Saturday, April 11, 2020

The science of how diet can change the way sugar tastes

by University of Sydney

The food animals eat can change how they perceive future food. This response uses the same machinery that the brain uses to learn, new research has found.

Researchers at the University of Sydney have discovered the basic science of how sweet taste perception is fine-tuned in response to different diets. While it has long been known that food can taste different based on previous experience, until now we didn't know the molecular pathways that controlled this effect.

Professor Greg Neely at the Charles Perkins Centre and School of Life and Environmental Sciences with Professor Qiaoping Wang (formerly at the Charles Perkins Centre and now based at Sun Yat-Sen University, China) used fruit flies to study sweet taste. They learned that taste is highly subjective based on previous experience.

Professor Neely said they learned four important things:

The food animals eat can change how they perceive future food.
This response uses the same machinery that the brain uses to learn.
Pathways that can extend lifespan were also involved in enhancing taste perception, and diets in fruit flies that promote long life were also found to enhance taste perception.
Lifespan, learning and sensory perception are linked in ways we are just starting to understand.

Fruit fly 'tongue'

"We found that the fruit fly 'tongue' – taste sensors on its proboscis and front feet—can learn things using the same molecular pathways that the fly brain uses to learn things," Professor Neely said. "Central to this is the neurotransmitter dopamine."

"It turns out these are also the same chemical pathways that humans use to learn and remember all sorts of things," Professor Neely said. "This really highlights how learning is a whole-body phenomenon; and was a complete surprise to us."

Professor Wang, who led the study, said: "We were surprised to find that a protein-restricted diet that makes an animal live much longer also turns up the intensity of sucrose perception for that animal, and that is dependent on the same learning and longevity pathways.

"The response was also really specific. For example, when we fed flies food that had no sweetness, the animals' sweet taste perception was enhanced, but only for glucose, not for fructose. We have no idea why they specifically focus just on one kind of sugar when they perceive them both as sweet."

"We also found that eating high amounts of sugar suppressed sweet taste perception, making sugar seem less sweet," Professor Neely said. "This finding, which occurs through a different mechanism, matched nicely with recent results from our colleague Monica Dus at the University of Michigan, who is the world expert in this area."

Taste study

The researchers found if they changed the diet of the fruit fly (increasing sugar, removing taste of sugar, increasing protein, changing sugar for complex carbohydrate), this drastically altered how well the fruit fly could taste subsequent sugar after a few days.

"We found that when flies ate unsweetened food, this made sugary food taste much more intense," Professor Wang said.

"Then we looked at all the proteins that changed in the fruit fly 'tongue' in response to diet, and we investigated what was happening," Professor Neely said.

They found the sensation of taste is controlled by dopamine (the "reward" neuromodulator). The researchers then mapped the pathway and found the same pathways that are well established as controlling learning and memory or promoting long life also enhance taste sensation.

"While this work was conducted in fruit flies, the molecules involved are conserved through to humans. We know humans also experience changes in taste perception in response to diet, so it's possible the whole process is conserved; we will have to see," Professor Wang said.

The research published in Cell reports, is a follow up study to Professor's Neely's work testing the effects of artificial sweeteners. That research found artificial sweeteners activate a neuronal starvation pathway, and end up promoting increased food intake, especially when combined with a low-carb diet.

"Our first studies were focused on how different food additives impact the brain, and from this we found taste changed in response to diet, so here we followed up that observation and describe how that works," Professor Neely said. "Turns out the fly 'tongue' itself is remembering what has come before, which is kind of neat."

Fat fruit flies: High-sugar diet deadens sweet tooth; promotes overeating, obesity in flies

More information: Qiao-Ping Wang et al. PGC1α Controls Sucrose Taste Sensitization in Drosophila, Cell Reports (2020). DOI: 10.1016/j.celrep.2020.03.044

Journal information: Cell Reports

Video games improve the visual attention of expert players

by Frontiers

Action real-time strategy video games such as World of Warcraft, Age of Empires, and Total War are played by millions. These games, which can be won through strategic planning, selective attention, sensorimotor skills, and teamwork place considerable demands on the brain.

Research has shown that experience of playing games can improve cognitive development such as greater sensitivity to contrasts, better eye-to-hand coordination, and superior memory. But the long-term effects of gaming on a key cognitive function called temporal visual selective attention—the capacity to distinguish between important and irrelevant information within a rapid stream of visual stimuli—has never been studied.

Here, researchers show for the first time that expert players of real-time strategy games have faster information processing, allocate more cognitive power to individual visual stimuli, and allocate limited cognitive resources between successive stimuli more effectively through time. These findings in Frontiers in Human Neuroscience suggest that playing such games can cause long-term changes in the brain and lead to an improvement in temporal visual selective attention.

"Our aim was to evaluate the long-term effect of experience with action real-time strategy games on temporal visual selective attention," says author Dr. Diankun Gong, Associate Professor in the Ministry of Education Key Laboratory for Neuroinformation at the University of Electronic Science and Technology of China.

"In particular, we wanted to reveal the time course of cognitive processes during the attentional blink task, a typical task used by neuroscientists to study visual selective attention."

Attentional blink is the tendency of focused observers to "blink"—that is, to fail to properly register—a visual stimulus if it appears so quickly after a previous stimulus that cognitive processing of the first hasn't finished. In a typical blink task, human subjects are shown a stream of digits and letters in quick succession (with 100 ms intervals) and asked to press a button each time they see one of two target letters (for example D and M).

People often "blink" a second target if it appears within 200-500 ms of the first, and electroencephalograms (EEGs) suggest that this is due to competition for cognitive resources between the first stimulus—with the need to encode it in working and episodic memory, and to select the appropriate response—versus the second. In other words, people often fail to register M because brain resources are temporarily used up by the ongoing need to process any D shown more than 200 ms and less than 500 ms earlier.

To study the effect of gaming on temporal visual selective attention, Gong and colleagues selected 38 volunteers, health young male students from the University of Electronic Science and Technology. Half of the volunteers were expert players of the typical action real-time strategy game League of Legend, where teammates work together to destroy the towers of an opposing team. They had played the game for at least two years and were masters, based on their ranking among the top 7% of players. The others were beginners, with less than six months experience of the same game, and ranked among the bottom 30-45%. All volunteers were seated in front of a screen and tested in a blink task, with 480 trials over a period of approximately 2 h. The greater a volunteer's tendency to "blink" targets, the less frequently he would press the correct button when one of the two targets appeared on the screen, and the worse he did overall in the task.

The volunteers also wore EEG electrodes on the parietal (i.e. sides and top) region of their scalp, allowing the researchers to measure and localize the brain's activity throughout the experiment. These electrodes recorded Event-Related Potentials (ERPs), tiny electric potentials (from -6 to 10 μV) that last from 0 to 800 ms after each non-blinked stimulus, and which represent the neural processes for registering and consolidating its memory. The researchers focused on the so-called P3b phase of the ERP, a peak between 200 and 500 ms after the stimulus, because previous research has shown that its timing and amplitude accurately reflects performance in the blink task: the later P3b occurs and the less pronounced it is, the more likely it is that a stimulus will be "blinked".

"We found that expert League of Legend players outperformed beginners in the task. The experts were less prone to the blink effect, detecting targets more accurately and faster, and as shown by their stronger P3b, gave more attentional cognitive resources to each target," says coauthor Dr. Weiyi Ma, Assistant Professor in Human Development and Family Sciences at the University of Arkansas, USA.

"Our results suggest that long-term experience of action real-time strategy games leads to improvements in temporal visual selective attention: the expert gamers had become more effective in distributing limited cognitive resources between successive visual targets," says author Dr. Tiejun Liu. "We conclude that such games can be a powerful tool for cognitive training."

One hour of video gaming can increase the brain's ability to focus

More information: Xianyang Gan et al, Action Real-Time Strategy Gaming Experience Related to Increased Attentional Resources: An Attentional Blink Study, Frontiers in Human Neuroscience (2020). DOI: 10.3389/fnhum.2020.00101

Journal information: Frontiers in Human Neuroscience

Provided by Frontiers

Study: Money can't buy love – or friendship

by Bert Gambini, University at Buffalo

Credit: CC0 Public Domain

While researchers have suggested that individuals who base their self-worth on their financial success often feel lonely in everyday life, a newly published study by the University at Buffalo and Harvard Business School has taken initial steps to better understand why this link exists.

"When people base their self-worth on financial success, they experience feelings of pressure and a lack of autonomy, which are associated with negative social outcomes," says Lora Park, an associate professor of psychology at UB and one of the paper's co-authors.

"Feeling that pressure to achieve financial goals means we're putting ourselves to work at the cost of spending time with loved ones, and it's that lack of time spent with people close to us that's associated with feeling lonely and disconnected," says Deborah Ward, a UB graduate student and adjunct faculty member at the UB's psychology department who led the research on a team that also included Ashley Whillans, an assistant professor at Harvard Business School, Kristin Naragon-Gainey, at the University of Western Australia, and Han Young Jung, a former UB graduate student.

The findings, published in the journal Personality and Social Psychology Bulletin, emphasize the role of social networks and personal relationships in maintaining good mental health and why people should preserve those connections, even in the face of obstacles or pursuing challenging goals.

"Depression and anxiety are tied to isolation, and we're certainly seeing this now with the difficulties we have connecting with friends during the COVID-19 pandemic," says Ward. "These social connections are important. We need them as humans in order to feel secure, to feel mentally healthy and happy. But much of what's required to achieve success in the financial domain comes at the expense of spending time with family and friends."

Ward says it's not financial success that's problematic or the desire for money that's leading to these associations.

At the center of this research is a concept psychologists identify as Financial Contingency of Self-Worth. When people's self-worth is contingent on money, they view their financial success as being tied to the core of who they are as a person. The degree to which they succeed financially relates to how they feel about themselves—feeling good when they think they're doing well financially, but feeling worthless if they're feeling financially insecure.

The research involved more than 2,500 participants over five different studies that looked for relationships between financial contingency of self-worth and key variables, such as time spent with others, loneliness and social disconnection. This included a daily diary study that followed participants over a two-week period to assess how they were feeling over an extended time about the importance of money and time spent engaged in various social activities.

"We saw consistent associations between valuing money in terms of who you are and experiencing negative social outcomes in previous work, so this led us to ask the question of why these associations are present," says Ward. "We see these findings as further evidence that people who base their self-worth on money are likely to feel pressured to achieve financial success, which is tied to the quality of their relationships with others."

Ward says the current study represents the beginning of efforts to uncover the processes at work with Financial Contingency of Self-Worth.

"I hope this is part of what becomes a longer line of research looking at the mechanisms between valuing money and social-related variables," says Ward. "We don't have the final answer, but there is a lot of evidence that pressures are largely playing a role."

Explore further

Staking self-worth on the pursuit of money has negative psychological consequences
More information: Deborah E. Ward et al, Can't Buy Me Love (or Friendship): Social Consequences of Financially Contingent Self-Worth, Personality and Social Psychology Bulletin (2020). DOI: 10.1177/0146167220910872

Journal information: Personality and Social Psychology Bulletin

Provided by University at Buffalo

Analysis: Household cleaning products effective against coronavirus

by Dr Lena Ciric, The Conversation

COVID-19 has only been around for a few months, so at this point scientists don't know that much about it. But more is being learned every day. We now know, for example, it can live on surfaces for up to nine days and survives in the air for a few hours. We also now know that the virus particles are shed through saliva and fluids coughed up from the lungs. And that the virus can also be shed from our faeces.

It's easy for an infected person to spread the virus particles through coughing, touching other people or leaving the virus on surfaces. Undoubtedly, hand-washing after being in public spaces is key to reduce the spread of COVID-19. But what should we be doing in our homes to eliminate it?

Two recent studies have investigated how long coronaviruses survive on different surfaces. The research looked at a number of different viruses including SARS-CoV-2—the coronavirus that has caused COVID-19. And it found that the survival times varied according to the type of surface.

The virus survived for longest on stainless steel and plastic—for up to nine days. The shortest survival times of one day was for paper and cardboard.

The amount of virus particles during this time does reduce, but it's worrying that the particles can last for days rather than hours or minutes on a surface. So, how good are the cleaning products already in your cupboards at killing SARS-CoV-2? There is some good news in the list below.

Soap and water

Soap and water are your first line of defence to remove the virus from surfaces. Soap interferes with the fats in the virus shell and lift the virus from surfaces and this is then rinsed off by water. Of course, you also need to wash your hands when you come in from the shops and wash your food as normal.

Bleach

The active ingredient in bleach—sodium hypochlorite—is very effective at killing the virus. Make sure you leave the bleach to work for 10-15 minutes then give the surface a wipe with a clean cloth. The bleach works by destroying the protein and what's known as the ribonucleic acid (RNA) of the virus—this is the substance that gives the blueprint for making more virus particles when you become infected. Be sure to use the bleach as directed on the bottle.

Surgical spirit

Surgical spirit is mostly made up of the alcohol ethanol. Ethanol has been shown to kill coronaviruses in as little as 30 seconds. Like bleach, the alcohol destroys the protein and RNA that the virus is made up of. Moisten a cloth with some neat surgical spirit and rub it over a surface. This will evaporate and you will not need to wipe it off.

Surface wipes

The active ingredient in surface wipes in an antiseptic –- usually benzalkonium chloride. AKA QUATS The wipes work by physically removing germs through the pressure you apply when you use them, and the germs then attach to the wipe.

They also leave a layer of the antiseptic on the surface that works to kill germs. The antiseptic works well on bacteria as well as on coronaviruses that infect mice and dogs—but it seems to make no difference to the spread of human coronavirus. Antiseptics work by disrupting the fats in pathogen cells, but SARS-CoV-2 does not contain many fats. So far, there is no evidence that antiseptics can kill human coronaviruses.

Hand sanitisers

A word of warning though about hand sanitisers. The main ingredient in hand sanitisers that will kill SARS-CoV-2 is ethanol, the alcohol in surgical spirit. But its concentration in the sanitiser is very important –- it has to be over 70 % or it will not kill the virus effectively.

One thing you can also do is make sure you air out the spaces you are spending time in regularly. An infected person will produce thousands of tiny droplets which contain the virus every time they cough. SARS-CoV-2 can survive in the air for up to three hours. So by opening the window, you can remove and disperse the droplets and reduce the amount of virus in the air—which will reduce the risk of infection for others.

We are living in uncertain times but it's reassuring to know that we have some weapons we can use to fight COVID-19 in our homes. The bottom line: keep washing your hands, use 70% hand sanitiser, dust off the bleach and open a window to let in the spring air.

Review examines how building design can influence disease transmission

by Andy Fell, UC Davis

Credit: CC0 Public Domain

Social distancing has Americans mostly out of the places they usually gather and in their homes as we try to reduce the spread of COVID-19. But some buildings, such as hospitals and grocery stores, have to remain open, and at some point, most of us will go back to the office or workplace. What is the role of building design in disease transmission, and can we change how we design the built environment to make it healthier?

Those questions are addressed in a review just published in the journal mSystems by David Coil, project scientist, and Professor Jonathan Eisen at the UC Davis Genome Center and School of Medicine; and colleagues at the Biology and the Built Environment Center, University of Oregon.

Among the simplest suggestions for healthier buildings: opening windows to improve air circulation and opening blinds to admit natural daylight.

While more research needs to be done on the effect of sunlight on SARS-CoV-2 indoors, "Daylight exists as a free, widely available resource to building occupants with little downside to its use and many documented positive human health benefits," the authors write.

We spend almost all of our daily lives inside human-built environments whether homes, vehicles or workplaces. Built environments provide lots of opportunities for people to come into contact with viruses and bacteria—through air flow, from surfaces and also from the way buildings make us interact with each other.

So far, the only documented route of transmission of SARS-CoV-2 is directly from person to person. But viruses also settle on surfaces, which can become heavily contaminated quite quickly. How long SARS-CoV-2 survives on surfaces is still up for debate. Estimates range from a couple of hours to a few days, depending on the material and conditions. Regularly cleaning surfaces and thorough handwashing are important.

Air flow and humidity

Viral particles are too small to be blocked by HEPA and MERV air filters, but ventilation strategies can still play a role in reducing disease transmission, the authors write. Increasing the amount of air flowing in from outside and the rate of air exchange can dilute virus particles indoors. This can include "perimeter ventilation"—opening a window, when outdoor temperatures allow it. However, high air flow could also stir up settled particles and put them back in the air—and it also uses more energy.

Virus particles like drier air, so maintaining a high relative humidity can help. Virus-bearing droplets get bigger in humid air, meaning they settle out more quickly and don't travel as far. Humidity also seems to interfere with the lipid envelope around viruses such as SARS-CoV-2. Too much humidity, however, can promote mold growth.
Modern buildings are generally designed to promote social mixing—from open plan living areas in homes to open offices where many workers share space. By promoting interaction and chance encounters, these layouts are thought to generate more creativity and teamwork. At the same time, they are probably also really great for spreading viruses around.

It may not be practical in the short term to make big changes in office layout. But understanding how layout and the ways people use shared spaces affect disease transmission could help in developing effective social distancing measures and making decisions about when people can go back to work.

Explore further

Hopes for pandemic respite this spring may depend upon what happens indoors
More information: Leslie Dietz et al, 2019 Novel Coronavirus (COVID-19) Pandemic: Built Environment Considerations To Reduce Transmission, mSystems (2020). DOI: 10.1128/mSystems.00245-20
Provided by UC Davis

Cats are far more susceptible to new coronavirus than dogs are, but people shouldn't be 'fearful' of their pets: study

by Mark Johnson, Milwaukee Journal Sentinel

If your cat is being socially distant these days, maybe he's just trying to protect both of you.

A Chinese study published Wednesday in the journal Science reported that tests of the new coronavirus on domesticated cats, dogs, pigs, chickens, ducks and ferrets found that both cats and ferrets are highly susceptible to the virus. Cats can become infected through airborne transmission. Dogs, however, have a very low susceptibility to the virus.

Susceptibility means that a virus is able to enter a cell.

Specialists in veterinary medicine stressed that the study included very small numbers of cats and dogs, which were injected with much higher levels of the new coronavirus than they would likely encounter in the natural world. They also said it is highly unlikely that a person would become infected from a pet.

"I don't think that for most people cat-to-human transmission is the most likely way that they would be infected, but I'd be very surprised if this was impossible," said David O'Connor, a professor of pathology and laboratory medicine at the University of Wisconsin-Madison.

"This is a human disease," said Jeanette O'Quin, an assistant professor in the Department of Veterinary Preventive Medicine at Ohio State University. "It's being transferred from person to person. That is our greatest risk."

Still, the new paper follows a scattering of reports of animals becoming infected with the new coronavirus. Less than a week ago the Bronx Zoo announced that a 4-year-old Malayan tiger, named Nadia, tested positive for COVID-19.

A separate Chinese study reported that after the outbreak began in Wuhan, 14% of cats in the area were found to have antibodies for the virus, O'Connor said.

In Hong Kong, a recent study examined 17 dogs and eight cats taken from households where a human had become sick with COVID-19 or had come in close contact with a confirmed patient. In that group, two dogs tested positive, though one was deemed to be "a weak" positive. The cats were not positive at the most recent testing.

Jane Sykes, a professor of small animal medicine at the University of California, Davis School of Veterinary Medicine, cited a much larger report by a major veterinary laboratory, IDEXX, involving more than 4000 samples taken from dogs, cats and horses. None of the animals showed any evidence of the new coronavirus.

The samples were collected from animals in the U.S. and South Korea during a four-week period, starting on Feb. 14.

"There's a lot of stress in the world and the human-animal bond is so important," Sykes said. "We should be enjoying our pets, rather than being fearful of them."

Sykes and O'Quin both recommended steps people can take to reduce the small risk of the virus passing between people and their pets.

Sykes said that people who have COVID-19 should probably keep the pet in another part of the house and have another person in the household care for it. If there is no one else to care for the pet, the infected person should wear a mask when caring for the pet and wash their hands before and after feeding the animal. She also advised people not to allow a pet to lick them in the mouth.

Although the risk of the virus passing between pets and people "is really low, we should take precautions," O'Quin said.

If pet owners are quarantining themselves, they should also quarantine their cats inside.

"If you're not sick," O'Quin said, "you can interact with them pretty much the way you would always."

With Bronx Zoo tiger catching coronavirus, should pet owners be concerned about COVID-19? Health experts weigh in

More information: Jianzhong Shi et al. Susceptibility of ferrets, cats, dogs, and other domesticated animals to SARS–coronavirus 2, Science (2020). DOI: 10.1126/science.abb7015

Expert reactions to a study looking at susceptibility of pets to the COVID-19 virus (SARS-CoV-2): https://www.sciencemediacentre.org/expert-reaction-to-a-study-looking-at-susceptibility-of-pets-to-the-covid-19-virus-sars-cov-2/

Why Africa's coronavirus outbreak appears slower than anticipated

SHIT HOLE COUNTRIES DOING BETTER THAN TRUMP USA
Philippe ALFROY with AFP bureaus,AFP•April 11, 2020

Coronavirus has since spread to 52 African countries, but despite a steady rise in confirmed cases, the continent continues to lag behind the global curve for infections and deaths (AFP Photo/Yasuyoshi CHIBA)

Johannesburg (AFP) - When Africa's first case of coronavirus was detected in Egypt in February, the rest of the continent prepared for the brunt of a pandemic that has engulfed Europe and spread to the United States, infecting more than 1.6 million worldwide.

Health experts warned of the devastation the deadly virus could cause in Africa, where most hospitals are desperately short of equipment and trained staff.

Coronavirus has since spread to 52 African countries, but despite a steady rise in the number of confirmed cases, the continent continues to lag behind the global curve for infections and deaths.

Still, the World Health Organization last month warned Africa faced a dramatic evolution of the pandemic even as governments imposed restrictions to help curb the spread. The continent appears poorly equipt to manage a major health crisis and is struggling to test enough to monitor virus cases

Where does Africa stand?

To date the novel respiratory disease has infected more than 12,800 people on the continent and killed at least 692, according to a tally compiled by AFP.

Only the Comoros archipelago and the tiny kingdom of Lesotho have not yet detected any cases.

South Africa is the worst-affected country, with over 2,000 confirmed cases and 24 recorded deaths so far -- well behind the more than 871,000 cases and 71,000 deaths counted in Europe to date.

Experts, however, warn that the tide is rising.

"During the last four days we can see that the numbers have already doubled," said Michel Yao, the World Health Organization (WHO) Africa's emergency response programme manager.

"If the trend continues... some countries may face a huge peak very soon," Yao told AFP.

WHO Africa Director Matshidiso Moeti echoed the concern, adding that the spread of COVID-19 outside major cities opened "a new front in our fight against this virus".

Are numbers underestimated?

Possibly the greatest question mark in analyses of coronavirus in Africa, compounded by a global lack of testing capacity.

Despite a donation of more than one million coronavirus testing kits by Chinese billionaire Jack Ma, most African countries lack the equipment needed to detect the disease.

South Africa -- which has the most advanced healthcare system in sub-Saharan Africa -- has so far only managed to test around 73,000 of its 57 million inhabitants.

"This is way too low for the kind of challenges South Africa is facing," said the country's Health Minister Zweli Mkhize, who is aiming to scale up to 30,000 tests per day.

Nigeria, Africa's biggest economy, has only carried out 5,000 coronavirus tests to date for a country of 190 million people.

"The testing system is quite overloaded," admitted a doctor working at a private clinic in Lagos, who asked not to be identified.

"It takes time for... the results," he added. "And are they accurate? We don't know."

Inability to test for the virus has forced several countries to work with vague and sometimes misleading estimates.

Kenya, for instance, has predicted its number of coronavirus cases to reach 10,000 by the end of April.

Ten days into the month, the number of detected infections remained lower than 200.

Director General of Kenya's health ministry, Patrick Amoth earlier this week said that was because they had not done community-based testing.

Kenya has since received 7,000 testing kits and machines that can process up to 3,000 samples in two hours. The government aims to roll out mass testing within the next three weeks.

"We utilise these machines to reach a bigger population so that we can be able to tell... if we are winning the battle or if we need to change our strategy," Amoth said during a televised briefing on Saturday.

The head of the Africa Centres for Disease Control and Prevention, John Nkengasong, admitted that Africa's coronavirus statistics were far from "perfect".

"We just lack the means," he told AFP.

But Nkengasong dismissed claims that a high number of infections had slipped under the radar, pointing out that hospitals "would be flooded with people" if that was the case.

Have lockdowns, curfews worked?

The delayed spread of coronavirus gave African countries some leeway to roll out the same measures implemented in Europe to stem the disease.

Governments across the continent reacted ahead of time, closing borders and imposing lockdowns and curfews when just a handful of cases had been detected.

Those measures have been tricky to enforce in impoverished and densely populated neighbourhoods, where houses are overcrowded and most survive off informal work -- making it almost impossible to remain home.

The WHO's Moeti cautioned that it was "too early to say" whether anti-coronavirus measures were slowing the epidemic in Africa.

Meanwhile, South Africa's President Cyril Ramaphosa said earlier this week that there was "sufficient evidence" to show that a nation-wide lockdown was "working".

"In the two weeks before the lockdown, the average daily increase in new cases was around 42 percent. Since the start of the lockdown, the average daily increase has been around 4 percent," Ramaphosa said on Thursday, as he announced an extension of the 21-day shutdown.

Has Africa had enough time to prepare?

The time gained by African governments could be offset by a lack of means.

"There is a severe shortage of treatment facilities for critical cases of Covid-19," said a WHO statement.

There are barely five intensive care unit beds per one million people in Africa, compared to 4,000 in Europe, according to the organisation.

Public hospitals only have 2,000 medical ventilators between them to serve the whole continent.

Still no one dares make any predictions on the proportions the novel coronavirus could reach in Africa.

The WHO noted that 31 countries on the continent had less than 100 confirmed cases and believed "containment was possible".

Yet the threat remains.

"COVID-19 has the potential to cause thousands of deaths," said the WHO's Moeti. "To also unleash economic and social devastation."

burs-pa/bed/sch/pma

Protective gene in wild wheatgrass could stop fusarium head blight in wheat and barley

by Bob Yirka , Phys.org

A team of researchers from several institutions in China, one in the U.S. and one in Israel, has found a protective gene in wild wheatgrass that shows promise in stopping fusarium head blight in wheat and barley crops. In their paper published in the journal Science, the group describes how they found the gene and how well it has worked against fungal infections in test crops.

Fusarium head blight is a growing concern among wheat and barley growers around the world—also known as wheat scab, the fungus eats the grain in such plants, reducing yields. Worse, it leaves behind toxins in the uneaten grain, making it unsellable. Farmers have tried a wide variety of antifungal agents to rid their crops of the infections, but have not made much progress because the fungus attacks during the wet seasons—rain washes away the treatments. One approach that has seen some degree of success is genetically engineering certain wheat types to express a gene that has been found to confer some degree of resistance in a Chines heirloom—but it has thus far proven to provide only modest protection. In this new effort, the researchers have found a gene in a wild grass that is resistant to Fusarium graminearum—the fungus behind head blight—that appears to confer stronger resistance to infections.

The work involved a very long-term study of the wheatgrass Thinopyrum elongatum—early on, they discovered that it was resistant to F. graminearum. But it took nearly two decades to figure out which of its genes provided resistance—Fhb7. They found it coded for an enzyme called glutathione S-transferase, which works by degrading toxins in the fungus that lead to the blight seen in crops. The next step involved adding the gene to wheat plants at a test facility to find out if it had unwanted side-effects. Thus far, they have found that adding the gene to wheat plants makes them more resistant to F. graminearum—and it does not reduce crop yields. They note that more testing is required to determine how effective the gene is at helping the plants ward off infections, and also to find out what happens when it is used with the gene from the Chines heirlooms.

Cause of wheat resistance to scab discovered

More information: Hongwei Wang et al. Horizontal gene transfer of Fhb7 from fungus underlies Fusarium head blight resistance in wheat, Science (2020). DOI: 10.1126/science.aba5435

POSTMODERN ALCHEMY

First sighting of mysterious Majorana fermion on a common metal

by Jennifer Chu, Massachusetts Institute of Technology

Physicists at MIT and elsewhere have observed evidence of Majorana fermions—particles that are theorized to also be their own antiparticle—on the surface of a common metal: gold. This is the first sighting of Majorana fermions on a platform that can potentially be scaled up. The results, published in the Proceedings of the National Academy of Sciences, are a major step toward isolating the particles as stable, error-proof qubits for quantum computing.

In particle physics, fermions are a class of elementary particles that includes electrons, protons, neutrons, and quarks, all of which make up the building blocks of matter. For the most part, these particles are considered Dirac fermions, after the English physicist Paul Dirac, who first predicted that all fermionic fundamental particles should have a counterpart, somewhere in the universe, in the form of an antiparticle—essentially, an identical twin of opposite charge.

In 1937, the Italian theoretical physicist Ettore Majorana extended Dirac's theory, predicting that among fermions, there should be some particles, since named Majorana fermions, that are indistinguishable from their antiparticles. Mysteriously, the physicist disappeared during a ferry trip off the Italian coast just a year after making his prediction. Scientists have been looking for Majorana's enigmatic particle ever since. It has been suggested, but not proven, that the neutrino may be a Majorana particle. On the other hand, theorists have predicted that Majorana fermions may also exist in solids under special conditions.

Now the MIT-led team has observed evidence of Majorana fermions in a material system they designed and fabricated, which consists of nanowires of gold grown atop a superconducting material, vanadium, and dotted with small, ferromagnetic "islands" of europium sulfide. When the researchers scanned the surface near the islands, they saw signature signal spikes near zero energy on the very top surface of gold that, according to theory, should only be generated by pairs of Majorana fermions.

"Majorana ferminons are these exotic things, that have long been a dream to see, and we now see them in a very simple material—gold," says Jagadeesh Moodera, a senior research scientist in MIT's Department of Physics. "We've shown they are there, and stable, and easily scalable."

"The next push will be to take these objects and make them into qubits, which would be huge progress toward practical quantum computing," adds co-author Patrick Lee, the William and Emma Rogers Professor of Physics at MIT.

Lee and Moodera's coauthors include former MIT postdoc and first author Sujit Manna (currently on the faculty at the Indian Institute of Technology at Delhi), and former MIT postdoc Peng Wei of University of California at Riverside, along with Yingming Xie and Kam Tuen Law of the Hong Kong University of Science and Technology.

High risk

If they could be harnessed, Majorana fermions would be ideal as qubits, or individual computational units for quantum computers. The idea is that a qubit would be made of combinations of pairs of Majorana fermions, each of which would be separated from its partner. If noise errors affect one member of the pair, the other should remain unaffected, thereby preserving the integrity of the qubit and enabling it to correctly carry out a computation.

Scientists have looked for Majorana fermions in semiconductors, the materials used in conventional, transistor-based computing. In their experiments, researchers have combined semiconductors with superconductors—materials through which electrons can travel without resistance. This combination imparts superconductive properties to conventional semiconductors, which physicists believe should induce particles in the semiconductor to split , forming the pair of Majorana fermions.

"There are several material platforms where people believe they've seen Majorana particles," Lee says. "The evidence is stronger and stronger, but it's still not 100 percent proven."

What's more, the semiconductor-based setups to date have been difficult to scale up to produce the thousands or millions of qubits needed for a practical quantum computer, because they require growing very precise crystals of semiconducting material and it is very challenging to turn these into high-quality superconductors.

About a decade ago, Lee, working with his graduate student Andrew Potter, had an idea: Perhaps physicists might be able to observe Majorana fermions in metal, a material that readily becomes superconductive in proximity with a superconductor. Scientists routinely make metals, including gold, into superconductors. Lee's idea was to see if gold's surface state—its very top layer of atoms—could be made to be superconductive. If this could be achieved, then gold could serve as a clean, atomically precise system in which researchers could observe Majorana fermions.

Lee proposed, based on Moodera's prior work with ferromagnetic insulators, that if it were placed atop a superconductive surface state of gold, then researchers should have a good chance of clearly seeing signatures of Majorana fermions.

"When we first proposed this, I couldn't convince a lot of experimentalists to try it, because the technology was daunting," says Lee who eventually partnered with Moodera's experimental group to to secure crucial funding from the Templeton Foundation to realize the design. "Jagadeesh and Peng really had to reinvent the wheel. It was extremely courageous to jump into this, because it's really a high-risk, but we think a high-payoff, thing."

"Finding Majorana"

Over the last few years, the researchers have characterized gold's surface state and proved that it could work as a platform for observing Majorana fermions, after which the group began fabricating the setup that Lee envisioned years ago.

They first grew a sheet of superconducting vanadium, on top of which they overlaid nanowires of gold layer, measuring about 4 nanometers thick. They tested the conductivity of gold's very top layer, and found that it did, in fact, become superconductive in proximity with the vanadium. They then deposited over the gold nanowires "islands" of europium sulfide, a ferromagnetic material that is able to provide the needed internal magnetic fields to create the Majorana fermions.

The team then applied a tiny voltage and used scanning tunneling microscopy, a specialized technique that enabled the researchers to scan the energy spectrum around each island on gold's surface.

Moodera and his colleagues then looked for a very specific energy signature that only Majorana fermions should produce, if they exist. In any superconducting material, electrons travel through at certain energy ranges. There is however a desert, or "energy gap" where there should be no electrons. If there is a spike inside this gap, it is very likely a signature of Majorana fermions.

Looking through their data, the researchers observed spikes inside this energy gap on opposite ends of several islands along the the direction of the magnetic field, that were clear signatures of pairs of Majorana fermions.

"We only see this spike on opposite sides of the island, as theory predicted," Moodera says. "Anywhere else, you don't see it."

"In my talks, I like to say that we are finding Majorana, on an island in a sea of gold," Lee adds.

Moodera says the team's setup, requiring just three layers—gold sandwiched between a ferromagnet and a superconductor—is an "easily achievable, stable system" that should also be economically scalable compared to conventional, semiconductor-based approaches to generate qubits.

"Seeing a pair of Majorana fermions is an important step toward making a qubit," Wei says. "The next step is to make a qubit from these particles, and we now have some ideas for how to go about doing this."New material shows high potential for quantum computing

More information: Sujit Manna et al. Signature of a pair of Majorana zero modes in superconducting gold surface states, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.1919753117

Journal information: Proceedings of the National Academy of Sciences

New species discovered during exploration of abyssal deep sea canyons off Ningaloo

by Schmidt Ocean Institute

A rare deep-sea hydroid is discovered by Dr Nerida Wilson (Chief Scientist, Western Australian Museum) and her team. The animal was found at 2497 m in Cape Range Canyon using ROV SuBastian. Branchiocerianthus is a giant hydroid that consists of a single polyp on a long stem living on a sandy bottom. It is a close relative of corals, anemones and sea fans. It is the first time this amazing animal has been filmed and collected in Australian waters. Others have been found elsewhere in the world including Japan, Ireland and Norway. In the control room, everyone looks on in amazement. Credit: Schmidt Ocean Institute/ Alex Ingle

An estimated 150-foot siphonophore— seemingly the longest animal ever recorded was discovered during a month-long scientific expedition exploring the submarine canyons near Ningaloo. Additionally, up to 30 new underwater species were made by researchers from the Western Australian Museum aboard Schmidt Ocean Institute's research vessel Falkor.

The discovery of the massive gelatinous string siphonophore—a floating colony of tiny individual zooids that clone themselves thousands of times into specialized bodies that string together to work as a team—was just one of the unique finds among some of the deepest fish and marine invertebrates ever recorded for Western Australia. Scientists from the Western Australian Museum, led by Chief Scientist Dr. Nerida Wilson, were joined by researchers from Curtin University, Geoscience Australia and Scripps Institution of Oceanography in exploring the Ningaloo Canyons in the Indian Ocean. Using an underwater robot, ROV SuBastian, they completed 20 dives at depths of up to 4,500 meters over 181 hours of exploration.

During the expedition, scientists collected the first giant hydroids in Australia, discovered large communities of glass sponges in Cape Range Canyon, and observed for the first time in Western Australia the bioluminescent Taning's octopus squid, long-tailed sea cucumber, and a number of other molluscs, barnacle and squat lobster species. Some of the species collected will be exhibited at the Western Australian Museum.

The team also found the largest specimen of the giant siphonophore Apolemia ever recorded—video of which was posted on Schmidt Ocean Institute's Twitter account. "We suspected these deep sea areas would be diverse but we have been blown away by the significance of what we have seen," Wilson said. Added Dr. Lisa Kirkendale, head of aquatic zoology at the Western Australian Museum and co-principal investigatorI, "These specimens represent so many extensions in depth and range records for so many species, and will form an important new part of WA Museum collections."

Check out this beautiful giant siphonophore Apolemia recorded on #NingalooCanyons expedition. It seems likely that this specimen is the largest ever recorded, and in strange UFO-like feeding posture. Credit: Schmidt Ocean Institute

The expedition is part of Schmidt Ocean Institute's year-long initiative in Australia and the Pacific to conduct a number of science and engineering expeditions with teams of scientists and researchers from around the world. Using the underwater robot SuBastian, scientists for the first time are able to explore deep sea canyons and coral reefs around Australia that have never been seen before. The footage and samples collected from the oceans that surround Australia will have important implications for the sustainability and protection of these underwater ecosystems—and for similar habitats worldwide that are in peril because of rising ocean temperatures and other environmental threats.

Owned and operated by Schmidt Ocean Institute, a philanthropic non-profit established by Eric and Wendy Schmidt in 2009, Falkor is the only year-round seagoing philanthropic research vessel in the world. The vessel is equipped with a state-of-the-art 4,500 meter-capable underwater robotic system, ROV SuBastian, that was used to visually explore and collect samples from critical deep ocean areas that had not been explored before. The ship and ROV are both made available to the international science community at no cost, and the scientists agree to make their discoveries publicly available. The collection data for these specimens will be made publicly available.

"There is so much we don't know about the deep sea, and there are countless species never before seen," said Wendy Schmidt, co-founder of Schmidt Ocean Institute. "Our planet is deeply interconnected—what happens in the deep sea impacts life on land—and vice versa. This research is vital to advance our understanding of that connection—and the importance of protecting these fragile ecosystems. The Ningaloo Canyons are just one of many vast underwater wonders we are about to discover that can help us better understand our planet."

The science completed will allow the research team to formally describe many of the new species of animals that were found, develop ROV methodology for monitoring Marine Parks in Australia and screen deep water samples for environmental DNA in the Indian Ocean. The ROV SuBastian dives were livestreamed and are available in perpetuity on Schmidt Ocean Institute's YouTube page, including video highlights, making the incredible diversity in the Ningaloo region available for the public to explore. The footage and specimens collected are important records within the Gascoyne Marine Park, serving as a permanent record of biodiversity in the canyons to build on in the future.

"Ongoing scientific exploration is vital to the effective management of our marine parks," said Dr. James Findlay, director of Australia's National Parks, who has been closely following the Falkor expedition, "and we are committed to partnering with other agencies to record and monitor these precious places.

Deep-sea coral gardens discovered in canyons off Australia's South West

Provided by Schmidt Ocean Institute

LA REVUE GAUCHE - Left Comment