Led by scientists at the Desert Research Institute (DRI), the study published June 11 in Earth’s Future. By identifying agricultural communities considered at-risk from looming changes in snowfall and snowmelt patterns, the researchers found that water conservation measures like changes in crop type and extent were more stable adaptive strategies than changes to reservoir capacity. By the end of the century, many areas could have less than half the water they have historically relied on to refill their reservoirs, but changing the types and extent of their crops could help by restoring an average of about 20% of reservoir capacity.

The research team included scientists with the diversity of expertise needed to capture the complexities of water systems while balancing concerns for locally focused adaptation. Beatrice Gordon, lead author of the study and sociohydrologist and postdoctoral researcher at DRI, says the research is needed to inform water management at the local level, where most decisions are made. Gordon herself grew up on a ranch in Wyoming, where she learned firsthand the challenges that face water-insecure communities — an experience that helped lead to her research focus on agriculture and water in the Western U.S.

“A lot of decisions about water are made at the local level, but there’s this big disconnect between that reality and the macro-scale level of most research on this topic,” Gordon says. “We really wanted to understand what the future could look like at the scale that most communities manage their water resources. What are the levers that folks in these communities have when it comes to a future with less snow?”

Mountain snowpacks have historically acted as nature’s water towers across much of the region by storing winter precipitation and releasing it downstream during drier months. Water management systems were designed with this process in mind, but climate change is altering snowmelt patterns in ways that will make it difficult for existing systems to meet the needs of downstream water users. As the world’s largest user of freshwater, irrigated agriculture is at particularly high risk from these changes.

Strategies for addressing water shortages that focus on augmenting supply include expanding reservoirs and replenishing groundwater with surplus water, but these approaches become less effective as the timing and availability of precipitation become more unpredictable. In contrast, water conservation strategies such as reducing total crop acreage, periodic crop fallowing, and shifting toward higher value crops can help manage these risks.

To find out how risk management practices could work on a community-level scale, the researchers built a comprehensive risk assessment framework based on guidance from the Intergovernmental Panel on Climate Change (IPCC). For each of 13 communities, they gathered historical data on irrigation water supply, agricultural water demand, snow storage and snowmelt patterns, and more. They then used projections for the future climate through 2100 to understand how supply and demand dynamics may change in the near future.

“We gathered all these data together and looked at the picture of risk, and then also the ways that adaptation could reduce risk,” Gordon says. “Our goal was really to make this as relevant as possible for the people who are actually making decisions on the ground.”

“Dr. Gordon assembled a very impressive and unprecedented dataset for this paper linking agricultural water supply and demand across the Western United States,” says study co-author Gabrielle Boisramé, assistant research professor at DRI.

The Western agricultural communities the researchers selected are located in headwaters areas, making them both subject to significant changes in future climate and sentinels for the future of the West. Several of them are located in the Upper Colorado River Basin, which feeds into the main stem of the river — a water system that supports more than 40 million people.

“A lot of these areas are providing downstream water to other communities,” Gordon says. “So, if they have an increase in demand and a decrease in supply, it impacts not only that area, but also the areas that rely on that water downstream.”

The study results show that there will be a stark decline in how much many of these communities will be able to refill their reservoirs in just a few decades, with some seeing declines to about half of the water they were historically able to store. A drop that significant is particularly acute in many of the smaller reservoirs that can only hold about a year’s worth of water.

“It shows how important it is to dedicate effort — now, not in 20 to 50 years — to figuring out how we, as scientists, can provide better information about water conservation,” Gordon says. “And I think that there’s an opportunity to really think about how we support communities in these efforts, especially small communities in headwaters regions that might be fully dependent on agriculture.”

“Our results indicate the importance of water conservation as an adaptive strategy in a warmer future with less snow,” she continues. “And that’s broadly true across a lot of different places in the Western U.S.”

The study does not prove that delivery of a low-birth-weight infant causes memory and thinking problems. It only shows an association.

“Previous research has shown that people who have had a low-birth-weight delivery have a higher risk of cardiovascular disease and high blood pressure,” said study author Diana C. Soria-Contreras, PhD, of the Harvard T.H. Chan School of Public Health in Boston, Massachusetts. “Our study found that a history of having a child with a low birth weight may also be a marker of poorer cognition later in life.”

The study involved 15,323 female participants with an average age of 62 at completion of thinking and memory tests. All the participants had at least one birth. Of the total participants, 1,224 people, or 8%, had a history of low-birth-weight delivery. Low birth weight was defined as less than 5.5 pounds for pregnancies lasting more than 20 weeks.

Participants completed a questionnaire about their pregnancy complications, birth outcomes, birth weight and other information.

They also completed a series of thinking and memory tests.

Researchers then combined average scores of the two tests of participants’ memory and ability to quickly and accurately respond to a situation as well as the two tests of learning and working memory. Higher scores indicated better memory and thinking. On average, the difference in scores between those with and without a low-birth-weight delivery was -0.06 for speed and attention tests and -0.05 for learning and working memory. This is comparable to the difference associated with one to two additional years of age in this population.

The results were similar after researchers adjusted for factors that could affect both birth weight and cognitive function, such as age, smoking status and high blood pressure. The results were also similar when researchers did not include people with premature deliveries, pregnancies with twins or other multiples or those affected by pregnancy-related high blood pressure disorders.

In addition, they found that the more low-birth-weight deliveries people had, the lower their scores were.

“Future research is needed to confirm our findings and to look at whether screening women with a history of low-birth-weight deliveries for cognitive issues and taking steps to promote their brain health could help prevent or delay cognitive impairment and dementia later on,” Soria-Contreras said.

A limitation of the study is that most of the participants were non-Hispanic white people, so results may not be generalizable to other populations.

The study was supported by the National Institute of Mental Health, the National Institute of Environmental Health Sciences, the National Institute on Aging and the Office of Research on Women’s Health.

Understanding what contributes to patients’ inactivity is the focus of a world first study from the University of South Australia. Here, researchers have found that people with knee OA unconsciously believe that activity may be dangerous to their condition, despite medical advice telling them otherwise.

The study found that of those surveyed, 69% of people with knee pain had stronger implicit (unconscious) beliefs that exercise was dangerous than the average person without pain.

It’s an interesting finding that not only highlights the conflicted nature of pain and exercise, but also that what people say and what people think, deep down, may be entirely different things.

Lead researcher, and UniSA PhD candidate based at SAHMRI, Brian Pulling, says the research provides valuable insights for clinicians treating people with knee OA.

“Research shows that physical activity is good for people with knee OA, but most people with this condition do not move enough to support joint or general health,” Pulling says.

“To understand why people with OA might not be active, research studies typically use questionnaires to assess fear of moving. But unfortunately, questionnaires are limited — what we feel deep down (and how our system naturally reacts to something that is threatening) may be different to what we report. And we still know that many people are avoiding exercise, so we wanted to know why.”

To assess this, the researchers developed a tool that can detect and evaluate people’s implicit beliefs about exercise; that is, whether they unconsciously think activity is dangerous for their condition.

“We found that that even among those who said they were not fearful about exercise, they held unconscious beliefs that movement was dangerous,” Pulling says.

“Our research shows that people have complicated beliefs about exercise, and that they sometimes say one thing if asked directly yet hold a completely different implicit belief.

“People are not aware that what they say doesn’t match what they choose on the new task; they are not misrepresenting their beliefs.

“This research suggests that to fully understand how someone feels about an activity, we must go beyond just asking directly, because their implicit beliefs can sometimes be a better predictor of actual behaviour than what people report. That’s where our tool is useful.”

The online implicit association test presents a series of words and images to which a participant must quickly associate with being either safe or dangerous. The tool intentionally promotes instant responses to avoid deliberation and other influencing factors (such as responding how they think they should respond).

Associate Professor Tasha Stanton says that the new tool has the potential to identify a group of people who may have challenges increasing their activity levels and undertaking exercise.

“What people say and what people do are often two different things, Assoc Prof Stanton says.

“Having access to more accurate and insightful information will help health professionals better support their patients to engage with activity and exercise. It may also open opportunities for pain science education, exposure-based therapy, or cognitive functional therapy…things that would not usually be considered for someone who said that they were not scared to exercise.”

Researchers are now looking to see if implicit beliefs are directly associated with behaviour and are asking for people to complete the Implicit Association Test (takes seven minutes). At the end of the test participants are given their results in comparison to the rest of the population.

To take the test, please click here: https://unisasurveys.qualtrics.com/jfe/form/SV_0OZKUqzBNtiKGF0

A team of researchers led by University of Wisconsin-Madison astronomy professor Catherine Grier and recent graduate Robert Wheatley revealed the accelerating gas using years of data collected from a quasar, a particularly bright and turbulent kind of black hole, billions of light years away in the constellation Boötes. They presented their findings today at the 244th meeting of the American Astronomical Society in Madison.

Scientists believe black holes are situated at the center of most galaxies. Quasars are supermassive black holes surrounded by disks of matter being pulled in by the black hole’s enormous gravitational power.

“The material in that disk is always falling into the black hole, and the friction of that pulling and pulling heats up the disk and makes it very, very hot and very, very bright,” says Grier. “These quasars are really luminous, and because there’s a large range of temperatures from the interior to the far parts of the disk, their emission covers almost all of the electromagnetic spectrum.”

The bright light makes quasars nearly as old as the universe (as many as 13 billion light years away) visible, and the broad range of their radiation makes them particularly useful for astronomers to probe the early universe.

Researchers used more than eight years of observations of a quasar called SBS 1408+544, collected by a program carried out by the Sloan Digital Sky Survey now known as the Black Hole Mapper Reverberation Mapping Project. They tracked winds composed of gaseous carbon by spotting light from the quasar that was missing — light that was being absorbed by the gas. But instead of being absorbed at exactly the right spot in the spectrum that would indicate carbon, the shadow shifted farther from home with every new look at SBS 1408+544.

“That shift tells us the gas is moving fast, and faster all the time,” says Wheatley. “The wind is accelerating because it’s being pushed by radiation that is blasted off of the accretion disk.”

Scientists, including Grier, have suggested they’ve observed accelerating winds from black hole accretion disks before, but this had not yet been backed by data from more than a few observations. The new results came from about 130 observations of SBS 1408+544 made over nearly a decade, which allowed the team to solidly identify the increase in velocity with high confidence.

The winds pushing gas out from the quasar are of interest to astronomers because they are a way in which the supermassive black holes might influence the evolution of the galaxies that surround them.

“If they’re energetic enough, the winds may travel all the way out into the host galaxy, where they could have a significant impact,” Wheatley says.

Depending on the circumstances, a quasar’s winds could supply pressure that squeezes gas together and speeds the birth of a star in its host galaxy. Or it could scour away that fuel and keep a potential star from forming.

“Supermassive black holes are big, but they’re really tiny compared to their galaxies,” says Grier, whose work is supported by the National Science Foundation. “That doesn’t mean they can’t ‘talk’ to each other, and this is a way for one to talk to the other that we will have to account for when we model the effects of these kinds of black holes.”

The study of SBS 1408+544, published today in The Astrophysical Journal included collaborators at York University, Pennsylvania State University, University of Arizona and others.

This research was funded in part by grants from the National Science Foundation (AST-2310211 and AST-2309930).

The research comprises two papers, one published in The Astrophysical Journal in April 2024, and one as yet unpublished that will be submitted to the same journal. The results will be presented at the 244th meeting of the American Astronomical Society, held June 9 through June 13 at the Monona Terrace Convention Center in Madison, Wisconsin. 

“Supermassive black holes in galaxy centers have millions-to-billions of times the mass of the Sun,” said Fan Zou, a graduate student at Penn State and first author of the papers. “How do they become such monsters? This is a question that astronomers have been studying for decades, but it has been difficult to track all the ways black holes can grow reliably.”

Supermassive black holes grow through a combination of two main channels. They consume cold gas from their host galaxy — a process called accretion — and they can merge with other supermassive black holes when galaxies collide.

“During the process of consuming gas from their hosting galaxies, black holes radiate strong X-rays, and this is the key to tracking their growth by accretion,” said W. Niel Brandt, Eberly Family Chair Professor of Astronomy and Astrophysics and professor of physics at Penn State and a leader of the research team. “We measured the accretion-driven growth using X-ray sky survey data accumulated over more than 20 years from three of the most powerful X-ray facilities ever launched into space.”

The research team used complementary data from NASA’s Chandra X-ray Observatory, the European Space Agency’s X-ray Multi-Mirror Mission-Newton (XMM-Newton), and the Max Planck Institute for Extraterrestrial Physics’ eROSITA telescope. In total, they measured the accretion-driven growth in a sample of 1.3 million galaxies that contained over 8,000 rapidly growing black holes.

“All of the galaxies and black holes in our sample are very well characterized at multiple wavelengths, with superb measurements in the infrared, optical, ultraviolet, and X-ray bands,” Zou said. “This allows for robust conclusions, and the data show that, at all cosmic epochs, more massive galaxies grew their black holes by accretion faster. With the quality of the data, we were able to quantify this important phenomenon much better than in past works.”

The second way that supermassive black holes grow is through mergers, where two supermassive black holes collide and merge together to form a single, even more massive, black hole. To track growth by mergers, the team used IllustrisTNG, a set of supercomputer simulations that model galaxy formation, evolution, and merging from shortly after the Big Bang until the present.

“In our hybrid approach, we combine the observed growth by accretion with the simulated growth through mergers to reproduce the growth history of supermassive black holes,” Brandt said. “With this new approach, we believe we have produced the most realistic picture of the growth of supermassive black holes up to the present day.”

The researchers found that, in most cases, accretion dominated black-hole growth. Mergers made notable secondary contributions, especially over the past 5 billion years of cosmic time for the most-massive black holes. Overall, supermassive black holes of all masses grew much more rapidly when the Universe was younger. Because of this, the total number of supermassive black holes was almost settled by 7 billion years ago, while earlier in the Universe many new ones kept emerging.

“With our approach, we can track how central black holes in the local universe most likely grew over cosmic time,” Zou said. “As an example, we considered the growth of the supermassive black hole in the center of our Milky Way Galaxy, which has a mass of 4 million solar masses. Our results indicate that our Galaxy’s black hole most likely grew relatively late in cosmic time.”

In addition to Zou and Brandt, the research team includes Zhibo Yu, graduate student at Penn State; Hyungsuk Tak, assistant professor of statistics and of astronomy and astrophysics at Penn State; Elena Gallo at the University of Michigan; Bin Luo at Nanjing University in China; Qingling Ni at the Max Planck Institute for Extraterrestrial Physics in Germany; Yongquan Xue at the University of Science and Technology of China; and Guang Yang at the University of Groningen in the Netherlands.

Funding from the U.S. National Science Foundation, the Chandra X-ray Center, and Penn State supported this work. The work was also made possible by the sharing of the IllustrisTNG simulation results with the scientific community.