The study will be published on May 29 in JAMA Network Open. It is the latest publication from the Apple Women’s Health Study, a longitudinal study of menstrual cycles, gynecological conditions, and overall women’s health conducted by Harvard Chan School, the National Institute of Environmental Health Sciences, and Apple.

“Our findings can lead to a better understanding of menstrual health across the lifespan and how our lived environment impacts this critical vital sign,” said co-principal investigator Shruthi Mahalingaiah, assistant professor of environmental, reproductive, and women’s health at Harvard Chan School.

While previous studies have shown trends towards earlier menarche over the past five decades, data has been limited on how these trends present within different racial groups and socioeconomic statuses. Additionally, few studies have had sufficient data to identify any trends regarding time to menstrual cycle regularity.

The researchers used the Apple Women’s Health Study’s large, diverse dataset to fill this research gap. Participants who enrolled in the study between November 2018 and March 2023 — 71,341 in total — self-reported the age at which they first began menstruating and their race and socioeconomic status. The researchers divided the participants into five age brackets: born between 1950-1969, 1970-1979, 1980-1989, 1990-1999, and 2000-2005. Ages of menarche were defined as early (younger than 11 years old), very early (younger than 9), and late (ages 16 and above). A subset of participants (61,932) self-reported the time it took for their menstrual cycle to become regular and were divided into five categories: up to two years, between three and four years, longer than five years, hasn’t become regular, or became regular with use of hormones. Another subset (9,865) provided their body mass index (BMI) at their age of menarche.

The study found that as birth year increased (meaning younger participants), average age at menarche decreased and time from menarche to menstrual cycle regularity increased. Among participants born from 1950-1969, the average age at menarche was 12.5 years, and the rates of early and very early menarche were 8.6% and 0.6%, respectively. Among participants born from 2000-2005, the average age of menarche was 11.9 years, and the rates of early and very early menarche were 15.5% and 1.4%, respectively. Across the two groups, the percentage of participants who reached menstrual cycle regularity within two years of menarche decreased from 76% to 56%. The researchers observed that these trends were present among all sociodemographic groups but were most pronounced among the participants who identified as Black, Hispanic, Asian, or mixed race, and who rated themselves as belonging to a low socioeconomic status.

The findings showed that BMI at age of menarche could explain part of the trend toward periods starting earlier — in other words, that childhood obesity, a risk factor for early puberty and a growing epidemic in the U.S., could be a contributing factor to earlier menarche. Other possible factors that might explain the trend include dietary patterns, psychological stress and adverse childhood experiences, and environmental factors such as endocrine-disrupting chemicals and air pollution.

“Continuing to investigate early menarche and its drivers is critical,” said corresponding author Zifan Wang, postdoctoral research fellow in Harvard Chan School’s Department of Environmental Health. “Early menarche is associated with higher risk of adverse health outcomes, such as cardiovascular disease and cancer. To address these health concerns — which our findings suggest may begin to impact more people, with disproportionate impact on already disadvantaged populations — we need much more investment in menstrual health research.”

The authors noted some limitations to the study, including that it relies heavily on retrospective self-reporting.

Other Harvard Chan School authors included Gowtham Asokan, Jukka-Pekka Onnela, Michelle Williams, Russ Hauser, and Brent Coull.

The study was made possible by funding from Apple, Inc. and the National Institutes of Health (grant Z01ES103333).

A new University of Michigan study concludes that nearly half of the food waste, about 620 million metric tons, could be eliminated by fully refrigerated food supply chains worldwide.

At the same time, fully refrigerated supply chains, or “cold chains,” could cut food waste-related emissions of climate-warming greenhouse gases by 41% globally, according to the study published online May 28 in the peer-reviewed journal Environmental Research Letters.

Sub-Saharan Africa and South and Southeast Asia have the greatest potential for reductions in both food losses and related emissions through increased cold-chain implementation, according to the study.

South and Southeast Asia could see a 45% reduction in food losses and a 54% decrease in associated emissions under an optimized refrigeration scenario. Sub-Saharan Africa has tremendous opportunities for both food loss (47%) and emissions (66%) reductions under optimized refrigeration conditions, the study shows.

And in many situations, developing more localized, less industrialized “farm-to-table” food supply chains may yield food savings comparable to optimized cold chains, according to the study.

“I was surprised to find the scale of our opportunity for reducing food loss and waste globally,” said study lead author Aaron Friedman-Heiman, a master’s student at U-M’s School for Environment and Sustainability and Ross School of Business. “Approximately half of the roughly 1.3 billion tons of food that goes to waste annually can be solved through food supply-chain optimization.”

The other author is Shelie Miller, a professor at U-M’s School for Environment and Sustainability and at the College of Engineering.

Food losses produce an estimated 8% of human-caused greenhouse gas emissions. The new U-M study focuses on food losses in the post-harvest to retail stages of the food supply chain and does not address on-farm or at-home losses.

The study accounts for the greenhouse gases emitted during food production. It does not include emissions tied to refrigeration or other supply-chain operations and does not include emissions from food waste in landfills.

The study, funded in part by Carrier Global Corp., found that:

• The greatest opportunity to improve food losses in less industrialized economies is the supply chain between the farm and the consumer. But in North America, Europe and other more industrialized regions, most food loss happens at the household level, so cold chain improvements would not have a major impact on total food losses.
• Reinforcing previous research, the U-M study highlights the importance of meat-related food losses. While the amount of fruit and vegetable losses is much higher, by weight, throughout the world, the climate-related emissions associated with meat losses are consistently greater than those associated with any other food type — due mainly to the high greenhouse gas intensity of meat production.
• Unlike previous studies of this topic, the U-M researchers compared the benefits of globalized, technologically advanced food-supply chains with those of localized “farm-to-table” food systems. “Hyper-localized food systems resulted in lower food losses than optimized global, refrigerated supply chains,” Friedman-Heiman said. “The results help quantify the value of maintaining and supporting local food chains.”

For the study, the researchers built a food-loss estimation tool to assess how improved access to the cold chain could impact food loss and its associated greenhouse gas emissions for seven food types in seven regions. They used data from the U.N. Food and Agriculture Organization and other sources.

By modeling food losses at each stage of the supply chain, the study highlights where the cold chain can be optimized to reduce food losses and emissions. The researchers analyzed the effects of moving from the current state of inconsistent and variable-quality cold chains throughout the world to an optimized system, defined as one with high-quality refrigeration across all stages.

The study estimates that poor cold-chain infrastructure could be responsible for up to 620 million metric tons of global food loss annually, resulting in emissions of 1.8 billion tons of carbon dioxide equivalents, the equivalent of 28% of U.S. annual greenhouse gas emissions.

The researchers say their adaptable, easy-to-use tool will be of use to anyone involved in the food supply chain, including farmers, grocery retailers, government officials and nongovernmental organizations.

“Although cold chain infrastructure is rapidly increasing worldwide, an optimized cold chain will likely develop at different rates and in different ways across the globe,” Miller said. “This analysis demonstrates that while increased refrigeration should lead to improvements in both food loss and greenhouse gas emissions associated with food loss, there are important tradeoffs associated with cold chain improvements by food type and region.”

She said Investment decisions will need to be prioritized to maximize the desired outcomes and impacts. For example, if an NGO’s top priority is ending hunger, then cold-chain upgrades that provide the greatest overall food-loss reductions may best meet that objective.

But organizations that prioritize climate action may choose to focus on reducing meat losses specifically, rather than total food losses.

The study found that meat accounts for more than 50% of food loss-related greenhouse gas emissions, despite accounting for less than 10% of global food losses by weight. Optimized refrigeration of meat could result in the elimination of more than 43% of emissions associated with meat loss, according to the study.

The researchers emphasize that the actual amount of greenhouse gas emissions savings will depend on the efficiency of cold-chain technologies and the carbon intensity of local electrical grids, since climate emissions associated with refrigeration can be significant.

The U-M study was supported by the U.S. National Science Foundation and by Carrier Global Corp., a global leader in intelligent climate and energy solutions.

Growing evidence suggests air pollution, which comprises toxic gases and particulate matter, might contribute to the onset of mental health problems. It is thought that pollution could negatively affect mental health via numerous pathways, including by compromising the blood-brain barrier, promoting neuroinflammation and oxidative stress, and directly entering the brain and damaging tissue.

Despite youth being a key period for the onset of these problems, until now, relatively few studies have investigated the associations of air and noise exposure during early life with mental health.

In this new study, researchers sought to examine the long-term impact of air and noise pollution exposure during pregnancy, early childhood and adolescence on three common mental health problems: psychotic experiences (including hallucinations, such as hearing or seeing things that others cannot, and delusions, such as having very paranoid thoughts), depression and anxiety.

To investigate this, the team used data from over 9,000 participants from Bristol’s Children of the 90s birth cohort study (also known as the Avon Longitudinal Study of Parents and Children), which recruited over 14,000 pregnant women from the Bristol area between 1991 and 1992, and has followed the lives of the women, the children and their partners ever since.

By linking participants’ early childhood data with their mental health reports at the ages of 13, 18 and 24 years, researchers were able to use this to map against outdoor air and noise pollution in South West England at different time points.

Researchers found that relatively small increases in fine particulate matter during pregnancy and childhood were associated with more psychotic experiences and depression symptoms many years later in teenage years and early-adulthood. These associations persisted after considering many related risk factors, such as family psychiatric history, socioeconomic status, and other area-level factors such as population density, deprivation, greenspace and social fragmentation.

The team found that every 0.72 micrograms per cubic meter increase in fine particulate matter (PM_2.5) during pregnancy and childhood was associated with an 11 per cent increased odds and 9 per cent increased odds for psychotic experiences, respectively; while exposure in pregnancy was associated with a 10 per cent increased odds for depression. In contrast, higher noise pollution exposure in childhood and teenage years was subsequently associated with more anxiety symptoms.

Dr Joanne Newbury, Sir Henry Wellcome Postdoctoral Research Fellow in the University’s Bristol Medical School: Population Health Sciences (PHS) and the study’s lead author, said: “Childhood, adolescence, and early adulthood are critical periods for the development of psychiatric disorders: worldwide, nearly two-thirds of those affected become unwell by the age of 25. Our findings add to a growing body of evidence — from different populations, locations, and using different study designs — suggesting a detrimental impact of air pollution (and potentially noise pollution) on mental health.

“This is a major concern, because air pollution is now such a common exposure, and rates of mental health problems are increasing globally. Given that pollution is also a preventable exposure, interventions to reduce exposure, such as low emissions zones, could potentially improve mental health. Targeted interventions for vulnerable groups including pregnant women and children could also provide an opportunity for more rapid reductions in exposure.

“It is important to emphasise that these findings, by themselves, do not prove a causal association. However, other recent studies have shown that low emissions zones appear to have a positive impact on mental health.”

The research, which involved researchers from King’s College London, University College London and Cardiff University, was funded by the University of Bristol, Wellcome, Economic and Social Research Council (ESRC), Medical Research Council (MRC), National Institute for Health and Care Research (NIHR), and the Natural Environment Research Council (NERC).

The researchers’ findings, which were recently published in Nature Communications Biology, highlight their discovery of the lipid-lowering effects of nesfatin-1-like peptide (NLP). This newly identified peptide — or small protein — is a close relative of nesfatin-1 (NESF-1), which regulates feed intake and body weight.

“We found that both NESF-1 and NLP lower lipid (fat) accumulation in human liver cells,” said research team member Dr. Suraj Unniappan (PhD), the university’s Centennial Enhancement Chair in Comparative Endocrinology and a professor at the Western College of Veterinary Medicine (WCVM). The collaborative study involved researchers at the WCVM and USask College of Medicine.

While the lipid-lowering effect of nesfatin-1 was previously reported, Unniappan said identifying NLP and understanding its lipid-lowering capabilities in human cells represent new advancements in the field of endocrinology.

“We are far away from bringing these findings to bedside,” said Unniappan. “But we now have additional multiple targets available that could be explored for lipid disease treatment and therapeutic advancements.”

The research team’s discovery is hopeful news since there’s a lack of new therapies for many metabolic diseases — including non-alcoholic fatty liver disease (recently renamed as metabolic dysfunction-associated steatotic liver disease or MAFLD), which affects about 20 per cent of Canadians. A hormone-based drug was approved in the United States in March 2024, but so far, there are no drugs currently available in Canada exclusively for treating this disease.

Typical treatment plans for both humans and animals suffering from metabolic disease generally consist of diet and exercise changes to gradually lower body weight and reduce fat accumulation.

Unniappan and his research team have been at the forefront of nesfatin-1 research. Discovered in 2006 by a group of researchers in Japan, nesfatin-1 was initially recognized for its ability to suppress food intake.

The USask team went a step further than previous studies and successfully verified that genetic disruption of NLP leads to changes in genes involved in lipid metabolism in mice.

“We found that if you disrupt the gene that is the source of that protein [NLP] naturally present in these animals, then that actually leads to changes in lipid metabolism-associated genes,” said Unniappan.

Discovering such results — that administering NLP reduces lipid levels, while disrupting its production alters lipid metabolism — reinforces its pivotal role in metabolic regulation.

Unniappan and Dr. Atefeh Nasri (PhD), who completed her doctoral program at USask in 2023 and is now a post-doctoral fellow at Dalhousie University, collaborated with Dr. Scott Widenmaier (PhD), an assistant professor of anatomy, physiology and pharmacology, and an expert in metabolic disease at the USask College of Medicine. The team’s fourth member was undergraduate student Mateh Kowaluk.

Unniappan hopes that this new research can pave the way for further exploration of treatment options. He plans to work with collaborators to extend this research to more complex animal models — including rodents — and eventually studying larger animals such as cats and dogs. Like humans, these species also suffer from obesity and related metabolic disorders.

“It’s beautiful to know the same peptide can achieve so many meritorious health effects, that in combination have the potential to help both human and animal patients,” said Unniappan.

This research was supported by the Canadian Institutes of Health Research (CIHR) and the USask Centennial Enhancement Chair in Comparative Endocrinology.

Reducing carbon emissions from small-scale combustion systems, such as boilers and other industrial equipment, is a key step towards building a more sustainable, carbon-neutral future. Boilers are widely used across various industries for essential processes like heating, steam generation, and power production, making them significant contributors to greenhouse gas emissions.

Boilers are generally quite efficient. As a result, it is difficult to reduce CO₂ emissions simply by improving the combustion efficiency. Therefore, researchers are exploring alternative approaches to mitigating the environmental impact of CO₂ emissions from boilers. One promising strategy to this end is to capture the CO₂ emitted from these systems and convert it into a useful product, such as methane.

To implement this strategy, a specific type of membrane reactor, called the distributor-type membrane reactor (DMR), is needed that can facilitate chemical reactions as well as separate gases. While DMRs are used in certain industries, their application for converting CO₂ into methane, especially in small-scale systems like boilers, has remained relatively unexplored.

This research gap was addressed by a group of researchers from Japan and Poland, who were led by Professor Mikihiro Nomura from Shibaura Institute of Technology in Japan and Prof. Grzegorz Brus from AGH University of Science and Technology in Poland. Their findings were published online on 17 April 2024 in Volume 82 of the Journal of CO2 Utilization.

The team conducted a two-pronged approach to the problem through numerical simulations and experimental studies to optimize the reactor designs for efficient conversion of CO₂ from small boilers into methane. In their simulation, the team modeled how gases flow and react under different conditions. In turn, this enabled them to minimize the temperature variations, ensuring that energy consumption is optimized while methane production remains dependable.

The team further found that, unlike traditional methods that channel gases into a single location, a distributed feed design could spread the gases out into the reactor instead of sending them in from one place. This, in turn, results in a better distribution of CO₂ throughout the membrane, preventing any location from overheating. “This DMR design helped us reduce temperature increments by about 300 degrees compared to the traditional packed bed reactor,” explains Prof. Nomura.

Beyond the distributed feed design, the researchers also explored other factors influencing the reactors efficiency and discovered that one key variable was the CO₂ concentration in the mixture. Changing the amount of CO₂ in the mixture affected how well the reaction worked. “When the CO₂ concentration was around 15%, similar to what comes out of the boilers, the reactor was much better at producing methane. In fact, it could produce about 1.5 times more methane compared to a regular reactor that only had pure CO₂ to work with,” highlights Prof. Nomura.

Additionally, the team investigated the impact of reactor size, finding that increasing the size of the reactor facilitated the availability of hydrogen for the reaction. There was, however, a tradeoff to be considered as the benefit of higher hydrogen availability required careful temperature management to avoid overheating.

The study thus presents a promising solution to the problem of tackling a major source of greenhouse gas emissions. By utilizing a DMR, low-concentration CO₂ emissions can be successfully converted into usable methane fuel. The benefits gained thereof are not limited to methanation alone but can also be applied to other reactions, making this method a versatile tool for efficient CO₂ utilization even for households and small factories.

Researchers from Chiba University have discovered that snails living in downstream tidal areas have biological rhythms synchronized with the tidal cycles, unlike those in nontidal regions. This observation raises the question of whether circatidal rhythms develop due to differences in habitat or are caused by genetic variations between the populations.

Building on their previous findings, Associate Professor Yuma Takahashi, along with Dr. Takumi Yokomizo from Chiba University (at the time of the study, and currently a post-doc researcher at the Center for Ecological Research, Kyoto University), revealed that freshwater snails living in tidal environments gradually adjust their biological rhythms to synchronize with the tidal cycles. The study published in the journal Heredity on March 27, 2024, offers insights into the adaptability and potential divergence of biological rhythms in response to tidal environments.

“This study revealed genetic and non-genetic changes in biological rhythms while adapting to tidal environments in a freshwater snail. This result could lead to an understanding of the role of biological clocks in the adaptation to rhythmic environment, which is one of the most important issues in chronobiology,” says Dr. Takahashi. The researchers collected freshwater snails (Semisulcospira reiniana) from tidal and nontidal areas along the Kiso River in Japan, 20 km apart. Snails were divided into two groups: one exposed to a regular 24-hour light-dark cycle, while the other experienced a simulated 12-hour tidal cycle, alternating between submersion during high tide and exposure to air during low tide.

Following a 4-week entrainment period, the researchers analyzed the behavior and genetic expression patterns of the snails in darkness at a constant temperature of 23°C. Among the snails from non-tidal areas, there were no significant differences in the intensity of the circadian and circatidal rhythms between the two groups. However, snails from tidal areas that were exposed to the simulated tidal cycle showed stronger circatidal rhythms compared to the control group. Interestingly, both the tidal and non-tidal populations exposed to the simulated tide showed an increase in the number of circatidal oscillating genes and a decrease in the circadian oscillating genes (genes that fluctuate in activity in tune with the tidal and diurnal cycle, respectively). Snails that had already adapted to the tidal cycles in the rivers in their early life had a greater number of circatidal oscillating genes compared to the nontidal population.

These results imply that the expression rhythms of genes controlled by the biological clock are sensitive to environmental changes, and can be influenced by genetic changes that result from environmental adaptation. “Our study focused on the flexibility of biological clocks and found their potential to change biological rhythms according to dominant environmental cycles,” says Dr. Takahashi.

Disruptions to biological rhythms can negatively impact various physiological processes. The findings of this study may enhance our understanding of how organisms adapt to changing environmental conditions and prove valuable in the treatment of chronobiological diseases in the future.

By analyzing the dynamics of 12 back-to-back explosions that happened in 2018, researchers describe a new type of volcanic eruption mechanism. The explosions were driven by sudden pressure increases as the ground collapsed, which blasted plumes of rock fragments and hot gas into the air, much like a classic stomp-rocket toy.

Researchers from the University of Oregon, United States Geological Survey and China’s Sichuan University report their findings in a paper published May 27 in Nature Geoscience.

The particular string of explosions at the summit of Kīlauea was part of a sequence of events that included lava flows erupting from lower on the flank of the volcano. Those lava flows destroyed thousands of homes and displaced residents on the Island of Hawai’i for months.

Understanding exactly what happened in past volcanic eruptions, colloquially called “hindcasting,” allows volcanologists to make better forecasts about future eruptions and give more accurate warnings to people in an eruption’s path.

For the most part, explosive volcanic eruptions are either primarily driven by rising magma, vaporized groundwater, or some combination of the two, according to Josh Crozier, who did this research as a doctoral student at the UO. But these eruptions didn’t quite fit the mold.

“These eruptions are quite interesting in that they don’t really seem to involve either of those,” Crozier said. “The eruptive material contained very little that looked like fresh magma that was blasted out, but there’s no evidence for significant groundwater being involved, either.”

The Hawaiian Volcano Observatory, part of the U.S. Geological Survey, keeps close tabs on Kīlauea. The volcano is covered with scientific instruments, from ground sensors that measure the shaking of the earth to tools that analyze the gases released from the volcano.

“A cool thing about these eruptions is that there were a bunch of them in sequence that were remarkably similar; that’s relatively unusual,” said Leif Karlstrom, a volcanologist at the UO. “Typically, volcanic eruptions don’t happen with as much regularity.”

So the team had more data than usual to work with, and they could dig deeper into the specific dynamics of the eruptions.

Putting all that data into a variety of atmospheric and subsurface models, the scientists pieced together a new story about what happened on Kīlauea during the string of events in 2018.

Before each explosion at the summit, magma was slowly draining from an underground reservoir. (This magma was feeding lava flows 40 kilometers away, on the eastern flank of the volcano.) As the reservoir depleted, the ground above it — the crater within the caldera at the volcano’s summit — suddenly collapsed.

That quickly increased the pressure in the reservoir. And because there was a pocket of accumulated magmatic gas sitting at the top of this reservoir, the pressure increase squeezed the magmatic gas and bits of rubble through a conduit and blasted them out of a vent in Kīlauea’s crater.

The researchers compare the eruption dynamic to a stomp-rocket toy, where stepping on an air bag connected to a hose launches a projectile into the air.

“The ‘stomp’ is this whole kilometer-thick chunk of rock dropping down, pressurizing the pocket, and then forcing material directly up,” Crozier said. And the ‘rocket’ is, of course, the gas and rocks erupting from the volcano.

Caldera collapse is fairly common, Crozier notes. So while this is the first time scientists have specifically spelled out this specific stomp-rocket mechanism, it’s probably not the only time it’s occurred.

The study was able to link geophysical observations to the properties of the volcanic plume in the atmosphere.

“This link is very rare,” said Joe Dufek, a volcanologist at the UO. “It points to new ways for us to observe eruptions and to combine sensor measurements with computer simulations to better assess hazards from eruptions.”

The fact that this was a series of smaller eruptions may have made it easier to see the underlying mechanism, Dufek said. Other complex processes weren’t overshadowing the stomp-rocket component.

But that’s not to say that Kīlauea is simple. A typical textbook drawing of a volcano shows magma moving upwards through chambers at different depths. But it’s rarely that straightforward, and a volcano like Kīlauea, decked out in scientific instruments, provides an opportunity to dig into the details.

“This is an example, and there’s an increasing number of these, where the pathways of magma ascent are quite geometrically complex,” Karlstrom said. “It gives us a much more nuanced picture of what volcanic plumbing systems look like.”