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Despite being considered as one of the best studied spiders in the Palearctic, the orb-weaver spiders (family Araneidae) remain poorly known in the central parts of the ecozone. To bridge the knowledge gaps, an international research team of researchers took to the Caucasus, Middle East and Central Asia to study two of those genera: Araniella and Neoscona.

As a result, in their article, recently published in the open-access scientific journal ZooKeys, arachnologists Alireza Zamani (University of Turku, Finland), Yuri M. Marusik (Institute for Biological Problems of the North RAS, Russia) and Anna Šestáková (The Western Slovakian Museum, Slovakia) describe three new to science species, where one: Araniella villanii - carries the name of the flamboyant French mathematician and spider aficionado Cédric Villani, dubbed the "Lady Gaga of Mathematics". Even if unknown until now, the species turned out to have a wide distribution ranging from southwestern Iran to eastern Kazakhstan and northern India.

"It's a well-known fact within the arachnological community that spiders are masters of mathematics and architecture", explains lead author of the study Alireza Zamani. "Orb-web spiders, in particular, tend to build beautiful and architecturally aesthetic webs, some of which are formed in spirals in line with the repetitive pattern of the golden ratio."

The web of the garden orb-web spider Araneus diadematus, for example, usually has 25 to 30 radial threads forming an astonishingly precise angle of about 15°, which the spider carefully measures using its front legs. According to scientific observations, if the front legs are removed, the regularity of the angles between adjacent radial threads is impaired.

For these and many other reasons, spiders must have been an inspiration for mathematicians like Cédric Villani, who has publicly shown a mysterious love for these arachnids. Awarded the Fields Medal (some say it's the Mathematics equivalent of the Nobel Prize) in 2010, and having served as the director of Sorbonne University's Institut Henri Poincaré from 2009 to 2017, the Frenchman's love for spiders is quite evident thanks to the constant presence of a spider brooch on his lapel. Although he has never explained the reason behind his appreciation of these eight-legged wonders, now he has a real, even scientifically sound connection to them in the real world.

Apart from Araniella villanii, whose scientific name honours the prominent scientist and recognises his love for spiders, the other two newly described species also have a story behind their names. One of them: Neoscona isatis, discovered in central Iran, was named after the historical name of its type locality; and Araniella mithra, known from northwestern, central and southwestern Iran, was named after Mithra, the god of light in the ancient Indo-Iranian mythology.

Curiously, spiders in the genus Araniella are green in colour due to certain bile pigments (biliverdin) that make them very difficult to spot in their natural habitat, as they live mostly on leaves.

"I met Mr. Villani in May 2015 at University of Tehran, where he was an invited speaker. We got to briefly talk about our shared interest in spiders, and I had the opportunity to present him an Iranian wolf spider as a souvenir!" recalls Zamani.

"It's important to note that, with the efforts of taxonomists, new species are being discovered and described with an average rate of 18,000 species per year, but simultaneously both known and undescribed species go extinct due to human activities, with the current rate being within or even higher than the range of the newly described ones. A first step towards conservation of biodiversity includes taxonomic research to document species and to define hotspots of species diversity in order to protect such carefully selected habitats," he points out.

"However, with the current situation of low funding for taxonomic research, the number of students doing taxonomic research is in severe decline and the current average 'shelf life' (between discovery and description) of a new species remains at about 21 years. Araniella villanii is a great example of how much we don't know about our biodiversity."

Despite being discovered all the time, new species mostly have very restricted ranges and are only known from a few nearby localities. Orb-weaver spiders have very good dispersal abilities, and it is relatively uncommon to detect new species of them.

"Araniella villanii is known from a few localities in southwestern Iran, eastern Kazakhstan and northern India, a distribution range covering at least ten countries, and yet the species was unknown to science until now. I think that the message that this particular discovery implies is that while there are such widely-distributed undescribed species out there, we need more and more taxonomic research, both in the field and in the natural history museum collections, which house a considerable number of undescribed species, in order to preserve the remaining biodiversity on earth, before it's too late.

Seriously ill patients require serious, higher-level care, and sometimes patients must be transferred from one hospital to another to allow access to that care. For example, a patient may require procedures, tests or expertise that only an academic medical center can deliver. The benefits of such interhospital transfer (IHT) are believed to outweigh the risks, but at the same time, studies of national databases indicate that transferred patients have a higher risk of dying than patients admitted to the hospital locally through the emergency department. And with about 1.6 million patients being transferred between hospitals each year, this safety risk needs to be resolved as a top priority.

While national studies demonstrate worse outcomes for IHT patients, these studies are unable to control for patient-level details such as individual vital signs, laboratory values and specific disease processes, so it is difficult to conclude whether the worse outcomes are related to the transfer process itself or to undefined variables. A few detailed single-center studies controlling for these patient-level characteristics were performed in the 1980s and 1990s, but health care has changed enormously since then.

Marc Heincelman, M.D., a hospitalist and assistant professor at the Medical University of South Carolina (MUSC), notes that patient safety has become a major target over the last two decades, which has led to robust electronic health records, quality improvement initiatives focused on patient safety, and specialists -- hospitalists -- focused solely on inpatients.

Heincelman explains, "With the implementation of electronic health records, expansion of hospitalists, and enhanced focus on quality improvement and safety, further studies needed to be performed to look at patient-level characteristics associated with the transfer process."

He thus chose to perform an updated study, recently published by the Journal of General Internal Medicine, to examine the safety of IHT within the modern health care system. He and his colleagues also wanted to examine the relationship between IHT and mortality at a detailed level that considered many patient characteristics. They wanted to determine if patient factors could explain why the risk of mortality increased or if the higher risk was even truly there once the patient factors were considered.

The research team started by separating data for about 9,000 patients admitted to the hospital between 2013 and 2014 into groups based on how the patients were admitted -- via IHT, the emergency department or a clinic. Using data modeling with increasing levels of refinement, the researchers next examined the relationship between IHT and the risk of death. The first modeling step considered both the IHT status of the patients and the hospital service that received them. The second included patient demographic information, such as age, race, gender, zip code, income and insurance status. The third added specific disease processes, such as heart failure, kidney dysfunction, diabetes and others. And the fourth looked at individual vital signs and laboratory data present on hospital admission.

"We found two interesting things," says Heincelman. "First, detailed patient-level variables do play a role in predicting mortality, and second, even after controlling for those variables, interhospital transfer itself is still associated with inpatient mortality."

By looking at multiple layers of patient characteristics, the study pinpointed that vital signs and lab data play a role in the risk of mortality in IHT patients. While the overall mortality risk was about 2 times higher for IHT patients than for patients admitted via the emergency department, that risk changed to 1.7 times after patients' vital signs and laboratory values were considered.

Heincelman points out that this observation already provides an opportunity for improvement. "It allows the accepting physician to just take a moment and ask, 'Is there anything we need to do at the initial institution to stabilize them before we transfer them?'"

But even allowing for the effect of vital signs and lab values, outcomes for transfer patients are still worse than those for patients admitted through the emergency department. The reasons for this association are still unknown, but Heincelman plans to dig deeper to learn what other variables may be at play. He hopes that this will lead to better outcomes for patients who need to be transferred from one hospital to another.

He notes, "A seriously ill patient at a community hospital is still at risk for mortality there. So if we think that transfer is the right thing for the patient we're going to do everything we can for them. The question is how can we make it as safe as possible, and the hope is that we can reduce the risk."

Heincelman and colleagues hypothesize that many patients who require transfer are sicker than current scoring models indicate. But they also believe that the transfer process itself may be risky. They next plan to examine this process in detail, looking at factors like the day and time of transfer, the busyness of the admitting service during transfer, how much time elapses between the hospital accepting the patient and the actual arrival time, and communications between the doctor sending the patient and the doctor receiving the patient on the other end.

"I still think that the patients are inherently sicker, we just don't have a way to measure their illness with the models that we currently have," he said. "But I also think that there are areas within the transfer process that can be improved for safety purposes."

An international study by Monash University has discovered wild grey seals can clap their flippers underwater during breeding season.

This is regarded as a show of strength that warns off competitors and advertises themselves to potential mates.

The video footage taken by researchers shows a male grey seal clapping in the wild, producing a gunshot-like 'crack'.

Marine mammals like whales and seals usually communicate vocally using calls and whistles.

But now a Monash University-led international study has discovered that wild grey seals can also clap their flippers underwater during the breeding season, as a show of strength that warns off competitors and advertises to potential mates.

This is the first time a seal has been seen clapping completely underwater using its front flippers.

"The discovery of 'clapping seals' might not seem that surprising, after all, they're famous for clapping in zoos and aquaria," said lead study author Dr David Hocking from Monash University's School of Biological Sciences.

"But where zoo animals are often trained to clap for our entertainment - these grey seals are doing it in the wild of their own accord."

The research, published today in the journal Marine Mammal Science, is based on video footage collected by naturalist Dr Ben Burville, a Visiting Researcher with Newcastle University, UK.

The footage - which took Dr Burville 17 years of diving to catch on film - shows a male grey seal clapping its paw-like flippers to produce a gunshot-like 'crack!' sound.

"The clap was incredibly loud and at first I found it hard to believe what I had seen," Dr Burville said.

"How could a seal make such a loud clap underwater with no air to compress between its flippers?"

"Other marine mammal species can produce similar types of percussive sound by slapping the water with their body or tail," said Associate Professor Alistair Evans from Monash University, who was also involved in the study.

The loud high-frequency noise produced by clapping cuts through background noise, sending out a clear signal to any other seals in the area.

"Depending on the context, the claps may help to ward off competitors and/or attract potential mates," Dr Hocking said.

"Think of a chest-beating male gorilla, for example. Like seal claps, those chest beats carry two messages: I am strong, stay away; and I am strong, my genes are good."

Dr Hocking said clapping seals demonstrates just how much there still is to learn about the animals living around us.

Clapping appears to be an important social behaviour for grey seals, so anything that disturbed it could impact breeding success and survival for this species.

"Human noise pollution is known to interfere with other forms of marine mammal communication, including whale song," Dr Hocking said.

"But if we do not know a behaviour exists, we cannot easily act to protect it."

Understanding the animals around us better may just help us to protect them, and their way of life.

A novel approach to reverse the progression of healthy cells to malignant ones may offer a more effective way to eradicate colorectal cancer cells with far fewer side effects, according to a team of researchers based in South Korea.

Colorectal cancer, or cancer of the colon, is the third most common cancer in men and the second most common in women worldwide. South Korea has the second highest incident rate of colorectal cancer in the world, topped only by Hungary, according to the World Cancer Research Fund.

Their results were published as a featured cover article on January 2 in Molecular Cancer Research, a journal of the American Association for Cancer Research.

Led by Kwang-Hyun Cho, a professor and associate vice president of research at KAIST , the researchers used a computational framework to analyze healthy colon cells and colorectal cancer cells. They found that some master regulator proteins involved in cellular replication helped healthy colon cells mature, or differentiate into their specific cell type, and remain healthy. One particular protein, called SETDB1, suppressed the helpful proteins, forcing new cells to remain in a state of immaturity with the potential to become cancerous.

"This suggests that differentiated cells have an inherent resistance mechanism against malignant transformation and indicates that cellular reprogramming is indispensable for malignancy," said Cho. "We speculated that malignant properties might be eradicated if the tissue-specific gene expression is reinstated -- if we repress SETDB1 and allow the colon cells to mature and differentiate as they would normally."

Using human-derived cells, Cho and his team targeted the tissue-specific gene expression programs identified in their computational analysis. These are the blueprints for the proteins that eventually help immature cells differentiate into tissue-specific cell types, such as colon cells. When a person has a genetic mutation, or has exposure to certain environmental factors, this process can go awry, leading to an overexpression of unhelpful proteins, such as SEDTB1.

The researchers specifically reduced the amount of SEDTB1 in these tissue-specific gene expression programs, which allowed the cells to mature and fully differentiate into colon cells.

"Our experiment also shows that SETDB1 depletion combined with cytotoxic drugs might be potentially beneficial to anticancer treatment," Cho said. Cytotoxic drugs are often used for cancer treatment because the type of medicine contains chemicals that are toxic to cancer cells which can prevent them from replicating or growing. He noted that this combination could be more effective in treating cancer by transforming the cancer cell state into a less malignant or resistant state. He eventually pursues a cancer reversion therapy alone instead of conventional cytotoxic drug therapy since the cancer reversion therapy can provide a much less painful experience for patients with cancer who often have severe side effects from treatments intended to kill off cancerous cells, such as chemotherapy.

The researchers plan to continue studying how to return cancer cells to healthier states, with the ultimate goal of translating their work to therapeutic treatment for patients with colorectal cancer.

"I think our study of cancer reversion would eventually change the current medical practice of treating cancer toward the direction of keeping the patient's quality of life while minimizing the side effects of current anti-cancer therapies," Cho said.

The research - which was undertaken at the University of York - also suggests there was no single point of origin for the world's oldest pottery.

Academics extracted and analysed ancient fats and lipids that had been preserved in pieces of ancient pottery - found at a number of sites on the Amur River in Russia - whose dates ranged between 16,000 and 12,000 years ago.

Professor Oliver Craig, Director of the BioArch Lab at the University of York, where the analysis was conducted, said: "This study illustrates the exciting potential of new methods in archaeological science: we can extract and interpret the remains of meals that were cooked in pots over 16,000 years ago.

"It is interesting that pottery emerges during these very cold periods, and not during the comparatively warmer interstadials when forest resources, such as game and nuts, were more available."

Why these pots were first invented in the final stages of the last Ice Age has long been a mystery, as well as the kinds of food that were being prepared in them.

Researchers also examined pottery found from the Osipovka culture also on the Amur River. Analysis proved that pottery from there had been used to process fish, most likely migratory salmon, which offered local hunters an alternative food source during periods of major climatic fluctuation. An identical scenario was identified by the same research group in neighbouring islands of Japan.

The new study demonstrates that the world's oldest clay cooking pots were being made in very different ways in different parts of Northeast Asia, indicating a "parallel" process of innovation, where separate groups that had no contact with each other started to move towards similar kinds of technological solutions in order to survive.

Lead author, Dr Shinya Shoda, of the National Research Institute for Cultural Properties in Nara, Japan said: "We are very pleased with these latest results because they close a major gap in our understanding of why the world's oldest pottery was invented in different parts of Northeast Asia in the Late Glacial Period, and also the contrasting ways in which it was being used by these ancient hunter-gatherers.

"There are some striking parallels with the way in which early pottery was used in Japan, but also some important differences that we had not expected. This leaves many new questions that we will follow up with future research."

Professor Peter Jordan, senior author of the study at the Arctic Centre and Groningen Institute of Archaeology, University of Groningen, the Netherlands said: "The insights are particularly interesting because they suggest that there was no single "origin point" for the world's oldest pottery. We are starting to understand that very different pottery traditions were emerging around the same time but in different places, and that the pots were being used to process very different sets of resources.

"This appears to be a process of "parallel innovation" during a period of major climatic uncertainty, with separate communities facing common threats and reaching similar technological solutions."

The last Ice Age reached its deepest point between 26,000 to 20,000 years ago, forcing humans to abandon northern regions, including large parts of Siberia. From around 19,000 years ago, temperatures slowly started to warm again, encouraging small bands of hunters to move back into these vast empty landscapes.

When an infected tsetse fly bites humans or other mammals to feed on their blood, microscopic parasites (African trypanosomes) in the fly's saliva are transferred. The unfortunate recipient of the bite, once infected, often faces severe health consequences, even death.

Unfortunately, current public health approaches to control African sleeping sickness are limited. Diagnosis and treatment are especially difficult in remote areas of sub-Saharan Africa where the disease is pronounced. To complicate matters further, the trypanosomes have evolved so that they can evade their victim's immune response and sustain an infection.

But a promising disease control strategy being developed by researchers at the Yale School of Public Health might overcome these challenges. It involves blocking the transmission of parasites at the point of entry: the bite site.

Until recently, examining molecular and biochemical metacyclic cells (the infectious form of the parasite that is deposited at the bite site) has been hampered by the relatively small number of parasites present in saliva and by the presence of various non-infectious parasite developmental forms in the fly's salivary glands.

In a new study published in the journal PNAS, a team of researchers led by Yale School of Public Health Professor Serap Aksoy describe how they performed single-cell RNA sequencing of individual parasite cells (T. brucei brucei) from infected tsetse salivary glands. The cells were sorted into distinct developmental forms, the data from which provides unique and high-resolution insights into the molecular processes that give rise to infective metacyclic parasites transmitted at the host bite site. The study also identified a new family of surface proteins (known as Fam10), which are uniquely associated with the infectious metacyclic parasites. Vaccination of mice with one member of this family (SGM1.7) significantly reduced parasitemia early during the infection process. This indicates that Fam10 proteins are promising vaccine candidates for blocking transmission of the parasite at the bite site.

This has never been done before and it marks an important step toward curbing the severe threat posed by the tsetse fly and its parasites.

"The ability of African trypanosomiases parasites to bypass the mammalian immune responses by changing their surface coat proteins has hampered development of vaccines. Our discovery has opened up a new chapter into these investigations," said Aksoy, a member of the Yale School of Public Health's Department of Epidemiology (Microbial Diseases).

Future studies will test the efficacy of multivalent protein vaccines that target the trypanosome Fam10 protein family to enhance transmission blocking. The Fam10 proteins are also found on the surface of other disease-causing African trypanosomes, indicating their potential use for combatting a plethora of devastating tsetse-transmitted infections.

According to the Centers for Disease Control and Prevention, West African trypanosomiasis, which is more widespread than a second form of the disease known as East African trypanosomiasis, results in 7,000 to10,000 new human cases each year, though many cases are not recognized or reported and the actual number of cases is likely far higher.

The disease's toll on domesticated animals, meanwhile, is rampant throughout sub-Saharan Africa.

A Northwestern University research team has revealed a new approach to conducting chemical reactions -- one that doesn't require direct contact with a catalyst.

In typical catalytic reactions, the catalyst -- the substance that increases the rate of a chemical reaction --and the substrate reactants must be present in the same medium and in direct contact with one another to produce a reaction. The research team's new system demonstrates a chemical reaction produced through an intermediary created by a separate chemical reaction. The findings could have applications in environmental remediation and fuel production.

"Improving our understanding of the catalyst-intermediary-reaction relationship could greatly expand the possibilities of catalytic reactions," said Harold Kung, Walter P. Murphy Professor of Chemical and Biological Engineering at the McCormick School of Engineering, who led the research. "By learning that a chemical reaction can proceed without direct contact with a catalyst, we open the door to using catalysts from earth-abundant elements to perform reactions they normally wouldn't catalyze."

The study, titled "Noncontact Catalysis: Initiation of Selective Ethylbenzene Oxidation by Au Cluster-Facilitated Cyclooctene Epoxidation," was published January 31 in the journal Science Advances. Mayfair Kung, a research associate professor of chemical and biological engineering, was a co-corresponding author on the paper. Linda Broadbelt, Sarah Rebecca Roland Professor of Chemical and Biological Engineering and associate dean for research, also contributed to the study.

The research builds on previous work in which the team investigated the selective oxidation of cyclooctene--a type of hydrocarbon -- using gold (Au) as a catalyst. The study revealed that the reaction was catalyzed by dissolved gold nanoclusters. Surprised, the researchers set out to investigate how well the gold clusters could catalyze selective oxidation of other hydrocarbons.

Using a platform they developed called Noncontact Catalysis System (NCCS), the researchers tested the effectiveness of a gold catalyst against ethylbenzene, an organic compound prevalent in the production of many plastics. While ethylbenzene did not undergo any reaction in the presence of the gold clusters, the team found that when the gold clusters reacted with the cyclooctene, the resulting molecule provided the necessary intermediary to produce ethylbenzene oxidation.

"The two reactions are totally independent of each other," Kung said. "We saw that the gold nanoclusters and the cyclooctene were ineffective to oxidize the ethylbenzene on their own. Direct contact didn't cause the reaction to proceed. Thus, the intermediary reaction was necessary."

By demonstrating how normally ineffective catalysts can be made effective in a reaction through an intermediary, the researchers believe it is possible to design systems using catalysts that are physically separated from a reaction medium that would otherwise harm the catalyst. This new approach could provide an effective workaround in environmental remediation, such as cleaning a contaminated river, where some components in the water may be poisonous to the catalyst.

"You could use a membrane to separate the catalyst from the medium, then use the catalyst to generate an intermediary that can pass through the membrane and degrade the contaminant in a safer way," Kung said.

The work also opens the door to greater freedom in industrial chemical production. An ability to conduct coupled parallel reactions without the constraints of traditional stoichiometry -- the strict quantity-based relationships among reaction products -- could make industrial hydrocarbon co-oxidation processes more versatile, efficient, and cost effective. These processes are vital in the production of gasoline and conversion of natural gas to liquid fuel and other chemicals.

The research team's next step is to determine gold's reactivity against other hydrocarbons of different bond strengths. They also hope to learn whether similar phenomenon can be applied to other metals, such as silver or copper.

"We are not quite there yet, but once we understand the relationship between the reactivity of gold clusters toward hydrocarbons and bond strengths, we will be able to predict and design other chemical reaction systems," Kung said.

Urbana, IL -- Fundamental research in condensed matter physics has driven tremendous advances in modern electronic capabilities. Transistors, optical fiber, LEDs, magnetic storage media, plasma displays, semi-conductors, superconductors--the list of technologies born of fundamental research in condensed matter physics is staggering. Scientists working in this field continue to explore and discover surprising novel phenomena that hold promise for tomorrow's technological advances.

An important line of inquiry in this field involves topology--a mathematical framework for describing surface states that remain stable even when the material is deformed by stretching or twisting. The inherent stability of topological surface states has implications for a range of applications in electronics and spintronics.

Now, an international team of scientists has discovered an exotic new form of topological state in a large class of 3D semi-metallic crystals called Dirac semimetals. The researchers developed extensive mathematical machinery to bridge the gap between theoretical models with forms of "higher-order" topology (topology that manifests only at the boundary of a boundary) and the physical behavior of electrons in real materials.

The team comprises scientists at Princeton University, including postdoctoral researcher Dr. Benjamin Wieder, Chemistry Professor Leslie Schoop, and Physics Professor Andrei Bernevig; at the University of Illinois at Urbana-Champaign, Physics Professor Barry Bradlyn; at the Institute of Physics Chinese Academy of Sciences in Beijing, Physics Professor Zhijun Wang; at State University of New York at Stony Brook, Physics Professor Jennifer Cano (Cano is also affiliated with the Simons Foundation's Flatiron Institute); and at Hong Kong University of Science and Technology, Physics Professor Xi Dai. The team's results were published in the journal Nature Communications on January 31, 2020.

Over the past decade, Dirac and Weyl fermions have been predicted and experimentally confirmed in a number of solid-state materials, most notably in crystalline tantalum arsenide (TaAs), the first-discovered topological Weyl fermion semimetal. Several researchers observed that TaAs exhibits 2D topological surface states known as "Fermi arcs." But similar phenomena observed in Dirac fermion semimetals have eluded understanding, until now.

What is a Fermi arc? In the context of semimetals, it's a surface state behaving like one-half of a two-dimensional metal; the other half is found on a different surface.

Bradlyn notes, "This is not something that's possible in a purely 2D system, and can only happen as a function of the topological nature of a crystal. In this work, we found that the Fermi arcs are confined to the 1D hinges in Dirac semimetals." In earlier work, Dai, Bernevig, and colleagues experimentally demonstrated that the 2D surfaces of Weyl semimetals must host Fermi arcs, regardless of the details of the surface, as a topological consequence of the Weyl points (fermions) present deep within the bulk of the crystal. This was first theoretically predicted by Vishwanath, et al.

"Weyl semimetals have layers like onions," notes Dai. "It's remarkable that you can keep peeling the surface of TaAs, but the arcs are always there."

Researchers have also observed arc-like surface states in Dirac semimetals, but attempts to develop a similar mathematical relationship between such surface states and Dirac fermions in the bulk of the material have been unsuccessful: it was clear the Dirac surface states arise from a different, unrelated mechanism, and it was concluded the Dirac surface states were not topologically protected.

In the current study, the researchers were surprised to encounter Dirac fermions that appeared to exhibit topologically protected surface states, contradicting this conclusion. Working on models of Dirac semimetals derived from topological quadrupole insulators--higher-order topological systems recently discovered by Bernevig in collaboration with Illinois Physics Professor Taylor Hughes--they found that this new class of materials exhibits robust, conducting electronic states in 1D, or two fewer dimensions than the bulk 3D Dirac points.

Initially confounded by the mechanism through which these "hinge" states appeared, the researchers worked to develop an extensive, exactly solvable model for the bound states of topological quadrupoles and Dirac semimetals. The researchers found that, in Dirac semimetals, Fermi arcs are generated by a different mechanism than the arcs in Weyl semimetals.

"In addition to settling the decades-old problem of whether condensed matter Dirac fermions have topological surface states," Wieder notes, "we demonstrated that Dirac semimetals represent one of the first-solid state materials hosting signatures of topological quadrupoles."

Bradlyn adds, "Unlike Weyl semimetals, whose surface states are cousins of the surfaces of topological insulators, we have shown that Dirac semimetals can host surface states that are cousins of the corner states of higher-order topological insulators."

Bradlyn describes the team's methodology: "We took a three pronged approach to sort things out. First, we constructed some toy models for systems that we expected to have these properties, inspired by previous work on higher-order topological systems in 2D, and using group theory to enforce constraints in three dimensions. This was done primarily by Dr. Wieder, Prof. Cano, and myself.

"Second, Dr. Wieder and I carried out a more abstract theoretical analysis of systems in two dimensions, deriving the conditions for which they are required to exhibit hinge states, even outside of toy models."

"Third, we performed an analysis of known materials, combining Professor Leslie Schoop's chemistry intuition, our symmetry constraints, and ab initio calculations from Professor Zhijun Wang to show that our hinge arc states should be visible in real materials."

When the dust settled, the team found that almost all condensed matter Dirac semimetals should in fact exhibit hinge states.

"Our work provides a physically observable signature of the topological nature of Dirac fermions, which was previously ambiguous," notes Cano.

Bradlyn adds, "It's clear that numerous previously studied Dirac semimetals actually do have topological boundary states, if one looks in the right place."

Through first-principles calculations, the researchers theoretically demonstrated the existence of overlooked hinge states on the edges of known Dirac semimetals, including the prototypical material, cadmium arsenide (Cd3As2).

Bernevig comments, "With an amazing team combining skills from theoretical physics, first-principles calculations, and chemistry, we were able to demonstrate the connection between higher-order topology in two dimensions and Dirac semimetals in three dimensions, for the first time."

The team's findings have implications for the development of new technologies, including in spintronics, because the hinge states can be converted into edge states whose direction of propagation is tied to their spin, much like the edge states of a 2D topological insulator. Additionally, nanorods of higher-order topological semimetals could realize topological superconductivity on their surfaces when proximitized with conventional superconductors, potentially realizing multiple Majorana fermions, which have been proposed as ingredients for achieving fault-tolerant quantum computation.

University of Groningen physicists have visualized hydrogen at the titanium/titanium hydride interface using a transmission electron microscope. Using a new technique, they succeeded in visualizing both the metal and the hydrogen atoms in a single image, allowing them to test different theoretical models that describe the interface structure. The results were published on 31 January in the journal Science Advances.

To understand the properties of materials, it is often vital to observe their structure at an atomic resolution. Visualizing atoms using a transmission electron microscope (TEM) is possible; however, so far, no one has succeeded in producing proper images of both heavy atoms and the lightest one of all (hydrogen) together. This is exactly what University of Groningen Professor of Nanostructured Materials Bart Kooi and his colleagues have done. They used a new TEM with capabilities that made it possible to produce images of both titanium and hydrogen atoms at the titanium/titanium hydride interface.

Hydrogen atoms

The resulting pictures show how columns of hydrogen atoms fill spaces between the titanium atoms, distorting the crystal structure. They occupy half of the spaces, something which was predicted earlier. 'In the 1980s, three different models were proposed for the position of hydrogen at the metal/metal hydride interface,' says Kooi. 'We were now able to see for ourselves which model was correct.'

To create the metal/metal hydride interface, Kooi and his colleagues started out with titanium crystals. Atomic hydrogen was then infused and penetrated the titanium in very thin wedges, forming tiny metal hydride crystals. 'In these wedges, the numbers of hydrogen and titanium atoms are the same,' Kooi explains. 'The penetration of hydrogen creates a high pressure inside the crystal. The very thin hydride plates cause hydrogen embrittlement in metals, for example inside nuclear reactors.' The pressure at the interface prevents the hydrogen from escaping.

Innovations

Producing images of the heavy titanium and the light hydrogen atoms at the interface was quite a challenge. First, the sample was loaded with hydrogen. It should subsequently be viewed in a specific orientation along the interface. This was achieved by cutting properly aligned crystals from titanium using an ion beam and making the samples thinner - to a thickness of no more than 50 nm - again using an ion beam.

The visualization of both titanium and hydrogen atoms was made possible by several innovations that were included in the TEM. Heavy atoms can be visualized by the scattering that they cause of the electrons in the microscope beam. Scattered electrons are preferably detected using high-angle detectors. 'Hydrogen is too light to cause this scattering, so for these atoms, we have to rely on constructing the image from low-angle scattering, which includes electron waves.' However, the material causes interference of these waves, which has so far made the identification of hydrogen atoms almost impossible.

Computer simulations

The waves are detected by a low-angle bright-field detector. The new microscope has a circular bright-field detector that is divided into four segments. By analyzing differences in the wavefronts detected in opposing segments and looking at the changes that occur when the scanning beam crosses the material, it is possible to filter out the interferences and visualize the very light hydrogen atoms.

'The first requirement is to have a microscope that can scan with an electron beam that is smaller than the distance between the atoms. It is subsequently the combination of the segmented bright-field detector and the analytical software that makes visualization possible,' explains Kooi, who worked in close collaboration with scientists from the microscope's manufacturer, Thermo Fisher Scientific, two of whom are co-authors on the paper. Kooi's group added various noise filters to the software and tested them. They also performed extensive computer simulations, against which they compared the experimental images.

Nanomaterials

The study shows the interaction between the hydrogen and the metal, which is useful knowledge for the study of materials capable of storing hydrogen. 'Metal hydrides can store more hydrogen per volume than liquid hydrogen.' Furthermore, the techniques used to visualize the hydrogen could also be applied to other light atoms, such as oxygen, nitrogen or boron, which are important in many nanomaterials. 'Being able to see light atoms next to heavy ones opens up all kinds of opportunities.'

T cells play a huge role in our immune system's fight against modified cells in the body that can develop into cancer. Phagocytes and B cells identify changes in these cells and activate the T cells, which then start a full-blown program of destruction. This functions well in many cases - unless the cancer cells mutate and develop a kind of camouflage that let them escape the immune system undetected. Researchers at the University of Freiburg and the Leibniz University Hannover (LUH) have now described how a key protein in this process known as "immune escape" becomes activated. The team headed by Prof. Dr. Maja Banks-Köhn and Prof. Dr. Wolfgang Schamel from the excellence clusters for biological signaling studies CIBSS and BIOSS at the University of Freiburg and the structural biologist Prof. Dr. Teresa Carlomagno from the LUH used biophysical, biochemical, and immunological methods in their research. Based on these insights, chemical biologist Banks-Köhn, hopes to develop drugs that intervene specifically in this activation mechanism. In the future, they could thereby improve established cancer treatments that rely on so-called immune checkpoint inhibitors. The team has recently published its research in a study in the scientific journal "Science Advances".

Checkpoint inhibitors are therapeutic antibodies that work by binding to the receptors of T cells. Proteins on the surface of the T cells called immune checkpoint receptors such as programmed cell death 1, or PD1, along with the signaling pathways that are triggered by them are what stop immune responses in a healthy body. This regulating mechanism prevents symptoms of inflammation from lasting too long and getting out of control. These symptoms include redness, swelling, and fever. Cancer cells take advantage of mechanisms such as these to render the body helpless while the cells multiply. Using cell cultures and interaction studies, the researchers from the two universities discovered that a signaling protein called SHP2 in T cells binds to PD1 in two specific places after it has been activated by a signal from cancer cells. It is this double binding to SHP2 that promotes the camouflaging effect and switches off the immune cells' response completely.

Antibodies that block immune inhibitors like PD1 are approved treatments for skin melanomas and lung carcinomas, and they prolong patients' lives. However, as a result, many patients suffer from autoimmune reactions. "Drugs that prevent the binding of SHP2 and PD1 could be used in the future to make side-effects less severe and to support, or to act as alternatives to, antibody treatments," says Banks-Köhn. She and Schamel studied the immune response of B cells and T cells by modifying SHP2 molecules, testing their predictions based crystal structure and magnetic resonance analysis of the team from the LUH. Their data shows precisely how and in what areas the SHP2 protein binds to PD1, thereby revealing a possible target area for drugs. "In our ongoing research project at the CIBSS - Centre for Integrative Biological Signalling Studies the next step is to decode the signaling pathway of PD1 - in other words, where the proteins are located in the cell, where they bind, and within what time frame the signals take effect," Banks-Köhn says.

Authors caution that given the lack of a robust and detailed timeline of records of suspected, probable, and confirmed cases and close contacts, the true size of the epidemic and its pandemic potential remains unclear.

New modelling research, published in The Lancet, estimates that up to 75,800 individuals in the Chinese city of Wuhan may have been infected with 2019 novel coronavirus (2019-nCoV) as of January 25, 2020.

Senior author Professor Gabriel Leung from the University of Hong Kong highlights: "Not everyone who is infected with 2019-nCoV would require or seek medical attention. During the urgent demands of a rapidly expanding epidemic of a completely new virus, especially when system capacity is getting overwhelmed, some of those infected may be undercounted in the official register." [1]

He explains: "The apparent discrepancy between our modelled estimates of 2019-nCoV infections and the actual number of confirmed cases in Wuhan could also be due to several other factors. These include that there is a time lag between infection and symptom onset, delays in infected persons coming to medical attention, and time taken to confirm cases by laboratory testing, which could all affect overall recording and reporting." [1]

The new estimates also suggest that multiple major Chinese cities might have already imported dozens of cases of 2019-nCoV infection from Wuhan, in numbers sufficient to initiate local epidemics.

The early estimates underscore that it will likely take rapid and immediate scale-up of substantial public health control measures to prevent large epidemics in areas outside Wuhan. Further analyses suggest that if transmissibility of 2019-nCoV could be reduced, both the growth rate and size of local epidemics in all cities across China could be reduced.

"If the transmissibility of 2019-nCoV is similar nationally and over time, it is possible that epidemics could be already growing in multiple major Chinese cities, with a time lag of one to two weeks behind the Wuhan outbreak," says lead author Professor Joseph Wu from the University of Hong Kong. "Large cities overseas with close transport links to China could potentially also become outbreak epicentres because of substantial spread of pre-symptomatic cases unless substantial public health interventions at both the population and personal levels are implemented immediately." [1]

According to Professor Gabriel Leung: "Based on our estimates, we would strongly urge authorities worldwide that preparedness plans and mitigation interventions should be readied for quick deployment, including securing supplies of test reagents, drugs, personal protective equipment, hospital supplies, and above all human resources, especially in cities with close ties with Wuhan and other major Chinese cities." [1]

In the study, researchers used mathematical modelling to estimate the size of the epidemic based on officially reported 2019-nCoV case data and domestic and international travel (i.e., train, air, road) data. They assumed that the serial interval estimate (the time it takes for infected individuals to infect other people) for 2019-nCoV was the same as for severe acute respiratory syndrome (SARS: table 1). The researchers also modelled potential future spread of 2019-nCoV in China and internationally, accounting for the potential impact of various public health interventions that were implemented in January 2020 including use of face masks and increased personal hygiene, and the quarantine measures introduced in Wuhan on January 23.

The researchers estimate that in the early stages of the Wuhan outbreak (from December 1, 2019 to January 25, 2020) each person infected with 2019-nCoV could have infected up to 2-3 other individuals on average, and that the epidemic doubled in size every 6.4 days. During this period, up to 75,815 individuals could have been infected in Wuhan.

Additionally, estimates suggest that cases of 2019-nCoV infection may have spread from Wuhan to multiple other major Chinese cities as of January 25, including Guangzhou (111 cases), Beijing (113), Shanghai (98), and Shenzhen (80; figure 3). Together these cities account for over half of all outbound international air travel from China.

While the estimates suggest that the quarantine in Wuhan may not have the intended effect of completely halting the epidemic, further analyses suggest that if transmissibility of 2019-nCoV could be reduced by 25% in all cities nationally with expanded control efforts, both the growth rate and size of local epidemics could be substantially reduced. Moreover, a 50% reduction in transmissibility could shift the current 2019-nCoV epidemic from one that is expanding rapidly, to one that is slowly growing (figure 4).

"It might be possible to reduce local transmissibility and contain local epidemics if substantial, even draconian, measures that limit population mobility in all affected areas are immediately considered. Precisely what and how much should be done is highly contextually specific and there is no one-size-fits-all set of prescriptive interventions that would be appropriate across all settings," says co-author Dr Kathy Leung from the University of Hong Kong. "On top of that, strategies to drastically reduce within-population contact by cancelling mass gatherings, school closures, and introducing work-from-home arrangements could contain the spread of infection so that the first imported cases, or even early local transmission, does not result in large epidemics outside Wuhan." [1]

The authors point to several limitations of their study, including that the accuracy of their estimates depend on their assumption about the zoonotic source of infection in Wuhan. They also highlight that the models assume travel behaviour was not affected by disease status and that all infections eventually have symptoms--so it is possible that milder cases have gone undetected which could underestimate the size of the outbreak. Lastly, they note that their epidemic forecast was based on inter-city mobility data from 2019, and might not reflect mobility patterns in 2020, particularly in light of the health threat posed by 2019-nCoV.

Theoretical physicists from Trinity College Dublin have found a deep link between one of the most striking features of quantum mechanics - quantum entanglement - and thermalisation, which is the process in which something comes into thermal equilibrium with its surroundings.

Their results are published today [Friday 31st January 2020] in the prestigious journal Physical Review Letters.

We are all familiar with thermalisation - just think how your coffee reaches room temperature over time. Quantum entanglement on the other hand is a different story.

Yet work performed by Marlon Brenes, PhD Candidate, and Professor John Goold from Trinity, in collaboration with Silvia Pappalardi and Professor Alessandro Silva at SISSA in Italy, shows how the two are inextricably linked.

Explaining the importance of the discovery, Professor Goold, leader of Trinity's QuSys group, explains:

"Quantum entanglement is a counterintuitive feature of quantum mechanics, which allows particles that have interacted with each other at some point in time to become correlated in a way which is not possible classically. Measurements on one particle affect the outcomes of measurements of the other-- even if they are light years apart. Einstein called this effect 'spooky action at a distance'."

"It turns out that entanglement is not just spooky but actually ubiquitous and in fact what is even more amazing is that we live in an age where technology is starting to exploit this feature to perform feats which were thought to be impossible just a number of years go. These quantum technologies are being developed rapidly in the private sector with companies such as Google and IBM leading the race."

But what has all this got to do with cold coffee?

Professor Goold elaborates:

"When you prepare a cup of coffee and leave it for a while it will cool down until it reaches the temperature of its surroundings. This is thermalisation. In physics we say that the process is irreversible - as we know, our once-warm coffee won't cool down and then magically warm back up. How irreversibility and thermal behaviour emerges in physical systems is something which fascinates me as a scientist as it applies on scales as small as atoms, to cups of coffee, and even to the evolution of the universe itself. In physics, statistical mechanics is the theory which aims at understanding this process from a microscopic perspective. For quantum systems the emergence of thermalisation is notoriously tricky and is a central focus of this current research."

So what's all this got to do with entanglement and what do your results say?

"In statistical mechanics there are various different ways, known as ensembles, in which you can describe how a system thermalizes, all of which are believed to be equivalent when you have a large system (roughly on scales of 10^23 atoms). However, what we show in our work is that not only is entanglement present in the process, but its structure is very different depending on which way you choose to describe your system. So, it gives us a way to test foundational questions in statistical mechanics. The idea is general and can be applied to a range of systems as small as a few atoms and as large as blackholes."

Marlon Brenes, PhD candidate at Trinity and first author of the paper, used super-computers to simulate quantum systems to test the idea.

Brenes, a numerical specialist, said:

"The numerical simulations for this project that I performed are at the limit of what can currently be done at the level of high-performance computing. To run the code I used the national facility, ICHEC, and the new Kay machine there. So, as well as being a nice fundamental result the work helped us really push the boundaries of this type of computational approach and establish that our codes and the national architecture are performing at the cutting edge."

The Journal of Developmental & Behavioral Pediatrics is releasing a groundbreaking guideline for the diagnosis and care of attention-deficit/hyperactivity disorders in children and youth in a supplement to its February 2020 issue.

The Society for Developmental and Behavior Pediatrics Clinical Practice Guideline for the Assessment and Treatment of Children and Adolescents with Complex ADHD (SDBP Complex ADHD Guideline) provides recommendations for the evaluation and treatment of ADHD in youths that is rooted in an understanding of how the disorder affects function in children across behavioral, social and academic settings, as well as how it impacts adolescence and adulthood for most patients.

While ADHD is highly prevalent in the United States, advancements in its assessment and treatment have not mirrored those of other serious, chronic childhood illnesses. For many children, ADHD is persistent in adulthood and can lead to coexisting psychiatric disorders. The SDBP guideline aims to provide a framework for a more systematic approach to diagnosing and treating children with complex ADHD.

Physicists at Washington University in St. Louis have proposed a way to use data from ultra-high energy neutrinos to study interactions beyond the standard model of particle physics. The 'Zee burst' model leverages new data from large neutrino telescopes such as the IceCube Neutrino Observatory in Antarctica and its future extensions.

"Neutrinos continue to intrigue us and stretch our imagination. These 'ghost particles' are the least understood in the standard model, but they hold the key to what lies beyond," said Bhupal Dev, assistant professor of physics in Arts & Sciences and author of a new study in Physical Review Letters.

"So far, all nonstandard interaction studies at IceCube have focused only on the low-energy atmospheric neutrino data," said Dev, who is part of Washington University's McDonnell Center for the Space Sciences. "The 'Zee burst' mechanism provides a new tool to probe nonstandard interactions using the ultra-high energy neutrinos at IceCube."

Ultra-high energy events

Since the discovery of neutrino oscillations two decades ago, which earned the 2015 Nobel Prize in physics, scientists have made significant progress in understanding neutrino properties -- but a lot of questions remain unanswered.

For example, the fact that neutrinos have such a tiny mass already requires scientists to consider theories beyond the standard model. In such theories, "neutrinos could have new nonstandard interactions with matter as they propagate through it, which will crucially affect their future precision measurements," Dev said.

In 2012, the IceCube collaboration reported the first observation of ultra-high energy neutrinos from extraterrestrial sources, which opened a new window to study neutrino properties at the highest possible energies. Since that discovery, IceCube has reported about 100 such ultra-high energy neutrino events.

"We immediately realized that this could give us a new way to look for exotic particles, like supersymmetric partners and heavy decaying dark matter," Dev said. For the previous several years, he had been looking for ways to find signals of new physics at different energy scales and had co-authored half a dozen papers studying the possibilities.

"The common strategy I followed in all these works was to look for anomalous features in the observed event spectrum, which could then be interpreted as a possible sign of new physics," he said.

The most spectacular feature would be a resonance: what physicists witness as a dramatic enhancement of events in a narrow energy window. Dev devoted his time to thinking about new scenarios that could give rise to such a resonance feature. That's where the idea for the current work came from.

In the standard model, ultra-high energy neutrinos can produce a W-boson at resonance. This process, known as the Glashow resonance, has already been seen at IceCube, according to preliminary results presented at the Neutrino 2018 conference.

"We propose that similar resonance features can be induced due to new light, charged particles, which provides a new way to probe nonstandard neutrino interactions," Dev said.

Bursting onto the neutrino scene

Dev and his co-author Kaladi Babu at Oklahoma State University considered the Zee model, a popular model of radiative neutrino mass generation, as a prototype for their study. This model allows for charged scalars to be as light as 100 times the proton mass.

"These light, charged Zee-scalars could give rise to a Glashow-like resonance feature in the ultra-high energy neutrino event spectrum at the IceCube Neutrino Observatory," Dev said.

Because the new resonance involves charged scalars in the Zee model, they decided to call it the 'Zee burst.'

Yicong Sui at Washington University and Sudip Jana at Oklahoma State, both graduate students in physics and co-authors of this study, did extensive event simulations and data analysis showing that it is possible to detect such a new resonance using IceCube data.

"We need an effective exposure time of at least four times the current exposure to be sensitive enough to detect the new resonance -- so that would be about 30 years with the current IceCube design, but only three years of IceCube-Gen 2," Dev said, referring to the proposed next-generation extension of IceCube with 10 km3 detector volume.

"This is an effective way to look for the new charged scalars at IceCube, complementary to direct searches for these particles at the Large Hadron Collider."

In the face of a changing climate, the process of accounting greenhouse gas emissions is becoming ever more critical. Governments around the world are striving to hit reduction targets using Intergovernmental Panel on Climate Change (IPCC) guidelines to limit global warming. To have a chance of hitting these targets, they need to know how to accurately calculate and report emissions and removals.

The IPCC guidelines are essential but woefully out of date, say researchers from the Yale School of Forestry & Environmental Studies (F&ES), and in need of improvement as countries prepare inventory reports as part of Paris Agreement commitments over the next year.

"Global society could be doing a better job in producing greenhouse gas inventories," said Leehi Yona '18 M.E.Sc., the lead author of a paper recently published in the academic journal Ambio. "It is paramount that we get greenhouse gas inventories right, so that the emissions we report are equal to the emissions in the atmosphere. Closing this gap between actual and reported emissions is a prerequisite to successful climate change mitigation."

Yona was joined on the paper by Mark Bradford, professor of soils and ecosystem ecology at F&ES, and former F&ES faculty member Ben Cashore.

In the paper, the researchers outline the limitations of the current IPCC guidelines. Firstly, the process through which the guidelines are produced has not been updated since their inception in 1996. The guidelines currently require a cumbersome, multi-step review process where government-nominated experts write and revise drafted reports. Aside from the fact the experts are then not independent of national interests, the guidelines fail to take advantage of the tremendous advances made in "synthesis approaches" that can more accurately and expeditiously be used to inventory national-level greenhouse gas emissions.

The methodology for reporting greenhouse gas emissions presents another challenge. A multi-tiered system of methodologies was initially created by the IPCC to properly address the economic statuses of the different signatory countries involved in the agreement. Larger, wealthier countries were expected to apply more rigorous methodologies, while developing nations used the default methods of reporting. However, nearly all of the nations are still using the default methods in part due to a lack of resources.

It is these default methods then that the researchers say must be improved. Though challenges exist, the researchers lay out technological advances that can properly address them. They suggest such things as using satellite imagery to fill data gaps coupled with machine-learning tools that expedite quantitative synthesis, as well as account for emissions associated with land use and management. They also recommend a dynamic and transparent review process modeled after "the Cochrane Collaboration," used in medicine and health science to expertly synthesize the most recent scientific data to inform medical policy and practice that directly benefits the public.

"Evidence synthesis has revolutionized in the past 25 years, since the first greenhouse gas inventories were developed," said Bradford. "Medicine has availed of these advances, providing relevant, up-to-date, high-quality information to save and improve the quality of millions of lives. Our planetary health surely demands that we use such advances in synthesis to similarly inform the accounting and management of greenhouse gas emissions."