Earth

LAWRENCE -- Research published today in JAMA Network Open by investigators at the University of Kansas and KU Medical Center finds pregnant mothers who daily consumed 600 milligrams of docosahexaenoic acid (DHA) -- an omega-3 fatty acid found in prenatal vitamins, fish-oil supplements and fish meat -- protected their offspring from the blood pressure-elevating effects of excessive weight in early childhood.

Women with low-risk pregnancies in the Kansas City area were enrolled in the study at the University of Kansas Medical Center's Maternal and Child Nutrition and Development Lab between March 2006 and September 2009. Half were randomly assigned to a daily prenatal supplement of 600 milligrams DHA, and half were given a placebo. The primary outcomes of the intervention were pregnancy outcome and child development through age 6; blood pressure measured longitudinally at 4, 4 1/2, 5, 5 1/2 and 6 years of age in 171 children was a secondary outcome.

The key finding was that being overweight and obese were associated with the expected higher blood pressure in the placebo group but not in the group whose mothers were assigned to DHA. Obese and overweight children of mothers in the placebo group had a large mean increase of 3.94 mm Hg for systolic BP and 4.97 mm Hg for diastolic BP compared with overweight/obese children of DHA-supplemented mothers. These differences were statistically significant.

While many prenatal supplements in the U.S. contain DHA, most have much less than 600 milligrams. The researchers emphasize the amount of prenatal DHA needed to protect against the rise in blood pressure in children with excessive weight is not known. However, being overweight and obese are large problems among U.S. children with nearly 1 in 5 school-age children and young people aged 6 to 19 years obese, according to the Centers for Disease Control 2015-2016 data.

"This research is aimed at expectant mothers and pediatricians who wonder what you can do prior to the birth of your child to optimize health and behavior outcomes," said co-author John Colombo, KU professor of psychology, director of KU's Life Span Institute and currently KU's interim vice chancellor for research. "There's a phenomenon called 'developmental programming,' and researchers have studied effects of the prenatal environment on long-term outcomes since World War II. The prenatal environment programs a fetus' metabolism for what to expect in the postnatal environment. Part of DHA's known effects may be in programming cardiac function that preserves normal blood pressure in the case of high postnatal weight gain."

"Prenatal DHA exposure appears to program the developing fetus to be protected against the blood pressure-elevating effects of obesity in childhood," said co-author Susan Carlson, AJ Rice Professor of Nutrition in the KU Department of Dietetics and Nutrition at the KU Medical Center.

The investigators believe lower blood pressure at age 6 might extend beyond childhood.

"It is known that blood pressure tracks over time such that people with higher BP early in life are more likely to have higher BP later in life," Carlson said.

Colombo and Carlson's colleagues on the study were Elizabeth Kerling, Jamie Hilton and Jocelynn Thodosoff of the KU Department of Dietetics & Nutrition and Jo Wick of the Department of Biostatistics at KU's School of Medicine.

The National Institutes of Health supported the phase 3 clinical trial, which also is part of KU's Intellectual and Developmental Disabilities Research Center.

Previous reports of the trial found that maternal DHA supplementation reduced birth before 34 weeks' gestation and was associated with higher fat-free body mass at age 5.

The good thing about the short Antarctic summer is it's a lot like a Midwest winter.

But for wingless flies, that's also the bad thing about Antarctic summers. The flies and their eggs must contend with an unpredictable pattern of alternating mild and bitterly cold days.

University of Cincinnati biologist Joshua Benoit traveled to this Land of the Midnight Sun to learn how Antarctica's only true insect can survive constant freezing and thawing. He found that the midges have surprising adaptations for life in their wintry realm.

Benoit and his students presented their findings in January at the Society for Integrative and Comparative Biology conference in Tampa, Florida.

Smaller than a Tic Tac, Belgica antarctica is the largest land animal found in Antarctica. Larvae resemble plum-colored worms. Adults are black and antlike.

At some point in their evolution, the little midges lost their wings -- possibly to cope with the notorious Antarctic winds. Since they eat abundant algae and never travel far from where they're hatched, the flies don't need to fly.

Finding them isn't hard.

"You crawl around on the ground and dig in dirt, algae and moss until you find them," said Benoit, an assistant professor in UC's McMicken College of Arts and Sciences. "And because of the penguin colonies, there's a lot of penguin excrement, too."

Benoit has undertaken three scientific missions to Antarctica, conducting research out of Palmer Station in the U.S. Antarctic Program. Previously, he studied Antarctic ticks that feed on penguins and other sea birds.

For his latest project, Benoit examined the molecular mechanisms underlying the fly's reproduction. Like other midges, adult flies mate in big swarms during the brief Antarctic summer. The females lay eggs that hatch about 40 days later. Then the newborn flies spend the next two years developing as larvae, entombed for much of the year in ice.

It's only in their last week of life that they spread their wings, so to speak, as fully formed adults. They die just days after mating.

Scientists call them "extremophiles" for their ability to survive in extreme conditions.

"It could be living at a high elevation on a mountain -- that's extreme. Or if you live in an extremely salty environment," he said.

Few creatures can survive the hostile conditions of Antarctica, Benoit said. The continent is home to a menagerie of tiny organisms such as mites and nematodes. It's the tiny fly's ability to withstand cold and dehydration that makes it an extremophile of Olympic proportions.

Scientists know that the midge larvae stay sheltered from the worst of Antarctica's blinding sun and bracing cold by remaining under a protective layer of moss and soil. Here the temperature and humidity are relatively constant.

But during the Antarctic summer, daily temperatures can soar into the 40s and dip well below freezing. UC researchers wanted to know how the midge's eggs tolerate such big temperature swings.

"The females secrete this clear jelly around the eggs. Essentially, it's like antifreeze," UC student and study lead author Geoffrey Finch said. "It acts as a temperature buffer against those fluctuations to help them survive."

The gel also helps the eggs survive Antarctica's other defining climate feature -- its dryness. Antarctica is home to the world's biggest desert. Belgica can survive even after losing more than 70 percent of its water content. By comparison, studies have found that people begin to suffer cognitive impairments when we lose as little as 2 percent of our water content through dehydration.

"So having all these unique adaptations is what allows them to live in this extreme environment," Benoit said.

LAWRENCE -- When NFL player Colin Kaepernick took a knee during the national anthem to protest police brutality and racial injustice, the ensuing debate took traditional and social media by storm. University of Kansas researchers have found that tweets both in support of and opposed to the protests can influence how young people think about the issue and, like in many aspects of life, the messenger's race matters.

A sample of white millennial participants viewed real tweets on the topic, then answered questions about their perceptions of the issue and about who tweeted the messages, Eye-tracking equipment mapped the time participants spent reading each post, used as a proxy for their attention to the tweets. According to the eye-tracking data, participants looked longer at messages from white Twitter users, while self-reported data showed that they would be more likely to engage with black Twitter users on the topic.

"Twitter is an important outlet. We know that," said Joseph Erba, assistant professor journalism & mass communications and lead author of the study. "We also know from traditional advertising and marketing literature that the visual identification of the communicator matters as well. What we were interested to see is if the visual identification of a Twitter user influences how people perceive the message. It does."

Erba co-wrote the study with Yuchen Liu, graduate student, and Mugur Geana, associate professor of journalism & mass communications. They will present their research at the International Communication Association conference in May. The research was conducted at CEHCUP's Experimental Media Research Laboratory in the School of Journalism & Mass Communications.

A few weeks before completing the experiment, researchers gave participants a questionnaire to assess their perceptions of race and feelings about the NFL protests. For the experimental component of the study, the research team gathered real tweets about the topic, both in support of and against the protests. They constructed new Twitter identities to present the tweets featuring pictures of users who were either a white man or woman or a black man or woman. During the experiment, participants were exposed to tweets either for or against the NFL protests, delivered by one of the gender/race combinations of Twitter users. Afterward, participants took a post-test asking the same questions about their perceptions of the protests and feelings regarding black Americans. They also answered additional questions about the tweets and the person tweeting.

Eye-tracking software indicated they looked the longest at tweets from white people, especially males. However, when asked after the study who they thought was most credible on the topic, and who they would most likely engage with, participants rated black users, especially male, the highest. That contradiction indicates race can influence audience attention and that self-reported data should be viewed cautiously, Erba said.

Respondents also widely reported changing their feelings about the protests after reading the tweets. Those who were exposed to tweets in favor of the protests had an improved view of the subject, and the inverse was true for those who saw tweets against the movement compared with their views about the protest about three weeks earlier. Each participant saw four tweets.

"Four little tweets were enough to significantly change their views on the NFL protests. We did not find a difference in their attitudes toward black people or racism though," Erba said. "We think it was because the tweets were directly about the protests, and making the connection to larger issues may have just been too much."

A number of communication theories are likely at play and can help explain why participants reported more credibility for tweets from users they looked at less. Social identification theory posits that individuals are more attracted to what people who look like them have to say than those who don't. Identification theory holds that people will provide information to help ensure they are viewed as how they want to be perceived by others, as opposed to how they really are. The latter likely helps explain why participants said black Twitter users were viewed as more credible on the topic. Race is a central issue in the protests and subsequent debate, and the research found that race of a Twitter user matters. White respondents reported that black Twitter users were more credible.

"Yet, if you look at the (2016) elections, 40 percent of white millennials voted for Trump," Erba said. In the study, they looked more at people who looked like them, but when asked directly, said they supported black men."

The majority of NFL players are black, and police brutality, the central issue of the protests, disproportionately affects black Americans, especially men. Therefore, the authors hypothesize that when white millennials are asked to think about tweets from black men in the self-reported data, they may perceive them as more knowledgeable about the topic. However, eye-tracking data indicated that, subconsciously, the participants still pay more attention to tweets from white men.

The researchers plan to look further into the issue. The current findings revealed several items of note for researchers and those trying to reach millennials. Namely, race and identity matter when it comes to Twitter, and that conscious and unconscious responses were different, suggesting self-reported data should always be viewed cautiously. Finally, the messenger can be just as important as the message.

"If you want a message to hit home with white millennials, you have to think not only about the message but who is delivering the message," Erba said. "There needs to be a 'match up' between the topic discussed and the perceived identity of the spokesperson."

With average precipitation of 35 inches per four-month season over an area encompassing most of the Indian subcontinent, the South Asia summer monsoon is intense, only partly understood, and notoriously difficult to predict. Until now, according to findings by Nir Y. Krakauer, a City College of New York civil engineer.

Because of the monsoon's enormous impact on these sectors, his research is of importance to a range of activities, including agriculture, industry, fishing and hydropower.

A frequent visitor to the region, stretching from Nepal to Sri Lanka, Krakauer has devised a methodology that allows forecasts potentially up to a year in advance. Currently, most predictions are made about two months in advance of the South Asia monsoon season that runs from June to September, but it is not known how far ahead skillful forecasts might be possible.

"People usually use one or two predictors for forecasts," said the Grove School of Engineering associate professor who is also affiliated with the CCNY-based NOAA-CREST. "Many of these predictors are one or another pattern of sea surface temperatures. My question was how do you find which patterns are important for forecasting the monsoon - the amount of rain and where it will be?"

Unlike other forecasters who use only the sea surface temperature readings from neighboring waters, Krakauer looked at the predictive potential of all the common patterns in the sea surface temperature map. He developed prediction methods using global sea surface temperature and monsoon precipitation data from between 1901 to 1996, and tested the performance of his prediction methods on data from 1997-2017.

"What I found is that two methods seem to do a good job of forecasting the monsoon. I looked at the sea surface temperatures at the beginning of the monsoon, and going back as far as four years before."

His finding was that, generally, the closer to the beginning of the monsoon season, the more accurate forecasts that are based on sea surface temperature can be. But predictions with some accuracy can be made as far as a year in advance.

Getting a better sense of how much water will be available is particularly important given that the rainfall is getting more intense in South Asia while the total amount remains constant, meaning that more rain is falling in a shorter period. This could be problematic for farmers in the region.

Entitled "Year-ahead predictability of South Asian Summer Monsoon Precipitation," Krakauer's research appears in the journal Environmental Research Letters.

His work in South Asia has been partly supported by USAID, most recently as part of the US-Pakistan Center for Advanced Studies on Water program.

A well-known, four-year study found popular arthritis drug Celebrex no more dangerous for the heart than older drugs in its same classification - commonly called NSAIDs. Now, a big-data analysis of patient records at Vanderbilt University has found a link specifically between Celebrex and heart valve calcification.

W. David Merryman, professor of biomedical engineering, and Ph.D. student Megan Bowler started out by testing celecoxib, the active compound in Celebrex, on valve cells in an effort to see if it could double as an aortic stenosis therapy. It made the problem worse.

To confirm their theory about a link between celecoxib and valve calcification, Merryman, who is also a professor of pharmacology, medicine and pediatrics at Vanderbilt, recruited Michael Raddatz, an M.D./Ph.D. student, to analyze more than 8,600 relevant, anonymous patient records from Vanderbilt University Medical Center. Raddatz checked whether there was a link between Celebrex use and aortic valve disease, and, after correcting for other risk factors, discovered that patients who had taken Celebrex had a 20 percent increased prevalence of valve disease.

The team's results appear today, which is National Heart Valve Disease Awareness Day, in the Journal of the American College of Cardiology (JACC): Basic to Translational Science.

The 2016 New England Journal of Medicine study that found Celebrex no more damaging than naproxen and ibuprofen only looked at cardiovascular death and nonfatal heart attack or stroke, not valve disease, which affects more than a quarter of the U.S. population older than 65.

"In this study, we're adding a long-term perspective on celecoxib use," said Bowler, who recently earned her Ph.D. "Calcification in the aortic valve can take many years. So if you're at a higher risk for it, you might want to consider taking a different painkiller or rheumatoid arthritis treatment."

As part of the same study, Bowler and Merryman found dimethyl celecoxib - an inactive form of celecoxib - could potentially slow or stop aortic stenosis. Merryman said he intends to keep testing dimethyl celecoxib for its beneficial effects on heart valve health.

Researchers have engineered "antibody-like" T cell receptors that can specifically stick to cells infected with cytomegalovirus, or CMV, a virus that causes lifelong infection in more than half of all adults by age 40. These receptors represent a new potential treatment option, could aid the development of CMV vaccines and might also be used to target brain tumors.

In the healthy immune system, CMV lies dormant as T cells circulate through the body and detect infected cells. While antibodies recognize only proteins on the surface of cells, T cells use their membrane-bound T cell receptors, or TCRs, to detect disease-associated proteins hiding inside the cellular membrane. TCRs can then tell T cells to destroy the infected cell, which is normally the case with CMV. However, for immunocompromised patients, this defensive mechanism is greatly diminished and the virus can become life-threatening.

Researchers have used T cells to treat disease before, but engineering and transplanting whole T cells is both costly and invasive. In a new study published in the Journal of Biological Chemistry, a team of engineers took an alternative approach, producing CMV-detecting TCRs that, like antibodies, float freely through the body and bind tightly to their diseased targets.

"Right now we've got a molecule that looks like an antibody but it binds to a (CMV-associated) peptide that would normally be recognized by a TCR," said Jennifer Maynard, a professor of chemical engineering at the University of Texas at Austin and senior author of the study. "Antibodies cannot normally access these molecules so that's a big deal."

To produce therapeutic biomolecules, researchers often use bacterial or yeast cells as miniature factories. However, those cell types have had minimal success in generating stable human TCRs. Because the receptors evolved in mammalian cells, the molecular machinery of foreign cell types often introduces defects, Maynard said. To provide the TCRs a more suitable environment, the authors used Chinese hamster ovary cells.

"These proteins are really difficult to work with, so we thought we'll just keep them in the environment where they're happy, and they're happy on the surface of a mammalian cell," Maynard said.

TCRs naturally create loose bonds with their targets but the authors wanted theirs to bind and not let go. To strengthen these connections, the authors randomly mutated the DNA of the TCR component that detects the CMV peptide. They then inserted many versions of the mutated DNA into hamster cells, which then manufactured about a million different types of TCR, Maynard said.

The researchers then measured which mutated version established the strongest bond by exposing the myriad TCR variations expressed on the surface of the hamster cells to the CMV peptide.

"We found one that was our favorite," Maynard said. "We improved the binding affinity 50-fold."

Then the challenge was to liberate the TCRs from the T cell membrane. To achieve this, the researchers further edited the DNA so that the TCRs would attach to the protein that composes the stem of "Y"-shaped antibodies. And to help these proteins hold their shape, they added a bond inside the TCR and also prevented any sugars from attaching. Altogether, these changes seemed to do the trick, Maynard said.

These "antibody-like" TCRs could be used to track disease progression in patients or to evaluate how well developing vaccines are working. These TCRs might also restore some of the lost immune response in immunocompromised patients by instructing their cells to attack CMV infections, Maynard said.

Another big opportunity for this new molecule is to treat glioblastoma. Although the brain tumors do not produce many distinct markers, they do suppress the immune system, which in CMV-infected patients can bring the virus back to life within the cancer cells, Maynard said.

"Our protein could be used to specifically target glioblastoma cells, and it would provide a very unique marker," Maynard said. "We would use this to monitor or kill some of those tumor cells."

SALINAS, CALIFORNIA--Planting small seeds simply: The allure of the slide hammer seeder

The development of a simply made and easy-to-use planting device could make growing important herbs and beneficial insect-attracting plants significantly more efficient and effective. The low-cost tool, known as the Slide Hammer Seeder (a jab-style seeder), gives farmers and gardeners specific control in sowing plants with very small seeds.

The use and assembly of this device is documented by Eric Brennan of the USDA's Agricultural Research Service in his article "The Slide Hammer Seeder: A Novel Tool for Planting Small Seeds", an open-access article published in HortTechnology.

Planting seeds by hand has been standard operating procedure since the beginning of agriculture more than 10,000 years ago. Even in the modern era, hand seeding is still important for major staple crops, especially in many parts of the developing world. Although jab-style seeders were widely used for corn in the United States during the early 1900s, their use today is primarily in research plots for agronomic crops with relatively large seeds.

However, these seeders are unsuitable for precision planting of small-seeded species that are of interest as cash crops or as "insectary plants"--those grown in high-value vegetable crops to provide pollen and nectar for beneficial insects.

To address the need for a seeder that allows the precise planting of small-seeded plants, the slide hammer seeder was developed. To make one, all the parts are available at your local hardware store at a cost of about US$32.50, and assembly can take as little as 2 hours.

Using the slide hammer seeder, seed is discharged in small quantities beneath the soil at preset depths, calculated for optimum growth potential.

Brennan adds, "I think this planter can really help farmers to accurately inter-seed important insectary plants like sweet alyssum between vegetable crops to help control aphids without pesticides. It also could be great for precise seeding of novel and nutritious vegetables such as purslane, which has very small and expensive seeds.

In the most comprehensive international comparison of its kind, a USC study found that the United States has the highest drug overdose death rates among a set of high-income countries.

Drug overdose mortality has reached unprecedented levels in the United States, more than tripling over the past two decades. But is this a uniquely American epidemic, or are other high-income counties facing a similar crisis?

"The United States is experiencing a drug overdose epidemic of unprecedented magnitude, not only judging by its own history but also compared to the experiences of other high-income countries," said study author Jessica Ho, assistant professor at USC Leonard Davis School of Gerontology. "For over a decade now, the United States has had the highest drug overdose mortality among its peer countries."

The study, published February 21 in Population and Development Review, found that drug overdose death rates in the United States are 3.5 times higher on average when compared to 17 other high-income counties. The study is the first to demonstrate that the drug overdose epidemic is contributing to the widening gap in life expectancy between the United States and other high-income countries.

Drug overdose deaths cut into American life expectancy

The study found that prior to the early 2000s, Finland and Sweden had the highest levels of drug overdose mortality. Drug overdose mortality in the United States is now more than 27 times higher than in Italy and Japan, which have the lowest drug overdose death rates, and double that of Finland and Sweden, the countries with the next highest death rates.

By 2013, drug overdose accounted for 12 percent and 8 percent of the average life expectancy gap for men and women, respectively, between the United States and other high-income countries. Without drug overdose deaths, the increase in this gap between 2003 and 2013 would have been smaller: one-fifth smaller for men and one-third smaller for women.

"The American epidemic has important consequences for international comparisons of life expectancy. While the United States is not alone in experiencing increases in drug overdose mortality, the magnitude of the differences in levels of drug overdose mortality is staggering," said Ho.

In 2003, life expectancy at birth would have been 0.28 years higher for American men and 0.17 years higher for American women in the absence of drug overdose deaths. Ten years later, these figures had increased to 0.45 years for American men and 0.30 years for women. In both 2003 and 2013, the United States lost the most years of life from drug overdose among high-income countries, with the difference increasing dramatically over that time period.

"On average, Americans are living 2.6 fewer years than people in other high-income countries. This puts the United States more than a decade behind the life expectancy levels achieved by other high-income countries. American drug overdose deaths are widening this already significant gap and causing us to fall even further behind our peer countries," Ho said.

A uniquely American phenomena - but will it stay that way?

Over 70,000 people died from drug overdoses in the United States in 2017, and the National Safety Council announced in January that Americans are now more likely to die of an accidental opioid overdose than in a car crash.

Potential drivers of the country's strikingly elevated drug overdose mortality levels include health care provision, financing and institutional structures, such as fee-for-service reimbursement systems and tying physician reimbursement to patient satisfaction. Additional factors include a well-documented marketing blitz by the manufacturers of Oxycontin, American cultural attitudes towards pain and the medical establishment, and the scarcity of substance abuse treatment in the United States, where only an estimated 10 percent of those with a substance abuse disorder receive treatment.

Despite its rapid ascent to the top of this tragic list, the United States may soon have competition for its dubious distinction. Ho points to the potential for drug overdose mortality to increase in other countries in the near future, noting similar and troubling patterns in Australia, Canada and the United Kingdom.

While opioids became a cornerstone of pain treatment in the late 1990s and early 2000s in the United States, other countries either didn't use strong opioids for pain relief or placed greater restrictions on their use. Exceptions include Australia, which experienced a switch from weak to strong opioids that is reflected in its 14-fold increase in oxycodone consumption between 1997 and 2008, and Ontario, Canada, which saw an 850 percent increase in oxycodone prescriptions between 1991 and 2007. Both countries also experienced large increases in drug overdose mortality.

Although the current American epidemic started with prescription opioids, it is now rapidly transitioning to heroin and fentanyl. European countries may be on the opposite trajectory, which could nonetheless result in more drug overdose deaths over time. "The use of prescription opioids and synthetic drugs like fentanyl are becoming increasingly common in many high-income countries and constitute a common challenge to be confronted by these countries," Ho said.

The USC study utilized data on cause of death from the Human Mortality Database and the World Health Organization Mortality Database for the set of 18 countries, along with additional data from vital statistics agencies in Canada and the United States to produce country-, year-, sex-, and age-specific drug overdose death rates between 1994 and 2015. Deaths from both legal and illegal drugs (not limited to opioids) and deaths of all intents were included.

With herbivores, omnivores, carnivores, insectivores, frugivores, scavengers and decomposers, Earth's ecosystems function within a vast web of interactions among plants, animals, insects, fungi and microorganisms.

A fundamental part of this web resides in the equilibrium of the food chain that links predators to herbivores and regulates plant production on our planet.

Equilibria between predators and plant-feeding prey may be disrupted by future climate change, according to a study published in Nature Climate Change.

"The study describes the causes of this disruption and shows it can be explained by the components of climate that will change in future, especially temperature," said Gustavo Quevedo Romero, a professor at the University of Campinas's Biology Institute (IB-UNICAMP) in São Paulo State, Brazil, and lead author of the article.

The study concluded that climate change can redistribute the strength of ecological interactions between predator and prey species. The results show that higher temperatures and a more stable climate with less seasonal variability lead to more intense predation pressure.

However, the increased climate instability that accompanies ongoing climate change, especially in tropical regions, will lead to an overall decline in predation pressure in the tropics. In contrast, predation pressure will rise in some temperate regions.

"This reorganization of the forces of species interactions could have disastrous consequences for terrestrial ecosystems and for the ecosystem services they provide, such as biological control and nutrient cycling," Romero said.

For example, many organic farmers in the tropics depend on biological control by natural enemies of crop pests, and projected changes in climate may weaken the effectiveness of predators in controlling these pests.

Romero's coauthors are Thadeu Sobral-Souza, a biologist at São Paulo State University's Bioscience Institute (IB-UNESP), and ecologists Tomas Roslin at the Swedish University of Agricultural Sciences in Uppsala and the University of Helsinki in Finland, Thiago Gonçalves-Souza at the Rural Federal University of Pernambuco, Nicholas Marino at the Federal University of Rio de Janeiro, Pavel Kratina at Queen Mary University of London in the United Kingdom, and William Petry at ETH Zurich in Switzerland.

The study was supported by São Paulo Research Foundation - FAPESP
and by the Brazilian government via the National Council for Scientific and Technological Development (CNPq) and the Brazilian Innovation Agency (FINEP).

The new study was based on data collected for a previous study, published in 2017 in the journal Science
and led by Roslin.

In the previous study, researchers measured bites or other feeding marks on artificial caterpillars to show that the higher an ecosystem's latitude (from the equator to temperate and polar regions), the lower the probability of herbivore predation.

The researchers measured predation risk for 2,879 model caterpillars made of green plasticine and monitored at 31 sites around the world along a latitudinal gradient from 30.4° south (a parallel spanning Rio Grande do Sul in southern Brazil, South Africa, and Central Australia) to 74.3° north (spanning the Canadian Arctic, Greenland and the far north of Siberia). The elevation gradient for the 31 sites ranged from 0 (Denmark) to 2,100 m above sea level (Ecuador). In comparison, it is worth noting that Mexico City is 2,240 m above sea level.

The plasticine caterpillars were glued to the upper side of undamaged leaves of plants with at most a height of one meter. Based on their analysis of predator attack marks made by teeth, beaks, radulae or mandibles and preserved in the modeling clay, the researchers identified attacks by six predator groups: birds, lizards, mammals, arthropods and gastropods (snails or slugs).

Climate adjustment

In the Science article, the authors confirmed the hypothesis that biotic interaction strength increases toward the equator and decreases toward the poles. In the study now published in Nature Climate Change, they compared the caterpillar predation and location data with present and future bioclimatic data based on several climate models that predict climate change from carbon dioxide emissions.

"All the existing research on the role of global climate change with respect to biotic interactions has been theoretical, as far as I know. Our study is the first to investigate the link between biotic interactions and climate change at a global scale on the basis of empirical data," Romero said.

"Furthermore, it's the first time anyone has used niche modeling to study biotic interactions, as this method was developed to predict species distributions."

For the new study, the authors extracted a set of bioclimatic variables from WorldClim 2, a database of 19 bioclimatic variables applied globally to a 1 km² resolution grid.

Next, they used the structural equation modeling method to determine the relative significance of the direct and indirect effects of absolute latitude, elevation and the underlying local climate (including precipitation and temperature) on predation pressure.

According to Romero, the models showed that the predation data were best explained by temperature variations.

Future projections

The researchers were able to predict the redistribution of predation pressure at a global scale for a 2070 climate scenario. "Generally, we found that by 2070, predation pressure may be significantly affected by temperature changes but may not be affected by precipitation changes," Romero said.

Predation pressure will be affected both by the increase in temperature forecasted for 2070 and by temperature variability, that is, the phenomenon of sharp increases and decreases in temperature in certain ecosystems.

"Temperature instability rather than warmer temperatures will reduce predation pressure," he said. "This impact will be exacerbated in tropical regions, where the climate is projected to become more unstable."

The findings suggest that as temperatures rise, predation pressure will intensify moderately in temperate regions ranging from North America to Asia. In Scandinavia, the increase in predation pressure will be greatest among arthropods.

Predation pressure will decrease in equatorial regions, where the most biodiverse ecosystems are located, including equatorial Africa, Southeast Asia, tropical South America, Central America, and the Caribbean.

Brazil and Colombia will be particularly affected. Brazil may be the most affected country of all owing to its position in the tropics and the vastness of the Amazon rainforest.

"The most important consequence is simple. If the current climate affects current predation pressure, then we can expect climate change to lead to a change in predation pressure. Climate change is reflected by not only changes in species distributions but also changes in the interactions among species," Romero said.

"A decrease in predation pressure in the tropics could affect tropical crop yields, and in turn, this affect would increase risks to food security owing to a reduction in the efficiency of biological control in areas that are already more vulnerable due to climate change."

CAMBRIDGE, Mass. -- Today's data centers eat up and waste a good amount of energy responding to user requests as fast as possible, with only a few microseconds delay. A new system by MIT researchers improves the efficiency of high-speed operations by better assigning time-sensitive data processing across central processing unit (CPU) cores and ensuring hardware runs productively.

Data centers operate as distributed networks, with numerous web and mobile applications implemented on a single server. When users send requests to an app, bits of stored data are pulled from hundreds or thousands of services across as many servers. Before sending a response, the app must wait for the slowest service to process the data. This lag time is known as tail latency.

Current methods to reduce tail latencies leave tons of CPU cores in a server open to quickly handle incoming requests. But this means that cores sit idly for much of the time, while servers continue using energy just to stay powered on. Data centers can contain hundreds of thousands of servers, so even small improvements in each server's efficiency can save millions of dollars.

Alternatively, some systems reallocate cores across apps based on workload. But this occurs over milliseconds -- around one-thousandth the desired speed for today's fast-paced requests. Waiting too long can also degrade an app's performance, because any information that's not processed before an allotted time doesn't get sent to the user.

In a paper being presented at the USENIX Networked Systems Design and Implementation conference next week, the researchers developed a faster core-allocating system, called Shenango, that reduces tail latencies, while achieving high efficiencies. First, a novel algorithm detects which apps are struggling to process data. Then, a software component allocates idle cores to handle the app's workload.

"In data centers, there's a tradeoff between efficiency and latency, and you really need to reallocate cores at much finer granularity than every millisecond," says first author Amy Ousterhout, a PhD student in the Computer Science and Artificial Intelligence Laboratory (CSAIL). Shenango lets servers "manage operations that occur at really short time scales and do so efficiently."

Energy and cost savings will vary by data center, depending on size and workloads. But the overall aim is to improve data center CPU utilization, so that every core is put to good use. The best CPU utilization rates today sit at about 60 percent, but the researchers say their system could potentially boost that figure to 100 percent.

"Data center utilization today is quite low," says co-author Adam Belay, an assistant professor of electrical engineering and computer science and a CSAIL researcher. "This is a very serious problem [that can't] be solved in a single place in the data center. But this system is one critical piece in driving utilization up higher."

Joining Ousterhout and Belay on the paper are Hari Balakrishnan, the Fujitsu Chair Professor in the Department of Electrical Engineering and Computer Science, and CSAIL PhD students Jonathan Behrens and Joshua Fried.

Efficient congestion-detection

In a real-world data center, Shenango -- algorithm and software -- would run on each server in a data center. All the servers would be able to communicate with each other.

The system's first innovation is a novel congestion-detection algorithm. Every five microseconds the algorithm checks data packets queued for processing for each app. If a packet is still waiting from the last observation, the algorithm notes there's at least a 5-microsecond delay. It also checks if any computation processes, called threads, are waiting to be executed. If so, the system considers that a "congested" app.

It seems simple enough. But the queue's structure is important to achieving microsecond-scale congestion detection. Traditional thinking meant having the software check the timestamp of each queued-up data packet, which would take too much time.

The researchers implement the queues in efficient structures known as "ring buffers." These structures can be visualized as different slots around a ring. The first inputted data packet goes into a starting slot. As new data arrive, they're dropped into subsequent slots around the ring. Usually, these structures are used for first-in-first-out data processing, pulling data from the starting slot and working toward the ending slot.

The researchers' system, however, only stores data packets briefly in the structures, until an app can process them. In the meantime, the stored packets can be used for congestion checks. The algorithm need only compare two points in the queue -- the location of the first packet and where the last packet was five microseconds ago -- to determine if packets are encountering a delay.

"You can look at these two points, and track their progress every five microseconds, to see how much data has been processed," Fried says. Because the structures are simple, "you only have to do this once per core. If you're looking at 24 cores, you do 24 checks in five microseconds, which scales nicely."

Smart allocation

The second innovation is called the IOKernel, the central software hub that steers data packets to appropriate apps. The IOKernel also uses the congestion detection algorithm to quickly allocate cores to congested apps orders of magnitude more quickly than traditional approaches.

For instance, the IOKernel may see an incoming data packet for a certain app that requires microsecond processing speeds. If the app is congested due to a lack of cores, the IOKernel immediately devotes an idle core to the app. If it also sees another app running cores with less time-sensitive data, it will grab some of those cores and reallocate them to the congested app. The apps themselves also help out: If an app isn't processing data, it alerts the IOKernel that its cores can be reallocated. Processed data goes back to the IOKernel to send the response.

"The IOKernel is concentrating on which apps need cores that don't have them," Behrens says. "It's trying to figure out who's overloaded and needs more cores, and gives them cores as quickly as possible, so they don't fall behind and have huge latencies."

The tight communication between the IOKernel, algorithm, apps, and server hardware is "unique in data centers" and allows Shenango to function seamlessly, Belay says: "The system has global visibility into what's happening in each server. It sees the hardware providing the packets, what's running where in each core, and how busy each of the apps are. And it does that at the microsecond scale."

Next, the researchers are refining Shenango for real-world data center implementation. To do so, they're ensuring the software can handle a very high data throughput and has appropriate security features.

Bottom Line: An analysis of cervical precancers over a period of seven years showed that two strains of human papillomavirus (HPV) that have been targeted by vaccination since 2006 have declined, accounting for a smaller proportion of cervical disease. The study offers evidence that HPV vaccination reduced the incidence of infections that can lead to cervical cancer

Journal in Which the Study was Published: Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

Author: Nancy McClung, PhD, RN, epidemic intelligence service officer at the Centers for Disease Control and Prevention (CDC) in Atlanta.

Background: "Almost all sexually active individuals will get HPV at some point in their lifetime, but most HPV infections go away on their own without any treatment," McClung explained. "If an HPV infection does not go away, it can cause cell changes that, over time, develop into a lesion on the cervix called a cervical precancer. Cervical precancers allow us to observe the impact of HPV vaccination earlier than cervical cancer, which can take decades to develop."

Previous research has suggested that the incidence of cervical precancer has been decreasing. In this study, researchers sought to determine whether HPV types 16 and 18, which are responsible for approximately 70 percent of cervical cancers worldwide, are also decreasing. These two types have been targeted by the quadrivalent HPV vaccine, which was most typically administered in the United States between 2006 and 2015, and by the 9-valent vaccine that is the only vaccine currently administered in the United States.

How the Study Was Conducted: As part of the CDC's Human Papillomavirus (HPV) Vaccine Impact Monitoring Project (HPV-IMPACT), McClung and colleagues analyzed more than 10,000 archived specimens collected between 2008 and 2014 from women aged 18-39 who had been diagnosed with grade 2 or 3 cervical intraepithelial neoplasia or adenocarcinoma in situ (CIN2+). Both are precancerous conditions that can arise from persistent HPV infection and can lead to cervical cancer. Researchers tested the samples for 37 HPV types, then analyzed the proportion and estimated number of cases by HPV types over time.

Results: The researchers found that the number of cases of CIN2+ reported to HPV-IMPACT declined 21 percent, from 2,344 in 2008 to 1,857 in 2014. The estimated number of cases attributed to HPV16/18 declined from 1,235 in 2008 to 819 cases in 2014.

Among women who were vaccinated, the proportion of CIN2+ cases that were HPV 16/18-positive declined from 55.2 percent to 33.3 percent. Among unvaccinated women, the proportion of CIN2+ cases that were HPV 16/18-positive declined from 51.0 percent to 47.3 percent, and among those with unknown vaccination status, from 53.7 percent to 45.8 percent.

Author's Comments: McClung explained that some vaccinated women were most likely HPV 16/18-positive because they were infected with these HPV types before they were vaccinated. The majority of vaccinated women in this study received the vaccine in their early 20s, after the age most women initiate sexual activity.

McClung said the decline in unvaccinated women may be due to "herd protection," which occurs when a significant proportion of a population has developed immunity to an infectious disease, making its spread less likely. Herd protection can be conferred through vaccination or immunity built up from prior infection, she explained.

Researchers noted that every age group saw significant declines in the proportion of CIN2+ cases that were HPV 16/18-positive, with the exception of the oldest group, those aged 35-39. McClung said this finding reflects the fact that most of these women were not eligible for vaccination because of their age.

Furthermore, while non-Hispanic whites and blacks saw declines in the proportion of HPV 16/18-positive precancers, Hispanic and Asian women did not. McClung said that the Hispanic and Asian women included in this study may have been less likely to be vaccinated. However, as of 2016, HPV vaccine uptake was robust in Hispanic and Asian teens; therefore, racial and ethnic disparities are expected to diminish, McClung said.

The CDC's most recent statistics show that 49.5 of girls and 37.5 percent of boys aged 13-17 are up-to-date on all recommended doses of the HPV vaccine. McClung said clinicians should continue to strongly recommend the HPV vaccine for all preteens at age 11 or 12, and effectively answer parents' common questions about the vaccine.

Overall, McClung said, the study indicated that efforts to encourage families to get the HPV vaccination for their teens are paying off and should be continued.

"This is clear evidence that the HPV vaccine is working to prevent cervical disease in young women in the United States," McClung said. "In the coming years, we should see even greater impact as more women are vaccinated during early adolescence and before exposure to HPV."

MORGANTOWN, W.Va.--How is a healthy retina cell like a tumor cell? It hijacks an energy-producing chemical reaction to churn out molecular building blocks. When tumor cells do it, they use the building blocks to make cancer grow and spread. But when retina cells do it, they renew photoreceptor membranes that keep our vision sharp.

West Virginia University researcher Jianhai Du is parsing how the retina accomplishes this feat. His findings are published in the latest edition of the Proceedings of the National Academy of Sciences.

"We eat glucose and use it as a major energy source," said Du, an assistant professor in the School of Medicine's Department of Biochemistry and Department of Ophthalmology and Visual Sciences. Through a multistep chemical process, almost all of the healthy cells in our body fixate on turning this glucose into fuel that mitochondria--essentially, the cells' boiler rooms--can burn for energy. Less than 20 percent of the glucose is used to make raw materials for new cells.

"But in tumor cells, it's almost the opposite," Du said. Tumor cells go out of their way to thwart the chemical reactions that would normally transform glucose into energy. Instead, they turn most of the glucose into cancer's basic components.

"It's like they're building different houses. When you're building houses, you need basic materials like wood and concrete. When cancers grow, they need membranes, lipids, nucleotides."

Retina cells use glucose similarly, only rather than using it to sustain and spread cancer, they use it to generate new photoreceptor outer segments that replace the old, damaged ones.

Du and his research team suspected that a specific protein, called mitochondrial pyruvate carrier 1, played a role in the retina's ability to scrap glucose for photoreceptor parts. MPC1 is crucial to getting a derivative of glucose--called pyruvate--into the cells' "boiler rooms," where it can be burned to power the cell. "But in almost all cancer cells, MPC1 is decreased because the cells do not want to move pyruvate into mitochondria," Du explained.

The scientists used animal models to study if--and how--MPC1 and retinal health were linked. They also tested whether or not the scant amount of pyruvate that does go into the retina's mitochondria is important.

The team removed all of the MPC1 from some of their animal models. In the rest of the models, they left intact. "It turns out, the small amount of glucose that is being used in the mitochondria is critical for mitochondrial function, photoreceptor function and viability," said Du.

The researchers observed that MPC1-deficient models had dramatically impaired vision. Compared to their counterparts with typical MPC1 expression, their photoreceptors functioned less than half as well, at all intensities of light.

The team also found that MPC1 depletion caused retinal degeneration. In addition, it damaged the structure of the retina's mitochondria in "very, very unique ways," Du said.

"One important factor in developing age-related macular degeneration is mitochondria not functioning very well. But people don't know exactly what causes it, and there is still no treatment," he said. Du's research may provide insight into how this poorly understood disease manifests in patients and how doctors can treat it. He and his colleagues are conducting experiments to determine whether fat can be used as an alternative fuel source for retinal mitochondria that can't use glucose properly.

Du also plans to study what happens when MPC1 is blocked on a cell-specific basis. "In this project, we blocked the whole retina. But in the next one, we want to block photoreceptors or glial cells to see how small molecules cross between them. We want to address cell-cell interactions." Such a project could have an impact beyond the diagnosis and treatment of eye diseases. It could even deepen neuroscientists' understanding of how brain cells interact.

It's been said that variety is the spice of life, and now scientists say variety in your social circle may help you live longer. Researchers at The University of Texas at Austin have found that older adults who spend more time interacting with a wide range of people were more likely to be physically active and had greater emotional well-being.

In a paper out Feb. 20 in the Journals of Gerontology Series B: Psychological Sciences and Social Sciences, researchers found that study participants who interacted more with family members and close friends, as well as acquaintances, casual friends, service providers and strangers were more likely to have higher levels of physical activity, less time spent sitting or lying around, greater positive moods and fewer negative feelings. It is the first study to link social engagement with physical activity throughout the day.

"Adults often grow less physically active and more sedentary as they age, and these behaviors pose a risk factor for disease and death," said Karen Fingerman, a professor of human development and family sciences at UT Austin and the director of the university's new Texas Aging & Longevity Center. "It is difficult to convince people to go to the gym or commit to work out on a regular basis. But they may be willing to reach out to acquaintances, attend an organized group event, or talk to the barrista who serves them at their favorite coffee shop. Socializing in these contexts also can increase physical activity and diverse behaviors in ways that benefit health without necessarily working up a sweat."

The researchers asked study participants about their activities and social encounters every three hours for about a week. Participants also wore electronic devices to monitor their physical activity. Fingerman and the team observed that during the three-hour periods when participants were engaging with a greater variety of social partners, they reported engaging in a greater variety of activities such as leaving the house, walking, talking with others, or shopping. They also engaged in more objectively measured physical activity, and less time being sedentary.

Previous studies have shown that close social ties, like family and close friends, can be beneficial to older adults by providing a buffer against stress and improving emotional well-being. Researchers had not examined physical activity or the benefits of more peripheral social ties.

This study showed those acquaintances or peripheral ties may encourage older adults to be more physically active, a key factor that has been shown to contribute to physical and emotional health, as well as cognitive ability.

"Older adults may be able to be more sedentary with their close friends and family -- sitting and watching TV or otherwise lounging at home," Fingerman said. "But to engage with acquaintances, older adults must leave the house, or at least get up out of their chair to answer the door."

The study included more than 300 adults over 65 years old who lived in the Austin metro area and controlled for factors such as age, race, gender, marital status, education and ethnicity.

"Prior research on aging has focused almost entirely on the benefits of social connection with close social ties such as a spouse or an adult child," said co-author Debra Umberson, sociology professor and director of UT Austin's Population Research Center. "This new research relies on truly novel data that capture both the amount and quality of contact with all types of people that the elderly encounter throughout the day -- and the results show us that these routine encounters have important benefits for activity levels and psychological well-being. This new information suggests the importance of policies and programs that support and promote routine and informal social participation."