Earth

The growing global population and continued economic development will likely require a significant increase in water demand, especially in developing regions. At the same time, climate change is already having global, regional, and local impacts on water availability. Ensuring that the changing supply can meet the continuously growing demand without compromising the sensitive aquatic environments from which it is derived, is clearly a huge challenge that will require strategies and policies informed by science.

In order to aid in the accurate assessment of water supply and the demands of both people and the environment, IIASA researchers have developed a large-scale hydrological and water resources model ? the Community Water Model (CWatM). The model can simulate the movement, distribution, and management of water both globally and regionally to evaluate water availability in terms of water demand and environmental needs. It includes an accounting of how future water demand will evolve in response to socioeconomic change and how water availability will be influenced by climate change. The integrated modeling framework considers water demand from agriculture, domestic needs, energy, industry, and the environment.

The Community Water Model has a modular structure that is open source and uses state-of-the-art data storage protocols as input and output data, while being community-driven to promote the team's work among the wider water community. It is flexible enough to change between scales, to be integrated with water quality and the hydro-economy, and to be linked with other IIASA models like MESSAGE, the Global Biosphere Management Model (GLOBIOM), BeWhere, and the Environmental Policy Integrated (EPIC) model.

Because the modeling framework is general, it can also be adapted to address new interdisciplinary research questions, which means that it opens the door to many potential applications to explore connections between the nexus aspects of energy, land, and water. According to the researchers, the main novelty of the model is that it combines existing good practice in various scientific communities beyond hydrology itself, rather than provide entirely new concepts for modeling hydrological and socioeconomic processes. Furthermore, the model is customizable to the needs of different users with varying levels of programming skills. This will support and enable different stakeholder groups and scientific communities beyond hydrology and of varying capacities to engage with a hydrological model in support of their investigations

"The Community Water Model represents one of the new key elements of the IIASA Water Program to assess water supply, water demand, and environmental needs at the global and regional level. It is the first step towards developing an integrated modeling framework, that can be used to explore the economic trade-offs between different water management options, encompassing both water supply infrastructure and demand management. With this framework we are able to provide vital information to decision and policymakers," says Peter Burek, an IIASA researcher and the lead author of a new paper outlining the model's development published in Geoscientific Model Development.

The Community Water Model will continue to be developed to include more features such as a routing scheme related to reservoirs and canals to better simulate water availability in both agricultural and urban contexts, and the capacity to explore aspects related to groundwater management.

(Boston)--Experiences of racism are associated with lower subjective cognitive function (SCF) among African-American women.

Rates of incident dementia and Alzheimer's Disease (AD) are higher in African Americans than in white Americans. In many studies, older African Americans perform more poorly on neuropsychological cognition tests compared to white Americans. Experiences of racism are common among African Americans, with 50 percent or more respondents to a 2017 national survey reporting such experiences. These institutional and daily forms of racism have been associated with increased risks of various conditions that can impair cognition, including depression, poor sleep, type 2 diabetes and hypertension.

Using data from the Black Women's Health Study (a prospective cohort study established in 1995, when 59,000 black women aged 21 through 69 years enrolled by completing health questionnaires) researchers from Boston University's Slone Epidemiology Center quantified the association between experiences of racism and SCF, based on six questions about memory and cognition.

They found that experiences of both daily and institutional racism were associated with decreased SCF. Women reporting the highest level of daily racism had 2.75 times the risk of poor SCF as women reporting the lowest level of daily racism. Women in the highest category of institutional racism had 2.66 times the risk of poor SCF as those who reported no such experiences.

"Our findings of a positive association of experiences of racism with poorer subjective cognitive function are consistent with previous work demonstrating that higher perceived psychological stress is associated with greater subjective memory decline," explains senior author Lynn Rosenberg, ScD, epidemiologist at the Slone Epidemiology Center at Boston University and a principal investigator of the Black Women's Health Study. "Our work suggests that the chronic stress associated with racial discrimination may contribute to racial disparities in cognition and AD," added Rosenberg, who is also a professor of epidemiology at Boston University School of Public Health.

Future work is needed to examine whether exposure to institutional and daily racism accelerates conversion to Alzheimer's dementia and/or increases levels of AD biomarkers, such as cerebrospinal fluid or PET markers of amyloid ? and tau pathology, according to the researchers.

Today, we pull the veil back on the secret sex lives of leeches and how researchers at McMaster University and Fisheries and Oceans Canada are using that information to learn about endocrine disrupting chemicals. Leeches, who gained worldwide popularity when making their film debut in the blockbuster "Stand by Me" in 1986, have actually been around much, much longer. They are found on every continent in freshwater habitats where there is little flow. They are popular bait for fishing, and doctors continue to use them in medical treatments.

We know a lot about leech reproduction. For example, leeches are hermaphroditic, which means they have both male and female sex organs, but that is not all that uncommon for invertebrates. Some families of leeches demonstrate protrandry (they start life as a male and then change into a female), while others self-fertilize, brood eggs and show parental care. Still others cross-fertilize with other leeches, sometimes implanting sperm in one or both of the partners' body walls and sometimes directly introducing sperm into a genital pore with a penis. Their reproductive cycle also varies across families, with some only reproducing one time in their life, and others reproducing multiple times in their lifespan.

We also know a little about the impact of environmental contaminants on leeches. As a matter of fact, leeches have been shown to be highly sensitive to metals in aquatic systems. Leeches can be useful as an environmental quality indicator, as the aquatic ecosystems where leeches are found are often a sink for contaminants. However, even though studies have looked at how some environmental contaminants affect leech populations, very little is known about how they influence leech community composition, species abundance, egg production, growth rates and gonad size. For example, plenty of studies have been conducted at the Experimental Lakes Area in Ontario, Canada, to study the effects of synthetic estrogen (17α-estradiol [EE2]) on fish, other types of invertebrates, and amphibians. Synthetic estrogens are used in oral contraceptives and enter aquatic system when they are not completely broken down in wastewater treatment plants. The compound EE2 was shown to have profound effects on fathead minnows, collapsing their population, and occasionally affected amphibian hatching success and gonad development. However, little attention was given to the effect of EE2 on leech communities until now.

In their article, published in Environmental Toxicology and Chemistry, Karen Kidd, professor at McMaster University and lead author, documents that the EE2 appeared to have little impact on the abundance of leeches, but notes that there was "increased condition in one species and some changes in relative gonad sizes of reproductive organs." This may be because there was an increase in their food supply of other invertebrates, an indirect effect of EE2 linked to reduced fish numbers. For the leech species H. marmorata, the weight of the epididymis (a duct behind the testes) and the sperm sac size decreased, but the length of the testes, prostrate and penis sheath increased in exposed individuals. Likewise, EE2-exposed leeches were associated with growth in ovisac and albumen and vaginal bulb lengths. However, these leeches showed few individual-level and no population- or community-level responses, suggesting that they are much less sensitive to this endocrine disruptor than fish. There had been some thought that leeches may be an ideal study species for assessing contaminant effects - as noted above, they are sensitive to metals and ubiquitous - but, this study suggests that they may be less responsive to endocrine disrupting compounds, such as EE2.

A comparison of children in Hong Kong, mainland China and the UK has found that British boys' development of key thinking skills, known as 'executive functions', is unusually reliant on their socio-economic status.

The findings emerged from an ongoing project which is exploring contrasts in the development of these skills in Eastern and Western societies and their relationship to academic achievement. Executive functions are cognitive skills that help us to meet goals - such as our ability to ignore distractions or switch between tasks - and they significantly affect children's performance at school.

Across two linked studies, researchers found that the socio-economic background of British boys is directly connected to these skills. Those from wealthier families typically performed better in tests of their executive functions, while those from less-affluent backgrounds did worse.

The connection was far less direct for British girls, however - and absent altogether among boys or girls from mainland China and Hong Kong, who, despite being generally less affluent than their British peers, consistently outperformed them in the tests.

These results imply that specific cultural factors in children's lives that shape the acquisition of executive functions, also influence socio-economic gaps in academic outcomes. It is not clear what these cultural 'drivers' are, but they may include differences in curriculum, parenting, or attitudes to education.

The research was by a team of academics from the Faculty of Education and the Centre for Family Research, University of Cambridge.

Dr Michelle Ellefson, Reader in Cognitive Science at the Faculty of Education, said: "Based on other research, we might have anticipated a direct link between socio-economic status and executive functions; in fact, this existed only for British boys. Pretty much any test pupils do at school requires executive functions, so if we want to reduce the achievement gap between children from different backgrounds, it's important that we understand the mechanisms behind that relationship."

Claire Hughes, Professor of Developmental Psychology in the Centre for Family Research, said: "There is concern in the UK that among children from less-advantaged backgrounds, boys in particular often under-perform academically, and the possibility has been raised in some research that features of their home environment play a role in this. What is interesting here is that we saw no relationship between socio-economic status and executive functions for boys in Hong Kong and China. We need to investigate why that might be the case."

The research was part of the Family Thinking Skills project, which is exploring links between executive functions, school attainment and cultural differences in Britain and Hong Kong by comparing data from children and parents in both countries. Executive functions are mediated by the brain's prefrontal cortex, which develops into our mid-20s, and this means that they are likely to be shaped in part by cultural influences like upbringing and environment.

The latest pair of studies looked at whether socio-economic status, which is known to influence children's performance at school, does so because it impacts on their executive functions, or has an effect independent of cognitive skills. They also investigated how consistent the relationship is across genders. "Very little research has looked at this in Asia, and big differences with the UK might point to cultural differences driving attainment," Ellefson said.

Initially, the researchers used data from 835 children aged 9 to 16 living in Hong Kong and the UK. The participants completed computer-based thinking games to test their executive functions, and various mathematical tests to assess numeracy. Data about socio-economic status was also provided by their parents and through a survey.

Because children in Hong Kong are highly adept with computers from an extremely young age, which might distort the results in the thinking skills tests, a second study was undertaken with 453 children in Shandong, China, led by PhD researcher Chengyi Xu. This deliberately targeted children whose use computers much less.

Overall, British students performed significantly worse in the numeracy tests, and their executive functions were about two years behind the level of their Chinese peers, even though British children tended to be from wealthier backgrounds. Within countries, there was little difference between girls' and boys' average test scores, although girls displayed slightly higher cognitive flexibility.

The children's levels of executive function and socio-economic status were both shown to affect their numeracy scores, but in most cases they did so independently of each other. The exception was British boys, for whom socio-economic status directly predicts executive functions, which in turn affects their numeracy.

The researchers also measured general cognitive skills, beyond executive functions alone. Here, they found that both boys and girls from wealthier backgrounds in the UK tend to have better general cognitive skills than those from less-affluent families, whereas in China and Hong Kong, there was no relationship to socio-economic status.

The data from Shandong also confirmed that computer usage had no effect on the acquisition of executive functions.

The results strongly suggest that cultural distinctions have shaped a gulf between the thinking skills of British and Asian children, with consequences for their relative attainment. More research is needed to establish what these are, but the nature of the school curriculum, teaching styles, parental expectations, or social attitudes to education, may be some of the factors involved.

In addition, the close link between socio-economic background and thinking skills for British boys in particular suggests that understanding more about these cultural drivers may help to narrow the attainment gap within the UK. "A clearer picture of why differences exist in the development of executive functions between children in Britain and Hong Kong would potentially help to inform interventions to reduce that gap," Hughes said.

The seventh tropical depression of the Eastern Pacific Ocean has formed. NASA's Terra satellite used infrared light to identify the area of strongest storms and coldest cloud top temperatures in Tropical Depression 7E.

Tropical Depression 7E formed in the Eastern Pacific Ocean well to the southwest of Mexico's Baja California Peninsula. However, the storm is expected to be short-lived because it is expected to track over waters too cool to maintain it. Tropical cyclones need sea surface temperatures of at least 26.6 degrees Celsius (80 degrees Fahrenheit) to maintain strength.

On July 20 at 2:30 a.m. EDT (0630 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA's Terra satellite analyzed Tropical Depression 7E's cloud tops in infrared light. Infrared data provides temperature information, and the strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures. Terra found one small area where temperatures were as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 Celsius) in the southeastern quadrant. Cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

At 5 a.m. EDT (0900 UTC), the center of Tropical Depression 7E was located near latitude 18.0 degrees north and longitude 129.3 degrees west. That is about 1,300 miles (2,090 km) west-southwest of the southern tip of Baja California. The National Hurricane Center (NHC) reported that the depression is moving toward the northwest near 12 mph (19 kph), and this motion is expected to continue through Monday night, followed  by a turn the west by early Tuesday. Maximum sustained winds are near 35 mph (55 kph) with higher gusts. The estimated minimum central pressure is 1007 millibars.

NHC Forecaster Stacy Stewart noted, "Although the vertical wind shear is expected to remain low at less than 5 knots for the next 24 hours or so, the small cyclone is already moving over sub-26 degree Celsius sea-surface temperatures (SST), with slightly cooler water ahead of the system. The ingestion of cooler and drier air, along with the cool SSTs, is expected to weaken the system below depression status by 24 hours."

Little if any change in strength is forecast during the next 48 hours. The depression is expected to be a short-lived tropical cyclone that will degenerate into a remnant low by Tuesday morning.

Over 360 scientists from 42 countries - led by the University of Göttingen and Westlake University China - call for transition of food production systems to agroecological principles.

Humans depend on farming for their very survival but this activity takes up more than one third of the world's landmass and endangers 62% of all threatened species globally. However, agricultural landscapes can support, rather than damage, biodiversity, but only through a global transition to agroecological production. An international team of over 360 scientists from 42 countries, led by the University of Göttingen and Westlake University in China, argue that agroecological principles should be integrated in the post-2020 Global Biodiversity Framework, which aims to reduce threats to biodiversity and will be decided at the 15th Convention of the Parties (COP15) meeting in China. Their Correspondence article was published in Nature Ecology & Evolution.

Reversing the trend in species decline is essential for the benefit of both people and the planet, but it will require coordinated actions and sustainable agriculture. Intensive farming relying on excessive pesticides and fertiliser has negative effects on biodiversity. The authors argue that farming landscapes can provide habitats for biodiversity, promote connectivity between protected areas and increase species' ability to respond to environmental threats. The authors' research agenda includes enhancing global research networks, expanding technical innovation and improving communication. The authors emphasise the importance of working with and supporting farmers, indigenous people and local communities. Diversification in crops together with new varieties and combinations, for instance, can sustain yields. In addition, these actions can support biodiversity and ecosystems whilst providing more nutritious and healthy food for all.

This year is crucial for biodiversity, not just because time is running out to conserve insects and other wildlife, but also because the 15th Convention of the Parties (COP15) will meet in China for the UN Biodiversity Conference, now in 2021 due to COVID-19. At COP15, the post-2020 Global Biodiversity Framework will be agreed which has targets to reduce threats to biodiversity. The authors have elaborated how agroecological principles can help meet each of these targets.

Dr Thomas Cherico Wanger from Westlake University China and University of Göttingen and first author of the correspondence reports, "The importance of agroecology to change agriculture and protect biodiversity has been recognized by many top level organizations, in the scientific community, and by practitioners, which is also reflected in the number and affiliations of signatories of our Correspondence. Following our positive discussions with representatives of the COP15, I hope that this correspondence can help to stimulate discussions in the policy arena and make a real impact on agricultural production systems."

Professor Teja Tscharntke, co-author and Head of the Agroecology Research Group at the University of Göttingen, adds: "Agroecology has the potential to change the way we 'do agriculture'. We hope that our comprehensive research agenda will help to chart the path to sustainable, diversified agriculture and biodiversity conservation in the future."

Below please find a summary and link(s) of new coronavirus-related content published today in Annals of Internal Medicine. The summary below is not intended to substitute for the full article as a source of information. A collection of coronavirus-related content is free to the public at http://go.annals.org/coronavirus.

Data from Iran shows a nearly 25 percent 30-day cumulative mortality rate for hospitalized COVID-19 patients
Older patients and those with coexisting diseases were more likely to die in the hospital

Researchers from Tehran University of Medical Sciences reviewed data from a national registry to assess the characteristics and mortality of hospitalized patients with COVID-19. The Medical Care Monitoring Center of the Ministry of Health and Medical Education (MOHME) of Iran mandated all hospitals to register patients admitted with a diagnosis of confirmed or suspected COVID-19. The data showed that among 62,955 patients admitted to the designated hospitals between February 20 and April 20, 2020, 29,111 tested positive for COVID-19. When all patients admitted during the study period were used in a Kaplan-Meier analysis of survival, the cumulative risk for in-hospital mortality in 30 days was 24.4 percent. Patients who were over the age of 65 were significantly more likely to die from COVID-19, as were those with any coexisting condition, such as heart disease or diabetes. The most prevalent symptom among patients who perished was shortness of breath. Read the full text: https://www.acpjournals.org/doi/10.7326/M20-2911.

Media contacts: A PDF for this article is not yet available. Please click the link to read full text. The lead author, Mohammad Jalili, MD, can be reached directly at mjalili@tums.ac.ir.

With their tough skins, pointy armor and legendary stamina, cacti are made to defend themselves from whatever nature throws at them.

But large solar energy facilities are one threat that cacti weren't built to withstand, according to a study by the University of California, Davis.

The study, published July 20 in the journal Nature Sustainability, chronicles the impacts of ground-mounted solar energy development in the Mojave Desert on native plants and their cultural significance to indigenous tribes in the region.

"We're talking about iconic and threatened plants -- cacti, especially, and Mojave yucca," said co-leading author Steve Grodsky, an assistant research ecologist at UC Davis. "These are the plants most people envision when they think about the desert, and they're also the most negatively affected by solar energy development."

LOCATION, LOCATION, LOCATION

Solar energy is a key strategy for reducing greenhouse gas emissions and the threats of climate change. But like any development, where it's sited affects its overall environmental sustainability.

UC Davis Assistant Professor Rebecca R. Hernandez and Grodsky are exploring where renewable energy can best coexist with wildlife, biodiversity and the environment to achieve overall sustainability. Their work is part of their Wild Energy Initiative, a research initiative of the UC Davis John Muir Institute of the Environment, and of the Energy and Efficiency Institute.

"This is really our moment to double down," said co-leading author Hernandez. "We need to not only build out renewable energy, we also need to develop it in the places that produce positive impacts. This isn't just about saving the cacti. It's about our need to achieve both climate change goals and sustainable development goals, which include protecting terrestrial ecosystems, at the same time."

NATIVE PLANTS AND NATIVE PEOPLES

For the study, the scientists measured the impact of solar development decisions on desert plants at Ivanpah Solar Electric Generating System, one of the world's largest concentrating solar power plants. They found negative impacts on the desert scrub plant community, including plants of cultural significance to 18 indigenous tribes.

Among them are the Mojave yucca, a Joshua tree relative. Its leaves and fiber historically were used for making shoes, baskets, and building structures. Its roots can be used for soap, hence its common name "soap yucca." Other plants have provided medicine, tools and food, such as the fruits and pads of the beavertail prickly pear cactus.

MANAGEMENT OPTIONS AND IMPACTS

There are a variety of ways to prepare land for solar installations, and some of these methods are more harmful to the desert plant community than others:

Bulldozing, or "blading," scrapes layers of earth away from the site. It's the most damaging to cacti, Mojave yucca and other native plants. It also primes the site for invasive grasses like Schismus, which present a fire risk to deserts maladapted to wildfire.

Mowing also destroys cacti and Mojave yucca, but creosote and perennial shrubs can recover from it.

"Halos" are roped off areas known to hold sensitive species that create islands of undeveloped areas within the facility. They can be effective for conserving native plants, including cacti and Mojave yucca.

"From a management perspective, there are things we can do to help conserve native desert plants at solar facilities," Grodsky said. "But it's best to develop solar energy in marginalized lands like urban areas, places where ecosystems are heavily altered, rather than undeveloped desert."

Previous research by Hernandez, Grodsky and colleagues examined dozens of alternatives to installing solar on undisturbed lands. These include siting solar on contaminated sites (like Superfund sites), landfills and salt-affected lands. Other options include "agrivoltaics," which co-locate agriculture and solar energy, and -- perhaps most promising -- on the rooftops of large commercial buildings, such as warehouses.

Researchers from KU Leuven, the International Institute of Applied Systems Analysis (IIASA) and RTI International investigated the effects of trade on hunger in the world as a result of climate change. The conclusion is clear: international trade can compensate for regional food shortages and reduce hunger, particularly when protectionist measures and other barriers to trade are eliminated.

Climate change has consequences for agriculture worldwide, with clear differences between regions. Expectations are that sufficient food will remain available in the Northern hemisphere, but in regions such as Sub-Saharan Africa or South Asia, falling crop yields may lead to higher food prices and a sharp rise in hunger. Further liberalisation of world trade can relieve these regional differences: "If regions like Europe and Latin America, for example, where wheat and corn thrive, increase their production and export food to regions under heavy pressure from global warming, food shortages can be reduced," says doctoral researcher Charlotte Janssens. "It sounds quite obvious, but there are many barriers that complicate this free trade."

Tariffs and infrastructure

Import tariffs are a major barrier to international trade in food. They increase the cost of importing basic food crops like wheat, corn or rice. Around a fifth of the worldwide production of these grains is traded internationally. That makes good trade agreements very important in the battle against hunger. Professor Miet Maertens explains: "In the early 21st century, we saw a major liberalisation of the international market. This caused the average import tariffs on agricultural products in Europe, Sub-Saharan Africa and South Asia to drop by a third. Our research shows that this liberalisation makes global food provision less vulnerable to climate change. We also see that further reduction and phasing-out of tariffs can intensify this positive effect."

Besides, there are also other barriers. In some countries, the logistical aspect is a sticking point. Roads are sometimes poor or ports are not equipped for loading and unloading large container ships. Countless complicated trade procedures can drive up the effective cost of trade. "A global food strategy must go hand in hand with improvements to trade infrastructure," argues Charlotte Janssens.

60 scenarios

The international research team, consisting of scientists from KU Leuven, IIASA and RTI International, among others, are making their recommendations based on 60 scenarios. They took into account different forms of trade policy, along with climate change varying from a 2 to 4-degree warming of the Earth. 2050 was set as the horizon for each scenario. "Under the current barriers to trade, the worst-case climate scenario of a 4-degree warming will lead to an extra 55 million people enduring hunger compared to the situation without climate change. If vulnerable regions cannot increase their food imports, this effect will even rise to 73 million," argues Janssens. Where barriers to trade are eliminated, 'only' 20 million people will endure food shortages due to climate change. In the more mild climate scenarios, an intensive liberalisation of trade may even prevent more people from enduring hunger owing to climate change.

Yet a liberalisation of international trade may also involve potential dangers. "If South Asian countries would increase rice exports without making more imports of other products possible, they could be faced with increased food shortage within their own borders," warns Charlotte Janssens. "A well thought-out liberalisation is needed in order to be able to relieve food shortages properly."

Crisis and protectionism

"Sadly enough, we see that in times of crisis, countries are inclined to adopt a protectionist stance. Since the start of the current corona crisis, around ten countries are closing their borders for the export of important food crops", says Janssens. "In the context of climate change, it is highly important that they avoid such protectionist behaviour and instead continue to maintain and utilise the international trade framework."

The Yangtze Bank is a flat and broad shallow water, located at the junction of the Yellow Sea and the East China Sea. Large river discharge and strong wind- and tide-induced mixing created a large amount of land sediment discharge as well as the resuspension of bottom sediment, making the Yangtze Bank one of the most turbid coastal areas in the world (Figure 1). The high resolution distribution and tidal variation of suspended sediment over the Yangtze Bank have been revealed in a recent study.

The relevant article "Tidal variation of total suspended solids over the Yangtze Bank based on the geostationary ocean color imager" was published in Science China: Earth Sciences recently, written by a group led by Daji HUANG from the second Institute of Oceanography, Ministry of Natural Resources. The world's first Geostationary Ocean Color Imager (GOCI) was used to reveal the high resolution spatial pattern and tidal variation of total suspended solids (TSS) over the Yangtze Bank in the Yellow and East China Seas during the winter.

The movement and distribution of suspended sediment are accompanied by processes such as pollutant transmission, nutrient transport, and changes in optical characteristics of seawater, which directly affect the hydrodynamic and ecological environment of seawater. Therefore, sediment transport and distribution in the sea have received attention from oceanographers. So far, scholars have conducted extensive research on suspended sediment transport in different sea areas of the world. Among them, the research on the spatio-temporal variation of suspended sediment in the Yellow and East China Sea, and especially the Yangtze Bank has obtained a wide range of research results. Previous studies on the spatio-temporal characteristics of suspended sediment over the Yangtze Bank had demonstrated that the suspended sediment exhibits obvious inter-annual, seasonal and short-term variation (spring-neap tidal cycle and synoptic scale). These characteristics are modulated by multi-scale hydrodynamic forcing (runoff, wave, tide) and atmospheric forcing (wind, air temperature).

Based on previous studies, this research used the world's first Geostationary Ocean Color Imager, GOCI, to study the high resolution spatial distribution and tidal variation of suspended. Compared with traditional polar orbit satellites, GOCI has the characteristics of high spatial and temporal resolution, and is suitable for monitoring the short-term dynamic processes in coastal ocean. The paper quantified the fronts of TSS in the Yangtze Bank and found that the suspended sediment distribution showed a tongue-shaped structure, which decreases further offshore in a stepwise manner, and described the tidal variation of TSS concentration in detail. In terms of tide-induced mixing, this dynamic analysis shows that both the topography and the tidal currents play an important role in the spatio-temporal variation of TSS during the tidal period. In particular, spatial distribution is primarily determined by the topography, whereas the temporal variations in tidal scale are determined by the tidal currents.

This research enriched the study of the multi-scale changes of suspended sediment over the Yangtze Bank. The research results enhance our understanding of the short-term changes to TSS in the Yellow and East China Seas, and it provides an observational basis for the numerical study of sediment transportation and resuspension over the Yangtze Bank, and it has a scientific significance and reference value for multi-disciplinary researches such as marine ecological environment, marine remote sensing, marine dynamics, etc.

Foraminifera, an ancient and ecologically highly successful group of marine organisms, are found on and below the seafloor. Geobiologists at Ludwig-Maximilians-Universitaet (LMU) in Munich report that several species not only survive, but thrive, in these oxygen-free sediments. 

Foraminifera are unicellular marine organisms that are found on and within seafloor sediments. Most species construct porous mineralized shells and capture prey by extending cytoplasmic filaments though these pores. The group is highly species rich, and their preserved fossilized remains show that they were already present in the oceans at the beginning of the Cambrian Era, 560 million years ago. Their shells have considerable fossilization potential, which explains why they serve as index fossils for the dating of a number of geological eras. Moreover, foraminifera are of great ecological significance - owing to their contributions to carbon and nitrate cycles, for instance - and their shells play an important role in the reconstruction of ancient climates. However, despite their well-established status as proxies for environmental conditions, relatively little is known about the biology of contemporary species of foraminifera. LMU geobiologists led by Professor William Orsi of the Department of Earth and Environmental Sciences and the GeoBio Center at LMU, in cooperation with Raphaël Morard and Michal Kucera (Bremen University), have now investigated their metabolism at the molecular level, and found that some species of foraminifera can survive - and indeed thrive - in oxygen-free (anoxic) habitats that would be deadly for other eukaryotes. The results of the new study appear in The ISME Journal. 

Foraminifera have been previously found in oxygen-poor and even anoxic marine sediments. To learn more about the adaptations that enable them to survive in this inhospitable environment, Orsi and his team examined species sampled from a sediment core recovered from the seafloor off the coast of Namibia. Much of the sediment in this core was anoxic and rich in the toxic gas hydrogen sulfide. Nevertheless, the team found large numbers of Foraminifera at these levels, where they had more than 10 times higher activity compared to the shallower sections with higher levels of oxygen. "Up to now, marine biologists have assumed that, under such conditions, Foraminifera manage to survive on the seafloor and die when they are buried beneath it," says Orsi. "Our results, on the other hand, surprisingly demonstrate that some species of Foraminifera are metabolically more active in anoxic sediments." In other words, it looks as if these organisms are just not eking out a living in these habitats, they appear to be very well adapted to the challenging conditions. Moreover, incubation experiments confirmed their preference for anoxic environments, whereby the activity of the Foraminifera increased up to 40 times in anoxic conditions. 

Orsi and his colleagues went on to study the metabolic pathways employed by these foraminiferan species by analyzing the messenger RNAs (mRNAs) found in sediment samples. mRNAs are copied from genomic DNA, and encode the instructions for the synthesis of the proteins required for cell function. They therefore allow one to identify the set of genes that are active in the local cell population, and the spectrum of biochemical activities required for cellular metabolism in a given environment. In this case, the analyses revealed that foraminifera make use of a variety of metabolic pathways - for the fermentation of sugars and amino acids, for instance. In addition, they show that, in addition to capturing and digesting prey, foraminifera in the anoxic zones can exploit soluble organic material as a source of carbon and energy. "Presumably, foraminifera play an important and hitherto overlooked role in anaerobic nutrient cycles," says Orsi. This ability to thrive in such otherwise inhospitable anoxic environments with high levels of toxic hydrogen sulfide gas could be part of the explanation for their ecological success. After all, the group has managed to avoid a number of mass extermination events over the past 500 million years - many of which were associated with a marked reduction in the availability of oxygen and accumulation of toxic hydrogen sulfide that was responsible for killing off numerous now extinct animal species.

Some of the fastest video cameras ever developed have been used by KAUST researchers to clarify how molecular-scale changes to water surfaces may impact the performance of industrial-scale purifications.

One factor that influences the stability of emulsions is how quickly small bubbles or droplets join together into larger droplets. Ivan Vakarelski, a research scientist in Sigurdur Thoroddsen's lab, notes that this type of coalescence is driven by variables ranging from bubble size, collision speed, and the "freedom" of molecules located at liquid surfaces.

"When liquids contact a solid, they tend to stick due to strong molecular forces. In contrast, a clean liquid exposed to air can move along relatively easily--we call that a mobile interface," explains Vakarelski. "It's a fundamental property that determines the behavior of many foams and emulsions."

Recently, Thoroddsen and his team used their expertise at high-speed imaging to observe collisions between air bubbles formed in a perfluorocarbon, a liquid with similar viscosity to water that can be refined to an ultrapure state. To their surprise, these bubbles did not coalesce as fast as anticipated. Instead, the high mobility of the air- perfluorocarbon interface caused the bubbles to repeatedly bounce off each other before merging.

In their latest work, the KAUST researchers broadened their investigations to the world's most important liquid--water. A clean air-water interface is supposed to be mobile, however, numerous studies suggest they have low molecular freedom because they are highly susceptible to contamination.

To resolve this quandary, Vakarelski helped design an experiment that used thin films of fatty acids to completely immobilize a free water surface. Then, they released millimeter-sized air bubbles that floated to the interface and crashed into it. When images of the rebounding bubbles were compared to ones taken on purified water surfaces, the team saw that the fatty acid film drastically reduced the degree of bouncing.

"A common belief is that once water is exposed to the atmosphere in a laboratory, it's impossible to keep it clean enough to be mobile," says Vakarelski. "However, our study shows that this is not correct--a standard purification device produces an interface that bounces bubbles back quite strongly."

Successful tests of this approach with other liquids, such as ethanol, indicate that bubble analysis could help solve problems in food processing applications as well as chemical production.

EAST LANSING, Mich. - You might think social media is addictive, but how do certain platforms measure against one another? Researchers from Michigan State University and California State University-Fullerton conducted the first study comparing problematic use between Facebook and Snapchat -- while also uncovering surprising findings about users' personality traits.

"Both Facebook and Snapchat have separate features that make users want to keep coming back and using these platforms," said Dar Meshi, a cognitive neuroscientist and assistant professor in MSU's College of Communication Arts and Sciences. "We were interested in measuring not only problematic use, but also the specific social rewards people might be looking for when using them."

The study, published in the journal Addictive Behaviors Reports, measured 472 college-aged participants' time spent on the two platforms, quit attempts and problematic use. The researchers also asked participants to fill out a questionnaire that measured their preferences for social rewards -- or, types of social interactions they enjoy -- such as admiration, passivity, prosocial interactions, sexual relationships, sociability and, lastly, negative social potency.

"We found that participants spent more time on Snapchat than on Facebook, and they also demonstrated more problematic use of Snapchat," Meshi said. "Surprisingly though, participants reported more attempts to quit Facebook."

While Meshi and co-author Ofir Turel, a professor of information systems and decision sciences, did not examine what specific mechanisms within the two platforms led to problematic use, they did find a psychological parallel with users' problematic use.

"Remarkably, we saw a correlation between problematic use on both platforms and negative social potency -- which is people's desire to be cruel, callous and use others for personal gain," Meshi said. "These survey items asked about one's enjoyment embarrassing or angering others, for example."

Meshi explained that people with more problematic use had higher preference levels for negative social potency rewards; so, the more problematic your use is, the more you enjoy these negative social interactions. Negative social potency, admiration (receiving admiration from others) and sociability were found to be positively associated with problematic Snapchat use, but only negative social potency correlated with problematic Facebook use.

The other surprising finding, Meshi said, was that participants attempted to quit Facebook more than Snapchat.

"Given our finding that college students' use of Snapchat is more problematic, we thought there would have been more attempts to quit or curtail use," Meshi said.

Meshi explained that understanding which social reward preferences are related to problematic use is essential for clinical psychologists as they treat patients.

"If there's a patient who says they're having problems overusing these platforms, the clinician will have a better understanding as to what drives them socially and should be better able to help them," said Meshi.

An international group of researchers have discovered that inhibiting AHR (aryl hydrocarbon receptor), a protein with roles in regulating immunity, stem cell maintenance and cellular differentiation, enables the immune system to combat replication of zika virus in the organism far more effectively. In experiments performed at the University of São Paulo’s Biomedical Sciences Institute (ICB-USP) in Brazil, the antiviral therapy proved capable of preventing the development of microcephaly and other malformations in mouse fetuses whose mothers were infected while pregnant.

The study was supported by FAPESP. An article describing the results was published on July 20 in the journal Nature Neuroscience.

“In the experiments, we used an experimental drug that inhibits AHR and observed a decrease in replication of both zika virus and dengue virus. We now plan to test the effectiveness of the therapy against the novel coronavirus,” said Jean Pierre Peron, a professor at ICB-USP and co-principal investigator for the project alongside Cybele Garcia, a virologist at the University of Buenos Aires in Argentina, and Francisco Quintana, a professor of neurology at Harvard Medical School in the United States.

The experimental model used in the study was the same as that used by Peron’s group in 2016 to prove a causal link between zika virus and microcephaly (read more at agencia.fapesp.br/23286/). On that occasion female mice of the SJL strain, which are much more susceptible to zika infection than other laboratory animals, were infected with the virus between the tenth and twelfth day of pregnancy. When the pups were born, the researchers found a significant reduction in cortical layer thickness, as well as alterations in the number and morphology of cortical and other brain cells. They also found that the virus replicated far more rapidly in placenta and in the pups’ brains than in other organs.

“We repeated this experiment with a difference,” Peron said. “Shortly before we infected the pregnant females with zika, we began orally administering the AHR inhibitor. The treatment continued until the end of the gestational period. The pups had normal brains in terms of size and weight, and a far lower viral load than the non-treated control group. Viral load was almost undetectable in both the placenta and the central nervous system. In addition, histopathological analysis showed that there was no reduction in cortical layer thickness and that the number of nervous system cells killed by the virus was much smaller.”

According to Peron, no adverse effects were observed in the mice treated with the AHR inhibitor, but before the treatment is tested in human volunteers the experiment must be replicated in monkeys.

The study took four years to be completed. Nagela Zanluqui and Carolina Polonio, both PhD candidates at ICB-USP with scholarships from FAPESP, also participated.

Inception

Quintana’s laboratory at Harvard is one of the world’s leading centers in studies of the protein AHR. In an interview given to Agência FAPESP, Quintana said his group discovered some years ago that interferons, proteins produced by immune cells in the inflammatory response to infections, control the activation of AHR.

“Because interferons are central to the antiviral immune response, we postulated – together with Garcia’s group – that AHR might be involved in the suppression of immunity against viruses. We designed anti-AHR therapies and developed nanoparticles and inhibitors for use in the experiments,” Quintana said.

Tests performed in the laboratory and in animals confirmed that viruses activate AHR to suppress the host’s immune response. This may occur when a pathogen infects the liver, triggering release of the tryptophan metabolite kynurenine.

“This metabolite activates AHR, which inhibits the expression of another protein called PML [promyelocytic leukemia protein, very important to the antiviral immune response] and thereby lets the virus replicate more freely in cells,” Peron said.

At the University of Buenos Aires, Garcia led experiments with various cell lines including hepatocytes and neural progenitors, stem cells that have the capacity to differentiate into neuronal and glial cells.

“We treated the cell lines with AHR agonist compounds [which magnify the action of the protein] and AHR antagonists [which inhibit it],” Garcia told Agência FAPESP. “In this manner we confirmed that negative modulation of this receptor inhibits replication of zika. In the same way we demonstrated that positive modulation boosts viral replication in cells.”

Environmental factors

The impact of the 2015 zika epidemic was highly asymmetrical, Garcia said. In some regions and cities, the incidence of the congenital syndrome and microcephaly caused by the virus was much higher than in others. In her view this may be because of environmental factors favoring infection in the worst-hit areas or because their inhabitants were more susceptible. Both factors may also have contributed simultaneously to an intensification of zika’s impact.

“Coincidentally, AHR can be activated by environmental pollutants, and by certain diets or endogenous microbiota. Our next challenge is to rule out or confirm the existence of a link between AHR, polluted or socio-economically degraded environments and heightened virulence of zika,” Garcia said.

The article “AHR is a zika virus host factor and a candidate target for antiviral therapy” can be read at: https://doi.org/10.1038/s41593-020-0664-0.

Journal

Nature Neuroscience

DOI

10.1038/s41593-020-0664-0

UNIVERSITY PARK, Pa. -- In their zeal to promote the importance of climate change as an ecological driver, climate scientists increasingly are ignoring the profound role that indigenous peoples played in fire and vegetation dynamics, not only in the eastern United States but worldwide, according to a Penn State researcher.

"In many locations, evidence shows that indigenous peoples actively managed vast areas and were skilled stewards of the land," said Marc Abrams, professor of forest ecology and physiology. "The historical record is clear, showing that for thousands of years indigenous peoples set frequent fires to manage forests to produce more food for themselves and the wildlife that they hunted, and practiced extensive agriculture."

Responding to an article published earlier this year in a top scientific journal that claimed fires set by Native Americans were rare in southern New England and Long Island, New York, and played minor ecological roles, Abrams said there is significant evidence to the contrary.

In an article published today (July 20) in Nature Sustainability, Abrams, who has been studying the historical use of fire in eastern U.S. forests for nearly four decades, refutes those contentions.

"The palaeoecological view -- based on a science of analyzing pollen and charcoal in lake sediments -- that has arisen over the last few decades, contending that anthropogenic fires were rare and mostly climate-driven, contradicts the proud legacy and heritage of land use by indigenous peoples, worldwide," he said.

In his article, Abrams, the Nancy and John Steimer Professor of Agricultural Sciences in the College of Agricultural Sciences, argues that the authors of the previous paper assumed that the scarcity of charcoal indicated that there had not been burning. But frequent, low-intensity fires do not create the amount of charcoal that intense, crown-level, forest-consuming wildfires do, he pointed out.

"Surface fires set by indigenous people in oak and pine forests, which dominate southern New England, often produced insufficient charcoal to be noticed in the sediment," said Abrams. "The authors of the earlier article did not consider charcoal types, which distinguish between crown and surface fires, and charcoal size -- macro versus micro -- to differentiate local versus regional fires."

Also, lightning in New England could not account for the ignition of so many fires, Abrams argues. In southern New England, lightning-strike density is low and normally is associated with rain events.

"The region lacks dry lightning needed to sustain large fires," he said. "Moreover, lightning storms largely are restricted to the summer when humidity is high and vegetation flammability is low, making them an unlikely ignition source."

Early explorers and colonists of southern New England routinely described open, park-like forests and witnessed, firsthand, Native American vegetation management, Abrams writes in his article, adding that oral history and numerous anthropological studies indicate long-term burning and land-use for thousands of years by indigenous people.

Burning near Native American villages and along their extensive trail systems constitutes large land areas, and fires would have kept burning as long as fuel, weather and terrain allowed, he explained. Following European settlement, these open oak and pine woodlands increasingly became closed by trees that previously were held in check by frequent fire.

The authors of the previous paper also argued that fire should not be used as a present-day management tool, a view that Abrams does not support.

The role of anthropogenic fires is front and center in the long-running climate-disturbance debate, according to Abrams, who notes that fires increased with the rise of human populations. The world would be a very different place without those fires, he contends.

"Surprisingly, the importance of indigenous peoples burning in vegetation-fire dynamics is increasingly downplayed among paleoecologists," he writes. "This applies to locations where lightning-caused fires are rare."

Abrams points out that he is not denying the importance of climate in vegetation and fire dynamics or its role in enhancing the extent of human fires. "However," he writes, "in oak-pine forests of southern New England, Native American populations were high enough, lighting-caused fires rare enough, vegetation flammable enough and the benefits of burning and agriculture great enough for us to have confidence in the importance of historic human land management."