It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, April 28, 2021
Study finds people of color more likely to participate in cancer clinical trials
Findings counter belief that minorities are less like to participate in health research
People of color, those with a higher income and younger individuals are more likely to participate in clinical trials during their cancer treatment according to a new study from the University of Missouri School of Medicine.
Clinical trials are research studies that involve people who volunteer to take part in tests of new drugs, current approved drugs for a new purpose or medical devices.
The study analyzed data collected from the Centers for Disease Control and Prevention (CDC) Behavioral Risk Factor Surveillance System Survey, which is an annual national telephone survey designed to collect health-related data from U.S. adults. Survey years selected included the question, "Did you participate in a clinical trial as part of your cancer treatment?" The analysis of 20,053 respondents revealed an average overall clinical trial participation rate of 6.51%. Among 17,600 white respondents, participation was 6.24%; among 445 Hispanic respondents, participation was 11%; and among 943 Black respondents, participation was 8.27%.
"This study informs our understanding of who is participating in cancer clinical trials," said Lincoln Sheets, MD, PhD, assistant research professor at the MU School of Medicine. "We found people of color were more likely to participate in cancer clinical trials than white cancer patients when controlling for other demographic factors. It could be that in previous studies, the effects of income, sex or age were muddling the true picture."
Sheets said the analysis also indicated people who earn more than the national median household income of $50,000 annually and the young were more likely to participate in clinical trials during cancer treatment.
"Taken in total, the results of this study help confirm that there are sociodemographic disparities in cancer clinical trials, indicating there are deficiencies in the system as it stands now," Sheets said. "We must lessen financial barriers to participation, improve logistical accessibility of cancer clinical trials and loosen restrictions on the enrollment of patients with comorbidities."
Sheets said improving access to transportation, childcare and health insurance would remove some of the structural and logistical barriers that prevent people from participating in cancer clinical trials.
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Sheets collaborated on the study with MU School of Medicine student Shelby Meyer.
Their study, "Sociodemographic diversity in cancer clinical trials: New findings on the effect of race and ethnicity," was published by the journal Contemporary Clinical Trials Communications. The authors of the study declare that they have no conflicts of interest.
NEWS RELEASE
El Niño can help predict cacao harvests up to 2 years in advance
Long-term weather data is absent in many places, complicating rain predictions for crops. Researchers found that the El Niño climate cycle can be a reliable substitute for weather data
THE ALLIANCE OF BIOVERSITY INTERNATIONAL AND THE INTERNATIONAL CENTER FOR TROPICAL AGRICULTURE
IMAGE: A WOMAN INSPECTS HARVESTED CACAO BEANS DRYING IN THE SUN IN SOPPENG, SOUTH SULAWESI, INDONESIA. view more
CREDIT: COCOA CARE AND T. OBERTHU?R
When seasonal rains arrive late in Indonesia, farmers often take it as a sign that it is not worth investing in fertilizer for their crops. Sometimes they opt out of planting annual crops altogether. Generally, they're making the right decision, as a late start to the rainy season is usually associated with the state of El Niño Southern Oscillation (ENSO) and low rainfall in the coming months.
New research published in the Nature journal Scientific Reports shows that ENSO, the weather-shaping cycle of warming and cooling of the Pacific Ocean along the Equator, is a strong predictor of cacao harvests up to two years before a harvest.
This is potentially very good news for smallholder farmers, scientists, and the global chocolate industry. The ability to predict harvest sizes well in advance could shape on-farm investment decisions, improve tropical crop research programs, and reduce risk and uncertainty in the chocolate industry.
Researchers say that the same methods - which pair advanced machine learning with rigorous, short-term data collection on farmer practices and yields - can apply to other rain-dependent crops including coffee and olives.
"The key innovation in this research is that you can effectively substitute weather data with ENSO data," said Thomas Oberthür, a co-author and business developer at the African Plant Nutrition Institute (APNI) in Morocco. "Any crop that shares a production relationship with ENSO can be explored using this method."
About 80 percent of global cropland depends on direct rainfall (as opposed to irrigation), accounting for almost 60 percent of production. But rainfall data is sparse and highly variable in many of these regions, making it difficult for scientists, policymakers and farmers groups to adapt to the vagaries of the weather.
No weather data? No problem
For the study, researchers used a type of machine learning that did not require weather records for the Indonesian cacao farms that participated in the research.
Rather, they relied on data on fertilizer application, yields and farm type, which they plugged into a Bayesian Neural Network (BNN) and found that ENSO phases predicted 75 % of the variation in yields.
In other words, the sea-surface temperature of the Pacific accurately predicted cacao harvests in a large majority of cases for the farms in the study. In some cases, accurate predictions were possible 25 months before the harvest.
For the uninitiated, a model that can accurately predict 50% of yield variation is usually cause to celebrate. And such long-range predictive accuracy for crop yields crops is rare.
"What this allows us to do is superimpose different management practices - such as fertilization regimes - on farms and deduce, with a high level of confidence, those interventions that work," said James Cock, a co-author and emeritus researcher at the Alliance of Bioversity International and CIAT. "This is a whole paradigm shift toward operational research."
Cock, a plant physiologist, said that while randomized control trials (RCTs) are generally considered the gold standard in research, these are extremely costly and consequently often impossible to perform in developing tropical agricultural areas. The approach used here is much lower cost, requires no expensive collection of weather records and provides useful guidelines on how to better manage crops under variable weather.
Ross Chapman, a data analyst and the study's lead author, explained some of the key benefits of machine learning methods over conventional data analysis approaches:
"The BNN modeling differs from standard regression modeling because the algorithm takes input variables, such as sea-surface temperature and farm type, and then automatically 'learns' to recognize responses in other variables, such as crop yield," Chapman said. "The learning process uses the same fundamental process that the human mind learns to recognize objects and patterns from real-life experience. In contrast, standard models require manual supervision of different variables via human-generated equations."
The value of shared data
While machine learning may promise better crop yield predictions in the absence of weather data, scientists - or farmers themselves - still need to accurately collect certain production information and have that data readily available if machine-learning models are going to work.
In the case of the Indonesian cacao farms in the study, farmers had been part of a major chocolate company's training program on best practices. They kept track of inputs such as fertilizer application, freely shared that data for analysis, and an organization with a local presence, the International Plant Nutrition Institute (IPNI), kept tidy records for researchers to use.
In addition, scientists had previously divided their farms into ten similar groups, where topography and soil conditions were similar. The researchers used data on harvests, fertilizer applications and yields from 2013 to 2018 to build their model.
The knowledge gained by cacao growers gives them confidence on how and when to invest in fertilizers. The agronomic skills this vulnerable group acquired shields them against a loss in their investment, which typically occurs when weather is adverse.
Thanks to their collaboration with the researchers, now their knowledge can be, in a way, shared with growers of other crops in other regions of the world.
"This research could not have happened without dedicated farmers, IPNI and a strong farmers' support organization, Community Solutions International, to pull everyone together," Cock said, emphasizing the importance of multidisciplinary collaboration and balancing stakeholder's different needs.
"What scientists want is to know why something happens," he said. "Farmers want to know what works."
APNI's Oberthür said strong predictive modeling could benefit both farmers and researchers, and fuel further collaboration.
"You need to have tangible results if you're a farmer who is also collecting data, which is a lot of work," Oberthür said. "This modeling, which can provide farmers with beneficial information, may help incentivize data collection since farmers will see that they are contributing to something that provides benefits to them on their farms."
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About the Alliance
The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT) delivers research-based solutions that harness agricultural biodiversity and sustainably transform food systems to improve people's lives. Alliance solutions address the global crises of malnutrition, climate change, biodiversity loss, and environmental degradation.
The Alliance is part of CGIAR, a global research partnership for a food-secure future.
IMAGE: UC UNDERGRADUATE RESEARCH ASSISTANT JACOB HOSCHOUER TAKES SAMPLES FROM AN INACTIVE OIL WELL. view more
CREDIT: UC GEOLOGY
Uncapped, idle oil wells could be leaking millions of kilograms of methane each year into the atmosphere and surface water, according to a study by the University of Cincinnati.
Amy Townsend-Small, an associate professor of geology and geography in UC's College of Arts and Sciences, studied 37 wells on private property in the Permian Basin of Texas, the largest oil production region on Earth. She found that seven had methane emissions of as much as 132 grams per hour. The average rate was 6.2 grams per hour.
"Some of them were leaking a lot. Most of them were leaking a little or not at all, which is a pattern that we have seen across the oil and gas supply chain," Townsend-Small said. "A few sources are responsible for most of the leaks."
The study, published in the journal Environmental Research Letters, is the first of its kind on methane emissions from inactive oil wells in Texas.
"Nobody has ever gotten access to these wells in Texas," Townsend-Small said. "In my previous studies, the wells were all on public land."
A 2016 study by Townsend-Small found a similar issue in inactive wells she tested in Colorado, Wyoming, Ohio and Utah. Spread across the estimated 3.1 million abandoned wells, the leaking methane is equivalent to burning more than 16 million barrels of oil, according to government estimates.
Five of the inactive wells Townsend-Small studied in Texas were leaking a brine solution onto the ground, in some cases creating large ponds.
"I was horrified by that. I've never seen anything like that here in Ohio," Townsend-Small said. "One was gushing out so much water that people who lived there called it a lake, but it's toxic. It has dead trees all around it and smells like hydrogen sulfide."
Most of the wells had been inactive for three to five years, possibly because of fluctuations in market demand. Inactive wells could be a substantial source of methane emissions if they are not subject to leak detection and repair regulations, the UC study concluded.
The study was funded in part by a grant from the U.S. Department of the Interior.
Previous studies have found the basin generates 2.7 billion kilograms of methane per year or nearly 4% of the total gas extracted. That's 60% higher than the average methane emissions in oil and gas production regions nationally. This was attributed to high rates of venting and flaring due to a lack of natural gas pipelines and other gas production infrastructure.
Methane is a powerful greenhouse gas that scientists have linked to climate change. If the rate of methane leaks UC observed were consistent across all 102,000 idled wells in Texas, the 5.5 million kilograms of methane released would be equivalent to burning 150 million pounds of coal each year, according to an estimate by the magazine Grist and nonprofit news organization the Texas Observer.
Townsend-Small and her UC undergraduate research assistant Jacob Hoschouer, a study co-author, came to Texas at the suggestion of the media organizations, which wanted to explore the environmental impact of oil wells, particularly those that are inactive or abandoned. An expert on methane emissions, Townsend-Small has studied releases from oil and natural gas wells across the country.
The journalists arranged with the property owners for Townsend-Small to examine the wells.
President Joe Biden's administration has pledged $16 billion in its infrastructure plan to cap abandoned oil and gas wells and mitigate abandoned mines. Hoschouer said it would be gratifying if their research could help regulators prioritize wells for capping.
In the meantime, regular inspections of inactive wells using infrared cameras to identify leaks could address the problem, the UC study suggested.
CAPTION
UC associate professor Amy Townsend-Small stands in front of ponding water from an inactive oil well.
CREDIT
UC Geology
Reducing blue light with a new type of LED that won't keep you up all night
IMAGE: THIS PROTOTYPE DEVICE CREATES A WARM WHITE LIGHT WITHOUT THE BLUE HUES THAT CAN CAUSE HEALTH PROBLEMS. view more
CREDIT: JAKOAH BRGOCH
To be more energy efficient, many people have replaced their incandescent lights with light-emitting diode (LED) bulbs. However, those currently on the market emit a lot of blue light, which has been linked to eye troubles and sleep disturbances. Now, researchers reporting in ACS Applied Materials & Interfaces have developed a prototype LED that reduces -- instead of masks -- the blue component, while also making colors appear just as they do in natural sunlight.
LED light bulbs are popular because of their low energy consumption, long lifespan and ability to turn on and off quickly. Inside the bulb, an LED chip converts electrical current into high-energy light, including invisible ultraviolet (UV), violet or blue wavelengths. A cap that is placed on the chip contains multiple phosphors -- solid luminescent compounds that convert high-energy light into lower-energy visible wavelengths. Each phosphor emits a different color, and these colors combine to produce a broad-spectrum white light. Commercial LED bulbs use blue LEDs and yellow-emitting phosphors, which appear as a cold, bright white light similar to daylight. Continual exposure to these blue-tinted lights has been linked to cataract formation, and turning them on in the evening can disrupt the production of sleep-inducing hormones, such as melatonin, triggering insomnia and fatigue. To create a warmer white LED bulb for nighttime use, previous researchers added red-emitting phosphors, but this only masked the blue hue without getting rid of it. So, Jakoah Brgoch and Shruti Hariyani wanted to develop a phosphor that, when used in a violet LED device, would result in a warm white light while avoiding the problematic wavelength range.
As a proof of concept, the researchers identified and synthesized a new luminescent crystalline phosphor containing europium ((Na1.92Eu0.04)MgPO4F). In thermal stability tests, the phosphor's emission color was consistent between room temperature and the higher operating temperature (301 F) of commercial LED-based lighting. In long-term moisture experiments, the compound showed no change in the color or intensity of light produced. To see how the material might work in a light bulb, the researchers fabricated a prototype device with a violet-light LED covered by a silicone cap containing their luminescent blue compound blended with red-emitting and green-emitting phosphors. It produced the desired bright warm white light while minimizing the intensity across blue wavelengths, unlike commercial LED light bulbs. The prototype's optical properties revealed the color of objects almost as well as natural sunlight, fulfilling the needs of indoor lighting, the researchers say, though they add that more work needs to be done before it is ready for everyday use.
The abstract that accompanies this paper is available here.
The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS' mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world's scientific knowledge. ACS' main offices are in Washington, D.C., and Columbus, Ohio.
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The science of picky shoppers
New research defines what it means to be a picky shopper -- and what it means for businesses
UNIVERSITY PARK, Pa. -- There are hard-to-please customers in almost every industry, with certain people being picky about which clothes, houses and even romantic partners they will consider.
A new series of studies has found that shopper pickiness can go beyond shopping for the "best" option. The researchers define what it means to be "picky" and also developed a scale for measuring shopper pickiness.
Margaret Meloy, department chair and professor of marketing at Penn State, said the findings could help companies devise the best strategies for satisfying their pickier customers.
"If a company knows they have a lot of picky customers, they may need to change the way they reward salespeople or dedicate specific salespeople to their pickiest customers, because picky shoppers have very narrow preferences and they see perceived flaws in products others wouldn't notice," Meloy said. "Alternatively, a company may allow picky shoppers to customize their products to satisfy their idiosyncratic preferences. It's not just about offering the best products, but offering the products that are best for the picky customers."
Meloy added that even the most robust promotional strategies, like offering a free gift with purchase, may fail with picky customers.
Previous research has found that about 40% of people have family or friends they would consider "picky," suggesting the trait is common. The researchers said it might be helpful for retailers to have a better understanding of what being "picky" means for their customer base, and what those customers may need from a product or shopping experience.
Meloy said that while pickiness affects a customer's shopping habits and therefore affects a company's business, there hasn't been much research done on defining pickiness or investigating how it influences a customer's behavior.
"In marketing, we call customers who want the absolute best version of a product 'maximizers,'" Meloy said. "But with picky customers, the best is more idiosyncratic. For them, it might not be about getting the best quality, but getting the precise version of a product they have in their head -- a shirt in a very precise shade of black, for example. We wanted to explore this a bit more."
For the paper -- recently published in the Journal of Consumer Psychology -- the researchers performed a series of studies to create a scale for measuring shopper pickiness and to identify the consequences of that pickiness on customer behavior.
The first series of studies focused on developing the scale. The researchers said they created a series of questions that would help uncover the psychological dimensions of pickiness while also avoiding using the word "picky," since the word tends to have negative connotations. Once the researchers were confident the scale accurately measured pickiness, they conducted additional studies to examine the possible consequences of pickiness.
The researchers found that people who scored higher on the picky shopper scale tend to have a small window of what they consider acceptable, which the researchers described as having a small latitude of acceptance and a wide latitude for rejection. These shoppers were more likely to reject a free gift when offered as a thank you for participating in a survey.
"This may seem irrational to some people who may not understand why a person would reject things that come at no cost," said Andong Cheng, an assistant professor of marketing at the University of Delaware who earned her doctorate at Penn State. "We speculate that it could be psychologically costly for picky shoppers to take free items that they don't like because possessing these items is a source of irritation for these individuals."
Additionally, the researchers found that picky people didn't change their opinions based on a product's popularity. When they were informed that their top choice of a product was less popular than other options, people who scored high on the picky scale weren't swayed by that information. They stuck with their original selection.
Meloy said the results support the theory that being picky is a general personality trait that isn't just present in one situation or area of a person's life.
"We looked at a range of contexts to see whether being picky in one domain meant you were likely to be picky in others," Meloy said. "Sure enough, individuals who were picky in one domain were picky in other domains. For example, if you tend to be picky while shopping for groceries, you'll probably be picky shopping for clothes, as well."
Meloy said the findings also illustrate the importance of a company understanding and tailoring their business practices to their customer base.
"If you know you have a lot of picky customers, you might not want to bother with offering free products or promoting products by saying how popular they are with other people," Meloy said. "It's just not going to work as well with picky customers. These companies will need to come up with strategies that give customers more control to better align their idiosyncratic preferences with the company's offerings."
Hans Baumgartner, Smeal Chair Professor of Marketing at Penn State, also participated in this work.
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Study finds green spaces linked to lower racial disparity in COVID infection rates
A new study is the first to examine the relationship between the supply of green spaces and reduced disparity in infectious disease rates.
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU
IMAGE: FROM LEFT, RESEARCHERS BIN JIANG, YI LU AND WILLIAM SULLIVAN FOUND THAT MORE GREEN SPACES IN AN AREA IS ASSOCIATED WITH A LOWER RACIAL DISPARITY IN CORONAVIRUS INFECTION RATES. THEIR... view more
CREDIT: PHOTOS COURTESY BIN JIANG, YI LU AND WILLIAM SULLIVAN
CHAMPAIGN, Ill. -- A higher ratio of green spaces at the county level is associated with a lower racial disparity in coronavirus infection rates, according to a new study. It is the first study to report the significant relationship between the supply of green spaces and reduced disparity in infectious disease rates.
The research team included William Sullivan, a landscape architecture professor at the University of Illinois Urbana-Champaign, and was led by Bin Jiang, a landscape architecture professor at The University of Hong Kong who received his Ph.D. at Illinois, and Yi Lu, an architecture professor at City University of Hong Kong. They reported their findings in the journal Environment International.
Previous studies by Sullivan, Jiang and Lu have shown that green spaces have positive effects on health. Access to green spaces is associated with improved cognitive performance, reduced mental fatigue and stress, reduced impulsiveness and aggressiveness, increased sense of safety, reduced crime rate, increased physical activity and increased social cohesion.
Prior studies also provide strong evidence that green spaces may mitigate racial disparities in health outcomes. However, none have looked at the effect on disparities in infectious diseases. Most studies examining the racial disparity in coronavirus infections have focused on its association with socio-economic status or pre-existing chronic disease factors.
For this study, the researchers identified 135 of the most urbanized counties in the U.S., with a total population of 132,350,027, representing 40.3% of the U.S. population. They collected infection data from county health departments from late January to July 10, 2020, and used it to calculate the infection rates for Black and white residents of the counties, while controlling for differences in income, pre-existing chronic diseases and urban density.
The data showed that the average infection rate for Black residents was more than twice that of white residents - 497 per 100,000 people for white individuals versus 988 per 100,000 people for Black individuals.
The researchers compared the infection rates of each population within each county, rather than across all the counties studied. The county-level comparison Is critical because it can minimize the bias caused by differences of socioeconomic, transportation, climate and policy conditions among counties, they said.
Sullivan, Jiang and Lu said several factors could account for the findings. They proposed that a greater proportion of green spaces in a county makes it more likely that Black and white individuals have more equal access to the green spaces and the accompanying health benefits.
"In many, many counties, Black folks have less access to green space than white folks do. In counties with more green space, that disparity may be less, and it may help account for some of the positive benefits we're seeing," Sullivan said.
The coronavirus is spread through aerosol particles, and the spread is heightened in indoor settings without adequate ventilation. Having access to green spaces attracts people outdoors, where air movement and the ease of social distancing can reduce the spread of the virus.
More access to green spaces is likely to promote physical activity, which may enhance the immune system. Green spaces enhance mental health and reduce stress, which also promotes immune system health. They strengthen social ties, which is an important predictor of health and well-being, the researchers said. Green spaces also may decrease infection risk by improving air quality and decreasing exposure to air pollutants in dense urban areas.
"We did not measure these things, but we know from previous research that all these things are tied to green spaces and have implications for health and well-being," Sullivan said.
Jiang described green space as preventive medicine, encouraging outdoor physical activity and social ties with neighbors that will boost the immune system and promote social trust and cooperation to reduce risk of infections.
While the study looked at infection rates in the U.S., "we also think the racial disparity issue is not just an American issue. It's an international issue," Jiang said.
The research shows the importance for local and regional governments to invest in the development of green spaces, Sullivan said.
"One of the things the pandemic has helped us understand is that the built environment has real implications for the spread of disease and for our health. The design of landscape in cities, in neighborhoods, in communities also has really important ways it can contribute to or detract from health and well-being," he said. "There is a lot of competition for investment of public dollars. Lots of times, investments in parks and green spaces are prioritized lower. People think it makes a place look pretty and it's a place to go for walks. What we're finding is these kinds of investments have implications for health and well-being."
In wild soil, predatory bacteria grow faster than their prey
Predatory bacteria--bacteria that eat other bacteria--grow faster and consume more resources than non-predators in the same soil, according to a new study out this week from Northern Arizona University. These active predators, which use wolfpack-like behavior, enzymes, and cytoskeletal 'fangs' to hunt and feast on other bacteria, wield important power in determining where soil nutrients go. The results of the study, published in the journal mBio this week, show predation is an important dynamic in the wild microbial realm, and suggest that these predators play an outsized role in how elements are stored in or released from soil.
Like every other life form on earth, bacteria belong to intricate food webs in which organisms are connected to one another by whom they consume and how. In macro webs, ecologists have long understood that when resources like grass and shrubs are added to lower levels of the web, predators at the top, such as wolves, often benefit. The research team, led by Bruce Hungate and researchers from Northern Arizona University and Lawrence Livermore Laboratory, wanted to test whether the same was true in the microbial food webs found in wild soil.
"We've known predation plays a role in maintaining soil health, but we didn't appreciate how significant predator bacteria are to these ecosystems before now," said Hungate, who directs the Center for Ecosystem Science and Society at Northern Arizona University.
To understand who and how much predator bacteria were consuming, the research team assembled a big picture using dozens of smaller data "snapshots": 82 sets of data from 15 sites in a range of ecosystems. The team used information about how bacteria behave in culture to categorize bacteria as obligate or facultative predators. About seven percent of all bacteria in the meta-analysis were identified as predators, and the majority of those were facultative, or omnivorous.
Obligate predator bacteria like Bdellovibrionales and Vampirovibrionales grew 36 percent faster and took up carbon 211 percent faster than non-predators did. When the soil received a boost of carbon, predator bacteria used it to grow faster than other types. Researchers saw these effects in the omnivorous bacteria, as well, though the differences were less profound.
All the experiments were conducted using a state-of-the-art technique called quantitative Stable Isotope Probing, or qSIP. Researchers used labeled isotopes, which act a little like molecular hashtags, to track who is active and taking up nutrients in the soil. By sequencing the DNA in a soil sample and looking for these labels, the team could see who was growing and eating whom at the level of bacterial taxa.
"While analyzing my data, I noticed that Vampirovibrio was super enriched. Since we know Vampirovibrio is a predator, I became interested in looking for other potential predators in my other data," said Brianna Finley, a postdoctoral research at University of California-Irvine and co-author on the study. "That we could pick up on these signals really validates qSIP as a tool."
Soil ecosystems contain more carbon than is stored in all the plants on Earth, so understanding how carbon and other elements move among soil organisms is crucial to predicting future climate change. And because bacteria are so abundant in soil, they have an enormous role in how nutrients are stored there or lost. And learning more about how predator bacteria act as 'antibiotics' could have therapeutic implications, down the road.
"Until now, predatory bacteria have not been a part of that soil story," said Hungate. "But this study suggests that they are important characters who have a significant role determining the fate of carbon and other elements. These findings motivate us to take a deeper look at predation as a process."
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The research was supported by the Department of Energy's Office of Biological and Environmental Research Genomic Sciences Program, and a Lawrence Fellow award from the Lawrence Livermore National Laboratory.
While evolution is normally thought of as occurring over millions of years, researchers at the University of California, Irvine have discovered that bacteria can evolve in response to climate change in 18 months. In a study published in the Proceedings of the National Academy of Sciences, biologists from UCI found that evolution is one way that soil microbes might deal with global warming.
Soil microbiomes - the collection of bacteria and other microbes in soil - are a critical engine of the global carbon cycle; microbes decompose the dead plant material to recycle nutrients back into the ecosystem and release carbon back into the atmosphere. Multiple environmental factors influence the composition and functioning of soil microbiomes, but these responses are usually studied from an ecological perspective, asking which microbial species increase or decrease in abundance as environmental conditions change. In the current study, the UCI team investigated if bacterial species in the soil also evolve when their environment changes.
"We know that evolution can occur very fast in bacteria, as in response to antibiotics, but we do not know how important evolution might be for bacteria in the environment with ongoing climate change," said Dr. Alex Chase, the lead author of the study and a former graduate student at UCI.
Several inherent characteristics should enable soil microbes to adapt rapidly to new climate conditions. Microbes are abundant and can reproduce in only hours, so a rare genetic mutation that allows for adaptation to new climate conditions might occur by chance over a short time frame. However, most of what is known about bacterial evolution is from controlled laboratory experiments, where bacteria are grown in flasks with artificial food. It was unclear whether evolution happens fast enough in soils to be relevant to the effects of current rates of climate change.
"Current predictions about how climate change will affect microbiomes make the assumption that microbial species are static. We therefore wanted to test whether bacteria can evolve rapidly in natural settings such as soil," explained Dr. Chase.
To measure evolution in a natural environment, the researchers deployed a first-ever bacterial evolution experiment in the field, using a soil bacterium called Curtobacterium. The researchers used 125 "microbial cages" filled with microbial food made up of dead plant material. (The cages allow the transport of water, but not other microbes.) The cages then exposed the bacteria to a range of climate conditions across an elevation gradient in Southern California. The team conducted two parallel experiments over 18 months measuring both the ecological and evolutionary responses in the bacteria.
"The microbial cages allowed us to control the types of bacteria that were present, while exposing them to different environmental conditions in different sites. We could then test, for instance, how the warm and arid conditions of the desert site affected the genetic diversity of a single Curtobacterium species," said Dr. Chase.
After 18 months, the scientists sequenced bacterial DNA from the microbial cages of the experiments. In the first experiment containing a diverse soil microbiome, different Curtobacterium species changed in abundance, an expected ecological response. In the second experiment over the same time frame, the genetic diversity of a single Curtobacterium bacterium changed, revealing an evolutionary response to the same environmental conditions. The authors conclude that both ecological and evolutionary processes have the potential to contribute to how a soil microbiome responds to changing climate conditions.
"The study shows that we can observe rapid evolution in soil microbes, and this is an exciting achievement. Our next goal is to understand the importance of evolutionary adaptation for soil ecosystems under future climate change," said co-author Jennifer Martiny, professor of ecology and evolutionary biology who co-directs the UCI Microbiome Initiative.
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Researchers who contributed to this work were: Alexander Chase, Claudia Weihe, and Jennifer Martiny.
The study was supported by the Scripps Institution of Oceanography Postdoctoral Scholar Fellowship, the National Science Foundation and the U.S. Department of Energy Office of Science, Biological and Environmental Research.
About the University of California, Irvine: Founded in 1965, UCI is the youngest member of the prestigious Association of American Universities and is ranked among the nation's top 10 public universities by U.S. News & World Report. The campus has produced three Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UCI has more than 36,000 students and offers 224 degree programs. It's located in one of the world's safest and most economically vibrant communities and is Orange County's second-largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UCI, visit http://www.uci.edu.
Media access: Radio programs/stations may, for a fee, use an on-campus ISDN line to interview UCI faculty and experts, subject to availability and university approval. For more UCI news, visit news.uci.edu. Additional resources for journalists may be found at communications.uci.edu/for-journalists.
Socially just population policies can mitigate climate change and advance global equity
CORVALLIS, Ore. - Socially just policies aimed at limiting the Earth's human population hold tremendous potential for advancing equity while simultaneously helping to mitigate the effects of climate change, Oregon State University researchers say.
In a paper published this week in Sustainability Science, William Ripple and Christopher Wolf of the OSU College of Forestry also note that fertility rates are a dramatically understudied and overlooked aspect of the climate emergency. That's especially true relative to the attention devoted to other climate-related topics including energy, short-lived pollutants and nature-based solutions, they say.
"More than 11,000 scientists from 153 countries have come together to warn that if we continue with business as usual, the result will be untold human suffering from climate change," Ripple said. "We have listed six areas, including curbing population growth in the context of social justice, as a framework for action.
"Since 1997, there have been more than 200 articles published in Nature and Science on climate mitigation, but just four of those discussed social justice, and only two considered population," he added. "Clearly social justice and population policy are not getting the attention they deserve in the struggle against the climate emergency."
The Earth's 7.7 billion people contribute to climate change in a variety of ways, primarily through the consumption of natural resources, including non-renewable energy sources, and the greenhouse gas emissions that result from industrial processes and transportation. The more people there are on the planet, the more potential they have for affecting climate.
Partly due to forced sterilization campaigns and China's one-child policy, population policies have long been viewed as a taboo topic and detrimental to social justice, Wolf says, but they can be just the opposite when developed and implemented appropriately with the goal of promoting human rights, equity and social justice.
"There are strong links between high rates of population growth and ecosystem impacts in developing countries connected to water and food security," he said. "Given the challenges of food and water security, effective population policies can support achieving both social justice and climate adaptation, particularly when you consider the current and projected uneven geographical distribution of the impacts of climate change. Policies that address health and education can greatly reduce fertility rates."
Examples of badly needed population policy measures include improving education for girls and young women, ending child marriage and increasing the availability of voluntary, rights-based family planning services that empower all people and particularly poor women, the researchers say.
"Three examples of countries in which improved education for girls and young women may have contributed to significant fertility rate declines are Ethiopia, Indonesia and Kenya," Ripple says. "Among those nations, specific education reforms included instituting classes in local languages, increasing budgets for education and removing fees for attending school. Ethiopia also implemented a school lunch program, large-scale school construction took place in Indonesia, and primary school was lengthened by one year in Kenya."
As part of an overall climate justice initiative, the scientists say, rich countries should do more to help fund voluntary family planning and educational opportunities for girls and young women in developing nations.
"It's not a balanced approach to focus on fertility rates without remembering that wealthy governments, corporations and individuals have been the primary contributors to carbon dioxide emissions and the main beneficiaries of fossil fuel consumption," Wolf said, noting the richest half of the world's population is responsible for 90% of the CO2 emissions.
"From both climate and social justice perspectives, affluent overconsumption by the wealthy must be addressed immediately, for example through policies like eco-taxes such as carbon pricing," Ripple added. "Reducing fertility rates alone is clearly not enough. The middle class and rich must be responsible for most of the needed reduction in emissions."
Taking steps to stabilize and then gradually reduce total human numbers within a socially just framework enhances human rights and reduces the further ordeals of migration, displacement and conflict expected in this century, Wolf and Ripple say. One potential framework is contraction and convergence, which calls for simultaneously reducing net emissions (contraction) while equalizing per capita emissions (convergence). This is equitable in the sense that it entails equalizing per capita emissions globally, a stark contrast to current patterns.
"Social justice and the climate emergency demand that equitable population policies be prioritized in parallel with strategies involving energy, food, nature, short-lived pollutants and the economy," Ripple said. "With feedback loops, tipping points and potential climate catastrophe looming, we have to be taking steps in all of those areas and not ignoring any of them."
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Eileen Crist of Virginia Tech joined Ripple and Wolf in authoring the paper.
Uncertainty of future Southern Ocean CO2 uptake cut in half
Anyone researching the global carbon cycle has to deal with unimaginably large numbers. The Southern Ocean - the world's largest ocean sink region for human-made CO2 - is projected to absorb a total of about 244 billion tons of human-made carbon from the atmosphere over the period from 1850 to 2100 under a high CO2 emissions scenario. But the uptake could possibly be only 204 or up to 309 billion tons. That's how much the projections of the current generation of climate models vary. The reason for this large uncertainty is the complex circulation of the Southern Ocean, which is difficult to correctly represent in climate models.
"Research has been trying to solve this problem for a long time. Now we have succeeded in reducing the great uncertainty by about 50 percent," says Jens Terhaar of the Oeschger Centre for Climate Change Research at the University of Bern.
Together with Thomas Frölicher and Fortunat Joos, who are also researchers at the Oeschger Centre, Terhaar has just presented in the scientific journal "Sciences Advances" a new method for constraining the Southern Ocean's CO2 sink. The link between the uptake of human-made CO2 and the salinity of the surface waters is key to this. "The discovery that these two factors are closely related helped us to better constrain the future Southern Ocean CO2 sink " explains Thomas Frölicher.
Towards achieving the Paris climate target
A better constraint Southern Ocean carbon sink is a prerequisite to understand future climate change. The ocean absorbs at least one fifth of human-made CO2 emissions, and as such slows down global warming. By far the largest part of this uptake, about 40 percent, occurs in the Southern Ocean.
The new calculations from Bern not only reduce uncertainties in CO2 uptake and thus allow more accurate projections, but also show that by the end of the 21st century the Southern Ocean will absorb around 15 percent more CO2 than previously thought. This is only a tiny bit of help on the extremely challenging path to achieving the Paris temperature goal of 1.5 degree. "The reduction of human-made CO2 emissions resulting from the combustion of fossil fuels remains extremely urgent if we are to achieve the goals of the Paris climate agreement," clarifies Fortunat Joos.
Better model predictions possible
In their study, the three climate scientists show why the salinity content of the ocean surface waters is a good indicator of how much human-made CO2 is transported into the ocean interior. Models that simulate low salinity in the Southern Ocean surface waters have too light waters and therefore transport less water and CO2 into the ocean interior. As a result, they also absorb less CO2 from the atmosphere. Models with higher salinity, on the other hand, show higher absorption of CO2 from the atmosphere. The salinity of the Southern Ocean surface waters, determined through observations, allowed the researchers from Bern to narrow down the uncertainty in the various model projections.
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Publication details:
J. Terhaar, T. L. Frölicher, F. Joos: Southern Ocean anthropogenic carbon sink constrained by sea surface salinity. Sci. Adv. 7, eabd5964 (2021), April 28, 2021, doi: 10.1126/sciadv.abd5964 https://advances.sciencemag.org/content/7/18/eabd5964
Oeschger Centre for Climate Change Research
The Oeschger Centre for Climate Change Research (OCCR) is one of the strategic centers of the University of Bern. It brings together researchers from 14 institutes and four faculties. The OCCR conducts interdisciplinary research right on the frontline of climate change research. The Oeschger Centre was founded in 2007 and bears the name of Hans Oeschger (1927-1998), a pioneer of modern climate research, who worked in Bern. http://www.oeschger.unibe.ch
