Earth

When modeling the El Niño-Southern Oscillation (ENSO) ocean-climate cycle, adding satellite sea surface salinity -- or saltiness -- data significantly improves model accuracy, according to a new NASA study.

ENSO is an irregular cycle of warm and cold climate events called El Niño and La Niña. In normal years, strong easterly trade winds blow from the Americas toward southeast Asia, but in an El Niño year, those winds are reduced and sometimes even reversed. Warm water that was "piled up" in the western Pacific flows back toward the Americas, changing atmospheric pressure and moisture to produce droughts in Asia and more frequent storms and floods in the Americas. The reverse pattern is called a La Niña, in which the ocean in the eastern Pacific is cooler than normal.

The team used NASA's Global Modelling and Assimilation Office (GMAO) Sub-seasonal-To-Seasonal (S2S) coupled ocean/atmosphere forecasting system (GEOS-S2S-2) to model three past ENSO events: The strong 2015 El Niño, the 2017 La Niña and the weak 2018 El Niño.

Pulling from NASA's Soil Moisture Active Passive (SMAP) mission, the past NASA-CONAE (Argentinian Space Agency) Aquarius mission and the European Space Agency's Soil Moisture Ocean Salinity (SMOS) mission, they compared the forecast model's accuracy for each of the three events with and without assimilating SSS data into the models' initialization. In other words: One model run's initial conditions included SSS data, and the other did not.

Adding assimilation of SSS data to the GEOS model helped it to depict the depth and density of the ocean's top layer more accurately, which led to better representations of large-scale circulation in response to ENSO. As a result, the models' predictions for the three case studies more closely reflected actual observations, compared to what forecasting models predicted at the time.

"In our three case studies, we examined different phases of ENSO," said Eric Hackert, a research scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland and the study's lead author. "For the big El Niño in 2015, assimilating the salinity data damped the signal -- our original model was overestimating the amplitude of the event. For the other two ENSO events, the forecasts originally predicted the wrong sign: For example, in 2017, the model without salinity data forecasted an El Niño, while the real ocean produced a La Niña. However, for each case we examined, adding satellite salinity to the initialization improved the forecasts."

The study is one of the first to incorporate SSS data into forecast initialization for a global coupled model of interactions between the ocean, atmosphere, land, aerosols and sea ice. GEOS and other models used to help predict ENSO events do not typically include SSS. However, ocean surface salinity plays an important role in ocean currents, evaporation and interaction with the atmosphere, and heat transfer from the tropics to the poles. Colder, saltier water is denser and heavier than warmer, fresher water, and the large-scale temperature and precipitation shifts of ENSO events change ocean circulation and interactions between the water and atmosphere.

Both phases of the ENSO cycle affect ecosystems, economies, human health, and wildfire risk -- making ENSO forecasts vital for many people around the world, Hackert said.

"For example, forecasts and observations gave a strong indication that there would be a big El Niño in 1997, which would lead to drought in northeast Brazil," he said. "This allowed the government of Brazil to issue a statement to substistence farmers, encouraging them to plant drought-resistant corn instead of high-yield varieties. In this case, good ENSO forecasts along with government action may have saved many lives. This is just one example of many socio-economic benefits for extending useful El Niño predictions."

Including satellite SSS data also makes models useful for longer periods -- accurate ENSO forecasts without salinity data only extend out 4 months, while those with SSS data cover 7 months, Hackert said.

"Rather than having one season of confidence in your forecast, you have two seasons," Hackert said. "If your growing season is six months down the line, a longer quality forecast gives you an improved understanding of whether you need to plant high-yield or drought-resistant varieties. Another example would be that you have plenty of time to fix your roof if you live in Southern California (since El Niño typically brings rainy conditions to the southern US)."

Having access to an ongoing record of satellite SSS data is essential for making forecasts accurate and reliable, Hackert said.

"In current forecast systems, satellite and ocean observations are optimally combined using models and data assimilation techniques to help define the state of the ocean," he said. "This study shows that adding satellite SSS to the suite of current observations helps to characterize the near-surface ocean state, leading to improved seasonal forecasts. We recommend that other forecast model systems around the world adopt SSS into their systems."

PORTLAND, Ore. - Scientists have developed a precise, nanotechnology-based treatment to alleviate the pain and fertility problems associated with endometriosis, a common gynecological condition in women of childbearing age.

Research led by Oleh Taratula of the Oregon State University College of Pharmacy and Ov Slayden of the Oregon National Primate Research Center at Oregon Health & Science University used photo-responsive nanoparticles loaded with dye to find and remove the lesions associated with the disorder.

Findings were published today in the journal Small.

The endometrium is the innermost layer of the uterus, and endometriosis occurs when endometrium-like tissue forms lesions outside of the uterine cavity - usually involving the ovaries, the fallopian tubes and the tissue lining the pelvis.

On rare occasions, endometrial tissue may spread beyond the pelvic organs.

Roughly 10% of childbearing-age women will experience endometriosis, and 35% to 50% of women with pelvic pain and or infertility suffer from the disorder.

There's no cure, although surgical removal of the lesions can improve fertility. The downside, however, is that the lesions come back about half the time, and more than one-quarter of endometriosis surgery patients need three or more operations because it's hard to find all of the diseased tissue that needs to be removed.

Taratula and Slayden, in a collaboration that also included OSU's Carlson College of Veterinary Medicine, used tiny - less than 100 nanometers in size - polymeric materials packed with a dye that can generate both a fluorescence signal and cell-killing heat under near-infrared light.

For doctors, that means it can be both an imaging tool and a lesion-removal technique.

"We built our strong team to combine expertise in both nanomedicine and endometriosis," said Olena Taratula, also a researcher with the College of Pharmacy. "This is a devastating disease, and we developed and evaluated the photo-responsive nanoagent to detect and eliminate unwanted endometrial tissue with photothermal ablation."

That means injecting the dye-loaded nanoparticles into the body, where they fluoresce to show where the lesions are, and also kil them with heat because the particles soar to 115 degrees Fahrenheit upon exposure to near-infrared light.

"The challenge has been to find the right type of nanoparticles," Oleh Taratula said. "Ones that can predominantly accumulate in endometriotic lesions without toxic effect on the body, while preserving their imaging and heating properties."

By using a clinically relevant animal model of endometriosis developed by Slayden's group at the primate center, the scientists showed that the nanoparticles constructed by the Taratula group can efficiently accumulate in endometrial tissue 24 hours after being administered. Slayden is a professor of reproductive and developmental sciences at the Oregon National Primate Research Center and a professor of obstetrics and gynecology and molecular and cellular biosciences at the OHSU School of Medicine.

"The heat is produced under near-infrared laser light that is harmless to tissue without the presence of the nanoparticles," Oleh Taratula said. "The generated heat eradicates the endometrial lesions completely within a day or two. Dr. Slayden and I built this team years ago to help surgeons to better visualize and treat endometriosis lesions, and we're getting close."

To advance the technology to human clinical trials, future studies are needed to validate the treatment approach in animals that develop endometriosis similar to how it presents in humans, he added. The research team has received a grant from the National Institutes of Health to evaluate the efficiency of the nanoparticles in macaques with endometriotic lesions.

"We believe that our developed strategy can eventually shift the current paradigm for endometriosis detection and treatment," Oleh Taratula said. "In general, nanomedicine has barely been explored for imaging and treatment of endometriosis. Our results validate that some fundamental principles of cancer nanomedicine can potentially be used for the development of novel nanoparticle-based strategies for treatment and imaging of endometriosis."

In the wake of the novel coronavirus pandemic, Texas A&M University chemist Wenshe Ray Liu and his research team have focused their lab solely on searching for drugs to treat COVID-19.

The Liu group was the first to identify the antiviral drug remdesivir as a viable medicine to treat COVID-19 in a research study published in late January. The drug was originally developed in response to the 2014 Ebola pandemic.

As a chemical biologist specializing in medicinal chemistry, Liu's primary research target is cancer. But the lockdown of Wuhan and the first two diagnosed cases in the U.S. prompted him to refocus his lab on coronavirus.

"The motivation that drove us was the rush against time to find alternative medicines that might be put in use to fight against the virus when it spread to the U.S," Liu said.

The researchers are working to develop drugs that can prevent SARS-CoV-2 - the virus that causes COVID-19 - and other coronaviruses from replicating once inside human cells. They're also exploring how to counteract the effect of the viruses in human plasma.

Liu said his group has made significant progress in a very short time toward their ultimate goal: to push a COVID-19 drug candidate to preclinical trials and clinical testing before the pandemic subsides.

"There is sufficient scientific knowledge for this group of viruses, and we will be able to find cures," he said.

Remdesivir is being tested in at least five large-scale clinical trials around the world and also has been delivered to some patients, including the first known U.S. case confirmed Jan. 21 in Washington. That patient recovered after compassionate use of remdesivir.

While Liu said he remains convinced it's the right treatment, he cautioned that success shouldn't be viewed as a one-shot approach, given such a swift-moving target as COVID-19.

"Remdesivir is still the best and probably the only option to target the virus directly in patients," he said.

With the U.S. clinical trial set to finish this week, Liu is optimistic that the final results released next week will speak for themselves. However, with remdesivir poised to be the only approved drug to treat COVID-19, its large-scale use will occur, and some drug-resistant virus strains will evolve.

"At this stage, the scientific community needs to prepare for the worst and work to bring other treatment options to the forefront," he said, adding that while there have been positive results from tests of hydroxychloroquinine, additional options are needed.

When it comes to viral mutations and reports that multiple strains of the virus exist, Liu deferred to clinicians, but acknowledged that it has become more virulent.

"The infectivity of the original strain shown in Wuhan was not as high as what we have observed for the current strain in the U.S.," he said.

The first published data from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease (A4) study supports the hypothesis that higher levels of the amyloid protein in the brain represent an early stage of Alzheimer's disease. Results of an analysis of participant screening data for the study, published April 6 in JAMA Neurology, also show that amyloid burden in clinically normal older adults is associated with a family history of disease, lower cognitive test scores, and reports of declines in daily cognitive function. Major funding was provided by the National Institute on Aging (NIA), part of the National Institutes of Health; all data is now freely available to the broader research community.

With completion expected in late 2022, the A4 study is an ongoing prevention trial launched in 2014 to test whether the drug solanezumab, a monoclonal antibody, could slow cognitive decline associated with elevated brain amyloid if started before clinical symptoms appear. Amyloid, long considered a hallmark of Alzheimer's disease, has been the target of therapies in clinical trials in people who already show symptoms of the disease.

"A major issue for amyloid-targeting Alzheimer's disease clinical trials, and one that is being addressed with the A4 study, is that previous trials may have been intervening too late in the disease process to be effective," said NIA Director, Richard J. Hodes, M.D. "A4 is pioneering in the field because it targets amyloid accumulation in older adults at risk for developing dementia before the onset of symptoms."

The A4 study team was looking for cognitively normal participants with high levels of amyloid. They started by pre-screening more than 15,000 people who expressed interest in the trial. Of those 15,000, the researchers brought in 6,763 clinical trial volunteers for cognitive testing, clinical assessments and genotyping. After excluding 2,277 participants for cognitive and/or medical reasons, researchers used amyloid positron emission tomography (PET) imaging with 4,486 participants to measure amyloid accumulation in the brain. The PET imaging revealed 1,323 with elevated amyloid levels who were eligible to continue in the A4 study.

"In 2014, A4 was a first-of-its-kind study because it used amyloid PET to identify cognitively normal people with high levels of brain amyloid," said Laurie Ryan, Ph.D., chief of the Dementias of Aging branch in NIA's Division of Neuroscience. "Before the availability of amyloid PET, other amyloid-targeting clinical trials may have been testing therapies in some people who didn't have amyloid."

Writing for the A4 study team, lead author Reisa A. Sperling, M.D., at Brigham and Women's Hospital and Harvard Medical School, Boston, noted in the paper that the screening data of all 4,486 participants who had PET imaging is now available to the research community. This new data will help improve efficiency of screening and enrollment of other trials designed to prevent Alzheimer's in people without symptoms.

"A4 demonstrates that prevention trials can enroll high risk individuals -- people with biomarkers for Alzheimer's who are cognitively normal," said Ryan, adding, "Ultimately, precision medicine approaches will be essential."

"Alzheimer's disease is never going to have a one-size-fits-all treatment," she said. "We're likely to need different treatments, even combinations of therapies, for different individuals based on their risk factors."

NIA's diverse Alzheimer's disease and related dementias research portfolio includes about 230 clinical trials. Of these, more than 100 are focused on non-pharmacological interventions, including but not limited to diet, exercise and cognitive training. Of the current 46 pharmacological trials supported by NIA, most investigate targets other than amyloid, such as neuroprotection and inflammation.

Patients with colon cancer, but no distant metastases yet, can benefit from a short course of immunotherapy while waiting for their surgery, as it can cause tumours to shrink substantially or clear up in a very short time. The patient's own immune cells have cleared away the cancer cells. This is the finding of a NICHE study by the Netherlands Cancer Institute, an innovatory phase II clinical trial. In patients with a specific subtype of colon cancer (MSI) 100% of the patients benefited from the therapy. In the other half (with MSS type) this was 25%.

Medical oncologist Myriam Chalabi and her fellow researchers will publish these results on Monday 6 April in the journal Nature Medicine.

Neoadjuvant immunotherapy

Immunotherapy prior to surgery is referred to as 'neoadjuvant immunotherapy'. The aim is to prevent the cancer returning or metastasising and, in the case of large tumours, to make surgery easier. The main idea is to familiarise the immune system with all the tumour variations before the tumour is removed, enabling the system to respond better. Colon cancer is the second type of cancer, after melanoma, for which researchers at the Netherlands Cancer Institute have shown the effect of neoadjuvant immunotherapy in a scientific journal. Studies on other types of tumours are still in progress.

100% response rate in patients with the 'microsatellite-instable' subtype

Forty patients with two colon cancer subtypes took part in the NICHE study. Twenty of them had the microsatellite-instable (MSI) subtype, which means that the tumour is highly susceptible to mutation, resulting in hundreds and hundreds of mutations. Of all patients with non-metastasised colon cancer, 15% have this type, and the therapy was effective in all 20 patients. 'A good response rate was on the cards in this group', says project manager Myriam Chalabi. 'But a 100% rate is unprecedented. You don't dare hope it will be that good.'

The patients underwent surgery about four weeks after the first intravenous administration. During that short period the vast majority of these tumours had cleared up completely or almost completely. 'We could see clearly where the tumour had been, but the patient's own immune cells had cleared away the cancer cells.'

Previous research had already shown that immunotherapy is effective against advanced metastasised colon cancer in this subgroup. There is a good scientific explanation: the more new mutations there are, the more non-self the tumour is, causing the immune system to spring into action.

25% response rate in patients with the 'microsatellite-stable' subtype of colon cancer

The remaining twenty patients in the NICHE study had microsatellite-stable (MSS) tumours. Tumours of this type, conversely, are known not to respond well to immunotherapy. To their great surprise, the researchers found that 25% of this group of patients also responded well. Given that 85% of all patients with non-metastasised colon cancer have this type, this, too, is a hopeful outcome.

The researchers looked for an explanation of this surprisingly high response rate in the MSS group in the lab. To begin with it was not easy. 'We looked at all the usual suspects, but they weren't the cause', says Chalabi. 'We didn't see the same predictive factors as in melanoma, for instance. But in the end we did find a new biomarker. If that proves to be predictive in follow-up studies, it could provide a simple way of identifying patients with MSS tumours who could benefit from immunotherapy.'

A lot more to learn in the lab

An important added advantage of neoadjuvant studies is that they enable the precise effects of immunotherapy on excised cancerous tissue to be determined for individual patients. In that sense too, neoadjuvant therapy is making for a revolution in cancer research, with lab work and clinical practice becoming more integrated.

Working together with surgeons

Pioneering neoadjuvant drug studies like NICHE also have a major impact on the work of oncology surgeons. The studies depend on their trust: are surgeons willing to accept the waiting and the uncertainty? Myriam Chalabi notes: 'Our surgeons were very enthusiastic right from the start, otherwise we could never have carried out the trial.' The first aim of the NICHE study was therefore to show that operations could take place safely and according to schedule and that there would be no more post-operative complications than expected - which did indeed turn out to be the case.

Can surgery be dispensed with?

The researchers, like the patients, are very happy with the results of the NICHE study. Chalabi says: 'Large tumours shrinking or clearing up completely within four weeks on average is a fantastic, unprecedented result. We've never seen a 100% response rate before.' The question - as raised by some patients in the trial - is, if the tumour has gone, could surgery perhaps be dispensed with altogether?

That would be too early, warns Chalabi, as 'even if we find the tumour has gone when we operate, we cannot know in advance who will have a complete response, not even with the aid of scans.' Researchers therefore need to find an answer to this question: how we can know as far as possible before surgery whether patients will have a complete response? 'It won't be easy, but we're busy working on it.'

What is the likelihood that a patient will still develop metastases once the tumour has cleared up completely or almost completely? 'We think the risk is very low', says Chalabi. 'We've found that with melanoma. But first we need to treat patients and monitor them for years before we can answer that question.'

Follow-up study

The NICHE study will therefore continue and the number of patients will be stepped up. They will be monitored for at least three years to see whether they remain disease-free. 'Only then can the new therapy be considered as a standard treatment', says Chalabi. At the same time a lot of new research will be going on in the lab using tumour material from these patients. The researchers will be using brand new techniques: advanced medical imaging, for instance, and what are known as 'liquid biopsies' to look for traces of tumour DNA in the blood.

Global climate change will affect fish sizes in unpredictable ways and, consequently, impact complex food webs in our oceans, a new IMAS-led study has shown.

Led by IMAS and Centre for Marine Socioecology scientist Dr Asta Audzijonyte and published in the journal Nature Ecology and Evolution, the study analysed three decades of data from 30 000 surveys of rocky and coral reefs around Australia.

Dr Audzijonyte said the study confirmed that changes in water temperature were responsible for driving changes in average sizes of fish species across time and spatial scales.

"Cold blooded animals, especially fish, have long been noted to grow to a smaller size when raised in warmer temperatures in an aquarium," Dr Audzijonyte said.

"If fish grow to smaller sizes in warmer aquaria, it is only natural to expect that global warming will also lead to shrinkage of adult fish size.

"However, average fish body size in wild populations are affected by growth, mortality, recruitment as well as interactions with other organisms and their environment simultaneously and it is unclear how all of these factors are affected by temperature."

The researchers were surprised to find that while temperature has a significant impact, it caused different fish species to react differently.

In some the average fish body size got smaller as predicted (around 55% of species) but in others it increased (around 45%).

In general - but not universally - larger species tended to get even bigger in warmer waters, while smaller species tended to get smaller.

Tropical species were more likely to be smaller at the warm end of their distribution ranges.

Most importantly, the species that were smaller at the warmer edges of their habitat ranges were also more likely to get on average smaller with global warming.

"At Tasmanian survey locations, where some of the fastest rates of warming were observed, up to 66% of species showed clear changes in body size."

"As well as happening quite quickly, some of the size changes can also be surprisingly large.

"For example, the change in a median-length temperate fish corresponds to around 12% of its body mass for each 1oC of warming.

"At the current rate of warming, in 40 years this would result in around a 40% change in body length, either increasing or decreasing depending on the species," she said.

Dr Audzijonyte said the varying responses of species to warming would have implications for food webs and ecosystems, including their stability and resilience to other external stressors, such as fishing, coastal pollution and a range of different climate change impacts.

The study was made possible through collaboration between University of Tasmania scientists and government managers across Australia, and by the efforts of over 100 volunteer Reef Life Survey divers, who have undertaken regular surveys at over 1000 sites around the continent.

In October 2018, the Tunisian Ro-Ro passenger ship "Ulysse" rammed into the hull of the Cyprus-flagged container ship "Virginia", which was anchored in international waters off the northern tip of Corsica, an area known for its pristine waters and beaches. Bunker fuel from Virginia leaked out of her tanks through a breach several meters long, threatening the marine environment and coastal areas. 530 m3 of oil were released, and in 36 hours the slick had lengthened to cover approximately 35 km.

Predicting the drift of oil slicks on water surfaces and in coastal zones is fundamental for responding to spill events and to mitigate their impacts on the environment, allowing for a more efficient use of emergency response resources.

A recently published scientific paper tells about the collaboration that was formed for this purpose, between the researchers of the CMCC Foundation - Euro-Mediterranean Center on Climate Change and REMPEC, the Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea, based in Malta, right after the collision of Ulysse with Virginia.

"Thanks to a joint effort involving efficient and timely exchange of information, we received observational data from REMPEC and used these real observations as the starting point for our model in order to calculate the forecast", explains Svitlana Liubartseva, researcher at the CMCC Foundation and first author of the study. "We worked day and night, and provided REMPEC with 5 forecast bulletins during the oil spill tracking and recovery operations."

Forecast of currents, wind, waves and sea surface temperatures are critical for predicting the spread and fate of oil. The study is focused on the ability to realistically predict the times and places where oil reaches coastlines thanks to the oceanographic model MEDSLIK-II, developed by CMCC Foundation. The model results were verified by comparing available observational data.

"Using the oceanographic and atmospheric dataset provided by the Copernicus Marine Environment Monitoring Service (CMEMS) and the European Centre for Medium-Range Weather Forecasts (ECMWF) we produced forecasts of the oil drift. The CMEMS output has a high resolution of about 4 km, that allowed us to produce a rather good quality of prediction of when and where the oil reached the beaches", specifies Dr. Liubartseva.

For the first 16 days after the accident, the model was able to generate reliable predictions, forecasting the oil movements at least 7 days in advance. Researchers were able to predict almost precisely the place and time where the oil would reach the coast for the first time. After more than 9 days drifting at sea, it landed near Saint-Tropez (France). Due to a lack of observational data in the long run there was a deterioration in the model solution, as the oil drifted for about one month. Nevertheless, the research demonstrates that the CMCC model facilitates the use and optimization of anti-pollution resource deployment and increases coastal preparedness.

CMCC researchers are now at work to further improve the predictability of oil spill drift and transformation. On the one hand, there is the need to improve the resolution of the models, making their grid finer and finer, which will involve studying more oil spill events to get better predictions.

Marine microorganisms, such as bacteria and so-called protists, form a large part of the biomass in the oceans. Protists are a group of unicellular microorganisms that have a solid cell nucleus and are therefore different from bacteria. Many protists are part of the phytoplankton and as such, they drive important global processes. They perform photosynthesis and thus play an important role in removing CO2 from the atmosphere. They also form the basis of the food web by which marine fisheries are fueled. Yet little is known about how these microorganisms function. This is largely due to the fact that for a long time it was not possible to genetically modify key species of phytoplankton. However, this is precisely the methodology for studying the functioning of proteins that control many essential processes in organisms. Questions like 'How do fluctuations in phytoplankton growth occur?' or 'What underlies how different algae respond to seasonal changes in the ocean?' could be answered in this way.

In order to get to the bottom of these questions the Gordon and Betty Moore Foundation established a 'high-speed' international collaborative initiative for developing genetic systems in marine eukaryotic organisms. The study synthesis published today in Nature Methods brings together the results of scientists from 53 institutions and 14 countries. It was co-led by Alexandra Z. Worden (GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany) alongside Julius Lukeš (Institute of Parasitology, Czech Academy of Science, Czech Republic) and Thomas Mock (University of East Anglia, UK).

Together, the international collaboration members worked to develop new ways of studying the individual proteins of marine protists. "The methods to analyze the function of individual proteins from key algal groups provide the scientific community with tools to carry out comparable investigations - that connect to identifying factors that allow algae to thrive and to respond to environmental change", says Professor Worden.

In the publication, Worden's team presents manipulation protocols for the widespread alga Micromonas. This tiny cell is nearly all chloroplast, the organelle where photosynthesis occurs. It was first discovered in the 1950s when it was shown to be highly abundant in the English Channel - and is now known for its worldwide distribution from pole to pole.

The concept behind the new methods is based on genetic transformation. This means that foreign DNA can be used to make proteins in an organism or that a certain gene in the organism can be switched off or removed. In many organisms, certain conditions have to be met for this transformation to occur. In order to induce it artificially, precise protocols must be followed. For many key species of marine protists like Micromonas, however, such protocols were not available - until today's publication. During the project, the team developed procedures that successfully transformed 13 diverse marine protists, enabling a breadth of future studies on their ecology and evolution.

"The new findings will allow us to understand the mechanisms algae use to respond to changes in the environment. This concerns understanding seasonal fluctuations due to a natural, annual rhythm, as well as transitions related to climate change", adds Worden.

We're familiar with how climate change is impacting the ocean's biology, from bleaching events that cause coral die-offs to algae blooms that choke coastal marine ecosystems, but it's becoming clear that a warming planet is also impacting the physics of ocean circulation.

A team of scientists from the University of British Columbia, the Bermuda Institute of Ocean Sciences (BIOS), the French Institute for Ocean Science at the University of Brest, and the University of Southampton recently published the results of an analysis of North Atlantic Ocean water masses in the journal Nature Climate Change.

"The oceans play a vital role in buffering the Earth from climate change by absorbing carbon dioxide and heat at the surface and transporting it in the deep ocean, where it is trapped for long periods," said Sam Stevens, doctoral candidate at the University of British Columbia and lead author on the study. "Studying changes in the structure of the world's oceans can provide us with vital insight into this process and how the ocean is responding to climate change."

One particular layer in the North Atlantic Ocean, a water mass called the North Atlantic Subtropical Mode Water (or STMW), is very efficient at drawing carbon dioxide out of the atmosphere. It represents around 20% of the entire carbon dioxide uptake in the mid-latitude North Atlantic and is an important reservoir of nutrients for phytoplankton--the base of the marine food chain--at the surface of the ocean.

Using data from two of the world's longest-running open-ocean research programs--the Bermuda Atlantic Time-series Study (BATS) Program and Hydrostation 'S'--the team found that as much as 93% of STMW has been lost in the past decade. This loss is coupled with a significant warming of the STMW (0.5 to 0.71 degrees Celsius or 0.9 to 1.3 degrees Fahrenheit), culminating in the weakest, warmest STMW layer ever recorded.

"Although some STMW loss is expected due to the prevailing atmospheric conditions of the past decade, these conditions do not explain the magnitude of loss that we have recorded," said Professor Nick Bates, BIOS senior scientist and principal investigator of the BATS Program. "We find that the loss is correlated with different climate change indicators, such as increased surface ocean heat content, suggesting that ocean warming may have played a role in the reduced STMW formation of the past decade."

These findings outline a worrying relationship where ocean warming is restricting STMW formation and changing the anatomy of the North Atlantic, making it a less efficient sink for heat and carbon dioxide.

"This is a good example of how human activities are impacting natural cycles in the ocean," said Stevens, who was previously a BATS research technician from 2014 through 2017 before beginning his doctoral work, which leverages the work he did with BATS/BIOS.

Lead-based perovskites are very promising materials for the production of solar panels. They efficiently turn light into electricity but they also present some major drawbacks: the most efficient materials are not very stable, while lead is a toxic element. University of Groningen scientists are studying alternatives to lead-based perovskites. Two factors that significantly affect the efficiency of these solar cells are the ability to form thin films and the structure of the materials in the solar cells. Therefore, it is very important to investigate in situ how lead-free perovskite crystals form and how the crystal structure affects the functioning of the solar cells. The results of the study were published in the journal Advanced Functional Materials on 31 March.

Photovoltaic cells that are based on hybrid perovskites were first introduced in 2009 and rapidly became almost as efficient as standard silicon solar cells. These materials have a very distinctive crystal structure, known as the perovskite structure. In an idealized cubic unit cell, anions form an octahedron around a central cation, while the corners of the cube are occupied by other, larger cations. Different ions can be used to create different perovskites.

Spin coating

The best results in solar cells have been obtained using perovskites with lead as the central cation. As this metal is toxic, tin-based alternatives have been developed, for example, formamidinium tin iodide (FASnI3). This is a promising material; however, it lacks the stability of some of the lead-based materials. Attempts have been made to mix the 3D FASnI3 crystals with layered materials, containing the organic cation phenylethylammonium (PEA). 'My colleague, Professor Maria Loi, and her research team showed that adding a small amount of this PEA produces a more stable and efficient material,' says Assistant Professor Giuseppe Portale. 'However, adding a lot of it reduces the photovoltaic efficiency.'

That is where Portale comes in. Perovskites have been studied for a long time by Professor of Photophysics and Optoelectronics Maria Loi, while Portale developed an X-ray diffraction technique that allows him to study the rapid formation of thin films in real-time during spin-coating from solution. On a laboratory scale, the perovskite films are generally made by spin coating, a process in which a precursor solution is delivered onto a fast-spinning substrate. Crystals grow as the solvent evaporates. At the beamline BM26B-DUBBLE at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, Portale investigated what happens during the tin-perovskite film formation.

Interface

'Our initial idea, which was based on ex situ investigations, was that the oriented crystals grow from the substrate surface upwards,' Portale explains. However, the in situ results showed the opposite: crystals start to grow at the air/solution interface. During his experiments, he used 3D FASnI3 with the addition of different amounts of the 2D PEASnI4. In the pure 3D perovskite, crystals started to form at the surface but also in the bulk of the solution. However, adding a small amount of the 2D material suppressed bulk crystallization and the crystals only grew from the interface.

'PEA molecules play an active role in the precursor solution of the perovskites, stabilizing the growth of oriented 3D-like crystals through coordination at the crystal's edges. Moreover, PEA molecules prevent nucleation in the bulk phase, so crystal growth only takes place at the air/solvent interface,' Portale explains. The resulting films are composed of aligned 3D-like perovskite crystals and a minimal amount of 2D-like perovskite, located at the bottom of the film. The addition of low concentrations of the 2D material produces a stable and efficient photovoltaic material, while the efficiency drops dramatically at high concentrations of this 2D material.

Insulator

The experiments by Portale and Loi can explain this observation: 'The 2D-like perovskite is located at the substrate/film interface. Increasing the content of the 2D material to above a certain amount causes the formation of an extended 2D-like organic layer that acts as an insulator, with detrimental effect for the device's efficiency.' The conclusion of the study is that the formation of this insulating layer must be prevented to achieve a highly efficient and stable tin-based perovskite. 'The next step is to realize this, for example by playing with solvents, temperature or specific perovskite/substrate interactions that can break up the formation of this thick insulating layer.'

Simple Science Summary

Just over ten years ago, scientists discovered a new, promising material that could convert light into electricity: metal-halide perovskite. The first solar cell perovskites contained lead, which is toxic. Soon, perovskites were developed that were based on tin, but these were not very stable. A few years ago, scientists at the University of Groningen demonstrated that adding another type of perovskite - one that forms two-dimensional layers instead of three-dimensional crystals - increased the stability; however, it reduced efficiency. University of Groningen scientists have now 'watched' how thin films of tin-based perovskite crystals grow. They discovered that in mixtures of 3D and 2D perovskites, the 2D component helps to orient the 3D-like crystals but, at the same time, the 2D perovskite forms an insulating layer that is in contact with the substrate. By breaking up this insulating layer, it should be possible to create more efficient and stable tin-based perovskite solar panels.

TROY, N.Y. -- From Steve Jobs to Mark Zuckerberg, the stories of prosperous, young innovators drive the American economic narrative. However, the truth is that older business entrepreneurs may be just as well suited to success. And older women are far more successful at launching a business than their younger counterparts.

Those are among the findings reached by Hao Zhao, an associate professor of management at the Lally School of Management at Rensselaer Polytechnic Institute, in research recently published online in the Journal of Business Venturing.

"Correcting people's negative stereotypes about older entrepreneurs, and encouraging people at later life stages to engage in entrepreneurship, is important," Zhao said. "The United States has an increasing population of older adults that have skills and knowledge valuable to society. This study helps to illustrate their strengths."

Zhao and his co-authors conducted a meta-analysis based on 102 independent samples and determined that the rate of success for people who launch a business in their 20s is the same as for those who become entrepreneurs in their 50s. According to Zhao, this suggests that, while younger entrepreneurs are generally more adapt at inventing new technology and making bold moves, their older counterparts have more wisdom, financial capital, and business connections.

Zhao found that older entrepreneurs have slightly higher satisfaction levels and greater financial success than younger entrepreneurs. Their only disadvantage is slightly lower growth rates, an artifact of their companies tending to be larger in size.

Additionally, the study showed that age has a positive and significant effect on the success of female entrepreneurs.

"Our findings suggest women should not give up too readily, because their chance of success increases as they move to later life stages, and their perseverance ultimately tends to pay off," Zhao said.

For those in their 30s and 40s, the prospects aren't quite as good. Zhao concluded that midlife is a challenging time to start a business. Child care and elder care obligations also require valuable time and financial resources, and entrepreneurs do not have parental leave or day care benefits.

"Although it is generally commendable to pursue one's entrepreneurial aspiration," Zhao said, "we suggest that early mid-life individuals carefully evaluate all of the resources at hand and take a realistic view of this career path before taking the leap."

With many resources available to young entrepreneurs, Zhao suggests his research supports the idea that government agencies and business incubators should identify channels to foster entrepreneurship for older adults as well.

They say variety is the spice of life, and now new discoveries from Johns Hopkins researchers suggest that a certain elemental 'variety'--sulfur--is indeed a 'spice' that can perhaps point to signs of life.

These findings from the researchers' lab simulations reveal that sulfur can significantly impact observations of far-flung planets beyond the solar system; the results have implications for the use of sulfur as a sign for extraterrestrial life, as well as affect how researchers should interpret data about planetary atmospheres.

A report of the findings was published today in Nature Astronomy.

"We found that just a small presence of sulfur in the atmosphere, less than 2%, can have major impacts on what, and how many, haze particles are formed," says Chao He, an assistant research scientist in the Department of Earth and Planetary Sciences at The Johns Hopkins University and the study's first author.

"This entirely changes what scientists should look for and expect when they examine atmospheres on planets beyond our solar system."

While scientists already know that sulfur gases influence the photochemistry of many planets within the solar system such as Earth, Venus and Jupiter, not much is known about sulfur's role in the atmospheres of planets beyond the solar system, or exoplanets.

Due to its role as an essential element for life on Earth--emitted from plants and bacteria, and found in several amino acids and enzymes--scientists propose to use sulfur products to search for life beyond Earth. Understanding whether sulfur exists and how it affects these atmospheres can help scientists determine whether sulfur gases could be used as a source for life to originate, says He.

Researchers have performed few studies simulating planetary atmospheres with sulfur in the lab due to its high reactivity and difficulty to clean up once an experiment is done, says He. In fact, sulfur is so reactive that it would have even reacted with the experimental setup itself, so the research team had to upgrade their equipment to properly tolerate sulfur. To He's knowledge, only three other studies that simulated sulfur chemistry in the lab exist, and those were to understand its role in Earth's atmosphere; this is the first lab-run simulation to study sulfur in exoplanet atmospheres.

Chao and colleagues performed two sets of experiments using carbon dioxide, carbon monoxide, nitrogen, hydrogen, water and helium as a guide for their initial gas mixtures. One experiment included 1.6% sulfur in the mix and the other did not. The research team performed the simulation experiments in a specially designed Planetary HAZE (PHAZER) chamber in the lab of Sarah Hörst, assistant professor of Earth and Planetary Sciences and second author on the paper.

Once in the chamber, the team exposed the gas mixtures to one of two energy sources:
plasma from an alternating current glow discharge or light from an ultraviolet lamp. Plasma, an energy source stronger than UV light, can simulate electrical activities like lightning and/or energetic particles, and UV light is the main driver of chemical reactions in planetary atmospheres such as those on Earth, Saturn and Pluto.

After analyzing for solid particles and gas products formed, He and colleagues found that the mixture with sulfur had three times more haze particles, or solid particles suspended in gas.

Chao's team found that most of these particles were organic sulfur products rather than sulfuric acid or octasulfur, which researchers previously believed would make up the majority of sulfur particles on exoplanets.

"This new information means that if you're trying to observe an exoplanet's atmosphere and analyze its spectra, when you previously expected to see other products, you should now expect to see these organic sulfur products instead. Or, at least, you should know that it wouldn't be unusual for them to be there. This would change researchers' explanation and interpretation of spectra they see," says He.

Similarly, the findings should direct researchers to expect more haze particles if they are observing exoplanet atmospheres with sulfur, as just a small bit of sulfur increases haze production rate by three. Again, this would change how researchers interpret their findings and could be critical for future observation of exoplanets.

The last major implication of his findings, He says, is they push for heightened awareness that many sulfur products can be produced in the lab, in the absence of life, so scientists should be caution and rule out photochemically-produced sulfur before suggesting sulfur's presence as a sign for life.

The Arctic Ocean increasingly resembles the Atlantic, not only regarding its temperature but also the species that live there. However, scientists from the CNRS and Université Laval, Quebec[1] showed that an unprecedented strengthening of Atlantic currents is playing a major role in this phenomenon called 'Atlantification'. The research team studied Emiliania huxleyi, a marine microalgae that typically lives in temperate waters at lower latitudes. A specific feature of this organism is that it has a calcareous shell that reflects light so well that its massive development makes the ocean surface turquoise over large areas, a phenomenon that can be seen from space. As a result, the scientists were able to use satellite images to show that the strengthening of Atlantic currents largely explains the increased presence of temperate species such as Emiliania huxleyi in the Arctic Ocean. The findings are published in the journal Nature Communications (6 April 2020).

Before there were farms in southwest Michigan, there were prairies. For thousands of years, tall grass prairies stood undisturbed until European settlers turned the rich, highly productive soils to agriculture.

Today, tall grass prairies East of the Mississippi are virtually extinct.

But some landowners want to return land throughout the Midwest to its incredibly deep roots, converting abandoned, depleted and fallow agricultural fields to native prairie--with varying degrees of success.

Michigan State University's Lars Brudvig, associate professor in the Department of Plant Biology, and former MSU graduate student Anna Funk investigated fields of data going back 20 years to find out why some replanted prairies are healthier than others. Their research is published in Scientific Reports.

"Native prairie plants are rare on the landscape, so land managers need to intentionally spread seeds on the ground for them to come back," said Brudvig, whose lab partnered closely with farmers, land managers and various nature conservancies across Illinois, Indiana and Michigan for the study.

Each of the 83 sites Brudvig and Funk studied started from roughly the same point and had similar processes of ecological management. Controlled burning, targeted herbicides and regular mowing were common strategies, but every site had widely different outcomes.

The big question was, why?

"There was a bit of tantalizing evidence from just a couple of studies that suggested the weather you get during a prairie restoration can actually have a long-lasting effect on the success of the project," said Funk, who revisited northern Illinois prairies where she got her start as a plant ecologist with her mentor, Tom Simpson, at the McHenry County Conservation District. "It was an idea that land managers were familiar with anecdotally, but it hadn't been carefully studied."

The researchers looked at a wide swath of restored prairies--the best and the worst--to see if they could identify any patterns in fields planted in a particularly rainy or hot year. They interviewed the people who had planted each of the prairies in order to pinpoint planting dates, the number of prairie species planted and other details about ongoing management at each of the sites.

Then, they went out to each prairie, surveying the abundance and diversity of both weeds and native prairie plants and taking samples of the soil to test how productive each site was.

"When I did a big analysis of all of our data, I hoped to find some effect of the planting year, but I still assumed other factors would be most important, like how often the site had been managed with prescribed fire," Funk said. "I was very surprised to find not only an effect of weather, but that sometimes planting-year weather conditions had the biggest effect of all."

"We expected that in years where it rained more when the prairie was initially planted, it should turn out better because plants need water," Brudvig added. "But it's exactly the opposite because there are not only prairie plants at these sites, but weedy plant species that really respond to precipitation."

Even more surprising was how long the first year's weather left its mark on restored prairie systems.

"We thought rainfall would matter at first, but that we should see that signature in the data become less and less important as the sites got older and older," Brudvig said. "Instead, we saw the first-year weather conditions had a signature that persisted for decades."

The findings may seem disheartening as climate change brings wetter springs more often to the Midwest but recognizing weather signatures may be an important tool for restoration practitioners who are fighting to re-establish these extremely imperiled ecosystems.

"We suggest they use long-term weather forecasts to help predict if it will be a rainy or dry year so that it might be possible for land managers to focus more effort on starting prairies in what is expected to be a drier year," Brudvig explained. "They may also be able to invest more in weed control during rainy planting years by mowing the weeds above the prairie plants."

"I really hope this knowledge will be helpful to anyone planting prairies, as well as to ecologists more broadly who are doing experiments that could be affected by the weather," Funk said. "The next step will be to figure out how to best mitigate the weed-bomb that extra rain causes. I'm sure prairie managers already have lots of ideas on what to explore next."

Consuming a diet high in fiber was linked with a reduced incidence of breast cancer in an analysis of all relevant prospective studies. The findings are published early online in CANCER, a peer-reviewed journal of the American Cancer Society (ACS).

Because studies have generated inconsistent results regarding the potential relationship between fiber intake and breast cancer, Maryam Farvid, PhD, of the Harvard T.H. Chan School of Public Health, and her colleagues searched for all relevant prospective studies published through July 2019.

When the investigators pooled data from the 20 observational studies they identified, individuals with the highest consumption of fiber had an eight percent lower risk of breast cancer. Soluble fiber was associated with lower risks of breast cancer, and higher total fiber intake was associated with a lower risk in both premenopausal and postmenopausal women.

"Our study contributes to the evidence that lifestyle factors, such as modifiable dietary practices, may affect breast cancer risk," said Dr. Farvid. "Our findings provide research evidence supporting the American Cancer Society dietary guidelines, emphasizing the importance of a diet rich in fiber, including fruits, vegetables, and whole grains."

Importantly, the findings do not demonstrate that dietary fiber directly reduces breast cancer risk, and a randomized clinical trial is needed to test such cause and effect.