Monday, March 02, 2020

Online STEM demonstrations can be as effective as classroom teaching

YouTube has become the go-to for quick tutorials on almost any topic, from how to replace a zipper to how to install a water heater. But could some of the most memorable parts of a STEM course—live demonstrations—be brought to the screen effectively? In a new paper, Harvard researchers show for the first time that research-based online STEM demonstrations not only can teach students more, but can be just as enjoyable.

Researchers hope these findings will help spur the creation of a catalog of free online STEM video demonstrations to supplement lectures at institutions that cannot conduct their own. "We have an incredible group of scientists who present live demos for our students, but very few schools have these dedicated resources," said co-author Logan McCarty, director of science education in the Department of Physics, who oversees Harvard's Lecture Demonstration team. "With YouTube and other online channels, we can share Harvard's technical and pedagogical expertise with the world."

The research was based on previous literature by Kelly Miller, a lecturer in applied physics and co-author with McCarty. The previous article, published in 2013 by Miller and Eric Mazur, Balkanski Professor of Physics and Applied Physics, showed that students often misunderstand lecture demonstrations. They turned to science demos after hearing time and again that they are students' favorite part of the lecture. After all, who could forget a ball levitating on a sound wave or a laser bending into a tank of water?

"Our research suggests that when live demos are unavailable, videos can provide students with an equally effective—or possibly even more effective—learning experience," said co-author Louis Deslauriers, director of science teaching and learning in the Faculty of Arts and Sciences. "Even when live demonstrations are available, it may be helpful to supplement them with high-quality videos."

Their paper in the February issue of Physical Review Physics Education Research was spun into motion by first author Greg Kestin, a preceptor in physics who produces a series with NOVA called "What the Physics?!"

A sample of one of the video demonstrations shown to physics students. “Shoot the Monkey” illustrates gravitational acceleration by releasing a suspended stuffed animal while simultaneously shooting it with a cannon ball. The goal: to determine where to aim in order to hit the falling monkey. Credit: Greg Kestin

"There was already a rich array of findings about how to bring multimedia into education to increase student learning and motivation," said Deslauriers. "What Greg brings which no one else has is a unique combination of expertise in physics, video production, and cognitive psychology of multimedia presentations."

The investigators identified several ingredients in improving learning through online demonstrations. A number of these advantages relied on the filmmaker's ability to set the demonstrations in slow motion, the use of graphics to visualize abstract concepts, and the ability to direct attention to the most important features to prevent information overload.

For the study, they split an introductory physics class into two groups. The first watched a video of a short science demonstration in a classroom setting, while the other group saw the experiment live in the same classroom. They then flipped the groups and performed a second demonstration to reduce bias. Although the demos were virtually identical, the group who first saw the live presentation watched gestures, blackboard illustrations, and physical props, such as large wooden arrows, while the group who viewed video demos followed superimposed graphics, slow-motion video, and animations. In the end, students from both groups who watched the online video scored higher on tests on the material presented, without any reported decrease in enthusiasm.

"Students don't always know where to focus their attention in live demonstrations, even with a chalkboard and props, but in a video format we can highlight and zoom in on particular parts by setting narration at just the right moment to reinforce learning. A video can also present contrasting cases, which is known as a potent learning tool," said Deslauriers.

"Lecture demos have been a core component of STEM courses for over 100 years, but not every school has the resources for them," said Kestin. "We wanted to understand how much students were learning in video demos in the hopes that with the right support we can bring the same excitement to schools everywhere."Study shows students in 'active learning' classrooms learn more than they think

More information: Greg Kestin et al. Comparing the effectiveness of online versus live lecture demonstrations, Physical Review Physics Education Research (2020). DOI: 10.1103/PhysRevPhysEducRes.16.013101

Egg stem cells do not exist, new study shows

by Karolinska Institutet

Researchers at Karolinska Institutet in Sweden have analyzed all cell types in the human ovary and found that the hotly debated "egg stem cells" do not exist. The results, published in Nature Communications, open the way for research on improved methods of treating involuntary childlessness.

The researchers used single-cell analysis to study more than 24,000 cells collected from ovarian cortex samples of 21 patients. They also analyzed cells collected from the ovarian medulla, allowing them to present a complete cell map of the human ovary.

One of the aims of the study was to establish the existence or non-existence of egg stem cells. "The question is controversial since some research has reported that such cells do exist, while other studies indicate the opposite," says Fredrik Lanner, researcher in obstetrics and gynecology at the Department of Clinical Science, Intervention and Technology at Karolinska Institutet, and one of the study's authors.

The question of whether egg stem cells exist affects issues related to fertility treatment, since stem cells have properties that differ from other cells.

"Involuntary childlessness and female fertility are huge fields of research," says co-author Pauliina Damdimopoulou, researcher in obstetrics and gynecology at the same department. "This has been a controversial issue involving the testing of experimental fertility treatments."

The new study substantiates previously reported findings from animal studies—that egg stem cells do not exist. Instead, these are so-called perivascular cells.

The new comprehensive map of ovarian cells can contribute to the development of improved methods of treating female infertility, says Damdimopoulou.

"The lack of knowledge about what a normal ovary looks like has held back developments," she says. "This study now lays the ground on which to produce new methods that focus on the egg cells that already exist in the ovary. This could involve letting egg cells mature in test tubes or perhaps developing artificial ovaries in a lab."

The results of the new study show that the main cell types in the ovary are egg cells, granulosa cells, immune cells, endothelial cells, perivascular cells and stromal cells.

Research could be step toward lab-grown eggs and sperm to treat infertility

More information: "Single-cell analysis of human ovarian cortex identifies distinct cell populations but no oogonial stem cells", Nature Communications (2020). DOI: 10.1038/s41467-020-

Australian summers grow longer due to climate change: study

Australian summers are lengthening by a month or more while winters are getting shorter due to climate change, according to an analysis by a leading think tank released Monday.

The Australia Institute said large swathes of the country were experiencing an additional 31 days of summer temperatures each year compared to the 1950s.

While Sydney was just under the average with an extra 28 hot days a year, Melbourne added 38 warmer days since the middle of the 20th century.

In some regional areas ravaged by bushfires in recent months, such as the New South Wales town of Port Macquarie, residents are now experiencing seven more weeks of typical summer temperatures.

"Temperatures which were considered a regular three-month summer in the 1950s now span from early-to-mid-November all the way to mid-March," Australia Institute climate and energy program director Richie Merzian said.

"Summers have grown longer even in recent years, with the last five years facing summers twice as long as their winters."

Australia's capital, Canberra, lost 35 winter days while the city of Brisbane, in the country's east, lost 31 cooler days.

Merzian said global warming was making the country's summers increasingly dangerous, with less time in winter to carry out bushfire prevention work and extreme heat causing health and economic impacts.

"Extreme heat events are the most fatal of all natural hazards and have been responsible for more deaths in Australia than all other natural hazards put together," he said.

Australia's latest summer heralded a devastating bushfire disaster in which more than 30 people died, thousands of homes were destroyed and at least a billion animals perished.

The crisis led to renewed calls for the country's conservative government to cut the emissions contributing to global warming.

But while Prime Minister Scott Morrison belatedly acknowledged the link between the bushfire disaster and a warming planet, he has been reluctant to reduce the country's reliance on coal.

Renewables accounted for just six percent of Australia's primary energy mix in 2018, according to government figures, while the country is one of the world's largest fossil fuel exporters.

Australia heatwave renews bushfire worries

FEB 26, 2020

Pebble accretion and the early Earth

FEB 23, 2020

Is this mist or haze?

FEB 14, 2020

Meet Thailand's secret weapon in climate change battle

by Dene Chen

Architect Kotchakorn Voraakhom made her name showing how the effects of climate change can be mitigated by ensuring the issue is at the heart of city planning

Bangkok's future hangs in the balance.

Rising sea levels, unchecked development, groundwater extraction, and rapid urban population growth has left millions vulnerable to natural disasters—scientists warn the city itself may not survive the century.

New analysis by the Nestpick 2050 Climate Change City Index says the Thai capital could be hardest hit by global warming.

And while it is not alone facing such a threat—Venice, New Orleans, and Jakarta are predicted to be underwater by 2100—it does have a secret weapon in its battle to negate the impact of a hotter planet: renowned architect Kotchakorn Voraakhom who preaches mindful development over mindless construction.

"We are talking life and death in this situation," says the 39-year-old who is hoping to bring Bangkok back from the brink, as scientists warn extreme weather—flooding and droughts—could ravage the city, leaving as much as 40 percent submerged in the next decade.

Kotchakorn says: "I don't want to face it with fear. At this moment we have a chance to make change... We have to do it right now to show the coming generations that this is possible. It is not about sitting and waiting and doing the same thing."

No one can accuse the Harvard graduate of resting on her laurels: She made her name showing how the effects of climate change can be mitigated by ensuring the issue is at the heart of city planning.

Kotchakorn rails against Bangkok's unchecked development

She and her firm Landprocess created the internationally acclaimed Chulalongkorn University Centenary Park, an 11-acre (4 hectares) space in central Bangkok, which tilts downward at a three-degree angle, allowing rainwater to flow through the flanking grass and wetlands.

Water that's not absorbed by the plants runs down to a pond at the base of the park, where it can be stored and filtered for use during dry spells or released gradually. In cases of severe flooding, the park can hold up to a million gallons of water.

Global rising star

Kotchakorn rails against Bangkok's unchecked development—more than 10 million live in the metropolis packed with skyscrapers, factories, malls and hotels—warning that an "addiction to growth" at all costs is jeopardising its ability to thrive.

"We think about how we're going to have more growth in our annual development... What if we shift the orientation from growth to really consider our actions on the environment, listen to the land more," she says.

"It doesn't mean I am against development but I want it to be very meaningful, very mindful, and at the right pace—so we don't actually kill our future."

Today her ideas have been embraced at home, and abroad—she gave an acclaimed TED talk in 2018, and last year TIME Magazine included her in its "100 Next" list of global rising stars.

But convincing clients, authorities, and other businesses to see the big environmental picture has not been easy in a mega-city obsessed with economic targets and expansion.

Driving change as a woman in a patriarchal society has been an additional challenge, but Kotchakorn insists there is "power" in being different, particularly in an industry dominated by older men offering only "conventional ways of thinking".

Many of her ideas were initially dismissed, but she held firm, explaining: "I feel that was based on their fear. But it's not my fear."

"Women offer different kinds of judgement, different kinds of attitude towards problems... We have to bring that diversity to the table and create better decisions," she adds.

Things must change

A turning point came in 2011, when Thailand endured its worst floods in half a century, which left more than 800 dead nationwide with hundreds of thousands displaced. Bangkok, built on once-marshy land and surrounded by natural waterways, was hard hit.

Then came the World Bank warning that 40 percent of it would be inundated by 2030.

Hailing her late mother as her inspiration, and her 11-year-old daughter as her motivation, Kotchakorn hopes her work will solve problems for generations to come

It was clear then things needed to change, says Voraakhom, who grew up in the capital and says air quality has deteriorated rapidly, as has food quality and security because of the heavy use of pesticides.

In 2018, she created Asia's largest rooftop farm, which mimics the region's famed rice terraces where run-off travels down layers of crops, conserving both water and soil. Winding around the 22,400 square-metre (241,111 square feet) rooftop is a jogging path and a lawn.

Later this year she will unveil plans to transform a vast, unused bridge crossing the Chao Phraya river into a park with bicycle lanes, bringing more green space to a place with precious little of it.

"If you just do a normal building, it's just going to be the same. It's just another building. But if you create (something new), you actually could touch and change their way of living, their way of eating, their way of understanding of sustainability."

Kotchakorn has even greater ambitions for the city she grew up in—she wants to "reclaim" the more than 1,000 canals that snake through Bangkok that are currently used for sewage.

"Canals have so much life, so much potential to be public green space and a skeleton of the whole city," she explains.

Hailing her late mother as her inspiration, and her 11-year-old daughter as her motivation, she hopes her work will solve problems for generations to come.

She says: "Being a mother is really helping to push me to create hope and solutions for the next generation. You see that the things you build will last after your life."

With rising sea levels, Bangkok struggles to stay afloat

Ocean changes almost starved life of oxygen

by University of Exeter

Chemical changes in the oceans more than 800 million years ago almost destroyed the oxygen-rich atmosphere that paved the way for complex life on Earth, new research suggests.

Then, as now, the planet had an "oxidizing" atmosphere, driven by phytoplankton—the "plants" of the ocean—releasing oxygen during photosynthesis.

However, new research from an international team including the University of Exeter and spanning Toulouse, Leeds, London and Nanjing, suggests ocean changes in the early Neoproterozoic era (from one billion to 800 million years ago) may have locked away phosphorus—a vital nutrient for life—limiting phytoplankton growth and oxygen release.

The study suggests the amount of phosphorus available remained "just sufficient" to support the oxidising atmosphere—preventing a return to the "reducing" (oxygen-poor) atmosphere that existed over a billion years earlier.

"Ocean chemistry in this period changed to become 'ferruginous' (rich in iron)," said Dr. Romain Guilbaud, of CNRS (Toulouse).

"We know ocean chemistry affects the cycle of phosphorus, but the impact on phosphorus availability at this time hadn't been investigated until now.

"By analysing ocean sediments, we found that iron minerals were very effective at removing phosphorus from the water."

Phytoplankton growth also boosts atmospheric oxygen because, having split carbon and oxygen and released the oxygen, plants die and their carbon is buried—so it cannot recombine with oxygen to form carbon dioxide.

Despite reductions in photosynthesis and this organic burial of carbon, both due to limited phosphorus, the study suggests oxygen in the atmosphere dropped no lower than 1% of current levels—"just enough" to maintain an oxidizing atmosphere.

"Our observations suggest significant potential variability in atmospheric oxygen concentrations across Earth's 'middle age'," said Professor Tim Lenton, Director of the Global Systems Institute at the University of Exeter.

He added: "One question about the emergence of complex life is why it didn't happen sooner.

"Lack of oxygen and lack of nutrients are two possible reasons, and our study suggests both of these may have been the case in the early Neoproterozoic era.

"In fact, if phosphorus levels in the water had dropped any lower, it could have tipped the world back into a 'reducing' atmosphere suitable for bacteria but not for complex life."

A return to a "reducing" atmosphere would have reversed the Great Oxidation Event, which occurred about 2.5 billion years ago, during which photosynthesis by cyanobacteria in the oceans introduced free oxygen to the atmosphere.

Breathable atmospheres may be more common in the universe than we first thought

More information: Feifei Zhang et al. Extensive marine anoxia associated with the Late Devonian Hangenberg Crisis. March 2020 Earth and Planetary Science Letters 533:115976. DOI: 10.1016/j.epsl.2019.115976

by National Institute for Environmental Studies

Radionuclide levels in freshwater fish differ between lakes and rivers — When it comes to fishing, risk management should be conducted separately for rivers and lakes, for greater accuracy. Credit: NIES

After the Fukushima nuclear power plant accident, managing environmental radionuclide contamination efficiently has become incredibly important. In light of this, a team of scientists from Miharu, Japan, have provided insights that could potentially lead to more accurate environmental risk management in the future. They have shown that the factors affecting contamination of freshwater fish differ between lakes and rivers.

In 2011, when the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident occurred, radioactive materials leaked out into the surrounding land and water bodies, and these became highly contaminated. Consequently, to ensure no imminent risks to the health and safety of the people living in the region, fishing in lakes and rivers in the area was restricted, with no indication of when the ban will be lifted. Scientific efforts to measure the contamination levels of the natural resources of the region, and predict when it will become safe to use them, began soon after the incident and have been ongoing. Research—conducted in the aftermaths of the FDNPP incident and others that came before it, such as the Chernobyl accident—has, so far, determined the biotic and abiotic factors affecting the accumulation of radionuclides in fish. The insights thus gained have helped predict and manage contamination in the environment at Fukushima.

But what remains to be studied is whether these underlying factors differ among ecosystems, and if they do, then how. Addressing this question, a group of scientists from the National Institute for Environmental Studies, Japan, led by Dr. Yumiko Ishii, analyzed the monitoring data of 30 species of fish and aquatic organisms from five rivers and three lakes in Fukushima. This they did two to four years after the FDNPP accident. In their study, published in Journal of Environmental Radioactivity, they statistically correlated radiocesium measurements with a number of biotic and abiotic factors. Radiocesium, particularly cesium-137, has a long half-life, or decay period, of about 30 years, and is the primary contaminant in the area. As Dr. Ishii explains: "After the FDNPP accident, radiocesium has become a major contaminant in Fukushima, and the risk of exposure to its radiation has become a topic of considerable concern."

The factors that the scientists considered were fish characteristics—feeding habit, body size, and habitat; and water chemistry—salinity, total organic carbon, and suspended solids concentration. Their analysis revealed that the factors affecting radiocesium levels in riverine organisms did not necessarily influence radiocesium levels in organisms from the lake. Specifically, suspended solids concentration, total organic carbon, and salinity were significant factors in rivers, but not in lakes. Feeding habits had a major influence in the case of piscivorous fish in lakes, but not in rivers; this was evident from the fact that significant biomagnification of radiocesium (i.e., the increase in its concentration as it travels up the food chain) was observed only in lakes. Lastly, fish size had noticeable influence in both lakes and rivers.

Overall, these findings show that biotic and abiotic factors affecting radionuclide accumulation in fish are clearly dependent on the ecosystem—and they differ between lakes and rivers. The findings of this study could potentially lead to the implementation of better and more efficient environmental disaster response strategies in the future. As Dr. Ishii concludes, "Considering lakes and rivers separately when looking at the effects of radioactive contamination will lead to better and more accurate environmental risk management."

Radioactive tadpoles reveal contamination clues

More information: Yumiko Ishii et al, Different factors determine 137Cs concentration factors of freshwater fish and aquatic organisms in lake and river ecosystems, Journal of Environmental Radioactivity (2019). DOI: 10.1016/j.jenvrad.2019.106102

Provided by National Institute for Environmental Studies

A novel biofuel system for hydrogen production from biomass

by Ulsan National Institute of Science and Technology

A novel technology has been developed for hydrogen production from the process, which involves electron that is produced during the decomposition of biomass such as waste wood. The result produced after biomass decomposition is a high value-added compound, and it is a two-stone technology that improves the efficiency of hydrogen production.

A research team, led by Professor Jungki Ryu in the School of Energy and Chemical Engineering at UNIST has presented a new biofuel system that uses lignin found in biomass for the production of hydrogen. The system decomposes lignin with a molybdenum (Mo) catalyst to produce high value-added compounds, and the electrons extracted in the process effectively produce hydrogen.

An eco-friendly way of producing hydrogen is the electrolysis of water (H2O). The voltage is applied to the water to produce hydrogen and oxygen at the same time. However, in the currently reported technology, the oxygen generation reaction (OER) is slow and complicated, and hydrogen production efficiency is low. This is because hydrogen gas (H2) is produced by hydrogen ions (H+) as electrons, because these electrons come from the oxygen evolution reaction.

Through the study, Professor Ryu and his research team have developed a new biofuel system that uses lignin as an electron donor in a way to reduce the overall inefficiency of the oxygen evolution reaction (OER). This is the principle of using molybdenum-based inexpensive metal catalysts (PMA) to break down lignin at low temperatures, and extract the electrons produced in the process to produce hydrogen. The new device has been designed to move electrons from lignin, along the wire to the electrode where the hydrogen evolution reaction (HER) occurs.

"With this new system, we can produce hydrogen with less energy (overvoltage) than conventional water electrolysis, as there is no need for oxygen reactions, requiring high energy and precious metal catalysts," says Hyeonmyeong Oh (Combined M.S/Ph.D. of Energy and Chemical Engineering, UNIST), the first author of the study. "Conventional methods require more than 1.5 volts, but the new system was capable of producing hydrogen at a much lower potential (0.95 volts)."

In addition, vanillin or carbon monoxide (CO), which are produced via lignin breakdown is very useful substance for various industrial processes. "Lignin, the second most naturally abundant biomass, is difficult to decompose. However, using molybdenum-based catalysts (PMA) it was easily degraded at low temperatures," says Research Assistant Professor Yuri Choi, the co-author of the study.

"The new biofuel system is a technology that produces hydrogen and valuable chemicals using cheap catalysts and low voltages instead of expensive catalysts such as platinum (Pt)," says Professor Ryu. "Our work is also significant, as it presents a new way to replace oxygen-producing reactions in the electrolysis of water."

The findings of this research have been published in ACS Catalysis on January 3, 2020.

Novel biocatalytic system turns waste biomass into value-added chemicals

More information: Hyeonmyeong Oh et al. Phosphomolybdic Acid as a Catalyst for Oxidative Valorization of Biomass and Its Application as an Alternative Electron Source, ACS Catalysis (2020). DOI: 10.1021/acscatal.9b04099

Soil life thrives between oil palm fronds

by University of Göttingen MARCH 2, 2020

Dr Valentyna Krashevska collecting samples of organisms from above the ground for analysis. The team collected over 55,000 living organisms including ants, worms, larvae, millipedes, mites, nematodes and single-celled microorganisms from six different microhabitats. Credit: V Krashevska, University of Göttingen

The threat to insects and other small creatures from rainforest clearance and the consequences for the environment in tropical regions are recognised. What has not been studied so far is whether, and how, the oil palm plantations are able to sustain the populations of tiny below-ground animals that work to keep the soil healthy. In a new study led by the University of Göttingen, scientists have discovered high levels of biological activity in regions above ground level that may serve as oases for soil organisms. They identified that the suspended soil in the gaps where the frond grows out of the palm trunk may in fact provide novel microhabitats where soil creatures can thrive. The research was published in Frontiers in Ecology and the Environment.

The rapid expansion of oil palm plantations throughout Southeast Asia due to increasing global food demand has knock-on effects for the environment. Rainforests may be cleared resulting in major losses of soil structure, fertility and biodiversity. In the soil, many creatures are important for ecosystem functions: making nutrients available, forming soil structures, and providing other services such as decomposition, pollination and pest-control. To find out about the biological activity in soil in oil palm plantations, researchers from the University of Göttingen examined soil communities in six different microhabitats in a 16-year-old oil palm plantation in Sumatra, Indonesia. Scientists from the Collaborative Research Centre EFForTS (Ecological and Socioeconomic Functions of Tropical Lowland Rainforest Transformation Systems) collected 9,205 individuals of macrofauna (earthworms and large arthropods such as ants, fly larvae and millipedes), 40,229 of mesofauna (small arthropods such as springtails and mites), 2,895 nematodes, and 4,467 testate amoebae (single-celled microorganisms that have a protective shell around them).

"Since many oil palm plantations may be with us to stay, it is imperative to get a better understanding of soil biodiversity across microhabitats," explains Dr. Anton Potapov from the University of Göttingen. "This will help farmers and plantation-owners to develop more sustainable methods that can preserve ecosystem functioning." One of the microhabitats the researchers studied is formed from the accumulation of dead leaves and other detritus in the gaps at the base of palm fronds. The detritus forms soil-filled crevices suspended above the ground, which make little corners and recesses for soil life. The scientists' analysis showed there were far more active soil dwellers in these suspended soils than below ground.

"It is important to realize that high activity in the suspended soil does not compensate for the degradation of soil below ground," adds Dr. Valentyna Krashevska. "But now we can take advantage of this knowledge and better preserve suspended soil during plantation management, which may partly offset the damage caused by oil palm agriculture to soil-borne processes and biodiversity."

Moss and detritus collects in the axils of cut palm fronds forming pockets of suspended soil which support many soil organisms. Credit: V Krashevska, University of Göttingen

Explore further

Preparing land for palm oil causes most climate damage
More information: Anton Potapov et al, Aboveground soil supports high levels of biological activity in oil palm plantations, Frontiers in Ecology and the Environment (2020). DOI: 10.1002/fee.2174

Journal information: Frontiers in Ecology and the Environment

Emerging Threats to Human Health from Global Environmental Change

Annual Review of Environment and Resources

Vol. 34:223-252 (Volume publication date 21 November 2009)

https://doi.org/10.1146/annurev.environ.033108.102650

Samuel S. Myersand Jonathan A. Patz

https://www.annualreviews.org/doi/full/10.1146/annurev.environ.033108.102650#f1

Abstract

Large-scale anthropogenic changes to the natural environment, including land-use change, climate change, and the deterioration of ecosystem services, are all accelerating. These changes are interacting to generate five major emerging public health threats that endanger the health and well-being of hundreds of millions of people. These threats include increasing exposure to infectious disease, water scarcity, food scarcity, natural disasters, and population displacement. Taken together, they may represent the greatest public health challenge humanity has faced. There is an urgent need to improve our understanding of the dynamics of each of these threats: the complex interplay of factors that generate them, the characteristics of populations that make them particularly vulnerable, and the identification of which populations are at greatest risk from each of these threats. Such improved understanding would be the basis for stepped-up efforts at modeling and mapping global vulnerability to each of these threats. It would also help natural resource managers and policy makers to estimate the health impacts associated with their decisions and would allow aid organizations to target their resources more effectively.

Links Among Human Health, Animal Health, and Ecosystem Health

Annual Review of Public Health

Vol. 34:189-204 (Volume publication date March 2013)

First published online as a Review in Advance on January 16, 2013

https://doi.org/10.1146/annurev-publhealth-031912-114426

Peter Rabinowitz1 and Lisa Conti2

Abstract

In the face of growing world human and animal populations and rapid environmental change, the linkages between human, animal, and environmental health are becoming more evident. Because animals and humans have shared risk to health from changing environments, it seems logical to expand the perspective of public health beyond a single species to detect and manage emerging public health threats. Mitigating the effects of climate change, emerging pathogens, toxicant releases, and changes in the built environment requires a retooling of global public health resources and capabilities across multiple species. Furthermore, human and animal health professionals must overcome specific barriers to interprofessional collaboration to implement needed health strategies. This review outlines the relationships between human, animal, and ecosystem health and the public health challenges and opportunities that these links present.

https://www.annualreviews.org/doi/abs/10.1146/annurev-publhealth-031912-114426?utm_source=TrendMD_Collection&utm_medium=cpc&utm_campaign=Understanding_Health_Equity&utm_content=Climate

Rethinking 'tipping points' in ecosystems and beyond

by Jenna Marshall, Santa Fe Institute

When a grassland becomes a desert, or a clearwater lake shifts to turbid, the consequences can be devastating for the species that inhabit them. These abrupt environmental changes, known as regime shifts, are the subject of new research in Nature Ecology & Evolution which shows how small environmental changes trigger slow evolutionary processes that eventually precipitate collapse.

Until now, research into regime shifts has focused on critical environmental thresholds, or "tipping points," in external conditions—eg when crossing a certain temperature threshold triggers a sudden shift to desertification. But the new model by Catalina Chaparro-Pedraza and SFI External Professor André de Roos, both at the University of Amsterdam, reveals how a small change in the external environment, with little immediate impact, can induce slow evolutionary changes in the species that inhabit the system. After what the researchers call a "considerable delay," wherein species slowly evolve a new trait or behavior over generations, the regime shift manifests as a delayed reaction.

"Instead of looking for a straightforward relationship between environmental tipping points and ecosystemic collapse, our work brings evolution into the picture," Chaparro-Pedraza explains. "Even though the outcome is the same, we think it's critically important to map out different paths that lead to regime shifts so we can predict and eventually prevent them."

In their model, the researchers demonstrate how these evolution-induced, delayed regime shifts arise in communities of salmon. At different stages of their lives, salmon live in freshwater and marine ecosystems, which both have entirely different biological communities. When a slight change in the marine environment reduces the mortality exposure of the saltwater salmon population, the immediate effects are minor. However, it initiates an evolutionary process that slowly drives individual character traits, like the optimal body size for migrating from the river to an open ocean, to a critical threshold where a regime shift occurs. Remarkably, this regime shift produces dramatic changes in community composition in both the freshwater and marine communities simultaneously, even though nothing changed in the environmental conditions of the freshwater community.

Understanding the role of evolutionary processes in regime shifts could also shed light on other complex, interdependent systems. De Roos and Chaparro-Pedraza also examined data from the 2008 financial crisis, which, according to de Roos, "seem pretty much in line with the adaptation-induced regime shift we report in this paper." In this example, the 2008 crash can be seen as the delayed regime shift. The deregulation of the financial system in the 1970s and 1980s would be the environmental change with a negligible immediate effect, and the documented trend of banks changing their debt-to-asset ratio would be analogous to the evolutionary process triggered by the environmental change.

"Regime shifts don't just happen in ecosystems," says de Roos. "They also appear in systems like stock markets. Our model shows the evolutionary mechanism by which a sudden change—like an ecosystem or financial collapse—may be the result of a small environmental change in the distant past."

Mathematical models provide a snapshot of the human gut microbial community

More information: P. Catalina Chaparro-Pedraza et al. Ecological changes with minor effect initiate evolution to delayed regime shifts, Nature Ecology & Evolution (2020). DOI: 10.1038/s41559-020-1110-0

Coronavirus: Domestic livestock strains are commonplace

by Texas A&M University

Coronavirus: Human strain causes fear, but domestic livestock strains are routine — Strains of coronavirus can occur annually in domestic cattle herds. Credit: Texas A&M AgriLife photo by Kay Ledbetter

Many people are hearing about coronavirus for the first time as COVID-19 affecting humans causes concern all across the world. But coronaviruses are not new to livestock and poultry producers, according to a Texas A&M AgriLife veterinary epidemiologist.

According to the Centers for Disease Control and Prevention, common human coronaviruses usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. Most people get infected with one or more of these viruses at some point in their lives.

But the CDC is now responding to an outbreak of respiratory disease caused by a novel or new coronavirus that was first detected in Wuhan City, Hubei Province, China.

"Coronavirus is a common virus in livestock herds and poultry flocks seen routinely worldwide," said Heather Simmons, DVM, Institute for Infectious Animal Diseases, IIAD, associate director as well as Texas A&M AgriLife Extension Service's associate department head and extension program leader for Veterinary Medical Extension. IIAD is a member of the Texas A&M University System and Texas A&M AgriLife Research.

Wildlife in China may be human strain carriers

"In wildlife, bats are known to carry over 100 different strains of coronavirus, and wild civets are the source of the coronavirus that causes SARS (Severe Acute Respiratory Syndrome), first reported in China in 2002-2003," Simmons said. "Although our understanding is still limited, wild pangolins (a scaly anteater) sold at live markets may be associated with the recently reported coronavirus outbreak in China."

Bats, civets and pangolins are all commonly sold at live markets in China, she said. Coronaviruses from wildlife are dangerous since they have the potential to mutate, adapt and spill over to new species, including humans.

"That is the concern now, this new strain of coronavirus has emerged to cause disease in humans," Simmons said. "It is important to create an understanding of the difference between coronaviruses occurring in domestic livestock and poultry compared to coronaviruses that spill over from wildlife to humans."

Coronavirus in domestic livestock doesn't jump to humans

Simmons said, to date, the coronaviruses in livestock are not considered reportable diseases because their main effect is as an economic burden to livestock producers.

They are known to occur worldwide annually, with some of the most common coronaviruses found in production animals to include the scours and winter dysentery in beef and dairy cattle, porcine respiratory coronavirus in swine and avian infectious bronchitis in poultry.

The World Health Organization has reported that while another coronavirus, MERS-CoV, is known to be transmitted from dromedary camels to humans, other coronaviruses circulating in domestic animals have not yet infected humans.

"That's what is very important to understand at this time," Simmons said. "We have been dealing with these diseases for a long time but as of yet, we have not seen cases worldwide transmitted from livestock to humans or vice versa."

What does coronavirus look like in livestock?

While coronaviruses have a high morbidity, or rate of illness, in livestock and poultry they are generally considered to have low mortality, rate of death, Simmons said. Coronaviruses will affect either the respiratory system or the gastrointestinal system, depending on the species and the age of the animal.

Coronavirus in cattle

In calves, diarrhea commonly occurs in animals under three weeks of age due to a lack of obtaining antibodies when the calf does not get enough colostrum from the mother in order to build up immunity. Clinical signs include severe dehydration and diarrhea. The severity of the clinical signs depends on the age of the calf and their immune status. This is often seen by producers in the winter months as the virus is more stable in cold weather. The second clinical syndrome, winter dysentery is found in adult cattle. Clinical signs include bloody diarrhea with decreased mild production, loss of appetite with some respiratory signs. Bovine coronaviruses can also cause mild respiratory disease or pneumonia in calves up to six months. The virus is shed in the environment through nasal secretions and through feces.

Coronavirus in swine

There are multiple coronaviruses that affect swine. Like cattle, they affect the respiratory or gastrointestinal tract. In sows and piglets, porcine respiratory coronavirus usually presents with no clinical signs. If clinical signs do occur, it may be a transient cough within the herd and spread of this disease occurs through aerosolized methods.

Coronavirus in poultry

Infectious bronchitis virus, or IBV, is a rapidly spreading respiratory disease in young chicks. Clinical signs in laying hens include reduced production, eggshell abnormalities and decreased internal egg quality.

How to treat

Livestock producers should consult with a veterinarian for treatment, Simmons said. Treatment in livestock herds and poultry flocks typically includes supportive therapy of fluids. Antibiotics are not indicated for viral infections but may be used if a secondary bacterial infection occurs.

More information can be found through the Texas A&M AgriLife Extension Disaster Education Network.

Are you in danger of catching the coronavirus? 5 questions answered

Provided by Texas A&M University

LA REVUE GAUCHE - Left Comment