Culture

A team of researchers led by a member of the Colorado School of Public Health faculty at the Anschutz Medical Campus examined what type of social interaction is required for people to display physiological synchrony--mutual changes in autonomic nervous system activity. The study also looked at whether the levels of autonomic arousal people share predicts affiliation and friendship interest between people.

The findings are published in Nature Scientific Reports.

"In a variety of situations, people appear more social with one another when their autonomic nervous systems are in sync. However, this is the first study to show that, although people display physiological synchrony across social contexts, how much arousal people share can vary, differentially impacting social outcomes like perceived similarity and friendship interest," said Chad Danyluck, PhD, postdoctoral fellow at the Colorado School of Public Health.

Danyluck adds, "Physiological synchrony has been found in a variety of relationships and environments, from married couples arguing to military units and sports teams coordinating their behaviors. Understanding whether and how shared arousal brings people together may help us hone the development of programs targeting team leadership and social cohesion in work environments. I am particularly interested in the role of physiological synchrony in fostering friendship interest across ethnic and racial divides."

Consistent with prior work, this study observed physiological synchrony in both branches of the autonomic nervous system and across cooperative and competitive social contexts. The authors general interest in physiological synchrony is in how synchrony during social interactions relates to social processes that ultimately lead to friendship.

The study found that different social contexts caused different levels of physiological arousal, meaning that the branches of the autonomic nervous system became either more or less reactive in response to the experimental task. However, in every condition, strangers quickly went "in sync" and did so in each branch of the autonomic nervous system whether they were high or low in arousal. Whether the social or physiological context of synchrony contributed to social outcomes, however, depended on which branch of the autonomic nervous system displayed synchrony.

The findings show that sharing similar amounts of sympathetic arousal was sufficient to increase perceptions of similarity--a precursor to friendship--regardless of social context and no matter the arousal levels partners shared. One possible explanation for this finding is that patterns of sympathetic arousal may correlate with observable body movements (and by extension a lack of arousal may correlate with a lack of body movement) that might predict perceived similarity if shared among partners. By comparison, people for whom parasympathetic synchrony and parasympathetic reactivity was high generally reported more friendship interest when the social context permitted conversation than when it did not. In other words, when parasympathetic activity increased during a social interaction, parasympathetic synchrony only mattered for the development of friendship between strangers who could converse.

Using data from 134 strangers interacting in pairs, the researchers manipulated two features of social context to test their impact on synchrony in sympathetic and parasympathetic reactivity. Participants completed a knot-tying task within a collective reward ("cooperation") or individual reward ("competition") framework while conversing or not ("talking" condition). Autonomic reactivity varied by features of social context. Synchrony occurred across social contexts in both autonomic branches. The researchers then examined how synchrony predicted affiliation.

Neuroscientists at the RIKEN Center for Brain Science (CBS) and University College London have found an anatomical link between cognitive and perceptual symptoms in autism. Published in the Journal of Neuroscience, the study identified a posterior region of the brain whose size--amount of gray matter--is related to both cognitive rigidity and overly stable visual perception, two symptoms of autism that until now were only conceptually related.

Mental inflexibility is a hallmark symptom of autism spectrum disorder (ASD). This is best seen in restricted and repetitive behaviors, which are required for an ASD diagnosis. These behaviors can range from stereotyped and repetitive movements to repetitive thoughts. Perception in people with ASD can also be less flexible than in others. This can be understood by considering a line drawing of a transparent cube (called a Necker cube, see Figure). When looking at this drawing, the 3-D structure of the cube seems to spontaneously invert; the front becomes the back and then becomes the front again. This type of perceptual switching is called "bistable" perception. In the case of autism however, perception is often overly stable, and does not switch back and forth as often as it does in others.

The team of researchers sought to find a physical neuroanatomical link between these two characteristics of autism. They recruited people with and without ASD to perform two simple computer-based tests and an MRI scan. The first computer test assessed perceptual stability. Participants viewed a bistable image in which the front and back of a cylindrical shape switch back and forth. The second test evaluated cognitive rigidity, and was designed specifically for this study. Participants were shown shapes on a display and asked to choose a rule to follow: select the brightest shape or a specific shape. The researchers counted the numbers of times each participant reported a switch in perception during the first test and the number of times they spontaneously switched rules in the second test. These measures allowed the researchers to quantify perceptual stability and cognitive rigidity for each participant.

As expected, they found that perception of the bistable image switched much less frequently in people with ASD than in the control participants. They also found that people with ASD repeated the same rule choice--brightness or shape--for longer periods of time before switching rules. A control switching test in which participants were told to switch rules did not differ between groups, meaning that switching rules was not difficult for those with ASD, but that when acting freely, they chose to switch less often than the other participants.

The results from the rule-switching task were particularly encouraging. As first author Takamitsu Watanabe from RIKEN CBS explains, "cognitive rigidity in high-functioning autism is known to be difficult to detect and quantify in conventional psychological paradigms. Here, we overcame this issue with a new spontaneous task-switching test." With these results, the team was confident that their tests were good measures of perceptual stability and cognitive rigidity.

The team then took these individual scores and tested whether they correlated with the brain anatomy seen on the MRI scans. They found that one part of the brain in particular was related to both perceptual stability and cognitive rigidity. Lower density of neurons in the posterior superior parietal lobule was associated with both less frequent perceptual switching and less frequent rule switching, and was also associated with the severity of the participant's restricted and repetitive behaviors.

"We think that the posterior superior parietal lobule is the neural basis for both overly stable perception and cognitive inflexibility, two seemingly different symptoms in autism," says Watanabe. "Knowing the importance of this brain region, we can now work to identify how it produces its effects and test whether manipulating its neural activity can mitigate these ASD symptoms."

CORVALLIS, Ore. - New strategies for river management are needed to maintain water supplies and avoid big crashes in populations of aquatic life, researchers argue in a perspective piece published today in Nature.

The scientists say a fresh approach is necessary as the climate warms, which has led to historic die-offs like the January 2019 event in the Murray-Darling Basin of Australia that saw severe water shortages bring hardship to residents and kill millions of fish.

"The world's rivers are facing tough times," said the editorial's lead author, Jonathan Tonkin, who just completed a post-doctoral appointment in Oregon State University's College of Science. "Iconic species like the Murray cod, the largest freshwater fish in Australia, are in danger of vanishing. In a 2018 heat wave in Germany and Switzerland, thousands of fish died. The multiyear drought in California has restricted water supplies and wreaked havoc on wetlands, riparian forests, fish and other aquatic life."

Tonkin and his co-authors outline a four-part plan for an "adaptive" approach to river management - moving beyond simply monitoring ecosystems to understanding the biological mechanisms at play.

"We need to develop forecasting tools that project how key species, life stages and ecosystems respond to environmental changes," said co-author David Lytle, professor of integrative biology in the OSU College of Science. "We can't just track things like species diversity and population abundance and compare them to historical averages - often by the time negative trends are detected, it's too late to turn them around."

The answer, the authors assert, is developing "process-based" models that can track and predict how ecosystems change when conditions - like smaller river flows - change. The models can be tailored to life stages of populations, whole communities of species and sequences of events, enabling tipping points to be identified.

"For example, a drier future with fewer and smaller floods has been projected to reorganize and simplify the interactions between riparian plant species in the dryland river systems of the American Southwest," said Tonkin, now at the University of Canterbury in New Zealand. "The projected changes could reduce communities' resistance to climate change and ability to ward off invasions by non-native species. Knowing that, managers can intervene before a problem takes hold."

Building effective models entails a long-term funding commitment to gather more data on the basic biology of riverine species, which means years of field monitoring. Until the data store is built up, keeping the models more simple, and finding ways to make connections across gaps in data, might help.

"Species with similar life histories or characteristics possibly respond in similar ways to changing river conditions, so it's possible that studies of one species could inform models and management elsewhere," Tonkin said.

But ultimately the construction of the best models requires more information, which is why the authors argue that data collection is the top next step for river scientists and managers.

The other three steps are:

Describe key processes in models. Scientists need to better articulate the relationships between ecosystem attributes and water flow patterns.

Focus management on bottlenecks. Intervene in ways that keep populations from crashing during extreme flows while focusing on the most vulnerable life stages, not just population abundance.

Be clear about uncertainties. Quantify the level of trust that can be placed in models' predictions, and update models regularly as new data become available.

"Freshwater biodiversity is disappearing," Tonkin said. "Climate change is magnifying the pressures on river ecosystems brought on by urbanization, invasive species and pollution. As the crisis worsens, we need to change how we study, model and manage rivers to safeguard the services they provide to humanity and all of the planet."

A multicentric translational research study carried out by groups of the Bellvitge Biomedical Research Institute (IDIBELL), Sant Joan de Déu Hospital (HSJD) , the University of Barcelona (UB), Hospital Clínic (IDIBAPS), the University of Vic (UVic), Sant Pau i la Santa Creu Hospital (IIB Sant Pau), the Rare Diseases Networking Biomedical Research Centre (CIBERER) and the Commissariat à l'Énergie Atomique (CEA, France), has demonstrated the potential of the amino acid L-serine - administered as a dietary supplement - to improve the neuronal function of a patient with a mutation of glutamate receptors associated with atypical Rett syndrome with severe encephalopathy. This collaborative study, led by Dr Xavier Altafaj ('Neuropharmacology and pain group', IDIBELL), and published in Science Signaling, opens a new range of therapeutic options for patients with mutations that affect glutamathemic neurotransmission.

Patients with atypical Rett syndrome show altered neuronal, motor, cognitive and social development. The patient who has been the object of this study presents a mutation in the GRIN2B gene, which codes for a subunit of NMDA glutamate receptors of the NMDA type called GluN2B. "Our research group specializes in the study of these receptors, which in physiological conditions are associated with learning processes, memory, neurodevelopment and neuronal plasticity, and which are the main actors in excitatory transmission and neuronal function", explains Dr Altafaj.

The HSJD medical team and the research group of Dr Altafaj initiated the study determining the impact of this GRIN2B mutation in the clinical manifestations of the patient. In order to find it out, they surrounded themselves with experts in the field of structural chemistry (Dr Olivella, UVic) and biophysics (Dr Soto, UB). The multidisciplinary study determined that the simple change of a single amino acid (deriving from the GRIN2B mutation) caused a drastic reduction in the functionality of NMDA receptors. With these results, Dr Altafaj's team began a second phase of cellular, physiological and biochemical studies with the participation of Dr Carles Sindreu (UB), which allowed them to identify a set of neuronal alterations derived from the hypofunctionality of the mutated receptors.

"In light of these experimental evidence, we proposed a very simple line of reasoning, which has become successful", Dr Altafaj explains. "Since the mutation of the receptors leads to less activity, it is necessary to recruit them in a more sustained way. If we imagine a glutamate receptor like a door that opens to allow calcium (a necessary element for neuronal function) in, the GRIN2B mutation causes this door to not open sufficiently. Therefore, if we can increase the frequency with which this door opens, we will, in this way, compensate for the defect. And this is how we evaluated the effect of D-serine (a co-agonist of these receptors, which promotes their opening), which reversed part of the alterations caused by the GRIN2B mutation."

The administration of D-serine has shown some toxicity in rodents, but its stereoisomer L-serine is a natural amino acid that is found in several foods. Chronic supplementation of L-serine powder in the patient's diet (which results in an increase in D-serine levels) led to a remarkable improvement in the patient's motor and communicative abilities. This pilot study was received with enormous interest from families with children who present mutations of the GRIN genes ("GRINpaties"), and the initiative coordinated by Dr Altafaj has recruited10% of patients with GRINpaties worldwide. Combining functional studies and the evaluation of new therapeutic complementary strategies, the Dr Altafaj's team supports families and the European clinical community, also raising awareness for this rare neuropediatic diseases.

A promising treatment with no side effects

Indeed, the evolution of the patient, who was treated by Dr Àngels Garcia Cazorla and Dr Anna López (HSJD), showed that dietary supplementation with L-serine is associated with significant improvements in the patient's symptoms, both motor and cognitive. "The patient is able to carry out basic motor tasks that were unthinkable of at the beginning of the treatment, 17 months ago. We could say that the patient is connected to the outside world that surrounds him and that represents a critical and key step towards establishing new neuronal connections", describes Dr Altafaj describes.

The researchers are cautious but at the same time optimistic: "the results that we observe in the patient after a year and a half are very promising and we hope they will continue improving, but we must also bear in mind that they are the result of a combined effort of several therapeutic interventions carried out by the family and other multidisciplinary teams. However, previous experiences with similar clinical cases had not shown such significant improvements, and in this sense this study makes us be very optimistic and pushes us forward in this direction". Because of that, a current pilot study has been joined by several European children with GRINpaties linked to the hypofunctionality of the NMDA receptors, and a multicentre clinical trial is being organized at European level.

Even though it has been led by IDIBELL, the study has been extremely collaborative and multicentric, including doctors and researchers from the HSJD, researchers from the UB, UVic, the IIB Sant Pau, the IDIBAPS, and the CIBERER: all in all, it shows "a great understanding between Catalan biomedical institutions, and above all, a strong commitment of all participants, who joined in order to improve the quality of life of the patient", Dr Altafaj says. The results of this project, who was spontaneously initiated without funding, have laid the foundations for a new project funded nationwide, and which is also supported by multiple donations that allow researchers to continue advancing in the study of these mutations and the neurological diseases they cause.

Sea otters have low genetic diversity, which could endanger their health as a species, a UCLA-led team of life scientists has discovered. The findings have implications for the conservation of rare and endangered species, in which low genetic diversity could increase the odds of extinction.

Genetic diversity is a measure of how many differences exist across the genome among individuals in a population. Large populations tend to have high genetic diversity (many differences among individuals), while small populations lose much of this diversity, resulting in individuals that are more genetically similar to one another.

The sea otter's low level of genetic diversity is similar to endangered species, such as the cheetah and Tasmanian devil, said lead author Annabel Beichman, a UCLA graduate student in ecology and evolutionary biology. She and her colleagues reconstructed the otter's evolutionary history and assessed its level of genetic diversity, history of changes in its population size, and levels of potentially harmful genetic variation.

The biologists found evidence of potentially harmful genetic variation and of mating between closely related ancestors in the sea otter genome -- a pattern that is common in endangered species with small population sizes. The team analyzed the genome of Gidget, a female sea otter from the Monterey Bay Aquarium who died this year, as well as the genome of a South American giant otter as an evolutionary point of comparison. There are 13 species of otters, and the sea otter and giant otter live in starkly different environments -- the giant otter in a warm freshwater environment and the sea otter in the frigid coastal waters of the North Pacific Ocean. This study is the first comprehensive genomic analysis of otters.

"While low diversity isn't necessarily dangerous by itself, we also found elevated levels of potentially harmful variation within genes, possibly due to a history of population declines -- which could impact the population going forward," Beichman said.

"Sea otters may be at risk," said co-senior author Robert Wayne, a UCLA distinguished professor of ecology and evolutionary biology and a Howard Hughes Medical Institute professor. "This is a warning sign, a red flag. We should make sure to not let their population decline again."

The team reported its findings June 18 in the journal Molecular Biology and Evolution.

Beichman compares the sea otter's low genetic diversity to a jar of multicolored marbles that has lost many of its colors. "Having a large amount of diversity in the population, a lot of different colors of marbles, may be helpful if a disease arises or the environment changes -- maybe green marbles are resistant to the disease, but blue and red are susceptible. But if you've lost all your green marbles by chance when the population declined, you may be stuck with only blue and red -- and not able to resist the disease," she said. "More variety gives you more shots at survival."

While seals and sea lions have lived in the ocean for 30 million years, and whales and dolphins for more than 50 million years, sea otters have had only about 5 million years to adapt to their marine environment. "In evolutionary time," Beichman said, "that's a snap of the fingers."

Whales, seals, sea lions and dolphins have a blubbery layer of fat to keep them warm in their environment of cold saltwater, but sea otters lack that layer. Instead, they have dense and water-repellant fur. Sea otters were hunted since the mid-1700s for their fur, almost to extinction. They numbered from 150,000 to 300,000 worldwide before the fur trade. Since the end of the fur trade, sea otter numbers are believed to be down to 1,000 to 2,000 worldwide.

Only about 50 southern sea otters survived in California in the early 20th century, down from 16,000 to 20,000 in the early 1700s, Wayne said. Now there are about 3,000 otters in California and sea otters are protected as a threatened species under the Endangered Species Act. Some sea otter populations went extinct, including those in Oregon and British Columbia.

"Sea otter populations crashed and we wanted to study the effects that had on its genome, as well as the effects of its marine environment on its genome," said co-senior author Kirk Lohmueller, UCLA associate professor of ecology and evolutionary biology, and of human genetics.

The biologists found evidence of small changes in a set of nine genes that cumulatively are implicated in the evolution of the thick fur of the otters. The researchers are the first to identify these genes as important in otter evolution. The team also reported on 18 significant genes that may be related to such areas as reproduction, immune function, brain development and limb development. These genes are present across mammal species, but sea otters seem to have changes in these genes that may have benefitted them during their evolution, the researchers concluded.

Beichman, Wayne, Lohmueller and colleagues are currently conducting a follow-up study to sequence the 20,000 genes in 130 other sea otters from populations around the north Pacific Rim, including the Kuril Islands north of Japan, the Aleutian Islands, central Alaska and Baja California, Mexico.

The research was funded by the National Science Foundation, the Monterey Bay Aquarium, a National Institutes of Health Training Grant in genomic analysis and interpretation, UCLA's Academic Senate and the UCLA Catalyst Program.

The complete list of co-authors may be found in the journal article.

Lake Superior island wolves are close to extinction

Despite their low genetic diversity, sea otters are fairly healthy and do not show obvious deformities. The same cannot be said for gray wolves on Isle Royale, a biosphere reserve and part of a national park on Lake Superior in Michigan. These wolves have severe health problems, such as spinal deformities and reproductive failure, and "intense inbreeding" is driving them to extinction, Wayne said.

In the late 1940s, a few wolves walked across ice to Isle Royale, where they faced no competitors and found many moose to hunt. In the following 30 years, the population of wolves on the island grew to as many as 50, and they were carefully studied. Beginning in the 1980s, their numbers began to decline, Wayne said. By 2018, the population had dwindled to a single pair of old wolves that were not reproducing and that are simultaneously father-daughter as well as half siblings.

Wayne, Lohmueller, Jacqueline Robinson (who conducted research as a UCLA graduate student in Wayne's laboratory and is now a postdoctoral scholar at UC San Francisco) and colleagues published new findings about Isle Royale wolves in the journal Science Advances on May 29. They studied the DNA of 11 gray wolves on Isle Royale between 1988 and 2012, examined skeletal remains of the island's wolves, conducted computational simulations and compared the DNA of these wolves with genetic data from wolves in Minnesota.

"We found that Isle Royale wolf genomes harbor characteristic signatures of recent inbreeding, causing large tracts of the genome to be devoid of genetic diversity," said Robinson, lead author of the study. "Our results provide guidance for the conservation of biodiversity in the increasingly fragmented landscapes of the modern world."

What are the global lessons to be learned about an endangered species?

"You have to monitor the population and make sure it's not becoming too inbred," Wayne said. "If it has become inbred, you have to consider bringing in individuals from the outside, after first knowing their genome from a blood sample to make sure they will add to the genetic diversity. This is rarely done."

New York, NY (June 18, 2019) -- A collaboration involving the Icahn School of Medicine at Mount Sinai, the German Heart Center Munich, AstraZeneca, and Karolinska Institutet in Sweden has demonstrated that more than 30 percent of heart disease risk stems from genetic factors, much more than was previously understood. The study findings, published today in the Journal of the American College of Cardiology, introduce the biology of gene networks as a means to better understand the heritability and genetic underpinnings of heart disease.

Coronary artery disease (CAD), the most common type of heart disease and one of the leading causes of death worldwide, forms plaque in the walls of the arteries that supply blood to the heart. A complete blockage of these arteries can lead to a heart attack or stroke.

Before this study, more than a decade of genome-wide-association studies (GWAS)--the analysis of genetic risk codes found more frequently in people with a particular trait, such as heart disease--had indicated that less than a quarter of CAD was considered inheritable. Meanwhile, the heritability contribution (if any) of genetic variants in gene regulatory networks (GRNs)--a set of genes that interact with each other to control a particular cell function--was unknown. In light of this, researchers used tissue data from two separate studies of individuals with CAD to determine whether genetic variants that regulate RGNs make independent contributions to the risk of heart disease.

Across vascular and metabolic tissue data, researchers identified and replicated 28 independent RGNs active in CAD and determined that the genetic variation in these networks contributed to the inherited risk of the heart disease by an additional 11 percent--adding to the 22 percent attributable risk previously identified by GWAS. This newfound contribution boosts the heritability of CAD to approximately 32 percent, spotlighting the important role played by interactions between internal environments and genetic variants--mediated by regulatory networks--in the development of heart disease.

"The results of this study demonstrate that the risk of heart disease is a concerted result of interactions between genetic variants and biological environments," said Johan LM Björkegren, Professor of Medicine (Cardiology), and Genetics, at the Icahn School of Medicine at Mount Sinai. "By understanding the complex relationship between the two, we've created a framework for identifying new risk genes in disease-relevant tissues leading to heart disease, which in turn will allow for more effective risk prediction, clinical intervention, and eventually, opportunities for novel and more effective therapies."

Another researcher involved in the study, Heribert Schunkert, MD, Professor of Cardiology at the German Heart Center in Munich, added, "A mystery of recent research was the fact that many genes contributing to the genetics of coronary artery disease affect mechanisms that were not expected in this context. The present study leads to a much better understanding of how these genes work together in precipitating or preventing the disease."

Li-Ming Gan, Vice President of Early Clinical Development, Cardiovascular, Renal and Metabolism, R&D BioPharmaceuticals, AstraZeneca, commented that this study "provides new insight into the heritability of coronary artery disease, adding a substantial number of genetic variants contributing to its heritability. Further analysis may help explain the disease's etiology and give novel insights on how to prevent its development."

A wearable non-invasive device based on near-infrared spectroscopy (NIRS) can be used to investigate blood volume and oxygenation patterns in freely diving marine mammals, according to a study publishing June 18 in the open-access journal PLOS Biology by J. Chris McKnight of the University of St. Andrews, and colleagues. The results provide new insights into how voluntarily diving seals distribute blood and manage the oxygen supply to their brains and blubber, yielding important information about the basic physiological patterns associated with diving.

In response to submersion in water, mammals show a suite of cardiovascular responses such as reduced heart rate and constriction of peripheral blood vessels. But investigating dive-by-dive blood distribution and oxygenation in marine mammals has up to now been limited by a lack of non-invasive technology that can be used in freely diving animals.

The authors hypothesized that NIRS could address this gap in knowledge by providing high-resolution relative measures of oxygenated and deoxygenated hemoglobin within specific tissues, which can in turn be used to estimate changes in blood volume. In the new study, McKnight and colleagues adapted NIRS technology for use on freely diving harbor seals to investigate blood volume and oxygenation patterns specifically in the brain and blubber, using a device that they dub the PortaSeal.

The authors used the PortaSeal to obtain detailed continuous NIRS data from four seals swimming freely in a quasi-natural foraging habitat. The device is superglued to the animals' fur; either on their heads to measure cerebral blood, or on the shoulder to monitor peripheral circulation; it is then easily removed, and the data downloaded.

Intriguingly, the results showed that seals routinely constrict their peripheral blood vessels, accompanied by increased cerebral blood volume, approximately 15 seconds before submersion. These anticipatory adjustments suggest that blood redistribution in seals is under some degree of cognitive control and is not just a reflex response to submersion. Seals also routinely increase cerebral oxygenation at a consistent time during each dive, despite a lack of access to air.

The authors propose that the ability to track blood volume and oxygenation in different tissues using NIRS will enable a more accurate understanding of physiological plasticity in diving animals in what is an increasingly disturbed and exploited environment.

"Discovering that seals, which are physiologically fascinating animals, can seemingly actively exert control over their circulatory systems is really exciting," Said Dr McKnight. "It gives a new perspective on the capacity to control the body's fundamental physiological responses. Getting this insight with non-invasive wearable technology from the bio-medical field offers many exciting future research avenues. We can start to study organs, like the brain, of seals in the open ocean performing exceptional feats like diving to 2000m for 2hrs with heart rates as low as 2bpm, and yet somehow avoid brain trauma."

An international research team led by the University of Göttingen has discovered two new Earth-like planets near one of our closest neighboring stars. "Teegarden's star" is only about 12.5 light years away from Earth and is one of the smallest known stars. It is only about 2,700 °C warm and about ten times lighter than the Sun. Although it is so close to us, the star wasn't discovered until 2003. The scientists observed the star for about three years. The results were published in the journal Astronomy and Astrophysics.

Their data clearly show the existence of two planets. "The two planets resemble the inner planets of our solar system," explains lead author Mathias Zechmeister of the Institute for Astrophysics at the University of Göttingen. "They are only slightly heavier than Earth and are located in the so-called habitable zone, where water can be present in liquid form."

The astronomers suspect that the two planets could be part of a larger system. "Many stars are apparently surrounded by systems with several planets," explains co-author Professor Stefan Dreizler of the University of Göttingen. Teegarden's star is the smallest star where researchers have so far been able to measure the weight of a planet directly. "This is a great success for the Carmenes project, which was specifically designed to search for planets around the lightest stars," says Professor Ansgar Reiners of the University of Göttingen, one of the scientific directors of the project.

Although planetary systems around similar stars are known, they have always been detected using the "transit method" - the planets have to pass visibly in front of the star and darken it for a moment, which only happens in a very small fraction of all planetary systems. Such transits have not yet been found for the new planets. But the system is located at a special place in the sky: from Teegarden's star you can see the planets of the solar system passing in front of the Sun.

"An inhabitant of the new planets would therefore have the opportunity to view the Earth using the transit method," says Reiners. The new planets are the tenth and eleventh discovered by the team.

Researchers at Baylor College of Medicine previously found evidence that the placenta harbors a sparse but still present community of microorganisms, which they and other researchers speculate may contribute to key functions in pregnancy, including immunity.

"There has been some debate about our and others' findings in the placenta. Because it is a sparse, or low biomass, community, it is a fair question to ask how much of what we identify as the microbiome is actually bacteria and how much is potentially environmental contamination, or maternal blood in the placenta," said senior author Dr. Kjersti Aagaard, professor and the Henry and Emma Meyer Chair of obstetrics and gynecology at Baylor.

Visual confirmation

"Previously, bacteria were found using metagenomics or microbiome sequencing, and now we have confirmed that signal based on our ability to label the bacterial RNA with a florescent 'tag' and actually see them," said Dr. Maxim Seferovic, instructor in obstetrics and gynecology at Baylor and lead author in the study. "We leveraged a powerful new imaging technology to add greater specificity in the signal of bacterial RNA, which helped us to see bacteria within the microarchitecture of the placental tissue."

Researchers examined microbes in term and preterm gestations using a signal amplified 16S universal in situ hybridization probe designed for bacterial rRNA, along with several other histologic methods. Seferovic said the study was carefully designed to control for contamination as best as possible, so that these sparse bacteria could be accurately attributed to their location in the placenta.

"We did not see quantitative or numerical differences between preterm or full-term births, nor did we see them localizing to different substrata. But we do see differences in what genera of bacteria are there in preterm or full term, and this supported our and other's past findings as well," said Aagaard.

A sparse community

Seferovic said the study was designed to determine if past studies were in fact accurate and truly did look at a low biomass community of microbes that could be reliably distinguished from environmental contamination. This work, when combined with that of several other labs, should give researchers confidence that not only can they sequence these microbes but also that they can see the bacteria in very predictable locations in different placentas.

Seferovic and Aagaard suggest that this boosts their team's and others' confidence that they can begin to look more toward the role of microbes in the intrauterine environment in shaping the developing immune system in the fetus, and what role things like the mom's diet or preterm birth may play in that development.

"At some point we all acquire trillions of bacteria in our bodies that we do not reject with an immune inflammatory response. We are speculating that these low biomass communities may play a key role in shaping the developing fetal immune system to help educate it on which microbes may be beneficial and which might not," Aagaard said.

Both Aagaard and Seferovic agree that there is still a lot of work ahead to be done in this exciting area of the developing microbiome and microbiome science. It is their hope that the techniques and tools developed for this study will lend a hand to other researchers similarly working in challenging low biomass communities.

PHILADELPHIA - College affirmative action bans may adversely affect the health of underrepresented minority high school students, according to the results of a new study from researchers at Penn Medicine. Between 1996 and 2013, nine U.S. states banned consideration of race and ethnicity in college admissions. A new study in PLOS Medicine shows that the action bans had unanticipated effects, specifically resulting in increased rates of smoking among minority high school students. The researchers also found evidence to suggest these effects could persist, as these students were also more likely to smoke into young adulthood compared to those who lived in states where an affirmative action ban was not enacted.

"We know that affirmative action bans reduce the likelihood of underrepresented high school students being admitted to selective colleges," said lead author Atheendar Venkataramani, MD, PhD, an assistant professor of Medicine and Medical Ethics and Health Policy at in the Perelman School of Medicine at the University of Pennsylvania. "What this study shows us is that reducing their chances to attend a top college - and potentially undermining their expectations of upward mobility, more generally - may also increase their risk of engaging in unhealthy behaviors, such as smoking or excessive alcohol use."

The researchers analyzed data from the 1991-2015 U.S. National Youth Risk Behavior Survey to investigate health risk behaviors (tobacco and alcohol use) that persisted for more than 30 days among underrepresented minority teenagers, including those who self-reported their race as "Black" or who self-reported their ethnicity as "Hispanic" or "Native American." The researchers compared changes in self-reported cigarette and alcohol use among over 35,000 students residing in states enacting bans versus those residing in states without bans. Currently, Arizona, California, Florida, Michigan, Nebraska, New Hampshire, Oklahoma, and Texas have bans on race-based affirmative action in college admissions.

Overall, self-reported rates of smoking among underrepresented minority 11th and 12th graders increased by 3.8 percentage points in the same years each of the states discussed, passed, and implemented the bans, compared to those living in states with no bans. Though the findings were not statistically significant, the researchers also found apparent increases among underrepresented minority students in rates of alcohol use (5.9 percent), and binge drinking (3.5 percent).

In a separate analysis, the researchers analyzed data from the 1992-2015 Tobacco Use Supplement to the Current Population Survey to assess whether underrepresented minority young adults who were exposed to affirmative action bans during their later high school years had continued smoking cigarettes into young adulthood (ages of 19 to 30 years). The researchers found that 1.8 percent more young adults who were in high school at the time an affirmative action ban was enacted in their state still smoked, compared to those living in states with no ban.

In contrast to their findings among underrepresented minority students, the researchers reported no change in smoking or alcohol use rates among white high schoolers and young adults in response to the affirmative action bans.

While the underlying mechanisms behind the health risk behaviors deserve further study, the authors point to several potential factors that could explain the spike in rates. Affirmative action bans may signal to underrepresented minority teenagers that structural racism persists or that they are less valued, the authors said. Increased competition for limited slots and academic stress among underrepresented minority students could also play a role.

"The findings align with a growing evidence base demonstrating that social policy is health policy," said senior author Alexander C. Tsai, MD, PhD, an associate professor of Psychiatry at Massachusetts General Hospital and Harvard Medical School. "In this specific case, our study shows that economic opportunity can have a meaningful impact on shaping population health."

Venkataramani added, "when we evaluate the merits of social and economic policies, we tend to focus on social and economic benefits. But ones' potential health consequences should be considered, too."

GAINESVILLE, Fla. --- Feet from the raw bars and sherbet-colored condominiums of Florida's Cedar Key, researchers discovered a new species of egg-sucking sea slug, a rare outlier in a group famous for being ultra-vegetarians.

Named Olea hensoni in honor of Muppets creator Jim Henson, the slug belongs to the sacoglossans, a group of more than 300 species that are such enthusiastic eaters of plants that many of them turn green and some resemble leaves. A few species, nicknamed "solar-powered slugs," have even developed the ability to keep algae alive inside their bodies to photosynthesize their food for them, becoming a fusion of plant and animal.

But O. hensoni has gone rogue, joining two other sacoglossan species - Olea hansineensis from the northeast Pacific and Calliopaea bellula in the Mediterranean - that abandoned a diet of seaweed to prey on the eggs of their fellow slugs and snails.

"In the middle of this group of super-herbivores, there are a couple of species that have rebelled in 'The Hills Have Eyes' kind of way and have gone almost full-blown cannibal," said Patrick Krug, professor of biological sciences at California State University. "These are like the Venus fly traps of the slug world. They've switched from being harmless, friendly creatures to predators."

In 2017, Cedar Key's waterfront still bore wreckage from Hurricane Hermine when Gustav Paulay, Florida Museum curator of invertebrate zoology, slipped on divers boots and walked onto a sand flat exposed by the low tide. He was scouting for nudibranchs, worms, sea snails and crabs to show his students. Picking up a Jell-O-like egg mass, he spotted a sea slug about the size of a grain of rice inside.

"I assumed it was a well-known species," he said. "I know its relative from the northeast Pacific quite well, so I figured, 'Okay, good, we got an Olea' and put it in the bag."

It wasn't until he contacted Krug, a sacoglossan expert, that he realized how unique the slug was.

"I sent it to Pat, and he was like, 'Oh my God! You got something weird that's not known from the western Atlantic,'" Paulay said. "What I found interesting was that this was the third example in the world of this feeding mode in this lineage of animals. I thought there were a lot more of them. I was tickled that we got one in Florida."

Krug said finding an egg-sucking slug in the Gulf of Mexico was "crazy."

"It was really surprising that a member of this group would show up in the waters around Florida because the other two species are from cold, northern waters," he said.

Even odder, O. hensoni is far more closely related to the Pacific egg-sucking slug than the Mediterranean one.

"That makes no sense at all," Krug said. "But that's what the DNA and the anatomy tell us. It's just a relic of a very old lineage that presumably got trapped in the Caribbean a long time ago and became isolated from its Pacific relatives."

Paulay said O. hensoni is a prime example of how much marine life remains to be discovered, even in the aquatic equivalent of a backyard.

"Cedar Key is a well-studied area, and it's still yielding new species," he said. "You don't need a scuba tank to find them. You just need to walk out in your flip-flops and look under your feet."

Although O. hensoni is only the third documented species of egg-eating slug, Paulay recalled seeing other slugs preying on egg masses during his fieldwork in the Indo-Pacific.

"They're probably in quite a few places, but nobody has ever looked," he said. "One of the things I'm pretty bummed about is I've seen sucking slugs elsewhere, but I've never bothered to go after them."

The researchers are not sure when the slugs made the plant-to-egg dietary switch or why, but speculate that egg capsules offer a nutritious and largely untapped food resource. Slugs and snails protect their eggs by encasing them by the thousands inside a mucous ball, an effective barrier against many would-be predators. But egg-sucking slugs have successfully developed a way to bulldoze their way inside, Krug said.

"Unlike the switchblade-like tooth of its plant-eating relatives, Olea has a tooth nubbin, which it can punch into jelly-like egg masses to suck out the eggs or embryos like someone sucking up boba from bubble tea," he said.

Like other sea slugs, O. hensoni is hermaphroditic, having both male and female reproductive parts. Because genitalia can be useful for identifying slug species, the researchers coated the slug's penis with gold and imaged it with a scanning electron microscope. Krug and Paulay did not observe O. hensoni reproducing in the lab, but the needle-like shape of its male genitalia may indicate that it engages in the "penis fencing" reproductive behavior seen in some sacoglossans and flatworms.

"It's pretty extreme as penial stylets go, so it looks like it's used for hypodermic insemination or for anchoring inside a sperm receptacle organ," Krug said. "It's a lot bigger than a lot of stylets I see in species that engage in some pretty dramatic fencing behaviors."

Naming the slug after Jim Henson was an idea that came to Krug as he was thinking about O. hensoni's creamy brown to yellow coloring - a standout in a group that is iconically green.

"It made me think of Kermit the Frog's song 'It's not Easy Being Green,'" he said. "That made me laugh because I remember being a kid, eating eggs for breakfast and watching 'Sesame Street.'"

As far as Krug knows, this is the first animal named after Henson.

"Jim Henson was one of those people who created things that were educational, positive and impactful and made the world a better place. That's something that should be honored."

Hilton de Castro Galvão Filho, who began the research in Krug's lab and is now at the University of São Paulo, is the study's lead author.

MISSOULA - Slow-growing ponderosa pines may have a better chance of surviving longer than fast-growing ones, especially as climate change increases the frequency and intensity of drought, according to new research from the University of Montana.

Researchers found that ponderosa longevity might hinge on the shape of microscopic valve-like structures between the cells that transport water through the tree.

The study, led by UM alumna Beth Roskilly and Professor Anna Sala, was published in the Proceedings of the National Academy of Sciences this week. The researchers sampled growth rates of ponderosa pine trees of varying ages at two remote sites in Idaho. They also studied structural traits of the trees' xylem - vascular tissue that transports water and minerals through the wood and provides structural support.

Their findings reveal that some young trees grow quickly while others grow slowly. But old ponderosa pine trees - those older than 350 years - are slow growers compared to younger trees, and these individual trees have always been slow growing, even when they were young.

In contrast to predictions, slow-growing trees, whether old or young, did not produce denser, tougher wood, which might have made the trees more resistant to disease or decay. Instead, a key difference between fast and slow growers resides in a microscopic valve-like structure between the cells that transport water in the wood, called the pit membrane. The unique shape of this valve in slow-growing trees provides greater safety against drought, but it slows down water transport, limiting growth rate.

"Ponderosa pines, like people, cannot have it all," said Roskilly, the paper's lead author. "Drought resistance contributes to longevity but also to slow growth. In other words, there is a fundamental tradeoff based on xylem structure. Our study suggests that trees with fast growth become large quickly, which can be beneficial for young trees competing for resources, but they are more vulnerable to drought and can die at earlier ages. On the other hand, trees that grow slowly are more drought resistant, which enhances longevity."

Roskilly earned her UM master's degree in organismal biology, ecology and evolution in 2018, and the study is a result of her degree work in UM's College of Humanities and Sciences.

"Ancient trees are special for many reasons," said Sala, a professor in UM's Division of Biological Sciences and an adjunct professor in the W.A. Franke College of Forestry and Conservation. "They are beautiful, they make the highest quality musical instruments, they help maintain diversity, and they store atmospheric carbon in wood for a long time. But the results of this research also suggest they are special because forest managers cannot make just any ponderosa pine tree live for centuries no matter how hard they try. For ponderosa pines to become centennials, their wood must possess this unique structure."

[Background]

In Japan, tea farms are found in warm areas, whose northern limit is Ibaraki prefecture, where green tea has been produced. However, black tea was also manufactured from the mid-19th century and, at one time, Japan exported more than 5,000 tons of black tea of Japanese origin. With Japan's economic growth in the second half of the 20th century, Japanese black tea lost its economic competitiveness and finally disappeared. Nonetheless, from the dawn of the 21st century, black tea manufacturing has been revitalized and production has grown. In 2007, the black tea manufactured by Satsuma Eikokukan in Kagoshima prefecture won a gold medal in the Great Taste Awards in the UK.

In general, a new industry and its market are not created by gradual changes in existing markets. Signs of opportunities for new products are very small and must be sought carefully. Here, the manufacture of black tea in Japan is seen as the creation of a new market. We studied the history of black tea in Japan, tea species, technological innovation and other factors. In addition, as a case study, black tea production in Sashima, Ibaraki prefecture, is elaborated.

[Results]

In mid-19th century, the Japanese black tea industry was born from the government's encouragement to tea producers to engage in black tea manufacturing. Black tea manufacturing suitable for the Japanese climate was sought and production increased. Improvements were made by using varieties of tea plant and in 1951 the quality of Japanese black tea was highly appreciated in the London tea market. The export reached its peak in 1954, contributing to the acquisition of foreign currency. However, due to the subsequent economic growth of Japan, labor shortages and higher wages made the cost of Japanese black tea manufacturing much higher, which led to loss of international competitiveness. On the other hand, black tea imports expanded rapidly from 1964 to 1974, of which 65% was in the form of tea bags. In 1986, black tea was first sold in bottles. Consumption and imports increased sharply and in 1997 black tea imports reached nearly 20,000 tons (Figure 1).

The manufacture of Japanese black tea decreased to almost zero around the end of the 20th century. However, the 1996 tea boom stimulated Japanese black tea manufacturing again; in 2010, 84 tons were manufactured, which further grew to more than 200 tons in 2016. The Japanese black tea is consumed domestically. In 2007, the black tea manufactured by Satsuma Eikokukan in Kagoshima prefecture won a gold medal in the Great Taste Awards in the UK.

Japanese green tea is mainly produced in Shizuoka, Kagoshima and Mie prefectures, and black tea manufacturing overlaps the green tea production (Figure 2). Tea is made from the leaves of the tea plant, Camellia sinensis, of which there are two main varieties, Assam or Indian (C. sinensis var. assamica) and Chinese (C. sinensis var. sinensis). It is considered that Assam tea is suitable for black tea and Chinese tea for green tea. While Assam tea is cultivated in hot and humid areas like Indonesia, Chinese tea is grown in China, Japan and Taiwan for the production of green tea. It is rather difficult to cultivate Assam tea in Japan, but for the past half century, breeding has been improved by mixing Assam and Chinese tea sorts.

In general, tea contains tannin (catechin), caffeine, and theanine (a free amino acid). Tannin is astringent and caffeine has a bitter flavor. Assam tea contains higher levels of both tannin and caffeine, so black tea produced in southern countries has a stronger flavor than Japanese black tea. On the other hand, theanine tastes of umami and sweetness but is chemically fragile under sunlight. The reason why tea fields are located in foggy mountainous areas is that the leaves are not overexposed to sunlight, which enables theanine to remain in tea leaves. In addition, the metabolism of theanine is influenced by temperature, being accelerated as the temperature rises. Therefore, theanine and tannin differ in content depending on when the tea leaves are harvested. Black tea made from leaves picked during the summer contains more tannin; thus, it is possible to make tea with a strongly astringent flavor.

The manufacturing of black tea includes four processes: withering, rolling, fermenting, and drying. Fermentation is a particularly highly skilled process, requiring technical knowledge of humidity, temperature and the process of fermentation. While it only takes 3-4 hrs to produce green tea by machine, black tea manufacturing takes about 20 hrs. The revitalization and dissemination of Japanese black tea occurred thanks to innovations in product manufacturing. Entrepreneurial farmers accomplished improvements in manufacturing technology by innovations in fermentation and by learning about the climate, varieties and fermentation methods in different countries and regions.

A growing market needs a new supply chain. In the Japanese black tea market, tea farmers sell their product directly to retailers and blenders or sell it via the Internet. One of the important characteristics of direct selling, as described below concerning the case study of Sashima, is that the communication channel is open between tea farmers and consumers. Tea farmers can take advantage of feedback from consumers as a driving force for subsequent innovation. Advanced consumers play important roles in quality evaluation.

In the Sashima region of Ibaraki prefecture, about 30 farmers produce green tea and 8 out of 30 farmers also manufacture black tea. They used to produce green tea with a brand name, Sashima tea, but due to shrinkage of the green tea market, a new market had to be explored. Farmers who had been cultivating Assam tea started manufacturing black tea. As described above, humidity and temperature management of the fermentation process are of particular importance and high-level technology is required for black tea manufacturing. Researchers and leading farmers visited tea farms in Sri Lanka and made contacts with universities, which brought about improvements in the manufacturing technology of black tea. They gave important advice to tea farmers including those in Sashima. Tea farmers in Sashima put in place a feedback system from consumers for improvement of product quality. This was a new challenge for tea farmers and had an impact on the creation of a market for Japanese black tea. Furthermore, the technology was disseminated by technology transfer. This way, Sashima black tea was born.

[Discussion]

In the process of market development for Japanese black tea, entrepreneurial tea farmers explored black tea manufacturing along with green tea production. The business opportunities were established via the connections of green tea farmers, retailers and consumers. Innovations in the fermentation process were accomplished by leading farmers and researchers through those connections, which was one of the keys to the success of market exploration for Japanese black tea. Moreover, the fermentation technologies were transferred to other black tea farmers. This transfer of core technologies increased the number of reliable manufacturers. As a result, they were successful in rapidly expanding the Japanese black tea market.

On the other hand, creation of a new market may cause cannibalization of existing businesses and the Japanese black tea market should be no exception. If black tea was sold in the existing green tea market, cannibalization of green tea and black tea might have happened. For that reason, a new unique online channel for Japanese black tea was created. Especially in the Sashima case, it was important that a feedback system was introduced between tea farmers and consumers for improving the product quality (Figure 3). This was a big challenge for tea farmers and had an impact on the creation of a market for Japanese black tea.

PULLMAN, WA-- College students who viewed alcohol advertisements that included objectified images of women were less likely than others to report intentions to intervene in alcohol-facilitated sexual assault situations in a study published in the Journal of Health Communication.

The role of alcohol in sexual assault has long been an interest among health communication scholars, but few have examined whether alcohol advertising may contribute to beliefs associated with alcohol-facilitated sexual assault.

Professors at The Edward R. Murrow College of Communication and College of Agriculture, Human, and Natural Resource Sciences at Washington State University analyzed the influence of alcohol advertisements on college students' intentions to intervene in sexual assault situations. The authors conclude that individuals' perceptions of alcohol advertisements moderate the relationship between exposure to objectifying alcohol advertisements and intentions to intervene in sexual assault situations.

"This study estimates some of the ways alcohol advertising and the objectification of women in alcohol ads could affect college students' intentions to intervene in sexual assaults linked to alcohol," said Stacey Hust, associate professor in the college of communication and the study's principal investigator. "Understanding the real-life consequences of exposure to and perceptions of this type of advertising can help mitigate risk of sexual assault among college students, female college students in particular."

The authors found that while most of the 1208 college students at a northwestern university that participated in the study reported that they intended to intervene in an alcohol-facilitated sexual assault, women reported significantly greater intentions to intervene than men. Further, exposure to alcohol ads and perceptions of the women in the ads made a difference as to whether individuals expressed intentions to intervene in a sexual assault situation.

"We know that a majority of alcohol advertisements use women's sex appeal to sell their product, and many of these ads objectify women or include sexual connotations," Hust said. "Our results suggest that exposure to this type of advertising coupled with use of alcohol in settings where bystanders are present has an effect on whether those bystanders intend to take steps to prevent or interrupt a sexual assault situation when it occurs."

The results of the study largely support objectification theory, which suggests that perceptions of women as powerless objects result in individuals' negative treatment of women.

Kathleen Boyce Rodgers, associate professor in WSU's Department of Human Development and the second author of the study, explains that we need to help emerging adults make sense of media portrayals of women.

"Media professionals need to be conscientious of the portrayals of women in their messages," she said. "Understanding viewers' perception of female models in advertising and using this knowledge to advocate for media literacy is a step in the right direction."

BUFFALO, N.Y. -- Modern hyenas are known as hunters and scavengers in Asian and African ecosystems such as the savanna.

But in ancient times, these powerful carnivores also roamed a very different landscape, inhabiting the frigid Arctic during the last ice age, according to a new study led by the University at Buffalo.

The research, which will be published on June 18 in the journal Open Quaternary, reports on the first known fossils of hyenas from the Arctic. The study and all information in this press release are embargoed until 6 a.m. U.S. Eastern Time on Tuesday, June 18.

The study reveals that two ice age fossil teeth discovered in Yukon Territory in Canada belonged to the so-called "running hyena" Chasmaporthetes. The specimens, recovered in the 1970s, were tentatively thought to be from hyenas by previous paleontologists, but the new paper is the first to confirm the fossils' identity and report on them in detail, assigning them a genus based on comparisons to a global sample of hyena fossils.

The findings fill an important gap in scientists' knowledge of how hyenas reached North America. Previously, Chasmaporthetes fossils had been found as far north as Mongolia in Asia and the southern United States in North America, with no sites in between.

"Fossils of this genus of hyenas had been found in Africa, Europe and Asia, and also in the southern United States. But where and how did these animals get to North America? The teeth we studied, even though they were just two teeth, start to answer those questions," says paleontologist Jack Tseng, PhD, the paper's first author and an assistant professor of pathology and anatomical sciences in the Jacobs School of Medicine and Biomedical Sciences at UB.

How hyenas got to North America

Ancient hyenas likely entered North America via Beringia, an area, including Alaska and Yukon Territory, that connects Asia with North America during periods of low sea levels. From there, the animals made their way south all the way to Mexico, scientists say.

The newly described fossils are important in part because they provide the first proof of ancient hyenas living in Beringia.

"It is amazing to imagine hyenas thriving in the harsh conditions above the Arctic Circle during the ice age," says study co-author Grant Zazula, PhD, Government of Yukon paleontologist. "Chasmaporthetes probably hunted herds of ice age caribou and horses or scavenged carcasses of mammoths on the vast steppe-tundra that stretched from Siberia to Yukon Territory."

"Our previous understanding of where these far-ranging hyenas lived was based on fossil records in southern North America on one hand, and Asia, Europe and Africa on the other," Tseng says. "These rare records of hyenas in the Arctic fill in a massive gap in a location where we expected evidence of their crossing between continents, but had no proof until now."

The fossil teeth are most likely between about 1.4 million and 850,000 years old, with ages more likely closer to the older figure, according to the researchers' analysis. But the first hyenas crossed into North America long before that, as the earliest known hyena fossils on the continent date back about 5 million years, Tseng says.

Enigmatic fossil teeth identified

The fossil teeth were collected in the 1970s during paleontological expeditions in the remote Old Crow River region in northern Yukon Territory. One tooth was discovered by Richard "Dick" Harington, Gerry Fitzgerald and Charlie Thomas, and the other by Brenda Beebe and William Irving.

The specimens -- tucked away in the collections of the Canadian Museum of Nature in the Ottawa, Ontario area -- are among 50,000 other fossils recovered from the area over the last century.

The identity of the fossil teeth remained an enigma until they captured Tseng's attention, sparked by the re-discovery of decades-old notes by study co-author Lars Werdelin, paleontologist in the Swedish Museum of Natural History.

Tseng drove to Ottawa from Buffalo in February 2019 to view the specimens. As an expert on the evolution and fossil record of hyenas, he was able to identify the teeth as belonging to the genus Chasmaporthetes.

Though there are only four living species of hyena today (three bone-crushing species, plus the ant-eating aardwolf), ancient hyenas had a diverse family history, with many dozens of species found in localities spanning the Northern Hemisphere.

Hyenas disappeared from North America before the first people arrived. Although the reasons for this extinction between 1 and 0.5 million years ago remain unclear, it is possible that the animals' bone-crushing, scavenging niche was replaced by the impressive short-faced bear Arctodus simus, which lived across North America until the end of the ice age about 12,000 years ago.