Earth

No matter where we look, the same rules apply everywhere in space: countless calculations of astrophysics are based on this basic principle. A recent study by the Universities of Bonn and Harvard, however, has thrown this principle into question. Should the measured values be confirmed, this would toss many assumptions about the properties of the universe overboard. The results are published in the journal Astronomy & Astrophysics, but are already available online.

Since the big bang, the universe has swollen like a freshly formed raisin roll put in a warm place to rise. Until recently, it was thought that this increase in size was occurring evenly in all directions, as with a good yeast dough. Astrophysicists call this "isotropy". Many calculations on the fundamental properties of the universe are based on this assumption. It is possible that they are all wrong - or at least, inaccurate - thanks to compelling observations and analyses of the scientists from the Universities of Bonn and Harvard.

For they have put the isotropy hypothesis to the test for the first time with a new method that allows more reliable statements than before. With an unexpected result: According to this method, some areas in space expand faster than they should, while others expand more slowly than expected. "In any case, this conclusion is suggested by our measurements," states Konstantinos Migkas, from the Argelander Institute for Astronomy at the University of Bonn.

Migkas and his colleagues have developed a new, efficient isotropy test in their study. It is based on the observation of so-called galaxy clusters - in a sense, the raisins in the yeast bun. The clusters emit X-ray radiation that can be collected on Earth (in this case, this was done by the satellite-based telescopes Chandra and XMM-Newton). The temperature of the galaxy clusters can be calculated based on certain characteristics of the radiation. Also, their brightness can be measured. The hotter they are, the brighter they glow.

In an isotropic universe, a simple rule applies. The further away a celestial object is from us, the faster it moves away from us. From its speed, we can therefore deduce its distance from us, regardless of the direction in which the object lies. At least that's what we thought until now. "In reality, however, our brightness measurements seem to disagree with the above distance calculation," Migkas emphasizes.

This is because the amount of light that reaches the earth decreases with increasing distance. So, anyone who knows the original luminosity of a celestial body and its distance knows how bright it should shine in the telescope image. And it is precisely at this point that scientists have come across discrepancies that are difficult to reconcile with the isotropy hypothesis: that some galaxy clusters are much fainter than expected. Their distance from Earth is probably much greater than calculated from their speed. And for some others, however, the opposite is the case.

"There are only three possible explanations for this," states Migkas, who is doing his doctorate in the research group of Prof. Dr. Thomas Reiprich at the Argelander Institute. "Firstly, it is possible that the X-ray radiation, whose intensity we have measured, is attenuated on its way from the galaxy clusters to Earth. This could be due to as yet undiscovered gas or dust clouds inside or outside the Milky Way. In preliminary tests, however, we find this discrepancy between measurement and theory not only in X-rays but also at other wavelengths. It is extremely unlikely that any kind of matter nebula absorbs completely different types of radiation in the same way. But we won't know for sure for several months."

A second possibility are so-called "bulk flows". These are groups of neighboring galaxy clusters that move continuously in a certain direction - for example, due to some structures in space that generate strong gravitational forces. These would therefore attract the galaxy clusters to themselves and thus change their speed (and thus also their derived distance). "This effect would also mean that many calculations on the properties of the local universe would be imprecise and would have to be repeated," explains Migkas.

The third possibility is the most serious: What if the universe is not isotropic at all? What if - metaphorically speaking - the yeast in the galactic raisin roll is so unevenly distributed that it quickly bulges in some places while it hardly grows at all in other regions? Such an anisotropy could, for example, result from the properties of the mysterious "dark energy", which acts as an additional driving force for the expansion of the universe. However, a theory is still missing that would make the behavior of the Dark Energy consistent with the observations. "If we succeed in developing such a theory, it could greatly accelerate the search for the exact nature of this form of energy," Migkas is certain.

The current study is based on data from more than 800 galaxy clusters, 300 of which were analysed by the authors. The remaining clusters come from previously published studies. The analysis of the X-ray data alone was so demanding that it took several months. The new satellite-based eROSITA X-ray telescope is expected to record several thousand more galaxy clusters in the coming years. At the latest then it will become clear whether the isotropy hypothesis really has to be abandoned.

Amsterdam, NL, April 8, 2020 - Clinical neuropsychology and psychology have evolved as diagnostic and treatment-oriented disciplines necessary for individuals with neurological, psychiatric, and medical conditions. In this collection of articles in the journal NeuroRehabilitation experts highlight medical advances in neuropsychological and psychological applications in neurorehabilitation.

"Neuropsychology and psychology are practical disciplines that provide the underpinnings for understanding etiology and formulating diagnoses, and they serve as the cornerstones of some of the most successful neurorehabilitative treatment approaches," explained guest editor Dr. Vivian L. Begali, PsyD, Neuropsychology and Psychological Healthcare, Richmond, VA, USA. "This thematic issue aims to exemplify the advantages of neuropsychological and psychological principles and their influential role in rehabilitation, The central focus is brain dysfunction occurring from traumatic injury or a more insidious process such as progressive brain disease, or as the result of abrupt and sudden interruption in normal cerebral blood flow (stroke)."

Neuropsychological and psychological applications in neurorehabilitation encompass a broad range of services including direct clinical work (e.g., assessment, psychotherapy, psychoeducation, behavioral management); medical, family and agency consultation; experimental and clinical research; community reintegration; vocational rehabilitation; forensic applications; and therapeutic end-of-life planning.

The articles in this collection address multiple etiologies, recovery of function, brain plasticity, functional outcomes following neurological injury, method research, experimental methodologies and include illustrative case studies. Collectively, they address stroke, traumatic brain injury (TBI), persistent sport-related post-concussive syndrome, and the dementia spectrum. Two innovative and provocative treatment methodologies are described: solution-focused brief therapy (SFBT) and medical assessment counseling. Rounding out this issue are the findings of two original research studies, one on the predictors of depression trajectories following hospitalization for TBI in Latin America, and the other on community reintegration outcomes at 30 years post-discharge from holistic milieu-oriented neurorehabilitation.

The issue includes multiple examples of the intersection between medicine, diagnoses, and need for practical information. Lead author Dr. Robert Conder, PsyD, Carolina Neuropsychological Service, Raleigh, NC, USA, and colleagues highlight the importance of identifying and differentiating co-occurring symptoms such as depression, anxiety, migraines, insomnia, and attention deficits in order to prevent misdiagnosis of persistent sport-related post-concussion syndrome and lead to more effective treatment outcomes.

"There is much misunderstanding about the etiology, causation, diagnostic formulations, symptom presentation, prolonging factors, and treatment involved in this syndrome," commented Dr. Conder. "We posit an individualized multisystem diagnostic formulation, examining all relevant factors, as generating the best interventions for neurorehabilitation of patients with this syndrome."

An article on community reintegration following holistic milieu-oriented neurorehabilitation up to 30 years post discharge offers a glimpse into the real-life advantages of a holistic approach to neurorehabilitation. Lead author Dr. Pamela S. Klonoff, PhD, Director, Center for Transitional Neuro-Rehabilitation, Barrow Neurological Institute/St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA, writes, "The benefits of this approach stem from its emphasis on improving self-awareness and metacognition when combined with interpersonal and functional skills redevelopment. The results of our study demonstrated that 89% of patients who had acquired significant brain injury were productive at up to 30 years post-discharge as determined by degree of work or school re-engagement, driving, and psychosocial success."

"The core principles of psychotherapy such as listening, reflection, support, empathy, confrontation, problem identification, solution orientation, integration, relationship building, awareness and insight, and the reduction of discomfort remain just as, if not more relevant, following neurological injury," added Dr. Begali. "Ultimately, the process of neurorehabilitation is a personalized, integrated transdisciplinary undertaking that helps ameliorate, modify, and compensate for the effects of impairment caused by nervous system injury. Neuropsychological and psychological methods are essential components of the neurorehabilitative process for individuals with acquired central nervous system injury."

A homogeneous, consistent, high-quality in situ temperature data set covering some decades in time is crucial for the detection of climate changes in the ocean.

Systematic errors in the global archive of temperature profiles pose a significant problem for the estimation and monitoring of the global ocean heat content, a most reliable indicator of climate change. During almost four decades between 1940-1970s the majority of temperature observations in the ocean within the upper 200 meters was obtained by means of mechanical bathythermographs (MBT). Actually MBT contributes to 68% of ocean subsurface data within 1940-1966.

The new study by Viktor Gouretski and Lijing Cheng from the Institute for Atmospheric Physics, Beijing, published in the Journal of Atmospheric and Oceanic Technology investigates the quality of MBT data by comparing these data with reference profiles obtained by means of Nansen bottle casts and Conductivity-Temperature-Depth profilers (CTD).

This comparison reveals significant systematic errors in MBT data. The MBT temperature bias is as large as 0.2°C before 1980 on the global average and reduces to less than 0.1°C after 1980. To eliminate this bias from the original data a new empirical correction scheme for MBT data is derived, where the MBT correction is country-, depth, and time- dependent.

Several bias correction schemes were tested. In order to objectively assess the performance of the schemes, four metrics were introduced and for each correction scheme and bias reduction factors were calculated. The scheme accounting for the depth bias and the thermal bias showed the best performance significantly reducing the original bias. Further, the new MBT correction scheme suggests a better performance compared with three MBT correction schemes proposed earlier in the literature (from Japan, United States of America and Germany).

The reduction of the biases increases the homogeneity of the global ocean database being mostly important for climate change related studies, such as the improved estimation of the ocean heat content changes.

"This new technique will be used in IAP ocean gridded temperature product and ocean heat content estimate in 2020." said CHENG, "We expect it to significantly improve their quality during the 1940-1970 period."

This study is funded by National Key R&D Program (2016YFC1401800 and 2017YFA0603202) and Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI).

The Biological Dynamics of Forest Fragments Project (BDFFP), located near Manaus, Brazil, began in 1979 and is the world's longest-running experimental study of tropical forest fragments. A new paper in The Condor: Ornithological Applications summarizes four decades of data from the project about how Amazonian bird communities respond to habitat fragmentation, a question as relevant today as ever in light of the recent increase in deforestation in the Amazon.

Louisiana State University's Phil Stouffer, who authored the new paper, led bird research at the Biological Dynamics of Forest Fragments Project from 1991 to 2019. As he describes, studying the changes in bird communities over the forty years following habitat fragmentation led to some surprises. The original plan was to monitor "forest islands" permanently isolated by surrounding cattle pastures, but changes in the Brazilian economy led to the abandonment of the cattle pastures within a few years after their establishment. As trees began to regrow in the areas surrounding the fragments, forest bird species that had initially disappeared began to recolonize the fragments, highlighting the unexpected value of second-growth habitat for rainforest birds. Additional work yielded both good and bad news for fragment-dwelling birds -- for example, non-forest bird species typically didn't invade forest fragments, but even very narrow strips of deforested land could limit the movement of forest-dependent species.

"The long history of the project allowed us to follow changes in the avifauna rather than just trying to interpret what we saw in any particular slice of time," says Stouffer. "This project was important for stepping away from the idea that habitat fragments are analogous to actual islands -- the modern interpretation is a lot more nuanced, and the recovery of birds in second-growth forest provides encouraging evidence that many rainforest birds can use deforested areas that are allowed to regrow. Our challenge now is to determine under what conditions remnant patches and second growth can support rich Amazonian bird communities." Another issue that the BDFFP hopes to address in the near future is one that didn't even exist when the project began: what has climate change done to Amazonian birds since 1979, and what does the future hold?

Working in Manaus once meant being isolated from the global scientific community, but no more -- BDFFP scientists even hosted an international ornithological conference there in 2015. "On the 40th anniversary of the BDFFP, it seems appropriate to summarize what we've learned. It's also important to reflect on how technical advances that we now take for granted in modern fieldwork were incorporated into the project. For example, digital photography helped resolve criteria for determining the ages of Amazonian birds and GPS technology allows us to determine bird locations and movement with high precision, goals unimaginable when I started at the BDFFP," says Stouffer.

In a recent Journal of Sleep Research study, participants perceived pleasant and neutral pictures in a more negative way when their sleep was restricted for several nights in a row.

In the study, participants were tested the morning after 5 nights of regular sleep and after 5 consecutive nights of sleep restriction (5 hours a night).

"Insufficient sleep may impose a negative emotional bias, leading to an increased tendency to evaluate emotional stimuli as negative," said lead author Daniela Tempesta, PhD, of the University of L'Aquila, in Italy. She noted that the findings are especially pertinent because chronic sleep restriction is a common and underestimated health problem in the general population. "Considering the pervasiveness of insufficient sleep in modern society, our results have potential implications for daily life, as well as in clinical settings."

Researchers from Cambridge, UK, and Germany have reconstructed the early "evolutionary paths" of COVID-19 in humans - as infection spread from Wuhan out to Europe and North America - using genetic network techniques.

By analysing the first 160 complete virus genomes to be sequenced from human patients, the scientists have mapped some of the original spread of the new coronavirus through its mutations, which creates different viral lineages.

"There are too many rapid mutations to neatly trace a COVID-19 family tree. We used a mathematical network algorithm to visualise all the plausible trees simultaneously," said geneticist Dr Peter Forster, lead author from the University of Cambridge.

"These techniques are mostly known for mapping the movements of prehistoric human populations through DNA. We think this is the first time they have been used to trace the infection routes of a coronavirus like COVID-19."

The team used data from virus genomes sampled from across the world between 24 December 2019 and 4 March 2020. The research revealed three distinct "variants" of COVID-19, consisting of clusters of closely related lineages, which they label 'A', 'B' and 'C'.

Forster and colleagues found that the closest type of COVID-19 to the one discovered in bats - type 'A', the "original human virus genome" - was present in Wuhan, but surprisingly was not the city's predominant virus type.

Mutated versions of 'A' were seen in Americans reported to have lived in Wuhan, and a large number of A-type viruses were found in patients from the US and Australia.

Wuhan's major virus type, 'B', was prevalent in patients from across East Asia. However, the variant didn't travel much beyond the region without further mutations - implying a "founder event" in Wuhan, or "resistance" against this type of COVID-19 outside East Asia, say researchers.

The 'C' variant is the major European type, found in early patients from France, Italy, Sweden and England. It is absent from the study's Chinese mainland sample, but seen in Singapore, Hong Kong and South Korea.

The new analysis also suggests that one of the earliest introductions of the virus into Italy came via the first documented German infection on January 27, and that another early Italian infection route was related to a "Singapore cluster".

Importantly, the researchers say that their genetic networking techniques accurately traced established infection routes: the mutations and viral lineages joined the dots between known cases.

As such, the scientists argue that these "phylogenetic" methods could be applied to the very latest coronavirus genome sequencing to help predict future global hot spots of disease transmission and surge.

"Phylogenetic network analysis has the potential to help identify undocumented COVID-19 infection sources, which can then be quarantined to contain further spread of the disease worldwide," said Forster, a fellow of the McDonald Institute of Archaeological Research at Cambridge, as well as the University's Institute of Continuing Education.

The findings are published today in the journal Proceedings of the National Academy of Sciences (PNAS). The software used in the study, as well as classifications for over 1,000 coronavirus genomes and counting, is available free at http://www.fluxus-technology.com.

Variant 'A', most closely related to the virus found in both bats and pangolins, is described as "the root of the outbreak" by researchers. Type 'B' is derived from 'A', separated by two mutations, then 'C' is in turn a "daughter" of 'B'.

Researchers say the localisation of the 'B' variant to East Asia could result from a "founder effect": a genetic bottleneck that occurs when, in the case of a virus, a new type is established from a small, isolated group of infections.

Forster argues that there is another explanation worth considering. "The Wuhan B-type virus could be immunologically or environmentally adapted to a large section of the East Asian population. It may need to mutate to overcome resistance outside East Asia. We seem to see a slower mutation rate in East Asia than elsewhere, in this initial phase."

He added: "The viral network we have detailed is a snapshot of the early stages of an epidemic, before the evolutionary paths of COVID-19 become obscured by vast numbers of mutations. It's like catching an incipient supernova in the act."

Since today's PNAS study was conducted, the research team has extended its analysis to 1,001 viral genomes. While yet to be peer-reviewed, Forster says the latest work suggests that the first infection and spread among humans of COVID-19 occurred between mid-September and early December.

The phylogenetic network methods used by researchers - allowing the visualisation of hundreds of evolutionary trees simultaneously in one simple graph - were pioneered in New Zealand in 1979, then developed by German mathematicians in the 1990s.

These techniques came to the attention of archaeologist Professor Colin Renfrew, a co-author of the new PNAS study, in 1998. Renfrew went on to establish one of the first archaeogenetics research groups in the world at the University of Cambridge.

Unlike humans, sea turtles and other reptiles like crocodiles do not have sex chromosomes. Their sex is defined during development by the incubation environment. In sea turtles, sex is determined by the nest's temperature: warmer temperatures produce females and cooler temperatures produce males. It is especially challenging to identify the sex of hatchling sea turtles because they lack external sexual organs and heteromorphic sex chromosomes -- no X or Y. To date, there are a limited number of ways to reliably identify sex in turtle hatchlings. With the rapid increase of global temperatures, there is an urgent need to clearly assess sex ratios in these imperiled animals.

Researchers from Florida Atlantic University's Charles E. Schmidt College of Science have developed a first-of-its-kind technique that is minimally invasive and greatly enhances the ability to measure neonate turtle sex ratios at population levels across nesting sites worldwide. They used this technique to identify sex in neonates of two turtle species: a freshwater turtle (Trachemys scripta) and a marine turtle (Caretta caretta) using analysis of small blood samples. This is the first time that differences in sex-specific protein expression patterns have been identified in blood samples of hatchlings with temperature-dependent sex determination. This research is a crucial step in assessing the impact of climate change on imperiled turtle species.

For the study, published in Scientific Reports, researchers used an immunoassay approach to test samples for the presence of several proteins known to play an important role in sex differentiation. Results of the study showed that anti-müllerian hormone (AMH) can reliably be detected in blood samples from neonate male turtles but not females and can be used as a sex-specific marker.

Researchers verified the sex of the turtles using histology or laparoscopy, which revealed that the new method they developed is 100 percent reliable for identifying sex in both the freshwater turtle and the loggerhead sea turtle in 1- to 2-day-old hatchlings and was 90 percent reliable for identifying sex in 83- to 177-day-old (120 - 160g) loggerhead juveniles.

"The challenges inherent in the methods that are currently being used to identify the sex of neonate turtles with temperature-dependent sex determination is what inspired us to look for an alternative approach," said Jeanette Wyneken, Ph.D., co-author and a professor of biological sciences in FAU's Charles E. Schmidt College of Science. "Results from our study provide the field of reptile conservation, and in particular, turtle conservation and management, with a valuable new tool that can be used to accurately assess the sex ratios of hatchlings."

In comparison to the current molecular methods for sex identification in turtles with temperature-dependent sex differentiation, the approach developed by FAU researchers using blood samples via western blot analysis is quick, minimally invasive (requires a very small volume of blood), and the hatchling turtle can then be released immediately.

"Information from our study should enable other scientists and managers to precisely monitor changes in sex ratios that might arise as a consequence of changes in temperature over time," said Boris Tezak, Ph.D., senior author who conducted the research as part of his Ph.D. studies at FAU and is now a post-doctoral researcher at Duke University Medical Center. "It also will help them to estimate how climate change will affect future generations of hatchlings, and allow for expedited evaluation of management strategies used to help recover imperiled sea turtles and other reptile species with temperature-dependent sex determination."

Identifying natural turtle hatchling sex ratios at nesting sites is challenging for a variety of reasons, spanning morphological limitations to ethical issues to a lack of understanding of the mechanisms that actually direct embryonic sexual differentiation. Generally, turtles are characterized by being long-lived and late-maturing, so they are not sexually dimorphic until approaching sexual maturity - marine turtle species often take more than 25 years to become sexually mature.

"Due to the difficulties associated with readily identifying hatchling sex, most large-scale studies investigating turtle hatchling sex ratios rely on proxies to infer sex ratios indirectly such as nest temperatures, air temperatures or nest incubation durations," said Itzel Sifuentes-Romero, Ph.D., co-author, a post-doctoral fellow of biological sciences in FAU's Charles E. Schmidt College of Science, and a post-doctoral fellow of FAU's Brain Institute (I-Brain). "However, these alternatives often fail to match the primary sex ratios from natural turtle nests or rookeries. We believe that the novel technique we have developed will allow for more accurate estimates of hatchling sex ratios at a population level and on a global scale."

Some flowers have a remarkable and previously unknown ability to bounce back after injury, according to a new study.

Some injured flowers bent and twisted themselves back into the best possible position to ensure successful reproduction within 10-48 hours of being knocked over, for example, by falling branches or being walked on.

The reproduction of many flowers (and survival of populations) depends on the perfect alignment of their sexual organs and nectar tubes in order for a visiting insect to pollinate them.

But some are better at recovering their alignment after an injury than others.

Professor of Ecology and Evolution Scott Armbruster, at the University of Portsmouth, published his findings in New Phytologist.

He said: "Mechanical accidents happen to plants fairly often and can, in some cases, stop the plant from being able to attract pollinating insects and so, make seeds. Making seeds and propagating is a flower's main purpose, so injuries which threaten that pose a huge problem."

The study found that bilaterally symmetrical flowers - those in which the left and right sides mirror each other, such as snapdragon, orchid, and sweet pea - can almost always restore their 'correct' orientation by moving individual flower stems or even moving the stalk that supports a cluster of flowers.

In some cases, bilaterally symmetrical flowers can accurately re-position their stigma - a sexual organ - after injury.

Plants' movement after an injury isn't only about making seeds; these plants were seen to bend or twist to make sure their leaves were again facing the Sun, necessary for photosynthesis, the process by which a plant produces its food.

Radially symmetrical flowers, star-shaped flowers, such as petunia, buttercup, and wild rose - lacked this ability and their stems rarely recovered after an injury.

Nearly all (95 per cent) of bilaterally symmetrical flowers examined moved after injury to restore the plant's ability to attract pollinators, while just four per cent of radially symmetrical flowers examined had moved post-injury. This is probably because floral orientation is usually more important for the efficient pollination of bilaterally symmetrical flowers than radially symmetrical ones.

"This little-known aspect of plant evolution is fascinating and tells us much more than we previously knew about how plants behaviourally adapt to changes in their environment, including mechanical accidents," Professor Armbruster said.

Professor Armbruster and his collaborator Nathan Muchhala (University of Missouri, St. Louis) studied 23 native and cultivated flower species in Australia, South America, North America and the UK.

They found four mechanisms involved, sometimes separately, sometimes all at once, in an injured flower reorienting itself:

Bending of the main supporting stalk of a cluster of flowers;

Bending of individual flower stalks (more likely in long stems);

Rotation of individual flower stalks (more likely in short stems);

Twisting or bending the flower's sexual organs.

The younger the plant part, the faster it managed to bend, meaning stalks supporting individual flowers at the end of a cluster were more easily moved, than the stronger and older stalks supporting an entire cluster.

"Because the outlook is grave for plant species which don't allow pollinating insects in or which have lost the connection between nectar and its sexual organs, we expected plants might have found a way around this, if, for example, they are hit by high winds or falling branches," Professor Armbruster said.

"What we found, in a haphazard sample of plants, was that bilaterally symmetrical flowers were able to use up to four methods of restoring their chances of being pollinated almost to pre-injury levels.

"This ability is, I'd argue, an under-appreciated behaviour worthy of closer scrutiny."

Australia's iconic Great Barrier Reef is experiencing its third coral bleaching event in just five years. The 2020 bleaching is severe, and more widespread than earlier events.

"We surveyed 1,036 reefs from the air during the last two weeks in March, to measure the extent and severity of coral bleaching throughout the Barrier Reef region," said Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

"For the first time, severe bleaching has struck all three regions of the Great Barrier Reef - the northern, central and now large parts of the southern sectors," Prof Hughes said.

Coral bleaching at regional scales is caused by thermal stress due to spikes in sea temperatures during unusually hot summers. The first recorded mass bleaching event along the Great Barrier Reef occurred in 1998, then the hottest year on record. Four more mass bleaching events have occurred since--as more temperature records were broken--in 2002, 2016, 2017, and now in 2020.

This year, February had the highest monthly temperatures ever recorded on the Great Barrier Reef since the Bureau of Meteorology's sea surface temperature records began in 1900.

"Bleaching isn't necessarily fatal, and it affects some species more than others," said Professor Morgan Pratchett, also from Coral CoE at JCU, who led underwater surveys to assess the bleaching.

"A pale or lightly bleached coral typically regains its colour within a few weeks or months and survives," he said.

However, many corals die when bleaching is severe. In 2016, more than half of the shallow-water corals died on the northern region of the Great Barrier Reef.

"We will go back underwater later this year to assess the losses of corals from this most recent event," Prof Pratchett said.

"The north was the worst affected region in 2016, followed by the central region in 2017. In 2020, the cumulative footprint of bleaching has expanded further to include the south."

The distinctive footprint of each bleaching event closely matches the location of hotter and cooler conditions in different years.

"As summers grow hotter and hotter, we no longer need an El Niño event to trigger mass bleaching at the scale of the Great Barrier Reef," Prof Hughes said.

"Of the five events we have seen so far, only 1998 and 2016 occurred during El Niño conditions."

The gap between recurrent bleaching events is shrinking, hindering a full recovery.

"We have already seen the first example of back-to-back bleaching--in the consecutive summers of 2016 and 2017," Prof Hughes said.

After five bleaching events, the number of reefs that have so far escaped severe bleaching continues to dwindle. Those reefs are located offshore, in the far north, and in remote parts of the south.

Physicists at the Center for Integrated Nanostructure Physics (CINAP), within the Institute for Basic Science (IBS, South Korea), have reported a new method to identify the aggregation state of amyloid beta (Aβ) proteins in solution. Published in ACS Nano, this finding could represent a step forward in the early diagnosis of Alzheimer's disease.

The gradual accumulation of Aβ in the brain leads to incurable dementia. The disease progression is strongly correlated with the form of the Aβ proteins: 4-nm-size monomers evolve to oligomer of several hundred nanometers and reaches the fibrillar state forming plaques of up to a few tens of micrometers in size.

The researchers clearly discerned the different Aβ stages using THz near-field conductance measurements. This technique measures the energy absorbed by molecules at an energy band of around 1-10 meV (or 0.2-2.4 THz), and it is considered an effective technique for investigating the transformation of biological macromolecules without generating heat. The scientists measured how Aβ proteins in the solution are disturbed by incident THz radiation and noticed that the results were correlated with the form of the Aβ proteins: monomer, oligomer and fibril. Then, they derived the optical conductance, which decreases with the evolving fibrillization states and increases with the elevating molar concentrations.

Since the progressive stages of the disease can be differentiated simply with this technique, the team derived a dementia quotient (DQ) from the optical conductance, using the so-called Drude?Smith model. A DQ value of around one indicates that Aβ is in a fibril state, around 0.64 an oligomeric state, and nearly zero is at a monomeric state.

"We believe that our result gives us a significant paradigm shift in the Alzheimer's disease research field, since the dementia quotient is clearly identified from the label-free conductance measurement of different Aβ protein structural states," says Chaejeong Heo, one of the leading authors of this study. CINAP Director, Young Hee Lee adds "This index can be useful for early detection of toxic Aβ protein aggregation and fibrillization observed in Alzheimer's disease."

A new form of magnetic brain stimulation rapidly relieved symptoms of severe depression in 90% of participants in a small study conducted by researchers at the Stanford University School of Medicine.

The researchers are conducting a larger, double-blinded trial in which half the participants are receiving fake treatment. The researchers are optimistic the second trial will prove to be similarly effective in treating people whose condition hasn't improved with medication, talk therapy or other forms of electromagnetic stimulation.

The treatment is called Stanford Accelerated Intelligent Neuromodulation Therapy, or SAINT. It is a form of transcranial magnetic stimulation, which is approved by the Food and Drug Administration for treatment of depression. The researchers reported that the therapy improves on current FDA-approved protocols by increasing the number of magnetic pulses, speeding up the pace of the treatment and targeting the pulses according to each individual's neurocircuitry.

Before undergoing the therapy, all 21 study participants were severely depressed, according to several diagnostic tests for depression. Afterward, 19 of them scored within the nondepressed range. Although all of the participants had suicidal thoughts before the therapy, none of them reported having suicidal thoughts after treatment. All 21 participants had previously not experienced improvements with medications, FDA-approved transcranial magnetic stimulation or electroconvulsive therapy.

The only side effects of the new therapy were fatigue and some discomfort during treatment, the study reported. The results will be published online April 6 in the American Journal of Psychiatry.

"There's never been a therapy for treatment-resistant depression that's broken 55% remission rates in open-label testing," said Nolan Williams, MD, assistant professor of psychiatry and behavioral sciences and a senior author of the study. "Electroconvulsive therapy is thought to be the gold standard, but it has only an average 48% remission rate in treatment-resistant depression. No one expected these kinds of results."

Calming the brain chatter

When Deirdre Lehman, 60, woke up the morning of June 30, 2018, she said she was hit by "a tsunami of darkness." Lehman had struggled with bipolar disorder all her adult life, but with medications and psychotherapy her mood had been stable for 15 years.

"There was a constant chattering in my brain: It was my own voice talking about depression, agony, hopelessness," she said. "I told my husband, 'I'm going down and I'm heading toward suicide.' There seemed to be no other option."

Lehman's psychiatrist had heard of the SAINT study and referred her to Stanford. After researchers pinpointed the spot in her brain that would benefit from stimulation, Lehman underwent the therapy.

"By the third round, the chatter started to ease," she said. "By lunch, I could look my husband in the eye. With each session, the chatter got less and less until it was completely quiet.

"That was the most peace there's been in my brain since I was 16 and started down the path to bipolar disorder."

In transcranial magnetic stimulation, electric currents from a magnetic coil placed on the scalp excite a region of the brain implicated in depression. The treatment, as approved by the FDA, requires six weeks of once-daily sessions. Only about half of patients who undergo this treatment improve, and only about a third experience remission from depression.

Stanford researchers hypothesized that some modifications to transcranial magnetic stimulation could improve its effectiveness. Studies had suggested that a stronger dose, of 1,800 pulses per session instead of 600, would be more effective. The researchers were cautiously optimistic of the safety of the treatment, as that dose of stimulation had been used without harm in other forms of brain stimulation for neurological disorders, such as Parkinson's disease.

Other studies suggested that accelerating the treatment would help relieve patients' depression more rapidly. With SAINT, study participants underwent 10 sessions per day of 10-minute treatments, with 50-minute breaks in between. After a day of therapy, Lehman's mood score indicated she was no longer depressed; it took up to five days for other participants. On average, three days of the therapy were enough for participants to have relief from depression.

"The less treatment-resistant participants are, the longer the treatment lasts," said postdoctoral scholar Eleanor Cole, PhD, a lead author of the study.

Strengthening a weak connection

The researchers also conjectured that targeting the stimulation more precisely would improve the treatment's effectiveness. In transcranial magnetic stimulation, the treatment is aimed at the location where most people's dorsolateral prefrontal cortex lies. This region regulates executive functions, such as selecting appropriate memories and inhibiting inappropriate responses.

For SAINT, the researchers used magnetic-resonance imaging of brain activity to locate not only the dorsolateral prefrontal cortex, but a particular subregion within it. They pinpointed the subregion in each participant that has a relationship with the subgenual cingulate, a part of brain that is overactive in people experiencing depression.

In people who are depressed, the connection between the two regions is weak, and the subgenual cingulate becomes overactive, said Keith Sudheimer, PhD, clinical assistant professor of psychiatry and a senior author of the study. Stimulating the subregion of the dorsolateral prefrontal cortex reduces activity in the subgenual cingulate, he said.

To test safety, the researchers evaluated the participants' cognitive function before and after treatment. They found no negative side effects; in fact, they discovered that the participants' ability to switch between mental tasks and to solve problems had improved -- a typical outcome for people who are no longer depressed.

One month after the therapy, 60% of participants were still in remission from depression. Follow-up studies are underway to determine the duration of the antidepressant effects.

The researchers plan to study the effectiveness of SAINT on other conditions, such as obsessive-compulsive disorder, addiction and autism spectrum disorders.

'Resilient and stable'

The depression Lehman woke up to almost two years ago was the worst episode she had ever experienced. Today, she said, she is happy and calm.

Since undergoing SAINT treatment, she has completed a bachelor's degree at the University of California-Santa Barbara; she had dropped out as a young woman when her bipolar symptoms overwhelmed her studies.

"I used to cry over the slightest thing," she said. "But when bad things happen now, I'm just resilient and stable. I'm in a much more peaceful state of mind, able to enjoy the positive things in life with the energy to get things done."

Black carbon (BC) measurements in Antarctica are still scarce, but necessary to understand the particle's effect in our climate, says Luciano Marquetto, a Ph.D. student from the Polar and Climatic Center, Federal University of Rio Grande do Sul, Brazil.

"Black carbon, or BC, commonly known as soot, is a particle originated from the incomplete combustion of fossil fuels and biomass burning that warms the atmosphere. When deposited in snow and ice, BC increases surface radiation absorption and can cause melt," explains Mr. Marquetto. "Some scientists say that BC is second only to CO2 in its warming effects on the climate, and studies have shown that BC concentrations have risen since the industrial revolution in several places of the world, including Greenland, the Himalayas, the Alps and even Antarctica."

But studying BC in Antarctica is logistically challenging, and only in the last decade the topic has gained more attention. "Antarctica is a vast continent, and there are regions with no BC data yet. As climatic and atmospheric models rely on field data, studying BC concentrations in Antarctic snow is essential to improve these models", adds Mr. Marquetto.

Mr. Marquetto was part of a team of Brazilian researchers led by Dr. Jefferson Cardia Simões (Polar and Climatic Center) who carried out a traverse in West Antarctica in the 2014/2015 austral summer. They travelled more than 1400 km, collecting several shallow snow cores and samples along the way to investigate the snow chemistry (and consequently the atmospheric chemistry) in the last 50 years or so. One of these shallow cores was analyzed for BC in cooperation with Dr. Susan Kaspari (Central Washington University, USA).

"We observed very low BC concentrations in snow, lower than in other works in the continent. Due to that, in the article published in Advances in Atmospheric Sciences we decided to focus on instrumental and methodological questions raised during the research that needed to be answered before going deeper into the environmental interpretation", Mr. Marquetto says.

"However, our ultimate goal is to better understand BC seasonal variability and overall concentrations to see what impact the particle has in Antarctic snow, as well as try to identify BC geographical sources. We are also interested in the BC size distribution in snow, as particle size affects the amount of solar radiation BC can absorb. Impacts in the atmosphere and in the cryosphere are possibly being under or overestimated due to simplified representations of BC particle size in climatic models", believes Mr. Marquetto.

"As for sectorial sources, we know biomass burning represents around 80% of all BC emitted to the atmosphere in the Southern Hemisphere, which means that the fires happening in Australia, New Zealand and South America ultimately leave a mark in Antarctic snow."

From early prenatal development through childhood, the prefrontal cortex of the human brain undergoes an avalanche of developmental activity. In some cases, it also contains seeds of neuropsychiatric illnesses such as autism spectrum disorder and schizophrenia, according to a new genetic analysis led by researchers at Yale University and the University of California-San Francisco (UCSF).

Previous studies have identified DNA variants linked to neuropsychiatric illnesses, but it has been unclear just when those variations might trigger functional changes in the dorsal lateral prefrontal cortex, a region closely linked to neuropsychiatric, cognitive, and emotional disorders. This new study, published April 7 in the journal Cell Reports, added a new dimension to prior research. The scientists also measured the amount of RNA, which provides a picture of overall gene activity, in 176 tissue samples across a variety of developmental stages to determine how and when DNA variants influence brain function.

"This is the first large cohort to profile DNA and RNA both in prenatal and postnatal human brain samples, making it an unprecedented resource for understanding how individual genetic differences might lead to functional differences," said Yale's Sirisha Pochareddy, an associate research scientist in neuroscience and co-lead author of the study.

Understanding how genetic variation and changes in function are linked will help scientists understand how alterations of brain development can lead to schizophrenia and autism later in life, said the authors of the study. Since the research tracked thousands of variants associated with thousands of genes across the entire genome, scientists can identify groups of genes that regulate distinct biological processes and study how they can lead to disease, they said.

"Human brain development is an incredibly complex and dynamic process, and any disruption along the way can have profound consequences on later brain function," said co-lead author Donna Werling, formerly of UCSF and now at the University of Wisconsin-Madison. "Interestingly, we found that some genetic variants have stronger effects on RNA expression before birth and other variants with strongest effects after birth."

Studying these age-specific effects can open more doors for learning about the mechanisms behind brain disorders, the authors said.

For infants as young as four months, a hug from a parent makes all the difference. A study appearing April 7 in the journal iScience examined heart rate responses in infants less than one year old during a hug and found that children as young as four months experience greater heart rate slowing during a hug than a hold--and during a hug from their parent as compared to a hug from a stranger. The researchers say that the study offers some of the first evidence that hugs play an important role in early bonding between parents and their children.

"Like most parents, we love to hug our children," says first author Sachine Yoshida (@sachine_yoshida) of Toho University in Tokyo, Japan. "We also know that children love to be hugged by their parents. But what surprised us as scientists is how little we know about hugging."

One question was whether a hug was really calming or whether any increase in pressure--for instance, from being held--could be soothing. To begin to explore this in the new study, Yoshida along with Hiromasa Funato (@HiromasaFunato) and their colleagues examined heart rate responses in infants less than one year during a hold, a hug, and a tight hug. They also looked at what happens when a female stranger did the hugging instead.

"The infants older than four months old showed a high increase ratio of heartbeat intervals during hugging by their parents than by female strangers," Yoshida said. "Parents also showed a high increase ratio of heartbeats intervals by hugging their infants. We found that both infants and parents come to relax by hugging."

The researchers report that parents and infants both showed an increase during a hug in what's known as the R-R interval (RRI) on an electrocardiogram. The R-R interval is the time between a particular waveform that measures electrical activity of the heart. The increased time indicates a slowed heart rate.

Infants younger than four months didn't show the same RRI increase during a hug, the researchers reported. But those young infants did show a slowed heart rate when a parent's hand put pressure on his or her back while being held, suggesting that they didn't make the same distinction as older infants between being held and being hugged

The researchers say that they had expected a hug would lead to obvious changes in an infant's behavior, turning a fussy mood into a good one, perhaps. But what surprised them was that the calming effects of a hug that they observed only could be detected on infants who were neither crying nor fussy. "Due to this inconspicuous feature, we think that the experimental data indicating the relaxing effect of a parent-infant hug had been a missing piece for a while, even though there was much situational evidence," Funato says.

"Your baby loves to be hugged and loves how you hug your baby," Yoshida adds. "Even though infants cannot speak, they recognize their parents through various parenting methods, including hugging, after four months old at latest. We hope that knowing how your baby feels while being hugged help ease the physical and psychological workload of taking care of infants too young to speak."

Adults talk to babies differently from how we would speak to other adults. Compared to how adults speak, speech directed at babies tends to have a higher, more varied pitch, greater positive affectation, it is slower and involves shorter phrases. The characteristics of this speech targeting babies has been studied extensively and it has been found that it is a common feature of different cultures.

Moreover, several studies have shown that already in the first months of life, babies not only interpret gaze, speech or gestures when we communicate with them, but also understand that other people use them when they communicate.

While previous research has established that babies are sensitive to being spoken to as infants, until now it was not known what expectations children have, whether they expect special speech to be directed at them, and in general for all babies like them, or if they expect adults to talk to each other as adults. A study aimed to find out if babies gain awareness of this conduct and if they can distinguish when someone is addressing them or other adults appropriately.

Animated videos for babies from 12 to 15 months

A study published in the advanced edition of the journal Cognition presents the results of a series of experiments carried out on Spanish and Turkish babies aged 12 to 15 months. The children watched animated videos with big and small geometric figures simulating adults and children talking to each other. The study was carried out by Núria Sebastián Gallés, head of the Speech Acquisition and Perception (SAP) research group at the Center for Brain and Cognition (CBC) of the Department of Information and Communication Technologies (DTIC) at UPF, together with Gaye Soley, a researcher with the Department of Psychology at Bo?aziçi University in Istanbul (Turkey).

In two of the conditions (Figure 2 a and b of the work), the respective figures communicated congruently, that is, the adult figure addressed the child figure using IDS - infant-directed speech, or another adult using ADS - adult-directed speech. In the other conditions (Figure 2 c and d of the work) this pattern is altered incongruently: the adult spoke to another adult as if the latter were a child, or spoke to the child as if it were an adult. The results showed that both Spanish and Turkish infants aged between 12 and 15 months watched for longer when presented with incongruent than with congruent events. This increased gaze time is interpreted as a reaction of surprise at an unexpected situation.

In the last experiment, the stimuli were identical to those of experiments 1 and 2, but the characters no longer "looked" at each other (Figure 4). In this situation, the babies did not show any differences in their gaze time between congruent and incongruent conditions. These results indicate that babies interpret that the figures are not communicating with each other as they do not keep eye contact.

These findings raise important questions about the mechanisms whereby infants' expectations are formed. "Our results show that infants have formed expectations not only about the recipients of infant-directed speech, but also the recipients of adult-directed speech, suggesting that their expectations are not formed based only on their own experiences, but also on their observations of interactions between adults", Soley and Sebastián claim.

Babies may develop these expectations as they are exposed to different registers of speech when others around them communicate with babies and adults. If so, infants' expectations may be different depending on how the adults of their environments produce speech. This could be studied and extended to other forms of communication such as gestures or actions.

Infants' expectations regarding recipients of speech, infants or adults, point to the social importance of these different styles of communication and suggest that early on, the acoustic signs associated with these different registers of speech are accessible to babies and guide their social expectations.