Scientists build whole functioning thymus from human cells

Researchers at the Francis Crick Institute and University College London have rebuilt a human thymus, an essential organ in the immune system, using human stem cells and a bioengineered scaffold. Their work is an important step towards being able to build artificial thymi which could be used as transplants.

The thymus is an organ in the chest where T lymphocytes, which play a vital role in the immune system, mature. If the thymus does not work properly or does not form during foetal development in the womb, this can lead to diseases such as severe immunodeficiency, where the body cannot fight infectious diseases or cancerous cells, or autoimmunity, where the immune system mistakenly attacks the patient's own healthy tissue.

In their proof-of-concept study, published in Nature Communications today, the scientists rebuilt thymi using stem cells taken from patients who had to have the organ removed during surgery. When transplanted into mice, the bioengineered thymi were able to support the development of mature and functional human T lymphocytes.

While researchers have previously rebuilt other organs or sections of organs, this is the first-time scientists have successfully rebuilt a whole working human thymus. 

Campinoti, S et al. (2020). Reconstitution of a functional human thymus by postnatal stromal progenitor cells and natural whole-organ scaffolds. Nature Communications, DOI: 10.1038/s41467-020-20082-7

https://medicalxpress.com/news/2020-12-scientists-functioning-thymu...

Some droughts during the Indian monsoon are due to unique North Atl...

A team of researchers from the Indian Institute of Science and Cotton University has found that some droughts during monsoon season in India are due to unique North Atlantic disturbances. In their paper published in the journal Science, the group describes their study of weather patterns in South Asia over the past century and what it showed about monsoon season droughts.

P. J. Borah et al. Indian monsoon derailed by a North Atlantic wavetrain, Science (2020). DOI: 10.1126/science.aay6043

--

Current pace of action on climate change is "unthinkable" state ex ...

Justifiable pride can be taken in the incremental accomplishments of international climate change cooperation, but it is "unthinkable" to continue at the current pace. The global response to climate change is completely insufficient and leaves the world on a "road to hell".

Climate Policy (2020). DOI: 10.1080/14693062.2020.1860567

**

Black holes gain new powers when they spin fast enough

General relativity is a profoundly complex mathematical theory, but its description of black holes is amazingly simple. A stable black hole can be described by just three properties: its mass, its electric charge and its rotation or spin. Since black holes aren't likely to have much charge, it really takes just two properties. If you know a black hole's mass and spin, you know all there is to know about the black hole.

This property is often summarized as the no-hair theorem. Specifically, the theorem asserts that once matter falls into a black hole, the only characteristic that remains is mass. You could make a black hole out of a sun's worth of hydrogen, chairs or those old copies of National Geographic from Grandma's attic, and there would be no difference. Mass is mass as far as general relativity is concerned. In every case, the event horizon of a black hole is perfectly smooth, with no extra features. "The balck holes have no hair."

But with all its predictive power, general relativity has a problem with quantum theory. This is particularly true with black holes. If the no-hair theorem is correct, the information within an object is destroyed when it crosses the event horizon. Quantum theory says that information can never be destroyed. So the valid theory of gravity is contradicted by the valid theory of the quanta. This leads to problems such as the firewall paradox, which can't decide whether an event horizon should be hot or cold.

Several theories have been proposed to solve this contradiction, often involving extensions to relativity. The difference between standard relativity and these modified theories can only be seen in extreme situations, making them difficult to study observationally. But a new paper in Physical Review Letters shows how they might be studied through the spin of a black hole.

Many modified relativity theories have an extra parameter not seen in the standard theory. Known as a massless scalar field, it allows Einstein's model to connect with quantum theory  in a way that isn't contradictory. In this new work, the team looked at how such a scalar field connects to the rotation of a black hole. They found that at low spins, a modified black hole is indistinguishable from the standard model, but at high rotations, the scalar field allows a black hole to have extra features. In other words, in these alternative models, rapidly rotating black holes can have hair.

The hairy aspects of rotating black holes would only be seen near the event horizon itself, but they would also affect merging black holes. As the authors point out, future gravitational wave observatories should be able to use rapidly rotating black holes to determine whether an alternative to general relativity is valid.

Einstein's theory of general relativity has passed every observational challenge so far, but it will likely break down in the most extreme environments of the universe. Studies such as this show how we might be able to discover the theory that comes next.

 Alexandru Dima et al. Spin-Induced Black Hole Spontaneous Scalarization, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.231101

https://phys.org/news/2020-12-black-holes-gain-powers-fast.html?utm...

How epigenetic switches control gene expression

Scientists at Tokyo Institute of Technology have deciphered how to quantitatively assess the effects of specific epigenetic changes on the rate of transcription by developing a mathematical model. Using their method, they successfully generated reconstituted chromatin-bearing histone modifications in vitro. Their study published in Nucleic Acids Research provides an accurate quantitative approach for understanding how site-specific changes to histone proteins impact the accessibility of chromatin and gene expression levels.

Masatoshi Wakamori et al, Quantification of the effect of site-specific histone acetylation on chromatin transcription rate, Nucleic Acids Research (2020). DOI: 10.1093/nar/gkaa1050

https://phys.org/news/2020-12-epigenetic-gene.html?utm_source=nwlet...

Researchers find why 'lab-made' proteins have unusually high temperature stability

Bioengineers have found why proteins that are designed from scratch tend to be more tolerant to high temperatures than proteins found in nature.

Rie Koga et al, Robust folding of a de novo designed ideal protein even with most of the core mutated to valine, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2002120117

https://phys.org/news/2020-12-lab-made-proteins-unusually-high-temp...

Study sheds light on diabetes and COVID interaction
NASHVILLE, TN.- COVID-19 has been linked to cases of new-onset diabetes, diabetes-related emergencies and a higher death rate among diabetes patients. While this suggests that SARS-CoV-2, the virus that causes COVID-19, may infect and damage the insulin-producing beta cells of the pancreas, that does not appear to be the case, according to a report by researchers at Vanderbilt University Medical Center published Dec. 1 in the journal Cell Metabolism. “This is important information in terms of understanding the interaction of diabetes and SARS-CoV-2 and COVID-19,” said Katie Coate, PhD, who led the study with Jeeyeon Cha, MD, PhD. “There are other potential pathways for how SARS-CoV-2 infects cells, and these are just beginning to be described or are as yet undiscovered

Charles Darwin was right about why insects are losing the ability to fly

Most insects can fly.

Yet scores of species have lost that extraordinary ability, particularly on islands.

On the small islands that lie halfway between Antarctica and continents like Australia, almost all the insects have done so.

Flies walk, moths crawl.

Of course, Charles Darwin knew about this wing loss habit of island insects. He and the famous botanist Joseph Hooker had a substantial argument about why this happens. Darwin's position was deceptively simple. If you fly, you get blown out to sea. Those left on land to produce the next generation are those most reluctant to fly, and eventually evolution does the rest. 

But since Hooker expressed his doubt, many other scientists have too.

In short, they have simply said Darwin got it wrong.

Yet almost all of these discussions have ignored the place that is the epitome of flight loss—those 'sub-Antarctic' islands. Lying in the 'roaring forties' and 'furious fifties', they're some of the windiest places on Earth.

If Darwin really got it wrong, then wind would not in any way explain why so many insects have lost their ability to fly on these islands.

Using a large, new dataset on insects from sub-Antarctic and Arctic islands, Monash University researchers examined every idea proposed to account for flight loss in insects, including Darwin's wind idea.

Reporting today in Proceedings of the Royal Society B, they show that Darwin was right for this 'most windy of places'. None of the usual ideas (such as those proposed by Hooker) explain the extent of flight loss in sub-Antarctic insects, but Darwin's idea does. Although in a slightly varied form, in keeping with modern ideas on how flight loss actually evolves.

Windy conditions make insect flight more difficult and energetically costly. Thus, insects stop investing in flight and its expensive underlying machinery (wings, wing muscles) and redirect the resources to reproduction.

Wind plays a major but not exclusive role in the prevalence of insect flight loss on remote islands.

 Proceedings of the Royal Society B, rspb.royalsocietypublishing.or … .1098/rspb.2020.2121

https://phys.org/news/2020-12-charles-darwin-insects-ability.html?u...

Expandable Foam Supersizes 3D-Printed Objects - Headline Science

Physicists create time-reversed optical waves

Optics researchers  have developed a new technique to demonstrate the time reversal of optical waves, which could transform the fields of advanced biomedical imaging and telecommunications.

Time reversal of waves in physics doesn't mean traveling back to the future; it describes a special type of wave which can retrace a path backwards through an object, as if watching a movie of the traveling wave, played in reverse.

UQ's Dr. Mickael Mounaix and Dr. Joel Carpenter, together with Dr. Nick Fontaine's team at Nokia Bell Labs, are the first to demonstrate this time reversal of optical waves, using a new device they developed that allows full 3-D control of light through an optical fiber.

Time reversed optical waves by arbitrary vector spatiotemporal field generation 

https://phys.org/news/2020-12-physicists-time-reversed-optical.html...

** Toward imperceptible electronics that you cannot see or feel

Transparent electronics—such as head-up displays that allow pilots to read flight data while keeping their eyes ahead of them—improve safety and allow users to access data while in transit. For healthcare applications, the electronics need to not only be cheap and straightforward to fabricate, but also sufficiently flexible to conform to skin. Silver nanowire networks meet these criteria. However, current methods of development create random nanowire alignment that's insufficient for advanced applications.

--

Nanoparticles, from hype to actual clinical product

Ph.D. candidate Jaleesa Bresseleers, of the TU/e department of Biomedical Engineering, investigated a robust and scalable manufacturing process for nanocarriers and their building blocks. With these insights, the road to widely available clinical applications for nanocarriers has become much shorter.

--

The moon controls the release of methane in Arctic Ocean

It may not be very well known, but the Arctic Ocean leaks enormous amounts of the potent greenhouse gas methane. These leaks have been ongoing for thousands of years but could be intensified by a future warmer ocean. The potential for this gas to escape the ocean, and contribute to the greenhouse gas budget in the atmosphere, is an important mystery that scientists are trying to solve.

--

A young but completely evolved entirely self-made galaxy

So young and already so evolved: Thanks to observations obtained at the Large Binocular Telescope, an international team of researchers coordinated by Paolo Saracco of the Istituto Nazionale di Astrofisica (INAF, Italy) was able to reconstruct the wild evolutionary history of an extremely massive galaxy that existed 12 billion years ago, when the universe was only 1.8 billion years old, less than 13% of its present age. This galaxy, dubbed C1-23152, formed in only 500 million years, an incredibly short time to give rise to a mass of about 200 billion suns. To do so, it produced as many as 450 stars per year, more than one per day, a star formation rate almost 300 times higher than the current rate in the Milky Way. The information obtained from this study will be fundamental for galaxy formation models for objects it for which it is currently difficult to account.

**The moon controls the release of methane in Arctic Ocean

It may not be very well known, but the Arctic Ocean leaks enormous amounts of the potent greenhouse gas methane. These leaks have been ongoing for thousands of years but could be intensified by a future warmer ocean. The potential for this gas to escape the ocean, and contribute to the greenhouse gas budget in the atmosphere, is an important mystery that scientists are trying to solve.

The total amount of methane in the atmosphere has increased immensely over the past decades, and while some of the increase can be ascribed to human activity, other sources are not very well constrained.

A recent paper in Nature Communications even implies that the moon has a role to play.

The moon controls one of the most formidable forces in nature—the tides that shape our coastlines. Tides, in turn, significantly affect the intensity of methane emissions from the Arctic Ocean seafloor.

Researchers noticed that gas accumulations, which are in the sediments within a meter from the seafloor, are vulnerable to even slight pressure changes in the water column. Low tide means less of such hydrostatic pressure and higher intensity of methane release. High tide equals high pressure and lower intensity of the release.

It is the first time that this observation has been made in the Arctic Ocean. It means that slight pressure changes can release significant amounts of methane. This is a game-changer and the highest impact of the study.

Nabil Sultan et al, Impact of tides and sea-level on deep-sea Arctic methane emissions, Nature Communications (2020). DOI: 10.1038/s41467-020-18899-3

https://phys.org/news/2020-12-moon-methane-arctic-ocean.html?utm_so...

Chance played a major role in keeping Earth fit for life

A study by the University of Southampton gives a new perspective on why our planet has managed to stay habitable for billions of years—concluding it is almost certainly due, at least in part, to chance. The research suggests this may shorten the odds of finding life on so-called 'twin-Earths' in the Universe.

** 

Hibernating lemurs may be the key to cryogenic sleep for human spac...

Science fiction is shifting into reality. With humanity's plans to return to the moon this decade and further ambitions to travel to Mars in the next, we need to figure out how to keep astronauts healthy for these years-long missions. One solution long championed by science fiction is suspended animation, or putting humans in a hibernation-like sleep for the duration of travel time.

--

AI can predict Twitter users likely to spread disinformation before...

A new artificial intelligence-based algorithm that can accurately predict which Twitter users will spread disinformation before they actually do it has been developed by researchers from the University of Sheffield.

Improving portraits by adding light after a picture was taken

Recently, Google introduced Portrait Light, a feature on its Pixel phones that can be used to enhance portraits by adding an external light source not present at the time the photo was taken. In a new blog post, Google explains how they made this possible.

In their post, engineers at Google Research note that professional photographers discovered long ago that the best way to make people look their best in portraits is by using secondary flash devices that are not attached to the camera. Such flash devices can be situated by the photographer prior to photographing a subject by taking into account the direction their face is pointing, other light available, skin tone and other factors. Google has attempted to capture those factors with its new portrait-enhancing software. The system does not require the camera phone operator to use another light source. Instead, the software simply pretends that there was another light source all along, and then allows the user to determine the most flattering configuration for the subject.

The engineers explain they achieved this feat using two algorithms. The first, which they call automatic directional light placement, places synthetic light into the scene as a professional photographer would. The second algorithm is called synthetic post-capture relighting. It allows for repositioning the light after the fact in a realistic and natural-looking way.

Both of the algorithms rely on deep-learning networks. Google trained the software using available photographs and by photographing hundreds of portrait shots of 70 people with lights placed in 331 locations and cameras placed at 64 viewpoints. They also employed well-known principles such as the best angles for placing lights relative to the particular features of a person's face.

The software is available in newer Pixel phones. Older camera users can try the new software on the Google Photos online service, while it's built into newer phones. Users can either accept the automatic enhancement provided by their phone or change it manually.

https://ai.googleblog.com/2020/12/portrait-light-enhancing-portrait...

https://techxplore.com/news/2020-12-portraits-adding-picture.html?u...

A Deep Dive On Deepfakes Telling fact from fiction may be harder than you think—a new study from Singapore has found that even people aware of deepfakes have inadvertently shared them online. 

Ahmed (2020) Who Inadvertently Shares Deepfakes? Analyzing the Role of Political Interest, Cognitive Ability, and Social Network Size. https://www.asianscientist.com/2020/12/tech/deepfakes-social-media-...

Spiders in Space

Sleep, Memory and Dreams: Fitting the Pieces Together

https://www.the-scientist.com/videos/whats-in-a-dream-68223?utm_cam...

The bats that wear face masks!

The wrinkle-faced bat covers its face with a flap of skin, seemingly as part of its courtship rituals.

https://www.scientificamerican.com/podcast/episode/this-bat-wears-a...

Embryonic development in a Petri dish

 It would certainly spare mothers the hardships of pregnancy, but mammals do not grow in eggs. In a way, this is also impractical for science. While embryos of fish, amphibians or birds can be easily watched growing, mammalian development evades the gaze of the observer as soon as the embryo implants into the uterus. This is precisely the time when the embryo undergoes profound changes in shape and develops precursors of various organs  a highly complex process that leaves many questions unanswered. But now a research team  succeeded in replicating a central phase of embryonic development in a cell culture approach by growing the core portion of the trunk from mouse embryonic stem cells for the first time. The method recapitulates the early shape-generating processes of embryonic development in the Petri dish. 

A gel provides support and spatial orientation
So far, it has only been possible to grow cell clusters from embryonic stem cells, so-called gastruloids. “Cellular assemblies in gastruloids develop to a similar extent like in our trunk-like structures, but they do not assume the typical appearance of an embryo” says Jesse Veenvliet, one of the two lead authors of the study. “The cell clusters lack the signals that trigger their organization into a meaningful arrangement.”

In the cell culture, the required signal is generated by a special gel that mimics the properties of the extracellular matrix. This jelly-like substance consists of a complex mixture of extended protein molecules that is secreted by cells and is found throughout the body as an elastic filling material, especially in connective tissues. The utilization of this gel is the crucial “trick” of the new method.
Cells with similar properties as in the embryo
After four to five-days, the team dissolved the structures into single cells and analyzed them individually. “Even though not all cell types are present in the trunk-like structures, they are strikingly similar to an embryo of the same age.

https://researchnews.cc/news/4117/Embryonic-development-in-a-Petri-...

**

Chameleon-like material spiked with boron comes closer to mimicking brain cells

** 

Apathy could predict onset of dementia years before other symptoms

Apathy—a lack of interest or motivation—could predict the onset of some forms of dementia many years before symptoms start, offering a 'window of opportunity' to treat the disease at an early stage, according to new research from a team of scientists.

Frontotemporal dementia is a significant cause of dementia among younger people. It is often diagnosed between the ages of 45 and 65. It changes behaviour, language and personality, leading to impulsivity, socially inappropriate behaviour, and repetitive or compulsive behaviours.

A common feature of frontotemporal dementia is apathy, with a loss of motivation, initiative and interest in things. It is not depression, or laziness, but it can be mistaken for them. Brain scanning studies have shown that in people with frontotemporal dementia it is caused by shrinkage in special parts at the front of the brain—and the more severe the shrinkage, the worse the apathy. But, apathy can begin decades before other symptoms, and be a sign of problems to come.

Malpetti, M et al. Apathy in pre-symptomatic genetic frontotemporal dementia predicts cognitive decline and is driven by structural brain changes. Alzheimer's & Dementia; 14 Dec 2020; DOI: 10.1002/alz.12252

https://medicalxpress.com/news/2020-12-apathy-onset-dementia-years-...

Reducing pesticide use with nanoparticles

Researchers  have discovered how certain silica nanoparticles could act as a traceless, degradable, and highly efficient treatment against some plant pathogens.

 With an increasing number of products banned or considered dangerous for human and animal health, the need for substitutes is acute. One approach is to stimulate plants' own immune response to pathogen attacks. Silicic acid, which naturally occurs in soil, is known to provoke such responses in plants, and amorphous silica nano-particles can release this substance in small amounts. These nanoparticles, which are also naturally present in many food crops such as cereals, are more common than most people think. They are part of food grade silica (SiO2), otherwise known as E551 on labels and packaging, and used for decades in a variety of products such as table salt, pills, or protein powders to avoid clumping.

With this in mind, the researchers aimed to create an environmentally safe nano-agrochemical for the targeted delivery of silicic acid and to stimulate plant defense. They synthesized silica nanoparticles with similar properties to those found in plants. To test their efficiency, they applied the nanoparticles on Arabidopsis thaliana (thale cress), a widely used plant model, infected with the bacterial pest Pseudomonas syringae, another model organism. The results showed that their nanoparticles can boost resistance against the bacteria in a dose-dependent manner by stimulating the plant's defense hormone, salicylic acid (which is also the active ingredient in aspirin). The researchers also investigated the interactions of the nanoparticles with plant leaves. They were able to show that nanoparticle uptake and action occurred exclusively through the leaf pores (stomata) that allow the plants to breathe.

Mohamed El-Shetehy et al. Silica nanoparticles enhance disease resistance in Arabidopsis plants, Nature Nanotechnology (2020). DOI: 10.1038/s41565-020-00812-0

https://phys.org/news/2020-12-pesticide-nanoparticles.html?utm_sour...

Shedding light on the dark side of biomass burning pollution

Oxidized organic aerosol is a major component of ambient particulate matter, substantially impacting climate, human health and ecosystems. Oxidized aerosol from biomass burning is especially toxic, known to contain a large amount of mutagens that are known carcinogens. Inhaling biomass burning particles can also cause oxidative stress and a wide range of diseases such as heart attacks, strokes and asthma. Oxidized aerosol primarily forms from the atmospheric oxidation of volatile and semi-volatile compounds emitted by sources like biomass burning, resulting in products that readily form particulate matter. Every model in use today assumes that oxidized aerosol forms in the presence of sunlight, and that it requires days of atmospheric processing to reach the levels observed in the environment. Naturally, this implies that oxidized aerosol forms in the daytime and mostly during periods with plentiful sunshine, such as in summer.

However, considerable amounts of oxidized organic aerosol forms during the winter and in other periods of low photochemical activity worldwide, often during periods of intense biomass burning. Models underestimate oxidized aerosol levels by a factor of three to five. This unresolved mystery carries significant implications for public health and climate, given that biomass burning events are often associated with population exposure to very high particulate matter levels. This issue will become more important in the future, given the increase intensity, duration and frequency of wood burning (both domestic and wildfire) around the globe.

John K. Kodros el al., "Rapid dark aging of biomass burning as an overlooked source of oxidized organic aerosol," PNAS (2020). www.pnas.org/cgi/doi/10.1073/pnas.2010365117

https://phys.org/news/2020-12-dark-side-biomass-pollution.html?utm_...

Giant Viruses Can Integrate into the Genomes of Their Hosts

Rather than introducing small chunks of DNA as other viruses do, some giant viruses can contribute more than 1 million base pairs to a host’s genome, broadening the ways in which viruses may shape eukaryote evolution.

https://www.nature.com/articles/s41586-020-2924-2.epdf?sharing_toke...

https://www.the-scientist.com/news-opinion/giant-viruses-can-integr...

Quantum insulators create multilane highways for electrons

New energy-efficient electronic devices may be possible thanks to research that demonstrates the quantum anomalous Hall (QAH) effect—where an electrical current does not lose energy as it flows along the edges of the material—over a broader range of conditions. A team of researchers from Penn State has experimentally realized the QAH effect in a multilayered insulator, essentially producing a multilane highway for the transport of electrons that could increase the speed and efficiency of information transfer without energy loss.

Tuning the Chern number in quantum anomalous Hall insulators, Nature (2020). DOI: 10.1038/s41586-020-3020-3 , www.nature.com/articles/s41586-020-3020-3

https://phys.org/news/2020-12-quantum-insulators-multilane-highways...

New type of atomic clock could help scientists detect dark matter and study gravity's effect on time

Atomic clocks are the most precise timekeepers in the world. These exquisite instruments use lasers to measure the vibrations of atoms, which oscillate at a constant frequency, like many microscopic pendulums swinging in sync. The best atomic clocks in the world keep time with such precision that, if they had been running since the beginning of the universe, they would only be off by about half a second today.

Still, they could be even more precise. If atomic clocks could more accurately measure atomic vibrations, they would be sensitive enough to detect phenomena such as dark matter and gravitational waves. With better atomic clocks, scientists could also start to answer some mind-bending questions, such as what effect gravity might have on the passage of time and whether time itself changes as the universe ages.

Now a new kind of atomic clock designed by MIT physicists may enable scientists explore such questions and possibly reveal new physics.

The researchers report in the journal Nature that they have built an atomic clock that measures not a cloud of randomly oscillating atoms, as state-of-the-art designs measure now, but instead atoms that have been quantumly entangled. The atoms are correlated in a way that is impossible according to the laws of classical physics, and that allows the scientists to measure the atoms' vibrations more accurately.

The new setup can achieve the same precision four times faster than clocks without entanglement.

Entanglement on an optical atomic-clock transition, Nature (2020). DOI: 10.1038/s41586-020-3006-1 , www.nature.com/articles/s41586-020-3006-1

https://phys.org/news/2020-12-atomic-clock-precisely.html?utm_sourc...

Where does the Earth's heat come from?

Earth generates heat. The deeper you go, the higher the temperature. At 25km down, temperatures rise as high as 750°C; at the core, it is said to be 4,000°C. Humans have been making use of hot springs as far back as antiquity, and today we use geothermal technology to heat our apartments. Volcanic eruptions, geysers and earthquakes are all signs of the Earth's internal powerhouse.

The average heat flow from the earth's surface is 87mW/m² – that is, 1/10,000th of the energy received from the sun, meaning the earth emits a total of 47 terawatts, the equivalent of several thousand nuclear power plants. The source of the earth's heat has long remained a mystery, but we now know that most of it is the result of radioactivity.

The birth of atoms

To understand where all this heat is coming from, we have to go back to the birth of the atomic elements.

The Big Bang produced matter in the form of protons, neutrons, electrons, and neutrinos. It took around 370,000 years for the first atoms to form—protons attracted electrons, producing hydrogen. Other, heavier nuclei, like deuterium and helium, formed at the same time, in a process called Big Bang nucleosynthesis.

The creation of heavy elements was far more arduous. First, stars were born and heavy nuclei formed via accretion in their fiery crucible. This process, called stellar nucleosynthesis, took billions of years. Then, when the stars died, these elements spread out across space to be captured in the form of planets.

The earth's composition is therefore highly complex. Luckily for us, and our existence, it includes all the natural elements, from the simplest atom, hydrogen, to heavy atoms such as uranium, and everything in between, carbon, iron—the entire periodic table. Inside the bowels of the earth is an entire panoply of elements, arranged within various onion-like layers.

We know little about the inside of our planet. The deepest mines reach down 10km at the most, while the earth has a radius of 6,500km. Scientific knowledge of deeper levels has been obtained through seismic measurements. Using this data, geologist divided the earth's structure into various strata, with the core at the center, solid on the inside and liquid on the outside, followed by the lower and upper mantles and, finally, the crust. The earth is made up of heavy, unstable elements and is therefore radioactive, meaning there is another way to find out about its depths and understand the source of its heat.

Radioactivity is a common and inescapable natural phenomenon. Everything on earth is radioactive—that is to say, everything spontaneously produces elementary aprticles (humans emit a few thousand per second).

There are various kinds of radioactivity, each involving the spontaneous release of particles and emitting energy that can be detected in the form of heat deposits. Here, we will be talking about "beta" decay, where an election and a neutrino are emitted. The electron is absorbed as soon as it is produced, but the neutrino has the surprising ability to penetrate a wide range of materials. The whole of the Earth is transparent to neutrinos, so detecting neutrinos generated by radioactive decay within the Earth should give us an idea of what is happening at its deepest levels.

These kinds of particles are called geonutrinos, and they provide an original way to investigate the depths of the Earth. Although detecting them is no easy matter, since neutrinos interact little with matter, some detectors are substantial enough to perform this kind of research.

https://theconversation.com/where-does-the-earths-heat-come-from-15...

A pair of lonely planet-like objects born like stars

A pair of lonely planet-like objects born like stars

An international research team led by the University of Bern has discovered an exotic binary system composed of two young planet-like objects, orbiting around each other from a very large distance. Although these objects look like giant exoplanets, they formed in the same way as stars, proving that the mechanisms driving star formation can produce rogue worlds in unusual systems deprived of a Sun.

Star-forming processes sometimes create mysterious astronomical objects called brown dwarfs, which are smaller and colder than stars, and can have masses and temperatures down to those of exoplanets in the most extreme cases. Just like stars, brown dwarfs often wander alone through space, but can also be seen in binary systems, where two brown dwarfs orbit one another and travel together in the galaxy.

Clémence Fontanive et al. A wide planetary-mass companion to a young low-mass brown dwarf in Ophiuchus, arxiv.org/abs/2011.08871 accepted for publication in The Astrophysical Journal Letters, DOI: 10.3847/2041-8213/abcaf8

https://phys.org/news/2020-12-pair-lonely-planet-like-born-stars.ht...

Scientists set a path for field trials of gene drive organisms

The modern rise of gene drive research, accelerated by CRISPR-Cas9 gene editing technology, has led to transformational waves rippling across science.

Gene drive organisms (GDOs), developed with select traits that are genetically engineered to spread through a population, have the power to dramatically alter the way society develops solutions to a range of daunting health and environmental challenges, from controlling dengue fever and malaria to protecting crops against plant pests.

But before these gene drive organisms move from the laboratory to testing in the field, scientists are proposing a course for responsible testing of this powerful technology. These issues are addressed in a new Policy Forum article on biotechnology governance, "Core commitments for field trials of gene drive organisms," published Dec. 18, 2020 in Science by more than 40 researchers.

The new commitments that address field trials are to ensure that the trials are safely implemented, transparent, publicly accountable and scientifically, politically and socially robust.

A multidisciplinary group of gene drive organism developers, ecologists and con¬servation biologists joined experts in social science, ethics and policy to outline several commitments that they deem "critical for responsible conduct of a field trial and to ensure that these technologies, if they are introduced, serve the public interest." Twelve core commitments were developed under the following broad categories: fair partnership and transparency; product efficacy and safety; regulatory evaluation and risk/benefit assessment; and monitoring and mitigation.

K.C. Long el al., "Core commitments for field trials of gene drive," Science (2020). science.sciencemag.org/cgi/doi … 1126/science.abd1908

--

 "gene drive" has been used both to describe a process (the biological activity of gene drive spreading in a population) and to describe an object (the development of a "gene drive" engineering tool).

https://phys.org/news/2020-12-scientists-path-field-trials-gene.htm...

Popular European football games linked to traffic accidents in Asia

Days when high profile European football matches are played are associated with more traffic accidents in Asia than days when less popular matches are played, finds a study in the Christmas issue of The BMJ.

One explanation may be that Asian drivers stay awake until the early hours of the morning to watch high profile football games and lose sleep as a result.

Football is viewed by more people worldwide than any other sport, but most high profile games are played in Europe, so fans who live outside Europe must watch these games at odd local times owing to differences in time zones.

Asian fans are the most affected, as games scheduled to start at 8 pm in Europe means fans in Beijing, Hong Kong, and Singapore have to stay up until 4 30 am to finish the game, while fans in Seoul and Tokyo have to stay up until 5 30 am.

Given that sleep deprivation is associated with poor attention management, slower reaction times, and impaired decision making, one theory is that drivers are more likely to be involved in traffic accidents on days when high profile football games air early in the morning.

If true, this would have important policy implications, as traffic accidents can result in considerable economic and medical costs.

After taking account of potentially influential factors such as driver age, gender and experience, weather conditions, time of year, and weekend versus weekday effects, the researchers found that days when high profile football games were aired also had higher than average traffic accidents in both Singapore and Taiwan.

Association of high profile football matches in Europe with traffic accidents in Asia: archival study, BMJ (2020). DOI: 10.1136/bmj.m4465

https://medicalxpress.com/news/2020-12-popular-european-football-ga...

--

Based on these figures, the researchers estimate that football games may be responsible for at least 371 accidents a year among taxi drivers in Singapore (this figure is likely to be much larger across all drivers in Singapore) and around 41,000 accidents per year among the Taiwanese general public.

In terms of annual economic losses, they estimate these to be more than €820,000 among Singapore taxi drivers and almost €14m among Taiwanese drivers and insurance companies, although they stress that these figures should be interpreted with caution.

This is an observational study, so can't establish cause, although the researchers were able to rule out many alternative explanations such as roadside conditions and driver characteristics. The researchers also point to some limitations, such as a lack of data on the severity of the accidents reported and being unable to compare match days against non-game days.

Nevertheless, they suggest that football's governing bodies could consider scheduling high profile games on Friday or Saturday evenings local European time (Saturday or Sunday early mornings local Asian time) when fans can sleep in immediately after watching games.

The most consumed species of mussels contain microplastics all arou...

"If you eat mussels, you eat microplastics." 

A research team investigated the microplastic load of four mussel species which are particularly often sold as food in supermarkets from twelve countries around the world. The scientists now present their research results in the journal Environmental Pollution.

All the samples analyzed contained microplastic particles, and the researchers detected a total of nine different types of plastic. Polypropylene (PP) and polyethylene terephthalate (PET) were the most common types of plastic. Both are plastics ubiquitous to people's everyday lives all over the world. To make the analyses of different sized mussels comparable, one gram of mussel meat was used as a fixed reference. According to the study, one gram of mussel meat contained between 0.13 and 2.45 microplastic particles. Mussel samples from the North Atlantic and South Pacific were the most contaminated. Because mussels filter out microplastic particles from the water in addition to food particles, a microplastic investigation of the mussels allows indirect conclusions to be drawn about pollution in their respective areas of origin.

The microplastic particles detected in the mussels were of a size of between three and 5,000 micrometers, i.e. between 0.003 and five millimeters.

B.N. Vinay Kumar et al. Analysis of microplastics of a broad size range in commercially important mussels by combining FTIR and Raman spectroscopy approaches, Environmental Pollution (2020). DOI: 10.1016/j.envpol.2020.116147

https://phys.org/news/2020-12-consumed-species-mussels-microplastic...

Scientist tests new technology for removing, destroying 'forever ch...

University of Rhode Island hydrogeologist Thomas Boving and colleagues at EnChem Engineering Inc. are testing a proprietary new technology for quickly removing and destroying hazardous chemical compounds from soil and groundwater. If proven effective, the technology could soon be applied to cleaning up the abundant per- and polyfluoroalkyl substances, collectively referred to as PFAS and 'forever chemicals,' that contaminate drinking water supplies.

PFAS compounds have been in use for more than 60 years and are found in common household goods like non-stick cookware, stain-proof carpets and pizza boxes, as well as in firefighting foams and other industrial products. Because they do not break down easily in the environment, they find their way into human and animal tissues and can lead to many serious diseases.

First, they flushed the compounds out of the ground by pumping in a sugar molecule that has the ability to remove PFAS from the soil and groundwater. Then they pumped the solution out of the ground and hit it with a chemical oxidation process to destroy the compounds.

https://phys.org/news/2020-12-scientist-technology-chemicals.html?u...

**

Being Scientists Doesn’t Make Us Science Communicators

Effectively relating science to the public is a science in itself, and expertise on a topic doesn’t guarantee expertise in explaining it.

https://www.the-scientist.com/news-opinion/opinion-being-scientists...

Why are our tears salty?

Well, all fluids in our bodies have a little bit of salt in them. This salt is made into electricity to help our muscles contract and our brains to think. The amount of salt in our body fluids (like tears, sweat, and saliva) is about the same as the amount of salt in our blood — just under 1%, or about two teaspoons of salt per litre.

The saltiness of your tears can actually vary depending on what kind of tears your eyes are making.

That’s right, your eyes — or a part of your eyes called the lacrimal gland, to be precise — make three different types of tears. These are called basal tears, reflex tears and emotional tears.

• basal tears keep your eyes wet and stop nasty germs infecting your eyes
• reflex tears are made when your eyes need to wash away something harmful that gets in, such as smoke or a grain of sand
• emotional tears are the kind you cry when you’re feeling very happy or sad.

Basal tears and reflex tears have more salt in them than emotional tears, which is important for keeping your eyes healthy. Emotional tears contain more of other things, including a hormone (a special type of chemical in your body) that works like a natural painkiller. This might help to explain why we sometimes feel better after having a good cry.

https://theconversation.com/curious-kids-why-are-our-tears-salty-15...

These ‘beetlebots’ keep flying, even after crashing into poles

Astronomers May Have Detected The First Radio Signal From an Exoplanet

https://www.sciencealert.com/astronomers-detect-the-first-potential...

**

--

These Arctic squirrels recycle bits of their own bodies to survive winter

The secrets of the animals’ metabolism during hibernation could someday help human medicine

S.A. Rice et al. Nitrogen recycling buffers against ammonia toxicity from skeletal m.... Nature Metabolism. Published online December 7, 2020. doi: 10.1038/s42255-020-00312-4.

https://www.sciencenews.org/article/arctic-squirrels-recycle-protei...

--

Scientists take a step towards expanding the use of magnetic fluids...

Magnetic fluids are used in many different areas, including medicine, electronics, mechanical engineering, ecology, etc. Such a wide range of applications is explained by a number of its useful properties. Researchers from Peter the Great St.Petersburg Polytechnic University (SPbPU) in collaboration with colleagues from Jiangsu Normal University (JSNU) discovered new effects in magnetic fluids, which will increase its effectiveness for medical purposes in future. The results were published in Springer Proceedings in Physics.

--

When light and atoms share a common vibe

An especially counter-intuitive feature of quantum mechanics is that a single event can exist in a state of superposition—happening both here and there, or both today and tomorrow.

Science behind miracles

Exploring the role of prefrontal-amygdala brain circuits in social decision-making

In recent years, neuroscientists have been trying to understand the neural underpinnings of social behaviors and cognition. Studies on animal species, including primates and rodents, have identified a number of brain regions and neural circuits that may underpin social behaviors.

Researchers a have been conducting extensive research investigating the roles of the medial prefrontal cortex and the amygdala in social decision-making, particularly focusing on the interactions between different brain regions in the prefrontal-amygdala pathways. In a recent paper published in Nature Neuroscience, the researchers reviewed and summarized the evidence gathered in past studies that examined the neural mechanisms of social decision-making in humans, non-human primates and rodents.

Overall, the findings reviewed  the researchers highlight the crucial role of interactions between the medial prefrontal cortex and amygdala in the social cognition of a wide variety of animal species. The medial prefrontal cortex has previously been found to contribute to a number of sensorimotor, cognitive and emotional processes, while the amygdala is a region deep within the brain that integrates a number of emotions, emotional reactions and motivations.

Some recent studies also revealed that neural ensembles involved in the processing of information that is both related and unrelated to social communication can interact with one another. These interactions appear to facilitate or attenuate social functions, increasing or decreasing their prevalence over non-social functions.

 Prefrontal-amygdala circuits in social decision-making. Nature Neuroscience (2020). DOI: 10.1038/s41593-020-00738-9

https://medicalxpress.com/news/2020-12-exploring-role-prefrontal-am...

SARS-CoV-2-like particles very sensitive to temperature

Why do corona viruses become more active in winter?

A new study tested how temperatures and humidity affect the structure of individual SARS-Cov-2 virus-like particles on surfaces. They found that just moderate temperature increases broke down the virus' structure, while humidity had very little impact. In order to remain infectious, the SARS-Cov-2 membrane needs a specific web of proteins arranged in a particular order. When that structure falls apart, it becomes less infectious. The findings suggest that as temperatures begin to drop, particles on surfaces will remain infectious longer.

This is the first study to analyze the mechanics of the virus on an individual particle level, but the findings agree with large-scale observations of other coronaviruses that appear to infect more people during the winter months.

Temperature makes a huge difference, and that's what the researchers saw. To the point where the packaging of the virus was completely destroyed by even moderate temperature increases. They 

hey tested the virus-like particles on glass surfaces under both dry and humid conditions. Using atomic force microscopy they observed how, if at all, the structures changed. The scientists exposed samples to various temperatures under two conditions: with the particles inside a liquid buffer solution, and with the particles dried out in the open. In both liquid and bare conditions, elevating the temperature to about 93 degrees F for 30 minutes degraded the outer structure. The effect was stronger on the dry particles than on the liquid-protected ones. In contrast, surfaces at about 71 degrees F caused little to no damage, suggesting that particles in room temperature conditions or outside in cooler weather will remain infectious longer.

They saw very little difference under levels of humidity on surfaces, however the scientists stress that humidity likely does matter when the particles are in the air by affecting how fast the aerosols dry out. The research team is continuing to study the molecular details of virus-like particle degradation.

A. Sharma et al, Structural stability of SARS-CoV-2 virus like particles degrades with temperature, Biochemical and Biophysical Research Communications (2020). DOI: 10.1016/j.bbrc.2020.11.080

** https://medicalxpress.com/news/2020-12-sars-cov-like-particles-sens...

Forensic science: laser technique distinguishes human and animal blood

New research published recently could soon offer law enforcement another valuable crime scene tool—a quick and accurate way to distinguish human blood from animal blood.

In a proof-of-concept study researchers used laser technology to rapidly differentiate human blood samples from nearly a dozen animal species.

This could prove to be key in car crash investigations when the suspect is unsure if a human or animal was struck.

technique relies on Raman spectroscopy, which works by shining a laser on a dry blood sample and measuring the interaction. No two samples produce the same results, offering a unique measurement (similar to a fingerprint). The results are instantaneous and do not destroy the sample, preserving it for future testing.

In the new study researchers used attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy, a complementary technique to Raman spectroscopy, on 15 human blood samples and a total of 89 cat, dog, rabbit, horse, cow, pig, opossum and raccoon blood samples. Although each sample  appeared nearly identical to the naked eye, the ATR FT-IR spectroscopy analysis, coupled with advanced statistics, was able to classify them as human or animal with 100 percent accuracy.

Samples from three other species—deer, elk and ferret—were included to further test the statistical model, and were all correctly classified.

Ewelina Mistek-Morabito et al. Discrimination between human and animal blood by attenuated total reflection Fourier transform-infrared spectroscopy, Communications Chemistry (2020). DOI: 10.1038/s42004-020-00424-8

https://phys.org/news/2020-12-forensic-chemist-laser-technique-dist...

 Kangaroos really can 'talk' to us, study finds

Kangaroos can intentionally communicate with humans, research reveals

Animals that have never been domesticated, such as kangaroos, can intentionally communicate with humans, challenging the notion that this behavior is usually restricted to domesticated animals like dogs, horses or goats, a new study has found.

The research which involved kangaroos, marsupials that were never domesticated, at three locations across Australia, revealed that kangaroos gazed at a human when trying to access food which had been put in a closed box. The kangaroos used gazes to communicate with the human instead of attempting to open the box themselves, a behaviour that is usually expected for domesticated animals.

1. Alan G. McElligott, Kristine H. O'Keeffe, Alexandra C. Green. Kangaroos display gazing and gaze alternations during an unsolvable problem task. Biology Letters, 2020; 16 (12): 20200607 DOI: 10.1098/rsbl.2020.0607

https://www.sciencedaily.com/releases/2020/12/201217135258.htm

--

https://theconversation.com/coronavirus-new-variant-genomics-resear...

Coronavirus new variant – genomics researcher answers key questions

Colorful, magnetic Janus balls could help foil counterfeiters

Counterfeiters who sell knockoffs of popular shoes, handbags and other items are becoming increasingly sophisticated, forcing manufacturers to find new technologies to stay one step ahead. Now, researchers reporting in ACS Nano have developed tiny Janus balls that show their colored side under a magnetic field. These microparticles could be useful in inks for anti-counterfeiting tags, which could be verified with an ordinary magnet, the researchers say. 

Janus balls are microspheres that have two sides with distinct properties. Researchers wanted to make Janus balls out of two unmixable resins: one that contained magnetic nanoparticles, and another that contained silica particles. The magnetic side of the ball would also contain carbon black, causing that hemisphere to appear dark, whereas the silica particles on the other side of the ball would self-assemble into a crystalline lattice, producing structural colors. The result would be tiny balls that normally have their black sides facing up, except when a magnetic field causes them to flip to their colorful sides.

To make Janus balls, the researchers used a microfluidic device to unite drops of the two resins, with a surfactant added to stabilize the joined drops into a spherical shape. Because the silica-containing colored side of the drops was heavier than the black magnetic side, the force of gravity caused the black side to spontaneously face upward, like a roly-poly toy, when the balls were placed in water. Then, the researchers permanently aligned the magnetic nanoparticles in the balls in the same direction. By applying a magnetic field in the opposite direction, they could flip the balls to their colored sides. The researchers made red and green Janus balls by using different sizes of silica particles, with their magnetic nanoparticles aligned in opposite directions. By changing the direction of the applied magnetic field, they could change the colors of 3D-printed chameleon and butterfly shapes. Using different colors and orientations of Janus balls in inks could produce sophisticated, user-interactive anti-counterfeiting tags, the researchers say.

https://www.acs.org/content/acs/en/pressroom/presspacs/2020/acs-pre...

Quantum Experiment Reveals Particles Can Form Collectives Out of Almost Nothing

How many particles do you need before individual atoms start behaving collectively? According to new research, the number is incredibly low. As few as six atoms will start transitioning into a macroscopic system, under the right conditions.

Using a specially designed ultra-cold laser trap, physicists observed the quantum precursor of the transition from a normal to a superfluid phase – offering a way to study the emergence of collective atomic behaviour and the limits of macroscopic systems.

Many-body physics is the field that seeks to describe and understand the collective behaviour of large numbers of particles: a bucket of water, for example, or a canister of gas. We can describe these substances in terms of their density, or their temperature – the way the substance is acting as a whole.

These are called macroscopic or many-body systems, and we can't understand them by just studying the behaviour of individual atoms or molecules. Rather, their behaviour emerges from the interactions between particles that individually do not have the same properties of the system as a whole.

Some examples of macroscopic behaviours that can't be described microscopically include collective excitations, such as the phonons that oscillate atoms in a crystal lattice. Phase transitions are another example – when a substance transitions from one phase to another – such as when ice melts into liquid, for example, or when liquid evaporates into a gas.

https://www.nature.com/articles/s41586-020-2936-y

https://www.sciencealert.com/quantum-simulator-reveals-that-phase-t...

 Here we observe the few-body precursor of a quantum phase transition from a normal to a superfluid phase. The transition is signalled by the softening of the mode associated with amplitude vibrations of the order parameter, usually referred to as a Higgs mode⁷. We achieve fine control over ultracold fermions confined to two-dimensional harmonic potentials and prepare closed-shell configurations of 2, 6 and 12 fermionic atoms in the ground state with high fidelity. 

Fast walking in narrow corridors can increase COVID-19 transmission risk

Computational simulations have been used to accurately predict airflow and droplet dispersal patterns in situations where COVID-19 might be spread. In the journal Physics of Fluids, results show the importance of the shape of the space in modeling how virus-laden droplets move through the air.

The simulations are used to determine flow patterns behind a walking individual in spaces of different shape. The results reveal a higher transmission risk for children in some instances, such as behind quickly moving people in a long narrow hallway.

Previous investigations using this simulation technique have helped scientists understand the influence of objects, like glass barriers, windows, air conditioners, and toilets, on airflow patterns and virus spread. The previous simulations have usually assumed a large, open indoor space but have not considered the effect of nearby walls, like those that might exist in a narrow corridor.

If a person walking in a corridor coughs, their breath expels droplets that travel around and behind their body, forming a wake in the way a boat forms a wake in water as it travels. The investigation revealed the existence of a "re-circulation bubble" directly behind the person's torso and a long wake streaming out behind them at approximately waist height.

The flow patterns found are strongly related to the shape of the human body. At 2 meters downstream, the wake is almost negligible at mouth height and leg height but is still visible at waist height. 

Once the airflow patterns were determined, the investigation modeled the dispersal of a cloud of droplets expelled from the simulated person's mouth. The shape of the space surrounding the moving person is particularly critical for this part of the calculation.

Two types of dispersal modes were found. In one mode, the cloud of droplets detaches from the moving person and floats far behind that individual, creating a floating bubble of virus-laden droplets. In the other mode, the cloud is attached to the person's back, trailing behind them like a tail as they move through the space.

For the detached mode, the droplet concentration is much higher than for the attached mode, five seconds after a cough. This poses a great challenge in determining a safe social distance in places like a very narrow corridor, where a person may inhale viral droplets even if the patient is far in front of him or her.

The danger is particularly great for children, since in both modes, the cloud of droplets hovers at a distance above the ground that is about half the height of the infected person—in other words, at mouth level for children.

"Effects of space sizes on the dispersion of cough-generated droplets from a walking person," Physics of Fluids (2020). aip.scitation.org/doi/10.1063/5.0034874

https://phys.org/news/2020-12-fast-narrow-corridors-covid-transmiss...

AI-powered microscope could check cancer margins in minutes

When surgeons remove cancer, one of the first questions is, “Did they get it all?” Researchers from Rice University and the University of Texas MD Anderson Cancer Center have created a new microscope that can quickly and inexpensively image large tissue sections, potentially during surgery, to find the answer. The microscope can rapidly image relatively thick pieces of tissue with cellular resolution, and could allow surgeons to inspect the margins of tumors within minutes of their removal. It was created by engineers and applied physicists at Rice and is described in a study published this week in the Proceedings of the National Academy of Sciences.

http://news.rice.edu/2020/12/17/ai-po...

Evolution of a killer: How African Salmonella made the leap from gut to bloodstream

Scientists have exploited the combined power of genomics and epidemiology to understand how a type of Salmonella bacteria evolved to kill hundreds of thousands of immunocompromised people.

Bloodstream infections caused by a drug-resistant type of Salmonella Typhimurium called ST313 are a major public health concern in Africa, where the disease is endemic and causes ~50,000 deaths each year. What was missing was an understanding of the timing of the major evolutionary events that equipped African Salmonella to cause bloodstream infections in humans.

A team of researchers  sampled two comprehensive collections of Salmonella isolates from African patients with bloodstream infections, spanning 1966 to 2018, to piece together the evolutionary journey of the Salmonella over 50 years of human infections in Africa, including the discovery of a new lineage of antibiotic-susceptible ST313.

In the study, scientists sequenced the genomes of 680 Salmonella isolates, from archives kept by the Malawi Liverpool Wellcome Trust (MLW) clinical research programme and the Institute Pasteur, and used them to uncover the timeline of crucial genetic events responsible for the infection of immunocompromised humans by S. Typhimurium ST313. Mutations that influenced gene function during the evolution of ST313 were identified for the first time.

The team also discovered a new antibiotic-susceptible lineage of ST313 that emerged in Malawi in 2016 and is closely related to Salmonella variants that cause stomach infections in the United Kingdom and Brazil. The researchers speculate that changes in antibiotic usage in Malawi between 2002 and 2015 could have created a window of opportunity for the emergence of this new antibiotic-susceptible ST313 lineage.

Stepwise evolution of Salmonella Typhimurium ST313 causing bloodstream infection in Africa, Nature Microbiology (2020). DOI: 10.1038/s41564-020-00836-1 , www.nature.com/articles/s41564-020-00836-1

https://phys.org/news/2020-12-evolution-killer-african-salmonella-g...

When T-cells of our immune system become active, tiny traction forc...

When T-cells of our immune system become active, tiny traction forces at the molecular level play an important role. They have now been studied at TU Wien.

--

Brazilian forests found to be transitioning from carbon sinks to ca...

A team of researchers affiliated with several institutions in Brazil has found that some non-Amazonian forests in Brazil have already begun to transition from carbon sinks to carbon sources. In their paper published in the journal Science Advances, the group describes their 33-year study of deciduous, semi-deciduous and evergreen forests in Brazil's state of Minas Gerais.

**

Current food production systems could mean far-reaching habitat loss

The global food system could drive rapid and widespread biodiversity loss if not changed, new research has found.

The findings show that the global food system will need to be transformed to prevent habitat loss across the world. It shows that what we eat and how it is produced will need to change rapidly and dramatically to prevent widespread and severe biodiversity losses.

--

The study estimated how food systems would affect biodiversity at a finer spatial scale than previous research (2.25 km²), making the results more relevant to conservation action by highlighting exactly which species and landscapes are likely to be threatened.

It did so by linking projections of how much agricultural land each country will need with a new model that estimates where agricultural expansion and abandonment are most likely to occur.

Proactive conservation to prevent habitat losses to agricultural expansion, Nature Sustainability (2020). DOI: 10.1038/s41893-020-00656-5 , www.nature.com/articles/s41893-020-00656-5

https://phys.org/news/2020-12-current-food-production-far-reaching-...