reported that RM734 exhibited a conventional nematic liquid crystal phase at higher temperatures. At lower temperatures, another unusual phase appeared.
When Clark's team tried to observe that strange phase under the microscope they noticed something new. Under a weak electric field, a palette of striking colors developed toward the edges of the cell containing the liquid crystal.
"It was like connecting a light bulb to voltage to test it but finding the socket and hookup wires glowing much more brightly instead," Clark said.
Stunning results
So, what was happening?
The researchers ran more tests and discovered that this phase of RM734 was 100 to 1,000 times more responsive to electric fields than the usual nematic liquid crystals. This suggested that the molecules that make up the liquid crystal demonstrated strong polar order.
"When the molecules are all pointing to the left, and they all see a field that says, 'go right,' the response is dramatic," Clark said.
The team also discovered that distinct domains seemed to form spontaneously in the liquid crystal when it cooled from higher temperature. There were, in other words, patches within their sample in which the molecules seemed to be aligned.
"That confirmed that this phase was, indeed, a ferroelectric nematic fluid," Clark said.
That alignment was also more uniform than the team was expecting.
"Entropy reigns in a fluid," said Joe MacLennan, a study coauthor and a professor of physics at CU Boulder. "Everything is wiggling around, so we expected a lot of disorder."
When the researchers examined how well aligned the molecules were inside a single domain, "we were stunned by the result," MacLennan said. The molecules were nearly all pointing in the same direction.
The team's next goal is to discover how RM734 achieves this rare feat. Glaser and SMRC researcher Dmitry Bedrov of the University of Utah, are currently using computer simulation to tackle this question.
"This work suggests that there are other ferroelectric fluids hiding in plain sight," Clark said. "It is exciting that right now techniques like artificial intelligence are emerging that will enable an efficient search for them."
Read more at Science Daily
The team describes the discovery of what scientists call a "ferroelectric nematic" phase of liquid crystal in a study published today in the Proceedings of the National Academy of Sciences. The discovery opens a door to a new universe of materials, said co-author Matt Glaser, a professor in the Department of Physics.
Nematic liquid crystals have been a hot topic in materials research since the 1970s. These materials exhibit a curious mix of fluid- and solid-like behaviors, which allow them to control light. Engineers have used them extensively to make the liquid crystal displays (LCDs) in many laptops, TVs and cellphones.
Think of nematic liquid crystals like dropping a handful of pins on a table. The pins in this case are rod-shaped molecules that are "polar" -- with heads (the blunt ends) that carry a positive charge and tails (the pointy ends) that are negatively charged. In a traditional nematic liquid crystal, half of the pins point left and the other half point right, with the direction chosen at random.
A ferroelectric nematic liquid crystal phase, however, is much more disciplined. In such a liquid crystal, patches or "domains" form in the sample in which the molecules all point in the same direction, either right or left. In physics parlance, these materials have polar ordering.
Noel Clark, a professor of physics and director of the SMRC, said that his team's discovery of one such liquid crystal could open up a wealth of technological innovations -- from new types of display screens to reimagined computer memory.
"There are 40,000 research papers on nematics, and in almost any one of them you see interesting new possibilities if the nematic had been ferroelectric," Clark said.
Under the microscope
The discovery is years in the making.
Nobel Laureates Peter Debye and Max Born first suggested in the 1910s that, if you designed a liquid crystal correctly, its molecules could spontaneously fall into a polar ordered state. Not long after that, researchers began to discover solid crystals that did something similar: Their molecules pointed in uniform directions. They could also be reversed, flipping from right to left or vice versa under an applied electric field. These solid crystals were called "ferroelectrics" because of their similarities to magnets. (Ferrum is Latin for "iron").
In the decades since, however, scientists struggled to find a liquid crystal phase that behaved in the same way. That is, until Clark and his colleagues began examining RM734, an organic molecule created by a group of British scientists several years ago.
That same British group, plus a second team of Slovenian scientists, reported that RM734 exhibited a conventional nematic liquid crystal phase at higher temperatures. At lower temperatures, another unusual phase appeared.
When Clark's team tried to observe that strange phase under the microscope they noticed something new. Under a weak electric field, a palette of striking colors developed toward the edges of the cell containing the liquid crystal.
"It was like connecting a light bulb to voltage to test it but finding the socket and hookup wires glowing much more brightly instead," Clark said.
Stunning results
So, what was happening?
The researchers ran more tests and discovered that this phase of RM734 was 100 to 1,000 times more responsive to electric fields than the usual nematic liquid crystals. This suggested that the molecules that make up the liquid crystal demonstrated strong polar order.
"When the molecules are all pointing to the left, and they all see a field that says, 'go right,' the response is dramatic," Clark said.
The team also discovered that distinct domains seemed to form spontaneously in the liquid crystal when it cooled from higher temperature. There were, in other words, patches within their sample in which the molecules seemed to be aligned.
"That confirmed that this phase was, indeed, a ferroelectric nematic fluid," Clark said.
That alignment was also more uniform than the team was expecting.
"Entropy reigns in a fluid," said Joe MacLennan, a study coauthor and a professor of physics at CU Boulder. "Everything is wiggling around, so we expected a lot of disorder."
When the researchers examined how well aligned the molecules were inside a single domain, "we were stunned by the result," MacLennan said. The molecules were nearly all pointing in the same direction.
The team's next goal is to discover how RM734 achieves this rare feat. Glaser and SMRC researcher Dmitry Bedrov of the University of Utah, are currently using computer simulation to tackle this question.
"This work suggests that there are other ferroelectric fluids hiding in plain sight," Clark said. "It is exciting that right now techniques like artificial intelligence are emerging that will enable an efficient search for them."
Read more at Science Daily
Tropical disease in medieval Europe revises the history of a pathogen related to syphilis
Mass burials are common remnants of the many plague outbreaks that ravaged Medieval Europe. A number of these graveyards are well documented in historical sources, but the locations of most, and the victims they contain, have been lost to the pages of time. In Vilnius, Lithuania, one such cemetery was found in a typical way: accidental discovery during a routine city construction project.
A new study published in the journal Scientific Reports details the findings of genomic analyses on these medieval skeletons, with important implications for the history of syphilis in Europe.
Just another plague pit?
"Historical information on this Vilnius graveyard is unavailable, but the burial context, along with its location outside of the medieval city limits, pointed to plague, or some other major infectious disease outbreak," comments Rimantas Jankauskas, Professor of the Faculty of Medicine, Vilnius University. "To be certain, we needed confirmation through DNA analysis."
Kirsten Bos, a group leader for Molecular Palaeopathology at the Max Planck Institute for the Science of Human History (MPI-SHH) in Jena, Germany, is frequently contacted by archaeologists requesting such analyses.
"Plague was a common disease at the time, and the information we get from all the ancient DNA work can tell us a lot about how it was spreading," says Bos, a specialist in ancient pathogen DNA recovery who led the current study.
Working in Bos's team, doctoral candidate Karen Giffin took on DNA analysis of the putative plague victims and quickly identified the pathogen's DNA in the teeth of several individuals.
"I was happy to have identified them as victims of medieval plague," says Giffin, "but we wanted to see if the new techniques we were developing in molecular detection of pathogens could allow us to learn anything more about the health of this population."
More than just plague
"The typical method for pathogen detection in archaeological bone requires that you have some idea of what you're looking for," explains Alexander Herbig, group leader of Computational Pathogenomics at the MPI-SHH. "In this case we applied a relatively new hypothesis-free DNA screening approach to search for any other pathogens we might be able to identify at the molecular level."
This process unlocked a second secret of the 15th century graveyard. One of the four plague victims, a young woman, also showed a weak signal of something that seemed related to modern syphilis.
"It was impressive to find traces of such a disease in an historical skeleton because their molecular preservation in ancient bone is known to be problematic," comments Bos.
Diseases in the syphilis family, known as the treponemal diseases, are assumed to have had a long history with humans, though their inferred history in Europe is laden with controversy. The prevailing opinion holds that the first outbreak of syphilis in Europe coincided with Charles VIII's 1495 siege of Naples, where a debilitating disease erupted amongst his infantry and quickly spread around Europe. Since this outbreak happened just after the return of Columbus and his crew from their first trans-Atlantic voyage, most discussants believe syphilis was a newcomer to Europe that originated in the New World. But support is growing for a different theory. An increasing number of specialists in bone pathology believe they have properly identified examples of pre-1493 syphilis in Europe, which has ignited on-going debates about models of its evolution.
"We were able to reconstruct an impressively well-preserved genome that, to our surprise, fell within the diversity of modern yaws," comments Giffin. Yaws is a lesser-known treponemal disease primarily of the skin that affects both humans and other primates in warm, tropical environments. "Finding it in northern Europe in the mid-15th century was unexpected," she adds.
Yaws seems much younger than we thought
Since yaws infects both humans and non-human primates, some believe it to be a very old disease, having been with humans before the massive Pleistocene migrations that spread us around the globe.
"To our surprise, the yaws genome we reconstructed was just a few genetic steps away from the ancestor of all yaws varieties known in humans and non-human primates," says Bos. "Given the age of our medieval skeletons, it seems that all strains of yaws that we know today appeared on the scene only about 1000 years ago."
"This has important implications for the history of treponemal disease in Europe," Bos adds. "We can now confirm that yaws was circulating in medieval Europe, and given its similarity to syphilis and its recent emergence, it's possible that yaws contributed in some way to the famous late 15th to 16th century outbreak that we normally ascribe only to syphilis."
One possibility is that yaws emerged in either humans or other primates in West Africa within the last millennium and made its way to Europe in the mid-15th century. European presence in West Africa increased in the 15th century, as did the forced relocations of Africans to Europe through establishment of the transatlantic slave trade. These activities would have rapidly disseminated a new and highly contagious disease such as yaws.
Read more at Science Daily
A new study published in the journal Scientific Reports details the findings of genomic analyses on these medieval skeletons, with important implications for the history of syphilis in Europe.
Just another plague pit?
"Historical information on this Vilnius graveyard is unavailable, but the burial context, along with its location outside of the medieval city limits, pointed to plague, or some other major infectious disease outbreak," comments Rimantas Jankauskas, Professor of the Faculty of Medicine, Vilnius University. "To be certain, we needed confirmation through DNA analysis."
Kirsten Bos, a group leader for Molecular Palaeopathology at the Max Planck Institute for the Science of Human History (MPI-SHH) in Jena, Germany, is frequently contacted by archaeologists requesting such analyses.
"Plague was a common disease at the time, and the information we get from all the ancient DNA work can tell us a lot about how it was spreading," says Bos, a specialist in ancient pathogen DNA recovery who led the current study.
Working in Bos's team, doctoral candidate Karen Giffin took on DNA analysis of the putative plague victims and quickly identified the pathogen's DNA in the teeth of several individuals.
"I was happy to have identified them as victims of medieval plague," says Giffin, "but we wanted to see if the new techniques we were developing in molecular detection of pathogens could allow us to learn anything more about the health of this population."
More than just plague
"The typical method for pathogen detection in archaeological bone requires that you have some idea of what you're looking for," explains Alexander Herbig, group leader of Computational Pathogenomics at the MPI-SHH. "In this case we applied a relatively new hypothesis-free DNA screening approach to search for any other pathogens we might be able to identify at the molecular level."
This process unlocked a second secret of the 15th century graveyard. One of the four plague victims, a young woman, also showed a weak signal of something that seemed related to modern syphilis.
"It was impressive to find traces of such a disease in an historical skeleton because their molecular preservation in ancient bone is known to be problematic," comments Bos.
Diseases in the syphilis family, known as the treponemal diseases, are assumed to have had a long history with humans, though their inferred history in Europe is laden with controversy. The prevailing opinion holds that the first outbreak of syphilis in Europe coincided with Charles VIII's 1495 siege of Naples, where a debilitating disease erupted amongst his infantry and quickly spread around Europe. Since this outbreak happened just after the return of Columbus and his crew from their first trans-Atlantic voyage, most discussants believe syphilis was a newcomer to Europe that originated in the New World. But support is growing for a different theory. An increasing number of specialists in bone pathology believe they have properly identified examples of pre-1493 syphilis in Europe, which has ignited on-going debates about models of its evolution.
"We were able to reconstruct an impressively well-preserved genome that, to our surprise, fell within the diversity of modern yaws," comments Giffin. Yaws is a lesser-known treponemal disease primarily of the skin that affects both humans and other primates in warm, tropical environments. "Finding it in northern Europe in the mid-15th century was unexpected," she adds.
Yaws seems much younger than we thought
Since yaws infects both humans and non-human primates, some believe it to be a very old disease, having been with humans before the massive Pleistocene migrations that spread us around the globe.
"To our surprise, the yaws genome we reconstructed was just a few genetic steps away from the ancestor of all yaws varieties known in humans and non-human primates," says Bos. "Given the age of our medieval skeletons, it seems that all strains of yaws that we know today appeared on the scene only about 1000 years ago."
"This has important implications for the history of treponemal disease in Europe," Bos adds. "We can now confirm that yaws was circulating in medieval Europe, and given its similarity to syphilis and its recent emergence, it's possible that yaws contributed in some way to the famous late 15th to 16th century outbreak that we normally ascribe only to syphilis."
One possibility is that yaws emerged in either humans or other primates in West Africa within the last millennium and made its way to Europe in the mid-15th century. European presence in West Africa increased in the 15th century, as did the forced relocations of Africans to Europe through establishment of the transatlantic slave trade. These activities would have rapidly disseminated a new and highly contagious disease such as yaws.
Read more at Science Daily
Newly synthesized fungal compound can switch on a self-destruct button for cancer
All human body cells have a certain lifespan, during which they perform their essential duties. At the end of this lifespan, they reach senescence and-no longer able to perform those duties-die. This suicidal death is programmed into their genes through a process called apoptosis, causing them to self-destruct in order to make way for fresh, young, and healthy cells to replace them.
Mutations in a special gene called p53 can sometimes interfere with this process. Caused by aging, ultraviolet light, and various mutagenic compounds, these mutations can disable the apoptosis gene, resulting in "zombie" cells that refuse to die and continue to multiply, spreading the disabled gene and replacing healthy working cells with undying, rapidly growing tumors. This is the disease that we call cancer, and it takes many forms depending on which body cells develop the mutations.
Previously, scientists identified an anticancer compound called FE399 in a species of filamentous fungus called Ascochyta, which is often found afflicting common food crops such as cereals. The compound is a specific group of depsipeptides, a type of amino acid group, and was shown to induce apoptosis in cancerous human cells, particularly colorectal cancer, while they are still in vitro, proving its worth as an anti-cancer chemical.
Unfortunately, due to a variety of chemical complexities, the FE399 compound is not easy to purify, which hindered any plans for its widespread applications in cancer treatment. It was thus clear that extracting FE399?from the fungi naturally would not be a commercially feasible method, and despite the promise of a powerful anticancer drug, research into this particular compound was stalled.
The promise of a new anticancer treatment was tempting, however, and Prof Isamu Shiina, along with Dr Takayuki Tonoi, and his team from the Tokyo University of Science, accepted the challenge. "We wanted to create a lead compound that could treat colon cancer, and we aimed to do this through the total synthesis of FE399," says Prof Shiina. Total synthesis is the process of the complete chemical synthesis (production) of a complex molecule using commercially available precursors, allowing mass production. The results of their extensive studies will be published in the European Journal of Organic Chemistry.
The team figured that first, the structure of the depsipeptide would need to be identified. This was simple and could be easily performed using commercially available and inexpensive materials. Following this simple start, the subsequent procedures required many steps and resulted in some small failures when isomers were unsuccessfully isolated.
However, the team was rewarded for their efforts when, in a major breakthrough, their mass spectrometry and nuclear magnetic resonance studies confirmed that a trio of spots on a plate showed identical chemical signature to the known formula of FE399, meaning that they were able to successfully recreate FE399 synthetically.
Their technique was found to have an overall yield of 20%, which is quite promising for future large-scale production plans. "We hope that this newly produced compound can provide an unprecedented treatment option for patients with colorectal cancer, and thus improve the overall outcomes of the disease and ultimately improve their quality of life," states Prof Shiina.
Read more at Science Daily
Mutations in a special gene called p53 can sometimes interfere with this process. Caused by aging, ultraviolet light, and various mutagenic compounds, these mutations can disable the apoptosis gene, resulting in "zombie" cells that refuse to die and continue to multiply, spreading the disabled gene and replacing healthy working cells with undying, rapidly growing tumors. This is the disease that we call cancer, and it takes many forms depending on which body cells develop the mutations.
Previously, scientists identified an anticancer compound called FE399 in a species of filamentous fungus called Ascochyta, which is often found afflicting common food crops such as cereals. The compound is a specific group of depsipeptides, a type of amino acid group, and was shown to induce apoptosis in cancerous human cells, particularly colorectal cancer, while they are still in vitro, proving its worth as an anti-cancer chemical.
Unfortunately, due to a variety of chemical complexities, the FE399 compound is not easy to purify, which hindered any plans for its widespread applications in cancer treatment. It was thus clear that extracting FE399?from the fungi naturally would not be a commercially feasible method, and despite the promise of a powerful anticancer drug, research into this particular compound was stalled.
The promise of a new anticancer treatment was tempting, however, and Prof Isamu Shiina, along with Dr Takayuki Tonoi, and his team from the Tokyo University of Science, accepted the challenge. "We wanted to create a lead compound that could treat colon cancer, and we aimed to do this through the total synthesis of FE399," says Prof Shiina. Total synthesis is the process of the complete chemical synthesis (production) of a complex molecule using commercially available precursors, allowing mass production. The results of their extensive studies will be published in the European Journal of Organic Chemistry.
The team figured that first, the structure of the depsipeptide would need to be identified. This was simple and could be easily performed using commercially available and inexpensive materials. Following this simple start, the subsequent procedures required many steps and resulted in some small failures when isomers were unsuccessfully isolated.
However, the team was rewarded for their efforts when, in a major breakthrough, their mass spectrometry and nuclear magnetic resonance studies confirmed that a trio of spots on a plate showed identical chemical signature to the known formula of FE399, meaning that they were able to successfully recreate FE399 synthetically.
Their technique was found to have an overall yield of 20%, which is quite promising for future large-scale production plans. "We hope that this newly produced compound can provide an unprecedented treatment option for patients with colorectal cancer, and thus improve the overall outcomes of the disease and ultimately improve their quality of life," states Prof Shiina.
Read more at Science Daily
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