Brain

Motility is an essential property of many cell types, and is driven by molecular motors. A Ludwig-Maximilians-Universitaet (LMU)in M has now discovered that the motor protein myosin VI contributes directly to the deformation of the cell membrane, as required for locomotion or endocytosis.

Membranes composed of a lipid bilayer define the outer surface of nucleated cells (the plasma membrane) and delimit the vital organelles within these cells, such as mitochondria and nuclei. The membrane curvature determines the three-dimensional form of these structures, and is therefore a key factor in their respective functions. Furthermore, the ability to actively deform membranes is indispensable for many cellular processes. Using a combination of experimental and theoretical approaches, LMU research groups led by Prof. Claudia Veigel (Biomedical Center) and Prof. Erwin Frey (Arnold Sommerfeld Center for Theoretical Physics), who are also members of the Munich Center for Nanoscience (CeNS), have now demonstrated that proteins called molecular motors are directly involved in the control of membrane deformation. The new findings appear in the online journal Nature Communications.

Formation and dynamics of the membrane curvature is the result of a complex interplay between many different proteins, in which the cytoskeleton - with which molecular motors interact - plays a significant part. The motor interactions enable the cell's internal skeleton to be dynamically broken down locally, and reassembled into new configurations. These processes in turn indirectly exert forces onto the cytoplasmic membrane. The motor proteins move along the various filament systems, which together comprise the cytoskeleton, transporting molecular cargos to their destinations. However, the motor proteins themselves can also act as signaling molecules. "We have now discovered a completely new type of function for one particular motor protein, called myosin VI: this motor directly engages with the components of the plasma membrane and dynamically alters its shape," says Laeschkir Würthner, joint first author of the study.

"Using fluorescent markers and super-resolution fluorescence microscopy we were able to experimentally confirm that myosin VI binds directly to the membrane. Combining these experiments with triangular-shaped gold nano-particles we also found that this interaction occurs in a remarkably selective and highly cooperative fashion - specifically at locations where the membrane curvature adopts a saddle shape. The binding sites appear at nano-pores, which are induced by thermal fluctuations. When myosin VI molecules dock at these sites, they do so in a dynamically variable, flower-like pattern, which can reach diameters of several micrometers around each pore. In our experiments, the circumference of these 'flowers' grows at a constant rate, which is directly proportional to the concentration of myosin available," Veigel explains.

The authors of the study propose that this newly discovered function of myosin-based motors is involved in important cellular processes, such as endocytosis and the formation of membrane protrusions. "We have also developed a quantitative theoretical model, which correctly describes the protein-membrane interaction and the resulting dynamics of membrane morphology," says Frey. "We believe that, in the near future, our new assay and the model that underpins it will help us to uncover other mechanisms of membrane deformation, and elucidate the universal role of membrane curvature in cellular function."

COLUMBUS, Ohio - When preschool teachers read books in their classrooms, the questions they ask play a key role in how much children learn, research has shown.

But a new study that involved observing teachers during class story times found that they asked few questions - and those that they did ask were usually too simple.

Only 24 percent of what teachers said outside of reading the text were questions, the results found. And the kids answered those questions correctly 85 percent of the time.

"When kids get 85 percent of the questions right, that means the questions the teacher is asking are too easy," said Laura Justice, co-author of the study and professor of educational psychology at The Ohio State University.

"We don't want to ask all difficult questions. But we should be coaxing children along cognitively and linguistically by occasionally offering challenging questions."

While this study was done with teachers, the same lessons apply for parents. Previous research suggests that most parents don't ask any questions at all when they're reading with their children, according to Justice.

The study appears online in the journal Early Childhood Research Quarterly and will be published in a future print edition.

Participants in the study were 96 prekindergarten and kindergarten teachers at schools in the Midwest and South and their students, said Justice, who is executive director of The Crane Center for Early Childhood Research and Policy at Ohio State.

The teachers were videotaped in one class while reading the 25-page book Kingdom of Friends to their students. The book is about two friends who argue at playtime but learn how to resolve their problems.

Researchers transcribed all talk during the reading session, including both teachers and children.

The researchers recorded 5,207 questions asked by teachers and 3,469 child responses.

About 52 percent of the questions asked by teachers were yes-no type questions, such as "Does he look happy?" As expected, most of them resulted in one-word answers from children.

The other 48 percent of questions included "what" and "why" questions like "What did he do?" and "Why do you say 'friends'?"

This also included what the researchers called "how-procedural" questions, like "How did they become friends again?"

"When the teachers asked these more sophisticated how-procedural questions, the children would give more elaborate and complex answers," Justice said. "Those are the kind of questions we need more of."

Asking these more sophisticated and difficult questions means that children are more likely to give wrong or inappropriate answers, she said. But that's okay.

"There should be teachable moments where teachers can help their students learn something new. You have a conversation that is conceptually challenging for the child, because that is going to push their development forward," Justice said.

Some experts recommend that 60 to 70 percent of shared reading conversations should be easy, but 30 to 40 percent should challenge children to learn new concepts.

The fact that 85 percent of children's responses in this study were correct suggests that they are not being challenged enough, Justice said.

Story time should include lots of questions, including ones that allow children to stretch their language and thinking abilities, she said.

For example, when parents or teachers are reading a new book they could ask the child "How do you think this book will end?"

"You can see how a question like that is going to evoke a complex response," Justice said.

"With some practice and reflection, we can change how we talk with children during shared reading and help them develop stronger language and reading skills."

Osaka, Japan -- Stress affects both mental and physical health. Although stress is known as one of the major risk factors of health disorders in modern society, a biomarker of stress has not yet been well established. In a study published in the Journal of Investigative Medicine, researchers from Osaka University reported a unique association between stress and serum levels of α-Klotho (αKl).

αKl was originally established as an anti-aging gene and is reported to relate with various diseases. The researchers have previously reported that smoking, which is known as a stress factor, increased serum levels of soluble αKl (sαKl) (Scientific Reports, 2015). In the study, association between stress and serum levels of sαKl were evaluated, by using the Kessler Screening Scale for Psychological Distress (K6);, which is widely used to screen mental health problems.

As the study subjects, apparently healthy individuals who had never smoked were randomly chosen. Physical parameters, biochemical parameters, and information regarding the lifestyle were obtained from all subjects.

Serum levels of sαKl were significantly increased in subjects who reported poor stress management. In addition, sαKl levels were significantly increased in subjects who reported that they did not feel relaxed after sleep (Figure 1). These results suggest that stress management and sleeping conditions influenced the serum levels of sαKl. Moreover, serum levels of sαKl showed the same tendency as the K6 score in terms of the relationship between stress management and sleeping conditions.

"Although the number of people who feel stressed has been increasing, a useful objective parameter of stress is still unknown. We focused on the serum levels of sαKl as a possible objective biomarker of stress, and found an interesting association between stress and sαKl levels," says researcher Kaori Nakanishi of Osaka University. "From the study, it is suggested that increased serum levels of sαKl might be predicting the stressed condition. We are speculating that serum levels of sαKl could be a predictive factor of stress."

Researchers at the University of Turku found that the presence of a maternal sister was positively and significantly associated with annual female reproduction in a population of working elephants in Myanmar. In addition, an age-specific effect was found: young females were more sensitive to the presence of sisters and even more likely to reproduce when living near a sister.

- We studied Asian elephants working in the teak industry in Myanmar. The elephants are released to the forest for the evenings and nights and other holiday periods, when they can move around freely, eat and meet other elephants. Our study compared the annual reproductive rate of females living with and without maternal sisters. We found that young females, in particular, are more likely to reproduce in a given year when living near a maternal sister, and this effect was strongest when the sister was 0-5 years younger, says Emily Lynch, lead author of the study.

The authors claim that while the proximate mechanism driving enhanced reproduction may be related to improved health generated by sociality, such age-related benefits suggest other factors may be at play.

- Especially because the parenting experience may be crucial for successfully rearing offspring, young, inexperienced females are at a disadvantage and assistance from relatives may therefore be particularly valuable to young females.

Relationships among females have an important evolutionary basis

- Although there is widespread evidence that individuals prefer relatives over non-relatives as social partners, little is known about the potential benefits associated with living with kin in long-lived, social mammals, Lynch says.

Because elephants are highly social and matrilocal animals, meaning that females remain in their natal group with female relatives throughout their lifetime, it is likely that social relationships provide varying benefits across a female's lifetime.

- Sociality is known to improve both physical and mental health in humans, for example. This study shows that in elephants socialising with female relatives improves the changes of female reproduction. However, the motivation to nurture relationships with female relatives is age-dependent, which, in turn, results in a variety of fitness benefits. Overall, the study suggests that relationships among female kin are of evolutionary importance in long-lived social mammals, Lynch says.

These results build on previous work on this population, in which it was discovered that the presence of a maternal grandmother is associated with improved grand calf survival and increased reproductive output of the daughter, and this effect was particularly strong among young daughters.

- This study is particularly exciting because we were able to access information on elephant reproduction across several generations to effectively examine the evolutionary consequences of female social relationships with kin. Access to such longitudinal data on a long-lived, social mammal is rare and we are now able to have a better grasp of the importance of living with relatives in elephants, Lynch says.

Researchers from the Human Nutrition Unit of the Universitat Rovira i Virgili (Tarragona/Spain) and the Pere Virgili Health Research Institute (IISPV) have found that consuming 60 grams of nuts a day improves sexual function. They have conducted the first nutritional intervention study with healthy participants of reproductive age in order to determine if regular consumption of nuts has any effect on sexual function. The analysis forms part of the FERTINUTS project, which has been created to assess the effects of regularly consuming nuts on the quality of semen.

Sample and results

The prevalence of erectile and sexual dysfunction is thought to affect 2% of men under the age of 40 years, around 52% of men aged 40 to 70 years and more than 85% of men over 80. The risk factors associated with sexual and erectile dysfunction are smoking, excessive alcohol consumption, a lack of physical exercise, stress and an unhealthy diet.

In a previous study, the same research group described how certain nuts (walnuts, hazelnuts and almonds) improved sperm quality, although there were still no studies demonstrating the positive effects of these nuts on sexual function.

Their most recent study was conducted on 83 individuals who were following a western diet (poor in fruit and vegetables and rich in animal fats). The participants were divided into two groups: one group continued to follow their normal western diet over 14 weeks while the other complimented their diet with a daily intake of 60 grams of walnuts, hazelnuts and almonds. At the end of the study period, each individual completed an internationally validated questionnaire known as the IIEF-15 containing 15 questions on sexual function.

The findings show that adding walnuts, hazelnuts and almonds to an unhealthy western diet can improve sexual desire and orgasm quality. The researchers also pointed out that further studies involving more participants are needed to confirm these results and to determine how these benefits arise.

The study was published in the scientific journal Nutrients and was written by the post-doctoral researcher Albert Salas-Huetos (currently working at the University of Utah) in collaboration with the URV's Human Nutrition Unit and CIBERobn Network ), led by URV professor Jordi Salas-Salvadó.

Scientists have completed the first study of immune and genetic stability among a colony of penguins living in a remote corner of southern Antarctica.

Researchers examined erythrocyte nuclear abnormality (ENA) and white blood cell (WBC) levels in Adélie penguins breeding at Edmonson Point.

Through blood tests conducted on 19 adult penguins, they found quantities of cell types associated with future cell death, genomic instability or cancer development.

The study's findings will act as baseline data for future studies into the health status of breeding penguins and how they are responding to environmental changes.
Edmonson Point is an Antarctic Specially Protected Area (ASPA) in the Ross Sea, which in turn is home to 38% of the global population of Adélie penguin.

The Adélie is considered a keystone species of the Antarctic environment so it is considered mandatory to address the current health status of population living in this territory to prove the efficacy of the protected area and to monitor any potential impact in the future.

The research was undertaken through a collaboration between the University of Siena and the University of Plymouth, as part of an Erasmus student exchange between the universities. It was funded by the Italian National Antarctic Research Programme.

Dr Silvia Olmastroni, from the University of Siena and the Italian National Antarctic Museum, led the research along with University of Siena colleague Dr Ilaria Corsi. She said: "Antarctic seabirds are well adapted to extreme environments and often deal with sub-optimal conditions and severe environmental stress. Climate change, pollution, habitat loss and increasing human presence can all significantly affect organism's health status and long-term survival. For that reason, it is crucial to have this understanding of a species' immune and genetic system so that any changes can be identified at the earliest opportunity."

It is well known that climate change is affecting the bioavailability of toxic contaminants in the wildlife of Antarctica, leading to changes in organism homeostasis and other physiological defence mechanisms.

This means that during a penguin's lifetime, contaminant exposure - both in its breeding and feeding habitats - may vary according to the ecosystem changes.

However, in comparison with other Antarctic territories, the Ross Sea is still considered a pristine area even though human pressure has increased significantly in the last 20 years due to growth of fisheries, tourism and number of scientific bases.

The current research showed that ENA and WBC levels are consistent with studies of other Adelie penguin colonies across the Antarctic peninsula.

However heterophil:leukocyte ratios, which can represent an evolutionary response to natural stressors, was higher in the Edmonson Point colony than in other Adélie penguin populations.

Awadhesh Jha, Professor of Ecotoxicology at the University of Plymouth, added: "It is difficult at this stage to connect what we found in this study to any particular contamination or stress sources. However, over coming decades and beyond, environmental stressors and an increase in associated impacts on wildlife are expected to grow in Antarctica. This information provides us with a series of useful biological indicators for future monitoring and conservation studies to assess potential impact on population and ecosystem health in changing environments."

Whether it is pigeons in the air, electrons in a telegraph wire, radio waves from a cell phone or single photons in an optical fiber, in standard communication, there is always a particle or wave involved in the information exchange between two parties; say Alice and Bob. However, in quantum mechanics, one can send information from Alice to Bob while the particle or wave involved in this information exchange travels from Bob to Alice.

In an international collaboration led by Philip Walther, scientist from the University of Vienna teamed up with the University of Cambridge and the Massachusetts Institute of Technology to implement a new counterfactual communication protocol. In standard photonic communication, the information is encoded in single photons; thus, the information and the single photons travel in the same direction. However, in counterfactual communication there is no carrier found travelling in the same direction as the message. In this implementation, single photons would travel from Alice to Bob while information would travel from Bob to Alice.

What carries the message then? Even before receiving the single photon, Bob prepares his setup according to the information bit that he wants to send, either 0 or 1. In this way, he sends the single photon back if he wants to send a bit 1 or keeps the photon in his laboratory if he wishes to send a bit 0. Counterintuitively, the Zeno effect, which was first discovered by cryptanalyst Alan Turing, enables Bob to send the photon back without actually interacting with it. Alice will then interpret Bob's message by observing whether the sent photon is returned or not. Thus, the presence and the absence of single photons is enough to encode any message.

In previous counterfactual communication protocols, there remains some uncertainty as to whether Bob interacted with the photons or not. In this new implementation the two main drawbacks of earlier implementations, weak trace and postselection, have now been completely overcome. "In our implementation, there is no trace of the photon travelling in the same direction as the information and we are able to compensate the message errors without discarding information bits." says I. Alonso Calafell, one of the authors from the publication.

By combining an integrated photonic platform built at MIT, together with a novel theoretical proposal developed at the University of Cambridge, scientist from the University of Vienna contradicted a crucial premise of communication theory: that a message is always carried by physical particles or waves.

Washington, DC, July 23, 2019 - Hoarding can often be a debilitating problem for adults and is often associated with poorer mental health functioning and response to treatment. For children however, that may not be the case. A new study in the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP), published by Elsevier, reveals that cognitive-behavioral therapy (CBT) used to treat obsessive-compulsive disorder (OCD) can be successful for youth with hoarding symptoms.

Hoarding has historically been closely associated with OCD but is now considered in its own category in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and is a phenomenon that is increasingly being discussed in the media.

"While evidence in adults suggests that hoarding can be debilitating and interfere with a patient's ability to benefit from CBT, we found that the presence of hoarding symptoms does not interfere with treatment response to CBT for pediatric OCD," said lead author Michelle Rozenman, PhD, Assistant Professor at the University of Denver, Denver, CO, and Adjunct Assistant Professor at the UCLA Semel Institute for Neuroscience & Human Behavior, Los Angeles, CA, USA.

"Pediatric hoarding symptoms are prevalent, as nearly half of all youth affected by OCD also experience hoarding symptoms. Given the contrast between our data and studies of hoarding in adulthood that suggest poorer CBT treatment response, clinicians should assess for hoarding in their pediatric OCD patients in order to address these symptoms prior to adulthood when symptoms may worsen and interfere with an individual's functioning," Dr. Rozenman added.

The findings are based on data from children and adolescents presenting for services at the UCLA Child OCD, Anxiety, and Tic Disorders Program, a university-based specialty research and clinical program directed by John Piacentini, PhD.

A cohort of 215 children and adolescents between the ages of 7 to 17 who received a primary diagnosis of OCD were enrolled. The authors found that a substantial proportion of OCD-affected youth (43 percent) reported hoarding symptoms.

Evidence-based clinical interviews were conducted to determine OCD and other psychiatric diagnoses, OCD symptom severity and impairment, and presence of hoarding symptoms. A subsample of 134 youth were enrolled in research clinical trials where they received 12 sessions of CBT, with OCD symptom severity and impairment also assessed at the end of treatment.

OCD-affected youth with hoarding symptoms had a higher number of concurrent psychiatric diagnoses on average than those without hoarding symptoms (1.5 vs. 0.78). However, OCD-affected youth with hoarding symptoms did not differ from those without hoarding symptoms in regard to OCD symptom severity and impairment.

The investigators also found that the proportion of OCD-affected youth with hoarding symptoms did not differ from those without hoarding in their treatment response to CBT (50 percent vs. 60 percent), or in improvements in OCD symptom severity.

Importantly, age did not influence any of these relationships, suggesting that the findings apply across childhood and adolescence.

There's no organ system in the body that does as much for humans as roots do for plants. Part anchor and part mouth, a plant's root system architecture is critical to its success. But the process of growing new roots is costly to a plant, and there can be diminishing returns.

It's not clear-cut how a plant determines enough is enough and stops making roots. New research from Washington University in St. Louis identifies a cellular transporter that links two of the most powerful hormones in plant development -- auxin and cytokinin -- and shows how they are involved in putting the brakes on root initiation and progression. The new work by Lucia Strader, associate professor of biology in Arts & Sciences, and her co-authors is published July 18 in the journal Developmental Cell.

"This is exciting because for a long time, we've known that auxin and cytokinin have opposing roles, but the direct links between how one of them might affect the other in lateral root production was not well understood," Strader said.

Lateral roots are the roots that branch out horizontally like fingers stretching out to the side. They make up the majority of root mass.

"Our data suggests that one of the ways that cytokinin can decrease lateral root production is by increasing the levels of this transporter to limit contributions of this particular auxin precursor to active auxin," she said.

Pumping and releasing the brakes

The plant hormone auxin controls almost every aspect of plant growth and development, including stimulating root growth overall. Previous research has shown that another important hormone called cytokinin has a limiting effect -- controlling the locations where new lateral roots could possibly sprout, and ensuring sufficient spacing between neighboring roots.

Until now, however, scientists have not identified how these hormones "talk" to each other.

Working with the model plant Arabidopsis thaliana, Strader decoded a key to this conversation.

Strader discovered that a cellular transporter she dubbed TOB1 can stash away an auxin precursor by moving it into a vacuole, an organ in the plant cell that acts as a kind of storage space or holding pen. That action prevents the precursor, which is called IBA, from metabolizing into full-fledged auxin -- with all of its root-promoting capabilities.

"If TOB1 is the brake, cytokinin is the foot on the brake," Strader said. "It's the thing that's saying how much TOB1 should be around to dampen down on lateral root production."

Plants can increase or relax the hold as needed. Strader and her team used gene modification techniques to eliminate the transporter, and saw dramatic effects in the next generation of plants.

"When you get rid of this transporter, you have about double the number of lateral roots as the wild type, without sacrificing root depth," Strader said.

Strader also repeated certain of her experiments with a yeast and frog oocytes (with the help of Wolf B. Frommer of Heinrich Heine University in Düsseldorf, Germany) instead of a plant, and found TOB1 to be just as effective as a transporter for IBA in these systems.

Slow but steady may be better for plants

Strader's research shows how she and her collaborators started with an unbiased genetic screen and ended up identifying a critical regulator of an aspect of plant development that often gets ignored -- one that's not readily visible, because roots are underground.

And Arabidopsis roots are tiny. At two weeks old, its leaves are much smaller than a dime, and its roots are thread-like and transparent. To bring the process of lateral root production into the daylight, Strader reached out for help from Christopher Topp, a principal investigator at the Danforth Plant Sciences Center. Topp used a non-destructive technique to capture the first ever three-dimensional serial images of developing Arabidopsis plants in medium -- a feat that is remarkable, given how much research has been conducted with this model plant.

What they uncovered is useful because the molecular mechanisms regulating root architecture are critically understudied.

Understanding why and how plants make different types of root architectures can help to develop plants that better cope with distinct soil conditions and environments. In follow-on work, Strader has already begun to look at how TOB1 mutants respond differently in soils with different micronutrients.

"When you get rid of your brakes, you just go crazy," Strader said. "In the beginning, this looks like a good agricultural trait. You want all of your plants in the soil to explore more soil to get more nutrients, to get more roots to the water.

"But, if you don't ever have a brake, you waste your time making more and more of these," she said. "Probably at some stage in the plant's life cycle, this slow but steady approach is better than the all-out, 'let's make lateral roots everywhere,' one."

Despite believing that self-care is a vitally important part of health and overall well-being, many physicians overlook their own self-care, according to a new survey released today, conducted by The Harris Poll on behalf of Samueli Integrative Health Programs. Lack of time, job demands, family demands, being too tired and burnout are the most common reasons for not practicing their desired amount of self-care.

"Doctors seem to understand the physical as well as mental, emotional and social value of engaging in self-care, and that's encouraging because we are in a powerful position to help promote self-care among our patients," said Wayne Jonas, MD, executive director of Samueli Integrative Health Programs. "But when it comes to their own self-care, many physicians are falling short, which perhaps is one reason for the clinician burnout crisis facing our country."

The survey - involving more than 300 family medicine and internal medicine physicians as well as more than 1,000 U.S. adults ages 18 and older - found that although 80 percent of physicians say practicing self-care is "very important" to them personally, only 57 percent practice it "often" and about one-third (36%) do so only "sometimes." The survey was conducted online by The Harris Poll on behalf of Samueli Integrative Health Programs in May and June 2019.

Lack of time is the primary reason physicians say they aren't able to practice their desired amount of self-care (72%). Other barriers include mounting job demands (59%) and burnout (25%). Additionally, almost half of physicians (45%) say family demands interfere with their ability to practice self-care, and 20 percent say they feel guilty taking time for themselves.

"Physicians are under an exorbitant amount of stress. The way that our health system is set up requires physicians to spend more time on administrative duties and less time with patients and themselves," said Jonas. "This mounting pressure on physicians will only get worse. We need to fix the system to allow physicians breathing room to care for themselves as much as they care for their patients."

However, nearly all physicians (98%) believe self-care positively impacts mental health and 97 percent believe it has a positive impact on physical health. Further, about 9 in 10 physicians (96%) agree that self-care should be considered an essential part of overall health.

When physicians do engage in self-care, 87 percent say it is to maintain or improve their physical health, 83 percent to reduce stress and 82 percent to maintain or improve their mental health. Common self-care practices among physicians include exercise (83%), eating healthy foods (81%), maintaining healthy relationships (77%), working on personal development (76%), engaging in stress relief activities like reading or meditating (70%) and getting enough sleep (70%).

Being able to walk outside for several blocks at a leisurely pace plays an important role in living a vibrant, healthy life. Walking short distances allows you to get the physical activity you need, live independently, go shopping, access health care, and engage in a social life.

Being able to walk at even a slow speed is essential to all these benefits--but walking too slowly may foreshadow future problems that could prevent you from being fully mobile.

Until now, there has been no ideal way for healthcare providers to measure walking ability, since it involves more than just walking speed. It also is about how you deal with your environment (such as uneven pavement) and demands on your attention (such as traffic, other pedestrians, and street crossings).

In a new study, researchers assessed ways to measure complex walking tasks to learn more about early, subtle changes in walking. Their study was published in the Journal of the American Geriatrics Society.

In their study, the researchers examined whether performance on complex walking tasks involving both physical and mental challenges predicted a higher risk for an inability to walk one-quarter mile (roughly four blocks). The researchers suspected that these complex walking tasks would be more strongly tied to the risk for mobility problems than simple walking.

The researchers studied information from the Health Aging and Body Composition (Health ABC) study, which enrolled black and white adults in Pittsburgh and Memphis from 1997 to 1998. The participants were 70 to 79 years old when they entered the study, and they had no difficulty walking a quarter mile or climbing 10 steps without resting.

In the study, participants walked on several different paths and were given several different challenges to measure their walking speed and their ability to cope with mental and physical tasks at the same time. Researchers then followed up with participants every six months to see if they had any difficulty walking one-quarter mile due to a health or physical problem.

Participants reported any mobility problems or disabilities every year at in-person visits. By the end of the eight-year follow-up, more than half of the participants had developed mobility disability, meaning they were unable to walk one-quarter mile. Almost 40 percent had developed chronic mobility disability that lasted at least two years.

Participants who reported having mobility disability were more likely to be female, have diabetes, be obese, have knee pain, and experience breathing difficulty. They also had more symptoms of depression.

The researchers concluded that slow walking speed under both usual-pace and complex conditions was associated with greater risk for developing mobility disability over the next eight years.

They also concluded that measuring your simple walking speed in the healthcare provider's office may be enough for your provider to learn whether you might be at risk for future mobility problems.

Climate change can threaten species and extinctions can impact ecosystem health. It is therefore of vital importance to assess to which degree animals can respond to changing environmental conditions - for example by shifting the timing of breeding - and whether these shifts enable the persistence of populations in the long run. To answer these questions an international team of 64 researchers led by Viktoriia Radchuk, Alexandre Courtiol and Stephanie Kramer-Schadt from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) evaluated more than 10,000 published scientific studies. The results of their analysis are worrisome: Although animals do commonly respond to climate change, such responses are in general insufficient to cope with the rapid pace of rising temperatures and sometimes go in wrong directions. The results are published in the scientific journal "Nature Communications".

In wildlife, the most commonly observed response to climate change is an alteration in the timing of biological events such as hibernation, reproduction or migration (phenological traits). Changes in body size, body mass or other morphological traits have also been associated with climate change, but - as confirmed by this study - show no systematic pattern. The researchers extracted relevant information from the scientific literature to relate changes in climate over the years to possible changes in phenological and morphological traits. Next, they evaluated whether observed trait changes were associated with higher survival or an increased number of offspring. "Our research focused on birds because complete data on other groups were scarce", says lead author Viktoriia Radchuk (Leibniz-IZW). She adds: "We demonstrate that in temperate regions, the rising temperatures are associated with the shift of the timing of biological events to earlier dates."

Co-author Steven Beissinger (Professor at the University of California in Berkeley) says "This suggests that species could stay in their warming habitat, as long as they change fast enough to cope with climate change." However, senior author Alexandre Courtiol (Leibniz-IZW) adds "This is unlikely to be the case because even populations undergoing adaptive change do so at a pace that does not guarantee their persistence". Co-author Thomas Reed (senior lecturer at University College Cork, Ireland) explains "These results were obtained by comparing the observed response to climate change with the one expected if a population would be able to adjust their traits so to track the climate change perfectly".

Even more worrisome is the fact that the data analysed included predominantly common and abundant species such as the great tit (Parus major), the European pied flycatcher (Ficedula hypoleuca) or the common magpie (Pica pica) which are known to cope with climate change relatively well. "Adaptive responses among rare or endangered species remain to be analysed. We fear that the forecasts of population persistence for such species of conservation concern will be even more pessimistic" concludes Stephanie Kramer-Schadt (Head of the Department of Ecological Dynamics, Leibniz-IZW). The scientists hope that their analysis and the assembled datasets will stimulate research on the resilience of animal populations in the face of global change and contribute to a better predictive framework to assist future conservation management actions.

Repetitive knee stress and lack of rest are major causes of ACL failure according to new research.

The peak age for ACL failures is 14. People in mid-20s suffering from osteoarthritis and other chronic health conditions.

Australia has the highest reported rates of ACL injuries and reconstructions per capita in the world.

Repetitive knee stress and failure to accommodate sufficient rest between periods of strenuous exercise may be key factors behind the rapid rise in anterior cruciate ligament (ACL) injuries in world sport, a new international study has found.

While it is already well recognised that a single supramaximal force can cause ACL failure, it has been assumed that sub-maximal forces could not cause ACL failure.

But this world-first research, published in the American Journal of Sports Medicine, has found that a series of submaximal forces can indeed cause damage to accrue in the ACL, in a process called low-cycle material fatigue, and that same damage is found in ACLs which have failed.

The problem of ACL injuries is described by researchers as a 'ticking time bomb' because of the number of these injuries and the degeneration in the knee that they can cause.

This study provides an important new mechanism beyond the common view that ACL failures occur due to a single sudden or forceful movement and/or a lack of neuromuscular training.

Above all, researchers have shown that competitive sporting environments are producing generations of athletes that risk developing knee osteoarthritis no matter how they are treated.

Academics from the University of Michigan and Monash University have argued that material fatigue is behind the steep rise in 'non-contact' ACL injuries. Nearly three-quarters of ACL injuries are 'non-contact' failures, even in contact sports like Australian Rules Football and the American National Football League (NFL).

"ACL injuries are the number one cause of time spent away from NFL practice and play, with recovery periods up to 12 months long," said lead researcher and orthopaedic surgeon, Dr Edward Wojtys, who has been studying this issue for more than 30 years.

"Incredibly, we're seeing that the peak age for ACL failures is 14. This can lead to people in the mid-20s suffering from osteoarthritis and other chronic health conditions later in life, such as obesity and cardiovascular disease. Female athletes are at most risk."

Led by Dr Wojtys and biomechanical engineer Professor James Ashton-Miller, both from the University of Michigan, the team tested one healthy knee from each of seven adult cadavers in a controlled laboratory study using a purpose-built machine, which took three years to develop.

Each knee was subjected to repetitive pivot landings loaded under four-times body weight - approximately the weight under which someone jumps and lands - which twisted the knee to cause ACL failure within 100 landings.

What they couldn't see was what was happening to the ACL itself inside the knee, especially near the thigh bone where the team knew most ACLs fail.

Professor Mark Banaszak Holl, Head of Chemical Engineering at Monash University, joined this project in order to answer that question - along with two PhD students Jinhee Kim and Junjie Chen.

Using atomic force microscopy to characterise the ACL collagen at the nanometre scale, or one billionth of a metre, Professor Banaszak Holl and his team were able to identify a consistent unravelling of the molecular structure of the ACL's collagen in the injured cadaver knees.

Professor Banaszak Holl said the results of this latest research throw into serious doubt the argument that most ACL injuries are caused by single force events. This could lead to different ways of managing athletes of all ages and levels.

"What we found from the tested cadaver knees was chemical and structural evidence of micro-damage of the ACL femoral enthesis, which is where the ligament attaches to the thigh bone and where the ACL typically tears," he said.

"These results were consistent with ACLs removed from patients undergoing knee reconstructions.

"The new hope is that a change in athlete training and preparation could then limit the number of risky submaximal loading cycles. Allowing sufficient time for soft tissue recovery during or between training bouts could prevent the accumulation of ACL micro-damage and eventual failure.

"Now that we know the nature of the problem and the structural changes occurring, we can look for non-invasive ways of determining who is predisposed to injuring their ACL."

ACL injuries are a global trend with more than two million people having surgery to repair their torn ligaments each year. Australia currently has the highest reported rates of ACL injuries and reconstructions per capita in the world.

But this isn't just happening at the elite level. According to a study published last year in the Medical Journal of Australia, the number of young Australians requiring knee reconstructions in the previous 15 years has jumped by 70%. The greatest increase was in children under 14, with some as young as eight going in for surgery.

"We have to ask ourselves the question; is more always better?" Professor Ashton-Miller said.

"Until we have more answers, it's not worth pushing our bodies and ligaments to the extreme because of the potential long-term damage it can cause. There are limits to what the human body can tolerate. Being more selective about the training that is done is clearly warranted.

"Fewer repetitions known to significantly stress the ACL will ultimately lead to fewer injuries. This should be the main focus of sporting clubs and athletes of all ages and levels of professionalism."

DALLAS (SMU) -College students in Texas who graduated from public universities with a bachelor's degree had, on average, student loan debts that equaled 74 percent of what they earned in their first-year wages, according to a new study from SMU (Southern Methodist University).

The study, which looked at students who started college between 2004 and 2008, also shows that black and Latinx students are predicted to borrow larger amounts of college debt than white students compared to what they'll make in their first job.

The findings suggest that if public universities try to meet the goals of a Texas initiative designed to increase attainment and reduce student debt burdens, the institutions may inadvertently be discouraged from educating historically underserved students.

"Even when controlling for prior income, parental education, choice of major and the time it took to get their degree, historically underserved students are predicted to have higher debt-to-income ratios," said Dominique J. Baker, author of the study and assistant professor of education policy at SMU's Simmons School of Education and Human Development. "This means that any sanctions associated with a policy like the 'strategic goal' in Texas would likely punish state institutions simply for educating students who are predicted to have higher debt-to-income ratios."

Baker's study is the first to investigate the debt-to-income ratio in Texas since the state created the 60x30TX strategic plan. The plan calls for increased completion of undergraduate programs in shorter periods of time, as well as efforts to keep undergraduate student debt at or below 60 percent of first-year wages by 2030.

Baker's study only focuses on students who earned a bachelor's degree. The 60x30TX plan also includes students who earn a credential or associate's degree who have smaller debt-to-income ratios than bachelor's degree recipients.

The findings, which were recently published in AERA Open, suggest that the state of Texas may find it difficult to maintain the 60 percent goal given the demographic and borrowing trends in the state.

On average, students who graduated with a bachelor's degree after attending a public university had an average $25,794 of undergraduate loan debt. That number jumped to $33,255 when loans held by parents were also included.

Yet, students earned approximately $34,132 during their first year after earning a degree, meaning that the average student's debt-to-income was 74 percent, according to the study. If you factor in the amount that parents took out in loans for their child's college education, the average debt-to-income ratio was closer to 92 percent.

In addition, the study found that black students, on average, borrowed $7,214 more than their white peers, while Latinx students borrowed $453 more.

The state of Texas has emphasized that debt-to-income ratios at certain institutions will not be held to the 60 percent threshold. However, conversations have begun that explore attaching sanctions to individual institution's debt-to-income ratio.

The study highlights that this could be concerning as the public universities that were shown to have the highest median debt burdens in Texas were Prairie View A&M University, Texas Southern University, Stephen F. Austin State University, Texas A&M University - Commerce and the University of North Texas at Dallas. Many of these colleges also have higher-than-average rates of Latinx and black student enrollment, Baker noted.

"So it would be inequitable to sanction institutions solely for serving certain student populations," Baker said.

The study was based on data from the Texas Higher Education Coordinating Board and the Texas Workforce Commission. Baker merged information from both sources to determine students' debt-to-income ratios.

Only four-year college students who graduated with a bachelor's degree and worked full-time in the year immediately following graduation in Texas were included. The 40,000 students who were part of the study started undergraduate college between 2004 and 2008.

Baker said that the Texas goal of keeping the debt-to-income ratio at 60 percent or less for undergraduates is admirable. But she warned that any state looking to adopt such a model should be cautious about penalizing public universities that routinely fail to meet that target for its students because those colleges have more racial minorities, like a historically-black college.

"Future research needs to be conducted on incorporating measures of affordability in state accountability structures in ways that do not penalize underserved student populations," she said.

Student debt has become a key issue in the 2020 presidential campaign, as college tuition continues to rise and borrowers nationwide owe a total of $1.5 trillion in federal student loan debt. Concern over students' ability to repay undergraduate debt led to the creation of goal 4 of the 60x30TX strategic plan, which was developed by the Texas Higher Education Coordinating Board.

CHAMPAIGN, Ill. -- University of Illinois electrical engineers have cleared another hurdle in high-power semiconductor fabrication by adding the field's hottest material - beta-gallium oxide - to their arsenal. Beta-gallium oxide is readily available and promises to convert power faster and more efficiently than today's leading semiconductor materials - gallium nitride and silicon, the researchers said.

Their findings are published in the journal ACS Nano.

Flat transistors have become about as small as is physically possible, but researchers addressed this problem by going vertical. With a technique called metal-assisted chemical etching - or MacEtch - U. of I. engineers used a chemical solution to etch semiconductor into 3D fin structures. The fins increase the surface area on a chip, allowing for more transistors or current, and can therefore handle more power while keeping the chip's footprint the same size.

Developed at the U. of I., the MacEtch method is superior to traditional "dry" etching techniques because it is far less damaging to delicate semiconductor surfaces, such as beta-gallium oxide, researchers said.

"Gallium oxide has a wider energy gap in which electrons can move freely," said the study's lead author Xiuling Li, a professor of electrical and computer engineering. "This energy gap needs to be large for electronics with higher voltages and even low-voltage ones with fast switching frequencies, so we are very interested in this type of material for use in modern devices. However, it has a more complex crystal structure than pure silicon, making it difficult to control during the etching process."

Applying MacEtch to gallium oxide crystals could benefit the semiconductor industry, Li said, but the advancement is not without hurdles.

"Right now, the etching process is very slow," she said. "Because of the slow rate and the complex crystal structure of the material, the 3D fins produced are not perfectly vertical, and vertical fins are ideal for efficient use of power."

In the new study, the beta-gallium oxide substrate produced triangular, trapezoidal and tapered fins, depending on the orientation of metal catalyst layout relative to the crystals. Although these shapes are not ideal, the researchers were surprised to find that they still do a better job conducting current than the flat, unetched beta-gallium oxide surfaces.

"We are not sure why this is the case, but we are starting to get some clues by performing atomic-level characterizations of the material," Li said. "The bottom line is that we have shown it is possible to use the MacEtch process to fabricate beta-gallium oxide, a potentially low-cost alternative to gallium nitride, with good interface quality."

Li said further research will need to address the slow etch rate, enable high performance beta-gallium oxide devices, and try to get around the problem of low thermal conductivity.

"Increasing the etch rate should improve the process's ability to form more vertical fins," she said. "This is because the process will happen so quickly that it will not have time to react to all of the differences in crystal orientations."

The low thermal conductivity issue is a deeper problem, she said. "High-power electronics produce a lot of heat, and device researchers are actively seeking thermal engineering solutions. While this is a wide-open aspect in the semiconductor field right now, 3D structures like what we have demonstrated could help guide the heat out better in some device types."