Earth

The giant impacts that dominate late stages of planet formation have a wide range of consequences for young planets and their atmospheres, according to new research.

Research led by Durham University and involving the University of Glasgow, both UK, has developed a way of revealing the scale of atmosphere loss during planetary collisions based on 3D supercomputer simulations.

The simulations show how Earth-like planets with thin atmospheres might have evolved in an early solar system depending on how they are impacted by other objects.

Using the COSMA supercomputer, part of the DiRAC High-Performance Computing facility in Durham, funded by the Science and Technology Facilities Council (STFC), the researchers ran more than 100 detailed simulations of different giant impacts on Earth-like planets, altering the speed and angle of the impact on each occasion.

They found that grazing impacts - like the one thought to have formed our Moon - led to much less atmospheric loss than a direct hit.

Head on collisions and higher speeds led to much greater erosion, sometimes obliterating the atmosphere completely along with some of the mantle, the layer that sits under a planet's crust.

The findings provide greater insight into what happens during these giant impacts, which scientists know are common and important events in the evolution of planets both in our solar system and beyond.

The findings are published in the Astrophysical Journal.

Our Moon is believed to have formed about 4.5 billion years ago following a collision between the early Earth and a giant impactor possibly the size of Mars.

It was not known how much of the Earth's early atmosphere could have survived in this violent impact event, or how this would change for different collision scenarios.

In the Earth's case, the planet got relatively lucky with this collision - only losing between ten and 50 per cent of its atmosphere depending on the precise scenario.

Lead author Dr Jacob Kegerreis, whose research was part-funded by a doctoral scholarship from the STFC, in the Institute for Computational Cosmology, at Durham University, said: "We know that planetary collisions can have a dramatic effect on a planet's atmosphere, but this is the first time we've been able to study the wide varieties of these violent events in detail.

"In spite of the remarkably diverse consequences that can come from different impact angles and speeds, we've found a simple way to predict how much atmosphere would be lost.

"This lays the groundwork to be able to predict the atmospheric erosion from any giant impact, which would feed in to models of planet formation as a whole. This in turn will help us to understand both the Earth's history as a habitable planet and the evolution of exoplanets around other stars."

The researchers are now carrying out hundreds more simulations to test the effects that the different masses and compositions of colliding objects might have.

Co-author Dr Vincent Eke, in the Institute for Computational Cosmology, Durham University, said: "At the moment it appears that the amount of atmosphere a planet loses due to these collisions depends upon how lucky or unlucky they are in terms the type of the impact they suffer."

Fellow co-author Dr Luis Teodoro, of the University of Glasgow, said: "Our research shows how different impacts can eject anywhere from very little to all of an atmosphere through a variety of mechanisms."

A new radiotracer, 18F-SynVesT-2, can directly assess synaptic density changes in the brain, providing an objective and quantitative measure of disease progression after stroke. Research presented at the Society of Nuclear Medicine and Molecular Imaging 2020 Annual Meeting shows that the radiotracer may also offer a primary endpoint to evaluate treatment efficacy of novel therapeutics for stroke in clinical trials.

Current positron emission tomography (PET) imaging of stroke focuses on the measurement of oxygen or glucose metabolism. 18F-FDG PET has been used to probe brain tissue viability after acute ischemic stroke, but transient hyperglycemia, a common phenomenon in acute stroke patients, affects FDG uptake and thereby confounds its interpretation. "Because synapse is a crucial microstructure for brain functions and synaptic deficit is a hallmark of stroke, we developed a new imaging method to assess synapses directly, providing an alternative to measuring metabolism to determine stroke progression," said Xueying Lyu, postgraduate research associate at Yale University School of Medicine in New Haven, Connecticut.

Researchers utilized a rat model of stroke (established through a middle cerebral artery occlusion procedure followed by reperfusion) to test the 18F-SynVesT-2 radiotracer. A total of six stroke model rats underwent weekly 18F-SynVesT-2 PET scans for four weeks, starting at one day post-reperfusion. Image analysis was conducted and standardized uptake values (SUV) were generated for the hippocampus, cerebellum, neocortex and thalamus. The SUVs of affected and non-affected sides of the brain were compared by calculating ipsi- to contralateral ratios, and the volume of lesion was assessed using SUV ratio normalized by the cerebellum, after smoothing, masking, subtracting, thresholding and binarizing.

18F-SynVesT-2 PET imaging successfully detected synapse loss in the rat model of stroke and tracked disease progression via lesion quantification. Synapse loss occurred mainly in the hippocampus, thalamus and neocortex rather than the cerebellum. The most significant loss of synapses was observed to occur during the first week post-reperfusion.

"This is the first direct demonstration of synaptic changes following stroke and has shown that the synaptic protein SV2A is a potential biomarker for tissue viability," noted Lyu. "Information on tissue viability is valuable to detect stroke early and to evaluate therapeutic efficacy and recovery. We hope to help stroke patients by bringing this SV2A PET imaging method to clinical settings in the near future."

According to the Centers for Disease Control and Prevention, more than 175,000 strokes occur each year in the United States, killing 140,000 Americans. It is a leading cause of long-term disability and costs the U.S. healthcare system an estimated $34 billion annually in health care services, treatment and lost time at work.

Biochemists at Martin Luther University Halle-Wittenberg (MLU) have used a standard electron cryo-microscope to achieve surprisingly good images that are on par with those taken by far more sophisticated equipment. They have succeeded in determining the structure of ferritin almost at the atomic level. Their results were published in the journal PLOS ONE.

Electron cryo-microscopy has become increasingly important in recent years, especially in shedding light on protein structures. The developers of the new technology were awarded the Nobel Prize for Chemistry in 2017. The trick: the samples are flash frozen and then bombarded with electrons. In the case of traditional electron microscopy, all of the water is first extracted from the sample. This is necessary because the investigation takes place in a vacuum, which means water would evaporate immediately and make imaging impossible. However, because water molecules play such an important role in biomolecules, especially in proteins, they cannot be examined using traditional electron microscopy. Proteins are among the most important building blocks of cells and perform a variety of tasks. In-depth knowledge of their structure is necessary in order to understand how they work.

The research group led by Dr Panagiotis Kastritis, who is a group leader at the Centre for Innovation Competence HALOmem and a junior professor at the Institute of Biochemistry and Biotechnology at MLU, acquired a state-of-the-art electron cryo-microscope in 2019. "There is no other microscope like it in Halle," says Kastritis. The new "Thermo Fisher Glacios 200 kV", financed by the Federal Ministry of Education and Research, is not the best and most expensive microscope of its kind. Nevertheless, Kastritis and his colleagues succeeded in determining the structure of the iron storage protein apoferritin down to 2.7 ångströms (Å), in other words, almost down to the individual atom. One ångström equals one-tenth of a nanometre. This puts the research group in a similar league to departments with far more expensive equipment. Apoferritin is often used as a reference protein to determine the performance levels of corresponding microscopes. Just recently, two research groups broke a new record with a resolution of about 1.2 Å. "Such values can only be achieved using very powerful instruments, which only a handful of research groups around the world have at their disposal. Our method is designed for microscopes found in many laboratories," explains Kastritis.

Electron cryo-microscopes are very complex devices. "Even tiny misalignments can render the images useless," says Kastritis. It is important to programme them correctly and Halle has the technical expertise to do this. But the analysis that is conducted after the data has been collected is just as important. "The microscope produces several thousand images," explains Kastritis. Image processing programmes are used to create a 3D structure of the molecule. In cooperation with Professor Milton T. Stubbs from the Institute of Biochemistry and Biotechnology at MLU, the researchers have developed a new method to create a high-resolution model of a protein. Stubbs' research group uses X-ray crystallography, another technique for determining the structure of proteins, which requires the proteins to be crystallised. They were able to combine a modified form of an image analysis technique with the images taken with the electron cryo-microscope. This made charge states and individual water molecules visible.

"It's an attractive method," says Kastritis. Instead of needing very expensive microscopes, a lot of computing capacity is required, which MLU has. Now, in addition to using X-ray crystallography, electron cryo-microscopy can be used to produce images of proteins - especially those that are difficult to crystallise. This enables collaboration, both inside and outside the university, on the structural analysis of samples with medical and biotechnological potential.

Researchers from the Peter the Great St.Petersburg Polytechnic University (SPbPU) discovered and theoretically explained a new physical effect: amplitude of mechanical vibrations can grow without external influence. Besides, the scientific group offered their explanation on how to eliminate the Fermi-Pasta-Ulam-Tsingou paradox.

The scientists of SPbPU explained it using a simple example: to rock the swing, you have to keep pushing it. It is generally believed that it is impossible to achieve oscillatory resonance without constant external influence.

However, the scientific group of the Higher School of Theoretical Mechanics, Institute of Applied Mathematics and Mechanics SPbPU discovered a new physical phenomenon of "ballistic resonance", where mechanical oscillations can be excited only due to internal thermal resources of the system.

The experimental work of researchers from all around the world demonstrated, that the heat spreads at abnormally high speeds at nano and micro levels in ultrapure crystalline materials. This phenomenon was called ballistic heat conductivity.

The scientific group supervised the corresponding member of Russian Academy of Sciences Anton Krivtsov, derived the equations describing this phenomenon and made significant progress in the overall understanding of thermal processes at the micro-level. In the study published in Physical Review E researchers considered the system behavior at the initial periodic distribution of temperature in the crystal material.

The discovered phenomenon describes that the process of heat equilibration leads to mechanical vibrations with an amplitude that grows with time. The effect is called ballistic resonance.

"Over the past few years, our scientific group has been looking into the mechanisms of heat propagation at the micro and nano levels. We found out that at these levels, the heat doesn't spread in the way we expected it to: for example, the heat can flow from cold to hot. This behavior of nanosystems leads to new physical effects, such as ballistic resonance", said Associate Professor of the Higher School of Theoretical Mechanics SPbPU Vitaly Kuzkin.

According to him, in the future, the researhers plan to analyze how this can be used in such promising materials as, for example, graphene.

These discoveries also provide an opportunity to resolve the paradox of Fermi Pasta-Ulam-Tsingou. In 1953, a scientific group led by Enrico Fermi carried out a computer experiment that later became famous. Scientists considered the simplest model of oscillations of a chain of particles connected by springs. They assumed that the mechanical movement would gradually fade away, turning into chaotic thermal oscillations. Still, the result was unexpected: the oscillations in the chain first almost decayed, but then revived and reached nearly the initial level. The system came to its initial state, and the cycle repeated itself. The causes of mechanical oscillations from thermal vibrations in the considered system have been the subject of scientific research and disputes for decades.

The amplitude of mechanical vibrations caused by ballistic resonance doesn't increase infinitely, but reaches its maximum, after that it starts gradually decreasing to zero. Eventually, the mechanical oscillations fade completely, and the temperature equilibrates in the whole crystal. This process is called thermalization. For mechanicians and physicists, this experiment is vital because a chain of particles connected by springs is a good model of crystal material.

Researchers of the Higher School of Theoretical Mechanics showed that the transition of mechanical energy into heat is irreversible if we consider the process at the finite temperature.

"Usually, it is not taken into account that in the real materials, there is a thermal motion, along with the mechanical one, and the energy of thermal motion is several orders of magnitude higher. We recreated these conditions in a computer experiment and showed that it is the thermal motion that damps the mechanical wave and prevents the revival of oscillations," explained Anton Krivtsov, director of the Higher School of Theoretical Mechanics SPbPU, corresponding member of Russian Academy of Sciences.

According to experts, the theoretical approach proposed by scientists of SPbPU demonstrates a new approach to how we understand the heat and temperature. It may be fundamental in the development of nanoelectronic devices in the future.

An offhand remark by an acquaintance about using a smartphone. A joke about someone losing their memory or hearing. An ad in a magazine focused on erasing wrinkles or gray hair. An inner worry that getting older means growing lonely.

All of these kinds of everyday ageism, and many more, are common in the lives of Americans over 50, a new poll finds. In fact, more than 80% of those polled say they commonly experience at least one form of ageism in their day-to-day lives.

The poll even shows relationships between experiencing multiple forms of everyday ageism and health. In all, 40% of all poll respondents said they routinely experience three or more forms of ageism - and these older adults were much more likely to have poor mental and physical health.

But despite all this, the poll also suggests that most older adults hold positive attitudes toward aging - including 88% who say that they have become more comfortable being themselves, and 80% who have a strong sense of purpose. Two-thirds said life over 50 is better than they thought it would be.

The new results come from the National Poll on Healthy Aging, carried out by the University of Michigan Institute for Healthcare Policy and Innovation with support from AARP and Michigan Medicine, U-M's academic medical center. It involved a national sample of more than 2,000 adults aged 50 to 80.

The poll was taken in December, before the COVID-19 pandemic arrived and introduced new health risks for older adults. But the researchers hope the findings will inform efforts to address assumptions about older adults' thoughts and experiences, and any age-based discrimination and negative consequences on health and well-being that may arise because of of the pandemic.

"Everyday ageism is part of American culture and one of the most common and socially condoned forms of prejudice and discrimination. There is no doubt that it harms the health and wellbeing of older adults, yet we don't have enough data on how older adults experience it and how harmful it is," says Julie Ober Allen, Ph.D., a research fellow at the U-M Institute for Social Research who partnered with the poll team to develop the questions and analyze the results.

"In addition to addressing everyday ageism in general, we as a society should be especially careful about how ageist prejudices and stereotypes affect our response to the massive public health challenges of the ongoing pandemic."

Confronting stereotypes

The new poll asked older adults about nine forms of everyday ageism, and analyzed the results based on respondents' age, income, media consumption habits, residence, work status and self-reported health and appearance.

In all, 65% said they're commonly exposed to ageist messages in materials they watch or read, and 45% said they sometimes or often experience ageism in interactions with other people. More than one-third of older adults have internalized stereotypes to the extent that they agreed or strongly agreed that feeling lonely or depressed were inherent parts of growing older.

Older and lower income older adults were more likely to report that they commonly experienced three or more forms of everyday ageism. Women, those who had retired and those who lived in rural areas were also more likely than men to experience it, as well as those still working and those living in suburban or urban areas.

Those who spent more time watching television, browsing the internet or reading magazines were also more likely to report that they'd been exposed to more different forms of ageism than those who spent less time consuming media.

The relationship between ageism experiences in older adults' day-to-day lives and health especially interested poll director Preeti Malani, M.D., a professor at Michigan Medicine with a background in caring for older adults.

"The fact that our poll respondents who said they'd felt the most forms of ageism were also more likely to say their physical or mental health was fair or poor, or to have a chronic condition such as diabetes or heart disease, is something that needs more examination," she says. "On the other hand, the fact that half of our respondents agreed with all four of the positive views on aging that we asked them about is encouraging."

Dispelling ageism

AARP has focused attention on the effects of ageism in the workplace, and worked to dispel outdated perceptions of aging.

"As Americans continue living longer, society must redefine what it means to get older,"says Alison Bryant, Ph.D., senior vice president of research for AARP. "We are encouraged these findings show most older adults feel positive about their lives, reaffirming that we can be active and happy in older age, but we have more work to do to disrupt damaging negative associations around aging."

For drugs to be effective, they usually have to dock to proteins in the organism. Like a key in a lock, part of the drug molecule must fit into recesses or cavities of the target protein. For several years now, the team of the Macromolecular Crystallography Department (MX) at HZB headed by Dr. Manfred Weiss together with the Drug Design Group headed by Prof. Gerhard Klebe (University of Marburg) has therefore been working on building up what are known as fragment libraries. These consist of small organic molecules (fragments) with which the functionally important cavities on the surface of proteins can be probed and mapped. Protein crystals are saturated with the fragments and then analysed using powerful X-ray light. This allows three-dimensional structural information to be obtained at levels of atomic resolution. Among other things, it is possible to find out how well a specific molecule fragment docks to the target protein. The development of these substance libraries took place as part of the joint Frag4Lead research project and was funded by the German Federal Ministry of Education and Research (BMBF).

The MX team (MX stands for Macromolecular Crystallography) has now published the design of a chemically diverse fragment library called the "F2X-Universal" library, which consists of 1,103 compounds. A representative selection of 96 compounds has been extracted from this library, which is referred to as the F2X Entry Screen. In the course of publishing the library, this selection has now been successfully tested and validated by the MX team of the HZB at the MAX IV X-ray source in Lund, Sweden and at BESSY II.

In the study, the HZB and MAX IV teams verified the efficiency of the F2X Entry library by screening endothiapepsin and the Aar2/RnaseH protein complex as the target enzymes. In the next step, the MX team will use the entire universal library.

"For the current study, the fragment screening experts at HZB - BESSY II worked very closely with the FragMAX project team at MAX IV", said Dr. Uwe Müller from the MX team at HZB who helped to set up the three MX beamlines at BESSY II as well as the BioMAX beamline at MAX IV. "This enabled both partners to further develop their own technology platforms and use them for imaging the functional surfaces of different proteins. This will be an excellent basis for future collaboration between MAX IV and HZB."

Antibiotic resistance is a growing challenge in the treatment of infectious diseases worldwide. Bacteria become resistant to antibiotics by acquiring or mutating genes that allow them to survive the administration of antibiotics, which otherwise would kill them. However, this advantage in the presence of antibiotics can imply costs to bacteria when the drugs stop being administered. This occurs because resistance generally affects genes that are essential for the cell and so, once back to the original context, without antibiotics, bacteria stop being fit to compete for its own survival.

Until now, our knowledge about this process comes from studies done in artificial systems that provide an incomplete perspective on the real complexity of this phenomenon. To bridge this gap, a team of researchers led by Isabel Gordo, principal investigator at IGC, used mice as a model organism and identified that in the gut, after the administration of antibiotics, competition for survival shows very different dynamics over time depending on the host where it occurs. The same resistance has different interactions that determine that in one individual a bacterium has low ability to survive in the absence of antibiotics, whereas in another individual that ability is high.

Using the bacteria Escherichia coli, researchers have found that the differences in the cost of carrying resistance for a bacterium are due to the differences in the intestinal flora (or microbiota) of each host. "We have observed that mice without microbiota show no differences in the survival dynamics of resistant bacteria, that always suffer damage and are unable to survive", explains Isabel Gordo. On the contrary, mice with diverse intestinal flora reported a "great variability in the dynamics of survival of resistant bacteria, which are specific of each host, thus establishing a causal relation between individual microbiota and the survival of antibiotic resistant bacteria" says Isabel.

To further understand these results they used a mathematical model that simulates how individual properties of the microbiota can explain different costs of antibiotic resistance in each individual. Besides explaining the effect previously observed in the mouse gut, the model predicts that "over time and as the microbiota stabilizes after the administration of antibiotics, resistance should disappear is all hosts, unless the bacteria compensate for the negative effects caused by the gain of resistance itself. The predictions reveal that even the acquisition of compensation mechanisms depends on the microbiota composition of each individual" clarifies Massimo Amicone, co-author of the study.

These results were later confirmed experimentally in mice, highlighting "the highly personalized features of how survival and maintenance of antibiotic-resistant bacteria can occur in each one of us", say Luís Cardoso and Paulo Durão, also co-authors of the study.

Future steps include "finding the Achilles heel of resistant bacteria in the gut, a research line that we are developing in several angles" explains Isabel Gordo. "At least one of our hypotheses is providing great results: even when colonizing the gut in the least favorable conditions we are being able to eliminate them faster!" reveals Isabel enthusiastically.

The COVID-19 pandemic presents an opportunity to transform food systems and achieve sustainable development. But the lively policy debate on which policy approach will promote agricultural development in Africa still prevents progress.

Debates include: Do small-scale farms have development potential or does supporting them promote 'romantic populism'? Are input subsidy programs an effective strategy to increase agricultural productivity? What role should the government play?

In new research published in World Development, economists argue that a dichotomy between either state-led or market-led approaches to boost food production leads to political deadlock that hinders alternative solutions.

State-led or market-led policy to boost agriculture?

State-led oriented approaches tend to favor incentives, such as fertilizer subsidy programs for increasing agricultural productivity. Market-led approaches favor competitive approaches led by the private sector.

Using policy-making in Senegal as a case study, authors say empirical analysis of economic incentives like subsidy programs for fertilizer, and critiques of such incentives, must be complemented by an analysis of narratives that unravel the policy ideas of decision-makers.

Both sides must be more open to alternative solutions not only based on already-existing evidence, but also through analysis of one-sided 'stories' that reveal why specific policies are favored, say the authors.

"To really bring change, we need new frameworks and additional methods," said Jonathan Mockshell, an Agricultural Economist at the Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT).

Forging a way forward

"We shouldn't look at numbers only. We need to understand underlying narratives behind the numbers, to study how the use of language influences policy-making. When decision-makers speak, they use persuasive narratives to convey policy positions. Missing such narratives in the policy process and program design is like missing gold in the soil."

"Amid persistent low agricultural productivity across Africa, cracks in our food systems, locust outbreaks and the global COVID-19 pandemic, it's not really about who is right or wrong," said Mockshell.

"It is about finding a better narrative for what works where. The time for achieving the Sustainable Development Goals (SDGs) is too short for this continued dichotomy. We need to bridge the two narratives now to achieve sustained agricultural development."

Market-smart solutions

Regina Birner, Professor at the University of Hohenheim, said: "The actors in favor of state-led agricultural support do have 'a better story' as far as the structure of their narrative is concerned. This does, however, not imply that their story is better in a normative sense.

"Or that their prescribed policies are indeed better suited to reach their intended goals than the policies suggested by the authors who favor market-led agricultural support. The actors who favor state-led support have a dominant narrative influenced by what they think is needed to transform the agricultural sector."

"The counter narrative is that input-subsidies won't work and crowd out private sector investment. Alternative narratives offer a way forward. An existing example, though not well developed, is "market-smart subsidies".
They are defined as temporary subsidies designed to promote rather than undermine the development of fertilizer markets, for example, by using fertilizer vouchers.

A combination of such state-led initiatives, combined with donor-funded or market-led approaches and input subsidy programs can work, if there is evidence-based policy learning between both camps to better-align policy with reality, say the authors.

The world can expect more rainfall as the climate changes, but it can also expect more water to evaporate, complicating efforts to manage reservoirs and irrigate crops in a growing world, according to a Clemson University researcher whose latest work has been published in the journal Nature Communications.

Ashok Mishra, who is the corresponding author on the new article, said that previous studies have focused mostly on how climate change will affect precipitation. But the key contribution of the new study is that it also examined the magnitude and variability of precipitation and evaporation and how much water will be available during the wettest and driest months of the year.

Researchers found that dry seasons will become drier, and wet seasons will become wetter, said Mishra, who is the Dean's Associate Professor in the Glenn Department of Civil Engineering.

Most of the Eastern United States, including all of South Carolina, has high precipitation that it is well distributed throughout the year, researchers found. The region and others like it can expect greater precipitation and evaporation in both wet and dry seasons, according to the study. The amount of water available will vary more widely than it does now, researchers found.

The greatest concern for such regions will be more flooding, Mishra said in an interview.

The regions that will be hardest hit by climate change are the ones that already get slammed with rain during wet seasons and struggle with drought during dry seasons, researchers found. They include much of India and its neighbors to the east, including Bangladesh and Myanmar, along with an inland swath of Brazil, two sections running east-west across Africa, and northern Australia, according to the study.

"The regions which already have more drought and flooding relative to other regions will further see an increase in these events," Mishra said.

As part of the study, researchers divided the world into nine land regions, or regimes. They looked at annual precipitation and how it fluctuates through the seasons for each region from 1971-2000.

Researchers then used that data to predict future water availability during each region's three wettest months and three driest months. They evaluated three scenarios based on multiple global climate models.

The best case scenario for relatively stable water availability during wet and dry seasons is that the global temperature will stabilize at 2 degrees Celsius over pre-industrial levels, according to the study.

But researchers also looked at what would happen if the temperature were to rise to 3.5 degrees Celsius or 5 degrees Celsius over pre-industrial levels by the end of the century.

The higher the temperature, the more variation in water availability, researchers found.

Mishra said that his message to the world is that water is a very important resource.

"The availability of this resource is an issue everybody is facing," he said. "We need to take precautions to optimally use how much water we have. As the climate changes and population increases, we should be preparing for the future by improving the technology to efficiently use water for crops."

Jesus M. de la Garza, chair of the Glenn Department of Civil Engineering, congratulated Mishra on publication of the research.

"Dr. Mishra and his team have taken a novel approach to examining climate change," de la Garza said. "Their work is a step toward developing sustainable solutions ensuring the world has an adequate water supply. With this new article, Dr. Mishra is helping raise Clemson University's global reputation for high-quality research."

A portable testing lab that fits into a suitcase is being hailed as the key to tackling one of the world's biggest dangers to health.

Experts from Newcastle University UK, have been working with the Addis Ababa Water and Sewerage Authority (AAWSA), Addis Ababa University (AAU) and the International Water Management Institute (IWMI) to ensure waterborne hazards can be identified in a quicker, easier and ultimately cheaper way, anywhere in the world.

Using smaller and less expensive versions of the same type of specialist equipment found in state-of-the-art microbiology laboratories in the UK, the new suitcase lab - believed to be a world first - enables screening of millions of bacteria in a single water sample, instead of running many tests in parallel to look for different pathogens.

Genetic analysis can bring to light numerous hazards potentially present in water, but such analysis is currently carried out in a laboratory, using large and expensive machines. These facilities are often not available in developing countries, and the process of sending samples from the affected country to the UK for detailed analysis can take more than a month.

The portable lab means scientists can go direct to the location where a waterborne disease is thought to be present and screen a water sample for genetic material - with results available within a day or two.

The data can be used for measuring the effectiveness of wastewater treatment, faecal pollution source tracking and the identification of waterborne hazards in surface and groundwater. The rapid data generation gives public health officials more opportunity to quickly identify and deal with local hazards, potentially saving countless lives.

After initial on-site testing on samples collected at Birtley sewage treatment plant in North East England, the suitcase lab was used to carry out water quality screening in the Akaki River catchment near Addis Ababa, Ethiopia. These achievements have just been published in the journal Water Research.

Dr David Werner, Professor in Environmental Systems Modelling, Newcastle University, explains: "By taking advantage of innovative technologies to make it easier and faster to carry out on-site water quality assessments, and with our Ethiopian colleagues, we have demonstrated a way to study genetic material with affordable resources almost anywhere in the world.

"With our portable laboratory we successfully screened millions of bacteria in Akaki River water samples and discovered a high prevalence of Arcobacter butzleri, a still poorly understood waterborne hazard that can cause watery diarrhoea. Unfortunately, diarrhoea is still a leading cause of death among children under the age of five."

Government advice to "wash your hands frequently" exemplifies the importance of safe water and sanitation for hygiene and public health. But according to the United Nations, six in 10 people lack access to safely managed sanitation facilities and three in 10 people in the world lack access to safely managed drinking water services.

As well as reducing the time required to measure water quality, the project aims to enable the independent use of the tools by researchers and water systems engineers in Ethiopia. Dr Alemseged Tamiru Haile from the IWMI is confident that the scientific break-through will make a difference in Ethiopia.

"Our collaboration with Newcastle University in terms of carrying out the field work and analysis provided an opportunity for the hands-on training of 13 junior experts in Ethiopia at AAWSA facilities," he says. "One AAWSA staff member then visited Newcastle to receive intensive training in water quality monitoring with the portable laboratory. Academics from AAU can now integrate the novel approach into their curriculum. The equipment items we have assembled in the portable laboratory are affordable for AAU and AAWSA."

AAWSA is constructing more sewage treatment plants in Addis Ababa, and the team will continue their monitoring in the Akaki catchment to provide evidence for the benefits of these investments in public health.

Dr Kishor Acharya is the early career scientist at Newcastle University who has led the development of the portable molecular toolbox. He has delivered training workshops in portable metagenomics to junior academics and laboratory technicians from research institutions, NGOs, and government agencies in Tanzania, Thailand, Malaysia, Nepal, India and Ethiopia.

Dr Acharya, who is originally from Nepal, says that the portable lab kit could easily be used in many different contexts to screen for dangerous pathogens. "I want to demonstrate the applicability of the mobile toolkit and the protocols we've developed for microbial hazard surveying to other disciplines," he explains. "In the future, this kit could potentially be used as a way to assure food and drink safety, efficient health services, productive agriculture and beyond."

Is middle age really the "golden age" when people are the most optimistic in life? Researchers from Michigan State University led the largest study of its kind to determine how optimistic people are in life and when, as well as how major life events affect how optimistic they are about the future.

"We found that optimism continued to increase throughout young adulthood, seemed to steadily plateau and then decline into older adulthood," said William Chopik, MSU assistant professor of psychology at MSU and lead author. "Even people with fairly bad circumstances, who have had tough things happen in their lives, look to their futures and life ahead and felt optimistic."

The study, published in the Journal of Research in Personality, surveyed 75,000 American, German and Dutch people between the ages of 16 and 101 to measure optimism and their outlook about the future. Chopik said the researchers looked at life events such as: marriage, divorce, a new job, retirement, changes in health and loss of a partner, a parent or a child.

"Counterintuitively -- and most surprising -- we found that really hard things like deaths and divorce really didn't change a person's outlook to the future," Chopik said. "This shows that a lot of people likely subscribe to the 'life is short' mantra and realize they should focus on things that make them happy and maintain emotional balance."

Chopik explained that regardless of life's good and bad circumstances, from the time people are 15 to almost 60 or 70, they become more and more optimistic.

"There's a massive stretch of life during which you keep consistently looking forward to things and the future," Chopik said. "Part of that has to do with experiencing success both in work and life. You find a job, you meet your significant other, you achieve your goals and so on. You become more autonomous and you are somewhat in control of your future; so, you tend to expect things to turn out well."

As people age into the elderly phase of life, the study showed a shift to declines in optimism, likely driven by health-related concerns and knowing that the bulk of life is behind you. While the elderly aren't full-fledge pessimists, Chopik said, there is still a noticeable change.

"Retirement age is when people can stop working, have time to travel and to pursue their hobbies," Chopik said. "But very surprisingly, people didn't really think that it would change the outlook of their lives for the better."

Chopik said one of the most profound conclusions in the study was showing how resilient people are in life.

"We oftentimes think that the really sad or tragic things that happen in life completely alter us as people, but that's not really the case," Chopik said. "You don't fundamentally change as a result of terrible things; people diagnosed with an illness or those who go through another crisis still felt positive about the future and what life had ahead for them on the other side."

A loner and a hunter with highly developed territorial instincts, a cruel carnivore, a disobedient individual: the cat. These features make the species averse to domestication. Even so, we did it. Nowadays, about 500 million cats live in households all around the world; it is also difficult to estimate the amount of the homeless and the feral ones

Although the common history of cats and people began 10,000 years ago, the origins of the relation still remain unknown. How was the domestication process carried out? When did the first domesticated cats appear in Central Europe? Where did they come from, and how? What was their role in contemporary people's lives. The knowledge gaps in the topic are numerous; thus, archaeologists, archaeozoologists, biologists, anthropologists as well as other researchers all around the world cooperate to find answers to the questions. Scientists from the Institute of Archaeology at the Nicolaus Copernicus University in Torun have outstanding merits in this field. An article discussing significant research achievements in the area has been published in PNAS, a prestigious official journal of the National Academy of Sciences. The first author is Dr Magdalena Krajcarz who has made an attempt to find ancestors of domestic cats in Neolithic Central Europe. By analyzing cat diet, she is trying to check how close they cohabitated with people

Winding paths of the domesticated cat

According to the assumptions made, the deliberate creation of a breed which involved selecting particular individuals, cross-breeding and reproducing them, took place relatively recently, in the 19th century. In Medieval Poland, cats were not as popular as we could think. According to evidence provided by researchers, semi-domesticated weasels, or even snakes, were used to protect grain crops against rodents. These were people who settled in towns founded in the second half of the 13th century who increased the popularity of cats.

It does not mean, however, that cats had entered into no relations with people even earlier. The first, best-documented domesticated cat remains on the territory of Poland date back to the beginnings of our era. The animals are believed to have spread across Central Europe mainly due to the influence of the Roman Empire. Nonetheless, the earliest cat remains in the area date back to even 4,200-2,300 BC and evidence the first migrations of the Nubian cat which originally inhabited the Near East and North Africa. This particular species is considered as the ancestor of domestic cats in Central Europe.

The Nubian cat is one of wildcat subspecies (next to the European wildcat which is not the domestic cat ancestor even though it is able to cross-bread with it) whose domestication began in the Fertile Crescent ca. 10,000 - 9.000 years ago. In archaeological excavation sites in Anatolia, Syria as well as Israel, a variety of stone figurines representing those cats has been found. Apparently, cats stayed in the proximity of the first farmers and, with high probability, the Neolithic Age is when the first human-cat interrelations were initiated. People gave up nomadism in favor of sedentary life and started to gather eatables which, consequently, attracted rodents of many kinds. This could result in attracting wild cats to easily achievable food sources and the benefits turned out to be mutual. With much likelihood, cats remained rather neutral to people.

Cat skeleton analyses, together with the mammal iconography, allow researchers to make an assumption that cats reached Europe migrating from the Near East, through Anatolia, Cyprus, Crete, Greece, to Ancient Rome, where they were taken over by Celts and Germans .

Cat diet vs the history of domestication

The role cats played in Late Neolithic Poland is not clear since scientists have little evidence of these animals presence. The remains found come from caves rather than from human settlements which means that cats not necessarily had to be buried by men. They could as well be pray to other predators or they simply lived and died in caves. Nevertheless, researchers do not reject the hypothesis which says that the animals could be kept by men in order to protect crops from rodents, and thus, benefit from their skills, and occasionally follow them to the caves which contemporary people used as shelters.

Research performed by Dr Magdalena Krajcarz helps to resolve the mystery. In the article entitled Ancestors of domestic cats in Neolithic Central Europe: Isotopic evidence of a synanthropic diet published in PNAS, she provides an insight into cats diet in order to determine how close human-cat relations were.

To carry out studies, six Neolithic cat remains of the Near East characteristics from four cave sites in the Kraków- Czestochowa Upland (southern Poland) were used. Nearby, there used to be farmer settlements located on fertile soils. Moreover, four European wildcat remains from an analogous period and area as well as three Pre-Neolithic and two others from the Roman Period were examined. The reference material additionally covered human and other animal remains.

Analyzing stable carbon and nitrogen isotopes in bone collagen constituted the methodological basis. The stable isotope analysis method is a commonly applied tool in the paleontology and ecology of animals because the isotope composition of their remains reflects the isotope composition of food. According to Krajcarz, the method enables, for example, the identification of feeding habits of particular fossil animal species. In research on wild animal feeding habits, conventional techniques involve analyzing food remnants in faeces or stomachs, which imposes significant limitations. Most importantly, not all the remnants can be identified. Moreover, the remnants are from the last feeding. Finally, the access to such fossil material is very poor.

Owing to the isotope analysis, taking accurate chemical measurements as well as recognizing average diet covering the whole animal lifespan are possible. Primarily, the method allows the examination of feeding habits of animals from the past. All we have are bone tissue remnants which have survived in the unaltered state as the isotope composition of bones has been unchanged for thousands of years - says Dr Krajcarz. To simplify the issue, the Neolithic farmers were knowledgeable enough to apply fertilizers such as dung or plant ash. Rodents which fed on the collected crops were consumed by cats. By the stable isotopes examination we are able to decide whether contemporary cats found food taking advantage of human activity somehow.

So, what are the conclusions drawn by the researchers? According to the examination results, the Near East cats were not fully dependent on men. They made use of all the available food sources, but could also find others in their habitat. They could do it periodically, either benefiting from human activity or hunting individually in forests. Thus, they maintained their independence.

As Dr Krajcarz explains, their findings confirm the hypothesis that the Near East wildcats have spread across Europe accompanying the first farmers, probably as commensal animals. The results of the stable isotope analysis obtained for the Roman Period cats. however, seem to resemble those of men and dogs which suggests that cats followed a similar diet, i.e. they benefited from human resources or were possibly fed by men. Also, the development in farming partially influenced our native European wildcat, even if it was more forest resources oriented.

On the track of the cat history

Dr Magdalena Krajcarz and Prof. Daniel Makowiecki from the Institute of Archaeology at the Nicolaus Copernicus University are continuing their research on the history of domestic cats. Together with a team of paleogeneticians supervised by Dr Danijela Popovi? from the Warsaw University, they are initiating a new research project, 5,000 Years of History of Domestic Cats in Central Europe: an Interdisciplinary Paleogenetic and Archaeozoological Study funded by the National Centre of Science. The project will be based on the international cooperation with researchers representing European institutions including Belgium, Serbia, Lithuania, Slovakia, and the Czech Republic.

The main aim of the four year project is to reconstruct migration trails of domestic cats from their domestication regions to Europe and look for traces of the cat genome selection, natural and/or controlled by men. The research team is planning to analyze hundreds of cat bone remains from archaeological and paleontological sites. In the interdisciplinary project, conventional archaeozoological and paleontological morphometric methods as well as fossil DNA analysis and radiocarbon dating will be employed.

The researchers wish to trace all the phenotypic and genetic changes in cats which are responsible for domestication (aesthetic: size, coloration; behavioral: reducing aggression; physiological: adopting to digest anthropogenic food, e.g. milk, starch).

On the basis of the genomic data, they want to estimate the cross-breeding intensity of the Nubian cat and the European wildcat in order to check whether it increased together with the domestic cat population expansion.

DURHAM, N.C. -- Frogs and toads are green for a very good reason - it makes them harder to see in their leafy environments. Good camouflage allows them to eat and not be eaten. But not all frogs have arrived at this life-saving greenness in the same way.

Most of these animals rely on color-controlling structures in their skin called chromatophores that use crystals to bend light to specific colors and make them appear green. But there are hundreds of species of frogs and toads that have nearly translucent skin and very few chromatophores.

Their greenness, which can be found deep in their lymphatic fluid, soft tissues and even bones, comes from a clever biochemical workaround that combines a normally virus-fighting type of protein with a toxic byproduct of blood breakdown.

The finding, by post-doctoral researcher Carlos Taboada at Duke University, solves a few longstanding mysteries about these frogs and shows how the necessity of survival can be very inventive indeed. It appears the week of July 13 in the Proceedings of the National Academy of Sciences.

Scientists have long grappled with the fact that many of these frogs contain very high levels of bile pigment called biliverdin that is a byproduct of breaking apart old red blood cells. This pigment is normally considered a toxin to be filtered out in the liver and excreted as quickly as possible. But these frogs are found to carry four times as much biliverdin as even the sickest human with liver disease, and 200 times as much as their chromatophore-equipped frog cousins.

To understand the biochemistry better, the researchers focused on one species, Boana punctata, the polka-dot treefrog of South America. From it, they isolated a protein they're calling BBS (biliverdin-binding serpin), which is part of a superfamily of protease inhibitors, the proteins that normally step in the way of viral replication and detoxify enzymes.

When you see something green, its color really should be called 'everything but green,' because it is soaking up all the colors of incoming light except for green. The color we see is the frequency of light it does not absorb that bounces back to our eyes.

Biliverdin by itself would appear to be somewhat greenish, as sometimes seen in an old bruise, but the researchers found that a bound serpin, BBS, stretches out biliverdin's helical shape to fine-tune its light absorbance, making it more cyan, a blue-green. Cyan, added to some other yellow pigments scattered in the skin, bounces back just the right shade of green. It also makes biliverdin less toxic as well, apparently.

"This new protein has the same spectroscopic properties or light absorption properties as some plant pigments," said Taboada, who began the work in Argentina, Ecuador and Brazil and completed it at Duke. "The light properties are very similar to what we see, for example, in some plant proteins called phytochromes. But here we have a completely different protein."

It's a clever adaptation of existing biochemistry that normally serves other functions in vertebrates. Taboada said this innovation has evolved more than 40 times across 11 different families, most of them treefrogs. The adaptation happened again and again in far-flung Madagascar, South America and Southeast Asia.

"So this is a convergence in evolution," Taboada said. "Being arboreal (living in trees), they developed a different way to make their coloration." Their through-and-through greenness ensures good camouflage on foliage, even in near-infrared light.

"This shows how natural selection can co-opt proteins for just about any purpose," said Sönke Johnsen, a professor of biology at Duke and coauthor on the paper. "Biliverdin is a bile pigment that would normally be excreted from the body because of its potential for harm, but here it is in spectacular concentrations precisely because it's also useful as a green pigment."

"In other words, Kermit has jaundice," Johnsen said.

Having earlier discovered that many species of frogs reflect fluorescent wavelengths - essentially glowing in the dark - Taboada is now working with engineers at Duke's Pratt School of Engineering to shine precisely tuned lasers at frogs to learn more about their coloration.

AMHERST, Mass. - A chemist and kinesiologist got on a bus, but this isn't the set-up to a joke. Instead, kinesiologist and lead author Ned Debold and chemist Dhandapani Venkataraman, "DV," began talking on their bus commute to the University of Massachusetts Amherst and discovered their mutual interest in how energy is converted from one form to another - for Debold, in muscle tissue and for DV, in solar cells.

Debold told the chemist how researchers have been seeking an alternative energy source to replace the body's usual one, a molecule called adenosine triphosphate (ATP). Such a source could control muscle activity, and might lead to new muscle spasm-calming treatments in cerebral palsy, for example, or activate or enhance skeletal muscle function in MS, ALS and chronic heart failure.

All are highly debilitating because the body has no way to fix them, says muscle physiologist Debold. It doesn't have good mechanisms to control - either inhibit or boost - myosin function, the molecular motor that drives movement.

As DV notes, the usual approach to seeking a new compound is to systematically test each one among millions until one seems worth followup - the classic "needle in a haystack" approach. He says, "At one point I suggested to Ned, 'Why don't we build the needle ourselves instead?' That started us on this interesting project that put together people who would otherwise never work together."

The two soon saw that they would need someone to model interactions between the molecules DV was making and the myosin molecules Debold was using to test them. They invited computational chemist Jianhan Chen.

Chen explains, "We did computer modeling because experimentally it is difficult to know how myosin might be using the molecules DV was synthesizing. We can use computer simulation to provide a detailed picture at the molecular level to understand why these compounds might have certain effects. This can provide insight into not only how myosin interacts with the current set of compounds, but also it can provide a roadmap for DV to use to design new compounds that are even more effective at altering myosin function."

This month, the researchers report in the Biophysical Journal that they have made a series of synthetic compounds to serve as alternative energy sources for the muscle protein myosin, and that myosin can use this new energy source to generate force and velocity. Mike Woodward from the Debold lab is the first author of their paper and Xiaorong Liu from the Chen lab performed the computer simulation.

By using different isomers - molecules with atoms in different arrangements - they were able to "effectively modulate, and even inhibit, the activity of myosin," suggesting that changing the isomer may offer a simple yet powerful approach to control molecular motor function. With three isomers of the new ATP substitute, they show that myosin's force- and motion-generating capacity can be dramatically altered. "By correlating our experimental results with computation, we show that each isomer exerts intrinsic control by affecting distinct steps in myosin's mechano-chemical cycle."

DV recalls, "My lab had never made such types of compounds before, we had to learn a new chemistry; my student Eric Ostrander worked on the synthesis." The new chemistry involves sticking three phosphate groups onto a light-sensitive molecule, azobenzene, making what the researchers now call Azobenzene triphosphate, he adds.

The next stage for the trio will be to map the process at various points in myosin's biochemical cycle, Debold says. "In the muscle research field, we still don't fully understand how myosin converts energy gain from the food we eat into mechanical work. It's a question that lies at the heart of understanding how muscles contract. By feeding myosin carefully designed alternative energy sources, we can understand how this complex molecular motor works. And along the way we are likely to reveal novel targets and approaches to address a host of muscle related diseases."

A new UC Davis Eye Center study, conducted in collaboration with France's INSERM Stem Cell and Brain Research Institute, found that special patented glasses engineered with technically advanced spectral notch filters enhance color vision for those with the most common types of red-green color vision deficiency ("anomalous trichromacy"). Notably, the ability to identify and experience expanded color was also demonstrated when color blind test subjects were not wearing the glasses.

At least eight in 100 men (8%) and one in 200 women (0.5%) suffer from red-green color vision deficiency (CVD), totaling 13 million in the U.S. and 350 million worldwide. While those with normal color vision see in excess of one million hues and shades, those with CVD see a vastly diminished range of colors. People with CVD experience colors as more muted and washed out, and some colors cause confusion or are more difficult to differentiate. With an undergraduate and graduate student body of nearly 40,000, UC Davis has an estimated 1,700 students with red-green CVD.

The study evaluated the impact of spectral notch filters on enhancing the chromatic responses of observers with red-green CVD over two weeks of usage. The filters (EnChroma glasses) are designed to increase the separation between color channels to help people with color blindness see colors more vibrantly, clearly and distinctly.

The research, published in Current Biology, had CVD participants wear the special filter glasses or placebo glasses. Over two weeks, they kept a diary and were re-tested on days 2, 4 and 11 but without wearing the glasses. The researchers found that wearing the filter glasses increased responses to chromatic contrast response in individuals with red-green color blindness. It is unclear how long the improvement lasts without wearing the filters, but the evidence shows that the effect persists for some time.

"Extended usage of these glasses boosts chromatic response in those with anomalous trichromacy (red-green color vision deficiency)," said John S. Werner, distinguished professor of ophthalmology and a leader in vision science at UC Davis Health. "We found that sustained use over two weeks not only led to increased chromatic contrast response, but, importantly, these improvements persisted when tested without the filters, thereby demonstrating an adaptive visual response."

Werner noted that this effect cannot be achieved with broad-band filters sold as aids to the color blind. He and his research colleagues believe the study's findings suggest that modifications of photoreceptor signals activate a plastic post-receptoral substrate in the brain that could potentially be exploited for visual rehabilitation.

"When I wear the glasses outside, all the colors are extremely vibrant and saturated, and I can look at trees and clearly tell that each tree has a slightly different shade of green compared to the rest," said Alex Zbylut, one of the color blind participants in the study who got the placebo glasses first and then tried the special filter version afterwards. "I had no idea how colorful the world is and feel these glasses can help color blind people better navigate color and appreciate the world."

Reactions from other participants about their experiences with the glasses can be found in the Supplement section of the Current Biology article.