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Tuesday, 31 March 2020

Too much salt weakens the immune system


A diet rich in salt weakens the antibacterial immune defense

A high-salt diet is not only bad for one's blood pressure, but also for the immune system. This is the conclusion of a current study under the leadership of the University Hospital Bonn. Mice fed a high-salt diet were found to suffer from much more severe bacterial infections. Human volunteers who consumed an additional six grams of salt per day also showed pronounced immune deficiencies. This amount corresponds to the salt content of two fast food meals. The results are published in the journal "Science Translational Medicine".

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Five grams a day, no more: This is the maximum amount of salt that adults should consume according to the recommendations of the World Health Organization (WHO). It corresponds approximately to one level teaspoon. In reality, however, many Germans exceed this limit considerably: Figures from the Robert Koch Institute suggest that on average men consume ten, women more than eight grams a day.



This means that we reach for the salt shaker much more than is good for us. After all, sodium chloride, which is its chemical name, raises blood pressure and thereby increases the risk of heart attack or stroke. But not only that: "We have now been able to prove for the first time that excessive salt intake also significantly weakens an important arm of the immune system," explains Prof. Dr. Christian Kurts from the Institute of Experimental Immunology at the University of Bonn.

Graph showing the level of bacteria present in the spleen in the case of an infection with L. monocytogenes . In black for a low salt diet, and in blue for a high salt diet. Credits: Katarzyna Jobin et al. 2020


This finding is unexpected, as some studies point in the opposite direction. For example, infections with certain skin parasites in laboratory animals heal significantly faster if these consume a high-salt diet: The macrophages, which are immune cells that attack, eat and digest parasites, are particularly active in the presence of salt. Several physicians concluded from this observation that sodium chloride has a generally immune-enhancing effect.

The skin serves as a salt reservoir

"Our results show that this generalization is not accurate," emphasizes Katarzyna Jobin, lead author of the study, who has since transferred to the University of Würzburg. There are two reasons for this: Firstly, the body keeps the salt concentration in the blood and in the various organs largely constant. Otherwise important biological processes would be impaired. The only major exception is the skin: It functions as a salt reservoir of the body. This is why the additional intake of sodium chloride works so well for some skin diseases.

However, other parts of the body are not exposed to the additional salt consumed with food. Instead, it is filtered out by the kidneys and excreted in the urine. And this is where the second mechanism comes into play: The kidneys have a sodium chloride sensor that activates the salt excretion function. As an undesirable side effect, however, this sensor also causes so-called glucocorticoids to accumulate in the body. And these in turn inhibit the function of granulocytes, the most common type of immune cell in the blood.

Charts showing the levels of hormones and urea in the body for a low-salt diet (black) and a high-salt diet (blue). Credits: Katarzyna Jobin et al. 2020


Granulocytes, like macrophages, are scavenger cells. However, they do not attack parasites, but mainly bacteria. If they do not do this to a sufficient degree, infections proceed much more severely. "We were able to show this in mice with a listeria infection," explains Dr. Jobin. "We had previously put some of them on a high-salt diet. In the spleen and liver of these animals we counted 100 to 1,000 times the number of disease-causing pathogens." Listeria are bacteria that are found for instance in contaminated food and can cause fever, vomiting and sepsis. Urinary tract infections also healed much more slowly in laboratory mice fed a high-salt diet.

Sodium chloride also appears to have a negative effect on the human immune system. "We examined volunteers who consumed six grams of salt in addition to their daily intake," says Prof. Kurts. "This is roughly the amount contained in two fast food meals, i.e. two burgers and two portions of French fries." After one week, the scientists took blood from their subjects and examined the granulocytes. The immune cells coped much worse with bacteria after the test subjects had started to eat a high-salt diet.



In human volunteers, the excessive salt intake also resulted in increased glucocorticoid levels. That this inhibits the immune system is not surprising: The best-known glucocorticoid cortisone is traditionally used to suppress inflammation. "Only through investigations in an entire organism were we able to uncover the complex control circuits that lead from salt intake to this immunodeficiency," stresses Kurts. "Our work therefore also illustrates the limitations of experiments purely with cell cultures."


Bibliography:

Katarzyna Jobin, Natascha E. Stumpf, Sebastian Schwab, Melanie Eichler, Patrick Neubert, Manfred Rauh, Marek Adamowski, Olena Babyak, Daniel Hinze, Sugirthan Sivalingam, Christina K. Weisheit, Katharina Hochheiser, Susanne Schmidt, Mirjam Meissner, Natalio Garbi, Zeinab Abdullah, Ulrich Wenzel, Michael Hölzel, Jonathan Jantsch and Christian Kurts.

A high-salt diet compromises antibacterial neutrophil responses through hormonal perturbation.

Science Translational Medicine, 2020

DOI: 10.1126/scitranslmed.aay3850

Friday, 27 March 2020

As the ocean warms, marine species relocate toward the poles


Since pre-industrial times, the world's oceans have warmed by an average of one degree Celsius (1°C). Now researchers report in Current Biology on March 26th that those rising temperatures have led to widespread changes in the population sizes of marine species. The researchers found a general pattern of species having increasing numbers on their poleward sides and losses toward the equator.

"The main surprise is how pervasive the effects were," says senior author Martin Genner, an evolutionary ecologist at the University of Bristol. "We found the same trend across all groups of marine life we looked at, from plankton to marine invertebrates, and from fish to seabirds."

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The new study builds on earlier evidence for a prevailing effect of climate change on the distributions, abundance, and seasonality of marine species. Based on those findings, Genner's team reasoned that marine species should be doing well at the leading (poleward) edge of their ranges but poorly at their trailing (equatorward) side. They also realized that existing databases of global species distributions could be used to test this hypothesis.

Based on a thorough search of available data in the literature, the researchers now report on a global analysis of abundance trends for 304 widely distributed marine species over the last century. The results show that -- just as predicted -- abundance increases have been most prominent where sampling has taken place at the poleward side of species ranges, while abundance declines have been most prominent where sampling has taken place at the equatorward side of species ranges.



The findings show that large-scale changes in the abundance of species are well underway. They also suggest that marine species haven't managed to adapt to warmer conditions. The researchers therefore suggest that projected sea temperature increases of up to 1.5°C over pre-industrial levels by 2050 will continue to drive the latitudinal abundance shifts in marine species, including those of importance for coastal livelihoods.

"This matters because it means that climate change is not only leading to abundance changes, but intrinsically affecting the performance of species locally," Genner says. "We see species such as Emperor penguin becoming less abundant as water becomes too warm at their equatorward edge, and we see some fish such as European seabass thriving at their poleward edge where historically they were uncommon."

The findings show that climate change is affecting marine species in a highly consistent and non-trivial way. "While some marine life may benefit as the ocean warms, the findings point toward a future in which we will also see continued loss of marine life," Genner says.

The long-term data included in the study primarily represent the most well-studied regions of the world. The researchers say that more work is needed to understand how climate change has affected marine life in all regions of the world in greater detail.

"We aim to get a better understanding of precisely how marine climate change drives abundance shifts," Genner says. "Is this mainly related to the physiological limits of the species, or instead due to changes in the species with which they interact?"



The work was supported by the Natural Environment Research Council and the UK Government Office for Science.


Bibliography:

Reuben A. Hastings, Louise A. Rutterford, Jennifer J. Freer, Rupert A. Collins, Stephen D. Simpson, Martin J. Genner.

Climate Change Drives Poleward Increases and Equatorward Declines in Marine Species. 

Current Biology, 2020;

DOI: 10.1016/j.cub.2020.02.043

New mathematical model can more effectively track epidemics



As COVID-19 spreads worldwide, leaders are relying on mathematical models to make public health and economic decisions.

A new model developed by Princeton and Carnegie Mellon researchers improves tracking of epidemics by accounting for mutations in diseases. Now, the researchers are working to apply their model to allow leaders to evaluate the effects of countermeasures to epidemics before they deploy them.

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“We want to be able to consider interventions like quarantines, isolating people, etc., and then see how they affect an epidemic’s spread when the pathogen is mutating as it spreads,” said H. Vincent Poor, one of the researchers on this study and Princeton’s interim dean of engineering.

The models currently used to track epidemics use data from doctors and health workers to make predictions about a disease’s progression. Poor, the Michael Henry Strater University Professor of Electrical Engineering, said the model most widely used today is not designed to account for changes in the disease being tracked. This inability to account for changes in the disease can make it more difficult for leaders to counter a disease’s spread. Knowing how a mutation could affect transmission or virulence could help leaders decide when to institute isolation orders or dispatch additional resources to an area.



“In reality, these are physical things, but in this model, they are abstracted into parameters that can help us more easily understand the effects of policies and of mutations,” Poor said.

If the researchers can correctly account for measures to counter the spread of disease, they could give leaders critical insights into the best steps they could take in the face of pandemics. The researchers are building on work published March 17 in the Proceedings of the National Academy of Sciences. In that article, they describe how their model is able to track changes in epidemic spread caused by mutation of a disease organism. The researchers are now working to adapt the model to account for public health measures taken to stem an epidemic as well.

The researchers’ work stems from their examination of the movement of information through social networks, which has remarkable similarities to the spread of biological infections. Notably, the spread of information is affected by slight changes in the information itself. If something becomes slightly more exciting to recipients, for example, they might be more likely to pass it along or to pass it along to a wider group of people. By modeling such variations, one can see how changes in the message change its target audience.

“The spread of a rumor or of information through a network is very similar to the spread of a virus through a population,” Poor said. “Different pieces of information have different transmission rates. Our model allows us to consider changes to information as it spreads through the network and how those changes affect the spread.”

“Our model is agnostic with regard to the physical network of connectivity among individuals,” said Poor, an expert in the field of information theory whose work has helped establish modern cellphone networks. “The information is being abstracted into graphs of connected nodes; the nodes might be information sources or they might be potential sources of infection.”



Obtaining accurate information is extremely difficult during an ongoing pandemic when circumstances shift daily, as we have seen with the COVID-19 virus. “It’s like a wildfire. You can’t always wait until you collect data to make decisions — having a model can help fill this void,” Poor said.

 “Hopefully, this model could give leaders another tool to better understand the reasons why, for example, the COVID-19 virus is spreading so much more rapidly than predicted, and thereby help them deploy more effective and timely countermeasures,” Poor said.


Bibliography:

Rashad Eletreby, Yong Zhuang, Kathleen M. Carley, Osman Yağan, H. Vincent Poor.

The effects of evolutionary adaptations on spreading processes in complex networks. 

Proceedings of the National Academy of Sciences, 2020; 117 (11): 5664

DOI: 10.1073/pnas.1918529117

Tuesday, 24 March 2020

Ancestor of all animals identified in Australian fossils


A team led by UC Riverside geologists has discovered the first ancestor on the family tree that contains most familiar animals today, including humans.

The tiny, wormlike creature, named Ikaria wariootia, is the earliest bilaterian, or organism with a front and back, two symmetrical sides, and openings at either end connected by a gut. The paper is published today in Proceedings of the National Academy of Sciences.

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The earliest multicellular organisms, such as sponges and algal mats, had variable shapes. Collectively known as the Ediacaran Biota, this group contains the oldest fossils of complex, multicellular organisms. However, most of these are not directly related to animals around today, including lily pad-shaped creatures known as Dickinsonia that lack basic features of most animals, such as a mouth or gut.

The development of bilateral symmetry was a critical step in the evolution of animal life, giving organisms the ability to move purposefully and a common, yet successful way to organize their bodies. A multitude of animals, from worms to insects to dinosaurs to humans, are organized around this same basic bilaterian body plan.



Evolutionary biologists studying the genetics of modern animals predicted the oldest ancestor of all bilaterians would have been simple and small, with rudimentary sensory organs. Preserving and identifying the fossilized remains of such an animal was thought to be difficult, if not impossible.

For 15 years, scientists agreed that fossilized burrows found in 555 million-year-old Ediacaran Period deposits in Nilpena, South Australia, were made by bilaterians. But there was no sign of the creature that made the burrows, leaving scientists with nothing but speculation.

Scott Evans, a recent doctoral graduate from UC Riverside; and Mary Droser, a professor of geology, noticed miniscule, oval impressions near some of these burrows. With funding from a NASA exobiology grant, they used a three-dimensional laser scanner that revealed the regular, consistent shape of a cylindrical body with a distinct head and tail and faintly grooved musculature. The animal ranged between 2-7 millimeters long and about 1-2.5 millimeters wide, with the largest the size and shape of a grain of rice -- just the right size to have made the burrows.

"We thought these animals should have existed during this interval, but always understood they would be difficult to recognize," Evans said. "Once we had the 3D scans, we knew that we had made an important discovery."

A 3D laser scan of an Ikaria wariootia impression. (Droser Lab/UCR)


The researchers, who include Ian Hughes of UC San Diego and James Gehling of the South Australia Museum, describe Ikaria wariootia, named to acknowledge the original custodians of the land. The genus name comes from Ikara, which means "meeting place" in the Adnyamathanha language. It's the Adnyamathanha name for a grouping of mountains known in English as Wilpena Pound. The species name comes from Warioota Creek, which runs from the Flinders Ranges to Nilpena Station.

"Burrows of Ikaria occur lower than anything else. It's the oldest fossil we get with this type of complexity," Droser said. "Dickinsonia and other big things were probably evolutionary dead ends. We knew that we also had lots of little things and thought these might have been the early bilaterians that we were looking for."

In spite of its relatively simple shape, Ikaria was complex compared to other fossils from this period. It burrowed in thin layers of well-oxygenated sand on the ocean floor in search of organic matter, indicating rudimentary sensory abilities. The depth and curvature of Ikaria represent clearly distinct front and rear ends, supporting the directed movement found in the burrows.



The burrows also preserve crosswise, "V"-shaped ridges, suggesting Ikaria moved by contracting muscles across its body like a worm, known as peristaltic locomotion. Evidence of sediment displacement in the burrows and signs the organism fed on buried organic matter reveal Ikaria probably had a mouth, anus, and gut.

"This is what evolutionary biologists predicted," Droser said. "It's really exciting that what we have found lines up so neatly with their prediction."


Bibliography:

Scott D. Evans, Ian V. Hughes, James G. Gehling, and Mary L. Droser.

Discovery of the oldest bilaterian from the Ediacaran of South Australia.

PNAS, March 23, 2020

DOI: 10.1073/pnas.2001045117

Monday, 23 March 2020

Some Blood Types May Be Slightly More Susceptible to COVID-19, Paper Suggests


As governments take increasingly stringent containment measures to stop the spread of the coronavirus, researchers are still trying to better understand the dynamics of the latter. Recently, a team of Chinese immunologists suggested that not all blood groups were equal in the face of the virus. Indeed, type A would be more likely to contract the infection, while group O would be less. While these results are interesting for a better understanding of SARS-CoV-2, they have not yet been the subject of a peer-review procedure and should therefore be taken with caution.

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The study was undertaken by Chinese researchers and focused on 2,173 patients with COVID-19 from three hospitals in Wuhan and Shenzhen. The team looked at the distribution of blood types in the normal population in each area, and then compared it to their sample of patients with the virus, again in each area.

"Meta-analyses on the pooled data showed that blood group A had a significantly higher risk for COVID-19 compared with non-A blood groups," the researchers write in their paper. "Whereas blood group O had a significantly lower risk for the infectious disease compared with non-O blood groups."



Blood groups potentially affected differently by SARS-CoV-2 coronavirus

But the paper also clearly states that although the results were significant, it's not an all-or-nothing result.

As per the study, the normal population in Wuhan has a blood type distribution of 31 percent type A, 24 percent type B, 9 percent type AB, and 34 percent type O. Those with the virus, by comparison, were distributed as follows: 38 percent type A, 26 percent type B, 10 percent type AB, and 25 percent type O. Similar differences were observed in Shenzhen.

The different blood groups and their antigenic structure. Credits: Maxicours

As you can see, the percentages between the normal population and those with the virus have some differences - but it doesn't mean that people with type O blood type are immune; and not everyone who gets the virus is going to be type A. Far from it.

So, these relatively small differences, if replicated in studies with larger data pools, could lead to slight changes in the way we manage the spread of the disease; but even so, it probably won't change anything about the way we individually should be trying to limit the spread of the virus.

So, that's the low-down on the study. But this raises another fascinating topic - how our blood types can change the way we are affected by certain viruses is interesting in itself.

Norovirus is a stomach flu, and people will usually be infected through the digestive system. Those antigens on our blood cells are also on the surface of cells that line the intestine, and norovirus requires certain antigens to latch on to.

"This difference in susceptibility [to norovirus] has an interesting consequence," microbiologist Patricia Foster writes for The Conversation. "When an outbreak occurs, for example, on a cruise ship, roughly a third of the people may escape infection.

"Because they do not know the underlying reason for their resistance, I think spared people engage in magical thinking – for example, 'I didn't get sick because I drank a lot of grape juice'. Of course, these mythical evasive techniques will not work if the next outbreak is a strain to which the individual is susceptible."

So, how might the new coronavirus exploit our different blood types? At this point, we simply don't know.

The authors of the blood group paper uploaded to medRxiv aren't sure, but they suggest that maybe it has to do with the anti-A antibodies that both type B and type O have. That's just a hypothesis for now, and until we find out more, don't take it as gospel.



But it is a great example of how we are learning new information about the virus every single day. There's currently a vaccine being trialled in humans; many are doing everything they can to flatten the curve; and while the pandemic is stopping the world in its tracks, communities are swapping supplies and helping those in need.


Bibliography:

Relationship between the ABO Blood Group and the COVID-19 Susceptibility

Jiao Zhao, Yan Yang, Han-Ping Huang, Dong Li, Dong-Feng Gu, Xiang-Feng Lu, Zheng Zhang, Lei Liu, Ting Liu, Yu-Kun Liu, Yun-Jiao He, Bin Sun, Mei-Lan Wei, Guang-Yu Yang, Xinghuan Wang, Li Zhang, Xiao-Yang Zhou, Ming-Zhao Xing, Peng George Wang

doi: https://doi.org/10.1101/2020.03.11.20031096

Saturday, 21 March 2020

Study reveals how long COVID-19 remains infectious on cardboard, metal and plastic


The virus that causes COVID-19 remains for several hours to days on surfaces and in aerosols, a new study published in the New England Journal of Medicine found.

The study suggests that people may acquire the coronavirus through the air and after touching contaminated objects. Scientists discovered the virus is detectable for up to three hours in aerosols, up to four hours on copper, up to 24 hours on cardboard and up to two to three days on plastic and stainless steel.

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"This virus is quite transmissible through relatively casual contact, making this pathogen very hard to contain," said James Lloyd-Smith, a co-author of the study and a UCLA professor of ecology and evolutionary biology. "If you're touching items that someone else has recently handled, be aware they could be contaminated and wash your hands."



The study attempted to mimic the virus being deposited onto everyday surfaces in a household or hospital setting by an infected person through coughing or touching objects, for example. The scientists then investigated how long the virus remained infectious on these surfaces.

The study's authors are from UCLA, the National Institutes of Health's National Institute of Allergy and Infectious Diseases, the Centers for Disease Control and Prevention, and Princeton University. They include Amandine Gamble, a UCLA postdoctoral researcher in Lloyd-Smith's laboratory.

As shown in Panel A, the titer of aerosolized viable virus is expressed in 50% tissue-culture infectious dose (TCID50) per liter of air. Viruses were applied to copper, cardboard, stainless steel, and plastic maintained at 21 to 23°C and 40% relative humidity over 7 days. The titer of viable virus is expressed as TCID50 per milliliter of collection medium. All samples were quantified by end-point titration on Vero E6 cells. Plots show the means and standard errors ( bars) across three replicates. As shown in Panel B, regression plots indicate the predicted decay of virus titer over time; the titer is plotted on a logarithmic scale. Points show measured titers and are slightly jittered (i.e., they show small rapid variations in the amplitude or timing of a waveform arising from fluctuations) along the time axis to avoid overplotting. Lines are random draws from the joint posterior distribution of the exponential decay rate (negative of the slope) and intercept (initial virus titer) to show the range of possible decay patterns for each experimental condition. There were 150 lines per panel, including 50 lines from each plotted replicate. As shown in Panel C, violin plots indicate posterior distribution for the half-life of viable virus based on the estimated exponential decay rates of the virus titer. The dots indicate the posterior median estimates, and the black lines indicate a 95% credible interval. Experimental conditions are ordered according to the posterior median half-life of SARS-CoV-2. The dashed lines indicate the limit of detection, which was 3.33×100.5 TCID50 per liter of air for aerosols, 100.5 TCID50 per milliliter of medium for plastic, steel, and cardboard, and 101.5 TCID50 per milliliter of medium for copper.


In February, Lloyd-Smith and colleagues reported in the journal eLife that screening travelers for COVID-19 is not very effective. People infected with the virus -- officially named SARS-CoV-2 -- may be spreading the virus without knowing they have it or before symptoms appear. Lloyd-Smith said the biology and epidemiology of the virus make infection extremely difficult to detect in its early stages because the majority of cases show no symptoms for five days or longer after exposure.

"Many people won't have developed symptoms yet," Lloyd-Smith said. "Based on our earlier analysis of flu pandemic data, many people may not choose to disclose if they do know."

The new study supports guidance from public health professionals to slow the spread of COVID-19:



  • Avoid close contact with people who are sick.

  • Avoid touching your eyes, nose and mouth.

  • Stay home when you are sick.

  • Cover coughs or sneezes with a tissue, and dispose of the tissue in the trash.

  • Clean and disinfect frequently touched objects and surfaces using a household cleaning spray or wipe.


Bibliography:

Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1.

Neeltje van Doremalen, Trenton Bushmaker, Dylan H. Morris, Myndi G. Holbrook, Amandine Gamble, Brandi N. Williamson, Azaibi Tamin, Jennifer L. Harcourt, Natalie J. Thornburg, Susan I. Gerber, James O. Lloyd-Smith, Emmie de Wit, Vincent J. Munster.

New England Journal of Medicine, 2020;

DOI: 10.1056/NEJMc2004973

Friday, 20 March 2020

Coronavirus spreads quickly and sometimes before people have symptoms, study finds


Infectious disease researchers at The University of Texas at Austin studying the novel coronavirus were able to identify how quickly the virus can spread, a factor that may help public health officials in their efforts at containment. They found that time between cases in a chain of transmission is less than a week and that more than 10% of patients are infected by somebody who has the virus but does not yet have symptoms.

In the paper in press with the journal Emerging Infectious Diseases, a team of scientists from the United States, France, China and Hong Kong were able to calculate what's called the serial interval of the virus. To measure serial interval, scientists look at the time it takes for symptoms to appear in two people with the virus: the person who infects another, and the infected second person.

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Researchers found that the average serial interval for the novel coronavirus in China was approximately four days. This also is among the first studies to estimate the rate of asymptomatic transmission.

The speed of an epidemic depends on two things -- how many people each case infects and how long it takes for infection between people to spread. The first quantity is called the reproduction number; the second is the serial interval. The short serial interval of COVID-19 means emerging outbreaks will grow quickly and could be difficult to stop, the researchers said.

"Ebola, with a serial interval of several weeks, is much easier to contain than influenza, with a serial interval of only a few days. Public health responders to Ebola outbreaks have much more time to identify and isolate cases before they infect others," said Lauren Ancel Meyers, a professor of integrative biology at UT Austin. "The data suggest that this coronavirus may spread like the flu. That means we need to move quickly and aggressively to curb the emerging threat."



Meyers and her team examined more than 450 infection case reports from 93 cities in China and found the strongest evidence yet that people without symptoms must be transmitting the virus, known as pre-symptomatic transmission. According to the paper, more than 1 in 10 infections were from people who had the virus but did not yet feel sick.

Previously, researchers had some uncertainty about asymptomatic transmission with the coronavirus. This new evidence could provide guidance to public health officials on how to contain the spread of the disease.

"This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted," Meyers said. "Asymptomatic transmission definitely makes containment more difficult."

Meyers pointed out that with hundreds of new cases emerging around the world every day, the data may offer a different picture over time. Infection case reports are based on people's memories of where they went and whom they had contact with. If health officials move quickly to isolate patients, that may also skew the data.

"Our findings are corroborated by instances of silent transmission and rising case counts in hundreds of cities worldwide," Meyers said. "This tells us that COVID-19 outbreaks can be elusive and require extreme measures."

Zhanwei Du of The University of Texas at Austin, Lin Wang of the Institut Pasteur in Paris, Xiaoke Xu of Dalian Minzu University, Ye Wu of Beijing Normal University and Benjamin J. Cowling of Hong Kong University also contributed to the research. Lauren Ancel Meyers holds the Denton A. Cooley Centennial Professorship in Zoology at The University of Texas at Austin.



The research was funded by the U.S. National Institutes of Health and the National Natural Science Foundation of China.


Bibliography:

Serial Interval of COVID-19 from Publicly Reported Confirmed Cases.

Zhanwei Du, Xiaoke Xu, Ye Wu, Lin Wang, Benjamin J. Cowling, Lauren Ancel Meyers.

Emerging Infectious Diseases, April 2020;

DOI: 10.3201/eid2606.200357

COVID-19: pandemic has reduced air pollution in several countries


As the spread of the SARS-CoV-2 coronavirus continues to expand, the pandemic has begun to show positive trends worldwide. This is particularly the case of air pollution. According to the latest observation results from the ESA Copernicus satellite, the containment measures would have made it possible to reduce carbon dioxide and nitrogen dioxide pollution significantly. And according to researcher Mashall Burke, the number of lives indirectly saved by this reduction in pollution could far exceed the human losses due to the virus.

Back on March 8, Stanford University environmental resource economist Marshall Burke did some back-of-the-envelope calculations about the recent air pollution drop over parts of China and potential lives saved, posting it on a global food, environment and economic dynamics blog, G-FEED.

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The situation has continued to unfold since then, so those numbers won't stay current for long; but according to Burke, even conservatively, it's very likely that the lives saved locally from the reduction in pollution exceed COVID-19 deaths in China.

"Given the huge amount of evidence that breathing dirty air contributes heavily to premature mortality, a natural - if admittedly strange - question is whether the lives saved from this reduction in pollution caused by economic disruption from COVID-19 exceeds the death toll from the virus itself," Burke writes.



Pollution reduction in China: lives saved would exceed losses due to virus

The two months of pollution reduction, Burke calculates, has probably saved the lives of 4,000 children under 5 and 73,000 adults over 70 in China. That's significantly more than the current global death toll from the virus itself.

Although this might seem a little surprising, it's something we've known about for quite a long time. Earlier this month, research suggested that air pollution costs us three years, on average, off our global life expectancy.

Loss of average life expectancy according to different causes of death for the year 2015. Air pollution arrives at the top of the podium with approximately 3 years of life expectancy lost, before smoking. Credits: Jos Lelieveld et al. 2020

"It is remarkable that both the number of deaths and the loss in life expectancy from air pollution rival the effect of tobacco smoking and are much higher than other causes of death," physicist Jos Lelieveld from the Cyprus Institute in Nicosia stated at the time.

"Air pollution exceeds malaria as a global cause of premature death by a factor of 19; it exceeds violence by a factor of 16, HIV/AIDS by a factor of 9, alcohol by a factor of 45, and drug abuse by a factor of 60."

But Burke's analysis was just using data from China, and was completed before there was more information about how COVID-19 has affected the rest of the world.

With the second largest number of cases occurring in Italy, and the country putting in place strict quarantine measures, satellite data over northern Italy have now shown a large drop in air pollution - specifically nitrogen dioxide, a gas mainly emitted by cars, trucks, power plants and some industrial plants.

A net reduction in nitrogen dioxide pollution in Italy

"The decline in nitrogen dioxide emissions over the Po Valley in northern Italy is particularly evident," explains Claus Zehner, ESA's Copernicus Sentinel-5P mission manager.

"Although there could be slight variations in the data due to cloud cover and changing weather, we are very confident that the reduction in emissions that we can see, coincides with the lock-down in Italy causing less traffic and industrial activities."

For now, we don't have peer-reviewed studies measuring the true health impact reduced emissions will bring, but given what we know about the dangers of widespread air pollution, it's likely that there will be a direct benefit in the shape of fewer pollution-related deaths.



Even such a tiny silver lining can hardly make up for the devastation of the COVID-19 pandemic. But these preliminary numbers demonstrate that this global health disaster is an opportunity to assess - which aspects of modern life are absolutely necessary, and what positive changes might be possible if we change our habits on a global scale.

This ESA video shows the reduction of nitrogen dioxide emissions in Italy:



Source Source 2

Monday, 16 March 2020

Engineers crack 58-year-old puzzle on way to quantum breakthrough


Magnetic nuclear resonance makes it possible to control atomic nuclear spins via the application of a magnetic field. This technique is very often used in many fields such as medicine (MRI), chemistry (characterization of chemical species) or geology. But in 1961, Nobel Prize winner Nicolaas Bloembergen suggested that it is also possible to control nuclear spins via an electric field. About 59 years later, a team of engineers finally confirmed, by serendipity, the existence of an electrical nuclear resonance. A result that will allow the development of much more efficient quantum electronics.

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A happy accident in the laboratory has led to a breakthrough discovery that not only solved a problem that stood for more than half a century, but has major implications for the development of quantum computers and sensors.

In a study published today in Nature, a team of engineers at UNSW Sydney has done what a celebrated scientist first suggested in 1961 was possible, but has eluded everyone since: controlling the nucleus of a single atom using only electric fields.

“This discovery means that we now have a pathway to build quantum computers using single-atom spins without the need for any oscillating magnetic field for their operation,” says UNSW’s Scientia Professor of Quantum Engineering Andrea Morello. “Moreover, we can use these nuclei as exquisitely precise sensors of electric and magnetic fields, or to answer fundamental questions in quantum science.”



More precise atomic control thanks to electrical nuclear resonance

That a nuclear spin can be controlled with electric, instead of magnetic fields, has far-reaching consequences. Generating magnetic fields requires large coils and high currents, while the laws of physics dictate that it is difficult to confine magnetic fields to very small spaces – they tend to have a wide area of influence. Electric fields, on the other hand, can be produced at the tip of a tiny electrode, and they fall off very sharply away from the tip. This will make control of individual atoms placed in nanoelectronic devices much easier.

Professor Morello says the discovery shakes up the paradigm of nuclear magnetic resonance, a widely used technique in fields as disparate as medicine, chemistry, or mining.

“Nuclear magnetic resonance is one of the most widespread techniques in modern physics, chemistry, and even medicine or mining,” he says. “Doctors use it to see inside a patient’s body in great detail while mining companies use it to analyse rock samples. This all works extremely well, but for certain applications, the need to use magnetic fields to control and detect the nuclei can be a disadvantage.”

Diagram explaining the operation of nuclear magnetic resonance on the spin of an atomic nucleus. Credits: HUJI

Professor Morello uses the analogy of a billiard table to explain the difference between controlling nuclear spins with magnetic and electric fields.

“Performing magnetic resonance is like trying to move a particular ball on a billiard table by lifting and shaking the whole table,” he says. “We'll move the intended ball, but we'll also move all the others.

“The breakthrough of electric resonance is like being handed an actual billiards stick to hit the ball exactly where you want it.”

A possibility suggested since 1961

Amazingly, Professor Morello was completely unaware that his team had cracked the longstanding problem of finding a way to control nuclear spins with electric fields, first suggested in 1961 by a pioneer of magnetic resonance and Nobel Laureate, Nicolaas Bloembergen.

“I have worked on spin resonance for 20 years of my life, but honestly, I had never heard of this idea of nuclear electric resonance,” Professor Morello says. “We ‘rediscovered’ this effect by complete accident – it would never have occurred to me to look for it. The whole field of nuclear electric resonance has been almost dormant for more than half a century, after the first attempts to demonstrate it proved too challenging.”

A discovery made entirely by chance

The researchers had originally set out to perform nuclear magnetic resonance on a single atom of antimony – an element that possesses a large nuclear spin. One of the lead authors of the work, Dr Serwan Asaad, explains: “Our original goal was to explore the boundary between the quantum world and the classical world, set by the chaotic behaviour of the nuclear spin. This was purely a curiosity-driven project, with no application in mind.”

“However, once we started the experiment, we realised that something was wrong. The nucleus behaved very strangely, refusing to respond at certain frequencies, but showing a strong response at others,” recalls Dr Vincent Mourik, also a lead author on the paper.

“This puzzled us for a while, until we had a ‘eureka moment’ and realised that we were doing electric resonance instead of magnetic resonance.”

Antenna and antimony atom: the unexpected generation of an electric field

Dr Asaad continued: “What happened is that we fabricated a device containing an antimony atom and a special antenna, optimized to create a high-frequency magnetic field to control the nucleus of the atom. Our experiment demands this magnetic field to be quite strong, so we applied a lot of power to the antenna, and we blew it up!”


Diagram explaining how the electric field allows the control of an atomic nuclear spin. (A): Valence charge density near the Sb + atom (gold) and its 16 closest Si atoms (black), with an isosurface charge density (red). (B): Deformation displacing the Si atoms and the covalent bonds surrounding the nucleus, creating an EFG which results in a quadrupole shift. (D): Electric fields applied via a superposition of voltages distort the charge distribution, which leads to both linear frequency shifts (LQSE) and coherent spin transitions (NER). Credits: Serwan Asaad, et al. 2020

“Normally, with smaller nuclei like phosphorus, when you blow up the antenna it’s ‘game over’ and you have to throw away the device,” says Dr Mourik.

“But with the antimony nucleus, the experiment continued to work. It turns out that after the damage, the antenna was creating a strong electric field instead of a magnetic field. So we ‘rediscovered’ nuclear electric resonance.”

Towards more precise and efficient quantum electronics

After demonstrating the ability to control the nucleus with electric fields, the researchers used sophisticated computer modelling to understand how exactly the electric field influences the spin of the nucleus. This effort highlighted that nuclear electric resonance is a truly local, microscopic phenomenon: the electric field distorts the atomic bonds around the nucleus, causing it to reorient itself.



“This landmark result will open up a treasure trove of discoveries and applications,” says Professor Morello. “The system we created has enough complexity to study how the classical world we experience every day emerges from the quantum realm. Moreover, we can use its quantum complexity to build sensors of electromagnetic fields with vastly improved sensitivity. And all this, in a simple electronic device made in silicon, controlled with small voltages applied to a metal electrode.”



Bibliography:

Coherent electrical control of a single high-spin nucleus in silicon

Serwan Asaad, Vincent Mourik, Benjamin Joecker, Mark A. I. Johnson, Andrew D. Baczewski, Hannes R. Firgau, Mateusz T. Mądzik, Vivien Schmitt, Jarryd J. Pla, Fay E. Hudson, Kohei M. Itoh, Jeffrey C. McCallum, Andrew S. Dzurak, Arne Laucht & Andrea Morello

Nature 579, 205–209 (2020).

https://doi.org/10.1038/s41586-020-2057-7

Sunday, 15 March 2020

Researchers have found a way to efficiently produce hydrogen using rust and a light source.


Scientists identify a new and efficient way of producing hydrogen from organic waste solution using a catalyst derived from -- of all things -- rust

Production of hydrogen fuel is a key goal towards the development of sustainable energy practices, but this process does not have feasible techniques yet. A team of Japanese scientists from Tokyo University of Science, led by Prof Ken-ichi Katsumata, have identified a novel technique of using rust and light to speed up hydrogen production from organic waste solution, a finding that can revolutionize the clean energy industry.

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In today's narrative of climate change, pollution, and diminishing resources, one fuel could be a game-changer within the energy industry: hydrogen. When burned in a combustion engine or in an electrical power-plant, hydrogen fuel produces only water-making it far cleaner than our current fossil fuels. With no toxic gas production, no contribution to climate change, and no smog, hydrogen may be the answer to a future of cleaner energy, so why is it not more widely used?



There are two reasons for this. First, hydrogen is highly flammable and leaks very easily from storage tanks, causing potential explosion hazards during storage and transport. Second, although pure hydrogen occurs naturally on Earth, it is not found in quantities sufficient for cost-effective utilization. Hydrogen atoms must be extracted from molecules like methane or water, which requires a large amount of energy. Although several techniques exist to produce hydrogen fuel, scientists are yet to make this process "efficient" enough to make hydrogen a commercially competitive fuel on the energy market. Until this is achieved, fossil fuels will probably continue to dominate the industry.

For decades, scientists have been working towards a cheap, efficient, and safe way to produce hydrogen fuel. One of the most promising methods to achieve this is through solar-driven processes, using light to speed up (or "catalyze") the reaction to split water molecules into oxygen and hydrogen gas. In the 1970s, two scientists described the Honda-Fujishima effect, which uses titanium dioxide as a photocatalyst in hydrogen production. Building on this research, a team of Japanese researchers led by Prof Ken-ichi Katsumata of Tokyo University of Science, sought to use a cheaper, more readily available semiconductor catalyst for this reaction, with the hope to increase its efficiency even further, reducing the production costs and safety of hydrogen fuel. Their study published in Chemistry: A European Journal indicates that, by using a form of rust called α-FeOOH, hydrogen production under Hg-Xe lamp irradiation can be 25 times higher than titanium dioxide catalyst under the same light.

The experiment conducted by Prof Katsumata and colleagues aimed to address common challenges encountered in using semiconductor catalysts in solar-driven hydrogen production. There are three major obstacles described by the authors. The first is the need for the catalyst material to be suitable for the use of light energy. The second is that most photocatalysts currently used require rare or "noble" metals as cocatalysts, which are expensive and difficult to obtain. The last problem arises from the actual production of hydrogen and oxygen gases. If not separated straight away, the mixture of these two gases can at best reduce the hydrogen fuel output, and at worst, cause an explosion. Therefore, they aimed to find a solution that can not only increase the reaction's efficiency, but also successfully prevent hydrogen and oxygen from re-coupling and creating a potential hazard.

The team identified a promising candidate catalyst in α-FeOOH (or rust) and set out an experiment to evaluate its efficiency for hydrogen production and the optimal experimental conditions for its activation. "We were really surprised at the generation of hydrogen using this catalyst," states Prof Katsumata, "because most of the iron oxides are not known to reduce to hydrogen. Subsequently, we searched for the condition for activating α-FeOOH and found that oxygen was an indispensable factor, which was the second surprise because many studies showed that oxygen suppresses hydrogen production by capturing the excited electrons." The team confirmed the production mechanism of hydrogen from water-methanol solution using a 'gas-chromatography-mass-spectrometry' method, showing that α-FeOOH was 25 times more active than the titanium dioxide catalyst used in previous research, supporting stable hydrogen production for more than 400 hours!



More research will be required to optimize this process. Prof Katsumata elaborates: "The specific function of the oxygen in activating light-induced α-FeOOH has not been unveiled yet. Therefore, exploring the mechanism is the next challenge." For now, these findings of Katsumata and his colleagues represent new advancements in the production of a clean, zero-emissions energy source that will be central to the sustainable societies of the future!


Bibliography:

Hydrogen Production System by Light‐Induced α‐FeOOH Coupled with Photoreduction.

Tetsuya Yamada, Norihiro Suzuki, Kazuya Nakata, Chiaki Terashima, Nobuhiro Matsushita, Kiyoshi Okada, Akira Fujishima, Ken‐ichi Katsumata.

Chemistry – A European Journal, 2020;

DOI: 10.1002/chem.201903642

Saturday, 14 March 2020

COVID-19: Should I be tested? What you need to know about these precious tests


Governments around the world are fighting to contain and slow the rapid spread of the new coronavirus (137,445 infections and 5,088 deaths as of March 13). During this critical phase of the pandemic, social restrictions, confinement and screening tests are at the heart of the efforts.

Who should get tested?

Currently, there are two main cases for which a coronavirus screening test should be carried out: showing symptoms and / or having been in contact with an infected person.

The main symptoms of COVID-19, the disease caused by the coronavirus SARS-CoV-2, are: fever, dry cough and shortness of breath. These symptoms are very similar to those of the flu, so you need the advice of a doctor to determine if testing for the virus is necessary.

Local spread, sometimes without apparent signs…
Initially, the Centers for Disease Control and Prevention (CDC) recommended testing only people with symptoms who have been potentially exposed to the virus. However, to the surprise of public health officials, several of the first cases in the United States as well as in other countries, having tested positive for the virus, had no obvious exposure.

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This development therefore suggests that the virus is transmitted locally, which means that it spreads easily from one person to another and / or that individuals may have transmitted the virus without experiencing obvious symptoms.

In response, on March 4, 2020, the CDC changed their recommendations to allow anyone with symptoms similar to COVID-19 to be tested as long as a doctor approves the request. Since the number of tests available is limited, the CDC encourages physicians to minimize unnecessary tests and to consider the risks of exposure to a patient before ordering them.

Screening is important because it quarantines infected patients and stops the spread of the virus.

As of this writing, there is no specific drug, vaccine, or treatment available for COVID-19, but that does not mean that screening tests are unnecessary. On the contrary, it allows you to define which patients are actually infected so that they can be quarantined in order to limit the spread of the virus.

Another advantage of carrying out a test is that it allows public health professionals to get a better idea of ​​the number of cases and the spread of the virus in the local or national population.



What does the test look like?

For a patient, the virus screening process is simple and can potentially take place almost anywhere: it usually involves collecting a swab deep into the nasal cavity to collect cells from the back of the nose.

The sample is then sent to a laboratory where it will be tested to determine whether the patient's cells are infected with the virus or not. The same process is used to take a sample for the flu test.

How does the screening test work?

Although collecting a sample is easy, it is much more complicated to determine whether or not a person is infected with SARS-CoV-2. In fact, the current method consists in looking for the genetic material of the virus (ie RNA) in the cells of a patient.

In order to detect the presence of RNA, laboratories perform a procedure called reverse transcription polymerase chain reaction. This method consists first of converting any viral RNA into DNA, before replicating it millions of times until there are enough copies for detection to take place.

If virus genetic material is found in the sample, then it is confirmed that the patient is infected and has SARS-CoV-2. It usually takes between 24 and 72 hours to get the results of a test.

At the start of the ramp-up of testing, accuracy raised concerns after a study found that 3% of tests in China were negative while the samples were actually positive. But this type of genetic test is generally very accurate (more than rapid flu tests), and the health benefits of the test outweigh the risk of error.



Are there enough tests?

The availability of tests can indeed be a problem. You should know that the latter requires a kit: either specialized equipment and personnel trained accordingly.

Integrated DNA Technologies, a company collaborating with the CDC, shipped 700,000 tests to commercial, university and health laboratories on March 6 in the United States. Quest Diagnostics and LabCorp, two large commercial test manufacturers, have started manufacturing their own test kits, available since March 9.

Many companies, hospitals and other institutions are now fighting to develop more tests to diagnose COVID-19. On March 10, 2020, Alex Azar, Secretary of Health and Social Services, announced that 2.1 million test kits are now available, of which more than one million have been shipped to certified laboratories. Millions more are expected to ship this week.

Will all potential patients have to be tested?

Realistically, it is technically impossible to test all people potentially affected by COVID-19. Therefore, most health officials believe it is important to prioritize screening for those who need it most, those at high risk: those over the age of 65, immunocompromised, those with other diseases (heart disease, lung disease, diabetes), individuals who have been in close contact with infected patients as well as those showing symptoms and having traveled to areas with high rates of infection.

As more tests become available, more people will be able to be tested.

There is also a need to develop faster tests, which do not require special equipment and personnel. Namely, these tests allow experts to better understand the progression of the epidemic and try to predict the impact of the virus on society.

Much remains to be learned about this new coronavirus…

One day, this pandemic will end. However, in the meantime, the population must absolutely take care to respect the measures imposed, in particular the fact of washing their hands correctly and regularly, coughing in the crook of the elbow and trying to minimize the risk of exposure and / or transmission of the virus to other people by limiting social activities.




There is still a lot to learn about this new coronavirus, and only time will tell if it will disappear from the human population (as SARS did in 2004) or if it will become, like the flu, a seasonal disease.

Source

Friday, 13 March 2020

In obese people, bacteria escape from the intestine to spread throughout the body


Overweight and obesity are growing health issues across many developed and developing countries. Considered as a simple “handicap” in the eyes of some, in France, obesity is defined as being a real chronic disease. Recently, a team of researchers identified traces of bacterial DNA in the blood, liver and adipose tissue of obese people, revealing that fragments of bacteria (or whole living bacteria) infiltrate their bodies from the intestines.

Bacteria may be involved in the development of type 2 diabetes, according to a study published today in Nature Metabolism by researchers from Université Laval, the Québec Heart and Lung Institute (IUCPQ), and McMaster University.

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The authors found that the blood, liver, and certain abdominal fat deposits in diabetics have a different bacterial signature than in non-diabetics.

The researchers demonstrated this using blood and tissue samples from 40 patients suffering from severe obesity taken during bariatric surgery. Half of the participants suffered from type 2 diabetes, while the other subjects showed insulin resistance without being diabetic.

The researchers identified the bacterial genetic material in each of the tissues sampled, which came from the liver and three abdominal fat deposits. Based on the type of bacteria present and their relative abundance, the researchers were able to determine the bacterial signature for each tissue.



Their analysis revealed that the bacterial signature in diabetics was not the same as in non-diabetics. It also showed that the total number of bacteria varied from one tissue to another, and was highest in the liver and the greater omentum (a fatty tissue connecting the stomach and the transverse colon), two areas that play an important role in metabolic regulation.

“Our findings suggest that in people suffering from severe obesity, bacteria or fragments of bacteria are associated with the development of type 2 diabetes,” said the lead author, André Marette, professor at Université Laval’s Faculty of Medicine and researcher at the IUCPQ research centre.
According to the study, the bacterial genetic material detected in the tissues most likely comes from the intestine.

“We know that the intestinal barrier is more permeable in obese patients,” said Professor Marette. “Our hypothesis is that living bacteria and bacterial fragments cross this barrier and set off an inflammatory process that ultimately prevents insulin from doing its job, which is to regulate blood glucose levels by acting on metabolic tissues.”

Fernando Forato Anhê, an author on the paper and a postdoctoral research fellow at McMaster, added: “Location, location location...Beyond knowing the names of bacteria, their location is key to understanding how gut microbes influence host metabolism."

Professor Marette and his collaborators will be able to pursue their research further thanks to a $2 million grant they were recently awarded by the Canadian Institutes of Health Research.

“Our next objective is to determine if the bacteria found in the liver and fat deposits of people suffering from severe obesity are also present in those who are overweight or moderately obese,” said André Marette.



“We also want to see if certain pathogenic bacteria found in the tissues can trigger type 2 diabetes in an animal model. And lastly, we want to find out if certain beneficial bacteria found in these tissues can be used to prevent the development of the disease. If so, they might lead us to a new family of probiotic bacteria or a source of bacteria-based treatments to help fight diabetes,” concluded the researcher who is also a member of Université Laval’s Institute of Nutrition and Functional Foods (INAF).


Bibliography:

Type 2 diabetes influences bacterial tissue compartmentalisation in human obesity

Fernando F. Anhê, Benjamin Anderschou Holbech Jensen, Thibault V. Varin, Florence Servant, Sebastian Van Blerk, Denis Richard, Simon Marceau, Michael Surette, Laurent Biertho, Benjamin Lelouvier, Jonathan D. Schertzer, André Tchernof & André Marette.

Nat Metab (2020).

https://doi.org/10.1038/s42255-020-0178-9

ESO Telescope detected Exoplanet Where It Rains Iron


Commissioned in 1998 in the Atacama Desert in Chile, the VLT has made it possible to make numerous discoveries thanks to all of the scientific instruments that compose it. In particular, it has ESPRESSO, a spectrograph which makes it possible to search for planets similar to Earth, but whose capacities have in fact been revealed to be much broader. Indeed, thanks to him, a team of astrophysicists was able to study a giant ultra-hot exoplanet on which it literally rains liquid iron.

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Researchers using ESO's Very Large Telescope (VLT) have observed an extreme planet where they suspect it rains iron. The ultra-hot giant exoplanet has a day side where temperatures climb above 2400 degrees Celsius, high enough to vaporise metals. Strong winds carry iron vapour to the cooler night side where it condenses into iron droplets.

"One could say that this planet gets rainy in the evening, except it rains iron," says David Ehrenreich, a professor at the University of Geneva in Switzerland. He led a study, published today in the journal Nature, of this exotic exoplanet. Known as WASP-76b, it is located some 640 light-years away in the constellation of Pisces.



On day side and on night side with different atmospheric properties

This strange phenomenon happens because the 'iron rain' planet only ever shows one face, its day side, to its parent star, its cooler night side remaining in perpetual darkness. Like the Moon on its orbit around the Earth, WASP-76b is 'tidally locked': it takes as long to rotate around its axis as it does to go around the star.

Video showing the evolution of the WASP-76b exoplanet on its orbit:


On its day side, it receives thousands of times more radiation from its parent star than the Earth does from the Sun. It's so hot that molecules separate into atoms, and metals like iron evaporate into the atmosphere. The extreme temperature difference between the day and night sides results in vigorous winds that bring the iron vapour from the ultra-hot day side to the cooler night side, where temperatures decrease to around 1500 degrees Celsius.

Condensation and fallout of iron as precipitation

Not only does WASP-76b have different day-night temperatures, it also has distinct day-night chemistry, according to the new study. Using the new ESPRESSO instrument on ESO's VLT in the Chilean Atacama Desert, the astronomers identified for the first time chemical variations on an ultra-hot gas giant planet. They detected a strong signature of iron vapour at the evening border that separates the planet's day side from its night side. "Surprisingly, however, we do not see the iron vapour in the morning," says Ehrenreich. The reason, he says, is that "it is raining iron on the night side of this extreme exoplanet."

"The observations show that iron vapour is abundant in the atmosphere of the hot day side of WASP-76b," adds María Rosa Zapatero Osorio, an astrophysicist at the Centre for Astrobiology in Madrid, Spain, and the chair of the ESPRESSO science team. "A fraction of this iron is injected into the night side owing to the planet's rotation and atmospheric winds. There, the iron encounters much cooler environments, condenses and rains down."

This result was obtained from the very first science observations done with ESPRESSO, in September 2018, by the scientific consortium who built the instrument: a team from Portugal, Italy, Switzerland, Spain and ESO.

ESPRESSO -- the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations -- was originally designed to hunt for Earth-like planets around Sun-like stars. However, it has proven to be much more versatile. "We soon realised that the remarkable collecting power of the VLT and the extreme stability of ESPRESSO made it a prime machine to study exoplanet atmospheres," says Pedro Figueira, ESPRESSO instrument scientist at ESO in Chile.



"What we have now is a whole new way to trace the climate of the most extreme exoplanets," concludes Ehrenreich.


Bibliography:

Nightside condensation of iron in an ultrahot giant exoplanet.

Ehrenreich, D., Lovis, C., Allart, R. et al.

Nature, 2020;

DOI: 10.1038/s41586-020-2107-1

Wednesday, 11 March 2020

Air pollution will reduce life expectancy by 3 years on average for every person in the world


Among the many public health problems of global scope, pollution, although greatly underestimated, nevertheless rises to the top of the podium of the causes of mortality. Fine particles and other harmful aerosols cause long-term pulmonary and cardiovascular disease, which causes millions of deaths worldwide; far beyond other factors like HIV or smoking. Recently, a team of researchers has shown that on average, around the world, air pollution reduces life expectancy per capita by around 3 years.

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Polluted air is a public health hazard that cannot be evaded. It is widely known that long-term exposure to air pollution enhances the risks of cardiovascular and respiratory diseases.

Scientists from the Max Planck Institute for Chemistry and the University Medical Center Mainz now calculated in a new study that the global, public loss of life expectancy caused by air pollution is higher than many other risk factors such as smoking, infectious diseases or violence.



Pollution: it reduces life expectancy per capita by around 3 years on average worldwide

Air pollution caused 8.8 million premature deaths worldwide in 2015. This corresponds to an average reduction in life expectancy per capita of 2.9 years. In comparison, tobacco smoking reduces the life expectancy by an average of 2.2 years (7.2 million deaths), HIV / AIDS by 0.7 years (1 million deaths), parasitic and vector-borne diseases such as malaria -- by 0.6 years (600,000 deaths).

"Air pollution exceeds malaria as a cause of premature death by a factor of 19; it exceeds violence by a factor of 17 and HIV / AIDS by a factor of 9. Given the huge impact on public health and the global population, one could say that our results indicate an air pollution pandemic," said Jos Lelieveld, director at Max Planck Institute for Chemistry and first author of the study.

Loss of average life expectancy according to different causes of death for the year 2015. Air pollution reaches the top of the podium with approximately 3 years of life expectancy lost. Credits: Jos Lelieveld et al. 2020

This study is the first to examine the global impact of air pollution on human health compared to other risk factors worldwide. "Our comparison of different global risk factors shows that ambient air pollution is a leading cause of premature mortality and loss of life expectancy, in particular through cardiovascular diseases," says Thomas Münzel, director of the Cardiology Center at the University Medical Center in Mainz and co-author of the paper.

The links between pollution and "pulmonary and cardiovascular" diseases

The scientists examined the connection between exposure to pollutants and the occurrence of diseases. In order to calculate the worldwide exposure to pollutants, which primarily include fine particles and ozone, the researchers used an atmospheric chemical mode. They then combined the exposure data with the Global Exposure -- Mortality Model that derives from many epidemiological cohort studies.

Using these tools and data, scientists investigated the effects of different pollution sources, distinguishing between natural (wildfires, aeolian dust) and anthropogenic emissions, including fossil fuel use. Based on their results they could estimate the disease-specific excess mortality and loss of life expectancy in all countries world-wide.

Percentage loss of life expectancy due to air pollution by different types of diseases: CEV = cerebrovascular disease, COPD = chronic obstructive pulmonary disease, IHD = ischemic heart disease, LC = lung cancer, LRI: infection lower respiratory tract, NCD = other diseases. Credits: Jos Lelieveld et al. 2020

The study results show that the mortality caused by ambient air pollution is highest in East Asia (35 percent) and South Asia (32 percent), followed by Africa (11 percent), Europe (9 percent) and North- and South America (6 percent). Lowest mortality rates are found in Australia (1,5 percent) associated with the strictest air quality standards of all countries.

"We understand more and more that fine particles primarily favor vascular damage and thus diseases such as heart attack, stroke, cardiac arrhythmia and heart failure. It is of outmost importance that air pollution is adopted as a cardiovascular risk factor and that it is distinctly mentioned in the ESC/AHA guidelines of prevention, acute and coronary syndromes and heart failure," continued Münzel.

Reducing the use of fossil fuels to reduce pollution-related deaths

According to the findings of the study, almost two thirds of the deaths caused by air pollution, namely around 5.5 million a year are avoidable, and the majority of polluted air comes from the use of fossil fuels. The researchers estimate that the average life expectancy world-wide would increase by more than a year if the emissions from the use of fossil fuels were eliminated.



The team from the University Medical Center Mainz and Max Planck Institute for Chemistry published a similar paper last year focusing on the consequences of air pollution in Europe. According to the earlier study, nearly 800,000 Europeans die prematurely every year due to illnesses caused by air pollution. Polluted air shortens the lifespan of Europeans by more than two years.


Bibliography:

Loss of life expectancy from air pollution compared to other risk factors: a worldwide perspective.

Thomas Münzel, Andy Haines, Mohammed Fnais, Ulrich Pöschl, Andrea Pozzer, Jos Lelieveld.

Cardiovascular Research, 2020;

DOI: 10.1093/cvr/cvaa025

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