Sunday, November 20, 2022

Power and Prediction: The Disruptive Economics of Artificial Intelligence. Book explains the ways AI will impact us

Book Announcement

UNIVERSITY OF TORONTO, ROTMAN SCHOOL OF MANAGEMENT

Power and Prediction: The Disruptive Economics of Artificial Intelligence 

IMAGE: WHEN ELECTRICITY WAS INTRODUCED IN THE 1880S, NOT EVERYONE IMMEDIATELY SWITCHED FROM CANDLES TO LIGHTBULBS, BUT THERE WAS A RAPID SHIFT IN SUBSEQUENT YEARS. THE SAME IS TRUE FOR ARTIFICIAL INTELLIGENCE, WARN AJAY AGRAWAL, JOSHUA GANS, AND AVI GOLDFARB, ECONOMISTS AND PROFESSORS AT UNIVERSITY OF TORONTO'S ROTMAN SCHOOL OF MANAGEMENT. IN THEIR BESTSELLING BOOK, PREDICTION MACHINES, THEY FOCUSED ON THE ECONOMIC BENEFITS OF AI FOR CHEAPER, FASTER, BETTER PREDICTIONS. IN POWER AND PREDICTION: THE DISRUPTIVE ECONOMICS OF ARTIFICIAL INTELLIGENCE, PUBLISHED BY HARVARD BUSINESS REVIEW PRESS, THEY TURN THEIR ATTENTION TO EXPLAINING THE WAYS THIS TRANSFORMATIVE TECHNOLOGY WILL IMPACT US AND HOW TO IDENTIFY THE THREATS AND OPPORTUNITIES. view more 

CREDIT: HARVARD BUSINESS REVIEW PRESS

Toronto – When electricity was introduced in the 1880s, not everyone immediately switched from candles to lightbulbs, but there was a rapid shift in subsequent years. The same is true for artificial intelligence, warn Ajay Agrawal, Joshua Gans, and Avi Goldfarb, economists and professors at University of Toronto's Rotman School of Management. In their bestselling book, Prediction Machines, they focused on the economic benefits of AI for cheaper, faster, better predictions. In Power and Prediction: The Disruptive Economics of Artificial Intelligence, published by Harvard Business Review Press, they turn their attention to explaining the ways this transformative technology will impact us and how to identify the threats and opportunities.

They introduce several key concepts:

The Between Times – We have entered a unique moment in history—after witnessing the power of AI and before its widespread adoption, the authors argue. Some industries have been quick to embrace AI, while others are slower. The reason for this uneven approach is because we have not fully considered the effect of the larger systems in which we operate, the authors argue, and different solution types provide different opportunities to gain market share.

 

The AI bullwhip – The challenge is building reliable AI systems to enable new ways of serving people. However, the authors caution, the AI bullwhip happens when it improves the quality of one decision but harms others in the system by lowering reliability for other decisions. For example, more accurate forecasting at a restaurant for vegetables may mean wildly fluctuating orders for farmers used to consistency, which throws off their harvest. Like a bullwhip, a small change in one place can lead to a big crack elsewhere. Such unforeseen consequences can be protected by designing the optimal balance of coordination where possible and building a wall of modularity where necessary.

When rules should become unglued – Rules are good to help reduce error and ensure reliability. However, some rules have been created to mask decisions in an organization that have a degree of uncertainty. “Ungluing” a decision from the related policies and procedures enables AI to make predictions. However, changing one task is not worth implementing an expensive AI system. The real value is in combining multiple decisions. In some cases, this means newer companies will have an advantage over established corporations.

Power and disruption  As old systems are displaced, there is a shift in economic power as the reward for innovation. AI gives an advantage to early adopters. This flywheel explains why some in the venture capital community are investing so aggressively in seemingly nascent AI projects. Some assume AI will provide valuable “insights” but the authors argue this is the wrong way to think. Instead, they say AI only has value if it leads to better decision-making. Others worry that machines will hold all the power. However, the authors show that humans still control the decisions being made. The challenge is that the humans and organizations that control decision-making can change.

Bias and reducing discrimination  Another big worry is bias. However, the authors argue that AI can actually detect discrimination and reduce it. But, it requires overcoming the legal and regulatory challenges of a world designed for humans unaided by algorithms as well as navigating resistance from those who benefit from bias.

AI is already beginning to have an impact on decision making and the power balance within organizations. Insightful and provocative, Power and Prediction shows how this will happen.

About the Authors

Ajay Agrawal is Professor of Strategic Management and Geoffrey Taber Chair in Entrepreneurship and Innovation at the University of Toronto's Rotman School of Management. He is founder of the Creative Destruction Lab, cofounder of Next 36 and Next AI, and cofounder of Sanctuary, an AI/robotics company. Ajay conducts research on the economics of innovation and is a research associate at the National Bureau of Economic Research and faculty affiliate at the Vector Institute for Artificial Intelligence.

Joshua Gans is the Jeffrey S. Skoll Chair of Technical Innovation and Entrepreneurship and Professor of Strategic Management at Toronto's Rotman School of Management. He is Chief Economist of the Creative Destruction Lab, department editor (Strategy) at Management Science, and cofounder and managing director of Core Economic Research. Joshua has published numerous books on innovation, disruption, entrepreneurship, and most recently, pandemic economics. He is a research associate at the National Bureau of Economic Research, a research affiliate at MIT, a senior academic fellow at the e61 Institute, a distinguished fellow of the Luohan Academy, and a fellow of the Academy of Social Sciences in Australia.

Avi Goldfarb is the Rotman Chair in AI and Healthcare and Professor of Marketing at Toronto's Rotman School of Management. Avi is also Chief Data Scientist at the Creative Destruction Lab, a fellow at Behavioral Economics in Action at Rotman, a faculty affiliate at the Vector Institute for Artificial Intelligence, and a research associate at the National Bureau of Economic Research. A former senior editor at Marketing Science, Avi conducts research on privacy and the economics of technology.

The book will be launched at the Rotman School during a hybrid event on November 23 and further information on the book is online.

Bringing together high-impact faculty research and thought leadership on one searchable platform, the new Rotman Insights Hub offers articles, podcasts, opinions, books and videos representing the latest in management thinking and providing insights into the key issues facing business and society. Visit www.rotman.utoronto.ca/insightshub.

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 www.rotman.utoronto.ca  

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For more information: 

Ken McGuffin 

Manager, Media Relations 

Rotman School of Management 

University of Toronto 

E-mail:mcguffin@rotman.utoronto.ca 


Study shows how to boost early intervention for climate-related health risks


Peer-Reviewed Publication

DUKE UNIVERSITY

Engaging with local leaders 

IMAGE: DUKE UNIVERSITY PROFESSOR WILLIAM PAN MEETS WITH LEADERS OF A LOCAL COMMUNITY IN PERU TO DISCUSS A NEW EARLY WARNING SYSTEM HE’S DEVELOPED TO PREDICT AND HELP PREVENT MALARIA OUTBREAKS. view more 

CREDIT: DUKE UNIVERSITY

DURHAM, N.C.—Being able to predict where and when extreme weather and other environmental impacts of climate change will increase the risk of infectious disease outbreaks can help public health officials respond earlier and more effectively to control the spread and reduce its toll.

In fact, early warning systems designed to do just this have been developed in recent years to help control outbreaks of malaria, dengue fever and other diseases in parts of the Tropics. But their implementation has been undercut by funding uncertainties, overburdened local health systems, insufficient training for local health technicians, and a lack of buy-in from decision makers in government.

An analysis by an international team of researchers from 15 institutions evaluates these barriers to implementation and proposes new ways forward. The team published its recommendations Nov. 9 in The Lancet Planetary Health.

One key, the researchers say, is early engagement with crucial decision makers.

“We looked at five case studies and most of the barriers we identified likely could have been resolved by getting policymakers and community leaders on board right from the start,” said William Pan, the Elizabeth Brooks Reid and Whitelaw Reid Associate Professor of Population Studies at Duke University, who was co-lead author of the analysis.

In the case studies, scientists often placed a higher initial priority on getting their monitoring systems, disease-control protocols and local partners in place before turning their attention to briefing national or regional policymakers about it. In hindsight, the problem with this approach, Pan said, is that the local partners who were supposed to take over running the system once it was set up were not necessarily the government decision makers with the authority to commit ongoing financial or political support for it.

“You need to engage with these key decisions makers immediately so they understand what the benefits of the system will be and buy into it,” he said. Without this support, scaling up the system to a regional or national level can become an insurmountable challenge.

Training local health providers and technicians in environmental science also needs to be an immediate priority.

Local health systems, especially in poor or remote regions, are typically stretched thin and the people who do on-the-ground disease surveillance often have limited training in climate science or environmental epidemiology, Pan said. They’re trained in medicine or public health but not in how climate-sensitive environmental conditions such as extreme heat, drought, or flooding can drive disease outbreaks. So, they don’t know what to look for, how to project future impacts, or how or when to adjust their disease-control interventions in anticipation of them, he said.

“There’s currently no place in the world that has an early warning system for infectious diseases that integrates climate and environmental data with disease surveillance data,” Pan said. “Policymakers just haven’t picked up on it yet, even though it is what science tells us we need to be doing. It’s like trying to bake a cake with only half the ingredients.”

In the new paper, he and his coauthors use knowledge and tools from the emerging field of implementation science to propose a four-step, science-based framework for overcoming such barriers and enhancing the success of early warning systems.

First, you need to understand and anticipate potential barriers. Second, you need to engage key stakeholders at the outset and co-create the system with them. Third, you need to identify promising strategies to overcome barriers and test how they work in pilot studies under various conditions, using both quantitative data and qualitative measures, such as stakeholder interviews, to inform your analysis. Fourth, after implementing the strategies, you need to measure the outcomes of their implementation across a broad range of considerations, including acceptability, feasibility, sustainability and cost-effectiveness.

The new analysis is based on case studies of early warning systems for climate-related disease outbreaks or public health risks that have been recently developed in Peru, Barbados, Ethiopia, India, and the Federated States of Micronesia and the Marshall Islands.

Pan holds faculty appoints at Duke’s Nicholas School of the Environment and the Duke Global Health Institute. He co-led the new analysis with Gila Neta of the National Cancer Institute, part of the National Institutes of Health.

The paper was co-authored by researchers from the University of Washington; the Pan American Health Organization; the National Institute of Environmental Health Sciences; the Barcelona Supercomputing Center; the Catalan Institution for Research and Advanced Studies; the London School of Hygiene and Tropical Medicine; the University of Florida; the Inter-American Institute for Global Change Research; the Pacific Island Health Officers Association; the Energy and Resources Institute of New Delhi, India; the University of Oklahoma; the Barbados Ministry of Health and Wellness; and the University of Pittsburgh School of Public Health.

The team’s analysis was conducted with no new external funding.

CITATION: “Advancing Climate Change Health Adaption Through Implementation Science,” Gila Neta, William Pan, Kristie Ebi, Daniel F. Buss, Trisha Castranio, Rachel Lowe, Sadie J. Ryan, Ann M. Stewart-Ibarra, Limb K. Hapairai, Meena Sehgal, Michael C. Wimberly, Leslie Rollock, Maureen Lichtveld and John Balbus; The Lancet Planetary Health, Nov. 9, 2022. DOI: https://doi.org/10.1016/S2542-5196(22)00199-1

 

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New discoveries could improve cheese production and safety, lead to novel cheeses

Peer-Reviewed Publication

AMERICAN SOCIETY FOR MICROBIOLOGY

Washington, D.C. – November 15, 2022 – New research shows that the flavoring of various soft cheeses is due in part to the bacteria that colonize them during the ripening process. The research is published in Microbiology Spectrum, a journal of the American Society for Microbiology.

 

As cheese ages, beneficial bacteria degrade proteins and lipids (from milk fat) and produce the molecules responsible for characteristic aromas of ripening cheeses. (1) The diversity of “non-starter” bacteria, which spontaneously develop during ripening and form flavor compounds, is the key factor for developing the characteristics of cheese.

 

The role of microorganisms in flavor formation had not been fully understood, “due to the diversity of cheese varieties and the complexity of cheese microbial consortia,” said corresponding author Morio Ishikawa, Ph.D., a professor at the Department of Fermentation Science, Faculty of Applied Bioscience at the Tokyo University of Agriculture in Japan.

 

In the study, the investigators presented an approach to identifying and examining certain bacteria known to be involved in cheese production, including 3 phyla of bacteria, Firmicutes, which are lactic acid bacteria, and Actinobacteria and Proteobacteria, which produce characteristic flavors in certain cheeses. By comparing bacteria from across the 3 phyla to other known flavor-producing bacteria in a cheese ripening test, the researchers showed a relationship between specific microbes and flavor.

 

Ishikawa and his collaborators had used statistical analysis to reveal relationships between bacterial types and the various volatile flavor-producing organic compounds that each produces in surface-mold ripened cheeses. To test that relationship of specific microbes to flavor, they then selected non-starter bacteria of taxa that were strongly correlated with specific volatile compounds and flavors, and performed cheese-ripening tests. These tests showed that the bacteria from the correlational research were in fact responsible for the flavors of the cheeses.

 

Additionally, this research could provide a scientific basis for improving the safety and quality of cheese. “By isolating and investigating microorganisms involved in flavor formation as targets, rather than blindly examining them, we will be able to scientifically evaluate the safety of these microorganisms. At the same time, it may be possible to construct a cheese production method that uses only those microorganisms that play a major role in flavor production,” said Ishikawa.

 

“The comprehensive insights into the complex associations between microbiota and flavor improve our systematic understanding of mechanism of cheese flavor production,” said Ishikawa. The new research will not only provide a scientific basis for the traditional method of cheese production, but might also enable the creation of novel cheeses.

1. per Ishikawa, little or no lactose remains in cheese during ripening.

EPA grant to Wayne State University to evaluate chemical mixture health risks


Grant and Award Announcement

WAYNE STATE UNIVERSITY - OFFICE OF THE VICE PRESIDENT FOR RESEARCH

DETROIT – There are hidden metabolic health impacts in things that most people encounter every day.

From surface cleaners to silicone wristbands, from fracking fluids to wastewater — even household dust — these diverse environmental mixtures have a potential to disrupt human health.

Christopher Kassotis, Ph.D., an assistant professor in the Wayne State University School of Medicine’s Department of Pharmacology and Institute of Environmental Health Sciences, has received a grant to take a deeper dive into evaluating environmental mixtures.

“Anything we know about chemical toxicity is based on testing that individual chemical, but we are never exposed to just one single chemical alone,” Kassotis said. “Humans are regularly exposed to hundreds or thousands of chemicals every day. Our regulatory system completely ignores this, in part due to difficulties sorting out how to examine mixtures and predict effects.”

Thanks to a $598,487 grant from the U.S. Environmental Protection Agency (EPA), Kassotis will develop and evaluate methods and approaches to understanding human health risks that may result from exposure to chemical mixtures in the environment.

According to the EPA, toxicology studies have traditionally focused on the effects of single chemicals on human health. However, people are continually exposed to mixtures of numerous chemicals present in the environment, including in the air, water, soil, food and household products. These chemical mixtures include polyfluoroalkyl substances (PFAS), often thought of as “everywhere chemicals” since they have become so common in everyday products. Other well-characterized mixtures include phthalates, polycyclic aromatic hydrocarbons (PAHs) and disinfection byproducts (DBPs).

There is a need to assess the toxicity of these chemical mixtures and understand how their combined effects on human health and the environment differ from what is known about individual chemicals.

Kassotis and his research team use three laboratory-defined chemical mixtures of increasing complexity to tease apart when available mixture models succeed or fail in accurately predicting metabolic health outcomes in both cell and zebrafish models and better define the strengths and limitations of these models for risk assessments. They will use household dust samples to develop a receptor bioactivity component model to predict adipogenic health outcomes. Through their dust extract testing, WSU researchers expect to support a new method of mixture risk assessments

“Our study is designed to provide a more concrete footing for chemical mixture assessments, a better understanding of where the available mixture models succeed and fail in predicting toxicity,” he said. “In short, I'm hoping that these experiments will help shift the regulatory structure toward inclusion of more considerations of mixture exposures to better protect public health. We need to have a better understanding of how exposure to a single chemical varies with ongoing exposures to hundreds of other chemicals.

“If I had to try to distill it into a simple statement, I'm hoping to improve chemical risk assessment models to account for everyday exposures to hundreds of different chemicals and as a result lead to better protection of human health.”

Learn more about Kassotis and his research projects at his webpage.

The project number for this EPA award is R840459.

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About Wayne State University

Wayne State University is one of the nation’s pre-eminent public research universities in an urban setting. Through its multidisciplinary approach to research and education, and its ongoing collaboration with government, industry and other institutions, the university seeks to enhance economic growth and improve the quality of life in the city of Detroit, state of Michigan and throughout the world. For more information about research at Wayne State University, visit research.wayne.edu.

Ray of hope? One place where reef manta rays are thriving

In a rare piece of good news in the marine world, scientists have found one place where reef manta rays are thriving

Peer-Reviewed Publication

UNIVERSITY OF AUCKLAND

Reef manta rays 

IMAGE: REEF MANTA RAYS FEEDING EN MASSE IN RAJA AMPAT. view more 

CREDIT: EDY SETYAWAN, WAIPAPA TAUMATA RAU, UNIVERSITY OF AUCKLAND.

In a rare piece of good news in the marine world, scientists have found one place where reef manta rays are thriving.

Over a decade, populations increased significantly in Raja Ampat archipelago in Indonesia, highlighting the importance of long-term conservation and management measures such as well-enforced Marine Protected Areas (MPAs) and fisheries regulations, says researcher Edy Setyawan, of the University of Auckland’s Institute of Marine Science.

It is the first published evidence of reef manta ray populations increasing anywhere in the world, he says. “Despite the global decline in oceanic sharks and rays because of overfishing over the past 50 years, the reef manta rays in Raja Ampat have been recovering and thriving,” Setyawan says.

The scientist and his colleagues studied reef manta rays (Mobula alfredi) in two of Raja Ampat’s largest MPAs, Dampier Strait and South East Misool. They used sightings of rays, each individually identified by photograph, to assess population dynamics from 2009 to 2019. In Dampier Strait, the estimated population increased to 317, an annual compound gain of 3.9 percent, while South East Misool’s estimated gain to 511 was 10.7 percent on the same basis.

The increased population sizes resulted from high survival rates (up to 93 percent of individuals in each group survived each year) and high rates of recruitment (typically groups got a 20 percent annual boost from new members). While conservation measures substantially reduced fishing pressures, another reason for the populations thriving was the El Niño Southern Oscillation climate cycle, which boosted plankton numbers. That lead to larger and more frequent aggregations of the manta rays for feeding, which in turn provided more opportunities for mating.

A watch-list for threatened species, the International Union for Conservation of Nature’s “Red List,” lists reef manta ray as a “vulnerable” species with declining populations throughout their range in the Indo-Pacific, based on an assessment in 2018.

Today, an estimated of 16,000 to 18,000 of the creatures may survive, with the Maldives hosting the biggest number, at least 5,000 individuals, followed by Indonesia with at least 3,500. “Unfortunately, reef manta rays are generally in decline, as in Mozambique where they have been continuously caught in targeted fisheries, or just holding steady, as in Australia and the Maldives,” says Setyawan.

Around the world, more well-enforced MPAs are needed to protect the critical habitats of the creatures, along with strong commitments from governments to protect the species, and fishing gear restrictions such as bans on gillnets and longlines, he says. Manta rays are known for their intelligence, graceful swimming and traits such as somersault feeding, a technique for continuing to move while staying in the same spot to gorge on plankton or krill. Manta rays need to keep moving to stay alive.

The reef manta ray has a wingspan of up to five metres. This slow-growing species starts to mature at nine to 13 years of age (male) and 13 to 17 years of age (female). A mature female gives birth to only one pup every two to six years, after 12 to 13 months of pregnancy. Late maturation and low fecundity make the species especially vulnerable to population declines.

The research, published in Frontiers of Marine Science, was carried out with the help of researchers from the Raja Ampat MPA management authority, Konservasi Indonesia, Conservation International Aotearoa and Waipapa Taumata Rau, University of Auckland. “Since the study ended, the reef manta rays seem to be doing well and the populations continue to grow,” says Setyawan. “Large feeding aggregations have often been seen and reported. In the past three years, we have identified more than 300 new manta rays. Not to mention the new-borns and juveniles living in the Wayag lagoon and Fam Islands nursery areas we discovered recently.”
 

Is ayahuasca safe? New study tallies adverse events

Global Ayahuasca Survey finds 70% experience physical and 55% mental health adverse effects, but only 2.3% of participants reporting physical adverse events required medical attention

Peer-Reviewed Publication

PLOS

Preparation of ayahuasca (from B. caapi and P. viridis) 

IMAGE: PREPARATION OF AYAHUASCA (FROM B. CAAPI AND P. VIRIDIS) view more 

CREDIT: DANIEL PERKINS, CC-BY 4.0 (HTTPS://CREATIVECOMMONS.ORG/LICENSES/BY/4.0/)

There is a high rate of adverse physical effects and challenging psychological effects from using the plant-based psychoactive ayahuasca, though they are generally not severe, according to a new study published this week in the open-access journal PLOS Global Public Health by Daniel Perkins of University of Melbourne, Australia, and colleagues.

Ayahuasca is a South American psychoactive brewed drink used in traditional medicine and ceremony. Its contemporary use has been expanding throughout the world for mental health purposes and for spiritual and personal growth. Although clinical trials and observational studies have examined the potential benefits of ayahuasca, few have analyzed its adverse effects.

In the new study, the researchers used data from an online Global Ayahuasca survey carried out between 2017 and 2019, involving 10,836 people from more than 50 countries who were at least 18 years old and had used ayahuasca at least once. Information on participants’ age, physical and mental health and history and context of ayahuasca use was collected.

Overall, acute physical health adverse effects were reported by 69.9% of the sample, with the most common effects being vomiting and nausea (68.2% of participants), headache (17.8%) and abdominal pain (12.8%). Only 2.3% of participants reporting physical adverse events required medical attention for this issue. Among all participants, 55% also reported adverse mental health effects, including hearing or seeing things (28.5%), feeling disconnected or alone (21.0%), and having nightmares or disturbing thoughts (19.2%). However, of all respondents identifying these mental health effects, 87.6% believed they were completely or somewhat part of a positive growth process.

The researchers also identified several factors that predispose people to the adverse physical events, including older age, having a physical health condition or substance use disorder, lifetime ayahuasca use and taking ayahuasca in a non-supervised context.

The authors make the observation that ayahuasca has notable, although rarely severe, adverse effects according to the standards used for assessing prescription medicines. In that sense, they state that ayahuasca practices can hardly be assessed with the same parameters used for prescription medicines, since the myriad of its effects include challenging experiences that are intrinsic to the experience, some of which are considered as part of its healing process.

The authors add: “Many are turning to ayahuasca due to disenchantment with conventional Western mental health treatments, however the disruptive power of this traditional medicine should not be underestimated, commonly resulting in mental health or emotional challenges during assimilation. While these are usually transitory and seen as part of a beneficial growth process, risks are greater for vulnerable individuals or when used in unsupportive contexts.”

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In your coverage please use this URL to provide access to the freely available article in PLOS Global Public Healthhttps://journals.plos.org/globalpublichealth/article?id=10.1371/journal.pgph.0000438

Citation: Bouso JC, Andión Ó, Sarris JJ, Scheidegger M, Tófoli LF, Opaleye ES, et al. (2022) Adverse effects of ayahuasca: Results from the Global Ayahuasca Survey. PLOS Glob Public Health 2(11): e0000438. https://doi.org/10.1371/journal.pgph.0000438

Author Countries: Spain, Brazil, Australia, Switzerland,

Funding: The authors received no specific funding for this work.

Mums’ activity levels may depend on number and ages of children


Peer-Reviewed Publication

UNIVERSITY OF CAMBRIDGE

Less than half of mums meet the recommended levels of moderate-to-vigorous physical activity – and mothers of younger children manage to do the least, Cambridge and Southampton researchers have found.

Physical activity – particularly when it is moderate to vigorous – has many health benefits, decreasing the risk of a wide range of diseases from cancer to type 2 diabetes and cardiovascular disease, as well as helping maintain a healthy weight and better mental health.

Evidence suggests physical activity can help parents cope with the daily challenges of being a parent and strengthen relationships with children if they are active together. However, parents tend to be less active than non-parents.

To examine how family composition affected the amount of physical activity mothers engaged in, researchers at the University of Cambridge and University of Southampton analysed data from 848 women who participated in the UK Southampton Women’s Survey.  The women, aged 20-34 years, were recruited between 1998 and 2002 and followed up over subsequent years. They were given accelerometers to assess their levels of activity. The results are published today in PLOS ONE.

Women with school-aged children did on average around 26 mins* of moderate-to-vigorous physical activity per day, whereas mothers with only younger children (aged four years or under) managed around 18 mins* per day.

Having more than one child meant mothers managed only around 21 mins* of moderate-to-vigorous physical activity per day, but interestingly, mums with multiple children all under five years old did more light intensity activity than those with children of school-age.

Less than 50% of mothers met the recommended levels of moderate-to-vigorous physical activity (150 minutes per week), regardless of the ages of their children.

Dr Kathryn Hesketh from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge said: “When you have small children, your parental responsibilities can be all-consuming, and it’s often hard to find the time to be active outside of time spent caring for your children. Exercise is often therefore one of the first things to fall by the wayside, and so most of the physical activity mums manage to do seems to be of a lower intensity.

“However, when children go to school, mums manage to do more physical activity. There are a number of possible reasons why this might be the case, including more opportunities to take part in higher intensity activities with their children; you may return to active commuting; or feel more comfortable using time to be active alone.”

Rachel Simpson, a PhD student in the MRC Epidemiology Unit, added: “There are clear benefits, both short term and long term, from doing more physical activity, particularly if it increases your heart rate. But the demands of being a mother can make it hard to find the time. We need to consider ways not only to encourage mums, but to make it as easy as possible for busy mums, especially those with younger children, to increase the amount of higher intensity physical activity they do.”

Professor Keith Godfrey from the MRC Lifecourse Epidemiology Centre and the NIHR Southampton Biomedical Research Centre said: “It is perhaps not unexpected that mothers who have young children or several children engage in less intense physical activity, but this is the first study that has quantified the significance of this reduction. More needs to be done by local government planners and leisure facility providers to support mothers in engaging in physical activity.”

*Note: these are mean averages

Reference
Simpson, RF et al. The association between number and ages of children and the physical activity of mothers: cross-sectional analyses from the Southampton Women’s Survey. PLOS ONE; 16 Nov 2022; DOI: 10.1371/journal.pone.027696

Earth can regulate its own temperature over millennia, new study finds

Scientists have confirmed that a “stabilizing feedback” on 100,000-year timescales keeps global temperatures in check

Peer-Reviewed Publication

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

The Earth’s climate has undergone some big changes, from global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation. And yet life, for the last 3.7 billion years, has kept on beating.

Now, a study by MIT researchers in Science Advances confirms that the planet harbors a “stabilizing feedback” mechanism that acts over hundreds of thousands of years to pull the climate back from the brink, keeping global temperatures within a steady, habitable range.

Just how does it accomplish this? A likely mechanism is “silicate weathering” — a geological process by which the slow and steady weathering of silicate rocks involves chemical reactions that ultimately draw carbon dioxide out of the atmosphere and into ocean sediments, trapping the gas in rocks.

Scientists have long suspected that silicate weathering plays a major role in regulating the Earth’s carbon cycle. The mechanism of silicate weathering could provide a geologically constant force in keeping carbon dioxide — and global temperatures — in check. But there’s never been direct evidence for the continual operation of such a feedback, until now.

The new findings are based on a study of paleoclimate data that record changes in average global temperatures over the last 66 million years. The MIT team applied a mathematical analysis to see whether the data revealed any patterns characteristic of stabilizing phenomena that reined in global temperatures on a  geologic timescale.

They found that indeed there appears to be a consistent pattern in which the Earth’s temperature swings are dampened over timescales of hundreds of thousands of years. The duration of this effect is similar to the timescales over which silicate weathering is predicted to act.

The results are the first to use actual data to confirm the existence of a stabilizing feedback, the mechanism of which is likely silicate weathering. This stabilizing feedback would explain how the Earth has remained habitable through dramatic climate events in the geologic past.

“On the one hand, it’s good because we know that today’s global warming will eventually be canceled out  through this stabilizing feedback,” says Constantin Arnscheidt, a graduate student in MIT’s Department of Earth, Atmospheric, and Planetary Sciences (EAPS). “But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues.”

The study is co-authored by Arnscheidt and Daniel Rothman, professor of geophysics at MIT.

Stability in data

Scientists have previously seen hints of a climate-stabilizing effect in the Earth’s carbon cycle: Chemical analyses of ancient rocks have shown that the flux of carbon in and out of Earth’s surface environment has remained relatively balanced, even through dramatic swings in global temperature. Furthermore, models of silicate weathering predict that the process should have some stabilizing effect on the global climate. And finally, the fact of the Earth’s enduring habitability points to some inherent, geologic check on extreme temperature swings.

“You have a planet whose climate was subjected to so many dramatic external changes. Why did life survive all this time? One argument is that we need some sort of stabilizing mechanism to keep temperatures suitable for life,” Arnscheidt says. “But it's never been demonstrated from data that such a mechanism has consistently controlled Earth's climate.”

Arnscheidt and Rothman sought to confirm whether a stabilizing feedback has indeed been at work, by looking at  data of global temperature fluctuations through geologic history. They worked with a range of global temperature records compiled by other scientists, from the chemical composition of ancient marine fossils and shells, as well as preserved Antarctic ice cores.

“This whole study is only possible because there have been great advances in improving the resolution of these deep-sea temperature records,” Arnscheidt notes. “Now we have data going back 66 million years, with data points at most thousands of years apart.”

Speeding to a stop

To the data, the team applied the mathematical theory of stochastic differential equations, which is commonly used to reveal patterns in widely fluctuating datasets.

“We realized this theory makes predictions for what you would expect Earth’s temperature history to look like if there had been feedbacks acting on certain timescales,” Arnscheidt explains.

Using this approach, the team analyzed the history of average global temperatures over the last 66 million years, considering the entire period over different timescales, such as tens of thousands of years versus hundreds of thousands, to see whether any patterns of stabilizing feedback emerged within each timescale.

“To some extent, it’s like your car is speeding down the street, and when you put on the brakes, you slide for a long time before you stop,” Rothman says. “There’s a timescale over which frictional resistance, or a stabilizing feedback, kicks in, when the system returns to a steady state.”

Without stabilizing feedbacks, fluctuations of global temperature should grow with timescale. But the team’s analysis revealed a regime in which fluctuations did not grow, implying that a stabilizing mechanism reigned in the climate before fluctuations grew too extreme. The timescale for this stabilizing effect — hundreds of thousands of years — coincides with what scientists predict for silicate weathering.

Interestingly, Arnscheidt and Rothman found that on longer timescales, the data did not reveal any stabilizing feedbacks. That is, there doesn’t appear to be any recurring pull-back of global temperatures on timescales longer than a million years. Over these longer timescales, then, what has kept global temperatures in check?

“There’s an idea that chance may have played a major role in determining why, after more than 3 billion years, life still exists,” Rothman offers.

In other words, as the Earth’s temperatures fluctuate over longer stretches, these fluctuations may just happen to be small enough in the geologic sense, to be within a range that a stabilizing feedback, such as silicate weathering, could periodically keep the climate in check, and more to the point, within a habitable zone.

“There are two camps: Some say random chance is a good enough explanation, and others say there must be a stabilizing feedback,” Arnscheidt says. “We’re able to show, directly from data, that the answer is probably somewhere in between. In other words, there was some stabilization, but pure luck likely also played a role in keeping Earth continuously habitable.”

This research was supported in part by a MathWorks fellowship and the National Science Foundation.

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Written by Jennifer Chu, MIT News Office