Brain

UNIVERSITY PARK, Pa. -- The office holiday party loses its luster in light of new study findings from researchers at Penn State and Ohio State demonstrating that incidences of unwanted sexual attention are increased at these and other "fun" work events. This sexual harassment may be reduced, however, when these events are held during normal office hours, when attendance is optional and when employees are allowed to bring guests.

"Our research suggests that managers can take specific measures to help protect their employees from unwanted sexual attention at fun work events," said Michael J. Tews, associate professor of hospitality management, Penn State.

The team defined fun work events as those organized by employers and intended to bring enjoyment to employees.

Published in a recent issue of Employee Relations, the researchers gave online surveys to two groups of employees located throughout the United States -- 308 restaurant employees and 338 employees across different industries. They asked the participants about their involvement in five types of fun activities -- holiday parties and picnics, team building activities, competitions, public celebrations of work achievements and public recognition of personal milestones such as birthdays.

Survey respondents then ranked several statements on a five-point scale ranging from "never" to "almost daily," including, "Someone at work stared at you in a sexually inappropriate way," "Someone at work repeatedly asked you out, despite rejection" and "Someone at work touched you in a way that made you feel uncomfortable."

"We found that for both groups -- the restaurant employees and all the other types of employees -- unwanted sexual attention was significantly higher during fun activities than during normal work-related activities," said Phillip Jolly, assistant professor of hospitality management.

The researchers also included survey questions aimed at exploring the influence, if any, of mandatory participation, evening or weekend timing, presence of non-employees and alcohol use on the occurrence of sexual harassment at fun work events.

They found that sexual harassment was particularly high when participation in fun activities was mandatory and when the activities were held outside of normal work hours.

"It could be that some individuals perceive their autonomy as unfairly constrained when they are required to attend off-hours events," said Tews. "As a result, they may seek to remedy the situation through counterproductive work behavior, such as unwanted sexual attention."

In contrast, the team found that incidences of unwanted sexual attention were lower when fun activities included non-employees, such as friends and family.

"Friends and family may serve as buffers between targets and potential harassers," said Jolly.

Interestingly, the researchers did not find a significant impact of alcohol on unwanted sexual attention.

"We thought the presence of alcohol would be related to greater unwanted sexual attention because it can reduce inhibitions and blur the lines between appropriate and inappropriate workplace conduct, but we did not observe a relationship between the two," said Tews.

Tews said, "We hope that this research helps provide guidance to managers so that fun, which is intended to benefit employees, doesn't have the opposite effect."

If you're a predator that eats baby birds -- say, an American Crow -- eavesdropping on the begging calls of nestlings can be an easy way to find your next meal. But do baby birds change their begging behavior when predators are nearby to avoid being detected and eaten? Very few studies have investigated whether nestlings react to the sounds of predators, but new research published in The Auk: Ornithological Advances shows that when their parents are away, baby Red-winged Blackbirds beg less often and stop begging sooner if they hear recordings of predators' calls.

Beloit College's Ken Yasukawa and his students used recordings of both crows and Cooper's Hawks to test the reactions of blackbird nestlings when one or both of their parents were nearby and when both parents were absent. When neither parent was around, nestlings who heard the calls of either predator adjusted their begging behavior to attract less attention. When a parent returned, however, nestlings begged noisily whether the researchers played predator recordings or not. Getting the food their parents had brought (and being noisier than their siblings in order to do so) was important enough that it outweighed the potential danger from predators.

Nest predation is so common that the researchers had trouble locating enough surviving nests to collect their data. "We spent a lot of time and effort searching for nests and then checking them daily, only to have more than half fail before the nestlings were old enough to be experimental subjects. Quite often we would go to a nest expecting to do a playback experiment, only to find that it no longer contained nestlings," says Yasukawa. "We even had one case of snake predation during our playback. We know because we had a video recording of the snake removing the nestling!"

One surprise in the study's results was that nestlings reacted to the call of Cooper's Hawks as well as crows, even though hawks are not typically nest predators, preying on adult birds instead. The researchers suspect that adaptations to avoid Cooper's Hawks predation have been so strongly favored by natural selection that they're expressed at all ages.

Human activity can alter habitats in ways that make predators more common and make it easier to find nests, so deciphering the interactions between nestlings and predators can be crucial for planning conservation efforts. "Understanding this complex system is important, because human activity has been causing bird populations to decline," says Yasukawa. "Even the very common Red-winged Blackbird has been affected by habitat conversion and destruction, as well as increases in rates of predation."

COLUMBUS, Ohio - Scientists have developed a new gene-therapy technique by transforming human cells into mass producers of tiny nano-sized particles full of genetic material that has the potential to reverse disease processes.

Though the research was intended as a proof of concept, the experimental therapy slowed tumor growth and prolonged survival in mice with gliomas, which constitute about 80 percent of malignant brain tumors in humans.

The technique takes advantage of exosomes, fluid-filled sacs that cells release as a way to communicate with other cells.

While exosomes are gaining ground as biologically friendly carriers of therapeutic materials - because there are a lot of them and they don't prompt an immune response - the trick with gene therapy is finding a way to fit those comparatively large genetic instructions inside their tiny bodies on a scale that will have a therapeutic effect.

This new method relies on patented technology that prompts donated human cells such as adult stem cells to spit out millions of exosomes that, after being collected and purified, function as nanocarriers containing a drug. When they are injected into the bloodstream, they know exactly where in the body to find their target - even if it's in the brain.

"Think of them like Christmas gifts: The gift is inside a wrapped container that is postage paid and ready to go," said senior study author L. James Lee, professor emeritus of chemical and biomolecular engineering at The Ohio State University.

And they are gifts that keep on giving, Lee noted: "This is a Mother Nature-induced therapeutic nanoparticle."

The study is published today (Dec. 16) in the journal Nature Biomedical Engineering.

In 2017, Lee and colleagues made waves with news of a regenerative medicine discovery called tissue nanotransfection (TNT). The technique uses a nanotechnology-based chip to deliver biological cargo directly into skin, an action that converts adult cells into any cell type of interest for treatment within a patient's own body.

By looking further into the mechanism behind TNT's success, scientists in Lee's lab discovered that exosomes were the secret to delivering regenerative goods to tissue far below the skin's surface.

The technology was adapted in this study into a technique first author Zhaogang Yang, a former Ohio State postdoctoral researcher now at the University of Texas Southwestern Medical Center, termed cellular nanoporation.

The scientists placed about 1 million donated cells (such as mesenchymal cells collected from human fat) on a nano-engineered silicon wafer and used an electrical stimulus to inject synthetic DNA into the donor cells. As a result of this DNA force-feeding, as Lee described it, the cells need to eject unwanted material as part of DNA transcribed messenger RNA and repair holes that have been poked in their membranes.

"They kill two birds with one stone: They fix the leakage to the cell membrane and dump the garbage out," Lee said. "The garbage bag they throw out is the exosome. What's expelled from the cell is our drug."

The electrical stimulation had a bonus effect of a thousand-fold increase of therapeutic genes in a large number of exosomes released by the cells, a sign that the technology is scalable to produce enough nanoparticles for use in humans.

Essential to any gene therapy, of course, is knowing what genes need to be delivered to fix a medical problem. For this work, the researchers chose to test the results on glioma brain tumors by delivering a gene called PTEN, a cancer-suppressor gene. Mutations of PTEN that turn off that suppression role can allow cancer cells to grow unchecked.

For Lee, founder of Ohio State's Center for Affordable Nanoengineering of Polymeric Biomedical Devices, producing the gene is the easy part. The synthetic DNA force-fed to donor cells is copied into a new molecule consisting of messenger RNA, which contains the instructions needed to produce a specific protein. Each exosome bubble containing messenger RNA is transformed into a nanoparticle ready for transport, with no blood-brain barrier to worry about.

"The advantage of this is there is no toxicity, nothing to provoke an immune response," said Lee, also a member of Ohio State's Comprehensive Cancer Center. "Exosomes go almost everywhere in the body, including passing the blood-brain barrier. Most drugs can't go to the brain.

"We don't want the exosomes to go to the wrong place. They're programmed not only to kill cancer cells, but to know where to go to find the cancer cells. You don't want to kill the good guys."

The testing in mice showed the labeled exosomes were far more likely to travel to the brain tumors and slow their growth compared to substances used as controls.

Because of exosomes' safe access to the brain, Lee said, this drug-delivery system has promise for future applications in neurological diseases such as Alzheimer's and Parkinson's disease.

"Hopefully, one day this can be used for medical needs," Lee said. "We've provided the method. If somebody knows what kind of gene combination can cure a certain disease but they need a therapy, here it is."

In first-of-its-kind research, NOAA scientists and academic partners used 100 years of microscopic shells to show that the coastal waters off California are acidifying twice as fast as the global ocean average -- with the seafood supply in the crosshairs.

California coastal waters contain some of our nation's more economically valuable fisheries, including salmon, crabs and shellfish. Yet, these fisheries are also some of the most vulnerable to the potential harmful effects of ocean acidification on marine life. That increase in acidity is caused by the ocean absorbing excess carbon dioxide from the atmosphere.

100 years and 2,000 shells later

In the new study published in the journal Nature Geoscience, scientists examined nearly 2,000 shells of microscopic animals called foraminifera by taking core samples from the seafloor off Santa Barbara and measuring how the shells of these animals have changed over a century.

Every day, the shells of dead foraminifera rain down on the ocean floor and are eventually covered by sediment. Layers of sediment containing shells form a vertical record of change. The scientists looked back through time, layer by layer, and measured changes in thickness of the shells.

"By measuring the thickness of the shells, we can provide a very accurate estimate of the ocean's acidity level when the foraminifera were alive," said lead author Emily Osborne, who used this novel technique to produce the longest record yet created of ocean acidification using directly measured marine species. She measured shells within cores that represented deposits dating back to 1895.

The fossil record also revealed an unexpected cyclical pattern: Though the waters increased their overall acidity over time, the shells revealed decade-long changes in the rise and fall of acidity. This pattern matched the Pacific Decadal Oscillation, a natural warming and cooling cycle. Human-caused carbon dioxide emissions are driving ocean acidification, but this natural variation also plays an important role in alleviating or amplifying ocean acidification.

"During the cool phases of the Pacific Decadal Oscillation, strengthened winds across the ocean drive carbon dioxide-rich waters upward toward the surface along the West Coast of the U.S.," said Osborne, a scientist with NOAA's Ocean Acidification Program. "It's like a double whammy, increasing ocean acidification in this region of the world."

Scientists hope to build on the new research to learn more about how changes in ocean acidification may be affecting other aspects of the marine ecosystem.

CAMBRIDGE, MA -- During a chemical reaction, the molecules involved in the reaction gain energy until they reach a "point of no return" known as a transition state.

Until now, no one has glimpsed this state, as it lasts for only a few femtoseconds (quadrillionths of a second). However, chemists at MIT, Argonne National Laboratory, and several other institutions have now devised a technique that allows them to determine the structure of the transition state by detailed observation of the products that result from the reaction.

"We're looking at the consequences of the event, which have encoded in them the actual structure of the transition state," says Robert Field, the Robert T. Haslam and Bradley Dewey Professor of Chemistry at MIT. "It's an indirect measurement, but it's among the most direct classes of measurement that have been possible."

Field and his colleagues used millimeter-wave spectroscopy, which can measure the rotational-vibrational energy of reaction product molecules, to determine the structure of the products of the breakdown of vinyl cyanide caused by ultraviolet light. Using this approach, they identified two different transition states for the reaction and found evidence that additional transition states may be involved.

Field is the senior author of the study, which appears this week in the Proceedings of the National Academy of Sciences. The lead author is Kirill Prozument, a former MIT postdoc who is now at Argonne National Laboratory.

A central concept of chemistry

For any chemical reaction to occur, the reacting molecules must receive an input of energy that enables the activated molecules to reach a transition state, from which the products are formed.

"The transition state is a central concept of chemistry," Field says. "Everything we think about in reactions really hinges on the structure of the transition state, which we cannot directly observe."

In a paper published in 2015, Field and his colleagues used laser spectroscopy to characterize the transition state for a different type of reaction known as an isomerization, in which a molecule undergoes a change of shape.

In their new study, the researchers explored another style of reaction, using ultraviolet laser radiation to break molecules of vinyl cyanide into acetylene and other products. Then, they used millimeter-wave spectroscopy to observe the vibrational level population distribution of the reaction products a few millionths of a second after the reaction occurred.

Using this technique, the researchers were able to determine nascent populations of molecules in different levels of vibrational energy -- a measure of how much the atoms of a molecule move relative to each other. Those vibrational energy levels also encode the geometry of the molecules when they were born at the transition state, specifically, how much bending excitation there is in the bond angles between hydrogen, carbon, and nitrogen atoms.

This also allowed the researchers to distinguish between two slightly different products of the reaction -- hydrogen cyanide (HCN), in which a central carbon atom is bound to hydrogen and nitrogen, and hydrogen isocyanide (HNC), in which nitrogen is the central atom, bound to carbon and hydrogen.

"This is the fingerprint of what the structure was during the instant that the molecule was released," Field says. "Previous methods of looking at reactions were blind to the vibrational populations, and they were blind to the difference between HCN and HNC."

The researchers found both HCN and HNC, which are produced via different transition states, among the reaction products. This suggests that both of those transition states, which represent different mechanisms of reaction, are in play when vinyl cyanide is broken apart by the ultraviolet laser.

"This implies that there are two different mechanisms competing for transition states, and we're able to separate the reaction into these different mechanisms," Field says. "This is a completely new technique, a new way of going to the heart of what happens in a chemical reaction."

Additional mechanisms

The researchers' data shows that there are additional reaction mechanisms beyond those two, but more study is needed to determine their transition state structures.

Field and Prozument are now using this technique to study the reaction products of the pyrolytic breakdown of acetone. They also hope to use it to explore how triazine, a six-membered ring of alternating carbon and nitrogen atoms, breaks down into three molecules of HCN, in particular, whether all three products form simultaneously (a "triple whammy") or sequentially.

If you disagree with someone, it might not make any difference how certain they say they are, as during disagreement your brain's sensitivity to the strength of people's beliefs is reduced, finds a study led by UCL and City, University of London.

The brain scanning study, published in Nature Neuroscience, reveals a new type of confirmation bias that can make it very difficult to alter people's opinions.

"We found that when people disagree, their brains fail to encode the quality of the other person's opinion, giving them less reason to change their mind," said the study's senior author, Professor Tali Sharot (UCL Psychology & Language Sciences).

For the study, the researchers asked 42 participants, split into pairs, to estimate house prices. They each wagered on whether the asking price would be more or less than a set amount, depending on how confident they were. Next, each lay in an MRI scanner with the two scanners divided by a glass wall. On their screens they were shown the properties again, reminded of their own judgements, then shown their partner's assessment and wagers, and finally were asked to submit a final wager.

The researchers found that, when both participants agreed, people would increase their final wagers to larger amounts, particularly if their partner had placed a high wager.

Conversely, when the partners disagreed, the opinion of the disagreeing partner had little impact on people's wagers, even if the disagreeing partner had placed a high wager.

The researchers found that one brain area, the posterior medial prefrontal cortex (pMFC), was involved in incorporating another person's beliefs into one's own. Brain activity differed depending on the strength of the partner's wager, but only when they were already in agreement. When the partners disagreed, there was no relationship between the partner's wager and brain activity in the pMFC region.

The pMFC is known to be involved in decision-making, and helps to signal when a decision should be changed.

The researchers say that the tendency to ignore the strength of opposing beliefs may generate polarisation and facilitate the maintenance of false beliefs.

First author Dr Andreas Kappes (City, University of London) said: "Our findings could help make sense of some puzzling observations in domains including science and politics."

"For instance, over the last decade climate scientists have expressed greater confidence that climate change is man-made. Yet, the percentage of the population that believe this notion to be true has dropped over the same period of time. While there are complex, multi-layered reasons for this specific trend, such examples may be related to a bias in how the strength of other's opinions are encoded in our brains."

Professor Sharot added: "Opinions of others are especially susceptible to the confirmation bias, perhaps because they are relatively easy to dismiss as subjective. Because humans make the vast majority of decisions - including professional, personal, political and purchase decisions - based on information received from others, the identified bias in using the strength of others' opinions is likely to have a profound effect on human behaviour."

Electrons with 'colleagues' - other leptons - are one of many products of collisions observed in the LHCb experiment at the Large Hadron Collider. According to theorists, some of these particles may be created in processes that extend beyond standard physics. The latest analysis verifies these predictions.

Do the anomalies observed in the LHCb experiment in the decay of B mesons hide hitherto unknown particles from outside the currently valid and well-tested Standard Model? To answer this question, physicists are looking not only for further signs of the existence of new particles, but also for traces of the phenomena that may occur with them. One of the processes proposed by theoreticians going beyond the world of known physics is the breaking of the principle of preservation of the lepton flavour. This hypothetical phenomenon was in the centre of interest of an international group of researchers, which included representatives of the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow, Technische Universität in Dortmund (TUD) and Centre National de la Recherche Scientifique (CNRS) in Paris. They paid particular attention to the analysis of data collected in 2011-12 during proton collisions as part of the LHCb experiment at the Large Hadron Collider at CERN near Geneva. Their results are discussed in the prestigious Physical Review Letters.

Thanks to decades of experiments and measurements carried out by nuclear physicists and cosmic ray researchers, it is known that particles of matter are divided into two completely independent families: quarks and leptons (with their anti-matter counterparts). Quarks (up, down, charm, strange, top and bottom) always appear in groups. Systems of two quarks are known as mesons, those made up of three quarks are baryons. The latter include protons and neutrons, the particles that make up atomic nuclei. In turn, leptons include electrons, muons, tau particles and their corresponding neutrinos.

"The properties of leptons and quarks differ fundamentally. As a result, both groups of particles are described using sets of different numbers, called quantum numbers. One of the quantum numbers used to describe leptons is the lepton number. For example, each electron has an electron number of 1. In turn, antimatter counterparts of electrons, i.e. positrons, have an electron number of -1", explains Dr. Jihyun Bhom (IFJ PAN), the main author of the analysis. "That's how we come to the key phenomenon to explain the meaning of our work. Under the Standard Model, the principle of preserving the lepton number applies. It says that the sum of lepton numbers of particles at the beginning and end of the process must always be the same".

The requirement to preserve the lepton number means that if, for example, two electrons with a total electron number of two participate in an interaction, at the end of the process this number will also be two. In the example presented, under the Standard Model it is possible to produce two electrons as well as four electrons and two positrons, and so on.

Both leptons and quarks can be divided into three groups called generations. The existence of the same number of generations of leptons and quarks prompted theorists to suppose that with sufficiently high energy, leptons and quarks could 'weld together' into leptoquarks, hypothetical particles with the characteristics of both leptons and quarks. If they existed, leptoquarks should be unstable particles with very high masses, comparable even to the mass of an entire lead nucleus.

"In processes involving leptoquarks, lepton numbers do not be preserved. The detection of traces of phenomena where the principle of preserving the lepton number was violated would therefore be a significant step on the road to the detection of particles outside the Standard Model. In particular, it would make it easier for us to interpret the nature of the anomalies that have recently been more and more clearly visible in data from the decay of B mesons, i.e. particles containing the down quark and the bottom quark", says Dr. Bhom.

In the latest statistical analyses it turned out necessary to use artificial intelligence - in addition, not just one.

"We were interested in the B meson decays leading to the formation of the K meson, a muon and an electron. However, it just so happens that under the Standard Model, a significant proportion of B meson decays lead to exactly the same products with addition of neutrinos (the latter cannot be recorded). This huge background had to be eliminated very precisely from the collected data. One artificial intelligence was responsible for this task. The second proved necessary to get rid of background residues that passed through the first", explains Dr. Bhom.

Despite the use of sophisticated mathematical tools, the researchers from IFJ PAN, TUD and CNRS failed to detect traces of phenomena breaking the preservation of the lepton number. However, every cloud has a silver lining.

"With a certainty of up to 95% we've improved the existing restrictions on the solutions presented by theoreticians to explain the presence of anomalies in the decay of B mesons by a whole order of magnitude. As a result, we are the first to have significantly narrowed the area of searching for theories explaining the existence of these anomalies using new physics", emphasizes Dr. Bhom.

If they do exist, processes that break the principle of preserving the lepton number obviously occur much less frequently than could be predicted by the most popular extensions of the Standard Model involving leptoquarks. What's more, anomalies in the decay of B mesons themselves do not have to be associated with new particles. The possibility can still not be excluded that they are artefacts of measurement techniques, the mathematical tools used or the result of not taking into account some phenomenon occurring within currently known physics. One can only hope that subsequent, already initiated analyses, taking into account the latest data collected at the LHC, will finally dispel doubts about the existence of physics beyond the Standard Model within a few years.

CHAPEL HILL, NC - December 16, 2019 - Axons are the long thread-like extensions of neurons that send electrical signals to other brain cells. Thanks to axonal connectivity, our brains and bodies can do all necessary tasks. Even before we're born, we need axons to grow in tracts throughout gray matter and connect properly as our brains develop. UNC School of Medicine researchers have now found a key reason why connectivity goes awry and leads to rare but debilitating neurodevelopmental conditions.

Published in the journal Developmental Cell, researchers led by Eva Anton, PhD, professor of cell biology and physiology at UNC-Chapel Hill, show how two gene mutations alter the function of neuronal cilia - antennae-like protuberances found on many cell types. The resulting dysfunctional cilia affect axonal connectivity and leads to rare Joubert syndrome-related disorders (JSRD).

"Our experiments demonstrate that ciliary signaling facilitates appropriate patterns of axon tract development and connectivity," said Anton, who is a member of the UNC Neuroscience Center. "Disrupting ciliary signaling can lead to axonal tract malformations in JSRD."

Although cilia are found on most cell types, their significance in brain development, has been largely underappreciated, until recently.

Scientists now know that cilia sense the environment around them, and dysfunctional cilia mess up axonal growth and connectivity during fetal development. Babies born with dysfunctional cilia and associated irregular axonal growth and connectivity can develop JSRD. Molar tooth sign, a characteristic defect of axonal projections detectable in brain MRI images, is often used to diagnose JSRD. People with the condition experience developmental delays, intellectual disabilities, abnormal respiratory rhythms, trouble controlling their body movements, and other serious health issues. But how this happens has not been clear.

Using neuron-specific mouse genetic models of two genes called Arl13b and Inpp5 and related human mutations from JSRD patients, as well as chemo-genetic and opto-genetic manipulation of primary cilia signaling, Anton and colleagues investigated how cilia become dysfunctional and affect axonal connectivity during brain development.

In mice, they found that deletion of Arl13b or Inpp5e impairs the ability of the primary cilium to function as a signaling hub, thus allowing them to examine how cilia-driven signaling regulates axon growth and connectivity in normal and JSRD brains. Anton and colleagues went on to delineate ciliary-driven changes in cell signaling, particularly the ones mediated through major signaling proteins PI3K AKT, and AC3 effectively modulate axonal behavior.

Before this research, the significance of primary cilia in the emergence of brain connectivity were undefined. Nor did the research community understand exactly how cilia dysregulation led to axonal tract defects in Joubert syndrome-related disorders.

"By shedding light on the significance of primary cilia in the emergence of brain connectivity, this research helps us understand how cilia dysregulation led to axonal tract defects in Joubert syndrome-related disorders," Anton said. "Our studies indicate precise manipulation of ciliary signaling in the future may be tested and utilized to alleviate neuronal connectivity defects in ciliopathies, such as JSRD."

Nearly three-fourths of young adults experiencing homelessness who are raped do not seek post-sexual assault medical care, missing an opportunity to greatly reduce their risk of contracting HIV, according to a survey led by The University of Texas Health Science Center at Houston (UTHealth).

Findings appeared today in the American Journal of Preventive Medicine. The survey involved 1,405 adults between 18 and 26 years of age who were experiencing homelessness.

"Steps can be taken to reduce the risk of HIV infection immediately following rape. But, this window of opportunity closes within 72 hours," said Diane Santa Maria, DrPH, RN, the study's senior author and the dean ad interim of Cizik School of Nursing at UTHealth.

Those steps involve treatment called post-exposure prophylaxis or PEP in which antiretroviral medicines are given to patients. PEP is very effective in preventing HIV when administered correctly, reports the Centers for Disease Control and Prevention.

Tragically, many rape victims are putting off medical exams for the wrong reasons.

"Many victims think you have to file a police report when you go to an emergency room but that is not the case. You can be treated for HIV and unintended pregnancy prevention and leave," said Santa Maria, holder of the Dorothy T. Nicholson Distinguished Professorship and the John P. McGovern Distinguished Professorship in Nursing at Cizik School of Nursing.

"Study participants also said they didn't think the exams were important," she said.

The way to clear up these misconceptions, according to Santa Maria, is for educators to prepare junior and senior high students at an early age should the unthinkable happen. "People need to know what to do ahead of time," she said.

In addition, Santa Maria called for more health care providers to receive sexual assault care training and for the number of sexual assault nurse examiners to be increased.

Santa Maria said she did the study because little is known about whether youth experiencing homelessness seek help after being raped. "Missing or delaying post-sexual assault care can lead to untreated sexually transmitted diseases, pregnancy, depression, and substance abuse," she said.

Houston was one of seven study sites across the country and the survey was conducted between June 2016 and July 2017. In each city, approximately 200 young adults experiencing homelessness completed a questionnaire.

The study included 337 participants who reported that they were raped. Transgender/gender-expansive youth had the highest rate of rape. Earlier onset and longer durations of homelessness were associated with higher rates of rape.

Only 98 of the 337 who reported rape received a post-sexual assault examination. Hispanic youths were most likely to get an exam while mixed race youth were the least likely.

Of those who did not get an exam, 44% reported that they did not want to involve the legal system and 35% did not think the exams were important.

Adults who had experienced dating violence, engaged in trading sex, or who had been involved in the juvenile justice system were significantly more likely to prefer not wanting to involve the legal system.

"Youth experiencing homelessness are at an elevated risk for sexual assault yet underutilize post-sexual assault health care services that greatly reduce the risk for HIV and unintended pregnancy," the authors wrote.

PULLMAN, Wash.--Casual flirting with colleagues at work is relatively harmless and can even be beneficial, new research from Washington State University shows.

The study, published in Organizational Behavior and Human Decision Processes, focuses on what the researchers describe as positively experienced social sexual behavior in the workplace, such as light-hearted flirtation and banter among peers. They draw clear distinctions between this type of interaction and the persistent, unwelcome acts of sexual harassment which are often perpetrated by those in positions of authority. Being the target of harassment creates stress, whereas WSU Assistant Professor Leah Sheppard and her colleagues found that being the recipient of flirtation can relieve it.

The study also questions whether recent zero-tolerance policies toward workplace sexual behavior are missing the mark -- policies such as the five-second stare limit reportedly in place at Netflix or NBC's ban on sharing cab rides and guidelines for coworker hugging.

"Some flirting is happening, and it seems pretty benign," said Sheppard, the first author on the paper. "Even when our study participants disliked the behavior, it still didn't reach the threshold of sexual harassment. It didn't produce higher levels of stress, so it is a very different conceptual space."

In the study, Sheppard and researchers from the U.S., Canada and the Netherlands examined the little-studied area of non-harassing social sexual behavior which includes what the researchers call sexual storytelling, such as jokes and innuendoes, as well as flirtatious behavior, comprised of coy glances and compliments on physical appearance.

The researchers analyzed a series of surveys with different sets of workers in the U.S., Canada and the Philippines. The surveys involved hundreds of participants, and responses were collected from different groups of participants both before and after the advent of the #MeToo movement, which exposed sexual harassment by prominent figures in many fields and industries.

Through these surveys, the researchers found that most employees were somewhat neutral about sexual storytelling but felt more positively about flirtation.

"What we found is that when flirtation is enjoyed, it can offer some benefits: it makes people feel good about themselves, which can then protect them from stressors in their lives," said Sheppard.

In one survey, the researchers asked workers about their experience with not only flirtation but also workplace injustice, such as when they felt their supervisors were treating them unfairly. The researchers then surveyed the workers' spouses and coworkers to get outside observations on their stress levels. They found that workplace flirtation actually helped alleviate the stress and insomnia of people dealing with workplace injustice.

The study authors argue that excessively strict policies meant to deter sexual harassment can inadvertently send the message that all forms of social sexual behavior, even potentially beneficial ones, must be monitored, controlled and punished.

The surveys revealed that while employees enjoyed flirtation when it came from coworkers, it was less appreciated from supervisors. Sheppard said these results indicate that managers should look to find a balance, avoiding overly restrictive policies on social sexual behavior without promoting or engaging in it themselves.

"Zero-tolerance rules can add awkwardness into what are pretty naturally occurring behaviors within established friendships," said Sheppard. "At the same time, we're not encouraging managers to facilitate this behavior. This is just something that probably organically happens. Managers also should be careful in engaging in flirtation themselves, especially with anyone at a lower level. As soon as there's a power imbalance, you risk entering the domain of what might be perceived as sexual harassment."

Boston, MA - Children in low- and middle-income countries (LMICs) are receiving an average of 25 antibiotic prescriptions during their first five years of life, an excessive amount that could harm the children's ability to fight pathogens as well as increase antibiotic resistance worldwide, according to a new study from the Swiss Tropical and Public Health Institute (Swiss TPH) and Harvard T.H. Chan School of Public Health.

"We knew children in LMICs are sick more often, and we knew antibiotic prescription rates are high in many countries. What we did not know was how these elements translate into actual antibiotic exposure--and the results are rather alarming," said Günther Fink, lead author of the study and head of the Household Economics and Health Systems Research unit at Swiss TPH.

The study--the first to look at total antibiotic prescribing in children under the age of five in LMICs--will be published on 13 December in The Lancet Infectious Diseases.

Global health threat

Antimicrobial resistance is one of today's biggest threats to global health and development, according to the World Health Organization. One factor contributing to this global health threat is the excessive use of antibiotics worldwide. Previous studies have shown that antibiotics are overprescribed to children in many countries. In Tanzania, for instance, several studies have shown that over 90% of children who visit a health facility receive an antibiotic, although only in about 20% of the cases treatment was actually required.

The research team from Swiss TPH and Harvard Chan School analyzed data from 2007-2017 from health facilities and household surveys from eight countries: Haiti, Kenya, Malawi, Namibia, Nepal, Senegal, Tanzania, and Uganda. The study found that, on average, children received 25 antibiotic prescriptions through age five--a "remarkable" estimate, the authors wrote, given that two antibiotic prescriptions per year is considered excessive in many high-income settings. Results showed that antibiotics were administered in 81% of cases for children with a respiratory illness, in 50% for children with diarrhea, and in 28% for children with malaria.

The researchers found that the number of antibiotic prescriptions in early childhood varied from country to country: While a child in Senegal received approximately one antibiotic prescription per year in the first five years of life, a child in Uganda was prescribed up to 12. In comparison, a prior study showed that children under five in Europe receive less than one antibiotic prescription per year on average. "This number is still high given that the vast majority of infections in this age group are of viral origin," said Valérie D'Acremont, a study co-author and head of the Management of Fevers group at Swiss TPH.

"What is unique about this study is that it provides a much more comprehensive picture of pediatric antibiotic exposure in LMICs than what has been reported previously. It combines both household data on where and when children are brought for care with data from direct observations of health care workers caring for sick children," said Jessica Cohen, the Bruce A. Beal, Robert L. Beal, and Alexander S. Beal Associate Professor of Global Health at Harvard Chan School and senior author of the study.

Impact on children

"The consequences of antibiotic overprescription not only pose a huge threat to global health, but can also result in a concrete health impact for these children," said Valérie D'Acremont. "Excess antibiotic use destroys the natural gut flora which is essential to fighting pathogens."

A Swiss TPH research project is underway to better comprehend the health impact of overusing antibiotics on children. "Understanding the concrete impact on individual children is crucial to achieve a policy change," said Fink. His research team is currently comparing policies at a country level to identify best practices that lead to lower antibiotic prescription rates.

In a recently published paper in Science Advances, Feng Ding of the Center for Multidimensional Carbon Materials, within the Institute of Basic Science (IBS, South Korea) and colleagues, have achieved the creation of a specific type of carbon nanotubes (CNTs) with a selectivity of 90%, and expanded the current theory that explains the synthesis of these promising nano-cylinders.

CNTs are incredibly strong and light nanomaterials made of carbon with superior current carrying capacity and very high thermal conductivity, making them ideal for electronic applications. Although CNTs are considered as some of the most interesting materials for the future, scientists are still struggling for their controllable synthesis.

The CNTs' shape can be compared to paper tubes: in the same way as a cylinder can be created by rolling a sheet of paper, so CNTs can be imagined as a single layer of graphite rolled up on itself. Similarly, as different tubes can be produced by rolling a paper around its long side, its short side, or diagonally at different angles. Depending on the rolling direction, a graphite layer can produce different CNT structures, some are conducting and others are semiconducting, thus selectively creating a specific type of CNT will be key for their future use, such as building energy efficient computer chips. However, CNTs are not produced by rolling, but are grown nanometer after nanometer, adding carbon at the rim of nano-cylinders, one atom at a time. Despite various studies during the last three decades, the understanding on CNT growth remains very limited and rational experimental design for the growth of specific types of CNTs is challenging.

One of the most promising manufacturing methods for CNT is the chemical vapor deposition (CVD). In this process, metal nanoparticles combined with carbon-containing gases form CNTs inside a high-temperature furnace. On the tip of the tubes, the metal nanoparticles play a critical role as catalysts: they dissociate the carbon source from the gases, and assist the attachment of these carbon atoms to the CNT wall, making the tubes longer and longer. The growth of the CNT terminates once the catalyst particle is encapsulated by graphitic or amorphous carbon.

Carbon atoms are inserted onto the interface between a growing CNT and a catalyst nanoparticle, in active sites of the rim, and are available to incorporate new atoms. A previous model of CNT's growth rate showed that the latter is proportional to the density of these active sites at the interface between CNT and the catalyst, or the specific structure of the CNT.

In this study, the researchers monitored the steady growth of CNTs on a magnesium oxide (MgO) support with carbon monoxide (CO) as the carbon feedstock and cobalt nanoparticles as catalysts at 700oC. The direct experimental measurements of 16 CNTs showed how to expand the previous theory. "It was surprising that the growth rate of a carbon nanotubes only depends on the size of the catalyst particle. This implies that our previous understanding on carbon nanotubes growth was not complete," says Maoshuai He, the first author of the paper.

More specifically, carbon atoms that are deposited on the catalyst particle surface can be either incorporated on the active side of the CNT or removed by etching agents, such as H2, H2O, O2, or CO2. To explain the new experimental observations, the team included the effects of carbon insertion and removal during CNT growth and discovered that the growth rate depends on the catalyst's surface area and tube diameter ratio.

"Compared to the previous model, we added three more factors: the rate of precursor deposition, the rate of carbon removal by etching agents, and the rate of carbon insertion into a carbon nanotube wall. When feedstock dissociation cannot be balanced by carbon etching, the rate of carbon nanotube growth will no longer depend on the structure of the carbon nanotube. On the other hand, the previous theory is still valid if the etching is dominating," explains Ding, a group leader of the Center for Multidimensional Carbon Materials.

Interestingly, the new theory of CNT growth leads to a new mechanism to selectively grow a specific type of CNTs, denoted as (2n, n) CNTs, which is characterized by the maximum number of active sites at the interface between the CNT and the catalyst. This CNT structure would correspond to rolling a sheet of graphite diagonally at an angle of around 19 degrees.

"If there is no carbon etching and the carbon nanotubes growth is slow, carbon atoms on the catalyst surface will accumulate," says Jin Zhang, co-author of the study and professor of Peking University, China. "This may lead to the formation of graphitic or amorphous carbon, which are established mechanisms of carbon nanotube growth termination. In this case, only carbon nanotubes which are able to add carbon atoms on their walls, that is with the highest number of active sites, can survive."

Guided by the new theoretical understanding, the researchers were able to design experiments that produced (2n, n) CNTs with a selectivity of up to 90%: the highest selective growth of this type of CNT was achieved in the absence of any etching agent and with a high feedstock concentration.

A Dartmouth study finds that the conscious perception of visual location occurs in the frontal lobes of the brain, rather than in the visual system in the back of the brain. The findings are published in Current Biology.

The results are significant given the ongoing debate among neuroscientists on what consciousness is and where it happens in the brain.

"Our study provides clear evidence that the visual system is not representing what we see but is representing the physical world," said lead author, Sirui Liu, a graduate student of psychological and brain sciences at Dartmouth. "What we see emerges later in the processing hierarchy, in the frontal areas of the brain that are not usually associated with visual processing."

To examine how the perception of position occurs in the brain, participants were presented with visual stimuli and asked to complete a series of behavioral tasks while in a functional magnetic resonance imaging (fMRI) scanner. For one of the tasks, participants were asked to stare at a fixed black dot on the left side of the computer screen inside the scanner while a dot that flickered between black and white, known as a Gabor patch, moved in the periphery. Participants were asked to identify the direction the patch was moving. (Click here (https://www.cavlab.net/Demos/CBDemo/) to view or download the video of the stimulus used in the experiment). The patch appears to move across the screen at a 45 degree angle, when in fact it is moving up and down in a vertical motion. Here, the perceived path is strikingly different from the actual physical path that lands on the retina. This creates a "double-drift" illusion. The direction of the drift was randomized across the trials, where it drifted either towards the left, right or remained static.

Using fMRI data and multivariate pattern analysis, a method for studying neural activation patterns, the team investigated where the perceived path, tilted left or right from vertical, appears in the brain. They wanted to determine where conscious perception emerges and how the brain codes this. On average, participants reported that the perceived motion path was different from the actual path by 45 degrees or more. The researchers found that while the visual system collects the data, the switch between coding the physical path and coding the perceived path (illusory path) takes place outside of the visual cortex all the way in the frontal areas, which are higher-order brain regions.

"Our data firmly support that frontal areas are critical to the emergence of conscious perception," explained study co-author and co-principal investigator, Patrick Cavanagh, a research professor of psychological and brain sciences at Dartmouth, and senior research fellow and adjunct professor of psychology at Glendon College. "While previous research has long established the frontal lobes are responsible for functions such as decision-making and thinking, our findings suggest that this area of the brain is also the end step for perceiving where objects are. So, that's kind of radical," he added.

How much light do you receive over the course of a day? What type of light enters your eyes? Spectrace, a new piece of wearable tech, could soon provide the answers to these questions. In a groundbreaking move, researchers at EPFL's Laboratory of Integrated Performance in Design (LIPID) have teamed up with teachers and students from Geneva School of Art and Design (HEAD - Genève) to develop a light sensor concept. The device, which rests around the neck like a pair of headphones or can be attached to an item of clothing with a magnetic pin, is designed to be worn all day long - at work, during exercise and in social settings.

The project has just been awarded an InnoSuisse grant in the eHealth category. Earlier this year, the project received support through an Explorer Grant from the ENAC InnoSeed program at EPFL. This new funding will be used to develop a modular, working prototype and test it in real-world conditions by 2021, with the aim of founding a spin-off to bring the Spectrace sensor to the wider scientific community and the general public.

Circadian rhythms

Since the discovery of melanopsin 20 years ago, scientists have taken a growing interest in how a shortage of natural light and excessive exposure to artificial light from screens affect our bodies. Melanopsin, a blue-light-sensitive photopigment found in the human eye, helps keep the body's internal clock on track and tells our brain whether it's day or night. It is responsible for synchronizing all our circadian rhythms, and this has a significant impact on our health, from regulating our sleep and our hormone cycle - including the production of melatonin at night - to the ability of our immune system to function properly.

"We urgently need to pay more attention to our 'light hygiene'," says Professor Marilyne Andersen, the director of LIPID and an expert in the field for some 15 years. "We spend so long indoors, which means we're suffering from a chronic shortage of daylight, and staring at screens all the time, which has especially negative effects at night. We should in fact be getting plentiful light that is rich in blue wavelengths during the day, in order to accumulate a sufficient amount, as this will make us feel better, and limiting this exposure well before bedtime."

Gap to fill

Various types of wearable light sensors exist on the market. Yet none of them can truly measure our exposure to the spectral range of light, i.e., as a function of the light's wavelength (all the constituent "colors"). That's what's new about the prototype developed by EPFL. There is currently not enough data on the type of light to which we are actually exposed as a result of our daily activities and the environment in which we live and work. The physiological effects of light depend not only on its intensity and how long we're exposed to it, but its spectrum as well. That's the gap that the new Spectrace sensor is meant to fill.

Forrest Webler, as part of his PhD research at LIPID, which is being jointly supervised by Prof. Andersen and Dr. Manuel Spitschan at the University of Oxford's Department of Experimental Psychology, is working on the concept of the "spectral diet" in order to develop a light exposure classification system.

Webler's first step was to source a miniature spectrometer designed for the food processing industry by South Korean startup nanoLambda. Teaming up with Giorgia Chinazzo, then a postdoctoral researcher at LIPID who was involved in this project from the start, he then brought in some EPFL electronics students to repurpose the spectrometer, turning it into a wearable device - with a built-in UV sensor and photometer - that offers a time resolution of less than a second.

Collaboration with HEAD - Genève

At the same time, EPFL worked with Product and Media/interaction designers from HEAD - Genève at a workshop in July 2019, with close to ten students and alumni, that was led by Laure Krayenbuhl, the founder of Biel-based a-project studio. Their mission was to come up with an attractive design that people would be happy to wear. After exploring a variety of concepts, from over-ear and lapel-pin designs to biomaterial patches, they eventually settled on a smart collar-style device with alternative pin attachment systems. The development process intensified this past fall, with the design and technical aspects influencing each other and evolving synergistically.

Is the spectral profile of people who bike, drive and take the metro to work so different that it affects their health and well-being? Do office window size and orientation matter? Researchers at LIPID will be tackling these questions and more in the coming years.

WASHINGTON, D.C., December 12, 2019 -- Offshore wind power generation has become an increasingly promising source of renewable energy. Much about the aerodynamic effects of larger wind farms, however, remains poorly understood. New work in this week's Journal of Renewable and Sustainably Energy, from AIP Publishing, looks to provide more insight in how the structures necessary for wind farms affect air flow.

Scientists from Cranfield University and the University of Oxford present a theoretical model for estimating the aerodynamic effects of wind turbine towers on the performance of wind farms. Using what is called a two-scale coupled momentum balance method, the group was able to theoretically and computationally reconstruct conditions that large wind farms might face in the future, including the dampening effect that comes with spacing turbines close to one another.

A key feature of the paper, said author Lun Ma, is that this most recent update to their model looks beyond a wind turbine's rotor.

"In this paper, we have newly taken into account the influence of wind turbine towers that act as support structures, which was ignored in the original two-scale momentum model," Ma said. "Therefore, essentially, the new model helps us understand the potential impact of wind turbine support structures on the wind farm blockage effect."

Even expansive offshore wind farms face a blockage effect, in which wind slows down as it approaches turbines, as well as a wake effect, in which turbines slow wind down as it passes by them.

Precisely predicting such features of a wind farm before constructing it, however, remains a major challenge for the industry.

To get at this question, the researchers turned to two-scale momentum modeling that simulates how the efficiencies of individual wind turbines decrease as more are spaced closely together within a wind farm when considered in an ideal, infinitely large wind farm.

"This efficiency reduction predicted by the two-scale momentum model is closely related to the wind farm blockage effect," Ma said. "However, the original two-scale momentum model was a highly simplified model and needed further improvements for practical applications."

The group combined the momentum balance equation with another approach, called actuator disc theory, which let them include other factors, such as the impact of turbine support structures. The approach allowed them to begin considering more practical scenarios, like wind farms that are a finite size.

They then conducted simulations using computational fluid dynamics to verify that such structures contribute to the blockage effect, particularly through the drag on the wind that they produce.

Ma said the group will look to better understand how the blockage effect changes with weather conditions.