by Sarah DeWeerdt Children with autism may have a subtly different set of bacteria in their gut than their non-autistic siblings, according to unpublished data presented virtually on Tuesday at the 2021 Society for Neuroscience Global Connectome. The prospect that manipulating the microbiome could ease gastrointestinal problems and other autism traits has tantalized many families of autistic children. But studies of the gut microbiome in people with autism are scarce and have shown conflicting results, and mouse studies can be difficult to interpret. For the new work, researchers recruited 111 families that each have two children — one with autism and one without — born within two years of each other and aged 2 to 7 years old. “We tried to be as careful as possible by using a control cohort that were siblings,” says study leader Maude David, assistant professor of microbiology at Oregon State University in Corvallis. This study design helped control for variables such as household environment, pets and other factors that can shape the microbiome, she says. The researchers collected stool samples from the children at three time points, two weeks apart. The repeated sampling reduced the likelihood that short-term shifts in the children’s gut microbiome — due to transient environmental influences, such as day-to-day dietary changes — would skew the results. © 2021 Simons Foundation

Keyword: Autism
Link ID: 27644 - Posted: 01.15.2021

Sophie Balisky, 26, says she struggled with anorexia and bulimia through most of her teens but got help three years ago and was doing great — until COVID hit and she lost her job as a flight attendant. She found herself reverting to old coping patterns in dealing with stressful and uncertain situations. "I was actually quite shocked, I was a bit taken aback, because I consider myself to be quite strong in my coping against my eating tendencies," said Balisky. Advocates for those who struggle with eating disorders say the pandemic is exacerbating the problem — prompting a greater need for community supports. Experts believe the problem is related to the stress, uncertainty and isolation that stems from the pandemic and related-restrictions and say it's not only a problem in the province but around the world. Some eating disorder support groups in Alberta who connect with people of all ages say they have seen a steady rise in demand since the pandemic hit. The Eating Disorder Support Network of Alberta is reporting a 5½ times increase in participants year-over-year between the period from March to the end of August. "So a huge surge through this," said Lauren Berlinguette, executive director of the support network. Another community-based agency that offers support to those who are struggling as well as their families, the Calgary Silver Linings Foundation, says it's experiencing a substantial increase in demand, too. The number of participants in all of its adult programs went from 37 to 64 participants, year-over-year. ©2020 CBC/Radio-Canada.

Keyword: Anorexia & Bulimia
Link ID: 27627 - Posted: 12.15.2020

By Gretchen Reynolds Can exercise help us shed pounds? An interesting new study involving overweight men and women found that working out can help us lose weight, in part by remodeling appetite hormones. But to benefit, the study suggests, we most likely have to exercise a lot — burning at least 3,000 calories a week. In the study, that meant working out six days a week for up to an hour, or around 300 minutes a week. The relationship between working out and our waistlines is famously snarled. The process seems as if it should straightforward: We exercise, expend calories and, if life and metabolisms were just, develop an energy deficit. At that point, we would start to use stored fat to fuel our bodies’ continuing operations, leaving us leaner. But our bodies are not always cooperative. Primed by evolution to maintain energy stores in case of famine, our bodies tend to undermine our attempts to drop pounds. Start working out and your appetite rises, so you consume more calories, compensating for those lost. The upshot, according to many past studies of exercise and weight loss, is that most people who start a new exercise program without also strictly monitoring what they eat do not lose as much weight as they expect — and some pack on pounds. But Kyle Flack, an assistant professor of nutrition at the University of Kentucky, began to wonder a few years ago if this outcome was inevitable. Maybe, he speculated, there was a ceiling to people’s caloric compensations after exercise, meaning that if they upped their exercise hours, they would compensate for fewer of the lost calories and lose weight. © 2020 The New York Times Company

Keyword: Obesity
Link ID: 27617 - Posted: 12.09.2020

by Laura Dattaro In 1983, psychologist Christopher Gillberg posed a provocative question to the readers of the British Journal of Psychiatry: Could autism and anorexia nervosa share underlying causes? Gillberg’s curiosity came in part from his observations of three autistic boys whose female cousins all had the eating disorder, which is characterized by food restrictions, low body weight, an intense fear of gaining weight and a distorted body image. Gillberg, professor of child and adolescent psychiatry at the University of Gothenburg in Sweden, initially suggested that anorexia is the ‘female form of autism.’ Although that idea wasn’t entirely accurate, his suspicions that eating disorders and autism are linked have borne out: People with anorexia are more likely to be autistic than those without it, studies show. There are fewer data demonstrating that autistic people are at particularly high risk for eating disorders, but experts say it’s likely. How often do anorexia and autism overlap? Estimates vary, though most researchers agree that roughly 20 percent of people with anorexia are autistic. Both conditions are rare — about 1 percent of people are autistic and 0.3 percent have anorexia — and most research so far has examined the prevalence of autism in people with anorexia, not the reverse. Among 60 women receiving treatment for an eating disorder at a clinic in the United Kingdom, for example, 14 of them, or 23 percent, scored above the diagnostic cutoff on a test called the Autism Diagnostic Observation Schedule (ADOS). Similarly, about one-third of people with anorexia have been diagnosed with autism, according to a long-running study that has followed 51 people with anorexia and 51 controls in Sweden since the 1980s. © 2020 Simons Foundation

Keyword: Autism; Anorexia & Bulimia
Link ID: 27616 - Posted: 12.09.2020

By Katherine J. Wu For a rodent that resembles the love child of a skunk and a steel wool brush, the African crested rat carries itself with a surprising amount of swagger. The rats “very much have the personality of something that knows it’s poisonous,” says Sara Weinstein, a biologist at the University of Utah and the Smithsonian Conservation Biology Institute who studies them. In sharp contrast to most of their skittish rodent kin, Lophiomys imhausi lumber about with the languidness of porcupines. When cornered, they fluff up the fur along their backs into a tip-frosted mohawk, revealing rows of black-and-white bands that run like racing stripes down their flanks — and, at their center, a thicket of specialized brown hairs with a honeycomb-like texture. Those spongy hairs contain a poison powerful enough to bring an elephant to its knees, and are central to Dr. Weinstein’s recent research, which confirmed ideas about how this rat makes itself so deadly. Give them a chance and African crested rats will take nibbles from the branch of a poison arrow tree. It’s not for nutrition. Instead, they will chew chunks of the plants and spit them back out into their fur, anointing themselves with a form of chemical armor that most likely protects them from predators like hyenas and wild dogs. The ritual transforms the rats into the world’s only known toxic rodents, and ranks them among the few mammals that borrow poisons from plants. Dr. Weinstein’s research, which was published last week in the Journal of Mammalogy, is not the first to document the crested rats’ bizarre behavior. But the new paper adds weight to an idea described nearly a decade ago, and offers an early glimpse into the animals’ social lives. First documented in the scientific literature in 1867, the rarely-glimpsed African crested rat “has captured so much interest for so long,” said Kwasi Wrensford, a behavioral ecologist at the University of California, Berkeley who wasn’t involved in the study. “We’re now just starting to unpack what makes this animal tick.” © 2020 The New York Times Company

Keyword: Neurotoxins; Learning & Memory
Link ID: 27592 - Posted: 11.27.2020

by Peter Hess / Mutations in a top autism gene called SYNGAP1 slow the rate at which zebrafish digest food and pass waste. The findings may explain why some people with SYNGAP1 mutations have gastrointestinal (GI) problems. Researchers presented the unpublished work on Tuesday and Wednesday at the 2020 International SYNGAP1 Scientific Conference, which took place virtually because of the coronavirus pandemic. They also began recruiting people with SYNGAP1 mutations at the meeting for an ongoing study of gut function. “It’s been in the literature, this link between GI symptoms and [autism], for a long time, with not a lot of progress on the mechanisms,” says lead researcher Julia Dallman, associate professor of biology at the University of Miami in Florida, who presented the findings on Wednesday. In the brain, SYNGAP1 functions mainly at synapses, or the junctions between neurons, and helps the cells exchange chemical messages. Mutations in the gene are strongly linked to autism, seizures, intellectual disability and sleep problems. Prompted by families’ anecdotal reports of constipation, reflux and overeating in people with SYNGAP1 mutations, Dallman and her colleagues decided to explore the gene’s role in the gut. The young zebrafish’s transparent skin allowed the researchers to trace the movement of microscopic fluorescent beads — mixed into the fish’s food — through the gut. In this way, they measured how quickly and how strongly the digestive tract moves food and waste. © 2020 Simons Foundation

Keyword: Autism
Link ID: 27590 - Posted: 11.21.2020

The membranes surrounding our brains are in a never-ending battle against deadly infections, as germs constantly try to elude watchful immune cells and sneak past a special protective barrier called the meninges. In a study involving mice and human autopsy tissue, researchers at the National Institutes of Health and Cambridge University have shown that some of these immune cells are trained to fight these infections by first spending time in the gut. “This finding opens a new area of neuroimmunology, showing that gut-educated antibody-producing cells inhabit and defend regions that surround the central nervous system,” said Dorian McGavern, Ph.D., senior investigator at NINDS and co-senior author of the study, which was published in Nature. The central nervous system (CNS) is protected from pathogens both by a three-membrane barrier called the meninges and by immune cells within those membranes. The CNS is also walled off from the rest of the body by specialized blood vessels that are tightly sealed by the blood brain barrier. This is not the case, however, in the dura mater, the outermost layer of the meninges. Blood vessels in this compartment are not sealed, and large venous structures, referred to as the sinuses, carry slow moving blood back to the heart. The combination of slow blood flow and proximity to the brain requires strong immune protection to stop potential infections in their tracks. “The immune system has invested heavily in the dura mater,” said Dr. McGavern. “The venous sinuses within the dura act like drainage bins, and, consequently, are a place where pathogens can accumulate and potentially enter the brain. It makes sense that the immune system would set up camp in this vulnerable area.”

Keyword: Neuroimmunology
Link ID: 27569 - Posted: 11.07.2020

Shawna Williams In Greek mythology, Orpheus descends to the underworld and persuades Hades to allow him to take his dead wife, Eurydice, back to the realm of the living. Hades agrees, but tells Orpheus that he must not look back until he has exited the underworld. Despite the warning, Orpheus glances behind him on his way out to check whether Eurydice is indeed following him—and loses her forever. The story hints at a dark side to curiosity, a drive to seek certain kinds of knowledge even when doing so is risky—and even if the information serves no practical purpose at the time. In fact, the way people pursue information they’re curious about can resemble the drive to attain more tangible rewards such as food—a parallel that hasn’t been lost on scientists. To investigate the apparent similarity between curiosity and hunger, researchers led by Kou Murayama of the University of Reading in the UK recently devised an experiment to compare how the brain processes desires for food and knowledge, and the risks people are willing to take to satisfy those desires. Beginning in 2016, the team recruited 32 volunteers and instructed them not to eat for at least two hours before coming into the lab. After they arrived, the volunteers’ fingers were hooked up to electrodes that could deliver a weak current, and researchers calibrated the level of electricity to what each participant reported was uncomfortable, but not painful. Then, still hooked up to the electrodes, the volunteers were asked to gamble: they viewed either a photo of a food item or a video of a magician performing a trick, followed by a visual depiction of their odds of “winning” that round (which ranged from 1:6 to 5:6). © 1986–2020 The Scientist.

Keyword: Attention; Obesity
Link ID: 27535 - Posted: 10.21.2020

Jon Hamilton Researchers appear to have shown how the brain creates two different kinds of thirst. The process involves two types of brain cells, one that responds to a decline in fluid in our bodies, while the other monitors levels of salt and other minerals, a team reports in the journal Nature. Together, these specialized thirst cells seem to determine whether animals and people crave pure water or something like a sports drink, which contains salt and other minerals. "Our brain can detect these two distinct stimuli with different cell types," says Yuki Oka, a professor of biology at Caltech and the study's lead author. The finding appears to help answer "this question that we've been trying to ask for decades and decades and decades," says Sean Stocker, a professor at the University of Pittsburgh who studies water and salt balance in the body. Stocker was not involved in the study. Oka's research is part of an effort to understand the brain biology underlying behavior that's seen in people and many animals. Article continues after sponsor message For example, people who've just finished a long, sweaty workout often experience a special kind of thirst. "Pure water doesn't do it, right? It's not enough," Oka says. "You need water and salt to recover. And we can easily imagine that under such condition, we crave [a] sport drink." Sports drinks like Gatorade generally include a mix of salt and sugar, as well as water. To understand what triggers this type of thirst, Oka's team studied cells in two regions of mouse brains. Both regions are known to contain neurons involved in the sensation of thirst. © 2020 npr

Keyword: Miscellaneous
Link ID: 27527 - Posted: 10.16.2020

By Bret Stetka The human brain is hardwired to map our surroundings. This trait is called spatial memory—our ability to remember certain locations and where objects are in relation to one another. New findings published today in Scientific Reports suggest that one major feature of our spatial recall is efficiently locating high-calorie, energy-rich food. The study’s authors believe human spatial memory ensured that our hunter-gatherer ancestors could prioritize the location of reliable nutrition, giving them an evolutionary leg up. In the study, researchers at Wageningen University & Research in the Netherlands observed 512 participants follow a fixed path through a room where either eight food samples or eight food-scented cotton pads were placed in different locations. When they arrived at a sample, the participants would taste the food or smell the cotton and rate how much they liked it. Four of the food samples were high-calorie, including brownies and potato chips, and the other four, including cherry tomatoes and apples, were low in calories—diet foods, you might call them. After the taste test, the participants were asked to identify the location of each sample on a map of the room. They were nearly 30 percent more accurate at mapping the high-calorie samples versus the low-calorie ones, regardless of how much they liked those foods or odors. They were also 243 percent more accurate when presented with actual foods, as opposed to the food scents. “Our main takeaway message is that human minds seem to be designed for efficiently locating high-calorie foods in our environment,” says Rachelle de Vries, a Ph.D. candidate in human nutrition and health at Wageningen University and lead author of the new paper. De Vries feels her team’s findings support the idea that locating valuable caloric resources was an important and regularly occurring problem for early humans weathering the climate shifts of the Pleistocene epoch. “Those with a better memory for where and when high-calorie food resources would be available were likely to have a survival—or fitness—advantage,” she explains. © 2020 Scientific American

Keyword: Learning & Memory; Obesity
Link ID: 27518 - Posted: 10.10.2020

By Christa Lesté-Lasserre The bacteria that live in our bodies, particularly our guts, play key roles in immunity and development. But babies born by cesarean section don’t get the rich blend of microbes that come from a vaginal birth—microbes that may help prevent disorders such as asthma and allergies. Now, a study suggests feeding these infants a small amount of their mothers’ feces could “normalize” their gut microbiome—the ecosystem of bacteria, viruses, and fungi in the digestive system—and possibly give their immune systems a healthier start. Newborns’ guts are blank slates: Babies born vaginally get microbes from their mother’s perineum (the area around the vulva and anus), and those born by C-section get them from mom’s skin. Within just a few hours, the differences are stark. For example, Bacteroides and Bifidobacteria bacteria are abundant in the guts of babies born vaginally, but “almost absent in C-section babies,” says Willem de Vos, a microbiome scientist at the University of Helsinki. Because babies born by C-section have higher rates of immune-related disorders later in life, researchers think this early-life bacteria could “prime” the immune system during a critical development period. To lessen the damage, previous studies have “seeded” C-section babies with their mothers’ vaginal microbiota. But when those efforts didn’t seem to do the trick, de Vos and colleagues theorized that vaginally born babies might get their microbes from accidentally ingesting a smidgen of their mother’s stool during the birthing process. So they recruited 17 mothers preparing to give birth via C-section. Three weeks before the women were to give birth, their fecal samples were scanned for pathogens including group B Streptococcus and herpesvirus. © 2020 American Association for the Advancement of Science.

Keyword: Neuroimmunology
Link ID: 27502 - Posted: 10.03.2020

By Nicholas Bakalar Being overweight is linked to an increased risk for premature death, but which part of the body carries the added fat could make a big difference. Extra weight in some places may actually lower the risk. Researchers, writing in BMJ, reviewed 72 prospective studies that included more than two and a half million participants with data on body fat and mortality. They found that central adiposity — a large waist — was consistently associated with a higher risk of all-cause mortality. In pooled data from 50 studies, each four-inch increase in waist size was associated with an 11 percent increased relative risk for premature death. The association was significant after adjusting for smoking, physical activity and alcohol consumption. Waist size is an indicator of the amount of visceral fat, or fat stored in the abdomen around the internal organs. This kind of fat is associated with an increased risk for heart disease, Type 2 diabetes, cancer and Alzheimer’s disease. But increased fat in two places appears to be associated with a lower risk of death. Three studies showed that each two-inch increase in thigh circumference was associated with an 18 percent lower risk of all-cause mortality. In nine studies involving almost 300,000 participants, a four-inch increase in a woman’s hip circumference was associated with a 10 percent lower risk of death. “Thigh size is an indicator of the amount of muscle, which is protective,” said a co-author of the review, Tauseef Ahmad Khan, a postdoctoral fellow at the University of Toronto. “And hip fat is not visceral fat, but subcutaneous fat, which is considered beneficial.” © 2020 The New York Times Company

Keyword: Obesity
Link ID: 27501 - Posted: 10.03.2020

By Lisa Sanders, M.D. The waiter had barely put the plate in front of her when the 46-year-old woman felt the color drain from her face. She was in Fresno, Calif., on a work trip and had come to a restaurant to meet an old friend for dinner. But all of a sudden her stomach dropped — the way it might on a roller-coaster ride. A sudden coolness on her face told her she’d broken out in a sweat. She felt dizzy and a little confused. She saw the alarmed face of her friend and knew she looked as bad as she felt. She excused herself and carefully made her way to the bathroom. She sat in front of the vanity and supported her head on her arms. There was the now-familiar stabbing pain in her stomach. She wasn’t sure how long she stayed like that. Was it 10 minutes? 15? At last she felt as if she could get up. As she hurried to meet her friend at the entrance, she felt the contents of her stomach surging upward. She covered her mouth as vomit shot between her fingers. She lowered her head and bolted through the doorway, trying not to see the horrified faces of the diners. In the parking lot, the rush of stomach contents continued until she was completely empty. Exhausted, she sank into the seat of her friend’s car. She was too sick to go back to her hotel, her friend said. Instead the friend would take her to her house, until she felt better. The next thing the woman remembered was that she was sitting on the floor of her friend’s shower, hot water pounding her back. When she could, she crawled into bed. She slept until late the next morning. She thanked her friend, canceled her morning meetings and later that day headed home to Stockton, Calif. © 2020 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 27498 - Posted: 09.30.2020

By Jane E. Brody Growing rates of obesity among Americans are clear evidence that even the best intentions and strongest motivations are often not enough to help seriously overweight people lose a significant amount of weight and, more important, keep it off. But for those who can overcome fears of surgery and perhaps do battle with recalcitrant insurers, there remains another very successful option that experts say is currently vastly underused. That option is bariatric surgery, an approach that is now simpler, safer and more effective than in its early days in the 1990s. “Only one-half of 1 percent of people eligible for bariatric surgery currently undergo it,” Dr. Anne P. Ehlers, a bariatric surgeon at the University of Michigan, told me. Bariatric surgery is generally considered a treatment option for people with a body mass index (B.M.I.) of 40 or more who failed to lose weight with diet and exercise alone. It is also recommended for those with lesser degrees of obesity — a B.M.I. of 30 to 35 — who have obesity-related medical conditions. The underuse of weight-loss surgery has been largely attributed to “the reluctance of the medical community and patients to accept surgery as a safe, effective and durable treatment of obesity,” other experts at the University of Michigan wrote in JAMA in 2018. They added that patients “may be reluctant to pursue surgical treatment because they may be judged by others for taking the easy way out and not having the willpower to diet and exercise.” © 2020 The New York Times Company

Keyword: Obesity
Link ID: 27495 - Posted: 09.28.2020

By Carolyn Wilke New findings in mice suggest yet another role for gut microbes, even before birth. The microbes residing in a female mouse’s gut help shape the wiring of her offspring’s brain, researchers report September 23 in Nature. While mouse and human development are worlds apart, the study hints at how a mother’s microbiome may have long-term consequences for her offspring. Scientists have previously found links between a mouse mother’s microbiome and her young’s brain and behavior, but many of those studies worked with animals that were stressed (SN: 7/9/18) or sick. Instead, Helen Vuong, a neurobiologist at UCLA, and her colleagues looked at what a mother’s microbial mix normally does for her pups’ brains. The new results point to the influence of specific microbes and the small molecules they produce, called metabolites. “Metabolites from the microbiome of the mother can influence the developing brain of the fetus,” says Cathryn Nagler, an immunologist at the University of Chicago who was not involved with the study. The metabolites do this by reaching a developing pup’s brain where they affect the growth of axons, she says. Axons are the threadlike signal-transmitters of nerve cells. Vuong and her team looked at the brains of fetuses from pregnant mice — some with their usual gut bugs, some raised without microbes and others ridded of their gut bacteria with antibiotics. When a mother’s microbes were missing, fetuses had shorter and fewer axons extending from the brain’s “relay station” to the cortex, Vuong says. These connections are important for processing sensory information. © Society for Science & the Public 2000–2020.

Keyword: Development of the Brain
Link ID: 27483 - Posted: 09.25.2020

By Lisa Sanders, M.D. The pain woke the 52-year-old physician from a dead sleep. It was as if all the muscles in his right leg, from those in the buttock down his thigh to the very bottom of his calf, were on fire. He shifted slightly to see if he could find a more comfortable position. There was a jag of pain, and he almost cried out. He glanced at the clock: 4 a.m. In just three hours he would have to get up. He had a full day of patients to see. Massage didn’t help. He couldn’t get comfortable lying flat, so finally he moved to the living room, to a recliner. Only then, and only by lying completely still, did he manage to get the pain to abate. He drifted off, but never for long. The searing pain in his leg and buttock slowly eased, and by the time his alarm went off, he could stand and walk — though his muscles still ached and he had to baby his right leg, causing a limp. Between patients, he arranged to see his own doctor. He’d had pain off and on in his buttocks, one side or the other, for more than a year. The pain was in the middle of each cheek and was worse when he was sitting and at the end of the day. Walking to and from his car on the way home was brutal. And then, as mysteriously as it came, it would disappear — only to come back a week or two later. When he first told his doctor about his pain, the exam didn’t show much. He was a little tender at the bottom of the bones you sit on, called the ischia. His doctor thought it was ischial bursitis. Between the tips of the ischia and the largest muscles of the buttocks, there are little pads called bursae. Sometimes these pads become inflamed. The man’s doctor recommended stretching exercises for the muscles around the bursae. He did them regularly, though he wasn’t sure they helped. The pain he had that night, though, was different, and a whole lot worse. Again, his doctor couldn’t find much. Maybe it was a kind of nerve pain, like sciatica, the patient suggested. The doctor agreed and ordered an M.R.I. to look for a pinched nerve. The result was normal. © 2020 The New York Times Company

Keyword: Pain & Touch; Neuroimmunology
Link ID: 27474 - Posted: 09.16.2020

By Linda Searing If you’re obese, losing just 5 percent of your weight starts you on the path to better health, but new research finds that losing 13 percent of your weight may make a good-size dent in your chances of developing several unhealthy conditions. For instance, the odds of developing Type 2 diabetes were at least 42 percent lower among obese people who lost that much weight than for those who did not lose weight, according to a report from the European and International Congress on Obesity. The research was based on eight years of data on 552,953 middle-aged adults who were obese and intentionally lost weight (meaning their weight loss did not occur because of an illness). Besides the diabetes effect, losing 13 percent of their weight also made people 25 percent less likely to develop high blood pressure or sleep apnea, and it correlated to a 22 percent risk reduction for high cholesterol and a 20 percent lower risk for osteoarthritis. Obesity, defined as excessive fat accumulation that presents a risk to health, is often determined by a person’s body mass index (BMI), a calculation of body fatness based on weight and height. The simplest way to figure your BMI is to plug your height and weight into an online calculator. A BMI of 30 or above is considered obese. Treatment for obesity usually starts with a modest weight-loss goal of 5 to 10 percent (10 to 20 pounds for someone weighing 200) and includes a change in eating habits and an increase in physical activity.

Keyword: Obesity
Link ID: 27470 - Posted: 09.14.2020

Primatologists observed that different groups of bonobos have different dietary preferences — indicating a form of "culture" among the animals. AILSA CHANG, HOST: Bonobos, like chimpanzees, are one of our closest living relatives. We share about 99% of our DNA. These endangered apes are covered in incredibly black hair. LIRAN SAMUNI: And what's very nice is that they have extremely pink lips, almost as if they put the lipstick on. SACHA PFEIFFER, HOST: That's Liran Samuni, a primatologist at Harvard University. Now her team has discovered that wild bonobos share more than just DNA with humans and chimps. They also appear to share our penchant for culture. SAMUNI: We already had some information about chimpanzees that they have the ability for culture. But it was always this kind of a puzzle about bonobos. CHANG: So for more than four years, the researchers tracked two bonobo groups in the Democratic Republic of Congo, documenting the apes' social interactions and what they hunted. And they found a striking dietary difference. SAMUNI: So we had one group which specialized on the hunting of a small antelope called duiker, while the other bonobo group specialized on the hunting of anomalure, which is a gliding rodent. PFEIFFER: Samuni says think about it in the context of humans. You might have two cultures living near or among each other, but one prefers chicken; the other prefers beef. CHANG: Samuni's colleague at Harvard Martin Surbeck says that's important because it shows that the two groups of bonobos have different preferences despite their overlapping range. © 2020 npr

Keyword: Evolution
Link ID: 27465 - Posted: 09.12.2020

By Veronique Greenwood Hummingbirds live a life of extremes. The flitting creatures famously have the fastest metabolisms among vertebrates, and to fuel their zippy lifestyle, they sometimes drink their own body weight in nectar each day. But the hummingbirds of the Andes in South America take that extreme lifestyle a step further. Not only must they work even harder to hover at altitude, but during chilly nights, they save energy by going into exceptionally deep torpor, a physiological state similar to hibernation in which their body temperature falls by as much as 50 degrees Fahrenheit. Then, as dawn approaches, they start to shiver, sending their temperatures rocketing back up to 96 degrees. It’s an intense process, says Andrew McKechnie, a professor of zoology at the University of Pretoria in South Africa. “You’ve got a bird perching on a branch, whose body temp might be 20 degrees Celsius,” or 68 Fahrenheit, he said. “And it’s cranking out the same amount of heat as when it is hovering in front of a flower.” Now, Dr. McKechnie and colleagues reported on Wednesday in Biology Letters that the body temperatures of Andean hummingbirds in torpor and the amount of time they spend in this suspended animation vary among species, with one particular set of species, particularly numerous in the Andes, tending to get colder and go longer than others. They also report one of the lowest body temperatures ever seen in hummingbirds: just under 38 degrees Fahrenheit. On a trip to the Andes about five years ago, Blair Wolf, a professor of biology at the University of New Mexico and an author of the new paper, and his colleagues captured 26 of the little birds for overnight observation. They measured the hummingbirds’ body temperatures as they roosted for the night and found that almost all of them entered torpor, showing a steep decline in temperature partway through the night. © 2020 The New York Times Company

Keyword: Sleep; Miscellaneous
Link ID: 27463 - Posted: 09.09.2020

By Nicholas Bakalar Being overweight may be linked to an increased risk for dementia. British researchers used data on 6,582 men and women, age 50 and older, who were cognitively healthy at the start of the study. The analysis, in the International Journal of Epidemiology, tracked the population for an average of 11 years, recording incidents of physician-diagnosed dementia. Almost 7 percent of the group developed dementia. Compared with people of normal weight (body mass index between 18.5 and 24.9), overweight people with a B.M.I. of 25 to 29.9 were 27 percent more likely to develop dementia, and the obese, with a B.M.I. of 30 or higher, were 31 percent more likely to become demented. The researchers also found that women with central obesity — a waist size larger than 34.6 inches — were 39 percent more likely to develop dementia than those with normal waist size. Fat around the middle was not associated with a higher dementia risk in men. The study controlled for age, sex, APOE4 (a gene known to increase the risk of Alzheimer’s disease, the most common form of dementia), education, marital status, smoking and other known dementia risks. The lead author, Yixuan Ma, a student at University College London, said that this observational study does not prove cause and effect. “Being overweight is just a risk,” she said. “It doesn’t mean that an overweight person will necessarily get dementia. But for many reasons, it’s good to maintain a normal weight and engage in vigorous physical activity over a lifetime.” © 2020 The New York Times Company

Keyword: Alzheimers; Obesity
Link ID: 27449 - Posted: 09.05.2020