Culture

Chinese scientists have recently shown how the tiny apex structure in plant leaves controls water drainage and confers an evolutionary advantage.

The research was conducted by Prof. JIANG Lei's team at the Technical Institute of Physical Chemistry of the Chinese Academy of Sciences. Results were published online in PNAS Jan. 13.

The leaf is the basis of plant survival. Through evolution, leaves have developed means to help control the absorption of sunshine and rain. The apex, for example, is where water is shed from the leaf and thus affects how droplets are shed.

In rainforests - which are characterized by high precipitation and humidity - understory plant leaves must drain water fast to avoid water-induced rot and damage. The most famous evolutionary advance in rainforest leaves is the drip tip. Although biologists have known since the 1980s that the drip tip facilitates fast drainage, they didn't understand the role the apex played in this process.

According to Dr. DONG Zhichao, the study's corresponding author, the tapered shape of the apex causes reduced capillary resistance in droplets. At the same time, the steep orientation of the apex increases the effect of gravity. Together, the apex's shape and orientation increase instability, thus enhancing water drainage.

For DONG, understanding this mechanism not only increases our appreciation of the role tiny structures play in plant survival, but also provides inspiration for upgrading drainage facilities and anticorrosion architecture.

This is especially important since dripping modes characterized by high frequency, low retention and low volume help reduce soil erosion.

Ancient architects intuitively understood the efficiency of drip tips, since drip tiles in oriental palace roofs and gargoyles in cathedrals exhibit excellent drainage and anticorrosion ability.

AURORA, Colo. (Jan. 15, 2020) - A byproduct of glucose called lactate, used by every cell in the body, may also prompt a mutated cell to become cancerous, according to new research from the University of Colorado Anschutz Medical Campus.

The study was published Tuesday in the journal Frontiers in Oncology.

"We discovered that lactate is a catalyst that triggers a mechanism in mutated cells necessary to continue the cancer forming process," said Iñigo San Millán, assistant professor of medicine at the University of Colorado School of Medicine and the University of Colorado Colorado Springs. "This opens a new door to better understand cancer at the metabolic level. It also means we might be able to target lactate with new therapies."

Lactate is not a waste product but a major source of energy for the cell, especially the mitochondria.

The role of lactate in cancer was first described nearly a century ago when Nobel Laureate Otto Warburg discovered that cancer cells were characterized not only by how quickly they consumed glucose, but a marked increase in lactate production. The process was called `The Warburg Effect.'

But exactly how it worked remained a mystery. In 2017, San Millán and his colleague from the University of California, Berkeley, George Brooks, PhD, published a hypothesis they believe explained for the first time the meaning and purpose of the Warburg Effect - to produce lactate for cancer formation purposes.

San Millán, who specializes in metabolism, and his team, sought to demonstrate this hypothesis. They exposed human breast cancer cells to glucose which then produced lactate. The lactate increased the expression of all the main mutated genes involved in breast cancer between 150-800%.

It's well known that not every mutated cell becomes cancerous and there has been speculation on what factors might `trigger' the expression of mutated genes. This study demonstrates that lactate is a key trigger. Now, San Millán and his team are reproducing this study in other cancers like small-cell lung cancer and non-small-cell lung cancer and finding similar results.

"Lactate, which used to be considered a waste product, turns out to be a major signaling molecule and a major regulator of the genes involved in cancer," San Millán said. "This is not the same behavior of lactate we get from doing exercise because that is quickly removed by the muscles and has positive signaling properties to improve physical fitness. The lactate produced in cancer stays put, is constantly being produced and acts as a catalyst to activate mutated genes into cancer. We still don't know these mechanisms but we are investigating them now."

Human muscle tissue is largely resistant to the formation of cancer. Exercise actually reduces the risks of some cancers and even could treat them therapeutically. San Millán has already started applying personalized exercise programs to cancer patients as part of their cancer rehabilitation and is exploring mechanisms by which exercise can help prevent and treat cancer.

He's also trying to find ways to block lactate from leaving the cancer cell.

"When lactate is produced it has to leave the cell through a transporter," he said. "We are trying to block the transporter as well as lactate production inside the cancer cell with different compounds. If you block the door, the lactate cannot leave and the cancer cell will burst."

But trying to block lactate in a human with a systemic drug would be deadly, so more targeted treatments are called for.

Furthermore, lactate from cancer cells seems to be a key player in keeping the immune system from attacking cancer cells, which is a typical characteristic of cancer.

San Millán and his team are currently doing trying to block lactate in different cancers implanted in mice.

"If we can effectively target lactate," he said. "We could possibly be taking a great step toward ending cancer."

La Trobe University researchers have found introducing a minimum unit price (MUP) of $1.30 per standard drink across Australia could dramatically reduce alcohol consumption.

Such a policy, already proven successful in Canada and Eastern Europe, could reduce drinking in Australia by 1.5 standard drinks per week on average and 12 drinks per week for harmful drinkers.

La Trobe Centre for Alcohol Policy Research (CAPR) health economist Dr Jason (Heng) Jiang said alcohol affordability in Australia has remained relatively unchanged over the last 30 years.

"In contrast, alcohol-related hospitalisations, emergency department and ambulance presentations, assaults and community-based specialised drug and alcohol treatment episodes have steadily increased in Australia."

On average, Australian drinkers consumed 14 standard drinks per week. Compared with moderate drinkers, harmful drinkers consumed a 17 times greater amount of alcohol per week (4.6 vs 80.7 standard drinks).

Average weekly alcohol spending by harmful drinkers was 11 times higher than spending by moderate drinkers ($178.40 vs $20.90). CAPR researchers also found 62 per cent of alcohol consumed by Australian drinkers was retail/take-away regular beer and bottle wine.

Dr Jiang analysed 2013 survey data of 1,789 Australian adults to reveal, for the first time, the effects of pricing policy initiatives on alcohol consumption in different drinking, income and age subpopulation groups.

"Minimum unit price policies primarily affect prices of low-cost beverages, nearly always sold off-premise, while a uniform excise tax would increase prices of almost all on- and off-sale beverages substantially, though with a smaller impact on spirits," Dr Jiang said.

The researchers' findings included:

- Introducing a MUP of $1.30 per standard drink across Australia (equal to the current floor price in the Northern Territory) could see alcohol consumption fall by 10.7 per cent (1.5 standard drinks per week) on average; 14.2 per cent (12 standard drinks per week) among harmful drinkers; and 3 per cent (0.2 standard drinks per week) among moderate drinkers

- Applying a uniform excise tax rate of $0.97 per standard drink (equal to the 2013 spirits tax rate) across all beverages could generate a similar impact to the $1.30 MUP policy, but with greater impact on moderate drinkers, with an 8.8 per cent fall in consumption (0.4 standard drinks per week)

- Introducing a MUP at $1.30 or $1.50 has the potential to improve health inequalities in Australia, as it could reduce consumption particularly among harmful drinkers and lower income drinkers, with comparatively smaller impacts on moderate drinkers and higher income drinkers

"Although applying a uniform tax rate across all beverages or introducing a $1.30 minimum unit price across all states and territories could have a similar impact on overall alcohol consumption, the beneficiaries are quite different," Dr Jiang said.

"The former will increase tax revenue for the federal government while the latter will only increase sales revenue, benefitting alcohol retailers, wholesalers and/or producers.
"Our findings show it's time we had a discussion on alcohol pricing or tax reform in Australia."

At around 1 a.m. local standard time on April 29, 2017, a fireball flew over Kyoto, Japan. Compared to other fireballs spotted from Earth, it was relatively bright and slow. Now, scientists have determined not only what the fireball was, but also where it came from.

"We uncovered the fireball's true identity," says Toshihiro Kasuga, paper author and visiting scientist at the National Astronomical Observatory of Japan and Kyoto Sangyo University. "It has a similar orbit to that of the near-Earth asteroid 2003 YT1, which is likely its parent body."

2003 YT1, a binary asteroid first detected in 2003, appears to have been active in the past, meaning it fissured and released dust particles, such as the one responsible for the 2017 fireball. It does not currently show any activity, though, according to Kasuga. However, the researchers found that the orbit, estimated radiant point, velocity and appearance date of the 2017 fireball are all consistent with dust particles that originated from 2003 YT1.

"The potential break-up of the rock could be dangerous to life on Earth," Kasuga says. "The parent body 2003 YT1 could break up, and those resulting asteroids could hit the Earth in the next 10 million years or so, especially because 2003 YT1 has a dust production mechanism."

The researchers found that this dust production mechanism, or the asteroid's likelihood of releasing dust and rock particles, stems from its rotational instability in a process called the YORP effect. When the asteroid is warmed by the Sun, the energy results in a small thrust, which can produce a corresponding recoil, depending on the gravitational pull and other physical variables. The recoil can twist the asteroid, introducing a rotational change. The change can be at physical odds with the gravity and/or other forces, and force the asteroid to physically break -- even just a little, a process which produces dust.

"The released particles can enter Earth's atmosphere and appear as fireballs, which is exactly what happened in 2017," says Kasuga.

According to Kasuga, that particular fireball was not a threat to Earth, as it was estimated to only be a few centimeters in size. Something so small would burn up before it reached the surface.

"The 2017 fireball and its parent asteroid gave us a behind-the-scenes look at meteors," says Kasuga. "Next, we plan to further research predictions for potentially hazardous objects approaching the Earth. Meteor science can be a powerful asset for taking advanced steps towards planetary defense."

One in six women experience long-term post-traumatic stress following miscarriage or ectopic pregnancy.

This is the finding of the largest ever study into the psychological impact of early-stage pregnancy loss, from scientists at Imperial College London and KU Leuven in Belgium.

The research, published in the journal American Journal of Obstetrics and Gynaecology, studied over 650 women who had experienced an early pregnancy loss, of whom the majority had suffered an early miscarriage (defined as pregnancy loss before 12 weeks), or an ectopic pregnancy (where an embryo starts to grow outside the womb and is not viable).

The study revealed that one month following pregnancy loss, nearly a third of women (29 per cent) suffered post-traumatic stress while one in four (24 per cent) experienced moderate to severe anxiety, and one in ten (11 per cent) had moderate to severe depression.

Nine months later, 18 per cent of women had post-traumatic stress, 17 per cent moderate to severe anxiety, and 6 per cent had moderate to severe depression.

The team behind the research, funded by the Imperial Health Charity and the Imperial NIHR Biomedical Research Centre, call for immediate improvements in the care women receive following an early-stage pregnancy loss.

Professor Tom Bourne, lead author of the research from Tommy's National Centre for Miscarriage Research at Imperial College London said: "Pregnancy loss affects up to one in two women, and for many women it will be the most traumatic event in their life. This research suggests the loss of a longed-for child can leave a lasting legacy, and result in a woman still suffering post-traumatic stress nearly a year after her pregnancy loss."

Professor Bourne, who is also a Consultant Gynaecologist, added: "The treatment women receive following early pregnancy loss must change to reflect its psychological impact, and recent efforts to encourage people to talk more openly about this very common issue are a step in the right direction. Whilst general support and counselling will help many women, those with significant post-traumatic stress symptoms require specific treatment if they are going to recover fully. This is not widely available, and we need to consider screening women following an early pregnancy loss so we can identify those who most need help."

The research follows an earlier pilot study in 2016, which investigated the psychological impact of early-stage pregnancy loss in 128 women one and three months after miscarriage or ectopic pregnancy.

One in four pregnancies ends in miscarriage - most often before or around 12 weeks. Estimates suggest there are 250,000 miscarriages every year in the UK, and around 11,000 emergency admissions for ectopic pregnancies. The latter always result in pregnancy loss, as an embryo grows in an area outside of the womb and is unable to develop.

In the study 537 women had suffered a miscarriage before 12 weeks of pregnancy, while 116 had suffered an ectopic pregnancy.

The women in the study attended the Early Pregnancy Assessment Units at three London hospitals - Queen Charlottes and Chelsea, St Mary's, and Chelsea and Westminster.

All were asked to complete questionnaires about their emotions and behaviour one month after pregnancy loss, then again three and nine months later.

Their responses were compared to 171 women who had healthy pregnancies. The results revealed the latter women's levels of psychological symptoms were significantly lower than those found in women who had suffered early pregnancy loss.

The women in the study who met the criteria for post-traumatic stress reported regularly re-experiencing the feelings associated with the pregnancy loss, and suffering intrusive or unwanted thoughts about their miscarriage. Some women also reported having nightmares or flashbacks, while others avoided anything that might remind them of their loss.

The authors caution the study used a questionnaire for screening for post-traumatic stress, but formal diagnosis of post-traumatic stress disorder would require a clinical interview.

The team also explain that women who were already experiencing symptoms of post-traumatic stress and depression may have been more likely to respond to the questionnaire, which could mean the number of women suffering psychological symptoms may appear higher.

However, they add that the fact that such a large proportion were experiencing symptoms suggests many women could be suffering in silence. Dr Jessica Farren, first author of the research from Imperial College, and Obstetrician and Gynaecologist, said: "Post-traumatic stress can have a toxic effect on all elements of a person's life - affecting work, home and relationships."

"We have made significant progress in recent years in breaking the silence around mental health issues in pregnancy and postnatally, but early pregnancy losses are still shrouded in secrecy, with very little acknowledgement of how distressing and profound an event they are. Many women don't tell colleagues, friends or family they are pregnant before the 12-week scan, leaving them feeling unable to discuss their emotions if they suffer a pregnancy loss. We also know partners can suffer psychological distress following miscarriage or ectopic pregnancy, and are investigating this in ongoing research."

The team's research will also now focus on identifying which women are at risk of developing psychological symptoms after pregnancy loss, the impact of early pregnancy loss on partners and also the best type of treatments and how to deliver these.

Ian Lush, Chief Executive of Imperial Health Charity, said: "As the dedicated charity for the Imperial College Healthcare NHS Trust hospitals, we are committed to supporting pioneering research that leads to real improvements in patient care through our annual research fellowships programme. "Dr Farren's study clearly shows that a miscarriage or ectopic pregnancy can have profound and long-lasting impacts on women's mental health and we look forward to seeing how this important research can be translated into better care for patients and their families in the future."

Jane Brewin, Chief Executive of Tommy's comments, said: "For too long women have not received the care they need following a miscarriage and this research shows the scale of the problem. Miscarriage services need to be changed to ensure they are available to everyone, and women are followed up to assess their mental wellbeing with support being offered to those who need it, and advice is routinely given to prepare for a subsequent pregnancy."

Kate Rawson, an actor and playwright, experienced two miscarriages in 2014 and 2015, one at 8 weeks and one at 11 weeks. She has written a radio play about recurrent miscarriage called Little Blue Lines. Here she discusses her experience:

"After my first miscarriage I was numb. I did not know how to react or who to approach. I did not know if it was grief that I was feeling, or if that was even a valid response to have about losing something so 'small'. So I tried to believe reassuring words ('it's not your fault; you can try again; you've got time; it's just one of those things.')

The second time it happened I knew something was wrong immediately, just a faint pink patch in my pants, a slight cramping feeling. Then dread and anxiety at what was to come, and guilt at what I could have done to cause it; sadness for myself, but also my husband, my family, my friends who would have to do all those sad faces and texts and calls again. The physical miscarriage was a huge shock, one I was absolutely not prepared for and I will never forget it.

I tried to 'move on' as advised. 'Trying again' was full of anxiety that got worse when I fell pregnant for the third time. Happily that resulted in a healthy full term birth, but the first trimester was extremely stressful, for both myself and my husband. I struggled to keep perspective and flitted between wanting this baby more than anything else to wishing I would just bleed and get the awful thing over with and my life back.

It was only after my son was born I realized the enormity of what I had been through, and the need to process it - there are support groups at my hospital now but there was nothing available to me at the time - so I wrote about it."

In mammals, pair bonds are very rare, one of the few exceptions being the red titi monkeys of South America. These relatively small tree dwellers live in pairs or small family groups and are characterized by the fact that the males take intensive care of their offspring. A team of researchers from the German Primate Center - Leibniz Institute for Primate Research has now investigated how pair relationships work in titi monkeys. Their results support the so-called "male-services hypothesis": Males provide a useful service by taking more care of the offspring and defending the territory against intruders, while the females are more involved in relationship management and, for example, seek the proximity of their partner more often (Journal of the Royal Society Open Science).

Less than ten percent of all mammalian species live in pair relationships, although the latter are difficult to define. Do the animals only share a territory or is it a long-term relationship based on mutual contact? And if so, how is this relationship maintained? To find this out, behavioral biologists from the German Primate Centre (DPZ) have studied seven groups of red titi monkeys accustomed to the presence of humans in the Peruvian Amazon rainforest near the DPZ research station Quebrada Blanco. Titi monkeys are a textbook example of pair living in mammals. Pairs stay together for many years and males are intensively involved in raising their young. The young are almost exclusively carried by the father and are given to the mother only for suckling. In addition, the fathers play with their children and share their food more often with them than the mothers do.

The researchers wanted to find out what advantages couple life brings for both males and females and what contribution the respective sexes make to the relationship. To do this, they observed the animals over a time span of two seven-month periods from morning to night and noted which animal was seeking the proximity of its partner, who was grooming whom, and which animals were involved in confrontations with intruders.

Females maintain the relationship, males offer services

"We have observed that the females, especially after giving birth, are increasingly concerned with maintaining relationships, i.e. actively seeking the proximity of their partner and grooming their fur," says Sofya Dolotovskaya, PhD student at the German Primate Center and first author of the study. The males, on the other hand, have become increasingly involved in conflicts with intruders. "This behavior is in line with the 'male-services hypothesis', which states that females are mainly concerned with being close to their partner while the latter provides useful services, such as defense against intruders or rearing the young," says Eckhard W. Heymann, scientist at the German Primate Center and head of the DPZ research station Estación Biológica Quebrada Blanco in Peru. "Our results support the hypothesis that the commitment of males for rearing their young is an important factor in maintaining pair relationships." In further investigations it is currently examined whether these pair relationships are accompanied by monogamous mating behavior.

Some forms of camouflage have evolved in animals to exploit a loophole in the way predators perceive their symmetrical markings. The University of Bristol findings, published in Proceedings of the Royal Society B today [15 Jan], describe how animals have evolved to mitigate this defensive disadvantage in their colouration.

Most animals with high-contrast markings have bilaterally symmetrical camouflage. For example, both butterflies and frogs have body shapes which can be divided along a midline into left and right sides with a mirror image on each side. However, this new study, led by researchers from Bristol's Camo Lab, show that camouflaged symmetrical animals with patterns near their midline make themselves more detectable to predators.

To test the theory whether evolution has led animals to reduce the symmetry found in their camouflage to overcome this, researchers combined field and lab experiments and then conducted a 'natural pattern analysis' to investigate whether evolution has led animals to reduce this.

Benito Wainwright, the study's lead researcher and a PhD student from Bristol's School of Biological Sciences, explains: "Previous artificial predation experiments in the laboratory and the field had demonstrated that symmetrical colouration impedes the efficacy of camouflage. This is because a symmetrical midline makes the animal more noticeable to its predators who can compare closer together symmetrical patterns more easily.

"While this is paradoxical because most camouflaged animals have symmetrical colours and patterns, this is assumed to be because of genetic and developmental constraints. We wanted to test whether animals have evolved to mitigate this constraint and exploit a loophole in the way predators perceive symmetrical patterns."

The team conducted the first two experiments to put ideas from perceptual psychology into the context of animal colours and patterns, used the theory suggested by the results of these two experiments, and then applied them to the 'Natural Pattern Analysis' to see whether this is actually the case in nature. The analysis enabled the team to measure distances of markings from the midline point of the wings of 36 species of moth and butterfly using real specimens from museums, field guides and photographs. The results from this process complemented the findings of the first two human and wild bird experiments and showed that camouflage patterns tended to be away from the midline, thereby reducing the noticeability of the symmetry.

Benito, said: "Our study is one of the first to put results from classic artificial target experiments into a natural context by using real animal specimens. Our results have implications for the protective colouration of a wide variety of cryptically-coloured animals which wish to remain undetected from both visually guided mammalian and avian predators and should therefore prompt further studies which aim to combine experimental work with observations of real animal colours and patterns."

Areas of high HIV prevalence, known as 'hotspots', do not necessarily fuel the epidemic in the wider population, say researchers.

Hotspots are often targeted for intense HIV control interventions, including treatment and prevention, to maximise their effect and reach the people in greatest need first.

These strategies often assume that hotspots are also sources of disease transmission to other areas, and that targeting hotspots will have the added indirect benefit of reducing new HIV infections in the wider population.

However, a new study by an international team of researchers, led by scientists at Imperial College London and the Rakai Health Sciences Program in Uganda, suggests this is not necessarily the case. Instead, the research shows that some hotspots seed very few infections to neighbouring communities and actually receive more infections from outside.

The study was carried out with 'hotspot' fishing communities on the shores of Lake Victoria in Uganda, where approximately 40 percent of the population are infected with HIV, amongst the highest HIV prevalence levels in the world. The team mapped how disease was transmitted between these communities and larger inland communities with much lower HIV prevalence.

Contrary to expectation, they found that more HIV infections were driven by the inland communities with lower HIV prevalence than by the HIV hotspots. The results are published today in Lancet HIV.

Lead researcher Dr Oliver Ratmann, from the Department of Mathematics at Imperial, said: "Our finding shows that HIV disease dynamics are not as obvious as they may seem, and advises caution against equating and stigmatizing hotspots as population groups that drive HIV spread in Africa."

Co-author of the study Dr Kate Grabowski, from the Johns Hopkins Bloomberg School of Public Health, added: "We were really surprised by the findings. Lake Victoria fishing communities have long been assumed to be drivers of transmission in neighbouring East African communities; however, our results show that is likely not the case."

The team used recent advances in molecular biology and advanced statistics to map the transmission of HIV between people - the chain of infection events that lead to someone getting the disease.

This is possible because the virus changes subtly as it is passed around. Previously, scientists using this information had been able to say if the disease had likely passed between two people, but not which direction was more probable.

The new study was conducted as part of the PANGEA-HIV consortium, an international partnership to use viral sequence analysis to assess the transmission of HIV in Africa funded by the Bill and Melinda Gates Foundation.

The team deep-sequenced the genome of the virus from more than 2,500 HIV-positive people in Lake Victoria hotspots and surrounding inland communities between 2010-2015. They integrated this information with surveys about migration in the region, to accurately track disease spread in a highly mobile population.

They found that only 5.4 percent of infections in the region occurred between the hotspots and inland communities. Of these, nearly three times as many new infections occurred from inland communities into hotspot communities, rather than out from hotspot communities.

Dr Ratmann said: "It has long been assumed that the hotspot communities around Lake Victoria were a 'source' of HIV infections, but it seems the opposite is true, and they are a 'sink', with more infections originating outside the hotspot."

The researchers suggest this surprising result might be because the fishing communities are relatively small compared to the larger inland population, and because of migration dynamics related to local economies and social context.

Despite their much lower proportions of HIV-positive individuals, inland communities have higher overall numbers of infected people, who are also more likely to move to the fishing communities than vice versa.

However, they also caution this is one case study and similar studies in other regions may reveal different patterns. They are currently repeating the research further north on the shore of Lake Victoria to test the robustness of their findings.

The federal government has allocated only about 2 percent of its transportation funds to encourage walking and cycling, not nearly enough to make a significant difference, according to Ralph Buehler, associate professor and chair of the urban affairs and planning program in the Virginia Tech School of Public and International Affairs.

In a recently released study of National Household Travel Surveys from 2001 and 2017 designed to estimate the frequency, duration, and distance of walking and cycling per capita, Buehler and his collaborators, John Pucher from Rutgers University and Adrian Bauman from the University of Sydney, found only a slight increase in walking and no increase in cycling.

"It is not at all surprising that the small increase in walking was in dense, urban cities like Boston, New York City, Philadelphia, and Washington, D.C., where measures have been taken to improve infrastructure and programs and policies have been adopted to make walking and cycling easier and safer," said Buehler.

The study showed the most significant increase in walking was among well-educated adults 25-64 years.

While walking rates are roughly the same for men and women, cycling remains highest among white, higher-income males. In fact, three times more men than women are likely to cycle, Buehler said.

"In general, women will only cycle if they think the entire ride will be safe," said Buehler. "If they perceive that there will be any danger at all along the way they will resist."

Another obstacle to increasing walking and cycling in the U.S., said Buehler, is that driving is still very attractive and, aside from urban areas, parking is typically free or inexpensive. The study found that when compared to individuals in households without cars, those in households with at least one car were less than half as likely to cycle in 2001 and only slightly more than a third as likely in 2017. Rates were even lower for households with two cars and lowest for those with three or more cars.

The study was recently published online in the March issue of the Journal of Transport and Health.

"Public health researchers know that walking and cycling have many health benefits, as well as being environmentally, socially, and economically sustainable means of urban travel," said Buehler, who noted that one big advantage of these physical activities is that they can easily be integrated into daily routines.

Walking and cycling are natural, cheaper, and more utilitarian than exercise that requires more structured visits to gyms, fitness centers, or swimming pools, he said.

"Because they have health implications, it is important that there be equity when improving conditions and facilities connected to them. Governments need to work on a much greater, nationwide scale and especially with underserved communities to plan and implement safer traffic lights, crosswalks and bike lanes, and bike parking facilities," said Buehler.

"Too little has been done outside of wealthier areas to support more walking or cycling," Buehler said, citing Ward 7 and Ward 8 in Washington, D.C., as an example.

Buehler and his team found that both walking and cycling decreased most among one demographic: 5 to 15 year-olds.

"When you think about how walking and cycling can favorably impact health and how obesity and related problems are on the rise among U.S. adolescents, this is a troubling finding," Buehler said.

While some of the decline in this age group can be attributed to parents' fear of "stranger danger" and the fact that technology allows kids to connect to each other with no need for face-to-face encounters, Buehler said that schools could play an important role in encouraging cycling by teaching a course much like its driver education programs.

"If both parents and children better understand the health benefits cycling offers and learn the 'rules' of cycling, they may be more willing to accept it as a practical, healthier, and even more enjoyable mode of transportation," Buehler said.

Another important target group, said Buehler, is seniors. "Nonexistent, unconnected, or low-quality sidewalks increase the risk of falls by pedestrians, with particularly serious health consequences for seniors," he said. "But given their greater vulnerability when driving in traffic, it is quite likely that they can be encouraged to walk if ensured of safe, convenient, and pleasant walking facilities."

MALIBU, Calif. January 10, 2019-- HRL Laboratories, LLC, researchers have published results showing that targeted transcranial electrical stimulation during slow-wave sleep can improve metamemories of specific episodes by nearly 20% after only one viewing of the episode, compared to controls. Metamemory describes the sensitivity of whether memories are recalled accurately or not, such as during eyewitness testimony.

Unique patterns of transcranial electrical stimulation can be cued during the sleep phase called slow-wave sleep to boost consolidation of new memories into the brain's permanent long-term memory. Known as spatiotemporal amplitude-modulated patterns or STAMPS, these stimulation patterns can be targeted to affect particular memories. In immersive virtual reality experiments, one-minute episodes were first paired with arbitrary STAMPs once during viewing. With subsequent stimulation during sleep, targeted memories were measurably improved after just one viewing. Before this study, general belief was that targeting individual naturalistic memories would require invasive interventions at the single neuron scale in the hippocampus.

"Our results suggest that, unlike relatively localized brain circuits responsible for regulating mood and movement, episodic memories are processed by a much more widespread network of brain areas," said HRL principal investigator and lead author Praveen Pilly. "We believe our study will pave the way for next-generation transcranial brain-machine interfaces that can boost learning and memory in healthy humans for real-world tasks, such as language attainment or piloting skills. Such a non-invasive approach can also potentially benefit a majority of patients with learning and memory deficits at much lower cost and risk than required for implanting intracranial electrode arrays. It could also be possible to enhance the efficacy of exposure behavioral therapy with immersive virtual reality using STAMP-based tagging and cueing for the treatment of PTSD."

New York, NY--January 13, 2020--A recent decision by the National Transpiration Safety Board (NTSB) on the March 2018 Uber crash that killed a pedestrian in Arizona split the blame among Uber, the company's autonomous vehicle (AV), the safety driver in the vehicle, the victim, and the state of Arizona. With the advent of self-driving cars, the NTSB findings raise a number of questions about the uncertainty in today's legal liability system. In an accident involving an AV and a human driver, who is liable? If both are liable, how should the accident loss be apportioned between them?

AVs remove people from the hands-on task of driving and thus pose a complex challenge to today's accident tort law, which primarily punishes humans. Legal experts anticipate that, by programming driving algorithms, self-driving car manufacturers, including car designers, sensor vendors, software developers, car producers, and related parties who contribute to the design, manufacturing, and testing, will have a direct influence on traffic. While these algorithms make manufacturers indispensable actors, with their product's liability potentially playing a critical role, policy makers have not yet devised a quantitative method to assign the loss between the self-driving car and the human driver.

To tackle this problem, researchers at Columbia Engineering and Columbia Law School have developed a joint fault-based liability rule that can be used to regulate both self-driving car manufacturers and human drivers. They propose a game-theoretic model that describes the strategic interactions among the law maker, the self-driving car manufacturer, the self-driving car, and human drivers, and examine how, as the market penetration of AVs increases, the liability rule should evolve.

Their findings are outlined in a new study to be presented on January 14 by Sharon Di, assistant professor of civil engineering and engineering mechanics, and Eric Talley, Isidor and Seville Sulzbacher Professor of Law, at the Transportation Research Board's 99th Annual Meeting in Washington, D.C

While most current studies have focused on designing AVs' driving algorithms in various scenarios to ensure traffic efficiency and safety, they have not explored human drivers' behavioral adaptation to AVs. Di and Talley wondered about the "moral hazard" effect on humans, whether with exposure to more and more traffic encounters with AVs, people might be less inclined to exercise "due care" when faced with AVs on the road and drive in a more risky fashion.

"Human drivers perceive AVs as intelligent agents with the ability to adapt to more aggressive and potentially dangerous human driving behavior," says Di, who is a member of Columbia's Data Science Institute. "We found that human drivers may take advantage of this technology by driving carelessly and taking more risks, because they know that self-driving cars would be designed to drive more conservatively."

The researchers used game theory to model a world with interacting players who try to select their own actions to optimize their own goals. The players--law makers, AV manufacturers, AVs, and human drivers--have different goals in the transportation ecosystem. Law makers want to regulate traffic with improved efficiency and safety, self-driving car manufacturers are profit-driven, and both self-driving cars and human drivers interact on public roads and seek to select the best driving strategies. To capture the complex interaction among all the players, the researchers applied game theory methods to see which strategy each player settles on, so that others will not take advantage of his or her decisions.

The hierarchical game helped the team to understand the human drivers' moral hazard (how much risk drivers might decide to take on), the AV manufacturer's impact on traffic safety, and the law maker's adaptation to the new transportation ecosystem. They tested the game and its algorithm on a set of numerical examples, offering insights into behavioral evolution of AVs and HVs as the AV penetration rate increases and as cost or environment parameters vary.

The team found that an optimally designed liability policy is critical to help prevent human drivers from developing moral hazard and to assist the AV manufacturer with a tradeoff between traffic safety and production costs. Government subsidies to AV manufacturers for the reduction of production costs would greatly encourage manufacturers to produce AVs that outperform human drivers substantially and improve overall traffic safety and efficiency. Moreover, if AV manufacturers are not regulated in terms of AV technology specifications or are not properly subsidized, AV manufacturers tend to be purely profit-oriented and destructive to the overall traffic system.

"The tragic fatality in Arizona involving a self-driving automobile elicited tremendous attention from the public and policy makers about how to draw the lines of legal liability when AVs interact with human drivers, cyclists, and pedestrians," Talley adds. "The emergence of AVs introduces a particularly thorny type of uncertainty into the status quo, and one that feeds back onto AV manufacturing and design. Legal liability for accidents between automobiles and pedestrians typically involves a complex calculus of comparative fault assessments for each of the aforementioned groups. The introduction of an autonomous vehicle can complicate matters further by adding other parties to the mix, such as the manufacturers of hardware and programmers of software. And insurance coverage distorts matters further by including third party stakeholders. We hope our analytical tools will assist AV policy-makers with their regulatory decisions, and in doing so, will help mitigate uncertainty in the existing regulatory environment around AV technologies."

Di and Talley are now looking at multiple AV manufacturers that target different global markets with different technological specifications, making the development of legal rules even more complex.

"We know that human drivers will take more risks and develop moral hazard if they think their road environment has become safer," Di notes. "It's clear that an optimal liability rule design is crucial to improve social welfare and road safety with advanced transportation technologies."

New research co-authored by Yanwen Wang, an assistant professor in the UBC Sauder School of Business, reveals that the resale ticket market also appeals to sports fans who normally buy season tickets.

Resale ticket markets -- also known as secondary ticket markets -- allow season ticket holders to recoup costs by selling unneeded tickets, as well as creating an alternative supply of tickets that reduce the need for fans to commit to a season's pass.

It turns out this isn't just beneficial for fans - it also boosts team revenues.

"Since sports teams earn significant portions of their revenues from season ticket holders, we wanted to find out how secondary markets actually impact their behaviour," said Wang. "Our research reveals that sports fans are more likely to purchase season tickets when there is a secondary market because they know they can sell them easily. This in turn increases a sport team's revenue by at least seven per cent per year."

Wang says this is a conservative estimate as it does not include incremental revenue sources such as parking, concessions or merchandise sales. She adds that given sports teams have high fixed costs, low marginal costs, and perishable inventory like food served at concessions, the increased revenue could have significant implications for a team's profitability.

For this study, Wang and her team examined a major league baseball team in the U.S. They analyzed 1,924 customers who purchased season ticket packages at least once over a six-year period and tracked their behaviour for 481 games. They looked at the ticket type, price paid, ticket usage and ticket resales to find out whether each ticket was used for attendance, listed, resold or forgone.

Among the researchers' other discoveries was constraints on ticket pricing such as minimum price floors­, which is pre-determining the lowest price in which a ticket could be sold at, have an adverse impact on season ticket sales.

"This is a complex issue because price floors may be motivated by a sports team's desire to protect brand equity," said Wang. "However, the teams must find ways to balance brand maintenance goals against the benefits of providing more value to the team's hardcore fans."

The researchers hope their study will encourage future research such as how data from the resale market can inform ticket pricing decisions, as well the effect on non-sports events like concerts.

Parasitic weeds are among the world's most economically damaging agricultural pests. They use an organ called the haustorium to build connections with host plants and draw nutrients from them.

While the majority of research on parasitic plant biology and control of root parasitic weeds has been heavily focused on seed germination, scientists at UC Davis focused on the development of haustorium and published their findings in Phytopathology.

"We targeted chemicals that may affect signaling pathways during haustorium development and performed small molecule screens in the model parasitic plant Triphysaria to assay potential haustorium inhibitors," said corresponding author John Yoder. "Several novel inhibitors are identified in our article."

Yoder and his colleagues demonstrated that disrupting redox signaling can effectively prevent haustorium initiation and some inhibitor chemicals do not affect root growth, making them a potential growth method against parasitic weeds.

Their research uniquely screens the largest number of chemicals directly on parasitic plants. They also did a thorough search of the chemical and physical properties of the chemicals in the redox library and DMBQ analog library from PubChem and EPA databases. This information is available in the supplemental files included with their article, "Small-Molecule Screens Reveal Novel Haustorium Inhibitors in the Root Parasitic Plant Triphysaria versicolor" published in the November issue of Phytopathology.

"Biology is complicated," Yoder said. "Many structural analogs of DMBQ induce the expression of genes related to haustorium development but do not activate haustorium initiation. Redox regulations are not limited to haustorium development but also involved in most processes in plant growth, development, and stress response."

Additional research on specific control of redox reactions during haustorium development is still needed to make use of discoveries in this article as potential control methods against parasitic weeds.

Most research has focused on the oral, skin, and gut microbiomes, but bacteria, viruses, and fungi living within our reproductive systems may also affect sperm quality, fertilization, embryo implantation, and other aspects of conception and reproduction. Yet, according to a review published January 14 in the journal Trends in Ecology & Evolution, little is known about the reproductive microbiome.

What we do know is that there are examples of microbes affecting sexual health and fertility across the animal kingdom, and that these impacts seem to have important consequences for reproductive biology and behavior.

In human men, certain species of bacteria are associated with higher- or lower-quality sperm samples, while higher quantities of bacteria are more prevalent in semen samples from infertile than fertile men.

A study of primates showed that vaginal microbiomes are more diverse in species in which females have more than one sexual partner. Similar findings have been reported in deer mice and in common lizards.

Male mallards with more colorful bills produce semen better able to kill bacteria, leading researchers to speculate that female mallards sometimes choose partners with more colorful bills to reduce the risk of STDs, minimize disruption to their own microbiome, and ensure they receive high quality sperm.

Male bedbugs inseminate a female by piercing her abdomen. Recent work indicates that females, which can die from infections caused by microbes on the male copulatory organ, ramp up their immunological defenses ahead of mating.

In black garden ants, the testes of virgin males appear to favor microbial growth while the sperm-storage organs of virgin females strongly inhibit microbial growth.

Male red junglefowl, a wild ancestor of the domestic chicken, produce more proteins with antimicrobial effects in their ejaculate over successive matings--possibly to better protect dwindling numbers of sperm.

"Reproductive microbiomes can have significant effects on the reproductive function and performance of both males and females," says senior author Tommaso Pizzari, a zoologist at the University of Oxford. "These studies also shed light on the role of the reproductive microbiome in sexual selection, mating system, and sexual conflict."

While research has begun to link alterations in the vaginal microbiome to adverse pregnancy outcomes in humans, it's unclear how the male reproductive microbiome affects fertility and reproductive success, says first author Melissah Rowe (@melissah_rowe), an evolutionary ecologist who studies reproductive biology and behavior at the Netherlands Institute of Ecology.

"This is surprising, because research has shown that bacteria can damage sperm form and function, and that damaged sperm can contribute to pregnancy failure" Rowe says.

Many major questions remain. Rowe and Pizzari are intrigued by how some microbes benefit one sex or species while harming another. For example, Lactobacilllus--associated with a healthy vaginal microbiome in women and high-quality semen in men--seems to negatively affect sperm-swimming speed in chickens. But the authors say that the combination of sequencing advances, genomic resources, and investigations of host sexual behavior will likely lead to more discoveries soon.

A common bacteria that boosts digestive health can slow - and even reverse - build-up of a protein associated with Parkinson's, new research suggests.

Building on previous research linking brain function to gut bacteria, this study in a Parkinson's model of roundworms, identified a probiotic - or so-called good bacteria - which prevents the formation of toxic clumps that starve the brain of dopamine, a key chemical that coordinates movement. These new findings could pave the way for future studies that gauge how supplements such as probiotics impact the condition.

In the brains of people with Parkinson's, alpha-synuclein protein misfolds and builds up, forming toxic clumps. These clumps are associated with the death of nerve cells responsible for producing dopamine. The loss of these cells causes the motor symptoms associated with Parkinson's, including freezing, tremors and slowness of movement.

The researchers from the Universities of Edinburgh and Dundee used roundworms altered to produce the human version of alpha-synuclein that forms clumps. They fed these worms with different types of over-the-counter probiotics to see if bacteria in them could affect the formation of toxic clumps.

The scientists found that a probiotic called Bacillus subtilis had a remarkable protective effect against the build-up of this protein and also cleared some of the already formed protein clumps. This improved the movement symptoms in the roundworms. The researchers also found that the bacteria was able to prevent the formation of toxic alpha-synuclein clumps by producing chemicals that change how enzymes in cells process specific fats called sphingolipids.

The study by Goya ME, Xue F, et al, published in the journal Cell Reports, was funded by Parkinson's UK, the EMBO and the European Commission. It is the latest in a number of recent studies which have found a link between brain function and the thousands of different kinds of bacteria living in the digestive system, known as the gut microbiome. Other studies into mice have found that the gut microbiome has an impact on the motor symptoms.

Lead researcher, Dr Maria Doitsidou, from the Centre for Discovery Brain Sciences at the University of Edinburgh, said: "The results provide an opportunity to investigate how changing the bacteria that make up our gut microbiome affects Parkinson's. The next steps are to confirm these results in mice, followed by fast-tracked clinical trials since the probiotic we tested is already commercially available."

Dr Beckie Port, Research Manager at Parkinson's UK, said: "Parkinson's is the fastest growing neurological condition in the world. Currently there is no treatment that can slow, reverse or protect someone from its progression but by funding projects like this, we're bringing forward the day when there will be.

"Changes in the microorganisms in the gut are believed to play a role in the initiation of Parkinson's in some cases and are linked to certain symptoms, that's why there is ongoing research into gut health and probiotics.

"The results from this study are exciting as they show a link between bacteria in the gut and the protein at the heart of Parkinson's, alpha synuclein. Studies that identify bacteria that are beneficial in Parkinson's have the potential to not only improve symptoms but could even protect people from developing the condition in the first place."