Wednesday, January 18, 2023

EMOTIONAL PLAGUE

Negative marital communications leave literal, figurative wounds

Study links destructive interaction patterns to lower immune function

Peer-Reviewed Publication

OHIO STATE UNIVERSITY

COLUMBUS, Ohio – A tendency for one or both spouses to avoid or withdraw from tough conversations could set up married couples for emotional distress, bad feelings about their relationship, chronic inflammation and lowered immune function, new research suggests.

The analysis revisits data from a 2005 Ohio State University study that showed the stress couples feel during a brief argument could slow their bodies’ ability to heal from wounds by at least a day – a landmark finding at the time showing how psychological stress affects immunity.

A fresh look at the data shows that when married couples typically communicate with each other in negative ways, both spouses – and women in particular – suffer emotionally and their immune function wanes, in the form of having wounds that take longer to heal. The analysis revealed that the health consequences of negative communication patterns were evident even before the 2005 study began: These couples arrived at the lab with higher blood markers for inflammation.

The initial trial showed that one stressful argument – in a lab, recorded and analyzed by researchers – could harm immune function. This new study suggests that the more combative arguments in the lab were linked to more negative typical marital communication for these couples – and those daily patterns are a likely culprit behind persistent negative emotions and biological markers that can lead to poorer health outcomes.

“Marriage is associated with better health, but chronically distressed marriages can worsen health,” said first author Rosie Shrout, who completed this work as a postdoctoral researcher in Ohio State’s Institute for Behavioral Medicine Research (IBMR). “It’s important to understand what is going on behind the scenes that contributes to these effects.

“What we’re seeing is that both chronic daily negativity and acute negativity, and their combination – experiencing both of those – is particularly bad for couples’ emotions, relationships and immune functioning,” said Shrout, now an assistant professor of human development and family science at Purdue University.

The new study was published recently in the journal Psychoneuroendocrinology.

The 2005 research was co-led by Jan Kiecolt-Glaser, senior author of the new study and professor emerita of psychiatry and psychology at Ohio State, whose decades of discoveries as a leader of the IBMR have shown the many ways in which stressful life events are detrimental to health.

The 2005 work involved 42 married heterosexual couples who had been together for an average of 12 years. Researchers tested the baseline level of a proinflammatory protein in their blood and used a device to raise small blisters on each partner’s forearm – the wounds’ healing progress was monitored as an indicator of how well each participant’s immune system was functioning.

Participants completed questionnaires assessing their typical communication patterns when problems arise – mutual constructive or symmetrical positive communication, or variations of negative communication patterns that involved either mutual avoidance or instances where one partner made demands and the other withdrew from the discussion in response.

Couples were recorded having discussions in two separate lab visits: The first focused on social support and the second was an attempt to resolve a known source of tension in the marriage, such as finances or in-laws. Researchers coded negative and positive behaviors during these talks.

In follow-ups, couples evaluated the discussions – whether they were satisfied with the conversation, and the degree to which they felt supported and understood by their partner, and in control and working productively while sorting out a problem. Their blister wound healing was assessed daily for eight days and then again on day 12.

In the new study, statistical modeling of the qualitative and biological data showed that couples’ negative communication patterns – specifically mutual avoidance or demand/withdrawal – had cascading effects on how they felt after the lab conversations, and on their inflammation and immune function measures.

“If they were more negative typically on a day-to-day basis, and were negative in those specific interactions, they rated the discussion more negatively and less positively, they felt fewer positive emotions, and their wounds healed more slowly,” Shrout said. “That chronic negativity and acute negativity had emotional, relational and immune effects – most notably for women.”

In contrast, couples who reported more mutual constructive communication patterns rated the lab conversations more favorably.

A few specific findings suggested how insidious the effects of poor communication patterns could be: Wounds healed more slowly in couples who mutually avoided talking about tough topics and also showed fewer positive behaviors during lab discussions. Even when mutual avoiders were more positive while trying to resolve conflict, that positivity didn’t help their wounds heal more quickly.

Kiecolt-Glaser, who has led a number of marriage and health studies, said it doesn’t take long for married couples to have expectations of what the marriage is like that can override any evidence to the contrary. In a bad marriage, a negative behavior is perceived as reinforcement of this expectation, while in a good marriage, a negative behavior is taken as a sign one’s partner is in distress.

“This study provides a window into relationships: What couples say about their relationship really did translate not only into how they behaved, but also what they said about the behavior, and their biology,” she said. “They walked into this study situation, and the way they’re responding may in part be because that’s what they’re expecting. They have such well-worn tracks in terms of interactions that it’s hard to derail the train.”

That doesn’t mean all is lost, Shrout noted – couples have lots of options to pursue education or therapy to help them learn better communication skills.

This work was supported by an Ohio State Presidential Postdoctoral Scholars Fellowship and the National Institutes of Health.

Additional co-authors include Megan Renna of the University of Southern Mississippi, and Annelise Madison and William Malarkey of Ohio State.

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Contacts:

Rosie Shrout, Shrout@purdue.edu
Jan Kiecolt-Glaser, Kiecolt-Glaser.1@osu.edu

Written by Emily Caldwell, Caldwell.151@osu.edu; 614-292-8152

 

Study indicates likely cause of common penis birth-defect

Peer-Reviewed Publication

WASHINGTON STATE UNIVERSITY

PULLMAN, Wash. –An alarming increase in the occurrence of the most common genital malformation in male babies, hypospadias, is likely due to environmental factors, such as toxicant exposure, which alter epigenetic programming in a forming penis. 

That’s according to a new study in Science Reports that identified a direct link between hypospadia tissue samples and the presence of epigenetic alterations, or changes to the molecular factors and processes around DNA that determine how genes behave. Conversely, epigenetic alternations were not found in penile tissue samples taken from the foreskin of healthy babies without hypospadias, according to the Washington State University-led analysis. 

The research helps answer long-standing questions surrounding the increased frequency and potential root cause of hypospadias, a birth defect in which the opening of the urethra is located on the underside of the penis instead of the tip. 

“Previous researchers have done extensive analyses and not found any kind of genetic DNA sequence mutations that correlate with the presence of the disease, so there has always been a big question mark regarding where it comes from,” said Michael Skinner, corresponding senior author of the study and a WSU professor of biology. “Our study shows the etiology of the disease is environmentally driven through epigenetics rather than a result of changes to the DNA sequence. It gives us a clearer picture of what is going on.” 

While the research is still in an early stage of development, it could ultimately lead to earlier detection and better clinical management of hypospadias, the prevalence of which has increased by 11.5% in recent decades, making it the most common genital malformation in newborn males. 

One potential path forward would be to identify a specific epigenetic biomarker that could be collected with a simple cheek swab from the parents of a baby to determine the likelihood of the newborn developing a hypospadia. 

“This is not so far-fetched,” Skinner said. “We have identified these types of biomarkers for other diseases. Early detection means they could do clinical management sooner which could result in fewer complications for the baby and more peace of mind for the parents.” 

A major question that remains to be answered is specifically what environmental factors (i.e. toxicants) are promoting the epigenetic alterations that are causing hypospadias. 

One potential culprit the researchers mentioned in the study is a pharmaceutical drug called diethylstilbestrol (DES) that was used in the late 50s and early 60s to ease the later stages of pregnancy for women. 

“There was never really evidence that it helped with pregnancy, but after the fact, doctors started to find severe developmental effects from the drug on babies. Hypospadias were one of the issues,” Skinner said. “Unfortunately, because epigenetic changes caused by drugs like this and other environmental toxicants are epigenetically heritable, they are often passed down from one generation to the next after they are contracted. Over time, the detrimental effects can persist and spread.” 

Another interesting finding from the study was that tissues samples with mild cases of hypospadias had a greater degree of epigenetic alterations than tissue samples with more severe versions of the disease. 

“What this suggests is that cells with really severe epigenetic alterations are probably dying and not surviving whereas a mild case of hypospadia will have lots of these diseased cells still alive,” Skinner said. “This gives us new insights into how epigenetic control is affecting tissue development.” 

This study was conducted in collaboration with researchers from the Departments of Pediatrics and Pediatric Urology at the Indiana University School of Medicine. Funding for the research was provided by the John Templeton Foundation. 

New initiative provides biomedical research experience to West Virginia high school students

Business Announcement

MARSHALL UNIVERSITY JOAN C. EDWARDS SCHOOL OF MEDICINE

HUNTINGTON, W.Va. – A new initiative at the Marshall University Joan C. Edwards School of Medicine offers West Virginia high school students an opportunity to explore the field of biomedical research while working to facilitate a more diverse research workforce across Appalachia. As part of the Health Care Pathways Initiative (HCPI), a four-week summer residential experience at Marshall University for minorities underrepresented in STEM careers, three local high school students will be selected for the new program that combines hands-on research experience with mentoring.   

Students will participate in three eight-week rotations throughout the school year, working in the laboratories of scientists at the Joan C Edwards School of Medicine. After completion of their research rotations, students will select a "permanent" mentor to work alongside for the rest of the program. Student participants will receive additional mentorship from teachers at their home high schools as well as junior graduate students or undergraduate mentors at Marshall.

Participating faculty members, undergraduate and graduate student trainees in their labs, and the high school trainees will meet for a bi-weekly lab and mentoring meeting that will include professional development training in topics such as time management, reading scientific literature, and careers in biomedical research. During the summer of 2023, students will perform full time research and have the opportunity to present their research findings at the WV-INBRE annual summer research symposium.  

“At Marshall, we are passionate about cultivating a passion for science and discovery that can impact the field of medicine and our communities for decades to come,” said Shelvy L. Campbell-Monroe, Ph.D., associate dean of diversity and inclusion for the Marshall University schools of medicine and pharmacy.

“This initiative is the first step in developing a comprehensive biomedical research pathway spanning high school students to postdoctoral trainees.” said Daniel Morgan, Ph.D., associate professor and vice chair of biomedical sciences at the Joan C. Edwards School of Medicine and principal investigator on the grant. “Our focus on high school students stems from a commitment to encourage scientific engagement and curiosity at a younger age.”

This project is funded by a one-year supplemental award from the National Institutes of Health (DA044999). The grant covers the cost of a paid research experience for the students, travel to the Annual Biomedical Research Conference for Minoritized Scientists (ABRCMS), as well as college entrance exams for student participants. Dr. Morgan and Dr. Brandon Henderson, Ph.D., associate professor and co-investigator on the grant, hope to seek additional funding to sustain and expand the program to include research training for minority undergraduate and graduate students as well as postdoctoral fellows.

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Early tastings shorten breastfeeding

Peer-Reviewed Publication

UPPSALA UNIVERSITY

The earlier infants begin to taste small samples of solid food, the earlier they eat more food and stop breastfeeding. This is shown in a new study from Uppsala University and Sophiahemmet University, in which the mothers of 1,251 infants from all over Sweden participated. Almost half of the infants received tastings at the age of four months.

“Existing research does not support the idea that the introduction of early tastings has health benefits for the child or the mother,” says Eva-Lotta Funkquist, Senior Lecturer and midwife, one of the researchers behind the article. “On the other hand, we know that breastfeeding has many health benefits for both the child and the mother. For example, the child is protected against infections while breastfeeding, and both mother and child have a reduced risk of cardiovascular diseases.”

Since 2011, the Swedish National Food Agency has advised parents that they can introduce tiny tastings for infants from four months of age. The World Health Organisation (WHO), in contrast, recommends breastfeeding exclusively for six months and continued breastfeeding for at least two years or longer. These recommendations apply to all the world’s countries, including Sweden, one reason being that breastfeeding has been scientifically confirmed to have major positive impacts on both women’s and children’s health. Breast milk contains substances that protect the child from infections such as pneumonia and urinary tract infections for the duration of breastfeeding. Breast milk also reduces the risk of the child being affected by cardiovascular disease, obesity and diabetes later in life. Women who breastfeed have a lower risk of being affected by cardiovascular diseases, ovarian cancer, breast cancer and type 2 diabetes.

A new study made by researchers at Uppsala University and Sophiahemmet University, published in the International Breastfeeding Journal, involved 1,251 infants from all over Sweden and their mothers. When the mothers answered questions about the child’s food during the first year of life by completing questionnaires, it emerged that around half of the children in the study, 48 per cent, received tastings as early as the fourth month. The earlier the infants started with tiny tastings, the earlier they ate larger quantities of solid food. This in turn led to an earlier end to breastfeeding and to a shorter duration of breastfeeding for these children.

Previous studies have shown that nearly all women say they want to breastfeed their child. Conflicting advice from the WHO and the Swedish National Food Agency, and recommendations unsupported by evidence, such as tiny tastings, make it more difficult for mothers who want to breastfeed to find support for doing so, and only 10 per cent of children in Sweden are fully breastfed for six months.

The United Nations (UN) states that breastfeeding ensures that the child can be fed safely in the event of war or crises, such as a failure of the energy supply or shortage of baby food. Previous research shows that more women’s lives than infants’ lives would be saved in western countries by following the recommendation of full breastfeeding for six months (Bartick MC, et al. (2016).

“For this reason, it is vitally important that public authorities in Sweden have recommendations that promote breastfeeding and are in line with the WHO recommendations. The risk otherwise is that mothers will stop breastfeeding earlier and that both the mother and the child will be at greater risk of adverse health consequences,” says Funkquist.

1 in 10 minors seeking abortions must pursue court approval, many are denied

In Florida, judges denied 13% of minors seeking abortion care through the 'judicial bypass' system

Peer-Reviewed Publication

UNIVERSITY OF COLORADO AT BOULDER

Twenty-two states, including Colorado, that have not banned abortion still do require those under age 18 to involve their parents before terminating a pregnancy. Their only other option: to seek approval from a judge via a process called judicial bypass.

New University of Colorado research published Jan. 12 in the American Journal of Public Health sheds new light on how many young people must navigate that process, shown in previous research to be traumatizing, and how frequently judges deny them care.

It found that more than one in 10 minors seeking abortions in Texas and Florida between 2018 and 2021 sought judicial bypass, and as many as 13% were denied. About 5,527 minors in Florida and 5,520 in Texas received abortions during the study period.

“States that support abortion rights but continue to mandate parental involvement have a responsibility to consider the true consequences of those mandates,” said co-author Amanda Stevenson, assistant professor of sociology at CU Boulder. 

She notes that due to recent statewide bans in the wake of the overturning of Roe v. Wade, many minors must now travel across state lines to seek care only to face parental involvement mandates far from home. 

“Our research shows that substantial numbers of adolescents cannot involve their parents and rely on judicial bypass, and that bypasses are routinely denied.”

A glimpse at Florida and Texas

For the study, Stevenson and co-author Kate Coleman-Minahan, assistant professor at University of Colorado College of Nursing at the Anschutz Medical Campus, analyzed data on bypass petitions and abortions provided to minors in Florida and Texas between 2018 and 2021. 

Florida moved from requiring parental notification to requiring consent in 2020. Texas has required parental consent for years and now has a total abortion ban.

In Texas, 10-14% of minors wishing to terminate a pregnancy during the study period had to seek permission through the courts.

In Florida, about 15% of minors seeking abortions sought judicial bypass, and judges denied care to about 13% of them. Denials there doubled over the study period. 

“Florida is more critical than ever as a source of abortion care, since it’s now the only place in the region to get an abortion after six weeks, so the fact that teenagers face such a large hurdle to get care there is significant,” said Stevenson.

The team’s previous research found that some teens seeking judicial bypass have experienced family trauma, household substance abuse, or a general fear for their own safety if they were to tell their parents they are seeking an abortion.

Once they begin the bypass process, they’re often confronted with challenges taking time off from school, getting to the courthouse and other obstacles.

Many reported finding the process humiliating and frightening, with judges and court-appointed guardians-ad-litem shaming them. 

Judges typically require minors to either provide evidence they are “mature” enough to have an abortion (things such as good grades or participation in extracurricular activities) or prove they can’t safely tell their parent, said Coleman-Minahan.

“They are often re-traumatized and re-victimized in court by having to describe their family situations,” she said.

Crossing state lines

The study also sheds some light on just how many teens from states where abortion is banned may be seeking abortions elsewhere and potentially running up against parental involvement laws.

“Teenagers who are traveling really far to get abortions will also have to involve their parents and get documentation of notification or consent to meet that state’s requirement,” said Stevenson. “That can be logistically challenging to the point of being impossible.”

One Massachusetts study found that complying with parental consent guidelines in state there took about nine days. For those who sought judicial bypass, it took 15.

Reasons for denials are not typically released, but previous studies have shown judges have denied bypasses based on family socioeconomic status, how far along a person was in their pregnancy or a judge’s personal values.

“Our research shows that young people are not just harmed by this process, they are denied abortions and that can have lifelong impacts,” said Stevenson.

The authors call on states such as Colorado and Maryland, that allow abortion access but mandate parental involvement, to routinely report the percentage of minors using the judicial bypass system so that coordinated services can be provided to help young people navigate it.

They also hope the data will demonstrate that parental involvement laws, which have been widely supported even among some advocates of abortion rights, harm large numbers of individuals and prevent some from getting the care they need.

“If liberal states and organizations are talking about reproductive justice, then that conversation needs to include the needs of young people, too,” said Coleman-Minahan. “They deserve abortion care as much as older people and are often left out of the conversation.”

FOR PROFIT HEALTHCARE 

Quality of treatment for lung cancer varies widely across US


Researchers identify measures to improve treatment quality, health outcomes

Peer-Reviewed Publication

WASHINGTON UNIVERSITY IN ST. LOUIS

Quality of treatment for lung cancer varies widely across US 

IMAGE: A NEW STUDY BY RESEARCHERS AT WASHINGTON UNIVERSITY SCHOOL OF MEDICINE IN ST. LOUIS FOUND THAT THE QUALITY OF CARE FOR LUNG CANCER IN THE U.S. VARIES WIDELY. THE FINDINGS SHOW THAT HIGH-QUALITY CARE IS ASSOCIATED WITH IMPROVED OVERALL SURVIVAL RATES AMONG PATIENTS WITH LUNG CANCER. PICTURED IS THE STUDY’S SENIOR AUTHOR, VARUN PURI, MD, A THORACIC SURGEON AND PROFESSOR OF SURGERY AT THE SCHOOL OF MEDICINE, DURING A SURGERY. view more 

CREDIT: TIM PARKER/WASHINGTON UNIVERSITY

Treatment for lung cancer is rapidly evolving, with new technologies and research-proven procedures. However, a study from Washington University School of Medicine in St. Louis found the quality of care for lung cancer in the U.S. varies widely, with significantly worse outcomes among patients whose surgeries fall short of established treatment guidelines.

To help close the gap in the quality of care, the researchers examined five surgical quality metrics based on guidelines established by the National Comprehensive Cancer Network and other cancer groups, and found that adherence to these quality metrics was associated with improved overall survival rates.

The study is published Jan. 18 in JAMA Surgery.

“It is crucial to have a solid understanding of what constitutes a high-quality lung cancer surgery,” said the study’s senior author, Varun Puri, MD, a Washington University thoracic surgeon and professor of surgery who treats patients at Siteman Cancer Center, based at Barnes-Jewish Hospital and Washington University. “Improving adherence to surgical quality measures is critical to optimize long-term outcomes among patients with early-stage lung cancer seeking treatment intended to cure their cancer.”

Lung cancer is the leading cause of cancer deaths in the United States and is the second most common type of cancer, with non-small cell lung cancer accounting for 84% of all lung cancer cases, according to the American Cancer Society.

The five recommended quality metrics identified by researchers include performing surgery in a timely manner, shortly after diagnosis; determining the appropriate amount of lung tissue to be surgically removed; sampling multiple lymph nodes to confirm the cancer is staged correctly and has not spread to the lymph nodes; using minimally invasive surgery to reduce postsurgical pain and accelerate the recovery process; and ensuring that no cancer is left within the body, also known as a positive margin.

“Ideally, these quality metrics should be met as frequently as possible in any lung cancer surgery,” Puri said. “However, as our data show, adherence to these metrics can be highly variable across the U.S.”

For the study, the researchers analyzed de-identified medical records in a database maintained by the U.S. Veterans Health Administration, the nation’s largest integrated health-care delivery system. The researchers examined information involving 9,628 patients with early-stage non-small cell lung cancer who underwent surgery from Oct. 1, 2006, through Sept. 31, 2016. The researchers developed a surgical quality score reflecting the association between the five metrics and overall survival.

The average age of the VA patients was 67.8 years. The patients were predominantly male and white; however, statistical modeling controlled for different ages, genders and races.

Researchers also studied adherence to quality metrics and overall survival rates among 107,674 nonveteran patients who were listed in the National Cancer Database as patients from 2010 to 2016.

The researchers found poor adherence to several quality measures, both within VA and civilian hospitals. For example, only about one-third of patients in both cohorts received adequate lymph node sampling, and only about 40% received minimally invasive surgery.

“Many patient- and tumor-specific factors can influence the apparent quality of surgical care for lung cancer,” said the study’s first author, Brendan Heiden, MD, a surgical resident and research fellow at Washington University. “Nevertheless, it is important to try to standardize and optimize adherence to quality measures whenever possible. Early-stage lung cancer treatments are rapidly evolving with the introduction of exciting new therapies. Central to these advances, however, is the foundational principle of performing high-quality, evidence-based surgery. As our study demonstrates, adherence to surgical quality metrics can have a disproportionate impact on patients with lung cancer receiving surgical treatment aimed at curing the cancer.”

The rich meteorology of Mars studied in detail from the Perseverance rover

The analysis of the Martian atmosphere made by the MEDA instrument aboard NASA's Perseverance rover has been published in the journal Nature Geoscience

Peer-Reviewed Publication

UNIVERSITY OF THE BASQUE COUNTRY

Temperature at the Jezero crater 

IMAGE: DAILY TEMPERATURE CYCLES AT THE JEZERO CRATER ON MARS MEASURED BY THE MEDA INSTRUMENT. view more 

CREDIT: UPV-EHU/CAB-INTA/ NASA/JPL-CALTECH/

Perseverance is a NASA autonomous vehicle that arrived at the Jezero Crater (the bed of an ancient, now dried-up lake on Mars) on 18 February 2021. The rover is equipped with seven novel, complex scientific instruments dedicated to exploring the planet's surface in search of signs of possible past life, collecting and depositing samples to be brought back to Earth, testing new technologies for use in human exploration, and studying the planet’s atmosphere in detail. With regard to the aim of studying the atmosphere, the MEDA (Mars Environmental Dynamics Analyzer) instrument has been obtaining novel results. MEDA’s lead researcher is José Antonio Rodríguez-Manfredi of the Centre for Astrobiology (CAB) in Madrid, and it has had the participation of a team from the UPV/EHU's Planetary Sciences Research Group. The instrument comprises a set of sensors that measure temperature, pressure, wind, humidity and properties of the dust that is always present in suspension in the Mars atmosphere.

Perseverance has now completed its investigation of the atmosphere throughout the first Martian year (which lasts approximately two Earth years). A preview of the results, which appears on the cover, is published today in the January issue of the journal Nature Geoscience. Specifically, the UPV/EHU team, formed by Agustín Sánchez-Lavega, Ricardo Hueso, Teresa del Río-Gaztelurrutia and the PhD student Asier Munguira, has led the study of the seasonal and daily cycles of temperature and pressure, as well as their significant variations on other time scales resulting from very different processes.

Throughout the seasons, the average air temperature at the Jezero Crater, located near the planet's equator, is around minus 55 degrees Celsius, but varies greatly between day and night, with typical differences of around 50 to 60 degrees. In the middle of the day, the heating of the surface generates turbulent movements in the air as a result of the rise and fall of air masses (convection) which cease in the evening, when the air settles.

Pressure sensors, on the other hand, show in detail the seasonal change of the tenuous Martian atmosphere produced by the melting and freezing of atmospheric carbon dioxide at the polar caps, as well as by a complex, variable daily cycle, modulated by thermal tides in the atmosphere. “The pressure and temperature of the Mars atmosphere oscillate with periods of the Martian solar day (somewhat longer than the Earth's, it averages at 24 hrs 39.5 min) and with their submultiples, following the daily cycle of sunshine greatly influenced by the amount of dust and the presence of clouds in the atmosphere,” says Agustín Sánchez-Lavega, professor at the Faculty of Engineering - Bilbao (EIB) and co-researcher on the Mars 2020 mission.

Both sensors are also detecting dynamic phenomena in the atmosphere that occur in the vicinity of the rover, for example, those produced by the passage of whirlwinds known as “dust devils” because of the dust they sometimes kick up, or the generation of gravity waves whose origin is not yet well understood. “The dust devils are more abundant at Jezero than elsewhere on Mars, and can be very large, forming whirlwinds more than 100 metres in diameter. With MEDA we have been able to characterise not only their general aspects (size and abundance) but also to unravel how these whirlwinds function,” says Ricardo Hueso, lecturer at the Faculty of Engineering - Bilbao (EIB).

MEDA has also detected the presence of storms thousands of kilometres away, very similar in origin to terrestrial storms, as shown by the images from orbiting satellites, and which move along the edge of the north polar cap, formed by the deposition of carbonic snow.

Within the rich variety of phenomena studied, MEDA has been able to characterise in detail the changes that have taken place in the atmosphere by one of the dreaded dust storms, such as the one that developed in early January 2022. Its passage over the rover led to abrupt changes in temperature and pressure accompanied by strong gusts of wind, which kicked up dust and hit the instruments, damaging one of the wind sensors.

“MEDA is providing high-precision, meteorological measurements enabling the Martian atmosphere to be characterised, for the first time, from local scales at distances of a few metres, as well as on the global scale of the planet by collecting information on what is happening thousands of kilometres away. All this will lead to a better understanding of the Martian climate and improve the predictive models we use,” says Sánchez-Lavega.

Stellar initial mass function varies with metallicity and age of stars

Peer-Reviewed Publication

CHINESE ACADEMY OF SCIENCES HEADQUARTERS

New research reveals that the mass of newly born stars varies with their metal abundances and their birth time 

IMAGE: NEW RESEARCH REVEALS THAT THE MASS OF NEWLY BORN STARS (YELLOW, ORANGE, AND RED CIRCLES STAND FOR STARS FROM HIGHER TO LOWER MASS) VARIES WITH THEIR METAL ABUNDANCES AND THEIR BIRTH TIME (INNER CIRCLE MEANS BORN EARLIER) view more 

CREDIT: WU KUN

In the vast and diverse Universe, the initial mass distribution at the birth of a new population of stars determines the fate of galaxies. This relationship is described by the Initial Mass Function (IMF). For more than half a century, astronomers have assumed that the IMF is a universal relationship, i.e., it is uniform throughout the Universe.

However, in recent years, some indications suggest that in some galaxies where star formation is particularly active, the IMF may be of a different form than is often assumed in the Milky Way. But to fully verify these results, astronomers will need to find more direct observational evidence in the Milky Way.

Now, based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also known as the Guo Shou Jing telescope), a research team led by Prof. LIU Chao from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) has found a crucial piece of direct evidence on how the IMF varies with different environments.

This study was published in Nature on Jan. 18.

"The IMF varies with levels of metal elements, and populations of stars born earlier in the Universe's history contain fewer low-mass stars than younger populations," said LI Jiadong, a Ph.D. student at NAOC and first author of the study.

Counting stars in a given volume is a direct and classical way to measure the IMF of low-mass (red dwarf) stars, whose mass distribution does not evolve with time; this approach is essentially independent of models or assumptions.

"Although many previous studies applied star counting to derive the IMF, two problems have not been solved. One is that only a small number of stars were counted in previous work. The second is that previous studies did not measure the metallicity of stars," said Prof. ZHANG Zhiyu, co-author of the study.

LAMOST has provided spectra that contain information about the chemical composition, temperature and luminosity of millions of stars, enabling the researchers to measure the metallicity of nearby red dwarf stars.

By selecting about 93,000 red dwarf stars in catalogues from both LAMOST and the Gaia survey, the researchers were able to group stars according to their metallicity and calculate the distribution of stellar mass in each group.

The study has revealed the variable abundance of low-mass stars in our galaxy, the Milky Way, and established a powerful benchmark for models of star formation. The findings may also affect the results of models of chemical enrichment of distant galaxies, as well as estimates of galaxy mass and the efficiency of planet formation.

"For instance, the total stellar mass of galaxies is often estimated by assuming that the IMF is invariant, but if the IMF is variable, this could change the total mass estimates of galaxies and potentially alter the field of Galactic astronomy," said Prof. LIU.

Prof. Pavel Kroupa, an authority on the IMF at the University of Bonn, Germany, commented on the results: "On the basis of a large ensemble of well-observed stars, the authors report that the IMF of late-type stars in the local Galactic disk is metallicity- and age-dependent. These results are highly important for addressing how universal the stellar IMF is and enable an in-depth understanding of the possible shifts in stellar populations that formed at different times and under different conditions in the Galaxy."