Earth

SEATTLE - At what age do you feel 65?

A 30-year gap separates countries with the highest and lowest ages at which people experience the health problems of a 65-year-old, according to a new scientific study.

Researchers found 76-year-olds in Japan and 46-year-olds in Papua New Guinea have the same level of age-related health problems as an "average" person aged 65.

"These disparate findings show that increased life expectancy at older ages can either be an opportunity or a threat to the overall welfare of populations, depending on the aging-related health problems the population experiences regardless of chronological age." said Dr. Angela Y. Chang, lead author and postdoctoral fellow at the Center for Health Trends and Forecasts at the University of Washington. "Age-related health problems can lead to early retirement, a smaller workforce, and higher health spending. Government leaders and other stakeholders influencing health systems need to consider when people begin suffering the negative effects of aging."

These negative effects include impaired functions and loss of physical, mental, and cognitive abilities resulting from the 92 conditions analyzed, five of which are communicable and 81 non-communicable, along with six injuries.

The studies and additional information are available at http://www.healthdata.org

Link to The Lancet Public Health study: https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(19)30019-2/fulltext

The study, published yesterday in the international medical journal The Lancet Public Health, is the first of its kind, according to Chang, whose center is housed at the UW's Institute for Health Metrics and Evaluation. Where traditional metrics of aging examine increased longevity, this study explores both chronological age and the pace at which aging contributes to health deterioration. The study uses estimates from the Global Burden of Disease study (GBD).

Researchers measured "age-related disease burden" by aggregating all disability-adjusted life years (DALYs), a measurement of loss of healthy life, related to the 92 diseases. The findings cover 1990 to 2017 in 195 countries and territories. For example, in 2017, people in Papua New Guinea had the world's highest rate of age-related health problems with more than 500 DALYs per 1,000 adults, four times that of people in Switzerland with just over 100 DALYs per 1,000 adults.

The rate in the United States was 161.5 DALYs per 1,000, giving it a ranking of 53rd, between Algeria at 52nd with 161.0 DALYs per 1,000 and Iran at 54th with 164.8 DALYs per 1,000.

Using global average 65-year-olds as a reference group, Chang and other researchers also estimated the ages at which the population in each country experienced the same related burden rate. They found wide variation in how well or poorly people age. Ranked first, Japanese 76-year-olds experience the same aging burden as 46-year-olds in Papua New Guinea, which ranked last across 195 countries and territories. At 68.5 years, the United States ranked 54th, between Iran (69.0 years) and Antigua and Barbuda (68.4 years).

The study is entitled "Measuring population ageing: an analysis of the Global Burden of Disease Study 2017."

Additional findings include:

Age-related disease burden rates decreased over time across all regions between 1990 and 2017, representing reductions in deaths and disease severity of age-related problems.

In 2017, people in 108 countries experienced earlier accumulation of problems associated with aging, whereas those in 87 countries experienced slower onset of aging.

Globally, the age-related diseases with the most deaths and DALYs were ischemic heart disease, brain hemorrhage, and chronic obstructive pulmonary disease (COPD).

Countries with highest equivalent age to global 65-year-olds in 2017:

1. Japan: 76.1 years

2. Switzerland: 76.1

3. France: 76.0

4. Singapore: 76.0

5. Kuwait: 75.3

6. South Korea: 75.1

7. Spain: 75.1

8. Italy: 74.8

9. Puerto Rico: 74.6

10. Peru: 74.3

Countries with lowest equivalent age to global 65-year-olds in 2017:

1. Papua New Guinea: 45.6 years

2. Marshall Islands: 51.0

3. Afghanistan: 51.6

4. Vanuatu: 52.2

5. Solomon Islands: 53.4

6. Central African Republic: 53.6

7. Lesotho: 53.6

8. Kiribati: 54.2

9. Guinea-Bissau: 54.5

10. Federated States of Micronesia: 55.0

Countries with lowest age-related burden rate in 2017:

1. Switzerland: 104.9 DALYs per 1,000 adults aged 25 or older

2. Singapore: 108.3

3. South Korea: 110.1

4. Japan: 110.6

5. Italy: 115.2

6. Kuwait: 118.2

7. Spain: 119.2

8. France: 119.3

9. Israel: 120.2

10. Sweden: 122.1

Countries with highest age-related burden rate in 2017:

1. Papua New Guinea: 506.6 DALYs per 1,000 adults aged 25 or older

2. Marshall Islands: 396.6

3. Vanuatu: 392.1

4. Afghanistan: 380.2

5. Solomon Islands: 368.0

6. Central African Republic: 364.6

7. Lesotho: 360.5

8. Kiribati: 347.5

9. Guinea-Bissau: 343.4

10. Eritrea: 325.7

Fukuoka, Japan -- Humanity needs to improve when it comes to reducing carbon emissions to prevent the worst effects of climate change. If the world is to meet the IPCC's minimum target of keeping global temperature increases below 1.5 °C, every possible avenue for CO2 remediation must be explored.

Geological trapping can play a major role here. Our planet's underground rocks and sediments offer a vast potential space for long-term carbon storage. To support this, a recent computational study from a Japanese-led international group at Kyushu University shows how trapped carbon dioxide can be converted into harmless minerals.

The rocks beneath the earth's surface are highly porous, and trapping involves injecting CO2 into the pores after collecting it from its emission source. Although CO2 is usually considered too stable to react chemically with rock, it can bind tightly to the surface by physical adsorption. Eventually it dissolves in water, forming carbonic acid, which can react with aqueous metals to form carbonate minerals.

"Mineralization is the most stable method of long-term CO2 storage, locking CO2 into a completely secure form that can't be re-emitted," explains Jihui Jia of the International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, first author of the study. "This was once thought to take thousands of years, but that view is rapidly changing. The chemical reactions are not fully understood because they're so hard to reproduce in the lab. This is where modeling comes in."

As reported in The Journal of Physical Chemistry C, simulations were initially run to predict what happens when carbon dioxide collides with a cleaved quartz surface--quartz (SiO2) being abundant in the earth's crust. When the simulation trajectories were played back, the CO2 molecules were seen bending from their linear O=C=O shape to form trigonal CO3 units bonded with the quartz.

In a second round of simulations, H2O molecules were added to mimic the "formation water" that is often present beneath oil and gas drilling sites. Intriguingly, the H2O molecules spontaneously attacked the reactive CO3 structures, breaking the Si-O bonds to produce carbonate ions. Just like carbonic acid, carbonate ions can react with dissolved metal cations (such as Mg2+, Ca2+, and Fe2+) to bind carbon permanently into mineral form.

Together, the simulations show that both steps of CO2 mineralization--carbonation (binding to rock) and hydrolysis (reacting with water)--are favorable. Moreover, free carbonate ions can be made by hydrolysis, not just by dissociation of carbonic acid as was once assumed. These insights relied on a sophisticated form of molecular dynamics that models not just the physical collisions between atoms, but electron transfer, the essence of chemistry.

"Our results suggest some ways to improve geological trapping," says study lead author Takeshi Tsuji. "For quartz to capture CO2, it must be a cleaved surface, so the silicon and oxygen atoms have reactive 'dangling' bonds. In real life, however, the surface might be protected by hydrogen bonding and cations, which would prevent mineralization. We need a way to strip off those cations or dehydrogenate the surface."

Evidence is growing that captured CO2 can mineralize much faster than previously believed. While this is exciting, the Kyushu paper underlines how complex and delicate the chemistry can be. For now, the group recommends further studies on other abundant rocks, like basalt, to map out the role that geochemical trapping can play in the greatest technical challenge facing civilization.

Eighty-six percent of individuals who entered HIV care soon after diagnosis maintained viral suppression after 48 weeks during a clinical trial conducted at four National Institutes of Health (NIH)-funded Centers for AIDS Research (CFARs) across the United States. Participants in the clinical trial, called iENGAGE, achieved viral suppression in an average of just 63 days. The findings were presented in a poster at the Conference on Retroviruses and Opportunistic Infections (CROI 2019) in Seattle.

The findings from iENGAGE, which was funded by NIH's National Institute of Allergy and Infectious Diseases (NIAID), underscore the benefits of linking people with HIV to treatment services soon after diagnosis and highlight the importance of efforts to engage all people with HIV in care. Provision of effective HIV treatment resulting in sustained viral suppression is a critical component of efforts to end the HIV epidemic in the United States.

Notably, many iENGAGE participants had other medical conditions and unmet basic needs that can make adherence to medical visits and daily antiretroviral therapy (ART) difficult. About half of the study participants reported needing supportive services, including assistance with housing, employment, food and transportation. Mental health issues were also prevalent, with 31 percent of participants having depression and 30 percent having anxiety. Roughly one-third of participants reported high-risk alcohol use, and 18 percent reported substance use.

"Even when facing many other challenges in their lives, the majority of people engaged in HIV care can achieve viral suppression, benefiting their health and preventing transmission of the virus to others," said NIAID Director Anthony S. Fauci, M.D. "To end the HIV epidemic in the United States, we must ensure that effective HIV prevention and treatment strategies are accessible to all who need them, especially in the areas of the country with the highest HIV burden."

The iENGAGE trial was conducted at clinical trial sites in Baltimore; Seattle; Birmingham, Alabama; and Chapel Hill, North Carolina, participating in the CFAR Network of Integrated Clinical Systems (CNICS). Ten years ago, these sites recorded an approximately 60 percent rate of viral suppression among people new to HIV care.

The iENGAGE trial was designed to evaluate a behavioral intervention aimed at educating people newly diagnosed with HIV and reinforcing the importance of adherence to care. The 371 participants were enrolled within 14 days of initiating HIV medical care and randomly assigned to receive either the behavioral intervention plus standard care or standard care alone. The intervention, which combined two established approaches to enhance HIV medical visit adherence and ART adherence, comprised four in-person counseling sessions tailored to participants' individual needs, as well as phone support, during the first 48 weeks of treatment.

The intervention did not appear to affect viral suppression after 48 weeks. The high overall rate of viral suppression and the short average time to achieving suppression did not differ between the two study arms.

The iENGAGE investigators suggest that recent improvements in standard HIV care contributed to this overall high rate of viral suppression. These improvements include changes in HIV treatment guidelines to encourage early treatment for everyone diagnosed with HIV, an increased focus in clinical practice guidelines on retaining people in the HIV care continuum from diagnosis to viral suppression, and the inclusion of integrase inhibitors--a new potent and well-tolerated class of antiretroviral drugs--in first-line ART regimens. The researchers plan to assess viral suppression rates among iENGAGE participants at 96 weeks to evaluate whether the intervention improves long-term adherence to care.

The findings underscore the effectiveness of HIV care but also highlight the remaining challenges of closing treatment gaps by identifying strategies to engage and retain people with HIV in HIV treatment services. One potential approach could involve incorporating behavioral interventions into communities as part of rapid ART initiation programs, the iENGAGE investigators suggest.

Simple, inexpensive urban design interventions can increase well-being and social connections among city residents, finds a new case study from the Urban Realities Lab at the University of Waterloo.

Researchers found that green spaces and colourful, community-driven urban design elements were associated with higher levels of happiness, greater trust of strangers, and greater environmental stewardship than locations without those amenities.

"The urban design interventions we studied are relatively simple and low-cost, but show great potential to improve individuals' emotional and social lives," says Hanna Negami, lead author and PhD candidate in cognitive neuroscience. "Something as simple as adding greenery to a concrete lane or painting a rainbow crosswalk could help to enrich urban public spaces."

For the study, participants were taken on walking tours of Vancouver's West End neighbourhood and asked to complete a questionnaire via a smartphone application at six stops, including a pair of laneways (one green, one concrete), crosswalks (one painted rainbow, one standard zebra), and a pair of greenspaces (one wild community garden and one manicured greenspace).

The addition of greenspace and place-making initiatives can help promote social connections for citizens, and help to mitigate social isolation. Researchers hope that these findings will ultimately help improve the experiences of people living in cities.

"We know that the design of a city has direct, measurable, psychological impact on its citizens," says Colin Ellard, professor of psychology and director of the Urban Realities Lab. "We've been able to show how such impact can be measured and what it can tell us about good, psychologically sustainable design."

Scientists have shed light on how healthy cells develop by identifying the role of key molecules involved.

The components, known as R-loops, are formed during cell development and have been shown to play an important role in the process. The latest finding overturns previous thinking that R-loops, formed from the genetic material that makes up DNA, were harmful to cells.

Researchers found that R-loops work together with a group of cell proteins, known as Polycomb, to control genes that are important for development in humans and other mammals.

These genes regulate the fate and function of each cell in the body, for example helping to control whether they become neurons or muscle cells.

Findings from the study by the University of Edinburgh answer fundamental questions about cell biology. They could also inform research into health conditions that can occur when these processes misfire, and point towards new avenues of research towards drug treatments.

Further research could clarify the role of R-loops in diseases in which they are known to be associated. These include neurogenerative disorders such as Amyotrophic Lateral Sclerosis (ALS) and the developmental condition Fragile X.

Future studies may include examining R-loops in developing brain cells, with a view to informing the design of drugs to treat these neurological conditions. The findings also have important implications for some cancers, which are associated with faulty Polycomb proteins or the over-production of R-loops.

The study, published in Molecular Cell, was carried out in collaboration between the Max Delbruck Centre for Molecular Medicine in Berlin and the University of Edinburgh, supported by Wellcome and the European Research Council.

Dr Konstantina Skourti-Stathaki, of the University of Edinburgh's School of Biological Sciences, who led the study, said: "This new insight answers fundamental questions, opening new avenues for future research and possible routes towards drug treatments."

Marine scientists from WCS (Wildlife Conservation Society) and other groups examining the ecological status of coral reefs across the Indian and Pacific oceans have uncovered an unsettling fact: even the best coral reef marine parks contain less than half of the fish biomass found in the most remote reefs that lie far from human settlements.

The study titled "Global baselines and benchmarks for fish biomass: comparing remote reefs and fisheries closures" appears in the new edition of the journal Marine Ecology Progress Series.

"Searching for healthy reef fish communities to act as benchmarks required going far from shore to provide the ultimate control for human impacts. What we uncovered is that fishing has long-lasting seascape impacts, even when fishing has stopped in parks for decades," said Dr. Tim McClanahan, WCS Senior Conservationist and lead author of the study.

The researchers gathered data from a number of reef fish studies conducted between 2005 and 2016 on nearly 1,000 coral reefs to evaluate the effectiveness of remote reef baselines and nearshore benchmarks, management or access systems that are often used to evaluate the ecological status of marine ecosystems.

The coral reefs examined included both fishing closures (ranging from more than 15 years to 48 years in duration) and reef systems in sites that were more than 9 hours travel time from land-based markets. The mean distance to markets for remote areas was 39 hours of travel time compared to 2 hours for nearshore fisheries closures. Fish species from 28 families commonly found in coral reefs were included in the analysis. Sharks, generally wide-ranging species that are not always effectively protected through fishing closures, were excluded from the analysis. Thus, the finding could not be attributed to losses of sharks, species known to be highly vulnerable to fishing.

The analysis found that there was no significant change in a reef's biomass between those fish communities found in fishing closures that were approximately 15 years old and those that were nearly 50 years old. They did find that fishing closures had only 40 percent of the fish biomass contained in more remote reefs that had not experienced significant levels of fishing. Specifically, fishing closures used in the study had an average biomass of 740 kilograms per hectare, as opposed to 1,870 kilograms per hectare found in offshore reef sites. Remote reefs in tropical latitudes also contained more biomass than remote sites in subtropical locations; the authors also found that variables such as coral cover and light levels (related to depth) influenced reef's biomass of fish but in different ways for nearshore closure and remote reefs - indicating very different ecologies for coral parks and remote reefs.

The authors maintain that, while fishing closures are still an important tool for marine management in heavily fished seascapes, the new findings underline the difficulties of simulating wilderness in small marine parks.

McClanahan added: "We can see the important role that marine wilderness plays in protecting fish communities, a role that marine parks in nearshore locations are not able to simulate. Now, when we calculate fish baselines and biomass, we know what is truly being compared and lost in terms of conditions prior to human impacts."

DALLAS - March 6, 2019 - UT Southwestern researchers used cryo-electron microscopy (cryo-EM) to determine the near-atomic structure of the smallest membrane protein solved to date. Their work could lead to better immunotherapies in cancer and improved treatments for autoimmune diseases like lupus.

Cryo-EM - the technology credited with the "resolution revolution" underway in structural biology - uses a massive microscope to shoot a narrow stream of electrons through thin, flash-frozen samples. The STING (Stimulator of Interferon Genes) protein studied in UT Southwestern's 24/7 Cryo-Electron Microscopy Facility is about half the size of the next-smallest membrane protein determined, the researchers said.

UT Southwestern's Dr. Zhijian "James" Chen is a corresponding author on three studies published online today by Nature that describe this work. Two studies reveal the first full-length structure of the elusive STING protein attached to different molecules in the pathway. STING is a key member of an important pathway in innate immunity - the body's first line of defense against infections. The third study gives insight into the primitive function of the cGAS-STING pathway and underscores the importance of understanding its protein structure.

"Having the structure of the full-length STING protein at near-atomic resolution is very important for understanding innate immunity. It is also important for developing drugs that activate STING for cancer immunotherapy or inhibit the protein for treatment of autoimmune diseases, like lupus and arthritis," said Dr. Chen, Director of the Center for Inflammation Research, Professor of Molecular Biology, and a Howard Hughes Medical Institute Investigator at UT Southwestern.

Dr. Chen recently received the $3 million 2019 Breakthrough Prize in Life Sciences - one of the world's most prestigious biomedical awards - for his discovery of the cGAS enzyme. That DNA sensor launches the body's immune defense against infections and cancers in a pathway in which the STING protein is pivotal. The cGAS enzyme patrols the cell's interior and triggers an immune response when it encounters foreign DNA. It can also trigger autoimmunity when it finds self-DNA in areas of the cell where that genetic material should not exist. cGAS produces a small molecule called cGAMP (cyclic GMP-AMP), which binds to STING and launches an immune response.

"The cGAS-cGAMP-STING pathway leads to interferon production in mammals in response to DNA invasion," Dr. Chen said. Interferons - signaling proteins - tell cells to heighten their defenses against foreign invaders.

One of the two structural studies reports the first structure of STING in complex with TBK1 (Tank-Binding Kinase 1), the molecule that activates it and leads to production of specific interferons and other signaling molecules. The experiments, which used both human and chicken STING proteins, also reveal the tail end of STING, which was invisible in previous structures.

That tail is lacking in STING from sea anemones, the subject of Dr. Chen's third paper. Sea anemones are part of a group of invertebrates (creatures that lack a backbone) thought to exist for hundreds of millions of years before the first humans did. That study finds that STING in sea anemones can activate an immune response through autophagy. Often called cellular housekeeping, autophagy clears away unwanted molecules - in this case pathogens - within the cell by breaking them down for recycling. Humans have the c-GAS-STING-to-autophagy immune pathway as well as the c-GAS-STING-to-interferon pathway that sea anemones lack.

That finding led Dr. Chen to suggest that, as in a scorpion, the "STING is in the tail." More seriously, he said the study suggests that autophagy is a primordial (primitive) pathway for immunity that developed earlier than the interferon pathway found in humans.

"STING is by far the smallest membrane protein that has been solved to near-atomic resolution using cryo-EM," said Dr. Xiaochen Bai, a co-corresponding author of the two STING structure papers. "Therefore, this accomplishment represents another milestone in the history of cryo-EM structural determination, and indicates that cryo-EM has become a powerful tool to study small membrane-embedded biological macromolecules." Dr. Bai is an Assistant Professor of Biophysics and Cell Biology and a Virginia Murchison Linthicum Scholar in Medical Research.

The third corresponding author, Dr. Xuewu Zhang, Associate Professor of Pharmacology and Biophysics, pointed out some benefits of cryo-EM.

"The longtime preferred technology for structural biology - X-ray crystallography - requires molecules to be crystallized in order to determine their structures. Membrane proteins have been notoriously difficult to crystallize," explained Dr. Zhang, a Virginia Murchison Linthicum Scholar in Medical Research. "Even when they do crystallize, they often diffract an X-ray beam very weakly, making it difficult to derive high-resolution structures from the diffraction data. These new studies demonstrate the special advantages of cryo-EM in eliminating the need to grow crystals. Another advantage of cryo-EM is that it is possible to capture multiple conformations - or dynamic structures - from one sample, which allows us to generate 'movies' to understand how macromolecules act," he said.

 
Ithaca, NY--Using data on 77 North American migratory bird species from the eBird citizen-science program, scientists at the Cornell Lab of Ornithology say that, in as little as four decades, it may be very difficult to predict how climate change will affect migratory bird populations and the ecosystems they inhabit. Their conclusions are presented in a paper published in the journal Ecography.
 

"Climates have natural variation and we're moving rapidly into territory where the magnitude of climate change will consistently exceed this variation," says lead author and Cornell Lab researcher Frank La Sorte. "There will be no historic precedent for these new climates, and migratory bird populations will increasingly encounter 'novel' climatic conditions. The most likely outcome will be a period of ecological disruption as migratory birds and other species try to respond or adapt to these new conditions."
 

Cornell Lab scientists generated new climate models incorporating multiple sources of data. This produced a timeline indicating when and where migratory bird populations are likely to be significantly affected by novel climates during each phase of their annual life cycles. It's not that far off:
 

-- Last 40 to 50 years of this century. During this period, migrants such as the Black-and-white Warbler, are likely to first experience novel climates on their tropical wintering grounds (regions south of Florida) and also during the late summer on their breeding grounds in the North American temperate zone (above the nation's midsection).

-- First 50 years of the next century. This is when novel climates are likely to emerge for birds that winter in the subtropics--the southern half of the U.S. 

The study authors conclude that by the middle of the next century migratory bird populations will experience novel climates during all phases of their annual life cycles.

La Sorte and co-authors considered minimum and maximum temperatures, and precipitation in the Western Hemisphere, week by week, for 280 years, from 2021 through 2300, under the worst-case scenario: continued high levels of greenhouse gas emissions. La Sorte says this is the first study to use a combination of climate variables to estimate when novel climates will first emerge, and it is the first study to examine the full annual cycle implications for a large number of migratory bird species.

"It's not surprising that novel climates will be first encountered in the tropics," says La Sorte. "There's little variation in tropical climates, so even a small change in climate can generate highly novel conditions. It is surprising to find that on these species' breeding grounds, novel climates will emerge roughly 40 to 50 years earlier during the second half of the breeding season. This is a critical phase of these species' life cycle when adult and juvenile birds are transitioning from breeding to migration."
 

The three data sources used for the study were 13 years of observations from the eBird program (2004-2016), climate projections from the most recent International Panel on Climate Change report, and NOAA data used to estimate climatic variation over a 60-year period. What constitutes a "novel" climate will depend on each region's historical norms for that season.
 

"One reason we are considering novel climates is that current ecological projections under climate change tend to be unrealistic," explains La Sorte. "We can't reliably predict how birds or other species will respond to novel climates. In this study, we document when in the future this uncertainty is likely to become a significant factor that could adversely affect migratory bird populations."
 

When naturalist Charles Darwin stepped onto the Galapagos Islands in 1835, he encountered a bird that sparked a revolutionary theory on how new species originate. From island to island, finches had wildly varied beak designs that reflected their varied diets. The so-called Darwin's finches are an emblem of adaptive radiation, which describes when organisms from a single lineage evolve different adaptations in response to competitors or predators.

Scientists think that adaptive radiation generates much of the biodiversity on Earth, yet most studies focus on groups that have already diversified. A new study took the opposite approach.

University of Utah biologists experimentally triggered adaptive radiation; they used host-specific parasites isolated on individual pigeon "islands." The scientists showed that descendants of a single population of feather lice adapted rapidly in response to preening, the pigeons' main defense. They found that preening drives rapid and divergent camouflage in feather lice (Columbicola columbae) transferred to different colored rock pigeons (Colombia livia). Over four years and 60 generations, the lice evolved heritable color differences that spanned the full color range of the lice genus found on 300 bird species worldwide.

"The changes in color that we saw are as light as the lightest species and as dark as the darkest species in the entire genus--and this genus has been evolving for millions of years," said Sarah Bush, associate professor in biology at the U and lead author of the paper. "The changes and selection that happens day to day are the same patterns that we see over millions of years."

This is the first study to show that the evolutionary changes that occurred within a single species (microevolution) echoed changes in color among different species that diverged millions of years ago (macroevolution).

"People have been trying to bridge micro- and macro- evolution for a long time," said Dale Clayton, professor in biology at the U and co-author of the paper. "This study actually does it. That's a big deal."

The study published online on March 5 in the journal Evolution Letters.

Parasite island

Adaptive radiation is famous on archipelagos. From Hawaiian silverswords to Caribbean lizards, plant and animal lineages diversify rapidly when the ocean limits gene flow and movement between landforms. Parasites are restricted to individual host species and likely adapt and diversify like organisms restricted to islands. The host's defense seems to be the main driver of adaptive radiation in parasites, yet scientist have never tested this hypothesis experimentally.

The team worked with a host-parasite system that was uniquely easy to manipulate: rock pigeons (C. livia) and their feather lice (C. columbae). The sesame seed-sized lice are feather specialists; they never touch the bird's skin and have special gut bacteria to digest the keratin-rich down feathers. Pigeons mainly defend themselves by preening and lice hide from prying beaks by matching the color of the feathers, a strategy known as cryptic coloration.

In order to test whether preening drove the evolution of cryptic coloration, the team needed to prove that three things were happening: First, that there was a selective pressure driving the color changes. Second, that there was genetic variation for different color phenotypes. Third, that the color change needed to be heritable, passed down from parent to offspring.

Preening is a selective pressure? Genetic variation? Check!

First, the biologists showed that the birds were visually-preening the lice. They suspected this was the case--in 2010, Bush led a study that found that birds with light feathers have light-colored lice, and birds with dark feathers had dark colored lice. For the current study, the biologists began with a single population of feather lice and painted their backs with nail polish-like paint: half with black paint, and half with white paint. They then evenly distributed the lice to eight black pigeons and eight white pigeons, let the birds preen for 48-hours before counting how many black and white lice were left on the pigeons.

They found that lice painted the "wrong" color--black lice on white feathers and vice versa--were 40 percent more likely to be preened than the cryptically colored lice. They then did the same experiment but with black and white pigeons who were unable to preen by wearing harmless plastic bits on their beaks. After 48 hours, they found that the birds with impaired preening had no difference between cryptic and conspicuous lice in their feathers. This demonstrated that preening was indeed a selective pressure for lice survival.

To test whether preening selects for different colors of the lice, they infested 96 lice-free rock pigeons with unpainted lice: 32 white, 32 black and 32 grey pigeons received 25 lice each. Within each color, half of the birds preened normally while half wore the bits that impaired preening. The lice stayed on these birds over the entire course of the experiment--four years, resulting in about 60 generations of offspring. Every six months the biologists sampled the lice and took photographs to analyze the luminosity (the relative lightness or darkness) of the parasites, then put them back on the birds.

The luminosity of lice on white and black pigeons changed significantly relative to the color of lice on the control grey pigeons--the lice on white pigeons got dramatically lighter, while the lice on black birds got darker. By the end of the experiment, the lightest lice on white pigeons were as light as the lightest species of lice in the entire genus.

"Look at the range of colors. I mean it just went wham! The color range overlaps with other species of louse in just four years," said Clayton. "Compared to evolutionary time that's not even the bat of an eyelash."

Is the color change heritable? Check!

To test whether the color changes were heritable, Bush and the team needed to verify that the offspring of the lice were similar in color to their parents. They took lice from 12 pigeons who could preen normally and placed them on gray pigeons to reproduce. First, they needed to distinguish the parents from their offspring.

So, they gave the lice tiny haircuts. Co-lead author Scott Villa, a former postdoctoral researcher at the U who is now a postdoctoral fellow in the Department of Biology at Emory University, permanently marked the parent lice by using tiny scissors to trim miniscule bristles, called setae, off of one side of the lice. They then put the lice with these unique haircuts on 12 gray pigeons with impaired preening and waited 48 days. Then they photographed and analyzed the colors of both the parents and later the offspring, which did not have haircuts.

The luminosity of the parents was highly correlated with the luminosity of the offspring, meaning that color was heritable.

Impact lies beyond lice

Although the scientists expected that preening would eventually drive divergent camouflage in the lice, they were surprised by how rapid the changes occurred. This probably applies to other pathogens that diversify in response to host defenses, including human pathogens responding to our immune system.

"The cool thing about this project is what we're observing in terms of evolutionary response isn't unique to lice, it would apply to anything with DNA," said Bush.

The biologists are working on a second experiment in which they put feather lice on differently-sized pigeon breeds to see whether preening selects for different-sized lice. The lice may evolve divergent sizes so extreme that they are unable to mate, a significant step in the origin of a new species. Stay tuned.

A large breakthrough has been made in the genetic understanding of mouth ulcers which could provide potential for a new drug to prevent or heal the painful lesions. Mouth ulcers affect up to 25 per cent of young adults and a higher proportion of children. Previous research has shown that mouth ulcers are partially heritable, but until now there has been little evidence linking specific genes or genomic regions to mouth ulcers.

The study, carried out by an international team of scientists and led by researchers at the University of Bristol, attempted to pinpoint areas of the genome associated with triggering mouth ulcers by looking systematically across the DNA code. By looking at mouth ulcers in different populations in the UK, USA and Australia the researchers aimed to find genes which were consistently linked to mouth ulcers. The research is published today [Tuesday 5 March] in Nature Communications.

The team identified genetic variants associated with the condition by analysing genetic data derived from over 450,000 participants in the UK Biobank and replicated these findings in over 350,000 participants in USA-based data collection 23andMe. They discovered 97 common genetic variations across the genome that predispose people to mouth ulcers. The study went on to look at three further studies, including Bristol's Children of the 90s (ALSPAC) study, which showed confirmatory results. These variations are enriched in genes that have previously been linked to regulation of the body's immune system.

Tom Dudding, Wellcome Trust Clinical Research Fellow in the Bristol Medical School: Population Health Sciences (PHS) and Bristol Dental School and joint-first author of the paper, said: "Currently, there are few satisfactory drug treatments for mouth ulcers as current medication options are non specific and can lead to side effects. The field has gone from very little genetic understanding of mouth ulcers to having up to 97 areas of the genome which may provide an excellent basis for future research.

"Importantly, our findings also show that several of the genes related to mouth ulcers are in pathways which are already targeted by drugs that are used to treat other diseases such as rheumatoid arthritis and psoriasis. There is the potential that drugs like these could be used to treat mouth ulcers, although further work is required to demonstrate this."

In a groundbreaking Cornell-led study illuminating the extensive scope of mass incarceration in the U.S., nearly 1 in 2 Americans have had a brother or sister, parent, spouse or child spend time in jail or prison - a far higher figure than previously estimated.

The study is the first to accurately measure the share of Americans - 45 percent - who have ever had an immediate family member jailed or imprisoned for one night or more. The researchers had assumed they would find half that rate.

"The core takeaway is family member incarceration is even more common than any of us - all of whom are experts in the field - had anticipated," said Christopher Wildeman, professor of policy analysis and management and a co-author of the study, which appeared March 4 in Socius.

"This really is an issue that affects all of society," added lead author Peter Enns, associate professor of government. Their Cornell co-authors are doctoral candidates Youngmin Yi, M.A. '16, and Alyssa Goldman '07, M.A. '16.

The figures are even higher for African-Americans and people with low education levels; for those groups, nearly 3 in 5 have had an immediate family member incarcerated, the team found. And siblings were the most common immediate family member to be incarcerated, the researchers said - another surprise finding - and a trend about which not much is known.

"Having an immediate family member in prison instead of in the home can have a major effect on a person and can be extremely disruptive," said Enns.

"This survey really shows who the victims of mass incarceration are: the folks who have to manage households and grow up absent a loved one," said Wildeman, director of the Bronfenbrenner Center for Translational Research.

More-advantaged groups are not immune to the trend, the study found. While college-educated whites experience family incarceration at a much lower rate than the less-educated and people of color, 1 in 6 - 15 percent - have had that experience. "That breaks pretty sharply from the standard narrative that we've heard in the research community and in popular discourse, about how white, college-educated folks are completely insulated from those risks," said Wildeman. "And, indeed, this provides further evidence that mass incarceration is a profoundly American phenomenon and something that we as a society must confront together."

Even though all groups are affected, education does somewhat insulate whites from having a family member imprisoned. As their level of education goes up, their level of incarcerated family members goes down.

But that is much less true for African-Americans; the chances an African-American will have a family member jailed or imprisoned stays about the same even if she is well-educated. About 70 percent of people who didn't finish high school have had a family member incarcerated; it's 71 percent for those with a high school equivalent; and 55 percent for those who have a college education.

The research, which grew out of a theme project sponsored by Cornell's Institute for the Social Sciences, is the first to capture both jail time and prison time for family members. And it represents people who are often overlooked in national surveys - such as young adults, households with a low socio-economic status, those without internet access and Spanish speakers - thanks to study's design: participants were able to take the survey online or by phone, in English or in Spanish.

The researchers asked a nationally representative sample of more than 4,000 people whether members of their immediate family (a parent, sibling, spouse or domestic partner, stepsiblings or foster family) or extended family (including grandparents, grandchildren, cousins, nieces, nephews or in-laws) have ever been held in jail or prison for a night or more, and for how long.

The participants were also asked follow-up questions about their experiences with and opinions of the police and the criminal justice system, health and well-being, civic and political engagement, and drug and alcohol use.

The researchers will dig into that data in later studies - and they invite other researchers to do so as well. They've made their data publicly available via Cornell's Roper Center for Public Opinion Research, of which Enns is executive director, to allow others to both see what else the data show and confirm the findings for themselves.

The researchers hope the study will destigmatize the incarceration of family members.

"I hope that it will help folks see that this is more a structural issue than a behavioral one," Wildeman said. "And I hope that it would drive home just how much more we can learn when we do the work to get surveys that explicitly focus on crime and criminal justice contact."

Very small steps make a big difference to researchers who want to create large wafers of two-dimensional material.

Atom-sized steps in a substrate provide the means for 2D crystals growing in a chemical vapor furnace to come together in perfect rank. Scientists have recently observed this phenomenon, and now a Rice University group has an idea why it works.

Rice materials theorist Boris Yakobson and researcher Ksenia Bets led the construction of simulations that show atom-sized steps on a growth surface, or substrate, have the remarkable ability to keep monolayer crystal islands in alignment as they grow.

If the conditions are right, the islands join into a larger crystal without the grain boundaries so characteristic of 2D materials like graphene grown via chemical vapor deposition (CVD). That preserves their electronic perfection and characteristics, which differ depending on the material.

The Rice theory appears in the American Chemical Society journal Nano Letters.

The investigation focused on hexagonal boron nitride (h-BN), aka white graphene, a crystal often grown via CVD. Crystals nucleate at various places on a perfectly flat substrate material and not necessarily in alignment with each other.

However, recent experiments have demonstrated that growth on vicinal substrates - surfaces that appear flat but actually have sparse, atomically small steps - can align the crystals and help them merge into a single, uniform structure, as reported on arXiv. A co-author of that report and leader of the Korean team, Feng Ding, is an alumnus of the Yakobson lab and a current adjunct professor at Rice.

But the experimentalists do not show how it works as, Yakobson said, the steps are known to meander and be somewhat misaligned.

"I like to compare the mechanism to a 'digital filter,' here offered by the discrete nature of atomic lattices," he said. "The analog curve that, with its slopes, describes a meandering step is 'sampled and digitized' by the very grid of constituent atomic rows, breaking the curve into straight 1D-terrace segments. The slope doesn't help, but it doesn't hurt. Surprisingly, the match can be good; like a well-designed house on a hill, it stands straight.

"The theory is simple, though it took a lot of hard work to calculate and confirm the complementarity matching between the metal template and the h-BN, almost like for A-G-T-C pairs in strands of DNA," Yakobson said.

It was unclear why the crystals merged into one so well until simulations by Bets, with the help of co-author and Rice graduate student Nitant Gupta, showed how h-BN "islands" remain aligned while nucleating along visibly curved steps.

"A vicinal surface has steps that are slightly misaligned within the flat area," Bets said. "It has large terraces, but on occasion there will be one-atom-high steps. The trick by the experimentalists was to align these vicinal steps in one direction."

In chemical vapor deposition, a hot gas of the atoms that will form the material are flowed into the chamber, where they settle on the substrate and nucleate crystals. h-BN atoms on a vicinal surface prefer to settle in the crook of the steps.

"They have this nice corner where the atoms will have more neighbors, which makes them happier," Bets said. "They try to align to the steps and grow from there.

"But from a physics point of view, it's impossible to have a perfect, atomically flat step," she said. "Sooner or later, there will be small indentations, or kinks. We found that at the atomic scale, these kinks in the steps don't prevent h-BN from aligning if their dimensions are complementary to the h-BN structure. In fact, they help to ensure co-orientation of the islands."

Because the steps the Rice lab modeled are 1.27 angstroms deep (an angstrom is one-billionth of a meter), the growing crystals have little trouble surmounting the boundary. "Those steps are smaller than the bond distance between the atoms," Bets said. "If they were larger, like two angstroms or higher, it would be more of a natural barrier, so the parameters have to be adjusted carefully."

Two growing islands that approach each other zip together seamlessly, according to the simulations. Similarly, cracks that appear along steps easily heal because the bonds between the atoms are strong enough to overcome the small distance.

Any path toward large-scale growth of 2D materials is worth pursuing for an army of applications, according to the researchers. 2D materials like conductive graphene, insulating h-BN and semiconducting transition metal dichalcogenides are all the focus of intense scrutiny by researchers around the world. The Rice researchers hope their theoretical models will point the way toward large crystals of many kinds.

New University of Liverpool research, published in Pediatrics, highlights the negative influence that social media has on children's food intake.

Current research shows celebrity endorsement and television advertising of unhealthy foods increases children's intake of these foods. However, children are increasingly exposed to marketing through digital avenues, such as on social media, and the impact of marketing by YouTube video bloggers (vloggers) on these outcomes has, until now, not been known.

According to a recent report by Ofcom children in the UK now access social media more than ever before. Approximately 93% of 8-11-year-olds go online, 77% use YouTube and 18% have a social media account. In older children (12-15-year-olds), 99% go online, 89% use YouTube and 69% have a social media account. Both age groups watch YouTube vloggers.

Vloggers' influence

PhD student Anna Coates, from the University's Appetite and Obesity research group, conducted a study to examine the effect of social media marketing of snack foods (healthy and unhealthy), via vloggers' Instagram pages, on children's snack intake.

During the study 176 children, aged between 9 and 11 years, were randomly split into three equal groups and were shown artificially created, but realistic, Instagram pages of popular vloggers (each has millions of followers). One group was shown images of the vlogger with unhealthy snacks, the second group was shown images of the vlogger with healthy snacks and the third group was shown images of the vlogger with non-food products. The participants' subsequent intake of snacks (healthy and unhealthy options) were measured.

Children in the group that viewed the unhealthy snack images consumed 32% more kcals from unhealthy snacks specifically and 26% more kcals in total (from healthy and unhealthy snacks) compared with children who saw the non-food images. There was no significant difference in total kcal intake, or healthy snack kcal intake, between children who saw the Instagram profile with healthy images and those who saw the non-food images.

Impactful and exploitative

Of the study Anna Coates, said: "These findings suggest that the marketing of unhealthy foods, via vloggers' Instagram pages, increases children's immediate energy intake. The results are supported by celebrity endorsement data, which show unhealthy food endorsements increase children's unhealthy food intake, but healthy food endorsements have little or no effect on healthy food intake.

"Young people trust vloggers more than celebrities so their endorsements may be even more impactful and exploitative. Tighter restrictions are needed around the digital marketing of unhealthy foods that children are exposed to, and vloggers should not be permitted to promote unhealthy foods to vulnerable young people on social media."

CLEMSON, South Carolina - New research published today in Scientific Reports has devised a way to track tiny message-carriers in the brain that could prove useful in diagnosing and treating injuries, infections or diseases.

The study, from assistant professor David Feliciano's lab in Clemson's College of Science, uses a glowing mouse - appropriately dubbed the "TIGER mouse" - to trace the movement of information-rich particles found in bodily fluids throughout the body, called extracellular vesicles (EVs).

The Transgenic Inducible Green fluorescent protein EV Reporter (TIGER) mouse serves as one small step for researchers toward understanding the variety of EV functions. The vesicles contain "messages" - in the form of short RNA sequences, or microRNAs - that act as instructions for intercellular communication in everything from inducing an immune response to assisting in neuron formation. The potential functions of EVs are endless, as the instructions doled out by the vesicles are dependent on the cells in which they originate.

By employing the TIGER mouse, the researchers hope to more easily pinpoint these cell types that release EVs.

"Up until this point, the most that someone could do is study EVs in cell lines, study them in vitro or transplant them into mice and study them that way. This way, we can study a more internal effect that EVs have in a model system because these mice are bred with a reporter system in their genes," said Victoria Neckles, a graduate student and first author on the study.

To generate the mouse, the researchers relied on Cre-lox recombination, a type of gene editing that can activate or inactivate specific genes by injecting a set of genetic instructions, called a cassette, into a single cell of a mouse embryo. Once injected, the cassette can integrate into the mouse's genome, and as the cells multiply, the cassette becomes one with the maturing mouse.

In Neckles' study, the researchers engineered a cassette that can cause EVs to glow green via a protein called green fluorescent protein. When the TIGER mouse is mated with another mouse that has a unique enzyme - Cre recombinase - then the green fluorescence is activated in the mice's pups. The process can become more precise by mating the TIGER mouse to a Cre mouse in which the Cre recombinase is only activated in certain cell-types, meaning only certain cells will glow in the pair's offspring while others will not. In a third case, the researchers can control when the cells begin to glow by supplementing the pups' diet with a drug called tamoxifen, which turns on the fluorescence. While the change isn't visible to the naked eye, the florescence can be seen by photographing the mouse pups with a fluorescent scanner or an ultraviolet flashlight.

"The utility of this is that instead of having a pea soup of lots of different things, you have individual components that are labeled, and we know where they came from," Feliciano said. "The reason that's important is because it allows us to see how different cells contribute in different physiological or pathophysiological states."

Previous research in the Feliciano lab found that extracellular vesicles are released by neural stem cells and then taken up by microglia, the immune cells of the central nervous system that are the first line of defense against infection, damage or inflammation in the brain. That study signified that extracellular vesicles could potentially be engineered to direct microglia to diseased or damaged portions of the brain, where they could aid in the immune response.

With the development of the TIGER mouse, Neckles was able to uncover another cell-type that releases EVs: astrocytes, the glial cells of the brain and spinal cord that pass nutrients, maintain ion balance and repair nervous system injuries, among other functions.

"What we figured out using the mouse is that the astrocytes release EVs that help the microglia mature," Neckles said. "We don't know the precise mechanism by which this occurs, but thanks to the mouse, we can identify at least a few different sources of EVs and interpret how they function differently."

The significance of this work, Feliciano says, is to generate an "atlas" that could aid in the diagnosis and treatment of a variety of diseases.

"If you have a cell type, and you know how it is changing in any disease and how the EVs that it releases change, then you basically have an atlas - a map of information for each vesicle for each source," Feliciano said. "So, somebody comes into the clinic, and they have a certain disease with certain symptoms. You could imagine taking their vesicles from a blood sample, and you basically have a barcode or a fingerprint that matches our known barcodes. And we could say, 'This looks like a lot of astrocyte EVs, a lot of sick EVs.' And we could diagnose disease based on that."

After five years since the study's conception, and after thoroughly vetting every piece of data to develop a transgenic mouse, Feliciano says his team is in a regrouping phase.

"Now that we've figured things out, we get to ask, 'What do we want to study the most?' We have the tool that nobody has, so what question is the most important question that we can answer and contribute to?" Feliciano said.

"The goal is to help everybody reach their goals. When everybody wins, you win. Now, other labs that study EVs can benefit from this tool," he added.

MINNEAPOLIS - People who are witnessed by a bed partner to have stopped breathing during sleep may have higher accumulations of an Alzheimer's disease biomarker called tau in an area of the brain that helps with memory, according to a preliminary study released today that will be presented at the American Academy of Neurology's 71st Annual Meeting in Philadelphia, May 4 to 10, 2019.

Obstructive sleep apnea is a condition that involves frequent events of stopped breathing during sleep, although an apnea may also be a single event of paused breathing during sleep.

Tau, a protein that forms into tangles, is found in the brains of people with Alzheimer's disease.

"A person normally has fewer than five episodes of apnea per hour during sleep," said study author Diego Z. Carvalho, MD, of the Mayo Clinic in Rochester, Minn., and a member of the American Academy of Neurology. "Bed partners are more likely to notice these episodes when people stop breathing several times per hour during sleep, raising concern for obstructive sleep apnea. Recent research has linked sleep apnea to an increased risk of dementia, so our study sought to investigate whether witnessed apneas during sleep may be linked to tau protein deposition in the brain."

The study involved 288 people age 65 and older who did not have cognitive impairment. Bed partners were asked whether they had witnessed episodes of stopped breathing during sleep.

Participants had positron emission tomography (PET) brain scans to look for accumulation of tau tangles in the entorhinal cortex area of the brain, an area of the brain in the temporal lobe that is more likely to accumulate tau than some other areas. This area of the brain helps manage memory, navigation and perception of time.

Researchers identified 43 participants, 15 percent of the study group, whose bed partners witnessed apneas when they were sleeping.

Researchers found those who had apneas had on average 4.5 percent higher levels of tau in the entorhinal cortex than those who did not have apneas, after controlling for several other factors that could affect levels of tau in the brain, such as age, sex, education, cardiovascular risk factors and other sleep complaints.

"Our research results raise the possibility that sleep apnea affects tau accumulation," said Carvalho. "But it's also possible that higher levels of tau in other regions may predispose a person to sleep apnea, so longer studies are now needed to solve this chicken and egg problem."

Limitations of the study included its relatively small sample size and preliminary nature of the study requiring future validation. Furthermore, a lack of sleep studies to confirm the presence and severity of sleep apnea and a lack of information regarding whether or not participants were already receiving treatment for sleep apnea is another serious limitation.