Culture

Researchers from Stellenbosch University, South Africa found that tortoises, one of the main herbivores of the daisies, were unable to distinguish the lower petal surfaces against a green leaf background. Tortoises prefer to eat protein-rich flowers over leaves, but when confronted with closed flowers, they showed no preference between them.

When the researchers modelled the colours of the lower petal surfaces in the vision of other herbivores, they also found these colours to be indistinguishable from leaves.

In contrast, species of daisy that do not close at night produced the same colouration on their lower petals as the upper petals exposed to pollinators.

Plants face an evolutionary conflict between having flowers that attract pollinators while avoiding herbivores. Often plants defend themselves chemically, but this can have adverse effects on pollination.

"When plants defend their flowers chemically, the pollination interactions can be negatively influenced. Our study shows a novel way in which flowers can avoid herbivores, without compromising pollination interactions." Says Dr. Jurene Kemp, lead author of the study.

"These flowers can potentially circumvent the conflict of attracting both pollinators and herbivores by producing attractive colours on the surfaces that are exposed to pollinators (when flowers are open) and cryptic colours that are exposed when herbivores are active (when flowers are closed)."

In Namaqualand, South Africa, where the research took place, daises bloom annually in a spring flowering. This makes preserving flowers, responsible for reproduction, particularly important.

The researchers examined the colouration of 77 Asteraceae species, modelling how they appear in the visual systems of chameleons, horses and goats as proxies for tortoises and larger herbivores in the area, like springbok. They then tested the preferences of real tortoises with both open and closed flowers against leaf backgrounds.

Not all Asteraceae species that close their flowers had cryptically coloured lower petal surfaces, but in the experiments, the tortoises did not readily eat these flowers. Dr. Kemp said, "One interesting question would be to test whether non-cryptic flowers have chemical defences, and whether these chemical defences are absent in the cryptic flowers."

On further research Dr. Kemp said "Unfortunately, we could only do this using one plant family in one botanical region, it would be great to see if other plant species also use colour to avoid herbivores."

The researchers would also have liked to use larger herbivores such as springboks in their behavioural experiments, but Dr. Kemp adds that "this was practically not possible."

Longer NFL careers and certain playing positions appear to each spell greater long-term risk for serious cognitive problems such as confusion, memory deficits, depression and anxiety in former football players, according to a new report published Aug. 30 in The American Journal of Sports Medicine.

The study is believed to be the first to explore the interplay between career length, position and cognitive and mental health outcomes among professional football players.

The analysis--based on a survey of nearly 3,500 former NFL players--was conducted by investigators at the Harvard T.H. Chan School of Public Health and Harvard Medical School as part of the ongoing Football Players Health Study at Harvard University.

The study results show that players who experienced concussions had elevated risk for serious cognitive problems, depression and anxiety, which persisted over time, as long as 20 years following injury. The investigators caution that their analysis relied on players' memories of experiencing concussion rather than on diagnosis at the time of injury. And the findings do not mean that everyone with concussion will necessarily experience cognitive or mental health problems, they add. Contrary to previous reports, the new research did not find a link between starting football at a young age and cognitive problems in adulthood.

On one level, the researchers say, many of their findings make intuitive sense and confirm what some might have already suspected: The longer players remain in the game, the more likely they are to suffer a head injury, which increases the risk for neurocognitive problems. It also affirms that certain positions are more prone to concussions and, therefore, players in them face greater risk for experiencing the downstream of effects of head injury.

Nonetheless, the researchers said, the analysis is the first to document and quantify the risk that stems from lengthier careers and certain high-impact positions.

Specifically, the analysis showed that players who reported the most concussion symptoms had 22-fold risk of reporting serious long-term cognitive problems and six times the risk of having symptoms of depression and anxiety, compared with those who reported the fewest symptoms.

"Our findings confirm what some have suspected--a consistently and persistently elevated risk for men who play longer and who play in certain positions," said study lead investigator Andrea Roberts, a research scientist at the Harvard T.H. Chan School of Public Health. "Our results underscore the importance of preventing concussions, vigilant monitoring of those who suffer them and finding new ways to mitigate the damage from head injury."

For the study, former players, average age 53, were asked about the number of seasons played in the NFL, their positions and any history of blows to the head or neck followed by symptoms of concussion such as dizziness, confusion, vision problems, loss of consciousness, nausea, headaches and seizures, among other symptoms. Based on the number and severity of symptoms, players were given a concussion score.

Overall, one in eight players (12 percent) reported signs of serious cognitive problems. By comparison, about 2 percent of people in the general population in the United States report such problems. Age made no difference in the interplay between concussion and cognitive problems, the study showed. Those under age 52 reported serious cognitive problems at a similar rate as the rest (13 percent), a finding that suggests neurocognitive decline was likely not a function of mere aging. Alarmingly, that risk remained magnified even in those 45 and younger. Indeed, 30 percent of players 45 and younger who had the most concussions reported serious cognitive problems.

To gauge whether the number of seasons played and position type were linked to depression, anxiety and cognitive problems, the researchers used standard questionnaires commonly used to screen for the presence of such disorders. The researchers compared the proportion of players with serious cognitive problems among individuals with various career lengths--one season, two to four seasons, five to six seasons, seven to nine seasons and 10 seasons or more. Overall, those with the longest careers--10 seasons or more--were twice as likely to report severe cognitive problems compared with players who'd played a single season--12.6 percent in the 10-plus season group reported signs of severe cognitive problems, compared with 5.8 percent in the single-season category. The risk crept up proportionally with the number of seasons played, growing progressively higher as the number of years increased. Every five seasons of play carried a nearly 20 percent increase in risk for serious cognitive problems.

Which position one played also mattered. To evaluate the risk-position link, the researchers divided players into three groups based on the average concussion symptoms per year that players reported in each position. Kickers, punters and quarterbacks had the fewest symptoms per year, followed by wide receivers, defensive backs, linemen and tight ends. The groups with the highest number of symptoms included running backs, linebackers and special teams.

Those in the group with the most concussion symptoms had twice the risk for serious cognitive problems--15 percent of those in this group had cognitive difficulties--compared with those reporting the fewest concussion symptoms (6 percent). Those with the most concussions also had a nearly 50 percent greater risk for depression and anxiety, compared with those playing in the group with the fewest concussion symptoms. One in four in the first group had symptoms indicative of depression, compared with 15 percent of players reporting problems in the latter one, while 27 percent had signs of anxiety, compared with 16 percent in the group with the fewest concussions. Those who played in the mid-range group had a 75 percent higher risk of cognitive problems and a 40 percent elevation in risk for depression and anxiety, compared with players in the group with the fewest symptoms.

Nearly one in four players reported symptoms of anxiety (26 percent) and depression (24 percent), and nearly one in five (18 percent) reported symptoms of both conditions. Career length influenced risk for depression, with every five seasons boosting the risk by 9 percent. The number of seasons, however, was not linked to greater anxiety risk.

The age at which an individual started playing organized football did not affect risk. Indeed, outcomes were similar between those who began playing the game before age 12 and those who began later. The findings, however, pertain solely to former NFL players and not necessarily to the general population, the researchers caution. The question of when a child should start playing organized football remains very much open, and should be made by each individual family, the researchers said.

"The overarching goal of the Football Players Health Study is to unravel risk factors and disease mechanisms and to inform interventions that preserve and optimize player health and wellness," said study senior author Marc Weisskopf, the Cecil K. and Philip Drinker Professor of Environmental Epidemiology and Physiology at the Harvard T.H. Chan School of Public Health. "These latest findings confirm much of what we know but they add much needed granularity and specificity to risk magnitude by career length and position."

"Clearly, not everyone who sustains a concussion is destined for cognitive trouble, but the results of the research highlight just how critical it is to continue to find ways to prevent head injuries from occurring in the first place because of the many downstream and long-lasting effects on physical, cognitive and mental health," said Ross Zafonte, the Earle P. and Ida S. Charlton Professor of Physical Medicine and Rehabilitation and head of the Department of Physical Medicine and Rehabilitation at Harvard Medical School. Zafonte is also principal investigator of the Football Players Health Study.

Humans had caused significant landcover change on Earth up to 4000 years earlier than previously thought, University of Queensland researchers have found.

The School of Social Sciences' Dr Andrea Kay said some scientists defined the Anthropocene as starting in the 20th century, but the new research showed human-induced landcover change was globally extensive by 2000BC.

The Anthropocene - the current geological age - is viewed as the period in which human activity has been the dominant influence on Earth's climate and the environment.

"The activities of farmers, pastoralists and hunter-gatherers had significantly changed the planet four milennia ago,'' Dr Kay said.

The ArchaeoGLOBE project used an online survey to gather land-use estimates over the past 10,000 years from archaeologists with regional expertise.

"The modern rate and scale of anthropogenic global change is far greater than those of the deep past, but the long-term cumulative changes that early food producers wrought on Earth are greater than many people realise," Dr Kay said.

"Even small-scale, shifting agriculture can cause significant change when considered at large scales and over long time-periods."

Fellow researcher Dr Nicole Boivin said the innovative crowdsourcing-from-experts approach to pooling archaeological data had provided the project with a unique perspective.

"Archaeologists possess critical datasets for assessing long-term human impacts to the natural world, but these remain largely untapped in terms of global-scale assessments," Dr Boivin said.

Another researcher on the team, Dr Alison Crowther, said the study could help plan for future climate scenarios.

"This research and the collaborative approach we used means we can better understand early land use as a driver of long-term global environmental changes across the Earth's system," Dr Crowther said.

Many anesthesiologists forbid patients from chewing gum in the immediate hours before surgery for fear that it would increase the risk that the patient's stomach contents might end up dumped (aspirated) into the patient's lungs, with potentially deadly consequences (aspiration pneumonitis). However, current data now suggest that the preoperative use of chewing gum does not adversely affect gastric emptying and that the postoperative use of chewing gum may actually aid recovery in some forms of major surgery. The Open Anesthesia Journal is pleased to announce the publication of a clinical review on this important topic. Entitled "Chewing Gum Use in the Perioperative Period " and authored by Dr. D. John Doyle from the Department of General Anesthesiology at Cleveland Clinic Abu Dhabi, this open-access peer-reviewed article will be valuable for hospitals and clinics interested in updating their perioperative policies.

A unique Victorian databank that profiles children with hearing loss will help researchers globally understand why some children adapt and thrive, while others struggle.

The Victorian Childhood Hearing Impairment Longitudinal Databank, which has collected information for eight years, is featured in the latest International Journal of Epidemiology.

Its data shows that language development and speech in hearing-impaired children lags behind other children, despite advancements in earlier detection and intervention in the past decade.

The paper's* lead author, Murdoch Children's Research Institute's (MCRI) Dr Valerie Sung, says researchers world-wide can use the databank to answer questions around childhood hearing loss.

"This register can help us understand why some children with a hearing loss do so well, while others experience greater difficulties," she says.

"Universal newborn hearing screening is detecting hearing loss earlier than ever before, usually within a few weeks of birth.

"Children with hearing loss have very early access to hearing aids, early intervention services and for some, cochlear implantation. It was expected that hearing-impaired children would quickly come to enjoy the same language and educational outcomes as their hearing peers.

"However, early clinical diagnosis and intervention does not guarantee equality in health outcomes, with language and related outcomes of children with hearing loss remaining on average well below population means and the children's true cognitive potential.

"Demonstrating the reasons for this inequality has been hampered until now by the lack of population based prospective research."

The Victorian Childhood Hearing Impairment Longitudinal Databank (VicCHILD) is a population-based longitudinal databank open to every child with permanent hearing loss in Victoria.

VicCHILD started in 2012 and stems from 25 years of work by The Royal Children's Hospital and MCRI. At the end 2018, 807 children were enrolled and provided baseline data. By 2020 more than 1000 children will be taking part, making it the largest hearing databank in the world.

VicCHILD collects data at enrolment, two years of age, school entry and late primary /early high school. It involves parent questionnaires, child assessments and taking saliva samples.

Dr Sung, who is also a honorary fellow at the University of Melbourne, says about 600 Australian infants each year are diagnosed with congenital hearing loss within weeks of birth.

"As these children grow, they can face challenges in things that come naturally to others like language and learning. This can impact their quality of life," she says.

"Hearing loss incurs significant burden and medical costs and impacts adversely on educational attainment and employment opportunities.

"This important bank of information could improve interventions and ultimately the lives of children with hearing loss and their families. It will also act as a platform for research trials to understand the effectiveness of different interventions."

Our teeth take thousands of bites per day, and understanding exactly what holds them in place and how is key to helping people live with their own teeth for longer.

Now new research published in the Journal of Dental Research has shed light on the science behind the formation of the periodontal ligament, which helps keep the tooth stable in the jawbone. This improved understanding will also help scientists work towards regenerating the tissues that support teeth.

The study, led by the Universities of Plymouth and Geneva, shows how a *signalling pathway called Notch, which is known to be activated in stem cells and cancer, is important for periodontal ligament development.

*A signalling pathway describes how a group of molecules in a cell work together to control one or more cell functions, such as cell division or cell death. After the first molecule in a pathway receives a signal, it activates another molecule. This process is repeated until the last molecule is activated and the cell function is carried out.

Abnormal activation or inhibition of certain signalling pathways can lead to cancer and other conditions, including problems with tissue regeneration.

A key finding in the new study, which was conducted in rodent teeth, is that Lamin A, a cell nuclear protein, is a direct target of Notch pathway.

Lamin A is best known for its mutated form progerin, which causes fatal 'early ageing' disease, Progeria syndrome - but by uncovering its involvement in periodontal ligament formation, scientists have better insight into how molecules function during tissue regeneration, and how the process could be affected during disease.

Corresponding author Dr Bing Hu, Associate Professor of Oral and Dental Health Research in Peninsula Dental School at the University of Plymouth, said: "The periodontal ligament starts to properly hold the tooth in the jawbone when a tooth breaks out and becomes functional.

"Understanding the mechanisms of how periodontal ligaments develop and the molecules that assist the tissue becoming mature is really important for our understanding of tissue regeneration and repair.

"The next steps are for us to see if and how the molecules we have identified in this study can be translated into a human-only model and, in turn, how they are affected in both healthy and diseased conditions."

Dr Hu is also part of the University's Institute of Translational and Stratified Medicine (ITSMed).

This research is a part of the MD-PhD thesis of Dr Balázs Dénes of the University of Geneva, entitled Post-emergent tooth eruption: eruption rate, periodontal ligament maturation and cell signalling, directed by Professor Stavros Kiliaridis.

Dr Dénes said: "We believe that our findings are an important stepping stone to better dental treatments in situations involving the periodontal ligament, such as gum disease (periodontitis), tooth restoration by dental implants or orthodontic tooth movement."

Researchers from Sweden, Germany, Brazil and the USA have developed a financial mechanism to support the protection of the world's natural heritage. In a recent study, they developed three different design options for an intergovernmental biodiversity financing mechanism. Asking what would happen if money was given to countries for providing protected areas, they simulated where the money would flow, what type of incentives this would create - and how these incentives would align with international conservation goals.

After long negotiations, the international community has agreed to safeguard the global ecosystems and improve on the status of biodiversity. The global conservation goals for 2020, called the Aichi targets, are an ambitious hallmark. Yet, effective implementation is largely lacking. Biodiversity is still dwindling at rates only comparable to the last planetary mass extinction. Additional effort is required to reach the Aichi targets and even more so to halt biodiversity loss.

"Human well-being depends on ecological life support. Yet, we are constantly losing biodiversity and therefore the resilience of ecosystems. At the international level, there are political goals, but the implementation of conservation policies is a national task. There is no global financial mechanism that can help nations to reach their biodiversity targets", says lead author Nils Droste from Lund University, Sweden.

Brazil has successfully implemented Ecological Fiscal Transfer systems that compensate municipalities for hosting protected areas at a local level since the early 1990's. According to previous findings, such mechanisms help to create additional protected areas. The international research team has therefore set out to scale this idea up to the global level where not municipalities but nations are in charge of designating protected areas. They developed and compared three different design options:

An ecocentric model: where only protected area extent per country counts - the bigger the protected area, the better;

A socio-ecological model: where protected areas and Human Development Index count, adding development justice to the previous model;

An anthropocentric model: where population density is also considered, as people benefit locally from protected areas.

The socio-ecological design was the one that proved to be the most efficient. The model provided the highest marginal incentives - that is, the most additional money for protecting an additional percent of a country's area - for countries that are the farthest from reaching the global conservation goals. The result surprised the researchers.

"While we developed the socio-ecological design with a fairness element in mind, believing that developing countries might be more easily convinced by a design that benefits them, we were surprised how well this particular design aligns with the global policy goals", says Nils Droste.

"It would most strongly incentivize additional conservation action where the global community is lacking it the most", he adds.

As the study was aimed at providing options, not prescriptions for policy makers, the study did not detail who should be paying or how large the fund should exactly be. Rather, it provides a yet unexplored option to develop a financial mechanism for biodiversity conservation akin to what the Green Climate Fund is for climate change.

"We know that we need to change land use in order to preserve biodiversity. Protecting land from degradation and providing healthy ecosystems, clean air or clean rivers is a function of the state. Giving a financial reward to governments for such public ecosystem services will ease the provision of corresponding conservation efforts and will help to put this on the agenda", concludes Nils Droste.

The momentum behind a move to plant-based and vegan diets for the good of the planet is commendable, but risks worsening an already low intake of an essential nutrient involved in brain health, warns a nutritionist in the online journal BMJ Nutrition, Prevention & Health.

To make matters worse, the UK government has failed to recommend or monitor dietary levels of this nutrient--choline--found predominantly in animal foods, says Dr Emma Derbyshire, of Nutritional Insight, a consultancy specialising in nutrition and biomedical science.

Choline is an essential dietary nutrient, but the amount produced by the liver is not enough to meet the requirements of the human body.

Choline is critical to brain health, particularly during fetal development. It also influences liver function, with shortfalls linked to irregularities in blood fat metabolism as well as excess free radical cellular damage, writes Dr Derbyshire.

The primary sources of dietary choline are found in beef, eggs, dairy products, fish, and chicken, with much lower levels found in nuts, beans, and cruciferous vegetables, such as broccoli.

In 1998, recognising the importance of choline, the US Institute of Medicine recommended minimum daily intakes. These range from 425 mg/day for women to 550 mg/day for men, and 450 mg/day and 550 mg/day for pregnant and breastfeeding women, respectively, because of the critical role the nutrient has in fetal development.

In 2016, the European Food Safety Authority published similar daily requirements. Yet national dietary surveys in North America, Australia, and Europe show that habitual choline intake, on average, falls short of these recommendations.

"This is....concerning given that current trends appear to be towards meat reduction and plant-based diets," says Dr Derbyshire.

She commends the first report (EAT-Lancet) to compile a healthy food plan based on promoting environmental sustainability, but suggests that the restricted intakes of whole milk, eggs and animal protein it recommends could affect choline intake.

And she is at a loss to understand why choline does not feature in UK dietary guidance or national population monitoring data.

"Given the important physiological roles of choline and authorisation of certain health claims, it is questionable why choline has been overlooked for so long in the UK," she writes. "Choline is presently excluded from UK food composition databases, major dietary surveys, and dietary guidelines," she adds.

It may be time for the UK government's independent Scientific Advisory Committee on Nutrition to reverse this, she suggests, particularly given the mounting evidence on the importance of choline to human health and growing concerns about the sustainability of the planet's food production.

"More needs to be done to educate healthcare professionals and consumers about the importance of a choline-rich diet, and how to achieve this," she writes.

"If choline is not obtained in the levels needed from dietary sources per se then supplementation strategies will be required, especially in relation to key stages of the life cycle, such as pregnancy, when choline intakes are critical to infant development," she concludes.

Exercise immediately prior to and during pregnancy restores key tissues in the body, making them better able to manage blood sugar levels and lowering the risk of long term health problems, suggests new research carried out in mice.

Researchers at the University of Cambridge, who led the study published today in the journal Physiological Reports, say the findings reinforce the importance of an active lifestyle when planning pregnancy.

In the UK, more than a half of all women of reproductive age and almost a third of pregnant women are overweight or obese. This is particularly concerning, as being overweight or obese during pregnancy increases the risk of complications in the mother, such as gestational diabetes, and predisposes both her and her infant to develop metabolic diseases such as type 2 diabetes in the years after pregnancy.

Exercise is known to improve how the body manages blood sugar levels and thereby reduce the risk of type-2 diabetes and metabolic syndrome in non-pregnant women. It also has positive effects prior to and during pregnancy, with beneficial outcomes for both mother and her child, preventing excessive gestational weight gain and the development of gestational diabetes, and the need for insulin use in women who have already developed gestational diabetes. However, little is known about the changes that exercise causes to the tissues of obese pregnant mother.

To answer this questions, researchers at the University of Cambridge fed mice a sugary, high fat diet such that they become obese and then the obese mice were exercised. The mice exercised on a treadmill for 20 minutes a day for at least a week before their pregnancy and then for 12.5 minutes a day until day 17 of the pregnancy (pregnancy lasts for around 20 days in mice).

Mice are a useful model for studying human disease as their biology and physiology have a number of important characteristics in common with those of humans, including showing metabolic changes with obesity/obesity-causing diets and in the female body during pregnancy.

The researchers found that the beneficial effects on metabolic health in obese mothers related to changes in how molecules and cells communicate in maternal tissues during pregnancy.

"A moderate level of exercise immediately before and then during pregnancy leads to important changes in different tissues of the obese mother, effectively making the tissues more like those seen in non-obese mothers," says Dr Amanda Sferruzzi-Perri, a Royal Society Dorothy Hodgkin Research Fellow from the Centre for Trophoblast Research in the Department of Physiology, Development and Neuroscience at the University of Cambridge, who co-led the study.

"We believe these changes may explain how exercise improves the metabolism of the obese mother during pregnancy and, in turn, may prevent her babies from developing early signs of type 2 diabetes after birth."

The key organs of the mother that were affected by exercise were:

white adipose tissue - the fatty tissue that stores lipids and can be found in different parts around the body, including beneath the skin and around internal organs;

skeletal muscle - muscle tissue that uses glucose and fats for contraction and movement;

the liver - the organ that stores, as well as syntheses lipids and glucose.

Exercise affected key signalling pathways - the ways that molecules and cells within tissue communicate - involved in responding to insulin (the hormone that stimulates glucose uptake by white adipose tissue and skeletal muscle), in storage and breakdown of lipids (fats found in the blood and tissue) and in growth and the synthesis of proteins.

White adipose tissue showed the greatest number of changes in response to exercise in the obese pregnant mouse, being restored to a state similar to that seen in the tissue of non-obese mothers. This suggests that insulin resistance of the mother's white adipose tissue may be the cause of poor glucose-insulin handling in obese pregnancies. The findings are different to that seen in non-pregnant animals, whereby exercise typically affects insulin signalling in the skeletal muscle.

In addition, the team's previous work showed that exercise improves sensitivity to insulin and glucose handling throughout the whole body in the obese mother. It also prevents the development of insulin resistance in the offspring of obese mothers after birth. Low insulin sensitivity/insulin resistance requires larger amounts of insulin to control blood glucose levels.

"Our findings reinforce the importance of having an active lifestyle and eating a healthy balanced diet when planning pregnancy and throughout for both the mother and her developing child," says co-lead Professor Susan Ozanne from the Wellcome Trust-Medical Research Council Institute of Metabolic Science at the University of Cambridge.

"This is can be important in helping to reduce the risk of adverse health problems in the mother and of later health problems for her child."

Tiny changes in the microscopic structure of the human brain may affect how patients respond to an emerging therapy for neurological problems.

The technique, called non-invasive electrical brain stimulation, involves applying an electrical current to the surface of a patient's head to stimulate brain cells, altering the patient's brain activity. It is being trialled for a range of neurological problems including recovery from stroke, traumatic brain injury, dementia, and depression, but research to date has found the effects to be inconsistent

Now, a team led by researchers at Imperial College London has shed more light on why these inconsistencies occur and may provide physical evidence for why some patients respond better than others - because of the fine structure of their brain tissue. The new research suggests it may be possible to target the therapy to those patients most likely to benefit.

They found that differences in the makeup of the brain's white matter - the tissue deep in the brain and rich in the branching 'tails' of nerve cells - were key. The research revealed that those who had more connectivity in the regions being stimulated were more likely to respond better to the treatment.

According to the team, the findings, published in the journal Brain, could help to personalise the non-invasive electrical brain stimulation, targeting the treatment to patients who are most likely to gain clinical benefits.

Dr Lucia Li, a clinical lecturer in neurology in the Department of Brain Sciences at Imperial College London, and lead author of the study, said: "With all the current buzz around brain stimulation for altering brain activity, it's important to understand who will benefit most from this technique in the clinic.

"Problems with white matter structure are a feature of a range of different neurological conditions. Our study is a step towards more personalised use of brain stimulation, which will improve the outcomes using this technique, as well as reduce the number of people treated un-necessarily."

In the study, researchers looked at 24 healthy patients and 35 patients recovering from a moderate or severe traumatic brain injury (TBI). Participants performed a task inside an MRI scanner (see 'The Stop Signal Task' in notes to editors) while receiving small amounts of electrical current through electrodes on the surface of the scalp or a placebo. They were unable to tell whether they were receiving brain stimulation or not.

They found that healthy participants who received brain stimulation performed better in the task than when they didn't receive the treatment. For patient with TBI, task performance in response to stimulation varied widely.

However, when they analysed MRI scans, they found that those participants with highly-connected white matter in the brain region being stimulated responded best to the treatment, and those who had damaged or less-connected regions of white matter showed less improvement.

They also found that brain stimulation could partially reverse some of the abnormalities in brain activity caused by TBI.

The team cautions that while more work is needed to confirm the findings, it could mean brain stimulation might prove a useful treatment approach for other neurological conditions with abnormal brain activity as a feature, such as dementia.

"We found that people with stronger white matter connections in their brain had better improvement with stimulation," Dr Li explained. "This might be an important reason why previous studies have found that some people benefit from stimulation, whilst others don't and means we can start using brain stimulation in a more personalised way."

According to the researchers, the study is limited in that in that they only investigated one type of cognitive behaviour and would need to be replicated in other types of behaviour to show if the findings apply more generally. In addition, they only stimulated one region of the brain, so they don't know whether the effects are specific to this region, or whether other regions can be stimulated.

Dr Li explains the team will now focus on larger studies with more participants to investigate what other factors influence someone's response to brain stimulation. They will also apply the technique to other conditions with abnormalities in brain activity to see if they can alter activity and improve brain function.

Since chikungunya virus emerged in the Americas in 2013, it has infected millions of people, causing fever, headache, rash, and muscle and joint pain. For some people, painful, debilitating arthritis lasts long after the other symptoms have resolved. Researchers have suspected that the virus or its genetic material - in this case, RNA - persist in the body undetected, but they have been unable to find its hiding places.

Now, researchers at Washington University School of Medicine in St. Louis have figured out a way to detect cells infected with chikungunya virus that survive the infection. They genetically modified the virus such that it activated a fluorescent tag within cells during infection. Months after the initial infection, the researchers could detect glowing red cells still harboring viral RNA.

The study, in mice, opens up new ways to understand the cause of - and find therapies for - chronic viral arthritis.

The findings are published Aug. 29 in PLOS Pathogens.

Senior author Deborah Lenschow, MD, PhD, an associate professor of medicine and of pathology and immunology, and co-first author and graduate student Marissa Locke answered questions about the research, which was conducted in collaboration with co-first author Alissa Young, PhD, co-author Michael S. Diamond, MD, PhD, the Herbert S. Gasser Professor of Medicine, and others.

How common is chronic arthritis caused by chikungunya infection?

Lenschow: Between 30% and 60% of people infected with chikungunya virus go on to develop chronic arthritis that can last up to three or four years after infection. Researchers had found viral RNA in joint fluid from people with chronic arthritis, but they didn't know whether the virus had gone dormant or whether it was still multiplying and infecting new cells at an undetectably low level.

Locke: Nobody had located the cells that harbored the viral RNA. This matters because if we can't find the infected cells, we can't study them.

Where did you find the virus, and what does that tell you about the cause of chronic arthritis?

Locke: We found the virus in muscle cells and in connective tissue cells in the skin and muscle. These cells likely had become infected within the first week of the virus invading the body, yet managed to survive. They were still there in the muscles and joints up to 114 days after infection, and they still had viral RNA inside them.

Lenschow: One hypothesis would be that the viral RNA that's persisting in the cells is triggering chronic inflammation, and that is what contributes to the symptoms of arthritis. For reasons that we don't understand, inflammation fails to get rid of the viral RNA, or at least not quickly.

What impact will the development of this new tagging technique have on people suffering from chronic viral arthritis?

Lenschow: We're a long way from having a treatment to offer people. But the first step to developing a therapy is understanding the cause of the symptoms, and this technique helps us accomplish that. If we understand the cause, that could hopefully lead us to identify therapeutic interventions to help alleviate some of the chronic symptoms.

Locke: We can use this approach to find out what's driving the chronic inflammation and how to resolve it. We can study which proteins or other components of the immune response worsen or alleviate the inflammation, and what happens to the infected cells when we turn those components up or down.

A significant proportion of eScooter injuries in the US seem to be occurring while 'drivers' are under the influence of drugs and/or alcohol and almost never wearing a helmet, suggests a study of admissions to three US major trauma centres, published online in Trauma Surgery & Acute Care Open.

Most of those injured are men aged 20 to 40, the findings indicate.

Motorised stand up or kick scooters date back to 1915. But electronic or eScooters have only recently gained mass appeal and come into widespread use since 2017.

Promoted as a cheap, eco friendly means of transport, eScooters combine the size of a child's push scooter with the speed and power of an electronic bicycle.

Although partially or completely banned in some US cities, they are nevertheless widely available to rent all over the US, and in many other regions of the world, including Europe.

They are currently banned from use on public roads in the UK, but the Department of Transport is currently reviewing the law.*

Given their soaring popularity in the US, the researchers wanted to look at the patterns of injury associated with their use, and other potentially influential factors, such as the wearing of helmets and drug and alcohol use.

They drew on the numbers of patients admitted to three Level 1 (major) trauma centres between September 2017 and October 2018.

During this period, 103 people were admitted with eScooter injuries, with monthly admissions rising sharply from August 2018 onwards, to reach 43 by October 2018 alone.

The average age of the injured was 37, with more than six out of 10 (62%) in the 20 to 40 age bracket.Two thirds of the patients were men.

More than four out of 10 (42%) were moderately to severely injured, as measured by the Median Injury Severity Score. One person was critically injured.

The bulk of the injuries (42%) involved fractures to the leg bones (tibia and fibula); the bony protrusions at the ankle (malleoli); the collar bone (clavicle); shoulder blades (scapula); and the forearm bone (ulna). Half the patients (53%) with these injuries required surgery.

Facial fractures were the next most common type of injury: 27 (26%) patients had these, most of which were mild, but required surgery in six (22%) cases.

Nearly one in five (18%) patients had a bleed on the brain, although none required surgery, and a further 17 people were concussed.

Five other serious injuries included haemothorax (blood in the space between the lungs and the chest wall); tears in the spleen; kidney injury; and neck injury (cervical spine).

In all, one in three people required surgery. And while most (86%) were discharged home, six patients required long term nursing care/rehabilitation, and two needed care at home.

Information on helmet use was missing for five patients, but of the remainder, virtually none was wearing one at the time of the incident (98%).

Drug and alcohol use was common. Most patients (79%) were tested for alcohol, and around half (48%) were well above the legal limit. Sixty per cent were also screened for drugs, and half (52%) tested positive.

The most common substances found were tetrahydrocannabinol (THC), one of the active ingredients in cannabis (32%), followed by methamphetamine and amphetamines (18%).

The researchers suggest that eScooters may be particularly attractive to risk takers. "Studies in China have found that eScooter riders are also more likely to exhibit risky driving such as riding in traffic lanes and driving against traffic compared with bicycle and electronic bicycle riders.

"Our current study also supports this hypothesis, consisting primarily of men aged 20 to 40 years with a high rate of alcohol use, drug use, and lack of helmet use," they write.

This is an observational study, and as such, can't establish cause. The total number of patients was small and the researchers weren't able to glean information on the frequency, locations, or patterns of eScooter use.

What's more, the research focused on patients admitted to major trauma centres, and there may be a large number of people who sustain more minor injuries after riding an eScooter.

But they conclude: "As the popularity of alternate modes of transportation continues to rise, eScooter related injuries are likely to increase as well."

A mutation that causes a type of muscular dystrophy that affects the limbs protects against HIV-1 infection, according to a study published August 29 in the open-access journal PLOS Pathogens by Sara Rodríguez-Mora, Mayte Coiras and José Alcamí of the Instituto de Salud Carlos III in Madrid, Spain, and colleagues. As the authors noted, this is the second reported genetic defect known to induce strong resistance against HIV-1 infection in humans.

The Transportin 3 gene (TNPO3) encodes a protein, TNP03, that has been described as a key factor in HIV-1 infection. In 2001, researchers discovered a relationship between a genetic defect in TNPO3 and limb girdle muscular dystrophy 1F (LGMD1F) -- a rare muscle disease that causes weakness in the limbs and pelvis. In LGMD1F patients, TNPO3 generates a mutated protein called TNPO3_mut.

In the new study, Rodríguez-Mora Coiras and Alcamí analyzed the effect of TNPO3_mut on HIV-1 infection using blood cells from patients with LGMD1F. The results show that cells from patients with this mutation in TNPO3 are resistant to HIV-1 infection. According to the authors, cells from LGMD1F patients can be used to understand the mechanisms of action of TNPO3 in HIV infection and to design new therapeutic strategies for the treatment of both diseases.

Humans' ability to transform the natural environment is often considered a modern phenomenon, from increasing deforestation, soil erosion and greenhouse gas emissions. This year, an international group of geologists deemed the start of the Anthropocene -- the time of humans' most far-reaching effects on the Earth -- to be the middle of the 20th century.

But what constitutes transformation, or even significant human activity, is still debated, and many researchers challenge the relatively recent frame placed around history.

A new map synthesized from more than 250 archaeologists worldwide argues that the human imprint on our planet's soil goes back much earlier than the nuclear age. A core group of those researchers, including the University of Washington, the University of Maryland Baltimore County and the Max Planck Institute for the Science of Human History, illustrate in an Aug. 30 study in Science how foragers and, eventually, farmers fundamentally altered the land on the planet by 3,000 years ago.

The ArchaeoGLOBE project analyzes land use from roughly 10,000 years ago, the time of hunters and gatherers, to the year 1850, after the Industrial Revolution. The new study adds an archaeological perspective to existing models of historical land use. Based on researchers' expertise of land use on six continents, the crowdsourced map shows that agriculture -- an extraction of environmental resources that leaves a complex mark on the landscape -- began earlier, and in more parts of the world, than more recent studies have reported.

"There are archaeologists working all over the world, but they aggregate data differently, and it can be difficult to find larger patterns," said co-author Ben Marwick, an associate professor of anthropology at the UW. "By asking archaeologists a series of questions rather than combining datasets, we've created a brilliant workaround -- essentially, what were people doing, and how much, in different parts of the world?"

Commonly cited recent studies have used statistics and maps to estimate human behavior and environmental change prior to modern times. For the ArchaeoGLOBE project, the research team spent months developing the survey and considering how to divide up the Earth into analytical regions, said Lucas Stephens, who led the global collaboration of archaeologists while a doctoral student at the University of Pennsylvania and a postdoctoral researcher at the University of Maryland Baltimore County. In the end, the team split up the Earth (excluding Antarctica) into 146 regions and sought archaeologists’ input on human activity in those regions at 10 different points in time. Some 700 responses came in.

Among their findings:

Foraging, defined as hunting, gathering and fishing, was common in most parts of the world 10,000 years ago, but was declining in more than half the world’s regions by 3,000 years ago.

Pastoralism — the raising of livestock — by 8,000 years ago had spread from some of its origin areas in Southwest Asia to arid environments like North Africa and Eurasia, where it was common by 4,000 years ago.

By 6,000 years ago, some form of agriculture was being practiced in nearly half of the world’s regions, and by 3,000 years ago, was widespread.

Farming is generally thought to “replace” hunting and gathering as a means of food production, but in some areas, agriculture occurred simultaneously with, or as a complement to, foraging.

"This type of work causes us to rethink the role of humans in environmental systems, particularly in the way we understand 'natural' environments," said Stephens, now a research analyst with the Environmental Law & Policy Center in Chicago and an affiliate at the Max Planck Institute. “Many people have realized for some time now that the study of long-term human-environment interactions must include archaeological knowledge, but our research and dataset really open the door to this sort of collaboration at global scale for the first time.”

"Many people have realized for some time now that the study of long-term human-environment interactions must include archaeological knowledge, but our research and dataset really open the door to this sort of collaboration at global scale for the first time."

Understanding the history of human impact on the environment has implications for addressing climate change, the authors say. With the release in early August of a report on land use from the United Nations' Intergovernmental Panel on Climate Change, it's clear that human impact is a critical issue for the future of the Earth, Stephens said. "But there is also a deep history of anthropogenic changes to the planet that has yet to be meaningfully incorporated in these discussions."

"It's time to get beyond the mostly recent paradigm of the Anthropocene and recognize that the long-term changes of the deep past have transformed the ecology of this planet, and produced the social-ecological infrastructures - agricultural and urban - that made the contemporary global changes possible," said co-author Erle Ellis of the University of Maryland Baltimore County, who initially proposed and helped design the study.

The ArchaeoGLOBE maps contain more information about some regions of the world than others, reflective of where much archaeological attention has been directed, researchers point out. That's due partly to the expertise of the archaeologists who participated in the current study, as well as the availability of resources and support for study in various locations. While extensive data was available from the Western and Northern hemispheres, study authors say, less-investigated regions clearly warrant more research.

"That can be facilitated by making information available," said Marwick, "who contributed expertise on Southeast Asia and assisted with putting all of ArchaeoGLOBE's materials online, accessible to anyone."

"A global dataset like this invites lots of interesting follow-up investigations that have not been possible before now. With all our data openly available, anyone anywhere can freely dig in and test out new ideas on a global scale," Marwick said.

As issues like climate change, global warming, and renewable energy dominate the national conversation, it's easy to assume these topics are exclusive to the modern world. But a huge collaborative study in Science reveals that early humans across the entire globe were changing and impacting their environments as far back as 10,000 years ago.

"Through this crowdsourced data, we can see that there was global environmental impact by land use at least 3,000 years ago," says Gary Feinman, MacArthur Curator of Anthropology at the Field Museum and one of the study's 250 authors. "And that means that the idea of seeing human impact on the environment as a newer phenomenon is too focused on the recent past."

Feinman says that to understand our current climate crisis, we need to understand the history of humans altering their environments.

The study, led by Lucas Stephens of the University of Pennsylvania, is a part of a larger project called ArchaeoGLOBE, where online surveys are used to gather information from regional experts on how land use has changed over time in 146 different areas around the world. Land use can be anything from hunting and gathering to farming to grazing animals. And as it turns out, many of the ways ancient people used the land weren't as "leave-no-trace" as many have imagined.

"About 12,000 years ago, humans were mainly foraging, meaning they didn't interact with their environments as intensively as farmers generally do," says Feinman. "And now we see that 3,000 years ago, we have people doing really invasive farming in many parts of the globe."

Humans in these time periods began clearing out forests to plant food and domesticating plants and animals to make them dependent on human interaction. Early herders also changed their surroundings through land clearance and selective breeding. While these changes were at varying paces, the examples are now known to be widespread and can provide insight on how we came to degrade our relationship with the Earth and its natural resources.

"We saw an accelerated trajectory of environmental impact," says Ryan Williams, associate curator and head of anthropology at the Field Museum and co-author of the study. "While the rate at which the environment is currently changing is much more drastic, we see the effects that human impacts had on the Earth thousands of years ago."

The results, however, are more optimistic than they seem. Now that researchers know the beginnings of environmental impact, they can use this data to study what solutions ancient civilizations used to mitigate the negative effects of deforestation, water scarcity, and more.

In addition to pointing out the history behind what most assume is a recent phenomenon, the study is one of the first of its kind to operate on such a large scale. Use of online resources and professional connections helped the project span across the world. The emphasis now, however, is on the parts we often miss.

"We need to invest in these regions that haven't been as intensively studied," says Williams. "If we incentivize and create opportunities for researchers there then you can just imagine what the results of the next study like this could be."

For a long time, war, environment, transportation and colonization prevented researchers from being able to work together and share their findings about certain parts of the world. As a result, today's archaeologists are still adding to and growing the network of expertise in these regions.

"What really got me here was not so much the results, although I think that the results provide a foundation to support what many archeologists suspected," says Feinman. "But I think the most innovative aspect of this was the whole research design. To gather information from 250 scholars and to make sure that the whole world was covered, that's really something."

While today's climate change and environmental destruction are happening more quickly and on a far larger scale than the world has ever seen, Feinman notes that this study helps provide a historical context to today's problems.

"There's such a focus on how the present is different from the past in contemporary science. I think this study provides a check, a counter-weight to that, by showing that yes, there have been more accelerated changes in land use recently, but humans have been doing this for a long time. And the patterns start 3,000 years ago," says Feinman. "It shows that the problems we face today are very deep-rooted, and they are going to take more than simple solutions to solve. They cannot be ignored."