Bronze Age farmers gave preferential treatment to cows over domesticated sheep, goats

The movements of ancient crop and animal domesticates across prehistoric Eurasia are well-documented in the archaeological record. What is less well understood: How Bronze Age farmers and herders incorporated newly introduced domesticates -- like cows from southwestern Asia -- into their long-standing animal husbandry and culinary traditions.

New research led by archaeologists at Washington University in St. Louis shows that meat and dairy played a more significant role in human diets in Bronze Age China than previously thought. The analysis also suggests that farmers and herders tended to sheep and goats differently than they did their cows, unlike in other parts of the world -- keeping cows closer to home and feeding them the byproducts of grains that they were growing for their own consumption, like the grass stalks from millet plants.

The study published in Scientific Reports integrates new and previously published data from nine sites along the Hexi Corridor, a key region between the Gobi Desert and Tibetan Plateau that facilitated the movement of ancient crops between Central and East Asia.

Petra Vaiglova, postdoctoral research associate, and Xinyi Liu, associate professor of archaeology in Arts & Sciences, based their analysis on bone records and other isotopic data from humans, animals and plants.

"Using the method of stable isotope analysis, we looked at the diets of the local herbivores that were managed in the Bronze Age Hexi Corridor of northwestern China," Vaiglova said. "The results showed that cattle and sheep or goats were managed distinctly in the different ecological niches across the study region. We propose that this was a result of varying management choices made by the local farmers, who aimed to strike a balance between tradition and innovation.

"In previous research, this method has been applied to understanding the nature of human diets, and the role of different domesticates in it," she said. "In this paper, we switched focus to trying to understand the minutiae of animal diets -- and what that tells us about animal management in the Bronze Age."

While sheep and goats seem to have eaten naturally available vegetation by grazing in the vicinity of the villages, the scientists found evidence that cattle were both grazed and fed. The cattle bones that the researchers analyzed exhibited a higher input of plants that are more adapted to arid conditions in places where these plants contributed little to the natural vegetation. This group of crops includes millet, which was originally cultivated in Eastern Asia.

These findings suggest that cattle diets were more influenced by human provisioning and that cattle may therefore have been reared closer to the human settlements than sheep and goats.

Liu and other researchers in his laboratory at Washington University study how social and culinary systems react to novel crops and exotic domestic animals in China. His research has revealed how foreign innovations adopted in ancient Central China were transformed within existing and highly organized social and cultural systems.

"Our results suggest a similar process in the adoption and localization of cattle in the Hexi Corridor, an animal domesticated in a markedly different environment," Liu said. "In locations with limited grazing lands suitable for pasturing of cattle, people adapted the local pig-rearing economy towards cattle stall-feeding."

These conclusions resonate with modern ethnographic examples from North China, the researchers said, where cattle are more tethered to human settlements, rather than being allowed to roam on local or more distant pastures alongside sheep and goats.

Understanding past farming and dietary conditions can help us with some of the challenges we face in today's world, Liu said. Those challenges are as much environmental as social.

"In the context of a warming climate, where soil moisture is predicted to be increasingly depleted on a global scale, one can draw parallels to the Mid-Holocene conditions of northwest China," Liu said.

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Climate change widespread, rapid, and intensifying: IPCC

Scientists are observing changes in the Earth's climate in every region and across the whole climate system, according to the latest Intergovernmental Panel on Climate Change (IPCC) Report, released today. Many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some of the changes already set in motion -- such as continued sea level rise -- are irreversible over hundreds to thousands of years.

However, strong and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases would limit climate change. While benefits for air quality would come quickly, it could take 20-30 years to see global temperatures stabilize, according to the IPCC Working Group I report, Climate Change 2021: the Physical Science Basis, approved on Friday by 195 member governments of the IPCC, through a virtual approval session that was held over two weeks starting on July 26.

The Working Group I report is the first installment of the IPCC's Sixth Assessment Report (AR6), which will be completed in 2022.

"This report reflects extraordinary efforts under exceptional circumstances," said Hoesung Lee, Chair of the IPCC. "The innovations in this report, and advances in climate science that it reflects, provide an invaluable input into climate negotiations and decision-making."

Faster warming

The report provides new estimates of the chances of crossing the global warming level of 1.5°C in the next decades, and finds that unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to close to 1.5°C or even 2°C will be beyond reach.

The report shows that emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming since 1850-1900, and finds that averaged over the next 20 years, global temperature is expected to reach or exceed 1.5°C of warming. This assessment is based on improved observational datasets to assess historical warming, as well progress in scientific understanding of the response of the climate system to human-caused greenhouse gas emissions.

"This report is a reality check," said IPCC Working Group I Co-Chair Valérie Masson-Delmotte. "We now have a much clearer picture of the past, present and future climate, which is essential for understanding where we are headed, what can be done, and how we can prepare."

Every region facing increasing changes

Many characteristics of climate change directly depend on the level of global warming, but what people experience is often very different to the global average. For example, warming over land is larger than the global average, and it is more than twice as high in the Arctic.

"Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming," said IPCC Working Group I Co-Chair Panmao Zhai.

The report projects that in the coming decades climate changes will increase in all regions. For 1.5°C of global warming, there will be increasing heat waves, longer warm seasons and shorter cold seasons. At 2°C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health, the report shows.

But it is not just about temperature. Climate change is bringing multiple different changes in different regions -- which will all increase with further warming. These include changes to wetness and dryness, to winds, snow and ice, coastal areas and oceans. For example:
 

• Climate change is intensifying the water cycle. This brings more intense rainfall and associated flooding, as well as more intense drought in many regions.
• Climate change is affecting rainfall patterns. In high latitudes, precipitation is likely to increase, while it is projected to decrease over large parts of the subtropics. Changes to monsoon precipitation are expected, which will vary by region.
• Coastal areas will see continued sea level rise throughout the 21st century, contributing to more frequent and severe coastal flooding in low-lying areas and coastal erosion. Extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century.
• Further warming will amplify permafrost thawing, and the loss of seasonal snow cover, melting of glaciers and ice sheets, and loss of summer Arctic sea ice.
• Changes to the ocean, including warming, more frequent marine heatwaves, ocean acidification, and reduced oxygen levels have been clearly linked to human influence. These changes affect both ocean ecosystems and the people that rely on them, and they will continue throughout at least the rest of this century.
• For cities, some aspects of climate change may be amplified, including heat (since urban areas are usually warmer than their surroundings), flooding from heavy precipitation events and sea level rise in coastal cities.

For the first time, the Sixth Assessment Report provides a more detailed regional assessment of climate change, including a focus on useful information that can inform risk assessment, adaptation, and other decision-making, and a new framework that helps translate physical changes in the climate -- heat, cold, rain, drought, snow, wind, coastal flooding and more -- into what they mean for society and ecosystems.

This regional information can be explored in detail in the newly developed Interactive Atlas https://interactive-atlas.ipcc.ch/ as well as regional fact sheets, the technical summary, and underlying report.

Human influence on the past and future climate

"It has been clear for decades that the Earth's climate is changing, and the role of human influence on the climate system is undisputed," said Masson-Delmotte. Yet the new report also reflects major advances in the science of attribution -- understanding the role of climate change in intensifying specific weather and climate events such as extreme heat waves and heavy rainfall events.

The report also shows that human actions still have the potential to determine the future course of climate. The evidence is clear that carbon dioxide (CO2) is the main driver of climate change, even as other greenhouse gases and air pollutants also affect the climate.

"Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions, and reaching net zero CO2 emissions. Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate," said Zhai.

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NASA's TESS tunes into an all-sky 'symphony' of red giant stars

Using observations from NASA's Transiting Exoplanet Survey Satellite (TESS), astronomers have identified an unprecedented collection of pulsating red giant stars all across the sky. These stars, whose rhythms arise from internal sound waves, provide the opening chords of a symphonic exploration of our galactic neighborhood.

TESS primarily hunts for worlds beyond our solar system, also known as exoplanets. But its sensitive measurements of stellar brightness make TESS ideal for studying stellar oscillations, an area of research called asteroseismology.

Hon presented the research during the second TESS Science Conference, an event supported by the Massachusetts Institute of Technology in Cambridge -- held virtually from Aug. 2 to 6 -- where scientists discuss all aspects of the mission. The Astrophysical Journal has accepted a paper describing the findings, led by Hon.

Sound waves traveling through any object -- a guitar string, an organ pipe, or the interiors of Earth and the Sun -- can reflect and interact, reinforcing some waves and canceling out others. This can result in orderly motion called standing waves, which create the tones in musical instruments.

Just below the surfaces of stars like the Sun, hot gas rises, cools, and then sinks, where it heats up again, much like a pan of boiling water on a hot stove. This motion produces waves of changing pressure -- sound waves -- that interact, ultimately driving stable oscillations with periods of a few minutes that produce subtle brightness changes. For the Sun, these variations amount to a few parts per million. Giant stars with masses similar to the Sun's pulsate much more slowly, and the corresponding brightness changes can be hundreds of times greater.

Oscillations in the Sun were first observed in the 1960s. Solar-like oscillations were detected in thousands of stars by the French-led Convection, Rotation and planetary Transits (CoRoT) space telescope, which operated from 2006 to 2013. NASA's Kepler and K2 missions, which surveyed the sky from 2009 to 2018, found tens of thousands of oscillating giants. Now TESS extends this number by another 10 times.

"With a sample this large, giants that might occur only 1% of the time become pretty common," said co-author Jamie Tayar, a Hubble Fellow at the University of Hawaii. "Now we can start thinking about finding even rarer examples."

The physical differences between a cello and a violin produce their distinctive voices. Similarly, the stellar oscillations astronomers observe depend on each star's interior structure, mass, and size. This means asteroseismology can help determine fundamental properties for large numbers of stars with accuracies not achievable in any other way.

"Our initial result, using stellar measurements across TESS's first two years, shows that we can determine the masses and sizes of these oscillating giants with precision that will only improve as TESS goes on," said Marc Hon, a NASA Hubble Fellow at the University of Hawaii in Honolulu. "What's really unparalleled here is that TESS's broad coverage allows us to make these measurements uniformly across almost the entire sky."

When stars similar in mass to the Sun evolve into red giants, the penultimate phase of their stellar lives, their outer layers expand by 10 or more times. These vast gaseous envelopes pulsate with longer periods and larger amplitudes, which means their oscillations can be observed in fainter and more numerous stars.

TESS monitors large swaths of the sky for about a month at a time using its four cameras. During its two-year primary mission, TESS covered about 75% of the sky, each camera capturing a full image measuring 24-by-24 degrees every 30 minutes. In mid-2020, the cameras began collecting these images at an even faster pace, every 10 minutes.

The images were used to develop light curves -- graphs of changing brightness -- for nearly 24 million stars over 27 days, the length of time TESS stares at each swath of the sky. To sift through this immense accumulation of measurements, Hon and his colleagues taught a computer to recognize pulsating giants. The team used machine learning, a form of artificial intelligence that trains computers to make decisions based on general patterns without explicitly programming them.

To train the system, the team used Kepler light curves for more than 150,000 stars, of which some 20,000 were oscillating red giants. When the neural network finished processing all of the TESS data, it had identified a chorus of 158,505 pulsating giants.

Next, the team found distances for each giant using data from ESA's (the European Space Agency's) Gaia mission, and plotted the masses of these stars across the sky. Stars more massive than the Sun evolve faster, becoming giants at younger ages. A fundamental prediction in galactic astronomy is that younger, higher-mass stars should lie closer to the plane of the galaxy, which is marked by the high density of stars that create the glowing band of the Milky Way in the night sky.

"Our map demonstrates for the first time empirically that this is indeed the case across nearly the whole sky," said co-author Daniel Huber, an assistant professor for astronomy at the University of Hawaii. "With the help of Gaia, TESS has now given us tickets to a red giant concert in the sky."

Read more at Science Daily

To do or not to do: Cracking the code of motivation

Our motivation to put effort for achieving a goal is controlled by a reward system wired in the brain. However, many neuropathological conditions impair the reward system, diminishing the will to work. Recently, scientists in Japan experimentally manipulated the reward system network of monkeys and studied their behavior. They deciphered a few critical missing pieces of the reward system puzzle that might help in increasing motivation.

Why do we do things? What persuades us to put an effort to achieve goals, however mundane? What, for instance, drives us to search for food? Neurologically, the answer is hidden in the reward system of the brain -- an evolutionary mechanism that controls our willingness to work or to take a risk as the cost of achieving our goals and enjoying the perceived rewards. In people suffering from depression, schizophrenia, or Parkinson's disease, often the reward system of the brain is impaired, leading them to a state of diminished motivation for work or chronic fatigue.

To find a way to overcome the debilitating behavioral blocks, neuroscientists are investigating the "anatomy" of the reward system and determining how it evaluates the cost-benefit trade-off while deciding on whether to pursue a task. Recently, Dr. Yukiko Hori of National Institutes for Quantum and Radiological Science and Technology, Japan, along with her colleagues have conducted a study that has answered some of the most critical questions on benefit- and cost-based motivation of reward systems. The findings of their study have been published in PLoS Biology.

Discussing what prompted them to undertake the study, Dr. Hori explains: "Mental responses such as 'feeling more costly and being too lazy to act,' are often a problem in patients with mental disorders such as depression, and the solution lies in the better understanding of what causes such responses. We wanted to look deeper into the mechanism of motivational disturbances in the brain."

To do so, Dr. Hori and her team focused on dopamine (DA), the "neurotransmitter" or the signaling molecule that plays the central role in inducing motivation and regulation of behavior based on cost-benefit analysis. The effect of DA in the brain transmits via DA receptors, or molecular anchors that bind the DA molecules and propagate the signals through the neuronal network of the brain. However, as these receptors have distinct roles in DA signal transduction, it was imperative to assess their relative impacts on DA signaling. Therefore, using macaque monkeys as models, the researchers aimed to decipher the roles of two classes of DA receptors -- the D1-like receptor (D1R) and the D2-like receptor (D2R) -- in developing benefit- and cost-based motivation.

In their study, the researchers first trained the animals to perform "reward size" tasks and "work/delay tasks." These tasks allowed them to measure how perceived reward size and required effort influenced the task-performing behavior. Dr. Takafumi Minamimoto, the corresponding author of the study explains, "We systematically manipulated the D1R and D2R of these monkeys by injecting them with specific receptor-binding molecules that dampened their biological responses to DA signaling. By positron emission tomography-based imaging of the brains of the animals, the extent of bindings or blockades of the receptors was measured." Then, under experimental conditions, they offered the monkeys the chance to perform tasks to achieve rewards and noted whether the monkeys accepted or refused to perform the tasks and how quickly they responded to the cues related to the tasks.

Analysis of these data unearthed some intriguing insights into the neurobiological mechanism of the decision-making process. The researchers observed that decision-making based on perceived benefit and cost required the involvement of both D1R and D2R, in both incentivizing the motivation (the process in which the size of the rewards inspired the monkeys to perform the tasks) and in increasing delay discounting (the tendency to prefer immediate, smaller rewards over larger, but delayed rewards). It also became clear that DA transmission via D1R and D2R regulates the cost-based motivational process by distinct neurobiological processes for benefits or "reward availability" and costs or "energy expenditure associated with the task." However, workload discounting -- the process of discounting the value of the rewards based on the proportion of the effort needed -- was exclusively related to D2R manipulation.

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Eating more plant foods may lower heart disease risk in young adults, older women

Eating more nutritious, plant-based foods is heart-healthy at any age, according to two research studies published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

In two separate studies analyzing different measures of healthy plant food consumption, researchers found that both young adults and postmenopausal women had fewer heart attacks and were less likely to develop cardiovascular disease when they ate more healthy plant foods.

The American Heart Association Diet and Lifestyle Recommendations suggest an overall healthy dietary pattern that emphasizes a variety of fruits and vegetables, whole grains, low-fat dairy products, skinless poultry and fish, nuts and legumes and non-tropical vegetable oils. It also advises limited consumption of saturated fat, trans fat, sodium, red meat, sweets and sugary drinks.

One study, titled "A Plant-Centered Diet and Risk of Incident Cardiovascular Disease during Young to Middle Adulthood," evaluated whether long-term consumption of a plant-centered diet and a shift toward a plant-centered diet starting in young adulthood are associated with a lower risk of cardiovascular disease in midlife.

"Earlier research was focused on single nutrients or single foods, yet there is little data about a plant-centered diet and the long-term risk of cardiovascular disease," said Yuni Choi, Ph.D., lead author of the young adult study and a postdoctoral researcher in the division of epidemiology and community health at the University of Minnesota School of Public Health in Minneapolis.

Choi and colleagues examined diet and the occurrence of heart disease in 4,946 adults enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were 18- to 30-years-old at the time of enrollment (1985-1986) in this study and were free of cardiovascular disease at that time. Participants included 2,509 Black adults and 2,437 white adults (54.9% women overall) who were also analyzed by education level (equivalent to more than high school vs. high school or less). Participants had eight follow-up exams from 1987-88 to 2015-16 that included lab tests, physical measurements, medical histories and assessment of lifestyle factors. Unlike randomized controlled trials, participants were not instructed to eat certain things and were not told their scores on the diet measures, so the researchers could collect unbiased, long-term habitual diet data.

After detailed diet history interviews, the quality of the participants diets was scored based on the A Priori Diet Quality Score (APDQS) composed of 46 food groups at years 0, 7 and 20 of the study. The food groups were classified into beneficial foods (such as fruits, vegetables, beans, nuts and whole grains); adverse foods (such as fried potatoes, high-fat red meat, salty snacks, pastries and soft drinks); and neutral foods (such as potatoes, refined grains, lean meats and shellfish) based on their known association with cardiovascular disease.

Participants who received higher scores ate a variety of beneficial foods, while people who had lower scores ate more adverse foods. Overall, higher values correspond to a nutritionally rich, plant-centered diet.

"As opposed to existing diet quality scores that are usually based on small numbers of food groups, APDQS is explicit in capturing the overall quality of diet using 46 individual food groups, describing the whole diet that the general population commonly consumes. Our scoring is very comprehensive, and it has many similarities with diets like the Dietary Guidelines for Americans Healthy Eating Index (from the U.S. Department of Agriculture's Food and Nutrition Service), the DASH (Dietary Approaches to Stop Hypertension) diet and the Mediterranean diet," said David E. Jacobs Jr., Ph.D., senior author of the study and Mayo Professor of Public Health in the division of epidemiology and community health at the University of Minnesota School of Public Health in Minneapolis.

Researchers found:
 

• During 32 years of follow-up, 289 of the participants developed cardiovascular disease (including heart attack, stroke, heart failure, heart-related chest pain or clogged arteries anywhere in the body).
• People who scored in the top 20% on the long-term diet quality score (meaning they ate the most nutritionally rich plant foods and fewer adversely rated animal products) were 52% less likely to develop cardiovascular disease, after considering several factors (including age, sex, race, average caloric consumption, education, parental history of heart disease, smoking and average physical activity).
• In addition, between year 7 and 20 of the study when participants ages ranged from 25 to 50, those who improved their diet quality the most (eating more beneficial plant foods and fewer adversely rated animal products) were 61% less likely to develop subsequent cardiovascular disease, in comparison to the participants whose diet quality declined the most during that time.
• There were few vegetarians among the participants, so the study was not able to assess the possible benefits of a strict vegetarian diet, which excludes all animal products, including meat, dairy and eggs.

"A nutritionally rich, plant-centered diet is beneficial for cardiovascular health. A plant-centered diet is not necessarily vegetarian," Choi said. "People can choose among plant foods that are as close to natural as possible, not highly processed. We think that individuals can include animal products in moderation from time to time, such as non-fried poultry, non-fried fish, eggs and low-fat dairy."

Because this study is observational, it cannot prove a cause-and-effect relationship between diet and heart disease.

Other co-authors are Nicole Larson, Ph.D.; Lyn M. Steffen, Ph.D.; Pamela J. Schreiner, Ph.D.; Daniel D. Gallaher, Ph.D.; Daniel A. Duprez, M.D., Ph.D.; James M. Shikany, Dr.P.H.; and Jamal S. Rana, M.D., Ph.D.

The study was funded by the National Heart, Lung and Blood Institute of the National Institutes of Health; Healthy Food Healthy Lives Institute at the University of Minnesota; and the MnDrive Global Food Ventures Professional Development Program at the University of Minnesota.

In another study, "Relationship Between a Plant-Based Dietary Portfolio and Risk of Cardiovascular Disease: Findings from the Women's Health Initiative (WHI) Prospective Cohort Study," researchers, in collaboration with WHI investigators led by Simin Liu, M.D., Ph.D., at Brown University, evaluated whether or not diets that included a dietary portfolio of plant-based foods with U.S. Food and Drug Administration-approved health claims for lowering "bad" cholesterol levels (known as the "Portfolio Diet") were associated with fewer cardiovascular disease events in a large group of postmenopausal women.

The "Portfolio Diet" includes nuts; plant protein from soy, beans or tofu; viscous soluble fiber from oats, barley, okra, eggplant, oranges, apples and berries; plant sterols from enriched foods and monounsaturated fats found in olive and canola oil and avocadoes; along with limited consumption of saturated fats and dietary cholesterol. Previously, two randomized trials demonstrated that reaching high target levels of foods included in the Portfolio Diet resulted in significant lowering of "bad" cholesterol or low-density lipoprotein cholesterol (LDL-C), more so than a traditional low-saturated-fat National Cholesterol and Education Program diet in one study and on par with taking a cholesterol-lowering statin medication in another.

The study analyzed whether postmenopausal women who followed the Portfolio Diet experienced fewer heart disease events. The study included 123,330 women in the U.S. who participated in the Women's Health Initiative, a long-term national study looking at risk factors, prevention and early detection of serious health conditions in postmenopausal women. When the women in this analysis enrolled in the study between 1993 and 1998, they were between 50-79 years old (average age of 62) and did not have cardiovascular disease. The study group was followed until 2017 (average follow-up time of 15.3 years). Researchers used self-reported food-frequency questionnaires data to score each woman on adherence to the Portfolio Diet.

The researchers found:
 

• Compared to women who followed the Portfolio Diet less frequently, those with the closest alignment were 11% less likely to develop any type of cardiovascular disease, 14% less likely to develop coronary heart disease and 17% less likely to develop heart failure.
• There was no association between following the Portfolio Diet more closely and the occurrence of stroke or atrial fibrillation.

"These results present an important opportunity, as there is still room for people to incorporate more cholesterol-lowering plant foods into their diets. With even greater adherence to the Portfolio dietary pattern, one would expect an association with even less cardiovascular events, perhaps as much as cholesterol-lowering medications. Still, an 11% reduction is clinically meaningful and would meet anyone's minimum threshold for a benefit. The results indicate the Portfolio Diet yields heart-health benefits," said John Sievenpiper, M.D., Ph.D., senior author of the study at St. Michael's Hospital, a site of Unity Health Toronto in Ontario, Canada, and associate professor of nutritional sciences and medicine at the University of Toronto.

The researchers believe the results highlight possible opportunities to lower heart disease by encouraging people to consume more foods in the Portfolio Diet.

"We also found a dose response in our study, meaning that you can start small, adding one component of the Portfolio Diet at a time, and gain more heart-health benefits as you add more components," said Andrea J. Glenn, M.Sc., R.D., lead author of the study and a doctoral student at St. Michael's Hospital in Toronto and in nutritional sciences at the University of Toronto.

Although the study was observational and cannot directly establish a cause-and-effect relation between diet and cardiovascular events, researchers feel it provides a most reliable estimate for the diet-heart relation to-date due to its study design (included well-validated food frequency questionnaires administered at baseline and year three in a large population of highly dedicated participants). Nevertheless, the investigators report that these findings need to be further investigated in additional populations of men or younger women.

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Giraffes are as socially complex as elephants, study finds

Scientists at the University of Bristol have discovered evidence that giraffes are a highly socially complex species.

Traditionally, giraffes were thought to have little or no social structure, and only fleeting, weak relationships. However in the last ten years, research has shown that giraffe social organisation is much more advanced than once thought.

In a paper published in today in the journal Mammal Review, Zoe Muller, of Bristol's School of Biological Sciences, has demonstrated that giraffes spend up to 30% of their lives in a post-reproductive state. This is comparable to other species with highly complex social structures and cooperative care, such as elephants and killer-whales which spend 23% and 35% of their lives in a post-reproductive state respectively. In these species, it has been demonstrated that the presence of post-menopausal females offers survival benefits for related offspring. In mammals -- and including humans -- this is known as the 'Grandmother hypothesis' which suggests that females live long past menopause so that they can help raise successive generations of offspring, thereby ensuring the preservation of their genes. Researchers propose that the presence of post-reproductive adult female giraffes could also function in the same way, and supports the author's assertion that giraffes are likely to engage in cooperative parenting, along matrilines, and contribute to the shared parental care of related kin.

Muller said: "It is baffling to me that such a large, iconic and charismatic African species has been understudied for so long. This paper collates all the evidence to suggest that giraffes are actually a highly complex social species, with intricate and high-functioning social systems, potentially comparable to elephants, cetaceans and chimpanzees.

"I hope that this study draws a line in the sand, from which point forwards, giraffes will be regarded as intelligent, group-living mammals which have evolved highly successful and complex societies, which have facilitated their survival in tough, predator-filled ecosystems."

For scientists to recognise giraffes as a socially complex species, Muller has suggested eight key areas for future research, including the need to understand the role that older, post-reproductive adults play in society and what fitness benefits they bring for group survival.

Muller added: "Recognising that giraffes have a complex cooperative social system and live in matrilineal societies will further our understanding of their behavioural ecology and conservation needs.

Read more at Science Daily

Highest-resolution measurements of asteroid surface temperatures ever obtained from Earth

A close examination of the millimeter-wavelength emissions from the asteroid Psyche, which NASA intends to visit in 2026, has produced the first temperature map of the object, providing new insight into its surface properties. The findings, described in a paper published in Planetary Science Journal (PSJ) on August 5, are a step toward resolving the mystery of the origin of this unusual object, which has been thought by some to be a chunk of the core of an ill-fated protoplanet.

Psyche orbits the sun in the asteroid belt, a donut-shaped region of space between Earth and Jupiter that contains more than a million rocky bodies that range in size from 10 meters to 946 kilometers in diameter.

With a diameter of more than 200 km, Psyche is the largest of the M-Type asteroids, an enigmatic class of asteroids that are thought to be metal rich and therefore potentially may be fragments of the cores of proto-planets that broke up as the solar system formed.

"The early solar system was a violent place, as planetary bodies coalesced and then collided with one another while settling into orbits around the sun," says Caltech's Katherine de Kleer, assistant professor of planetary science and astronomy and lead author of the PSJarticle. "We think that fragments of the cores, mantles, and crusts of these objects remain today in the form of asteroids. If that's true, it gives us our only real opportunity to directly study the cores of planet-like objects."

Studying such relatively tiny objects that are so far away from Earth (Psyche drifts at a distance that ranges between 179.5 and 329 million km from Earth) poses a significant challenge to planetary scientists, which is why NASA plans to send a probe to Psyche to examine it up close. Typically, thermal observations from Earth -- which measure the light emitted by an object itself rather than light from the sun reflected off of that object -- are in infrared wavelengths and can produce only 1-pixel images of asteroids. That one pixel does, however, reveal a lot of information; for example, it can be used to study the asteroid's thermal inertia, or how fast it heats up in sunlight and cools down in darkness.

"Low thermal inertia is typically associated with layers of dust, while high thermal inertia may indicate rocks on the surface," says Caltech's Saverio Cambioni, postdoctoral scholar in planetary science and co-author of the PSJ article. "However, discerning one type of landscape from the other is difficult." Data from viewing each surface location at many times of day provide much more detail, leading to an interpretation that is subject to less ambiguity, and which provide a more reliable prediction of landscape type prior to a spacecraft's arrival.

De Kleer and Cambioni, together with co-author Michael Shepard of Bloomsburg University in Pennsylvania, took advantage of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, which became fully operational in 2013, to obtain such data. The array of 66 radio telescopes enabled the team to map the thermal emissions from Psyche's entire surface at a resolution of 30 km (where each pixel is 30 km by 30 km) and generate an image of the asteroid composed of about 50 pixels.

This was possible because ALMA observed Psyche at millimeter wavelengths, which are longer (ranging from 1 to 10 millimeters) than the infrared wavelengths (typically between 5 and 30 microns). The use of longer wavelengths allowed the researchers to combine the data collected from the 66 telescopes to create a much larger effective telescope; the larger a telescope, the higher the resolution of the images it produces.

The study confirmed that Psyche's thermal inertia is high compared to that of a typical asteroid, indicating that Psyche has an unusually dense or conductive surface. When de Kleer, Cambioni, and Shepard analyzed the data, they also found that Psyche's thermal emission -- the amount of heat it radiates -- is just 60 percent of what would be expected from a typical surface with that thermal inertia. Because surface emission is affected by the presence of metal on the surface, their finding indicates that Psyche's surface is no less than 30 percent metal. An analysis of the polarization of the emission helped the researchers to roughly determine what form that metal takes. A smooth solid surface emits well-organized polarized light; the light emitted by Psyche, however, was scattered, suggesting that rocks on the surface are peppered with metallic grains.

"We've known for many years that objects in this class are not, in fact, solid metal, but what they are and how they formed is still an enigma," de Kleer says. The findings reinforce alternative proposals for Psyche's surface composition, including that Psyche could be a primitive asteroid that formed closer to the sun than it is today instead of a core of a fragmented protoplanet.

The techniques described in this study provide a new perspective on asteroid surface compositions. The team is now expanding its scope to apply these techniques to other large objects in the asteroid belt.

Read more at Science Daily

Lunar samples solve mystery of the moon's supposed magnetic shield

In 2024, a new age of space exploration will begin when NASA sends astronauts to the moon as part of their Artemis mission, a follow-up to the Apollo missions of the 1960s and 1970s.

Some of the biggest questions that scientists hope to explore include determining what resources are found in the moon's soil and how those resources might be used to sustain life.

In a paper published in the journal Science Advances, researchers at the University of Rochester, leading a team of colleagues at seven other institutions, report their findings on a major factor that influences the types of resources that may be found on the moon: whether or not the moon has had a long-lived magnetic shield at any point in its 4.53 billion-year history.

The presence or absence of a shield matters because magnetic shields protect astronomical bodies from harmful solar radiation. And the team's findings contradict some longstanding assumptions.

"This is a new paradigm for the lunar magnetic field," says first author John Tarduno, the William R. Kenan, Jr., Professor of Geophysics in the Department of Earth and Environmental Sciences and dean of research for Arts, Sciences & Engineering at Rochester.

Did the Moon Ever Have a Magnetic Field?

For years, Tarduno has been a leader in the field of paleomagnetism, studying the development of Earth's magnetic shield as a means to understanding planetary evolution and environmental change.

Earth's magnetic shield originates deep within the planet's core. There, swirling liquid iron generates electric currents, driving a phenomenon called the geodynamo, which produces the shield. The magnetic shield is invisible, but researchers have long recognized that it is vital for life on Earth's surface because it protects our planet from solar wind -- streams of radiation from the sun.

But has Earth's moon ever had a magnetic shield?

While the moon has no magnetic shield now, there has been debate over whether or not the moon may have had a prolonged magnetic shield at some point in its history.

"Since the Apollo missions, there has been this idea that the moon had a magnetic field that was as strong or even stronger than Earth's magnetic field at around 3.7 billion years ago," Tarduno says.

The belief that the moon had a magnetic shield was based on an initial dataset from the 1970s that included analyses of samples collected during the Apollo missions. The analyses showed that the samples had magnetization, which researchers believed was caused by the presence of a geodynamo.

But a couple of factors have since given researchers pause.

"The core of the moon is really small and it would be hard to actually drive that kind of magnetic field," Tarduno explains. "Plus, the previous measurements that record a high magnetic field were not conducted using heating experiments. They used other techniques that may not accurately record the magnetic field."

When Lunar Samples Meet Lasers

Tarduno and his colleagues tested glass samples gathered on previous Apollo missions, but used CO2 lasers to heat the lunar samples for a short amount of time, a method that allowed them to avoid altering the samples. They then used highly sensitive superconducting magnetometers to more accurately measure the samples' magnetic signals.

"One of the issues with lunar samples has been that the magnetic carriers in them are quite susceptible to alteration," Tarduno says. "By heating with a laser, there is no evidence of alteration in our measurements, so we can avoid the problems people may have had in the past."

The researchers determined that the magnetization in the samples could be the result of impacts from objects such as meteorites or comets -- not the result of magnetization from the presence of a magnetic shield. Other samples they analyzed had the potential to show strong magnetization in the presence of a magnetic field, but didn't show any magnetization, further indicating that the moon has never had a prolonged magnetic shield.

"If there had been a magnetic field on the moon, the samples we studied should all have acquired magnetization, but they haven't," Tarduno says. "That's pretty conclusive that the moon didn't have a long-lasting dynamo field."

Lack of Magnetic Shield Means an Abundance of Elements

Without the protection of a magnetic shield, the moon was susceptible to solar wind, which may have caused a variety of volatiles -- chemical elements and compounds that can be easily evaporated -- to become implanted in the lunar soil. These volatiles may include carbon, hydrogen, water, and helium 3, an isotope of helium that is not present in abundance on Earth.

"Our data indicates we should be looking at the high end of estimates of helium 3 because a lack of magnetic shield means more solar wind reaches the lunar surface, resulting in much deeper reservoirs of helium 3 than people thought previously," Tarduno says.

The research may help inform a new wave of lunar experiments based on data that will be gathered by the Artemis mission. Data from samples gathered during the mission will allow scientists and engineers to study the presence of volatiles and better determine if these materials can be extracted for human use. Helium 3, for instance, is currently used in medical imaging and cryogenics and is a possible future fuel source.

A lack of magnetic shielding also means that ancient lunar soils may hold records of past solar wind emissions. Analyzing cores of soil samples could therefore provide scientists with a better understanding of the evolution of the sun.

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Fasting may help ward off infections, study in mice suggests

Fasting before and during exposure to Salmonella enterica bacteria protects mice from developing a full-blown infection, in part due to changes in the animals' gut microbiomes,according to new research published in PLOS Pathogens by Bruce Vallance and colleagues at University of British Columbia, Canada.

When people or animals develop an infection, they often lose their appetite. However it remains controversial whether fasting protects a host from infection, or increases their susceptibility. In the new study, mice were fasted for 48 hours before and during oral infection with the bacteria Salmonella enterica serovar Typhimurium, a common cause of foodborne illness in people.

Fasting decreased the signs of bacterial infection compared to fed mice, including nearly eliminating all intestinal tissue damage and inflammation. When fasted animals were re-fed for a day after their fast, there was a dramatic increase in Salmonella numbers and invasion into the intestinal walls, although the associated inflammation was still attenuated compared to normal. The results did not hold true when mice were exposed to Salmonella intravenously instead of orally, and analyses of the microbiomes of mice showed significant changes associated with fasting and protection against infection. Moreover, fasting did not fully protect germ-free mice -- bred to lack a normal microbiome -- from Salmonella, suggesting that some of the protection was due to fasting's effect on the microbiome. Experiments using the bacteria Campylobacter jejuni confirmed that the effect of fasting was not limited to Salmonella, with similar results seen.

"These data suggest that therapeutic fasting or calorie restriction has the potential to beneficially modulate infectious and potentially non-infectious gastrointestinal diseases," the researchers conclude.

The researchers add, "Our research highlights the important role that food plays in regulating interactions between the host, enteric pathogens and the gut microbiome. When food is limited, the microbiome appears to sequester the nutrients that remain, preventing pathogens from acquiring the energy they need to infect the host. While more research is needed, fasting or otherwise adjusting food intake could be exploited therapeutically to modulate infectious diseases in the future."

From Science Daily

Leaping squirrels! Parkour is one of their many feats of agility

Videos of squirrels leaping from bendy branches across impossibly large gaps, parkouring off walls, scrambling to recover from tricky landings.

Just more YouTube content documenting the crazy antics of squirrels hell-bent on reaching peanuts?

No, these videos are part of a research study to understand the split-second decisions squirrels make routinely as they race through the tree canopy, jumping from branch to branch, using skills honed to elude deadly predators.

The payoff to understanding how squirrels learn the limits of their agility could be robots with better control to nimbly move through varied landscapes, such as the rubble of a collapsed building in search of survivors or to quickly access an environmental threat.

Biologists like Robert Full at the University of California, Berkeley, have shown over the last few decades how animals like geckos, cockroaches and squirrels physically move and how their bodies and limbs help them in sticky situations -- all of which have been applied to making more agile robots. But now they are tackling a harder problem: How do animals decide whether or not to take a leap? How do they assess their biomechanical abilities to know whether they can stick the landing?

"I see this as the next frontier: How are the decisions of movement shaped by our body? This is made far more challenging, because you also must assess your environment," said Full, a professor of integrative biology. "That's an important fundamental biology question. Fortunately, now we can understand how to embody control and explain innovation by creating physical models, like the most agile smart robots ever built."

In a paper appearing this week in the journal Science, Full and former UC Berkeley doctoral student Nathaniel Hunt, now an assistant professor of biomechanics at the University of Nebraska, Omaha, report on their most recent experiments on free-ranging squirrels, quantifying how they learn to leap from different types of launching pads -- some bendy, some not -- in just a few attempts, how they change their body orientation in midair based on the quality of their launch, and how they alter their landing maneuvers in real-time, depending on the stability of the final perch.

"As a model organism to understand the biological limits of balance and agility, I would argue that squirrels are second to none," Hunt said. "If we try to understand how squirrels do this, then we may discover general principles of high performance locomotion in the canopy and other complex terrains that apply to the movements of other animals and robots."

The experiments were conducted in a eucalyptus grove on the UC Berkeley campus, where Hunt enticed fox squirrels that roam the campus into sketchy situations where they had to decide whether to leap for a peanut or let it go.

Hunt and Full found that, as expected, the flimsier or more compliant the branch from which squirrels have to leap, the more cautious they are. But it took squirrels just a few attempts to adjust to different compliances.

"When they leap across a gap, they decide where to take off based on a tradeoff between branch flexibility and the size of the gap they must leap," Hunt said. "And when they encounter a branch with novel mechanical properties, they learn to adjust their launching mechanics in just a few jumps. This behavioral flexibility that adapts to the mechanics and geometry of leaping and landing structures is important to accurately leaping across a gap to land on a small target."

But they don't balance the bendiness of the launching branch and the gap distance equally. In fact, the compliance of the branch was six times more critical than the gap distance in deciding whether to jump.

This may be because squirrels know that their sharp claws will save them if they miscalculate. Their claws are so failproof, Hunt said, that none of the squirrels ever fell, despite wobbly leaps and over- or undershot landings.

"They're not always going to have their best performance -- they just have to be good enough," he said. "They have redundancy. So, if they miss, they don't hit their center of mass right on the landing perch, they're amazing at being able to grab onto it. They'll swing underneath, they'll swing over the top. They just don't fall."

That's where exploration and innovation come into play as squirrels search for the best leaping strategy.

"If they leap into the air with too much speed or too little speed, they can use a variety of landing maneuvers to compensate," Hunt said. "If they jump too far, they roll forward around the branch. If they jump short, they will land with their front legs and swing underneath before pulling themselves up on top of the perch. This combination of adaptive planning behaviors, learning control and reactive stabilizing maneuvers helps them move quickly through the branches without falling."

One unsuspected innovation was that during tricky jumps, squirrels would often reorient their bodies to push off a vertical surface, like in human parkour, to adjust their speed and insure a better landing. Parkour is a sport in which people leap, vault, swing or use other movements to quickly traverse obstacles without the use of equipment.

Full and Hunt continue to explore the interaction between biomechanical abilities and cognition as squirrels learn new gap-leaping strategies.

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