Monday, November 23, 2020

COVID Shocks to Seafood Market

Research shows that typical seafood distribution in the United States dropped steeply at the start of the global pandemic.


Credit: UCSB/iStock


The United States’ seafood industry declined precipitously in the months following the emergence of the COVID-19 pandemic, and research shows that targeted federal assistance will be necessary to bring it back.

UC Santa Barbara aquaculture and fisheries professor Halley Froehlich and colleagues suspected as much early on in the pandemic, but for something as large and complex as the seafood industry, the trends were not so obvious. As a result, financial assistance in that direction has been slow.

“Seafood is part of the narrative that I would say doesn’t get as much attention as something like agriculture,” said Froehlich, an author of a study published in the journal Fish and Fisheries. “And that certainly appears to be the case when we’re looking at something like the CARES Act, the federal funding source specifically passed to provide economic relief in the U.S.”

That is, in large part, due to the fact that policymakers lack sufficient real-time data to see how the seafood industry is faring in the time of lockdowns and social distancing, said the study’s lead author, University of Vermont ecologist Easton White.

“One difficulty is that a lot of this data isn’t released until months and years later,” he said. From the boat to the table, data is generated that must be gathered and processed before it gets released, he explained.

The pandemic is a rapidly evolving situation and the seafood industry can’t afford to wait. So, to get a big-picture look at the early effects of COVID-19 on U.S. fisheries and seafood consumption, Froehlich, White and fellow fisheries data experts synthesized multiple sources from across the seafood supply chain, including some unconventional real-time data sets.

“We looked for different indicators of the effects of COVID on seafood and fisheries in general,” White said. In addition to federal fisheries reports and customs data, the researchers looked to news reports and Google search trends for seafood and seafood market foot traffic.

Lessons Learned
As had happened for virtually every industry at the start of the pandemic, the lockdowns and closures caused a huge drop in economic activity for the seafood sector, from which many still struggle to recover. Using data from January to September 2020, the researchers calculated a 40% decline in fresh seafood catches, a 37% decline in imports and a 43% drop in exports relative to the same time last year. These impacts are expected to reverberate across the globe, as the U.S. is one of the top exporters and importers of seafood.

Closer to home, demand from restaurants — the main driver of seafood spending in the U.S. — virtually disappeared as establishments locked down. Seafood market foot traffic declined steeply as well.

The effects were uneven across fisheries and aquaculture operations.

“Large-scale production systems that have large networks were able to pivot really fast,” Froehlich said. “And so if they couldn’t sell in one location, they were more easily able to sell to a different location. They felt the impacts, but not as much as the small scale fisheries that then had to depend on looking for local buyers.”

Frozen seafood products, according to the paper, “were generally less affected.”

One interesting development has been the uptick in seafood delivery and takeout, which has been picking up some — but not all — of the slack in restaurant demand.

“It’s unclear to us the level of substitution and what it means in the long term, especially how people are consuming seafood at home,” said Froehlich, who is interested in how this consumption pattern might influence the demand for certain species over time.

Because of COVID-19’s variable effects across the entire seafood industry, according to the researchers, future federal support should be aimed at locations and sub-sectors “most affected by the pandemic: fishery-dependent communities, processors and fisheries and aquaculture that focus on fresh products.”

“A lot of communities are dependent on fisheries,” White said. “There are fisheries for tourism, for livelihoods, and a lot of indigenous communities focus on fishing. And it’s not just fishing but also fish processing, all the different people that are involved. If you have COVID popping up just when you’re about to go fishing and make all the money you’re going to have for the year, now you can’t make any of that.”

The pandemic has highlighted some of the stress points in the U.S.’s seafood supply chain, the researchers said. Preserving a diversity of the sub-sectors within the seafood industry — for instance, small local operations as well as large fisheries — will keep the entire system resilient to shocks.

“If you have locally-sourced seafood, if you have aquaculture and fisheries, if you have small-scale and large-scale, this is a little more robust,” White said.

This study is the first to be produced from the wealth of data the researchers gathered. A parallel study will publish in the journal Marine Policy that examines how policy, particularly the new federal seafood acts and executive orders, can support more integrated management and diversification of the US seafood sector. The researchers hope the information will help guide the rebuilding of the flagging U.S. seafood industry to be more resilient to future shocks, including climate change impacts.

“As new mandates and legislation around fisheries and aquaculture are being rolled out during COVID-19 at the national and state levels, we have an opportunity to really think about what the actual targets and goals are. How do we build in more resilience now, instead of retroactively, when the system gets disrupted again,” Froehlich said. “Because it will.”

Research in this study was conducted also by Richard S. Cottrell at UCSB; Jessica A. Gephart at American University, Trevor A. Branch at University of Washington, Rahul Agrawal Bejarano at University of Michingan and Julia K. Baum at University of Victoria

The study is available at: https://onlinelibrary.wiley.com/doi/10.1111/faf.12525

Contacts and sources:
Sonia Fernandez
University of California Santa Barbara 



 





COVID-19 Cases Could Nearly Double to 20 Million before Biden Takes Office

President-elect Joe Biden has signaled that fighting the COVID-19 pandemic will be an immediate priority for his administration. He recently announced a coronavirus advisory board of infectious disease researchers and former public health advisers along with an updated strategy that will include increases in testing and contact tracing, as well as transparent communication.

But Inauguration Day is still two months away. The number of confirmed COVID-19 cases are likely to increase to 20 million by the end of January, nearly doubling the current level of 11.4 million cases, predicts a Washington University in St. Louis COVID-19 forecasting model.

The model, which accurately forecasted the rate of COVID-19 growth over the summer of 2020, was developed by Olin Business School’s Meng Liu, Raphael Thomadsen and Song Yao. Their paper presenting the model and its forecasts was published Nov. 23 by Scientific Reports.

“One of the key reasons for the increased accuracy of this model over other COVID-19 forecasts is that this model accounts for the fact that people live in interconnected social networks rather than interacting mostly with random groups of strangers,” said Thomadsen, professor of marketing. “This allows the model to forecast that growth will not continue at exponential rates for long periods of time, as classic COVID-19 forecasts predict.”

The evolution of COVID-19 depends on how much we, as a country, continue to social distance or return back to normal levels of interaction. This chart shows forecasted cases in the U.S. through the end of January 2021 based on our current social distancing levels, as well as less and more social distancing.

Credit: Washington University in St Louis


An interactive online version of the model also allows users to observe the impact different levels of social distancing will have on the spread of COVID-19. The current social distancing reflects an approximate 60% return to normalcy, as compared with the level of social distancing before the pandemic. If we continue, as a nation, at the current level of social distancing, the model forecasts that we are likely to reach 20 million cases before the end of January 2021.

“Even small increases in social distancing can have a large effect on the number of cases we observe in the next two and a half months,” Thomadsen said. “Going back to a 50% return to normalcy, which was the average level of distancing in early August, would likely result in 5 million fewer cases by the end of January.

“We could effectively squash out the COVID growth within a few weeks if we went back to the levels of social distancing we experienced in April,” he added.

However, the researchers caution that this is likely a conservative estimate due to increased testing and the upcoming holidays.

“In our model, we assume that only 10% of cases are ever diagnosed, meaning that we will start to hit saturation,” said Song Yao, associate professor of marketing and study co-author. “However, more recently, testing has increased, and probably more like 25% of cases are diagnosed. In that case, total COVID cases would increase beyond 20 million in the next few months unless we, as a society, engage in more social distancing.”

“The upcoming holiday seasons will present a great deal of uncertainty to the outlook of the pandemic as people travel more at the end of the year. This will likely make our forecast an optimistic one,” said Meng Liu, assistant professor of marketing and study co-author.




Contacts and sources:
Sara Savat
Washington University in St Louis


Publication: Forecasting the spread of COVID-19 under different reopening strategies
Meng Liu, Raphael Thomadsen & Song Yao
Scientific Reports volume 10, Article number: 20367 (2020) http://dx.doi.org/10.1038/s41598-020-77292-8




The Drug Aprotinin Inhibits Entry of SARS-CoV2 in Host Cells

In order for the SARS-CoV2 virus to enter host cells, its “spike” protein has to be cleaved by the cell's own enzymes - proteases. The protease inhibitor aprotinin can prevent cell infection, as scientists at Goethe University, the University of Kent and the Hannover Medical School have now discovered. An aprotinin aerosol is already approved in Russia for the treatment of influenza and could readily be tested for the treatment of COVID-19.

Credit: Goethe University Frankfurt

The surface of the SARS-CoV-2 virus is studded with spike proteins. The virus needs these in order to dock onto proteins (ACE2 receptors) on the surface of the host cell. Before this docking is possible, parts of the spike protein have to be cleaved by the host cell's enzymes - proteases.

In cell culture experiments with various cell types, the international scientific team led by Professor Jindrich Cinatl, Institute for Medical Virology at the University Hospital Frankfurt), Professor Martin Michaelis, and Dr Mark Wass (both University of Kent) demonstrated that the protease inhibitor aprotinin can inhibit virus replication by preventing SARS-CoV2 entry into host cells. Moreover, aproticin appears to compensate for a SARS-CoV2-induced reduction of endogenous protease inhibitors in virus-infected cells.

Influenza viruses require host cell proteases for cell entry in a similar way as coronaviruses. Hence, an aprotinin aerosol is already approved in Russia for the treatment of influenza.

Professor Jindrich Cinatl said: “Our findings show that aprotinin is effective against SARS-CoV2 in concentrations that can be achieved in patients. In aprotinin we have a drug candidate for the treatment of COVID-19 that is already approved for other indications and could readily be tested in patients. "








Contacts and sources:
Jindrich Cinatl
Goethe University Frankfurt

Publication: Denisa Bojkova, Marco Bechtel, Katie-May McLaughlin, Jake E. McGreig, Kevin Klann, Carla Bellinghausen, Gernot Rohde, Danny Jonigk, Peter Braubach, Sandra Ciesek, Christian Münch, Mark N. Wass, Martin Michaelis, Jindrich Cinatl jr . Aprotinin inhibits SARS-CoV-2 replication . Cells 2020, https://www.mdpi.com/2073-4409/9/11/2377





Features That Could Make Someone a Virus Super-Spreader



New research from the University of Central Florida has identified physiological features that could make people super-spreaders of viruses such as COVID-19.

Sneeze velocity for four different nose and mouth types is shown. A is open nasal passage with teeth, B is open nasal passage without teeth, C is blocked nasal passage without teeth, and D is blocked nasal passage with teeth.
Credit: UCF


In a study appearing this month in the journal Physics of Fluids, researchers in UCF’s Department of Mechanical and Aerospace Engineering used computer-generated models to numerically simulate sneezes in different types of people and determine associations between people’s physiological features and how far their sneeze droplets travel and linger in the air.

They found that people’s features, like a stopped-up nose or a full set of teeth, could increase their potential to spread viruses by affecting how far droplets travel when they sneeze.

According to the U.S. Centers for Disease Control and Prevention, the main way people are infected by the virus that causes COVID-19 is through exposure to respiratory droplets, such as from sneezes and coughs that are carrying infectious virus.

Knowing more about factors affecting how far these droplets travel can inform efforts to control their spread, says Michael Kinzel, an assistant professor with UCF’s Department of Mechanical Engineering and study co-author.

“This is the first study that aims to understand the underlying ‘why’ of how far sneezes travel,” Kinzel says. “We show that the human body has influencers, such as a complex duct system associated with the nasal flow that actually disrupts the jet from your mouth and prevents it from dispersing droplets far distances.”

For instance, when people have a clear nose, such as from blowing it into a tissue, the speed and distance sneeze droplets travel decrease, according to the study.

This is because a clear nose provides a path in addition to the mouth for the sneeze to exit. But when people’s noses are congested, the area that the sneeze can exit is restricted, thus causing sneeze droplets expelled from the mouth to increase in velocity.

Similarly, teeth also restrict the sneeze’s exit area and cause droplets to increase in velocity.

“Teeth create a narrowing effect in the jet that makes it stronger and more turbulent,” Kinzel says. “They actually appear to drive transmission. So, if you see someone without teeth, you can actually expect a weaker jet from the sneeze from them.”

To perform the study, the researchers used 3D modeling and numerical simulations to recreate four mouth and nose types: a person with teeth and a clear nose; a person with no teeth and a clear nose; a person with no teeth and a congested nose; and a person with teeth and a congested nose.

When they simulated sneezes in the different models, they found that the spray distance of droplets expelled when a person has a congested nose and a full set of teeth is about 60 percent greater than when they do not.

The results indicate that when someone keeps their nose clear, such as by blowing it into a tissue, that they could be reducing the distance their germs travel.

The researchers also simulated three types of saliva: thin, medium and thick.

They found that thinner saliva resulted in sneezes comprised of smaller droplets, which created a spray and stayed in the air longer than medium and thick saliva.

For instance, three seconds after a sneeze, when thick saliva was reaching the ground and thus diminishing its threat, the thinner saliva was still floating in the air as a potential disease transmitter.

The work ties back to the researchers’ project to create a COVID-19 cough drop that would give people thicker saliva to reduce the distance droplets from a sneeze or cough would travel, and thus decrease disease-transmission likelihood.

The findings yield novel insight into variability of exposure distance and indicate how physiological factors affect transmissibility rates, says Kareem Ahmed, an associate professor in UCF’s Department of Mechanical and Aerospace Engineering and study co-author.

“The results show exposure levels are highly dependent on the fluid dynamics that can vary depending on several human features,” Ahmed says. “Such features may be underlying factors driving superspreading events in the COVID-19 pandemic.”

The researchers say they hope to move the work toward clinical studies next to compare their simulation findings with those from real people from varied backgrounds.

Study co-authors were Douglas Fontes, a postdoctoral researcher with the Florida Space Institute and the study’s lead author, and Jonathan Reyes, a postdoctoral researcher in UCF’s Department of Mechanical and Aerospace Engineering.

Fontes says to advance the findings of the study, the research team wants to investigate the interactions between gas flow, mucus film and tissue structures within the upper respiratory tract during respiratory events.

“Numerical models and experimental techniques should work side by side to provide accurate predictions of the primary breakup inside the upper respiratory tract during those events,” he says.

“This research potentially will provide information for more accurate safety measures and solutions to reduce pathogen transmission, giving better conditions to deal with the usual diseases or with pandemics in the future,” he says.

The work was funded by the National Science Foundation.

Kinzel received his doctorate in aerospace engineering from Pennsylvania State University and joined UCF in 2018. In addition to being a member of UCF’s Department of Mechanical and Aerospace engineering, a part of UCF’s College of Engineering and Computer Science, he also works with UCF’s Center for Advanced Turbomachinery and Energy Research.

Ahmed is an associate professor in UCF’s Department of Mechanical and Aerospace Engineering, a faculty member of the Center for Advanced Turbomachinery and Energy Research, and the Florida Center for Advanced Aero-Propulsion. He served more than three years as a senior aero/thermo engineer at Pratt & Whitney military engines working on advanced engine programs and technologies. He also served as a faculty member at Old Dominion University and Florida State University. At UCF, he is leading research in propulsion and energy with applications for power generation and gas-turbine engines, propulsion-jet engines, hypersonics and fire safety, as well as research related to supernova science and COVID-19 transmission control. He earned his doctoral degree in mechanical engineering from the State University of New York at Buffalo. He is an American Institute of Aeronautics and Astronautics associate fellow and a U.S. Air Force Research Laboratory and Office of Naval Research faculty fellow.






Contacts and sources:
Robert Wells
University of Central Florida

Publication: A study of fluid dynamics and human physiology factors driving droplet dispersion from a human sneeze. D. Fontes, J. Reyes, K. Ahmed, M. Kinzel. Physics of Fluids, 2020; 32 (11): 111904 DOI: 10.1063/5.0032006




Very Hungry And Angry, Caterpillars Head-Butt To Get What They Want

Inspired by his own butterfly garden at home, a Florida Atlantic University neuroscientist got a unique look at how monarch butterfly (Danaus plexippus) caterpillars behave when food is scarce. The results look something like a combination of boxing and “bumper” cars. With less access to their favorite food – milkweed – they go from docile to domineering, aggressively head-butting, lunging and knocking aside other caterpillars to ensure their own survival. And, they are most aggressive right before the final stages of their metamorphosis. A lack of nutrition during larval stages has been shown to delay larval development as well as reduce adult body size, reproductive performance and lifespan.

The less food, the more likely caterpillars were to try to head-butt each other out of the way to get their fill, lunging and knocking aside other caterpillars to ensure their own survival. And, they are most aggressive right before the final stages of their metamorphosis.

Credit: Florida Atlantic University

“Aggression is common in insects, including fruit flies, where single-pheromone receptors or single genes have been shown to trigger their aggression,” said Alex Keene, Ph.D., lead author and a professor of biological sciences, FAU’s Charles E. Schmidt College of Science. “I decided to investigate monarch caterpillars because I was intrigued by their combative behavior, which I observed first-hand in my own garden. They are large and easily recognizable compared to many other insects. These are charismatic animals that everyone loves, and there’s a growing appreciation for their potential to tell us about how the brain controls behavior.”

For the study, published in the journal iScience, researchers faced a number of challenges maintaining a population of monarchs while trying to model resource limitation. To encounter these challenges, Keene and his team built an open milkweed garden behind their Boca Raton-based lab and let nature do the work of collecting caterpillars. Back in the lab, the researchers placed caterpillars into groups with different amounts of milkweed. The results were clear – the less food, the more likely caterpillars were to try to head-butt each other out of the way to get their fill.

The process of getting to that result also was challenging. The researchers had difficulty breeding the monarchs in the lab, and found that almost every nursery sells their milkweed with pesticides. That’s why they ended up growing their own milkweed.

To examine whether caterpillars display aggressive behavior, Keene and collaborators quantified the presence of aggressive lunges under a number of conditions, as well as the effect of attacks on target conspecifics. Monarch caterpillars predominantly feed on milkweed and often strip entire plants bare of leaves over a two-week period. In many locations, milkweed is only available for part of the year, placing a significant constraint on monarch development. Monarchs also impact the milkweed plants they consume – at their largest and hungriest phase, a single caterpillar may devour an entire milkweed leaf in under five minutes.

“If you compare a monarch caterpillar to a fruit fly where there are lot of larvae on one piece of rotting fruit, you’ll find that they feed socially with little evidence of territoriality,” said Keene. “But each of these caterpillars will at some point in their developmental cycle encounter resource limitation because they can strip an entire milkweed of leaves.”

Credit: Florida Atlantic University

While observing the caterpillars, researchers noticed that the monarch’s tentacles, large mechanosensory appendages, were not utilized when they were being combative. This finding suggests that alternative sensory modalities, such as pheromonal, olfactory or tactile cues that are independent of the tentacles initiate aggression. The researchers believe that aggression induced by limited food availability in monarch caterpillars are likely present in many different species throughout the animal kingdom.

“While our research showed that the caterpillars respond aggressively to limited food, we still hope to learn more about what drives this response in their brains, which is important for learning more about how these responses work outside the lab,” said Keene. “One of the fundamental problems with work like this is that we’re testing animals in a very derived setting. And that’s not what brains evolved to do. So now that we have this invertebrate model in a relatively controlled setting, but doing an ecologically relevant behavior, that becomes important in terms of looking at the mechanism and function of this behavior in more complex organisms.”

Beyond the study of aggression in caterpillars, monarchs present an emerging model for studying the molecular mechanisms underlying behavior and set the stage for future investigations into the neuroethology of aggression in this system.

Study co-authors are Joseph Collie, Odelvys Granela, and Elizabeth B. Brown, Ph.D., all within FAU’s Department of Biological Sciences and the program in neurogenetics.

The research was supported by the National Science Foundation.



Contacts and sources: 
Gisele Galoustian
Florida Atlantic University


Publication: Aggression is induced by resource limitation in the monarch caterpillar.
Keene et al. iScience, 2020 DOI: 10.1016/j.isci.2020.101791






Giant Poisonous Rats So Lethal They Can Kill Elephants and Humans

The African crested rat (Lophiomys imhausi) is hardly the continent’s most fearsome-looking creature—the rabbit-sized rodent resembles a gray puffball crossed with a skunk—yet its fur is packed with a poison so lethal it can fell an elephant and just a few milligrams can kill a human
Credit: University of Utah 

In a Journal of Mammology paper published today, Smithsonian Conservation Biology Institute, University of Utah and National Museums of Kenya researchers found the African crested rat is the only mammal known to sequester plant toxins for chemical defense and uncovered an unexpected social life—the rats appear to be monogamous and may even form small family units with their offspring.

“It’s considered a ‘black box’ of a rodent,” said Sara Weinstein, lead author and Smithsonian-Mpala postdoctoral fellow and postdoctoral researcher at the University of Utah. “We initially wanted to confirm the toxin sequestration behavior was real and along the way discovered something completely unknown about social behavior. Our findings have conservation implications for this mysterious and elusive rat.”


An African crested rat is a rabbit-sized rodent that is the only known mammal to sequester plant toxins as a chemical defense 



Credit: Stephanie Higgins


People in East Africa have long suspected the rat to be poisonous. A 2011 paper proposed these large rodents sequester toxins from the poison arrow tree (Acokanthera schimperi). A source of traditional arrow poisons, Acokanthera contains cardenolides, compounds similar to those found in monarch butterflies, cane toads and some human heart medications. Cardenolides, particularly the ones in Acokanthera, are highly toxic to most animals.

“The initial 2011 study observed this behavior in only a single individual. A main goal of our study was to determine how common this exceptional behavior was,” said co-author Denise Dearing from the University of Utah.

When threatened, the African crested rat lives up to its name and erects a crest of hair on its back to reveal a warning on its flanks—black and white stripes running from neck-to-tail on each side of its body. The 2011 study hypothesized that the rats chew the Acokanthera bark and lick the plant toxins into specialized hairs at the center of these stripes.

In the new study, researchers trapped 25 African crested rats, the largest sample size of the species ever trapped. Using motion-activated cameras, they documented nearly 1,000 hours of rat behavior. For the first time, they recorded multiple rats sequestering Acokanthera toxins and discovered many traits that suggest they are social, and likely monogamous.

“Everyone thought it was a solitary animal. I’ve been researching this rat for more than ten years, so you would expect there to be fewer surprises,” said Bernard Agwanda, curator of Mammals at the Museums of Kenya, co-author of this study and the 2011 paper. “This can carry over into conservation policy.”

A rich social life

As a postdoctoral fellow at the Mpala Research Centre, Weinstein first searched for the rats with camera traps, but found that they rarely triggered the cameras. Weinstein was then joined by Katrina Nyawira, the paper’s second author and now a graduate student at Oxford Brookes University. Together, they spent months experimenting with live traps to capture the elusive rodents.

“We talked to rangers and ranchers to ask whether they’d seen anything.” said Nyawira. Eventually they figured out that loading the traps with smelly foods like fish, peanut butter and vanilla, did the trick. “Out of 30 traps, we finally got two animals. That was a win. This thing is really rare.”


Sara B. Weinstein (left), Katrina Nyawira (right) stand in front of Acokanthera schimperi, also known as the poison arrow tree. 


Credit:: Stephanie Higgins


Those two animals changed the course of the study. They first caught an individual female, then caught a male at the same site two days later.

“We put these two rats together in the enclosure and they started purring and grooming each other. Which was a big surprise, since everyone we talked to thought that they were solitary,” Weinstein said. “I realized that we had a chance to study their social interactions.”

Weinstein and Nyawira transformed an abandoned cow shed into a research station, constructing stalls equipped with ladders and nest boxes to simulate their habitat in tree cavities. They placed cameras in strategic spots of each pen and then analyzed every second of their footage, tracking the total activity, movement and feeding behavior. The aim was to build a baseline of normal behavior before testing whether behavior changed after the rats chewed the toxin cardenolides from the poison arrow tree.

“They’re herbivores, essentially rat-shaped little cows,” Weinstein said. “They spend a lot of time eating, but we also see them walk around, mate, groom, climb up the walls, sleep in the nest box.”

The footage and behavioral observations strongly support a monogamous lifestyle. They share many of the traits common among monogamous animals: large size, a long life span and a slow reproductive rate. Additionally, the researchers trapped a few large juveniles in the same location as adult pairs, suggesting that offspring spend an extended period of time with their parents. In the pens, the paired rats spent more than half of their time near each other, and frequently followed each other around. The researchers also recorded special squeaks, purrs and other communicative noises making up a wide vocal repertoire. Further behavioral studies and field observation would uncover more insights into their reproductive and family life.

A close up of a branch from Acokanthera schimperi. 



Credit: Sara B. Weinstein



After the researchers established a baseline of behavior, they offered rats branches from the poison arrow tree. Although rats did not sequester every time the plant was offered, 10 rats did at least once. They chewed it, mixed it with spit, and licked and chewed it into their specialized hairs. Exposure to the Acokanthera toxins did not alter rat behavior, and neither did eating milkweed, the same cardenolide-enriched plant used as chemical defense by monarch butterflies. Combined, these observations suggest that crested rats are uniquely resistant to these toxins.

“Most people think that it was a myth because of the potency of the tree,” said Nyawira. “But we caught it on video! It was very crazy.”

The rats were selective about using Acokanthera cardenolides, suggesting that rats may be picky about their toxin source, or that anointed toxins remain potent on the fur a long time, just like traditional arrow poisons from the same source.

African crested rat conservation

The African crested rat is listed as IUCN species of least concern, but there’s little actual data on the animals. Agwanda has studied African crested rats for more than a decade—and sees indications that they’re in trouble.

“We don’t have accurate numbers, but we have inferences. There was a time in Nairobi when cars would hit them and there was roadkill everywhere,” said Agwanda, who continues to monitor the populations. “Now encountering them is difficult. Our trapping rate is low. Their population is declining.”

The research team is planning future studies to better understand their physiology and behavior. “We are particularly interested in exploring the genetic mechanisms that allow the crested rats and their parasites to withstand the toxic cardenolides” said co-author Jesús Maldonado of the Smithsonian Conservation Biology Institute and Weinstein’s Smithsonian-Mpala Postdoctoral fellowship co-advisor.

“We are looking at a broad range of questions influenced by habitat change. Humans have cleared forests to make farms and roads. We need to understand how that impacts their survival,” Agwanda said. Additionally, Agwanda is building an exhibit at the Museums of Kenya to raise awareness about this unique poisonous animal.

Microscopic image of the specialized hairs that the African crested rat anoints with poison from Acokanthera schimperi 



PHOTO CREDIT: Sara B. Weinstein


About the Smithsonian’s National Zoo and Conservation Biology Institute

The Smithsonian’s National Zoo and Conservation Biology Institute leads the Smithsonian’s global effort to save species, better understand ecosystems and train future generations of conservationists. As Washington, D.C.’s favorite destination for families, the Zoo connects visitors to amazing animals and the people working to save them. In Front Royal, Virginia, across the United States and in more than 30 countries worldwide, Smithsonian Conservation Biology Institute scientists and animal care experts tackle some of today’s most complex conservation challenges by applying and sharing what they learn about animal behavior and reproduction, ecology, genetics, migration and conservation sustainability to save wildlife and habitats. Follow the Zoo on Facebook, Twitter and Instagram.

About the National Museums of Kenya
National Museums of Kenya (NMK) is a state corporation established by an Act of Parliament, the Museums and Heritage Act 2006. NMK is a multi-disciplinary institution whose role is to collect, preserve, study, document and present Kenya’s past and present cultural and natural heritage. This is for the purposes of enhancing knowledge, appreciation, respect and sustainable utilization of these resources for the benefit of Kenya and the world, for now and posterity. NMK’s mutual concern for the welfare of mankind and the conservation of the biological diversity of the East African region and that of the entire planet demands success in such efforts. In addition, NMK manages many Regional Museums, Sites and Monuments of national and international importance alongside priceless collections of Kenya’s living cultural and natural heritage. As an institution that must respond to the growing needs of the society, NMK is striving to contribute in a unique way to the task of national development.


Contacts and sources:
Lisa Potter
University of Utah



Publication: The secret social lives of African crested rats, Lophiomys imhausi.
Sara B Weinstein, Katrina Nyawira Malanga, Bernard Agwanda, Jesús E Maldonado, M Denise Dearing. Journal of Mammalogy, 2020 DOI: 10.1093/jmammal/gyaa127



Middle Stone Age Populations Repeatedly Occupied West African Coast



Excavations at Tiémassas, Senegal, indicate roughly 40,000 years of behavioural continuity, in contrast to other African regions over this period
 

In a study published in the Journal of Archaeological Science Reports, researchers from the Université Cheikh Anta Diop de Dakar, Senegal, the Max Planck Institute for the Science of Human History (MPI-SHH), and the University of Sheffield, reveal evidence of Middle Stone Age occupations of the West African coast. Ranging from 62 to 25 thousand years ago, the largest well-dated assemblages from the region clearly document technological continuity across almost 40,000 years in West Africa.


Lead author Khady Niang exploring the interface of forest, savannah and mangrove habitats close to Tiémassas

Credit: © J. Blinkhorn

Although coastlines have widely been proposed as potential corridors of past migration, the occupation of Africa’s tropical coasts during the Stone Age is poorly known, particularly in contrast to the temperate coasts of northern and southern Africa. Recent studies in eastern Africa have begun to resolve this, detailing dynamic behavioural changes near the coast of Kenya during the last glacial phase, but studies of Stone Age occupations along western Africa’s coasts are still lacking.

In recent years, anthropological research has begun to investigate the relationship between demographic diversity and patterns of behavioural change. A range of genetic and palaeoanthropological studies have begun to highlight the considerable demographic diversity present in West Africa in the recent past, but archaeological studies of Stone Age sites are still needed to understand how this diversity relates to patterns of behaviour shown in the archaeological record.

"There are plenty of surface sites that have demonstrated the wealth of Stone Age archaeology in West Africa," says Jimbob Blinkhorn of MPI-SHH, "but to characterise patterns of changing behaviour, we need large, excavated stone tool assemblages that we can clearly date to specific periods."


The excavation site at Tiémassas, which preserves evidence for Middle Stone Age occupations spanning 62-25 thousand years ago

Credit: © K. Niang

Tiémassas is a Stone Age site with a notable history of research, including surface surveys and early excavations in the mid-20th century, but the lack of systematic study meant it was mired in controversy.

"In the past, Tiémassas has been described as a Middle Stone Age, Later Stone Age or Neolithic site, and resolving between these alternatives has important implications for our understanding of behaviour at the site," says lead author Khady Niang of Université Cheikh Anta Diop de Dakar. "We've reviewed previously collected material from the site, conducted new excavations and analysis of stone tools and combined this with dating studies that make Tiémassas a benchmark example of the Middle Stone Age of West Africa."

Previous research by the team dated a Middle Stone Age occupation at Tiémassas to 45 thousand years ago. The new research extends the timeframe of occupations at the site, with further stone tool assemblages recovered dating to 62 thousand and 25 thousand years ago. Critically, these stone tool assemblages contain technologically distinct types that help to characterise the nature of stone tool production during each occupation phase.



A Levallois core recovered from excavations at Tiémassas, part of a common, persistent suite of stone tool technologies employed at the site between 62-25 thousand years ago[less]

Credit: © K. Niang

"The Middle Stone Age occupants of Tiémassas employed two distinct technologies - centripetal Levallois and discoidal reduction systems," says Niang. "What is really notable is that the stone tool assemblages are really consistent with one another and form a pattern we can match up with the results of earlier excavations too. Pulled together, the site tells a clear story of startling technological continuity for nearly 40 thousand years."

The results of this new research at Tiémassas consolidate the sparse record of Middle Stone Age occupations of West Africa. Yet, the site’s location is distinct from others dated to the Middle Stone Age in the region as it is located close to the coast and at the interface of three ecozones: savannahs, forests and mangroves.

"Our new work at Tiémassas offers a neat comparison to recent work on coastal occupations in eastern Africa. They span roughly the same timeframe, have similar ecological characteristics, and are found along tropical coasts," says Blinkhorn. "But the continuity in behaviour we see at Tiémassas stands in stark contrast to the technological changes observed in eastern Africa, and this reflects a similar pattern seen in genetic and palaeoanthropological studies of enduring population structure in West Africa."

As director of fieldwork for the ‘Lise Meitner’ Pan-African Evolution research group’s aWARE project, Blinkhorn is conducting research in Senegal, Ivory Coast, Benin, and Nigeria, looking for connections between the environments of the past and recent human evolution.



Contacts and sources:
Jimbob Blinkhorn
Max Planck Institute for the Science of Human History



Publication: The Middle Stone Age occupations of Tiémassas, coastal West Africa, between 62-25 thousand years ago
Khady Niang, James Blinkhorn, Matar Ndiaye, Mark Bateman, Birame Seck, Gora Sawaré
Journal of Archaeological Science: Reports http://dx.doi.org/10.1016/j.jasrep.2020.102658
Source

Geology at Mars’ Equator Points to Ancient Megaflood



Floods of unimaginable magnitude once washed through Gale Crater on Mars’ equator around 4 billion years ago – a finding that hints at the possibility that life may have existed there, according to data collected by NASA’s Curiosity rover and analyzed in joint project by scientists from Jackson State University, Cornell, the Jet Propulsion Laboratory and the University of Hawaii.

This composite, false-color image of Mount Sharp inside Gale crater on Mars shows geologists a changing planetary environment. On Mars, the sky is not blue, but the image was made to resemble Earth so that scientists could distinguish stratification layers.


Credit: NASA/JPL
 
The research, “Deposits from Giant Floods in Gale Crater and Their Implications for the Climate of Early Mars,” was published Nov. 5 in Nature Scientific Reports.

The raging megaflood – likely touched off by the heat of a meteoritic impact, which unleashed ice stored on the Martian surface – set up gigantic ripples that are tell-tale geologic structures familiar to scientists on Earth.

“We identified megafloods for the first time using detailed sedimentological data observed by the rover Curiosity,” said co-author Alberto G. Fairén, a visiting astrobiologist in the College of Arts and Sciences. “Deposits left behind by megafloods had not been previously identified with orbiter data.”

As is the case on Earth, geological features including the work of water and wind have been frozen in time on Mars for about 4 billion years. These features convey processes that shaped the surface of both planets in the past.

This case includes the occurrence of giant wave-shaped features in sedimentary layers of Gale crater, often called “megaripples” or antidunes that are about 30-feet high and spaced about 450 feet apart, according to lead author Ezat Heydari, a professor of physics at Jackson State University.

The antidunes are indicative of flowing megafloods at the bottom of Mars’ Gale Crater about 4 billion years ago, which are identical to the features formed by melting ice on Earth about 2 million years ago, Heydari said.

The most likely cause of the Mars flooding was the melting of ice from heat generated by a large impact, which released carbon dioxide and methane from the planet’s frozen reservoirs. The water vapor and release of gases combined to produce a short period of warm and wet conditions on the red planet.

Condensation formed water vapor clouds, which in turn created torrential rain, possibly planetwide. That water entered Gale Crater, then combined with water coming down from Mount Sharp (in Gale Crater) to produce gigantic flash floods that deposited the gravel ridges in the Hummocky Plains Unit and the ridge-and-trough band formations in the Striated Unit.

The Curiosity rover science team has already established that Gale Crater once had persistent lakes and streams in the ancient past. These long-lived bodies of water are good indicators that the crater, as well as Mount Sharp within it, were capable of supporting microbial life.

“Early Mars was an extremely active planet from a geological point of view,” Fairén said. “The planet had the conditions needed to support the presence of liquid water on the surface – and on Earth, where there’s water, there’s life.

“So early Mars was a habitable planet,” he said. “Was it inhabited? That’s a question that the next rover Perseverance … will help to answer.”

Perseverance, which launched from Cape Canaveral on July 30, is scheduled to reach Mars on Feb. 18, 2021.

Joining Fairén and Heydari on the paper are Jeffrey F. Schroeder, Fred J. Calef, Jason Van Beek and Timothy J. Parker, of NASA’s Jet Propulsion Laboratory; and Scott K. Rowland, University of Hawaii.

Data and funding were provided by NASA, Malin Space Science Systems, the Jet Propulsion Laboratory and the European Research Council.




Contacts and sources:
Blaine Friedlander
Cornell University
 




Publication: Deposits from giant floods in Gale crater and their implications for the climate of early Mars. E. Heydari, J. F. Schroeder, F. J. Calef, J. Van Beek, S. K. Rowland, T. J. Parker, A. G. Fairén.  Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-75665-7




Saturday, November 21, 2020

Water Has Multiple Liquid States Proved


Water is a ubiquitous liquid with many highly unique properties. The way it responds to changes in pressure and temperature can be completely different from other liquids that we know, and these properties are essential to many practical applications and particularly to life as we know it

What causes these anomalies has long been a source of scientific inspiration with various theoretical explanations, but now an international team of researchers, which includes Nicolas Giovambattista, a professor at The Graduate Center, CUNY and chair for the Department of Physics at Brooklyn College, has proved that water can exist in two different liquid states -- a finding that can explain many of water's anomalous properties. Their research appears in a paper published in the November 20 issue of the journal Science. 

The above graphic offers a conceptual view of how water can exist in two liquid states separated by a thin interface. The bottom liquid is more dense than the one on top, because it is composed of water molecules that are more cosely packed. 
Credit:  Jerker Lokrantz and Anders Nilsson


The possibility that water could exist in two different liquid states was proposed approximately 30 years ago, based on results obtained from computer simulations," Giovambattista said. "This counterintuitive hypothesis has been one of the most important questions in the chemistry and physics of water, and a controversial scenario since its beginnings. This is because experiments that can access the two liquid states in water have been very challenging due to the apparently unavoidable ice formation at the conditions where the two liquids should exist."

The usual "liquid" state of water that we are all familiar with corresponds to liquid water at normal temperatures (approximately 25 centigrade). However, the paper shows that water at low temperatures (approximately -63 centigrade) exists in two different liquid states, a low-density liquid at low pressures and a high-density liquid at high pressures. These two liquids have noticeably different properties and differ by 20% in density. The results imply that at appropriate conditions, water should exist as two immiscible liquids separated by a thin interface similar to the coexistence of oil and water.

Because water is one of the most important substances on Earth -- the solvent of life as we know it -- its phase behavior plays a fundamental role in different fields, including biochemistry, climate, cryopreservation, cryobiology, material science, and in many industrial processes where water acts as a solvent, product, reactant, or impurity. It follows that unusual characteristics in the phase behavior of water, such as the presence of two liquid states, can affect numerous scientific and engineering applications.

"It remains an open question how the presence of two liquids may affect the behavior of aqueous solutions in general, and in particular, how the two liquids may affect biomolecules in aqueous environments," Giovambattista said. "This motivates further studies in the search for potential applications."

Giovambattista is a member of the Physics and Chemistry Ph.D. programs at The Graduate Center of The City University of New York (CUNY).

The international team, led by Anders Nilsson, professor of chemical physics at Stockholm University, used complex experiments and computer simulations to prove this theory. The experiments, described as "science-fiction-like" by Giovambattista, were performed by colleagues at Stockholm University in Sweden, POSTECH University in Korea, PAL-XFEL in Korea, and SLAC national accelerator laboratory in California. The computer simulations were performed by Giovambattista and Peter H. Poole, professor at St. Francis Xavier University in Canada. The computer simulations played an important role in the interpretation of the experiments since these experiments are extremely complex and some observables are not accessible during the experiments.




Contacts and sources:
Shawn Rhea
The Graduate Center of The City University of New York

 





More than 1.1 Million Deaths Among Medicare Recipients Due to High Cost of Drugs

More than 1.1 million Medicare patients could die over the next decade because they cannot afford to pay for their prescription medications, according to a new study released today by the West Health Policy Center, a nonprofit and nonpartisan policy research group and Xcenda, the research arm of the drug distributor AmerisourceBergen.

If current drug pricing trends continue, researchers estimate cost-related non-adherence to drug therapy will result in the premature deaths of 112,000 beneficiaries a year, making it a leading cause of death in the U.S., ahead of diabetes, influenza, pneumonia, and kidney disease. Millions more will suffer worsening health conditions and run up medical expenses that will cost Medicare an additional $177.4 billion by 2030 or $18 billion a year for the next 10 years.


Credit: Tbel Abuseridze

Researchers also modeled what would happen if Medicare was allowed to bring down drug prices for its beneficiaries through direct negotiation with drug companies, as described in H.R. 3, the Elijah E. Cummings Lower Drug Costs Now Act, passed by the U.S. House of Representatives last year. They found Medicare negotiation could result in 94,000 fewer deaths annually. Additionally, the model found that the policy would reduce Medicare spending by $475.9 billion by 2030.

"One of the biggest contributors to poor health, hospital admissions, higher healthcare costs and preventable death is patients failing to take their medications as prescribed," said Timothy Lash, President, West Health Policy Center. "Cost-related nonadherence is a significant and growing issue that is direct result of runaway drug prices and a failure to implement policies and regulations that make drugs more affordable."

The price of prescription medications has skyrocketed in recent years. Between 2007 and 2018, list prices for branded pharmaceutical products increased by 159% and there are few signs of it slowing. According to the Centers for Medicare & Medicaid Services (CMS), spending on prescription drugs will grow faster than any other major medical good or service over the next several years.

Under Medicare, beneficiaries must pay 25% of the cost of generic and brand-name medications. For many people with multiple chronic conditions, this could add up to thousands of dollars a year in out-of-pocket costs.

"The costs of doing nothing about high drug prices are too high especially when policy changes such as allowing Medicare to negotiate drug prices would result in saving millions of lives and billions of dollars," said Sean Dickson, Director of Health Policy at West Health Policy Center and Chair of the Council for Informed Drug Spending Analysis (CIDSA), an independent group of experts on drug spending from leading academic institutions.

For the study, researchers developed a 10-year model representative of the majority of Medicare beneficiaries with chronic conditions. The model allows users to estimate how different levels of price reductions would lower the number of premature deaths and decrease Medicare spending on a sliding scale. The interactive tool and the complete technical report can be found on the CIDSA website.
 





Contacts and sources:
Aimee Brierly 
West Health Policy Center and West Health











Hyperbaric Oxygen Treatments Halt Aging of Blood Cells and Reverse Aging Process





A new study from Tel Aviv University (TAU) and the Shamir Medical Center in Israel indicates that hyperbaric oxygen treatments (HBOT) in healthy aging adults can stop the aging of blood cells and reverse the aging process. In the biological sense, the adults’ blood cells actually grow younger as the treatments progress.



Credit:(TAU


The researchers found that a unique protocol of treatments with high-pressure oxygen in a pressure chamber can reverse two major processes associated with aging and its illnesses: the shortening of telomeres (protective regions located at both ends of every chromosome) and the accumulation of old and malfunctioning cells in the body. Focusing on immune cells containing DNA obtained from the participants’ blood, the study discovered a lengthening of up to 38% of the telomeres, as well as a decrease of up to 37% in the presence of senescent cells.

The study was led by Professor Shai Efrati of the Sackler School of Medicine and the Sagol School of Neuroscience at TAU and Founder and Director of the Sagol Center of Hyperbaric Medicine at the Shamir Medical Center; and Dr. Amir Hadanny, Chief Medical Research Officer of the Sagol Center for Hyperbaric Medicine and Research at the Shamir Medical Center. The clinical trial was conducted as part of a comprehensive Israeli research program that targets aging as a reversible condition.

The paper was published in Aging on November 18, 2020.

“For many years our team has been engaged in hyperbaric research and therapy – treatments based on protocols of exposure to high-pressure oxygen at various concentrations inside a pressure chamber,” Professor Efrati explains. “Our achievements over the years included the improvement of brain functions damaged by age, stroke or brain injury.

“In the current study we wished to examine the impact of HBOT on healthy and independent aging adults, and to discover whether such treatments can slow down, stop or even reverse the normal aging process at the cellular level.”

The researchers exposed 35 healthy individuals aged 64 or over to a series of 60 hyperbaric sessions over a period of 90 days. Each participant provided blood samples before, during and at the end of the treatments as well as some time after the series of treatments concluded. The researchers then analyzed various immune cells in the blood and compared the results.

The findings indicated that the treatments actually reversed the aging process in two of its major aspects: The telomeres at the ends of the chromosomes grew longer instead of shorter, at a rate of 20%-38% for the different cell types; and the percentage of senescent cells in the overall cell population was reduced significantly – by 11%-37% depending on cell type.

“Today telomere shortening is considered the ‘Holy Grail’ of the biology of aging,” Professor Efrati says. “Researchers around the world are trying to develop pharmacological and environmental interventions that enable telomere elongation. Our HBOT protocol was able to achieve this, proving that the aging process can in fact be reversed at the basic cellular-molecular level.”

“Until now, interventions such as lifestyle modifications and intense exercise were shown to have some inhibiting effect on telomere shortening,” Dr. Hadanny adds. “But in our study, only three months of HBOT were able to elongate telomeres at rates far beyond any currently available interventions or lifestyle modifications. With this pioneering study, we have opened a door for further research on the cellular impact of HBOT and its potential for reversing the aging process.”

The research paper is available at the journal’s web site here.






Contacts and sources:
George Hunka
American Friends of Tel Aviv University (TAU)



Publication: Hyperbaric oxygen therapy increases telomere length and decreases immunosenescence in isolated blood cells : a prospective trial http://dx.doi.org/10.18632/aging.202188

Showing Robots How to Drive a Car...In Just a Few Easy Lessons



USC researchers have developed a method that could allow robots to learn new tasks, like setting a table or driving a car, from observing a small number of demonstrations.

A robot could learn from watching demonstrations by a human

Credit: iStock 

Imagine if robots could learn from watching demonstrations: you could show a domestic robot how to do routine chores or set a dinner table. In the workplace, you could train robots like new employees, showing them how to perform many duties. On the road, your self-driving car could learn how to drive safely by watching you drive around your neighborhood.

Making progress on that vision, USC researchers have designed a system that lets robots autonomously learn complicated tasks from a very small number of demonstrations—even imperfect ones. The paper, titled Learning from Demonstrations Using Signal Temporal Logic, was presented at the Conference on Robot Learning (CoRL), Nov. 18.

The researchers’ system works by evaluating the quality of each demonstration, so it learns from the mistakes it sees, as well as the successes. While current state-of-art methods need at least 100 demonstrations to nail a specific task, this new method allows robots to learn from only a handful of demonstrations. It also allows robots to learn more intuitively, the way humans learn from each other — you watch someone execute a task, even imperfectly, then try yourself. It doesn’t have to be a “perfect” demonstration for humans to glean knowledge from watching each other.

“Many machine learning and reinforcement learning systems require large amounts of data data and hundreds of demonstrations—you need a human to demonstrate over and over again, which is not feasible,” said lead author Aniruddh Puranic, a Ph.D. student in computer science at the USC Viterbi School of Engineering.

“Also, most people don’t have programming knowledge to explicitly state what the robot needs to do, and a human cannot possibly demonstrate everything that a robot needs to know. What if the robot encounters something it hasn’t seen before? This is a key challenge.”

Learning from demonstrations

Learning from demonstrations is becoming increasingly popular in obtaining effective robot control policies — which control the robot’s movements — for complex tasks. But it is susceptible to imperfections in demonstrations and also raises safety concerns as robots may learn unsafe or undesirable actions.

Also, not all demonstrations are equal: some demonstrations are a better indicator of desired behavior than others and the quality of the demonstrations often depends on the expertise of the user providing the demonstrations.

To address these issues, the researchers integrated “signal temporal logic” or STL to evaluate the quality of demonstrations and automatically rank them to create inherent rewards.

In other words, even if some parts of the demonstrations do not make any sense based on the logic requirements, using this method, the robot can still learn from the imperfect parts. In a way, the system is coming to its own conclusion about the accuracy or success of a demonstration.

“Let’s say robots learn from different types of demonstrations — it could be a hands-on demonstration, videos, or simulations — if I do something that is very unsafe, standard approaches will do one of two things: either, they will completely disregard it, or even worse, the robot will learn the wrong thing,” said co-author Stefanos Nikolaidis, a USC Viterbi assistant professor of computer science.

“In contrast, in a very intelligent way, this work uses some common sense reasoning in the form of logic to understand which parts of the demonstration are good and which parts are not. In essence, this is exactly what also humans do.”

Take, for example, a driving demonstration where someone skips a stop sign. This would be ranked lower by the system than a demonstration of a good driver. But, if during this demonstration, the driver does something intelligent — for instance, applies their brakes to avoid a crash — the robot will still learn from this smart action.
Adapting to human preferences

Signal temporal logic is an expressive mathematical symbolic language that enables robotic reasoning about current and future outcomes. While previous research in this area has used “linear temporal logic”, STL is preferable in this case, said Jyo Deshmukh, a former Toyota engineer and USC Viterbi assistant professor of computer science .

“When we go into the world of cyber physical systems, like robots and self-driving cars, where time is crucial, linear temporal logic becomes a bit cumbersome, because it reasons about sequences of true/false values for variables, while STL allows reasoning about physical signals.”

Puranic, who is advised by Deshmukh, came up with the idea after taking a hands-on robotics class with Nikolaidis, who has been working on developing robots to learn from YouTube videos. The trio decided to test it out. All three said they were surprised by the extent of the system’s success and the professors both credit Puranic for his hard work.

“Compared to a state-of-the-art algorithm, being used extensively in many robotics applications, you see an order of magnitude difference in how many demonstrations are required,” said Nikolaidis.

The system was tested using a Minecraft-style game simulator, but the researchers said the system could also learn from driving simulators and eventually even videos. Next, the researchers hope to try it out on real robots. They said this approach is well suited for applications where maps are known beforehand but there are dynamic obstacles in the map: robots in household environments, warehouses or even space exploration rovers.

“If we want robots to be good teammates and help people, first they need to learn and adapt to human preference very efficiently,” said Nikolaidis. “Our method provides that.”

“I’m excited to integrate this approach into robotic systems to help them efficiently learn from demonstrations, but also effectively help human teammates in a collaborative task.”


 


Contacts and sources: 
Amy Blumenthal
University of Southern California
 




Frequent, Rapid Testing Could Turn National COVID-19 Tide Within Weeks



Testing half the population weekly with inexpensive, rapid-turnaround COVID-19 tests would drive the virus toward elimination within weeks-- even if those tests are significantly less sensitive than gold-standard clinical tests, according to a new study published today by University of Colorado Boulder and Harvard University researchers.

Such a strategy could lead to "personalized stay-at-home orders" without shutting down restaurants, bars, retail stores and schools, the authors said.

A researcher holds up a rapid RT-Lamp test in a lab at the BioFrontiers Institute.


Credit: CU Boulder

"Our big picture finding is that, when it comes to public health, it's better to have a less sensitive test with results today than a more sensitive one with results tomorrow," said lead author Daniel Larremore, an assistant professor of computer science at CU Boulder. "Rather than telling everyone to stay home so you can be sure that one person who is sick doesn't spread it, we could give only the contagious people stay-at-home orders so everyone else can go about their lives."

For the study, published in the journal Science Advances, Larremore teamed up with collaborators at CU's BioFrontiers Institute and the Harvard T.H. Chan School of Public Health to explore whether test sensitivity, frequency, or turnaround time is most important to curb the spread of COVID-19.

The researchers scoured available literature on how viral load climbs and falls inside the body during infection, when people tend to experience symptoms, and when they become contagious.

They then used mathematical modeling to forecast the impact of screening with different kinds of tests on three hypothetical scenarios: in 10,000 individuals; in a university-type setting of 20,000 people; and in a city of 8.4 million.

When it came to curbing spread, they found that frequency and turnaround time are much more important than test sensitivity.

For instance, in one scenario in a large city, widespread twice-weekly testing with a rapid but less sensitive test reduced the degree of infectiousness, or R0 ("R naught"), of the virus by 80%. But twice-weekly testing with a more sensitive PCR (polymerase chain reaction) test, which takes up to 48 hours to return results, reduced infectiousness by only 58%. When the amount of testing was the same, the rapid test always reduced infectiousness better than the slower, more sensitive PCR test.

That's because about two-thirds of infected people have no symptoms and as they await their results, they continue to spread the virus.

"This paper is one of the first to show we should worry less about test sensitivity and, when it comes to public health, prioritize frequency and turnaround," said senior co-author Roy Parker, director of the BioFrontiers Institute and a Howard Hughes Medical Institute investigator.

The study also demonstrates the power of frequent testing in shortening the pandemic and saving lives.

In one scenario, in which 4% of individuals in a city were already infected, rapid testing three out of four people every three days reduced the number ultimately infected by 88% and was "sufficient to drive the epidemic toward extinction within six weeks."

The study comes as companies and academic research centers are developing low-cost, rapid turnaround tests that could be deployed in large public settings or commercialized for do-it-yourself use.

Sensitivity levels vary widely. Antigen tests require a relatively high viral load - about 1,000 times as much virus compared to the PCR test -- to detect an infection. Another test, known as RT-lamp (reverse transcription loop-mediated isothermal amplification), can detect the virus at around 100 times as much virus compared to the PCR. The benchmark PCR test requires as little as 5,000 to 10,000 viral RNA copies per milliliter of sample, meaning it can catch the virus very early or very late.

In the past, federal regulators and the public have been reluctant to embrace rapid tests out of concern that they may miss cases early in infection. But, in reality, an infected person can go from 5,000 particles to 1 million viral RNA copies in 18 to 24 hours, said Parker.

"There is a very short window, early in infection, in which the PCR will detect the virus but something like an antigen or LAMP test won't," Parker said.

And during that time, the person often isn't contagious, he said.

"These rapid tests are contagiousness tests," said senior co-author Dr. Michael Mina, an assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health. "They are extremely effective in detecting COVID-19 when people are contagious."

They are also affordable, he added. The rapid tests can cost as little as $1 each and return results in 15 minutes. Some PCR tests can take several days.

Mina envisions a day when the government sends simple, cheap DIY tests to every home. Even if half of Americans tested themselves weekly and self-isolated if positive, the result would be profound, he said.

"Within a few weeks we could see this outbreak going from huge numbers of cases to very manageable levels," Mina said.

Rapid testing could also be the key to breathing life back into former super spreader threats like football stadiums, concert venues and airports, with patrons testing themselves on the way in and still wearing masks as a precautionary measure, Larremore said.

"Less than .1% of the current cost of this virus would enable frequent testing for the whole of the U.S. population for a year," said Mina, referencing a recent Harvard economic analysis.

The authors say they are heartened to see that several countries have already begun testing all of their citizens, and hopeful that the new U.S. administration has named rapid testing as a priority.

"It's time to shift the mentality around testing from thinking of a COVID test as something you get when you think you are sick to thinking of it as a vital tool to break transmission chains and keep the economy open," Larremore said.



 

Contacts and sources:
Lisa Marshall
University of Colorado Boulder 
  





Study: TB Vaccine Linked to Lower Risk of Contracting COVID-19

A tuberculosis vaccine may offer protection from the virus that causes COVID-19 (coronavirus), according to a new Cedars-Sinai study. 


Photo by Getty.

A widely used tuberculosis vaccine is associated with reduced likelihood of contracting COVID-19 (coronavirus), according to a new study by Cedars-Sinai. The findings raise the possibility that a vaccine already approved by the U.S. Food and Drug Administration may help prevent coronavirus infections or reduce severity of the disease.

The vaccine, known as Bacillus Calmette-Guérin (BCG), was developed between1908 and 1921 and is administered to more than 100 million children around the world every year. In the U.S., it is FDA-approved as a drug to treat bladder cancer and as a vaccine for people at high risk of contracting TB. The BCG vaccine is currently being tested in multiple clinical trials worldwide for effectiveness against COVID-19.

In the new study, published online Nov. 19 in The Journal of Clinical Investigation, investigators tested the blood of more than 6,000 healthcare workers in the Cedars-Sinai Health System for evidence of antibodies to SARS-CoV-2, the virus that causes COVID-19, and also asked them about their medical and vaccination histories.

They found that workers who had received BCG vaccinations in the past-nearly 30% of those studied-were significantly less likely to test positive for SARS-CoV-2 antibodies in their blood or to report having had infections with coronavirus or coronavirus-associated symptoms over the prior six months than those who had not received BCG. These effects were not related to whether workers had received meningococcal, pneumococcal or influenza vaccinations.

The reasons for the lower SARS-CoV-2 antibody levels in the BCG group were not clear, according to Moshe Arditi, MD, director of the Pediatric and Infectious Diseases and Immunology Division at Cedars-Sinai and co-senior author of the study.

"It appears that BCG-vaccinated individuals either may have been less sick and therefore produced fewer anti-SARS-CoV-2 antibodies, or they may have mounted a more efficient cellular immune response against the virus," said Arditi, professor of Pediatrics and Biomedical Sciences. "We were interested in studying the BCG vaccine because it has long been known to have a general protective effect against a range of bacterial and viral diseases other than TB, including neonatal sepsis and respiratory infections."

In the new study, the lower antibody levels in the BCG group persisted despite the fact that these individuals had higher frequencies of hypertension, diabetes, cardiovascular diseases and COPD, which are known risk factors for being more susceptible to SARS-CoV-2 and developing the more severe forms of COVID-19 illness.

While noting that no one believes BCG will be more effective than a specific vaccine for COVID-19, Arditi explained that it could be more quickly approved and made available, given that it has a strong safety profile demonstrated by many years of use. "It is a potentially important bridge that could offer some benefit until we have the most effective and safe COVID19 vaccines made widely available," he said.

"Given our findings, we believe that large, randomized clinical trials are urgently needed to confirm whether BCG vaccination can induce a protective effect against SARS-CoV2 infection," said Susan Cheng, MD, MPH, MMSc, associate professor of Cardiology and director of Public Health Research at the Smidt Heart Institute at Cedars-Sinai. She was the other co-senior author of the study. The first author was Magali Noval Rivas, PhD, assistant professor of Pediatrics at Cedars-Sinai.

In fact, a number of randomized clinical trials have been launched to study the potential protective effects of BCG vaccination against COVID-19. Along with Texas A&M University, Baylor College of Medicine, and the University of Texas MD Anderson Cancer Center, Cedars Sinai is a site for the U.S. arm of this ongoing trial, which is recruiting hundreds of healthcare workers. Arditi serves as the principal investigator of this clinical trial at Cedars-Sinai.

"It would it be wonderful if one of the oldest vaccines that we have could help defeat the world's newest pandemic," Arditi said.

Research reported in this publication was supported by Cedars Sinai, the National Cancer Institute of the National Institutes of Health under award number U54 CA26059 and the Erika J. Glazer Family Foundation.

Read more in Discoveries magazine: On the Front Lines of COVID-19




Contacts and sources: 
Jane Engle
Cedars-Sinai.Medical Center



 



Neural Network Deceived by Visual Illusions Like Humans

Do neural networks dream visual illusions?

This is the question studied by researchers at the Department of Information and Communication Technologies, led by Marcelo Bertalmío together with Jesús Malo, a researcher at the University of Valencia.

In all three cases the Sagrada Familia has the same color, but is seen differently by the colors that surround it. This is a visual illusion.


Credit: UPF


Aconvolutional neural network is a type of artificial neural network in which the neurons are organized into receptive fields in a very similar way to neurons in the visual cortex of a biological brain. Today, convolutional neural networks (CNNs) are found in a variety of autonomous systems (for example, face detection and recognition, autonomous vehicles, etc.). This type of network is highly effective in many artificial vision tasks, such as in image segmentation and classification, along with many other applications.

Convolution networks were born inspired by the behavior of the human visual system, in particular in its basic structure formed by the concatenation of modules composed of a linear operation followed by a nonlinear operation. A study published in the advanced online edition of the journal Vision Research studies the phenomenon of visual illusions in convolution networks compared to their effect on human vision. A work by Alexander Gómez Vila , Adrian Martín , Javier Vázquez-Corral , Marcelo Bertalmío , members of the Department of Information and Communication Technologies ( DTIC ) and carried out with the participation of the researcherJesús Malo from the University of Valencia..

"Because of this connection of CNNs with our visual system, in this paper we wanted to see if convolutional networks suffer from similar problems to our visual system. Hence, we focused on visual illusions. Visual illusions are images that our brain perceives differently from how they actually are", explains Gómez Vila, first author of the study.

In their study, the authors trained CNNs for simple tasks also performed by human vision, such as denoising and deblurring. What they observed is that these CNNs trained under these experimental conditions are also "deceived" by brightness and colour visual illusions in the same way that visual illusions deceive humans.

Furthermore, as Gómez Villa explains, "for our work we also analyse when such illusions cause responses in the network that are not as physically expected, but neither do they match with human perception", that is to say, cases in which CNNs obtain a different optical illusion than the illusion that humans would perceive.

The results of this study are consistent with the long-standing hypothesis that considers low-level visual illusions as a by-product of the optimization to natural environments (that a human sees in their everyday). Meanwhile, these results highlight the limitations and differences between the human visual system and CNNs artificial neural networks.


Contacts and sources:
Núria Perez
Universitat Pompeu Fabra (UPF) - Barcelona


Publication: "Color illusions also deceive CNNs for low-level vision tasks: Analysis and Implications", Alexander Gómez Vila, Adrian Martín, Javier Vázquez-Corral, Marcelo Bertalmío, Jesús Malo (2020), September, Vision Research , advanced online edition. https://doi.org/10.1016/j.visres.2020.07.010





Thursday, November 19, 2020

Starved, Stuffed and Squandered: New Study Reveals Consequences of Decades of Global Nutrition Transition


Just a handful of rice and beans – a part of our world is starved. Hawaiian Pizza and ice-cream – another part of our world is stuffed, throwing away food every day. This gap is likely to worsen, while food waste will increase and pressure on the environment will go up, a new study shows. Researchers from the Potsdam Institute for Climate Impact Research (PIK) assessed the consequences if the current nutrition transition, from scarce starch-based diets towards processed foods and animal products, continues – the calculations combine, for the first time, estimates for under- and overweight, food composition and waste. Their findings provide a startling look ahead: By 2050, more than 4 billion people could be overweight, 1.5 billion of them obese, while 500 million people continue to be underweight.

Food futures: Hawaiian Pizza with a small salad and a banana.
 Copyrights: CC BY-NC-ND. Photography / Artwork by Jan von Holleben © 2019


“If the observed nutrition transition continues, we will not achieve the United Nations goal of eradicating hunger worldwide," explains Benjamin Bodirsky from PIK, lead author of the study just published in Scientific Reports. “At the same time, our future will be characterized by overweight and obesity of mind-blowing magnitude.” By 2050, 45 percent of the world's population could be overweight and 16 percent obese - compared to about 29 and 9 percent in 2010. This development is due to the insufficient global distribution of food as well as to the shift from scarcely processed plant‐based diets towards unbalanced, affluent diets, where animal protein, sugar and fat displace whole grains and pulses.

And that’s not all as Bodirsky underlines: "The increasing waste of food and the rising consumption of animal protein mean that the environmental impact of our agricultural system will spiral out of control. Whether greenhouse gases, nitrogen pollution or deforestation: we are pushing the limits of our planet - and exceed them."
Food systems as driver for greenhouse gas emissions

Crop and grazing land for food production cover about one third of the global land area; our food system is responsible for up to a third of global greenhouse gas emissions. The study projects that – if current trends continue – global food demand will increase by about 50% between 2010 and 2050, the demand for animal products like meat and milk will approximately double, a development that requires more and more land.

“Using the same area of land, we could produce much more plant-based food for humans than animal-based food,” explains co-author Alexander Popp, head of PIK’s Land Use Management Research Group. “To put it in a very simplistic way: If more people eat more meat, there’s less plant-based food for the others – plus we need more land for food production which can lead to forests being cut down. And greenhouse gas emissions rise as a consequence of keeping more animals.”

Global food demand: distribution and education are at the heart of the problem


The study provides a first-of-its kind, consistent long-term overview of a continued global nutrition transition from 1965 to 2100, using an open-source model that forecasts how much of food demand can be attributed to factors like population growth, ageing, increasing height, growing body mass index, declining physical activity and increasing food waste. Co-author Prajal Pradhan from PIK explains: “There is enough food in the world – the problem is that the poorest people on our planet have simply not the income to purchase it. And in rich countries, people don’t feel the economic and environmental consequences of wasting food.” But redistribution alone would not be sufficient, as actually both the poor and the rich eat poorly: There is a lack of knowledge about a healthy way of life and nutrition.
How to trigger an appetite for change?

“Unhealthy diets are the world’s largest health risks,” co-author Sabine Gabrysch, head of PIK´s Research Department on Climate Resilience explains. “While many countries in Asia and Africa currently still struggle with undernutrition and associated health problems, they are increasingly also faced with overweight, and as a consequence, with a rising burden of diabetes, cardiovascular disease and cancer,” she adds. The study could provide valuable orientation about the potential development pathway of different countries and regions. It could also support much-needed pro-active policies for a qualitative transition towards sustainable and healthy diets.

Sabine Gabrysch concludes: “We urgently need political measures to create an environment that promotes healthy eating habits. This could include binding regulations that limit the marketing of unhealthy snacks and promote sustainable and healthy meals in schools, hospitals and canteens. A stronger focus on nutrition education is also key, from early education in kindergarten to counseling by medical doctors and nurses. What we eat is of vital importance – both for our own health and that of our planet.”

Unbalanced diets: The shift from scarcity to overconsumption. The map colors show the prevalence of underweight and obesity in the population. For the 16 most populous countries, symbols indicate further details on body weight and height, dietary composition and food waste.
Credit: Potsdam Institute for Climate Impact Research (PIK)



Contacts and sources: 
Potsdam Institute for Climate Impact Research (PIK)


Publication: