Tuesday, July 07, 2020

Study: Troubling connection between workplace pregnancy discrimination and health of mothers, babies

Researcher shares practical steps for managers to combat discrimination

BAYLOR UNIVERSITY

WACO, Texas (July 7, 2020) - Perceived pregnancy discrimination indirectly relates to increased levels of postpartum depressive symptoms for mothers and lower birth weights, lower gestational ages and increased numbers of doctor visits for babies, according to a management study led by Baylor University.

The study - "Examining the Effects of Perceived Pregnancy Discrimination on Mother and Baby Health" - is published in the Journal of Applied Psychology.

"Despite being illegal, pregnancy discrimination still takes place in the workplace," said lead author Kaylee Hackney, Ph.D., assistant professor of management in Baylor University's Hankamer School of Business. "Obviously, this is troublesome. Our research highlights the negative impact that perceived pregnancy discrimination can have on both the mother's and the baby's health."

The researchers surveyed 252 pregnant employees over the course of two studies. They measured perceived pregnancy discrimination, perceived stress, demographics and postpartum depressive symptoms. The second study included the measurements of the babies' health outcomes, including gestational age (number of weeks of pregnancy when the baby was delivered), Apgar score (heart rate, respiration, muscle tone, reflex response and color), birth weight and visits to the doctor.

Sample survey statements and questions used to measure perceived discrimination, perceived stress and postpartum depressive symptoms included: "Prejudice toward pregnant workers exists where I work," "In the last month, how often have you felt nervous or stressed?" and "I am so unhappy that I cry." Mothers also logged their babies' health outcomes.

"I think the biggest surprise from this research is that pregnancy discrimination not only negatively impacted the mother, but also negatively impacted the baby she was carrying while experiencing the discrimination," Hackney said. "This just shows the far-reaching implications of workplace discrimination and highlights the importance of addressing it."

More than 50,000 discrimination claims in a decade

The study noted that over the last decade, more than 50,000 pregnancy discrimination claims were filed with the Equal Employment Opportunity Commission and Fair Employment Practices Agencies in the United States.

Pregnancy discrimination is defined as unfavorable treatment of women at work due to pregnancy, childbirth or medical conditions related to pregnancy or childbirth, Hackney said. Pregnant women perceive discrimination when they experience subtly hostile behaviors such as social isolation, negative stereotyping and negative or rude interpersonal treatment.

Examples might include lower performance expectations, transferring the pregnant employee to less-desirable shifts or assignments or inappropriate jokes and intrusive comments.

Practical steps for managers

Given that pregnancy discrimination led to adverse health outcomes through increased stress, the researchers believe managers are in a unique position to provide the support that pregnant employees need to reduce stress.

Some steps managers might take include:

Providing flexible schedules
Keeping information channels open and the employee in the loop, specifically with regards to work-family benefits and expectations leading up to leave/returning from leave
Accommodating prenatal appointments
Helping to plan maternity leave arrangements
Normalizing breastfeeding in the workplace

"Overall, I would suggest that managers 1) strive to create a workplace culture where discrimination does not take place and 2) not make assumptions about what pregnant employees want," Hackney said. "The best approach would be to have an open dialogue with their employees about what types of support are needed and desired."

Healthcare partnerships

In addition, Hackney said the findings suggest that healthcare organizations may find opportunities to provide guidance and outreach to workplaces to help pregnant workers reduce stress via reduced pregnancy discrimination and enhanced work-family support for pregnant women.

Some steps may include training managers to be more family supportive and less biased against expectant mothers, she said.

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ABOUT THE STUDY

"Examining the Effects of Perceived Pregnancy Discrimination on Mother and Baby Health" is published in the Journal of Applied Psychology. Authors are Kaylee Hackney, Ph.D., assistant professor of management, Baylor University's Hankamer School of Business; Shanna R. Daniels, Ph.D., assistant professor of management, Florida State University; Samantha Paustian-Underdahl, Ph.D., assistant professor of management, Florida State University; Pamela Perrewé, the Robert O. Lawton Distinguished Professor and Haywood and Betty Taylor Eminent Scholar of Business Administration, Florida State University; Ashley Mandeville, Ph.D., assistant professor of management, Florida Gulf Coast University; and Asia Eaton, Ph.D., associate professor of Psychology, Florida International University.

ABOUT BAYLOR UNIVERSITY

Baylor University is a private Christian University and a nationally ranked research institution. The University provides a vibrant campus community for more than 18,000 students by blending interdisciplinary research with an international reputation for educational excellence and a faculty commitment to teaching and scholarship. Chartered in 1845 by the Republic of Texas through the efforts of Baptist pioneers, Baylor is the oldest continually operating University in Texas. Located in Waco, Baylor welcomes students from all 50 states and more than 90 countries to study a broad range of degrees among its 12 nationally recognized academic divisions.

ABOUT HANKAMER SCHOOL OF BUSINESS AT BAYLOR UNIVERSITY

At Baylor University's Hankamer School of Business, top-ranked programs combine rigorous classroom learning, hands-on experience in the real world, a solid foundation in Christian values and a global outlook. Making up approximately 25 percent of the University's total enrollment, undergraduate students choose from 16 major areas of study. Graduate students choose from full-time, executive or online MBA or other specialized master's programs, and Ph.D. programs in Information Systems, Entrepreneurship or Health Services Research. The Business School also has campuses located in Austin and Dallas, Texas. Visit baylor.edu/business for more information.

Time to get real on the power of positive thinking -- new study

Realists experience the highest long-term happiness

UNIVERSITY OF BATH

Volume 0%

VIDEO: DR CHRIS DAWSON, ASSOCIATE PROFESSOR IN BUSINESS ECONOMICS AT THE UNIVERSITY OF BATH'S SCHOOL OF MANAGEMENT DISCUSSES HIS RESEARCH SUGGESTING OPTIMISM IS NOT THE ROUTE TO LONG TERM HAPPINESS view more

CREDIT: UNIVERSITY OF BATH, UK

Positive thinking has long been extolled as the route to happiness, but it might be time to ditch the self-help books after a new study shows that realists enjoy a greater sense of long-term wellbeing than optimists.

Researchers from the University of Bath and London School of Economics and Political Science (LSE) studied people's financial expectations in life and compared them to actual outcomes over an 18-year period. They found that when it comes to the happiness stakes, overestimating outcomes was associated with lower wellbeing than setting realistic expectations.

The findings point to the benefits of making decisions based on accurate, unbiased assessments. They bring in to question the 'power of positive thinking' which frames optimism as a self-fulfilling prophecy, whereby believing in success delivers it, along with immediate happiness generated by picturing a positive future.

Negative thinking should not replace positive thinking though. Pessimists also fared badly compared to realists, undermining the view that low expectations limit disappointment and present a route to contentment.

Their numbers are dwarfed though by the number of people - estimated to be 80 percent of the population - who can be classed as unrealistic optimists. These people tend to overestimate the likelihood that good things will happen and underestimate the possibility of bad things. High expectations set them up for large doses of destructive disappointment.

"Plans based on inaccurate beliefs make for poor decisions and are bound to deliver worse outcomes than would rational, realistic beliefs, leading to lower well-being for both optimists and pessimists. Particularly prone to this are decisions on employment, savings and any choice involving risk and uncertainty," explains Dr Chris Dawson, Associate Professor in Business Economics in Bath's School of Management.

"I think for many people, research that shows you don't have to spend your days striving to think positively might come as a relief. We see that being realistic about your future and making sound decisions based on evidence can bring a sense of well-being, without having to immerse yourself in relentless positivity."

The results could also be due to counteracting emotions, say the researchers. For optimists, disappointment may eventually overwhelm the anticipatory feelings of expecting the best, so happiness starts to fall. For pessimists, the constant dread of expecting the worst may overtake the positive emotions from doing better than expected.

In the context of the Covid-19 crisis the researchers highlight that optimists and pessimists alike make decisions based on biased expectations: not only can this lead to bad decision making but also a failure to undertake suitable precautions to potential threats.

"Optimists will see themselves as less susceptible to the risk of Covid-19 than others and are therefore less likely to take appropriate precautionary measures. Pessimists, on the other hand, may be tempted to never leave their houses or send their children to school again. Neither strategy seems like a suitable recipe for well-being. Realists take measured risks based on our scientific understanding of the disease," said co-author Professor David de Meza from LSE's Department of Management.

Published in the American journal Personality & Social Psychology Bulletin the, findings are based on analysis from the British Household Panel Survey - a major UK longitudinal survey - tracking 1,600 individuals annually over 18 years.

To investigate whether optimists, pessimists or realists have the highest long-term well-being the researchers measured self-reported life satisfaction and psychological distress. Alongside this, they measured participants' finances and their tendency to have over- or under-estimated them.

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Neither an Optimist Nor a Pessimist Be: Mistaken Expectations Lower Well-Being is published at https://journals.sagepub.com/doi/full/10.1177/0146167220934577

Study: Interplay of impact, moral goals influences charitable giving to different causes

UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU

IMAGE: WITH THE RISE OF GLOBALIZATION, GEOGRAPHIC BORDERS ARE BECOMING LESS RELEVANT FOR MAKING CHARITABLE DONATIONS, WHICH MEANS NONPROFITS AND CHARITIES CAN MAKE MORE EFFECTIVE PITCHES TO DONORS BY EMPHASIZING HIGHER-LEVEL... view more

CREDIT: PHOTO BY GIES COLLEGE OF BUSINESS

CHAMPAIGN, Ill. -- Charitable giving is a nearly half-trillion-dollar sector of the U.S. economy, but what accounts for why some individuals, foundations and corporations give locally while others give to charities on the other side of the globe? According to a new paper co-written by a University of Illinois at Urbana-Champaign expert in consumer behavior and global marketing, the dynamic interplay between the accessibility of local impact versus more global goals can influence charitable behaviors between donors and recipients.

An appeal to morality can persuade people to make donations that benefit recipients halfway around the world - even though those same resources could be allocated to helping those with similar needs who live closer, said Carlos Torelli, a professor of business administration and the James F. Towey Faculty Fellow at Illinois.

"Although past research suggests that people are more likely to donate money to nearby causes to maximize the positive impact on their local community, donations to foreign causes are growing rapidly," he said. "With the rise of globalization, geographic borders are becoming less relevant for making charitable donations, which means nonprofits and charities can make more effective pitches to donors by emphasizing higher-level concepts such as morality and idealistic values."

Torelli and his co-authors conducted five studies to identify the conditions under which donors pledge higher amounts of money to recipients who are located spatially far away versus nearby recipients, and to rule out the possibility that the effect of spatial distance is driven by unequal economic conditions and, thus, differences in need between the two recipients.

"What we found is that people who donate money to causes that aren't local do so to feel more fulfilled, because it's something that's more aligned with their moral identity, which is the extent to which moral traits, goals and behaviors are important to one's self-concept or self-identity," said Torelli, also the executive director of Executive and Professional Education at the Gies College of Business. "We also found that this positive effect was more prevalent among people high in moral self-concept and was attenuated or even reversed among people low in moral self-concept."

The appeal to morality in requesting donations for distant recipients is "an entirely different framework" than for requesting donations to a local cause, which should emphasize the concrete, actionable impact of a monetary donation, Torelli said.

"For local or nearby causes, you really have to push the immediate impact aspect of it - how many people you can help, how much and how quickly your dollar can be put to work for individuals who are members of the community," he said. "The morality appeal, on the other hand, really has to tap into higher-level idealistic goals - clean water for everyone the alleviation of hunger, for example."

The paper's findings can help organizations increase the efficacy of marketing initiatives, Torelli said.

"The same cause can use different appeals depending on who they're targeting and where they are," he said. "If they're far away, then an appeal to morality is going to be more effective than an appeal to sheer numbers and impact."

The research also has implications for for-profit organizations engaging in corporate social-responsibility initiatives.

"Many large organizations are global and choose international charitable organizations to partner with, to align their social impact with their practices and beliefs," Torelli said. "Not only does this type of initiative have a social impact, it can also have a positive impact on employees of the organization. Our findings suggest that companies with corporate social-responsibility initiatives that help recipients in distant locations could benefit by focusing their communications on the higher-level goals that such initiatives are accomplishing instead of just touting their impact.

"Doing so might result in higher employee involvement with the charitable cause and higher employee satisfaction, particularly for employees who place a lot of importance on moral identity."

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Torelli's co-authors are Maria A. Rodas of the University of Southern California and Alison Jing Xu of the University of Minnesota.

The paper was published in the journal Organizational Behavior and Human Decision Processes.

Running in Tarahumara culture

Long distance runners

UNIVERSITY OF CHICAGO PRESS JOURNALS

IMAGE: IMAGE SHOWING RARÁMURI RUNNERS. view more

CREDIT: LIEBERMAN, DANIEL E.

"Running in Tarahumara (Rarámuri) Culture," just published in Current Anthropology (v61, no. 3 (June 2020): 356-379) studies the Tarahumara Native Americans of northern Mexico. For over a century, the Tarahumara have been famous for their long distance running traditions and abilities, with many accounts claiming they have superhuman athletic abilities that partly result from being uncontaminated by westernization. Now an international team of researchers (including a champion Tarahumara runner) combine their own observations with detailed interviews of elderly Tarahumara runners to dispel these stereotypical myths, which they term the "fallacy of the athletic savage." Lieberman and colleagues use accounts by Tarahumara runners to detail the various ways Tarahumara used to run for hours to hunt animals, and they describe how the Tarahumara still run traditional long distance races that, for men, involve chasing a small wooden ball and, for women, a hoop. While these many different kinds of running have important social dimensions, running is also a spiritually vital form of prayer for the Tarahumara. Further, contrary to the fallacy of the athletic savage, Tarahumara runners --both men and women-- struggle just as much as runners from other cultures to run long distances, and instead of being the natural "superathletes" that some journalists have claimed, they develop their endurance from regular hard work and other endurance physical activities such as lots of walking and dancing.

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Daniel E. Lieberman, Mickey Mahaffey, Silvino Cubesare Quimare, Nicholas B. Holowka, Ian J. Wallace, and Aaron L. Baggish, "Running in Tarahumara (Rarámuri) Culture: Persistence Hunting, Footracing, Dancing, Work, and the Fallacy of the Athletic Savage," Current Anthropology 61, no. 3 (June 2020): 356-379.

we are knee deep in the first wave of coronavirus pandemic

dr. fauci

nih conference 7/5/2020

Global success for Canadian companies depends on prior R&D investment, receptiveness to new learning

UNIVERSITY OF TORONTO, ROTMAN SCHOOL OF MANAGEMENT

IMAGE: WALID HEJAZI IS AN ASSOCIATE PROFESSOR OF ECONOMIC ANALYSIS AND POLICY AT THE UNIVERSITY OF TORONTO'S ROTMAN SCHOOL OF MANAGEMENT. HE HAS RESEARCHED, ADVISED, AND TESTIFIED EXTENSIVELY ON GLOBAL COMPETITIVENESS,... view more

CREDIT: ROTMAN SCHOOL

Global success for Canadian companies depends on prior R&D investment, receptiveness to new learning, shows new study.

Toronto - Canadian companies that go international are known to be more productive and successful than those that don't.

New research has quantified the reasons why. It shows that about 80 percent of global companies' productivity is due to what they did before going abroad - namely, making themselves more competitive, including by investing in research and development. The other 20 percent is due to what companies learned from their exposure to international markets.

The findings show that going global on its own is no guarantee of higher productivity, says lead researcher Walid Hejazi.

"A company has to be prepared, it has to be much, much better in Canada before it can be successful abroad," says Prof. Hejazi, an associate professor of economic analysis and policy at the University of Toronto's Rotman School of Management and an expert on Canadian companies' global competitiveness.

That preparation is required because a company needs processes and technologies in place that enable it to absorb and integrate what it learns once it has entered a foreign market.

Companies that have not yet reached a certain productivity threshold can still benefit from going global, however. The researchers found that the minimum required level of productivity represented a range, rather than being a fixed number.

"If a company is prepared well enough, it can still go abroad and then through learning, rise above the threshold that it needs," says Prof. Hejazi. Overall, global Canadian companies were found to be 60 to 76 percent more productive than those that stayed home. About 20 percent of their investment moved through offshore financial centres.

Companies have the best chance of learning when they locate to countries with a similar language - aiding in communication -- and with strong legal and government institutions, the researchers found.

If that's not the case, companies can still position themselves to take advantage of foreign market learning opportunities by assembling a culturally literate management team, with experience in the new market, says Prof. Hejazi.

The findings are drawn from advanced statistical analyses that Prof. Hejazi and his co-researchers conducted on confidential data from Statistics Canada about every Canadian company between 2000 and 2014. The research responds to the Canadian government's interest in better understanding the ingredients for international success among Canadian companies.

Given that Canadian companies still lag many other countries for R&D spending, the study's results underscore the importance of government and Canadian business working together to promote innovation and advancement to the global stage, says Prof. Hejazi.

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The study is forthcoming in the Journal of International Business Studies. It is co-authored by Jianmin Tang of Innovation, Science and Economic Development Canada and Weimin Wang, from Statistics Canada.

The Rotman School of Management is part of the University of Toronto, a global centre of research and teaching excellence at the heart of Canada's commercial capital. Rotman is a catalyst for transformative learning, insights and public engagement, bringing together diverse views and initiatives around a defining purpose: to create value for business and society. For more information, visit http://www.rotman.utoronto.ca

Study: Dying stars breathe life into Earth

JOHNS HOPKINS UNIVERSITY

IMAGE: NGC 7789, ALSO KNOWN AS CAROLINE'S ROSE, IS AN OLD OPEN STAR CLUSTER OF THE MILKY WAY, WHICH LIES ABOUT 8,000 LIGHT-YEARS AWAY TOWARD THE CONSTELLATION CASSIOPEIA. IT HOSTS... view more

CREDIT: GUILLAUME SEIGNEURET AND NASA

As dying stars take their final few breaths of life, they gently sprinkle their ashes into the cosmos through the magnificent planetary nebulae. These ashes, spread via stellar winds, are enriched with many different chemical elements, including carbon.

Findings from a study published today in Nature Astronomy show that the final breaths of these dying stars, called white dwarfs, shed light on carbon's origin in the Milky Way.

"The findings pose new, stringent constraints on how and when carbon was produced by stars of our galaxy, ending up within the raw material from which the Sun and its planetary system were formed 4.6 billion years ago," says Jeffrey Cummings, an Associate Research Scientist in the Johns Hopkins University's Department of Physics & Astronomy and an author on the paper.

The origin of carbon, an element essential to life on Earth, in the Milky Way galaxy is still debated among astrophysicists: some are in favor of low-mass stars that blew off their carbon-rich envelopes by stellar winds became white dwarfs, and others place the major site of carbon's synthesis in the winds of massive stars that eventually exploded as supernovae.

Using data from the Keck Observatory near the summit of Mauna Kea volcano in Hawaii collected between August and September 2018, the researchers analyzed white dwarfs belonging to the Milky Way's open star clusters. Open star clusters are groups of up to a few thousand stars held together by mutual gravitational attraction.

From this analysis, the research team measured the white dwarfs' masses, and using the theory of stellar evolution, also calculated their masses at birth.

The connection between the birth masses to the final white dwarf masses is called the initial-final mass relation, a fundamental diagnostic in astrophysics that contains the entire life cycles of stars. Previous research always found an increasing linear relationship: the more massive the star at birth, the more massive the white dwarf left at its death.

But when Cummings and his colleagues calculated the initial-final mass relation, they were shocked to find that the white dwarfs from this group of open clusters had larger masses than astrophysicists previously believed. This discovery, they realized, broke the linear trend other studies always found. In other words, stars born roughly 1 billion years ago in the Milky Way didn't produce white dwarfs of about 0.60-0.65 solar masses, as it was commonly thought, but they died leaving behind more massive remnants of about 0.7 - 0.75 solar masses.

The researchers say that this kink in the trend explains how carbon from low-mass stars made its way into the Milky Way. In the last phases of their lives, stars twice as massive as the Milky Way's Sun produced new carbon atoms in their hot interiors, transported them to the surface and finally spread them into the surrounding interstellar environment through gentle stellar winds. The research team's stellar models indicate that the stripping of the carbon-rich outer mantle occurred slowly enough to allow the central cores of these stars, the future white dwarfs, to grow considerably in mass.

The team calculated that stars had to be at least 1.5 solar masses to spread its carbon-rich ashes upon death.

The findings, according to Paola Marigo, a Professor of Physics and Astronomy at the University of Padova and the study's first author, helps scientists understand the properties of galaxies in the universe. By combining the theories of cosmology and stellar evolution, the researchers expect that bright carbon-rich stars close to their death, like the progenitors of the white dwarfs analyzed in this study, are presently contributing to the light emitted by very distant galaxies. This light, which carries the signature of newly produced carbon, is routinely collected by the large telescopes from space and Earth to probe the evolution of cosmic structures. Therefore, this new understanding of how carbon is synthesized in stars also means having a more reliable interpreter of the light from the far universe.

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This study was funded by the European Research Council Consolidator Grant (project STARKEY, 615604) and the European Union's Horizon 2020 research and innovation program (677706-WD3D).

Other authors on this study include Jason Kalirai and Sihao Cheng of the Johns Hopkins University; Jason Lee Curtis of the American Museum of Natural History; Yang Chen and Bernhard Aringer of the University of Padova; Pier-Emmanuel Tremblay of the University of Warwick; Enrico Ramirez-Ruiz of the University of California, Santa Cruz; Pierre Bergeron of the Université de Montréal; Sara Bladh of Uppsala University; Alessandro Bressan of the International School for Advanced Studies; Léo Girardi of the Astronomical Observatory of Padova-INAF; Giada Pastorelli of the Space Telescope Science Institute; and Michele Trabucchi and Piero Dal Tio of the University of Geneva.

Joni Mitchell – Woodstock
I came upon a child of God
He was walking along the road
And I asked him, where are you going
And this he told me
I'm going on down to Yasgur's farm
I'm going to join in a rock 'n' roll band
I'm going to camp out on the land
I'm going to try an' get my soul free
We are stardust
We are golden
And we've got to get ourselves
Back to the garden

Then can I walk beside you
I have come here to lose the smog
And I feel to be a cog in something turning
Well maybe it is just the time of year
Or maybe it's the time of man
I don't know who l am
But you know life is for learning
We are stardust
We are golden
And we've got to get ourselves
Back to the garden

By the time we got to Woodstock
We were half a million strong
And everywhere there was song and celebration
And I drnation
eamed I saw the bombers
Riding shotgun in the sky
And they were turning into butterflies
Above our We are stardust
Billion year old carbon
We are golden
Caught in the devil's bargain
And we've got to get ourselves
Back to the garden

White dwarfs reveal new insights into the origin of carbon in the universe

UNIVERSITY OF CALIFORNIA - SANTA CRUZ

A new analysis of white dwarf stars supports their role as a key source of carbon, an element crucial to all life, in the Milky Way and other galaxies.

Approximately 90 percent of all stars end their lives as white dwarfs, very dense stellar remnants that gradually cool and dim over billions of years. With their final few breaths before they collapse, however, these stars leave an important legacy, spreading their ashes into the surrounding space through stellar winds enriched with chemical elements, including carbon, newly synthesized in the star's deep interior during the last stages before its death.

Every carbon atom in the universe was created by stars, through the fusion of three helium nuclei. But astrophysicists still debate which types of stars are the primary source of the carbon in our own galaxy, the Milky Way. Some studies favor low-mass stars that blew off their envelopes in stellar winds and became white dwarfs, while others favor massive stars that eventually exploded as supernovae.

In the new study, published July 6 in Nature Astronomy, an international team of astronomers discovered and analyzed white dwarfs in open star clusters in the Milky Way, and their findings help shed light on the origin of the carbon in our galaxy. Open star clusters are groups of up to a few thousand stars, formed from the same giant molecular cloud and roughly the same age, and held together by mutual gravitational attraction. The study was based on astronomical observations conducted in 2018 at the W. M. Keck Observatory in Hawaii and led by coauthor Enrico Ramirez-Ruiz, professor of astronomy and astrophysics at UC Santa Cruz.

"From the analysis of the observed Keck spectra, it was possible to measure the masses of the white dwarfs. Using the theory of stellar evolution, we were able to trace back to the progenitor stars and derive their masses at birth," Ramirez-Ruiz explained.

The relationship between the initial masses of stars and their final masses as white dwarfs is known as the initial-final mass relation, a fundamental diagnostic in astrophysics that integrates information from the entire life cycles of stars, linking birth to death. In general, the more massive the star at birth, the more massive the white dwarf left at its death, and this trend has been supported on both observational and theoretical grounds.

But analysis of the newly discovered white dwarfs in old open clusters gave a surprising result: the masses of these white dwarfs were notably larger than expected, putting a "kink" in the initial-final mass relation for stars with initial masses in a certain range.

"Our study interprets this kink in the initial-final mass relationship as the signature of the synthesis of carbon made by low-mass stars in the Milky Way," said lead author Paola Marigo at the University of Padua in Italy.

In the last phases of their lives, stars twice as massive as our Sun produced new carbon atoms in their hot interiors, transported them to the surface, and finally spread them into the interstellar medium through gentle stellar winds. The team's detailed stellar models indicate that the stripping of the carbon-rich outer mantle occurred slowly enough to allow the central cores of these stars, the future white dwarfs, to grow appreciably in mass.

Analyzing the initial-final mass relation around the kink, the researchers concluded that stars bigger than 2 solar masses also contributed to the galactic enrichment of carbon, while stars of less than 1.5 solar masses did not. In other words, 1.5 solar masses represents the minimum mass for a star to spread carbon-enriched ashes upon its death.

These findings place stringent constraints on how and when carbon, the element essential to life on Earth, was produced by the stars of our galaxy, eventually ending up trapped in the raw material from which the Sun and its planetary system were formed 4.6 billion years ago.

"Now we know that the carbon came from stars with a birth mass of not less than roughly 1.5 solar masses," said Marigo.

Coauthor Pier-Emmanuel Tremblay at University of Warwick said, "One of most exciting aspects of this research is that it impacts the age of known white dwarfs, which are essential cosmic probes to understand the formation history of the Milky Way. The initial-to-final mass relation is also what sets the lower mass limit for supernovae, the gigantic explosions seen at large distances and that are really important to understand the nature of the universe."

By combining the theories of cosmology and stellar evolution, the researchers concluded that bright carbon-rich stars close to their death, quite similar to the progenitors of the white dwarfs analyzed in this study, are presently contributing to a vast amount of the light emitted by very distant galaxies. This light, carrying the signature of newly produced carbon, is routinely collected by large telescopes to probe the evolution of cosmic structures. A reliable interpretation of this light depends on understanding the synthesis of carbon in stars.

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In addition to Marigo, Tremblay, and Ramirez-Ruiz, the coauthors of the paper include scientists at Johns Hopkins University, American Museum of Natural History in New York, Columbia University, Space Telescope Science Institute, University of Warwick, University of Montreal, University of Uppsala, International School for Advanced Studies in Trieste, Italian National Institute for Astrophysics, and the University of Geneva. This research was supported by the European Union through an ERC Consolidator Grant and the DNRF through a Niels Bohr Professorship.

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