Earth

Without their keen sense of smell, mosquitoes wouldn't get very far. They rely on this sense to find a host to bite and spots to lay eggs.

And without that sense of smell, mosquitoes could not locate their dominant source of food: nectar from flowers.

"Nectar is an important source of food for all mosquitoes," said Jeffrey Riffell, a professor of biology at the University of Washington. "For male mosquitoes, nectar is their only food source, and female mosquitoes feed on nectar for all but a few days of their lives."

Yet scientists know little about the scents that draw mosquitoes toward certain flowers, or repel them from others. This information could help develop less toxic and better repellents, more effective traps and understand how the mosquito brain responds to sensory information -- including the cues that, on occasion, lead a female mosquito to bite one of us.

Riffell's team, which includes researchers at the UW, Virginia Tech and UC San Diego, has discovered the chemical cues that lead mosquitoes to pollinate a particularly irresistible species of orchid. As they report in a paper published online Dec. 23 in the Proceedings of the National Academy of Sciences, the orchid produces a finely balanced bouquet of chemical compounds that stimulate mosquitoes' sense of smell. On their own, some of these chemicals have either attractive or repressive effects on the mosquito brain. When combined in the same ratio as they're found in the orchid, they draw in mosquitoes as effectively as a real flower. Riffell's team also showed that one of the scent chemicals that repels mosquitoes lights up the same region of the mosquito brain as DEET, a common and controversial mosquito repellant.

Their findings show how environmental cues from flowers can stimulate the mosquito brain as much as a warm-blooded host -- and can draw the mosquito toward a target or send it flying the other direction, said Riffell, who is the senior author of the study.

The blunt-leaf orchid, or Platanthera obtusata, grows in cool, high-latitude climates across the Northern Hemisphere. From field stations in the Okanogan-Wenatchee National Forest in Washington state, Riffell's team verified past research showing that local mosquitoes pollinate this species, but not its close relatives that grow in the same habitat. When researchers covered the flowers with bags -- depriving the mosquitoes of a visual cue for the flower -- the mosquitoes would still land on the bagged flowers and attempt to feed through the canvas.
Orchid scent obviously attracted the mosquitoes. To find out why, Riffell's team turned to the individual chemicals that make up the blunt-leaf orchid's scent.

"We often describe 'scent' as if it's one thing -- like the scent of a flower, or the scent of a person," said Riffell. "Scent is actually a complex combination of chemicals -- the scent of a rose consists of more than 300 -- and mosquitoes can detect the individual types of chemicals that make up a scent."

Riffell describes the blunt-leaf orchid's scent as a grassy or musky odor, while its close relatives have a sweeter fragrance. The team used gas chromatography and mass spectroscopy to identify dozens of chemicals in the scents of the Platanthera species. Compared to its relatives, the blunt-leaf orchid's scent contained high amounts of a compound called nonanal, and smaller amounts of another chemical, lilac aldehyde.

Riffell's team also recorded the electrical activity in mosquito antennae, which detect scents. Both nonanal and lilac aldehyde stimulated antennae of mosquitoes that are native to the blunt-leaf orchid's habitat. But these compounds also stimulated the antennae of mosquitoes from other regions, including Anopheles stephensi, which spreads malaria, and Aedes aegypti, which spreads dengue, yellow fever, Zika and other diseases.

Experiments of mosquito behavior showed that both native and non-native mosquitoes preferred a solution of nonanal and lilac aldehyde mixed in the same ratio as found in blunt-leaf flowers. If the researchers omitted lilac aldehyde from the recipe, mosquitoes lost interest. If they added more lilac aldehyde -- at levels found in the blunt-leaf orchid's close relatives -- mosquitoes were indifferent or repelled by the scent.

Using techniques developed in Riffell's lab, they also peered directly into the brains of Aedes increpitus mosquitoes, which overlap with blunt-leaf orchids, and a genetically modified strain of Aedes aegypti previously developed by Riffell and co-author Omar Akbari, an associate professor at UC San Diego. They imaged calcium ions -- signatures of actively firing neurons -- in the antenna lobe, the region of the mosquito brain that processes signals from the antennae.

These brain imaging experiments revealed that nonanal and lilac aldehyde stimulate different parts of the antenna lobe -- and even compete with one another when stimulated: The region that responds to nonanal can suppress activity in the region that responds to lilac aldehyde, and vice versa. Whether this "cross talk" makes a flower attractive or repelling to the mosquito likely depends on the amounts of nonanal and lilac aldehyde in the original scent. Blunt-leaf orchids have a ratio that attracts mosquitoes, while closely related species do not, according to Riffell.

"Mosquitoes are processing the ratio of chemicals, not just the presence or absence of them," said Riffell. "This isn't just important for flower discrimination -- it's also important for how mosquitoes discern between you and I. Human scent is very complex, and what is probably important for attracting or repelling mosquitoes is the ratio of particular chemicals. We know that some people get bit more than others, and maybe a difference in ratio explains why."

The team also discovered that lilac aldehyde stimulates the same region of the antenna lobe as DEET. That region may process "repressive" scents, though further research would need to verify this, said Riffell. It's too soon to tell if lilac aldehyde may someday be an effective mosquito repellant. But if it is, there is an added bonus.

"It smells wonderful," said Riffell.

BELLINGHAM, Washington, USA, and CARDIFF, UK - Recent advances in computer graphics are making it possible to create computer-generated (CG) representations of human beings that are difficult to distinguish from their real-world counterparts. "Digital human face detection in video sequences via a physiological signal analysis," a paper published today in the Journal of Electronic Imaging (JEI), presents a viable, innovative way to discern between natural humans (NAT) and CG faces within the context of multimedia forensics, using individuals' heart rate as the discriminating feature. JEI is co-published by SPIE, the international society for optics and photonics, and by the Society for Imaging Science and Technology (IS&T).

Humans present a pulse signal that can be automatically extracted from a video sequence; virtual humans do not. In their paper, Mattia Bonomi and Giulia Boato demonstrate that by focusing on an algorithm for pulse-rate estimation from human faces and calculating statistics from that heart rate, they can classify the input face as CG or NAT.

"Recent advances in machine learning and computer graphics have led to the rapid development of deep fakes, where the face of a real person in a video is replaced by a computer generated one," notes JEI Editor-in-Chief Karén Egiazarian. "This technology is openly available nowadays, and, together with its wide use in the movie industry and advertisements, it has been also used by fraudsters. But how to distinguish a human face from a computer generated one? Bonomi and Boato address this question by proposing and applying a physiological signal analysis, extracting the heart rate from the video of human face, and using it as a discriminating factor."

The article authors are Mattia Bonomi and Giulia Boato, both of the University of Trento, Department of Engineering and Computer Science, Trento, Italy.

Karén Egiazarian, a professor of computing sciences at Tampere University, is the editor-in-chief of JEI. The journal is co-published digitally by the Society for Imaging Science and Technology and by SPIE in the SPIE Digital Library, which contains more than 500,000 publications from SPIE journals, proceedings, and books, with approximately 18,000 new research papers added each year.

Fires started by people have steadily increased in recent decades, sparking a major shift in U.S. wildfire norms, according to a new CU Boulder-led study.

At a national scale, fires are broadly becoming larger and more frequent with fire season lengths extending over time. At the same time, wildfires started by people are more frequent, smaller, less hot and occur over longer seasons than fires started by lightning.

"The leading cause of wildfire ignitions in the United States is shifting away from lightning and towards human activity," said Megan Cattau, a former CIRES and CU Boulder Earth Lab scientist and lead author on a study published today in Global Ecology and Biogeography. "And it's looking like this is going to be our new normal."

The shift toward longer fire seasons with more frequent fires presents new challenges to U.S. wildfire managers and firefighters, the authors say.

"We can't even call it a fire season anymore--it's nearly all year round," added Cattau, now an assistant professor of Human Environment Systems at Boise State University.

Many studies have examined the impacts of fuel and climate on U.S. wildfire patterns, but before this study scientists had not yet comprehensively examined the relationship between ignition source and the physical characteristics of fire and their trends over time. Cattau and her colleagues pulled data from multiple sources and looked at ignition trends in roughly 3300, 50-km grid cells covering the United States, between 1984 and 2016.

Ignition type matters, in part, because of fundamental differences between anthropogenic ignitions and lightning ignitions. Wildfires kindled by lightning tend to be larger and more intense, but only occur during times during the year when weather conditions are conducive to storms. And anthropogenic fires occur more frequently and over a much longer season but are less "hot" and smaller on average.

Say people accidentally spark a wildfire in a typically low-fire season like early spring: It may not spread particularly quickly. And human-started fires can also burn closer to cities where firefighters can respond more quickly.

The team analyzed a suite of satellite data and 1.8 million government records to identify the wildfire ignition patterns across the country. Satellite records capture data from a long period of time but cannot distinguish between prescribed fires, human-ignited fires or lightning-ignited fires. So Cattau and her team also turned to the Fire Program Analysis Fire-Occurrence Database from the U.S. Forest Service, the first large-scale national database to include a comprehensive record of ignition type.

They found that in the majority of the country, human-ignited fires were more frequent than lightning-triggered ones. In fact, every single grid east of the Great Plains, and much of the coastal West was human-dominated over the last 30 years.

"The shift to more human-caused fires results in decreased fire intensity and size, but that may not necessarily be a good thing," said Cattau. "There's been a focus on extreme fires, but any deviation from historical fire patterns, from what that land evolved with, can cause problems. Fire is part of the ecosystem. And now its role is changing."

People have been setting fires, deliberately and accidentally, since the pre-industrial age. But the impact of modern-day climate change on wildfire (e.g. warming trends and drier fuels) combined with more extensive land cover change and the human tendency to start fires represents a unique cocktail of conditions, Cattau said.

"As our world sees increased development, we can also expect to see increased human ignitions," said Cattau. "This can impact people's safety, especially those from vulnerable populations. And this shift is also bringing fires into places where there wasn't fire before, which can damage ecosystems."

Moving forward, the authors say there's a clear need to develop one complete database that fuses wildfire record sources, to serve policymakers and fire managers making decisions in a changing world.

LA JOLLA--(January 21, 2020) People with osteoarthritis, or "wear and tear" arthritis, have limited treatment options: pain relievers or joint replacement surgery. Now, Salk researchers have discovered that a powerful combination of two experimental drugs reverses the cellular and molecular signs of osteoarthritis in rats as well as in isolated human cartilage cells. Their results were published in the journal Protein & Cell on January 16, 2020.

"What's really exciting is that this is potentially a therapy that can be translated to the clinic quite easily," says Juan Carlos Izpisua Belmonte, lead author and a professor in Salk's Gene Expression Laboratory. "We are excited to continue refining this promising combination therapy for human use."

Affecting 30 million adults, osteoarthritis is the most common joint disorder in the United States and its prevalence is expected to rise in coming years due to the aging population and increasing rate of obesity. The disease is caused by gradual changes to cartilage that cushions bones and joints. During aging and repetitive stress, molecules and genes in the cells of this articular cartilage change, eventually leading to the breakdown of the cartilage and the overgrowth of underlying bone, causing chronic pain and stiffness.

Previous research had pinpointed two molecules, alpha-KLOTHO and TGF beta receptor 2 (TGFβR2), as potential drugs to treat osteoarthritis. αKLOTHO acts on the mesh of molecules surrounding articular cartilage cells, keeping this extra-cellular matrix from degrading. TGFβR2 acts more directly on cartilage cells, stimulating their proliferation and preventing their breakdown.

While each drug alone had only moderately curbed osteoarthritis in animal models of the disease, Izpisua Belmonte and his colleagues wondered if the two drugs would act more effectively in concert.

“We thought that by mixing these two molecules that work in different ways, maybe we could make something better,” says Paloma Martinez-Redondo, a Salk postdoctoral fellow and co-first author of the new study.

The researchers treated young, otherwise healthy rats with osteoarthritis with viral particles containing the DNA instructions for making αKLOTHO and TGFβR2.

Six weeks after the treatment, rats that had received control particles had more severe osteoarthritis in their knees, with the disease progressing from stage 2 to stage 4. However, rats that had received particles containing αKLOTHO and TGFβR2 DNA showed recovery of their cartilage: the cartilage was thicker, fewer cells were dying, and actively proliferating cells were present. These animals’ disease improved from stage 2 to stage 1, a mild form of osteoarthritis, and no negative side effects were observed.

“From the very first time we tested this drug combination on just a few animals, we saw a huge improvement,” says Isabel Guillen-Guillen, the paper’s co-first author. “We kept checking more animals and seeing the same encouraging results.”

Further experiments revealed 136 genes that were more active and 18 genes that were less active in the cartilage cells of treated rats compared to control rats. Among those were genes involved in inflammation and immune responses, suggesting some pathways by which the combination treatment works.

To test the applicability of the drug combination to humans, the team treated isolated human articular cartilage cells with αKLOTHO and TGFβR2. Levels of molecules involved in cell proliferation, extra-cellular matrix formation and cartilage cell identity all increased.

"That's not the same as showing how these drugs affect the knee joint in humans, but we think it's a good sign that this could potentially work for patients," says Martinez-Redondo.

The research team plans to develop the treatment further, including investigating whether soluble molecules of the αKLOTHO and TGFβR2 proteins can be taken directly, rather than administered through viral particles. They also will study whether the combination of drugs can prevent the development of osteoarthritis before symptoms develop.

"We think that this could be a viable treatment for osteoarthritis in humans," says Pedro Guillen, director of the Clinica CEMTRO and co-corresponding author.

Reno, Nev. - Using a 22-year dataset of plant-caterpillar-parasitoid interactions collected within a patch of protected Costa Rican lowland Caribbean forest, scientists report declines in caterpillar and parasitoid diversity and density that are paralleled by losses in an important ecosystem service: biocontrol of herbivores by parasitoids.

The study by University of Nevada, Reno researchers, published in Scientific Reports this week, reveals distressing declines among common caterpillar genera and the ecosystem services provided by their natural enemies.

"Declines in herbivore and enemy diversity, as well as parasitism frequency, are partly explained by changes in climate, including increases in extreme precipitation events and increases in mean temperatures," lead author of the study Danielle Salcido said.

In 2017, the observation by Professor Lee Dyer, of the University's College of Science, that La Selva Biological Research Station, Costa Rica experienced more frequent flooding events, became the catalyst for a study led by graduate student Salcido to examine patterns in extreme precipitation events and their potential ecological impact for plant-caterpillar-parasitoid interactions in this lowland tropical forest.

"La Selva is an isolated patch of forest surrounded by agriculture that is responsible for global exports of banana, pineapple and palm," Salcido said. "Habitat patches like La Selva are source populations of parasitoids that control pest populations in surrounding agriculture plantations. Reductions in parasitism by specialized parasitoids threaten this service and ultimately ecosystem health within the forest."

Along with the help of coauthor and University of Nevada, Reno professor, biologist and butterfly expert Matthew Forister, these researchers found staggering declines in caterpillar and parasitoid diversity and density across the 22 years of the study. More than 40% of the 64 common caterpillar genera collected declined in frequency- a result that suggested the loss of entire groups of caterpillar.

Researchers also found an ecological cost associated with the observed losses. Tandem with declines in diversity, was the reduction in parasitism across years- a natural form of biocontrol and important ecosystem service. Observed declines represented a 30% reduction in parasitism over the next 100-years.

Increased precipitation variability and shifts in mean maximum and minimum temperatures were the most important climate variables associated with declines in diversity.

"We show climate change partially explains the observed declines," Salcido said. "The variable with largest effect in all models was the effect of time, and indicates the role of unmeasured variables such as surrounding land-use change and pesticide use."

In the decades prior to the study, much of the forest surrounding La Selva was deforested for pasture which was converted to high-yield, high input plantation farming such that pesticide use increased substantially during the years of the study.

Time-lag effects of extreme climate events were a notable contributor to the reduction in parasitism.

"We found floods in a given year affected parasitism in the subsequent year," she said. "Caterpillar-parasitoid interactions are intimately linked and depend on narrow windows for synchronous development. Subtle shifts in host and parasitoid population cycles due to variable lag effects can have major consequences for these highly-specialized and synched interactions."

Declines in insect biodiversity reported in this study come as little surprise amidst a recognized global biodiversity crisis. This study maintains a level of urgency to the matter of insect declines and more importantly, has revealed the vulnerability of the most speciose regions and taxa even within protected habitats, and the role of extreme climate events on ecosystem function.

"This dataset represents one of few of its kind and is notable for the contribution by Earthwatch community scientists," Salcido said. "Ideally results like ours provide an impetus for policy change that promotes research, conservation and management. In the least, we hope it motivates continued research related to the ecological effects of global change drivers in the tropics."

The data used for this study is primarily collected by continuous teams of community scientists the scientists bring to the site each year, which highlights the importance of harnessing public participation for the success and longevity of long-term and continuous tropical collection and monitoring.

The Paper in the Nature research journal Scientific Reports, "Loss of dominant caterpillar genera in a protected tropical forest," was authored by Salcido, Forister, Humberto Garcia-Lopez and Dyer.

Forister and Dyer recently coauthored, with 70 other scientists from around the world, a second paper in the Nature publication Nature Ecology and Evolution titled "International scientists formulate a roadmap for insect conservation and recovery" that is testament to the call-to-action prompted from increased public awareness on insect declines. Their road map to insect conservation and recovery was published this week.

The Japanese art of origami (from ori, folding, and kami, paper) transforms flat sheets of paper into complex sculptures. Variations include kirigami (from kiri, to cut), a version of origami that allows materials to be cut and reconnected using tape or glue.

But while both art forms are a source of ideas for science, architecture, and design, each has fundamental limitations. The flat folds required by origami result in an unlockable overall structure, while kirigami creations can't be unfolded back into their original, flattened states because of the adhesive.

Taking inspiration from both art forms, researchers describe a new set of motifs for creating lightweight, strong, and foldable structures using soft materials. These kirigami structures can support 14,000 times their weight and, because they don't require adhesives or fasteners, can easily be flattened and refolded. Published in Physical Review X, the work was conducted by visiting graduate student Xinyu Wang and professor Randall Kamien of the University of Pennsylvania in collaboration with Simon Guest from the University of Cambridge.

Wang, a Ph.D. student at Southeast University, was interested in studying the mechanical properties of origami and kirigami structures and reached out to Kamien to start a new collaboration. After Wang arrived at the Kamien lab in September 2018, Kamien asked her to try some new designs using his group's set of rules for exploring kirigami structures.

Shortly thereafter, Wang showed Kamien a new design for a kirigami triangle that had tilted walls. Kamien was initially surprised to see that Wang had left the excess flaps from the cuts in place. "The usual kirigami route is to cut that off and tape it," says Kamien. Wang "found that, in this particular geometry, you can get the flaps to fit."

While a single triangle wasn't particularly strong on its own, the researchers noticed that when several were arranged in a repetitive design, the force they could support was much greater than expected. "Here was this structure that didn't require tape, it had cuts, and it was really strong," Kamien says. "Suddenly, we have this system that we hadn't anticipated at all."

To figure out what made this geometry so resilient, Wang made several versions of different "soft" materials, including paper, copper, and plastic. She also made versions where the cut flaps were taped, cut, or damaged. Using industry-grade tension and compression testing equipment at the Laboratory for Research on the Structure of Matter, the scientists found that the geometric structure could support 14,000 times its own weight. The tilted, triangular design was strongest when the flaps were undamaged and untapped, and it was also stronger than the same design with vertical walls.

With the help of Guest, the researchers realized that two deviations from the group's typical kirigami rules were key to the structure's strength. When the walls of the triangles are angled, any force applied to the top can be translated into horizontal compression within the center of the design. "With the vertical ones, there's no way to turn a downward force into a sideways force without bending the paper," says Kamien. They also found that the paper-to-paper overlap from leaving the cut flaps in place allowed the triangles to press up against their neighbors, which helped distribute the vertical load.

This paper is yet another example of how kirigami can be used as a "tool" for scientists and engineers, this time for creating strong, rigid objects out of soft materials. "We figured out how to use materials that can bend and stretch, and we can actually strengthen these materials," says Wang. One possible application could be to make inexpensive, lightweight, and deployable structures, such as temporary shelter tents that are strong and durable but can also be easily assembled and disassembled.

Kamien also pictures this Interleaved Kirigami Extension Assembly as a way to create furniture in the future. "Someday, you'll go to IKEA, you fold the box into the furniture, and the only thing inside is the cushion. You don't need any of those connectors or little screws," says Kamien.

Thanks to Wang's "inspired" design and Kamien's burgeoning collaboration with Wang and her advisors Jianguo Cai and Jian Feng , the possibilities for future ideas and designs are endless. "There were things about this study that are totally outside the scope of what a physicist would know," says Kamien. "It was this perfect blend of what I could do and what she could do."

Cyberbullying had the impact of amplifying symptoms of depression and post-traumatic stress disorder in young people who were inpatients at an adolescent psychiatric hospital, according to a new study published in the Journal of Clinical Psychiatry. The study addressed both the prevalence and factors related to cyberbullying in adolescent inpatients.

"Even against a backdrop of emotional challenges in the kids we studied, we noted cyberbullying had an adverse impact. It's real and should be assessed," said Philip D. Harvey, Ph.D., professor of psychiatry and behavioral sciences at the University of Miami Miller School of Medicine, who co-authored the paper "Cyberbullying and Its Relationship to Current Symptoms and History of Early Life Trauma."

He says children with a history of being abused were found to be more likely to be cyberbullied, suggesting that assessments for childhood trauma should also include assessments for cyberbullying. Likewise, children who report being cyberbullied should be assessed for a history of childhood trauma.

"Cyberbullying is possibly more pernicious than other forms of bullying because of its reach," Dr. Harvey says. "The bullying can be viral and persistent. To really be bullying, it has to be personal - a directly negative comment attempting to make the person feel bad."

The study helped to confirm other facts about cyberbullying:

Being online regularly or the amount of time spent on social media weren't determining factors in who was cyberbullied.

Cyberbullying cuts across all economic classes and ethnic backgrounds.

Adolescents who have been bullied in the past had a higher risk of being bullied again.

Studying Cyberbullying's Impact on an Inpatient Psychiatric Population

The study of 50 adolescent psychiatric inpatients ages 13 to 17 examined the prevalence of cyberbullying and related it to social media usage, current levels of symptoms and histories of adverse early life experience.

Conducted from September 2016 to April 2017 at a suburban psychiatric hospital in Westchester County, New York, the study asked participants to complete two childhood trauma questionnaires and a cyberbullying questionnaire.

Twenty percent of participants reported that they had been cyberbullied within the last two months before their admission. Half of the participants were bullied by text messages and half on Facebook. Transmitted pictures or videos, Instagram, instant messages and chat rooms were other cyberbullying vehicles.

Those who had been bullied had significantly higher severity of post-traumatic stress disorder (PTSD), depression, anger, and fantasy dissociation than those who were not bullied.

Links to Childhood Trauma

Participants who reported being cyberbullied also reported significantly higher levels of lifetime emotional abuse on the study's Childhood Trauma Questionnaire than those who were not bullied. These same young people did not report a significantly higher level of other types of trauma (physical abuse, sexual abuse, emotional neglect or physical neglect).

Further studies are needed to establish whether there may be some unique consequence of childhood emotional abuse that makes troubled teens more likely to experience or report cyberbullying.

Conclusions

While all of the participants in this study were psychiatric inpatients, those who had been bullied had significantly higher scores on PTSD, depression, anger, and dissociation scales than those who were not bullied. Dr. Harvey says this finding is consistent with past research.

Dr. Harvey encourages psychologists, psychiatrists and other counselors to routinely ask young people if they were abused or traumatized when they were younger and whether they are being bullied now.

He says adding these questions to the clinical evaluation of adolescents may bring to light symptoms that may have otherwise been ignored. Additionally, factors that may be causing or contributing to those symptoms can be targeted for specific intervention.

Parents and adolescents can take action to discourage bullying, Dr. Harvey says. "It's not hard to block someone on the Internet, whether it's texting, Facebook, Twitter, or sending pictures. Ask why are people choosing you to bully? If it's something you're posting, assess that and make a change."

Dr. Harvey collaborated on the study with Samantha Block Saltz, M.D., also with the University of Miami Miller School of Medicine, and David L. Pogge, Ph.D., of Winds Hospital in Katonah, New York.

Scientists have discovered that a non-invasive technique which could one day be used to treat Parkinson's disease, can successfully target a highly specific group of brain cells which play a key role in development of the condition.

In 2015, scientists demonstrated that a form of gene therapy could target and stimulate a group of nerve cells affected by the disease, called cholinergic neurons. These cells degenerate as the disease progresses.

Now, thanks to brain imaging technology, they have discovered that their method, which targets cells that produce specific brain chemicals, can also successfully stimulate another type of neuron through cell-to-cell interactions.

In a study published in the journal Neurotherapeutics, Dr Ilse Pienaar, Lecturer in Pharmacology at the University of Sussex, along with colleagues at Imperial College London and Invicro, a precision medicine company, reveal a clear communication pathway between cholinergic neurons and dopaminergic neurons, two major neurotransmitter systems found in the brain.

Dopaminergic neurons produce dopamine, but in Parkinson's disease, these levels are reduced as neurons deactivate and eventually die. This can cause a number of symptoms, including impaired movement.

Using a type of gene therapy in a rat model of Parkinson's, Dr Pienaar and her colleagues targeted cholinergic neurons, only to realise that a therapeutic knock-on effect was also felt by dopaminergic neurons. The originally stimulated cell was able to evoke a positive reaction in the receptive cell type, restoring dopaminergic functions.

With both groups of nerve cells stimulated, test subjects were seen to make a complete recovery including showing no more signs of movement and postural impairment.

Dr Ilse Pienaar, senior author of the study funded by the Medical Research Council, said: "When we used brain imaging, we found that as we activated cholinergic neurons, they then interacted directly with dopaminergic neurons.

"This seems to be a knock-on effect so by targeting this one set of neurons, we now know that we are able to also stimulate dopaminergic neurons, effectively restarting the production of dopamine and reducing symptoms.

"This is really important as it reveals more about how nerve systems in the brain interact, but also that we can successfully target two major systems which are affected by Parkinson's disease, in a more precise manner."

In the gene therapy technique, the team used a harmless virus to deliver a genetic modification to cholinergic neurons in rats rendered Parkinsonian. They then administered a drug designed to act as a 'switch' and stimulate target neurons.

The technique could, in future, provide a less invasive and more effective way to treat Parkinson's patients. While the disease can currently be managed by drugs, these tend to become ineffective after five years and present a number of side effects. An alternative is an invasive surgical procedure called deep brain stimulation (DBS) which uses electrodes to send pulses into the brain. However, this treatment produces mixed results and researchers believe this is because it stimulates every cell type rather than just the specific cells affected by Parkinson's disease.

Dr Pienaar said: "For the highest chance of recovery, treatments need to be focused and targeted but that requires a lot more research and understanding of exactly how Parkinson's operates and how our nerve systems work.

"Discovering that both cholinergic and dopaminergic neurons can be successfully targeted together is a big step forward.

"While this sort of gene therapy still needs to be tested on humans, our work can provide a solid platform for future bioengineering projects."

Lisa Wells, Head of CNS Discovery Applications at Invicro and co-author of this study commented: "It has been an exciting journey working with Dr Pienaar's team to combine the two technologies to offer us a powerful molecular approach to modify neuronal signaling and measure neurotransmitter release. We can support the clinical translation of this "molecular switch" into clinical utility through live imaging technology."

According to Parkinson's UK, around 145,000 people in the UK are diagnosed with the disease, which has three main symptoms -shaking, slowness of movement and muscle stiffness.

DURHAM, N.C. -- In chimpanzee society, males spend their entire lives in the group where they were born, cooperating to defend their territory, while females tend to move away. But some chimp females seem less willing to cut the apron strings.

New findings from researchers at Duke University and North Carolina State University show that female chimpanzees with high-ranking mothers are more likely to be homebodies.

The study suggests that the perks of having a powerful mom can make it worthwhile for some females to stay and reproduce in the same group where they grew up, despite the risks of inbreeding with male relatives.

For the research, appearing Jan. 20 in the journal Current Biology, primatologists Kara Walker and Anne Pusey analyzed 45 years of dawn-to-dusk observations for 31 female chimpanzees born in Gombe National Park in Tanzania, where Pusey began working with Jane Goodall in 1970.

Chimps are unusual among mammals in that daughters, not sons, typically pick up their roots at puberty and move away from their families. But in Gombe National Park, some chimpanzee females stay put instead of moving out.

Leaving home is hard, and no less so for a chimp. Immigrants risk a great deal -- leaving behind the familiar faces and comforts of home to strike out alone on a perilous journey, only to face multiple challenges upon arrival. Compared to stay-at-home females, those who leave are often attacked by resident females when they arrive in a new group. They also get a later start on motherhood.

So why do movers move away and stayers stay put? "I've always been intrigued by that question," said Pusey, professor emeritus of evolutionary anthropology at Duke. "It has driven my research for decades."

Differences between the sexes in migratory patterns are widespread in mammals and birds, Pusey said. She and colleagues first noticed the pattern at Gombe in the 1970s, but because female chimpanzees don't leave home until between the ages of 11 and 13, it would take years of observation to unravel the reasons behind it. Now, thanks to Pusey's efforts to compile and digitize the data and put it all in one database, researchers are starting to find answers.

In the study, the team found very little difference between females who left and those who stayed in terms of things like diet quality, crowding, or the number of unrelated males around when females reached maturity, which suggests they don't leave due to competition for food or lack of suitable mates.

It was only when the researchers looked more closely at the females' family members that the split began to reveal itself: specifically, they found that females with more brothers were more likely to leave -- presumably because they risk inbreeding if they stay.

Brothers and sisters from the same mom usually show little interest in each other, avoiding sex with close kin. But there are exceptions, said Walker, a research assistant professor of behavioral ecology at North Carolina State University. High-ranking males have been known to coerce their sisters into mating with them. For the chimpanzees at Gombe, only one of four known offspring of such close matings made it to adulthood.

"Breeding with a brother is a pretty costly mistake," Walker said.

The results confirm a decades-old hypothesis, that in many animals that live in groups, the hazards of inbreeding push one sex or the other to start their families elsewhere. But the study also points to a countervailing force that compels some female chimpanzees to stay put: mom. The researchers found that females with high-ranking moms on hand were more likely to stay rooted.

Yes, being the unwitting target of a brother's misdirected advances might be a pain, but for some, the risk might be offset by the benefits of having a built-in support system.

Living close to mom means she's able to provide help, such as by sharing prime foraging spots, the researchers say. And whereas females who move away enter their new groups at the bottom of the pecking order, females with powerful moms who choose to stay put benefit from their mother's social clout and "cut in line."

Pusey thinks a lot can be learned about the evolution of migratory patterns in humans by studying chimpanzees. Our species also typically sees young women more likely than young men to leave home for marriage.

Even in chimps, she says, "it's sometimes better for females to stay," which "suggests that the benefit of having mom around is pretty universal."

Limiting global warming to well below 2°C requires a decarbonized world by 2050 at the latest and a corresponding global transformation of the energy and land use systems of societies across the world. To achieve this goal of net-zero carbon by 2050 emissions need to be cut by half every decade from now on. An interdisciplinary team of researchers now explored tipping mechanisms that have the potential to spark rapid yet constructive societal changes towards climate stabilization and overall sustainability. These tipping elements and mechanisms could bring about a transition that is fast enough for meeting the targets of the Paris climate agreement.

Six elements emerge from an experts' survey and workshop

Published in the Proceedings of the National Academy of Sciences (PNAS), the scientists identify six socio-economic tipping elements and related interventions that could bring such a transition to a deep and rapid global decarbonization on its way.

"From the energy sector to financial markets to our cities - we were able to pin down social tipping elements and identify concrete interventions that might activate contagious processes of rapidly spreading technologies, behavioral patterns and social norms", lead author Ilona M. Otto, sociologist and economist from the Potsdam Institute for Climate Impact Research (PIK) explains. Drawing on an expert survey, an expert workshop and a thorough literature review, the social tipping interventions explored and proposed comprise the removal of fossil-fuels subsidies while incentivizing distributed energy generation; the construction of carbon-neutral cities; divestments from assets linked to fossil fuels; the exposure of the moral implications of fossil fuels; much improved climate education and engagement; and greenhouse gas emissions information disclosure.

"While this is neither a comprehensive nor a complete list, these results could help develop rapid socio-economic transformation pathways and explore narratives for a decarbonized future in 2050", Otto adds.

Divestment and climate-neutral power generation are the main short-term drivers

Researchers see the strongest short-term transformation potential in divestment decisions in financial markets as well as in energy production and storage systems, where the focus should be on using already existing greenhouse-gas neutral technologies. If financial flows are redirected away from companies in fossil industries and towards sustainable investments, a tipping point in the financial markets could be reached - for example, if national banks and insurance companies warn of the global consequences of so-called 'stranded assets'.

"This could trigger a positive avalanche effect," says the second lead author and physicist, Jonathan Donges of PIK's FutureLab on Earth Resilience in the Anthropocene. Similarly, the use and application of existing greenhouse gas-neutral technologies in power generation and energy efficiency could tip society towards sustainability. "The decisive factor for this adjustment process is the financial return. Our expert group believes that the critical mass that needs to be reached is the moment when climate-neutral power generation generates higher financial returns than fossil-based power generation," Donges said.

Climate protection as a socially recognized norm stabilizes the road to decarbonisation

It is essential that these relatively short-term tipping interventions such as divestment decisions are permanently supported and backed by changes in norms and values in society. "Awareness of global warming is high but social norms to fundamentally shift behavior are not. This is a mismatch that science alone cannot fix," says co-author Johan Rockström, Director of PIK. "For individuals to live a carbon free lifestyle must be made easy to succeed fast, but on the longer term a new social equilibrium is needed in which climate protection is recognised as a social norm, otherwise shocks on the financial markets or economic crises could destroy progress in decarbonisation."

"You can only beat nonlinearity with nonlinearity," says Hans-Joachim Schellnhuber, Director Emeritus of the PIK. "We can only contain the dynamic tipping processes in the Earth system that we have already initiated, such as the melting of the Greenland ice sheet, if we set social tipping processes in motion. This is all about the instigation of contagious dynamics within society, politics, and the economy, in which a new climate-friendly and sustainable stance spreads exponentially."

"An important current example of the potential of social dynamics is the Fridays for Future movement, which has provoked irritations in people's personal worldviews and may thus contribute to changing values and norms, opening political pathways for decarbonisation while developing the way we collectively think and act with regard to climate change," says co-author Wolfgang Lucht from PIK. "Such dynamics may lead to changes in politics and legislative measures, to climate-friendly transformations of infrastructure and to a reorientation of individual consumer decisions and lifestyles."

They might not yet speak in complete sentences, but 18-month-olds are savvy when it comes to deciding when and how to try.

According to a study from Arizona State University, the University of Washington and University of Toronto that has implications for how people learn, infants do not try things at random or simply mimic what they see adults doing. Instead, they combine information from their own firsthand experience and the experiences of other people to decide whether to persist in trying to solve a problem. The study will be published in Nature Human Behaviour on January 20.

"Persistence is important and plays a role in learning and life outcomes like school performance and emotional well-being," said Kelsey Lucca, assistant professor of psychology at ASU and first author on the paper. "But, it's not always a good idea to persist because effort is a limited resource, and deploying effort is metabolically costly, requiring time and energy. What truly drives learning is knowing when to try and what the best way to try is."

Nevertheless, the infant persisted

The research team devised an experiment that provided 18-month-old infants with social information and first-hand experience when solving a problem. Each of the 96 infants who participated in the experiment sat on their parent's lap at a table. Just out of reach on the table was a clear box with a toy inside. The box had a rope attached to it, and an experimenter seated at the table showed the infant how the rope could be pulled to bring the box, and the toy inside, within reach.

The infants saw one of three scenarios: the experimenter easily move the box, the experimenter struggle but ultimately succeed in moving the box, or the experimenter fail to move the box. In the first scenario, the experimenter pulled the rope and easily moved the box across the table on the first try. In the second scenario, the experimenter tried pulling on the rope five times and succeeded on the fifth try. The final scenario was the same as the second, except the experimenter was unsuccessful at moving the box and gave up after the fifth attempt.

Then it was the infants turn to try. Unbeknownst to the them, the experimenter had switched the box for one that was affixed to the table and impossible to move. The infants had three chances to move the box, and on each attempt the research team measured how much time they spent pulling the rope and how hard they pulled.

The infants who saw the experimenter fail to move the box or easily succeed at moving it spent progressively less time trying to move the box with each attempt. Only the infants who watched the experimenter struggle but then succeed persisted in trying to move the box. These infants spent about the same amount of time on each attempt.

"This finding suggests that the toddlers engaged in a sophisticated decision-making process, similar to how adults might create a list of pros and cons and use it to influence their choice," said Jessica Sommerville, professor of psychology at the University of Toronto and senior author on the paper. "The toddlers computed the utility, or usefulness, of trying to move the box by weighting the potential costs of what they had to lose - whether it was worth it keep pulling the rope - against what they had to gain in terms of the likelihood they could access the toy."

How hard the infants pulled on the rope was also related to what they watched the experimenter demonstrate. The infants who saw the experimenter fail to move the box did not pull the rope as hard as the two other groups who saw the experimenter succeed in moving the box. The infants who saw the experimenter easily move the box pulled the rope the hardest, and the infants who saw the experimenter struggle and succeed ramped up how hard they pulled on the rope with each attempt, suggesting both these two groups were confident they would be able to move the box by increasing their effort.

Infant inferences

After the three impossible trials, the research team again switched the box, this time for one that could move. On these trials, all three groups of infants successfully moved the box and accessed the toy inside.

The research team examined whether the infants showed help-seeking behaviors like pointing or reaching towards the box. The infants only sought help when they actually needed it, on the attempts when the box was affixed to the table and impossible to move. They did not ask for help on the trials when the box was moveable.

The infants who saw the experimenter easily move the box requested help more than the other two groups, which indicates that the infants also only sought help when they knew it would be useful.

"The infants who saw the experimenter easily move the box traded off trying for help seeking, suggesting that they realized the most adaptive strategy in that context was to get help from someone who can solve the problem," Lucca said. "The infants who saw the experimenter struggle but succeed needed the least amount of support to solve the task - suggesting that demonstrations of hard work and effort have carry over effects that impact infants' motivation in future tasks."

The team also assessed whether the infants' facial expressions showed positive or negative emotions while they tried to move the box. The infants who saw the experimenter easily move the box showed the most frustration, because their expectations for what was supposed to happen did not match their experience. These infants also required the most prompting to try and move the box on the trials when it was moveable.

"It seems intuitive that the experience of kids facing a challenge is inherently frustrating, but we found that the mismatch between expectations and experience is actually what is frustrating," Sommerville said. "Setting appropriate expectations for kids about difficulty and effort doesn't dissuade them, it lets them scale their expectations so when something is hard, they can choose to keep trying."

A new study in the journal Nature Sustainability overturns long-held interpretations of the role humans played in shaping the American landscape before European colonization. The findings give new insight into the rationale and approaches for managing some of the most biodiverse landscapes in the eastern U.S.

The study, led by archaeologists, ecologists, and paleoclimatologists at Harvard, Emerson College and elsewhere, focuses on the coast from Long Island to Cape Cod and the nearby islands of Nantucket, Martha's Vineyard, Block Island, and Naushon--areas that historically supported the greatest densities of Native people in New England and today are home to the highest concentrations of rare habitats in the region, including sandplain grasslands, heathlands, and pitch pine and scrub oak forests.

"For decades, there's been a growing popularization of the interpretation that, for millennia, Native people actively managed landscapes - clearing and burning forests, for example - to support horticulture, improve habitat for important plant and animal resources, and procure wood resources," says study co-author David Foster, Director of the Harvard Forest at Harvard University. This active management is said to have created an array of open-land habitats and enhanced regional biodiversity.

But, Foster says, the data reveal a new story. "Our data show a landscape that was dominated by intact, old-growth forests that were shaped largely by regional climate for thousands of years before European arrival."

Fires were uncommon, the study shows, and Native people foraged, hunted, and fished natural resources without actively clearing much land.

"Forest clearance and open grasslands and shrublands only appeared with widespread agriculture during the European colonial period, within the last few hundred years," says Wyatt Oswald, a professor at Emerson College and lead author of the study.

The authors say the findings transform thinking about how landscapes have been shaped in the past - and therefore how they should be managed in the future.

"Ancient Native people thrived under changing forest conditions not by intensively managing them but by adapting to them and the changing environment," notes Elizabeth Chilton, archaeologist, co-author of the study, and Dean of the Harpur College of Arts and Sciences at Binghamton University.

To reconstruct historical changes to the land, the research team combined archaeological records with more than two dozen intensive studies of vegetation, climate, and fire history spanning ten thousand years. They found that old-growth forests were predominant for millennia but are extremely uncommon today.

"Today, New England's species and habitat biodiversity are globally unique, and this research transforms our thinking and rationale for the best ways to maintain it," says Oswald. "It also points to the importance of historical research to help us interpret modern landscapes and conserve them effectively into the future."

The authors also note the unique role that colonial agriculture played in shaping landscapes and habitat. "European agriculture, especially the highly varied activity of sheep and cattle grazing, hay production, and orchard and vegetable cultivation in the 18th and 19th centuries, made it possible for open-land wildlife species and habitats that are now rare or endangered - such as the New England cottontail - to thrive," says Foster. Open-land species have declined dramatically as forests regrow on abandoned farmland, and housing and commercial development of both forests and farms have reduced their habitat.

Foster notes that the unique elements of biodiversity initiated through historical activities can be encouraged through analogous management practices today.

"Protected wildland reserves would preserve interior forest species that were abundant before European settlement," he says. "Lands managed through the diversified farming and forestry practices that created openlands and young forests during the colonial period would support another important suite of rare plants and animals."

For successful conservation models that leverage this historical perspective, the authors point to efforts by The Trustees of Reservations, the oldest land trust in the world, which manages more than 25,000 acres in Massachusetts embracing old and young forests, farms, and many cultural resources. The organization uses livestock grazing to keep lands open for birds like bobolinks and meadowlarks, which in turn supports local farmers and produces food for local communities.

Jocelyn Forbush, Executive Vice President for the Trustees, says, "Maintaining the legacy of our conserved openlands in Massachusetts is an important goal for The Trustees and we are increasingly looking to agricultural practices to yield a range of outcomes. In particular, we are employing grazing practices to support the habitats of our open and early successional lands in addition to the scenic and cultural landscapes that shape the character of our communities."

A scientific paper published in 1985 was the first to report a burgeoning hole in Earth's stratospheric ozone over Antarctica. Scientists determined the cause to be ozone-depleting substances - long-lived artificial halogen compounds. Although the ozone-destroying effects of these substances are now widely understood, there has been little research into their broader climate impacts.

A study published today in Nature Climate Change by researchers at Columbia University examines the greenhouse warming effects of ozone-depleting substances and finds that they caused about a third of all global warming from 1955 to 2005, and half of Arctic warming and sea ice loss during that period. They thus acted as a strong supplement to carbon dioxide, the most pervasive greenhouse gas; their effects have since started to fade, as they are no longer produced and slowly dissolve.

Ozone-depleting substances, or ODS, were developed in the 1920s and '30s and became popularly used as refrigerants, solvents and propellants. They are entirely manmade, and so did not exist in the atmosphere before this time. In the 1980s a hole in Earth's stratospheric ozone layer, which filters much of the harmful ultraviolet radiation from the sun, was discovered over Antarctica. Scientists quickly attributed it to ODS.

The world sprang into action, finalizing a global agreement to phase out ODS. The Montreal Protocol, as it is called, was signed in 1987 and entered into force in 1989. Due to the swift international reaction, atmospheric concentrations of most ODS peaked in the late 20th century and have been declining since. However, for at least 50 years, the climate impacts of ODS were extensive, as the new study reveals.

Scientists at Columbia's School of Engineering and Applied Science and the Lamont-Doherty Earth Observatory used climate models to understand the effects of ODS on Arctic climate. "We showed that ODS have affected the Arctic climate in a substantial way," said Lamont-Doherty researcher Michael Previdi. The scientists reached their conclusion using two very different climate models that are widely employed by the scientific community, both developed at the U.S. National Center for Atmospheric Research.

The results highlight the importance of the Montreal Protocol, which has been signed by nearly 200 countries, say the authors. "Climate mitigation is in action as we speak because these substances are decreasing in the atmosphere, thanks to the Montreal Protocol," said Lorenzo Polvani, lead author of the study and a professor in Columbia's Department of Applied Physics and Applied Mathematics. "In the coming decades, they will contribute less and less to global warming. It's a good-news story."

Killing and eating of potential competitors, also known as intraguild predation, is a rare event that occurs only in specific situations such as severe scarcity of food resources, resulting in the competition between predators.

A recent paper in the open-access journal Subterranean Biology examines the case of a wandering spider species (Enoploctenus cyclotorax) seen to prey upon assassin bugs (Zelurus diasi) in a limestone cave in Brazil.

Even though such type of ecological interaction is uncommon, it is potentially important since it may decrease the competition between apex predators and thus, affect their population dynamics. Zelurus and Enoploctenus are voracious predators with a wide distribution in caves and epigean environment. Both of them have similar diets. In normal conditions, spiders reject assassin bugs as potential prey, so intraguild predation cases occur only in very specific situations.

From the perspective of the participants, intraguild predation is a dangerous strategy because the prey is also a predator, armed and capable to kill. However, in caves, this could be a very useful behaviour since food resources are scarce and have low density.

"This may be an important factor, maintaining the species in that challenging environment", concludes lead author of the study Dr. Leopoldo Ferreira de Oliveira Bernardi.

The scientists suggest that probably prey scarcity has left little choice for spiders, and that's why they ended up using unconventional type of prey in their diet.

Projected ocean warming and acidification not only impacts the behaviour of individual species but also the wider marine ecosystems which are influenced by them, a new study shows.

Research published in Nature Climate Change shows that in warmer seawater with lower pH, a common clam - the peppery furrow shell (Scrobicularia plana) - makes considerable changes to its feeding habits.

Instead of relying predominantly on food from within the water column, it changed its behaviour to use its tube-like feeding siphon to scrape more of its food from the seafloor.

This in turn led to surface-dwelling invertebrates showing greater tolerance to warming and acidification, most likely due to the stimulatory effect of the clam's altered feeding on their microalgal food resources.

The study was conducted by researchers at Ghent University (Belgium), University of Plymouth (UK) and University of South Carolina (USA).

They say it demonstrates that changes in ocean conditions can significantly alter the interaction network among porewater nutrients, primary producers, herbivores and burrowing invertebrates.

They also highlight that mechanistic insights into non-lethal climate change effects are urgently needed to improve the understanding of ocean warming and acidification in predicted future ocean conditions.

This particular species of clam is one of the most common large burrowing bivalves along the northeastern Atlantic, Mediterranean and Baltic sea coastlines, where it is an important prey species for wading birds and affects other sediment fauna and biogeochemistry.

For the study, researchers used pressure sensors to test how the combined effects of experimental warming and acidification influence feeding behaviour, which is largely hidden from direct observation. They also analysed how the clam's presence mediated the combined warming and acidification effects on ecosystem interactions and population resilience among other species.

Dr Carl Van Colen, a researcher at Ghent University, led the study. He said: "This work demonstrates the importance of incorporating understanding about how species interact with others and their environment to better predict how individual populations will cope with climate change. The big advancement in this research came when we started to use pressure sensors to pick up small changes in sediment porewater hydraulics that we could link to the behaviour of the clams. By using this technology we were able to shed light into the 'hidden' life of organisms living burrowed in seafloor sediments."

Mark Briffa, Professor of Animal Behaviour at the University of Plymouth and one of the study's co-authors, added: "This shows how unexpected the effects of human impacts on our environment can be. If the behaviour of a given species changes as a result of ocean acidification and warming, what are the implications for other components of that community? Our study illustrates the importance of investigating the consequences of human impacts on the environment at multiple levels including how it affects the way animals behave."