Hexbyte Glen Cove US and Iranian researchers collaborate on Lake Urmia restoration thumbnail

Hexbyte Glen Cove US and Iranian researchers collaborate on Lake Urmia restoration

Hexbyte Glen Cove

Iran’s Lake Urmia — a sister to Utah’s Great Salt Lake — has lost nearly 95 percent of its volume in the span of two decades. Credit: Somayeh Sima

In a rare exchange, scientists and water resources engineers from Iran and Utah are collaborating on a bold scientific study to restore one of the world’s largest saline lakes.

Lake Urmia—a massive salt lake in Iran’s northwest and a sister to Utah’s Great Salt Lake—has lost nearly 95 percent of its volume over the last two decades. As levels drop, salinity spikes, threatening the lake’s brine shrimp population and the flamingos and other bird species that depend on the shrimp for food. Lake levels are so low that at some coastal resorts, tourism boats must be pulled a kilometer (0.6 mile) or more from shore by tractor before reaching suitable depths. In addition, new land bridges are forming in the drying lake bed which allows mainland predators to threaten endangered mammals living in the southern islands. The vast, dry lakebed imposes a growing dust problem for the five million residents who live in the Lake Urmia basin. What’s more, the area’s ecotourism industry has collapsed, and now experts fear an environmental disaster awaits if drastic changes are not made.

“We’re at the tipping point,” said professor and lead author Somayeh Sima of Tarbiat Modares University in Iran. “Every single step matters. We have to take action now.” Sima’s work will be used to update Iran’s $1 billion Lake Urmia Restoration Program. In 2018, she traveled to Utah on a visiting scholarship from the Semnani Family Foundation to collaborate with Utah State University water resources professor David Rosenberg who studies integrated and in Western U.S. river basins, including rivers that feed the Great Salt Lake. Prof. Wayne Wurtsbaugh, Sarah Null, and Karin Kettenring from the USU Quinney College of Natural Resources also collaborated in the limnology and ecology parts of this multidisciplinary research.

The team synthesized 40 years of data to define eight metrics that define the health of Lake Urmia and its many ecosystems. Their findings were published in the latest edition of the Journal of Hydrology: Regional Studies. One key finding shows that setting a target water level will not necessarily solve Lake Urmia’s problems.

“We can’t say that restoring the lake to some magic number will improve the overall situation,” said Rosenberg. “Instead, we need to consider how the lake’s ecosystem services are interconnected and how a varying lake level will impact those systems over time.”

“We have to embrace level variability and focus our restoration efforts where it makes sense,” Sima added. “Restoration is not an easy task. It is everyone’s responsibility, and we’ll need public support to make meaningful change.”

The problems facing Lake Urmia are not unique to Iran. Water levels at the Great Salt Lake are also at their lowest in recent years, and similar problems of land bridges, dust, changes in salinity, and ecological damage have experts concerned.

To promote transparency and reproducibility in science and encourage further collaborations, the researchers published their article (free to readers) and shared their data and code on the HydroShare.org repository.

“This partnership between U.S. and Iranian researchers is valuable because we have so much in common on this topic, said Sima. “Only together can we begin to understand how to solve these problems.”



More information:
Somayeh Sima et al, Managing Lake Urmia, Iran for diverse restoration objectives: Moving beyond a uniform target lake level, Journal of Hydrology: Regional Studies (2021). DOI: 10.1016/j.ejrh.2021.100812

Citation:
US and Iranian researchers collaborate on Lake Urmia restoration (2021, April 23)
retrieved 26 April 2021
from https://phys.org/news/2021-04-iranian-collaborate-lake-urmia.html

Thi

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove Flexible diet may help leaf-eating lemurs resist deforestation thumbnail

Hexbyte Glen Cove Flexible diet may help leaf-eating lemurs resist deforestation

Hexbyte Glen Cove

A new study sequencing the genome of four species of sifakas (Propithecus), a genus of lemurs found in Madagascar’s forests, reveals that these animals’ taste for leaves runs all the way to their genes, which are also more diverse than expected for an endangered species. Credit: Lydia Greene, Duke University

Fruits and veggies are good for you and if you are a lemur, they may even help mitigate the effects of habitat loss.

A new study sequencing the genome of four species of sifakas, a genus of lemurs found only in Madagascar’s forests, reveals that these animals’ taste for leaves runs all the way to their genes, which are also more diverse than expected for an endangered species.

Sifakas are folivores, meaning that the bulk of their diet is composed of leaves. Leaves can be difficult to digest and full of toxic compounds meant to prevent them from being eaten. Unlike our carefully selected spinach, tree leaves also don’t taste great, and are not very nutritious.

Because of that, leaf-eaters typically have all sorts of adaptations, such as a longer with special pouches where bacteria help break down the food.

In a new study appearing April 23 in Science Advances, researchers sequenced genomes from Coquerel’s (Propithecus coquereli), Verreaux’s (P. verreauxi), golden-crowned (P. tattersalli), and diademed (P. diadema) sifakas. The individuals sequenced had been wild-born but were housed at the Duke Lemur Center, with the exception of two Verreaux’s sifakas, one wild and one born in captivity.

These four species are found in different habitats in Madagascar, ranging from arid deciduous forests to rainforests, but share a similar diet.

The genomes showed molecular evidence for adaptations to neutralize and eliminate leaves’ toxic compounds, optimize the absorption of nutrients, and detect bitter tastes. Their genome shows patterns of molecular evolution similar to those found in other distantly related herbivores, such as the colobus monkeys from Central Africa, and domestic cattle.

Yet despite being such fine-tuned leaf-eating machines, sifakas can eat more than just leaves. They eat lots of fruits when those are in season and will also happily munch on flowers.

“Sifakas can take advantage of foods that are higher energy and are more nutrient dense, and can fall back and subsist on leaves in times of scarcity,” said Elaine Guevara, assistant research professor of Evolutionary Anthropology at Duke University and lead author of the study.

This dietary flexibility may have given them an advantage over their strictly leaves-only or fruit-only cousins in the face of threats such as forest fragmentation and disturbance.

A new study sequencing the genome of four species of sifakas (Propithecus), a genus of lemurs found in Madagascar’s forests, reveals that these animals’ taste for leaves runs all the way to their genes, which are also more diverse than expected for an endangered species. Credit: Lydia Greene, Duke University

Indeed, the analysis also showed that sifakas are genetically more diverse than would be expected for a critically on an island of shrinking habitats.

“These animals do seem to have very healthy levels of genetic diversity, which is very surprising,” said Guevara.

Guevara and her team gauged genome heterozygosity, which is a measure of genetic diversity and an indicator of population size. Species at high risk for extinction tend to have only left, and very low heterozygosity.

Sifakas do not follow this pattern and show far higher heterozygosity than other primates or other species of critically endangered mammals. Heterozygous populations tend to be more resilient to threats such as climate change, habitat loss, and new pathogens.

However, sifakas have very long generation times, averaging 17 years, so the loss of genetic diversity may take decades to become obvious. Guevara says that the genetic diversity found in this study may actually reflect how healthy populations were 50 years ago, prior to a drastic increase in deforestation rates in Madagascar.

“Sifakas are still critically endangered, their population numbers are decreasing, and is accelerating drastically,” said Guevara.

There is still room for optimism. By not being picky eaters, sifakas may be less sensitive to deforestation and fragmentation than primates with more restricted diets, allowing them to survive in areas with less-than-pristine forests.

“I’ve seen sifakas at the Lemur Center eat dead pine needles,” said Guevara. “Their diet is really flexible.”

Their greater genetic diversity may therefore mean that there is still hope for sifakas, if their habitats receive and maintain protection and strategic management.

“Sifakas still have a good chance if we act. Our results are all the more reason to do everything we can to help them,” said Guevara.



More information:
“Comparative genomic analysis of sifakas (Propithecus) reveals selection for folivory and high heterozygosity despite endangered status” Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abd2274

Citation:
Flexible diet may help leaf-eating lemurs resist deforestation (2021, April 23)
retrieved 26 April 2021
from https://phys.org/news/2021-04-flexible-diet-leaf-eating-lemurs-resist.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove A more efficient, safer alternative to sourcing copper via bacteria thumbnail

Hexbyte Glen Cove A more efficient, safer alternative to sourcing copper via bacteria

Hexbyte Glen Cove

Credit: Pixabay/CC0 Public Domain

Copper remains one of the single most ubiquitous metals in everyday life. As a conductor of heat and electricity, it is utilized in wires, roofing and plumbing, as well as a catalyst for petrochemical plants, solar and electrical conductors and for a wide range of energy related applications. Subsequently, any method to harvest more of the valuable commodity proves a useful endeavor.

Debora Rodrigues, Ezekiel Cullen Professor of Engineering at the University of Houston Cullen College of Engineering, in collaboration with Francisco C. Robles Hernandez, professor at the UH College of Technology and Ellen Aquino Perpetuo, professor at the University of Sao Paulo, Brazil offered conclusive research for understanding how bacteria found in mines convert toxic copper ions to stable single-atom copper.

In their co-authored paper, “Copper Mining Bacteria: Converting toxic copper ions into a stable single atom copper,” their research demonstrates how copper-resistant bacterium from a copper mine in Brazil convert copper sulfate ions into zero-valent metallic copper.

“The idea of having bacteria in mines is not new, but the unanswered question was: what are they doing in the mines?” Robles said. “By putting the bacteria inside an electronic microscope, we were able to figure out the physics and analyze it. We found out the bacteria were isolating single atom copper. In terms of chemistry, this is extremely difficult to derive. Typically, harsh chemicals are used in order to produce single atoms of any element. This bacterium is creating it naturally that is very impressive.”

As useful as copper is, the process of mining the metal often leads to toxic exposures and challenges on drawing out substantial volume for commercial use. Approximately one billion tons of copper are estimated in global reserves, according to the Copper Development Association Inc., with roughly 12.5 million metric tons per year mined. This aggregates to roughly 65 years of remaining reserves. Part of the supply challenge comes from limited available copper in high concentration in the earth’s crust, but the other challenge is the exposure to and nitrogen dioxide in the copper smelting and to concentrate the metal into useful quantities.

“The novelty of this discovery is that microbes in the environment can easily transform copper sulfate into zero valent single atom copper. This is a breakthrough because the current synthetic process of single atom zerovalent copper is typically not clean, it is labor intensive and expensive,” Rodrigues said.

“The microbes utilize a unique biological pathway with an array of proteins that can extract copper and convert it into single-atom zero-valent copper. The aim of the microbes is to create a less toxic environment for themselves by converting the ionic copper into single-atom copper, but at the same time they make something that is beneficial for us too.”

With a focus in electronic microscopy, Robles examined samples from Rodrigues’ findings in Brazilian and he determined the single atom nature of the copper. Rodrigues and Aquino’s groups further identified the bacterial process for converting copper sulfate to elemental copper—a rare find.

Research results demonstrate this new conversion process as an alternative to produce single of metallic coper is safer, and more efficient versus current methods (i.e. , sputtering and femtosecond laser ablation).

“We have only worked with one bacterium, but that may not be the only one out there that performs a similar function,” Rodrigues concluded. “The next step for this particular research is harvesting the copper from these cells and using it for practical applications.”



More information:
Louise Hase Gracioso et al, Copper mining bacteria: Converting toxic copper ions into a stable single-atom copper, Science Advances (2021). DOI: 10.1126/sciadv.abd9210

Citation:
A more efficient, safer alternative to sourcing copper via bacteria (2021, April 24)
retrieved 25 Apri

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove Out of the cave: French isolation study ends after 40 days (Update) thumbnail

Hexbyte Glen Cove Out of the cave: French isolation study ends after 40 days (Update)

Hexbyte Glen Cove

Members of the French team that participated in the “Deep Time” study, emerge from the Lombrives Cave after 40 days underground in Ussat les Bains, France, Saturday, April 24, 2021. After 40 days in voluntary isolation, 15 people participating in a scientific experiment have emerged from a vast cave in southwestern France. Eight men and seven women lived in the dark, damp depths of the Lombrives cave in the Pyrenees to help researchers understand how people adapt to drastic changes in living conditions and environments. They had no clocks, no sunlight and no contact with the world above. (AP Photo/Renata Brito)

Ever wonder what it would feel like to unplug from a hyperconnected world and hide away in a dark cave for 40 days?

Fifteen people in France did just that, emerging Saturday from a scientific experiment to say that time seemed to pass more slowly in their cavernous underground abode in southwestern France, where they were deprived of clocks and light.

With big smiles on their pale faces, the 15 left their voluntary isolation in the Lombrives cave to a round of applause and basked in the light while wearing special glasses to protect their eyes after so long in the dark.

“It was like pressing pause,” said 33-year-old Marina Lançon, one of the seven female members in the experiment, adding she didn’t feel there was a rush to do anything.

Although she wished she could have stayed in the cave a few days longer, she said she was happy to feel the wind blowing on her face again and hear the birds sing in the trees of the French Pyrénées. And she doesn’t plan to open her smartphone for a few more days, hoping to avoid a “too brutal” return to real life.

For 40 days and 40 nights, the group lived in and explored the cave as part of the Deep Time project. There was no sunlight inside, the temperature was 10 degrees Celsius (50 F) and the relative humidity stood at 100%. The cave dwellers had no contact with the outside world, no updates on the pandemic nor any communications with friends or family.

Members of the French team that participated in the “Deep Time” study pose for a photo after exiting the Lombrives Cave in Ussat les Bains, France, Saturday, April 24, 2021. After 40 days in voluntary isolation, 15 people participating in a scientific experiment have emerged from a vast cave in southwestern France. Eight men and seven women lived in the dark, damp depths of the Lombrives cave in the Pyrenees to help researchers understand how people adapt to drastic changes in living conditions and environments. They had no clocks, no sunlight and no contact with the world above. (AP Photo/Renata Brito)

Scientists at the Human Adaption Institute leading the 1.2 million-euro $1.5 million) “Deep Time” project say the experiment will help them better understand how people adapt to drastic changes in living conditions and environments.

As expected, those in the cave lost their sense of time.

“And here we are! We just left after 40 days … For us it was a real surprise,” said project director Christian Clot, adding for most participants, “in our heads, we had walked into the cave 30 days ago.”

At least one team member estimated the time underground at 23 days.

Johan Francois, 37, a math teacher and sailing instructor, ran 10-kilometer circles in the cave to stay fit. He sometimes had “visceral urges” to leave.

With no daily obligations and no children around, the challenge was “to profit from the present moment without ever thinking about what will happen in one hour, in two hours,” he said.

Members of the French team that participated in the “Deep Time” study, celebrate as they emerge from the Lombrives Cave after 40 days underground in Ussat les Bains, France, Saturday, April 24, 2021.After 40 days in voluntary isolation, 15 people participating in a scientific experiment have emerged from a vast cave in southwestern France. Eight men and seven women lived in the dark, damp depths of the Lombrives cave in the Pyrenees to help researchers understand how people adapt to drastic changes in living conditions and environments. They had no clocks, no sunlight and no contact with the world above. (AP Photo/Renata Brito)

In partnership with labs in France and Switzerland, scientists monitored the 15 member’s sleep patterns, social interactions and behavioral reactions via sensors. One sensor was a tiny thermometer inside a capsule that participants swallowed like a pill. It measured body temperatures and transmitted data to a computer until it was expelled naturally.

The team members followed their biological clocks to know when to wake up, go to sleep and eat. They counted their days not in hours but in sleep cycles.

On Friday, scientists monitoring the participants entered the cave to let the research subjects know they would be coming out soon.

“It’s really interesting to observe how this group synchronizes themselves,” Clot said earlier in a recording from inside the cave. Working together on projects and organizing tasks without being able to set a time to meet was especially challenging, he said.

Members of the French team that participated in the “Deep Time” study, emerge from the Lombrives Cave after 40 days underground in Ussat les Bains, France, Saturday, April 24, 2021. After 40 days in voluntary isolation, 15 people participating in a scientific experiment have emerged from a vast cave in southwestern France. Eight men and seven women lived in the dark, damp depths of the Lombrives cave in the Pyrenees to help researchers understand how people adapt to drastic changes in living conditions and environments. They had no clocks, no sunlight and no contact with the world above. (AP Photo/Renata Brito)

Although the participants looked visibly tired Saturday, two-thirds expressed a desire to remain underground a bit longer in order to finish group projects started during the expedition, Benoit Mauvieux, a chronobiologist involved in the research, told The AP.

“Our future as humans on this planet will evolve,” Clot said after emerging. “We must learn to better understand how our brains are capable of finding new solutions, whatever the situation.”



© 2021 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.

Citation:
Out of the cave: French isolation study ends after 40 days (Update) (2021, April 24)
retrieved 25 April 2021
from https://phys.org/news/2021-04-cave-french-isolation-days.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove California to ban new fracking from 2024 thumbnail

Hexbyte Glen Cove California to ban new fracking from 2024

Hexbyte Glen Cove

California plans to ban new permits for fracking from 2024

California plans to stop issuing new fracking permits by 2024, Governor Gavin Newsom said Friday, as the state looks toward progressively halting fossil fuel extraction in the coming decades.

Hydraulic fracturing, a method of extracting hydrocarbons that is controversial for its impact on the environment, accounts for as much as 17 percent of California’s production, according to industry groups.

“The is real, and we continue to see the signs every day,” Newsom said in a statement.

“As we move to swiftly decarbonize our transportation sector and create a healthier future for our children, I’ve made it clear I don’t see a role for fracking in that future and, similarly, believe that California needs to move beyond oil.”

The state oil and gas regulator will start the process to halt the issuance of new permits by January 2024, he explained, referring to the Department of Conservation’s Geologic Energy Management.

Newsom also instructed the state’s clean air agency to investigate “pathways” to phase out oil extraction by 2045.

That target ties in with California’s efforts to fight , including the goal of being “” for its economy by 2045 and Newsom’s decision to ban the sale of new combustion-engine vehicles by 2035.

The fracking industry boomed between 2000-2010 making the United States the world’s leading oil producer since 2014.

But its environmental and health costs are increasingly well documented: earthquakes, air and near farms as well as leaks of planet-warming methane gas.



© 2021 AFP

Citation:
California to ban new fracking from 2024 (2021, April 24)
retrieved 25 April 2021
from https://phys.org/news/2021-04-california-fracking.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove Citizen science data tracks battle of birds vs bacteria thumbnail

Hexbyte Glen Cove Citizen science data tracks battle of birds vs bacteria

Hexbyte Glen Cove

Male house finch. Credit: Cornell Lab of Ornithology

House finches are locked in a deadly cycle of immunity and new strains of bacterial infection in battling an eye disease that halved their population when it first emerged 25 years ago, according to new research from the Cornell Lab of Ornithology.

House finch causes red, swollen, watery or crusty eyes. Afflicted birds can recover, but may die because they cannot see well enough to find food or avoid predators. The latest analyses, based on the observations of Project FeederWatch participants from eight Northeast states, addresses the long-term impact of the disease on house finch populations and points to the role of the finch in the bird vs. battle.

“We have an escalating arms race,” said Cornell Lab researcher Wesley Hochachka, first author of “Host Population Dynamics in the Face of an Evolving Pathogen,” which published April 5 in the Journal of Animal Ecology. “Finches who become infected but survive acquire some immunity to that version of the bacteria and its predecessors. The bacteria evolve to get around the strengthened finch immunity. Then birds acquire immunity to the latest strain, and the cycle keeps repeating.

The study’s authors believe that acquired immunity—when the immune system creates antibodies in response to an infection—is actually driving the arms race between the birds and the bacteria. They said imperfect acquired immunity, just like imperfect vaccines against human pathogens, creates the conditions needed to favor the proliferation of new strains of the bacteria that can overcome immunity acquired against existing strains of bacteria.

Immunity can also develop through to the house finches, but this would be a relatively slow process, requiring multiple years for genetically novel and resistant finches to become widespread. In contrast, genetic changes to the bacteria can proliferate within hours—so fast that populations of house finches can’t possibly evolve a defense quickly enough.

“We should really pay more attention to the role that acquired immunity can play in the dynamics of disease in any animal,” Hochachka said. “Interactions can be much more complicated when both the host and the disease are able to change rapidly.”

The overall house finch was cut in half during the initial outbreak when the bacteria jumped to finches from poultry in 1994. House finch populations now are mostly stable at their current, lower level.

Hochachka said that’s surprising because typically in other tracked animal diseases, either the animal populations rebound or fluctuate widely following the initial disease outbreak. But he thinks the finch population is not likely to return to pre-disease levels.

The eye disease dynamic has parallels to human health and the use of vaccines to give people acquired immunity to diseases. Here also, imperfect immunity—vaccines that do not provide perfect protection—are believed to accelerate the spread of new strains of pathogens against which vaccines are ineffective.

“The emergence of new diseases is going to keep happening,” Hochachka said. “We just have to develop methods and systems for dealing with it as best we can when a lethal appears.”



More information:
Wesley M. Hochachka et al. Host population dynamics in the face of an evolving pathogen, Journal of Animal Ecology (2021). DOI: 10.1111/1365-2656.13469

Citation:
Citizen science data tracks battle of birds vs bacteria (2021, April 23)
retrieved 24 April 2021
from https://phys.org/news/2021-04-citizen-science-tracks-birds-bacteria.html

Thi

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove Perovskites under pressure: Hot electrons cool faster thumbnail

Hexbyte Glen Cove Perovskites under pressure: Hot electrons cool faster

Hexbyte Glen Cove

Artist impression of ‘hot electrons’ becoming faster under pressure. Hot electrons under pressure get rid of their excess energy faster. Credit: thisillustrations.com

In solar cells, about two third of the energy of sunlight is lost. Half of this loss is due to a process called ‘hot carrier cooling’ where high energy photons lose their excess energy in the form of heat before being converted to electricity. Scientists at AMOLF have found a way to manipulate the speed of this process in perovskites by applying pressure to the material. This paves the way for making perovskites more versatile, not only for use in solar cells but also in a variety of other applications, from lasers to thermoelectric devices. The researchers will publish their study in the Journal of Physical Chemistry Letters on 23 April.

Perovskites are a promising material for future generation solar , because they are made from cheap ingredients and it is easy to change their composition to fit specific needs, like solar cells in any desired color. Researchers in the Hybrid Solar Cells group at AMOLF try to increase the efficiency and lifetime of hybrid semiconductors by uncovering the fundamental properties of perovskites. One of these properties is the speed at which so-called hot cooling occurs, which is also relevant if perovskites are used in other applications.

Hot carrier cooling

In solar cells, the of light that matches the bandgap of the semiconductor is converted into electricity directly. This direct route is not available for photons with a higher energy. These photons generate so-called hot carriers: high-energy electrons (and holes) that have to cool down before they can be harvested in the form of electrical energy. Hot carrier cooling occurs spontaneously: the hot carriers lose their excess energy in the form of heat through scattering until they match the conduction energy level of the semiconductor. Trying to understand this process in perovskites, Ph.D. student Loreta Muscarella encounters various difficulties, one of them being the timescale. She says, “Hot carrier cooling occurs very fast, typically on a timescale of femtoseconds to picoseconds, which makes it hard to manipulate or even investigate the process. We are lucky to have a unique set-up with a Transient Absorption Spectrometer (TAS) in combination with pressure equipment in our group. This allows us to measure the electronic properties of perovskite under external stress a few femtoseconds after shining light onto the material.”

Manipulating with pressure

It was already known that under abundant illumination hot carrier cooling in perovskite semiconductors is much slower than in silicon semiconductors. This makes the investigation of the process much more feasible in perovskite rather than silicon. Muscarella and her colleagues assumed that the speed of the cooling process might be pressure-dependent. “The hot carriers lose their excess energy through vibration and scattering. Applying pressure increases vibrations inside the material, and should thus increase the speed of hot carrier cooling,” she says. “We decided to test this assumption and found that we can indeed manipulate the cooling time with pressure. At 3000 times the process is two to three times faster.”

A solar cell would not be able to operate at such high pressures, but a similar effect can be obtained with internal strain. Muscarella: “We did our experiments with external pressure, but in perovskites it is possible to induce an internal strain by chemically altering the material or its growth, as we have previously shown in our group.”

Cooling speed for different applications

Being able to control the hot carrier cooling speed allows for various other applications of perovskites besides solar cells. “The possibility to design perovskites for specific colors not only makes them very interesting for colored solar cells, but also for lasers or LED technology. In such applications, fast cooling of hot carriers is essential, just like it is in conventional solar cells. Slow cooling on the other hand would make perovskites suitable for thermoelectric devices that convert a temperature difference into electricity. So the possibility to tune the hot carrier cooling speed allows for a whole range of devices that could be made with perovskites,” says Muscarella. She even envisions applying a on the material to make the hot carrier cooling process even slower for a specific type of solar cell.

“Since heat dissipation accounts for almost thirty percent of efficiency loss in solar cells, scientists are looking for ways to harvest the hot carriers before they have cooled. Currently, even the ‘slow’ in perovskites at ambient pressure is still too fast for such so-called hot-carrier . Now, these hot carriers lose their as heat within picoseconds. However, if we could induce a negative strain it might be possible to make the process slow enough to be applied in a working device.”



More information:
Loreta A. Muscarella et al. Accelerated Hot-Carrier Cooling in a MAPbI3 Perovskite by Pressure-Induced Lattice Compression, The Journal of Physical Chemistry Letters, DOI: 10.1021/acs.jpclett.1c00676

Citation:
Perovskites under pressure: Hot electrons cool faster (2021, April 23)
retrieved 24 April 2021

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove Biden administration proposes restoring California's right to set car pollution rules thumbnail

Hexbyte Glen Cove Biden administration proposes restoring California’s right to set car pollution rules

Hexbyte Glen Cove

by Anna M. Phillips

Credit: CC0 Public Domain

The Transportation Department announced Thursday it was withdrawing part of a Trump-era rule that blocked states from setting their own tough car pollution standards, reversing actions by the Trump administration that weakened California’s ability to fight climate change.

The newly proposed rule change, which will be subject to a 30-day comment period, would restore California’s authority to set and greenhouse gas emission standards for cars and SUVs, and to require car companies to sell more electric vehicles.

The agency’s action Thursday suggested the Biden administration was laying the groundwork to eventually reinstate California’s legal waiver, which was granted by the Obama administration under the authority of the 1970 Clean Air Act. The waiver had allowed the state to set stricter auto emission and fuel efficiency rules than even the federal government. That power was widely considered one of the state’s most effective weapons in the fight against and air pollution.

Trump revoked California’s waiver in 2019 shortly before his administration issued a new set of fuel economy and emissions rules that were significantly weaker than the Obama standards. The change also affected the District of Columbia and the 13 states that follow California’s tighter standards.

California and nearly two dozen other states sued the administration, challenging the decision. Major auto manufacturers, including General Motors, Fiat Chrysler and Toyota, joined the lawsuit on Trump’s side in an effort to block the state’s tough fuel economy rules. They quickly abandoned the cause after President Joe Biden was elected.

“The Trump administration should never have challenged California’s legal authority to set our own vehicle emission standards,” Sen. Dianne Feinstein, D-Calif., said in a statement. “The Clean Air Act clearly gives us the right to protect the air Californians breathe and I want to thank the Biden administration for dropping this frivolous challenge.”



©2021 Los Angeles Times.
Distributed by Tribune Content Agency, LLC.

Citation:
Biden administration proposes restoring California’s right to set car pollution rules (2021, April 23)
retrieved 24 April 2021
from https://phys.org/news/2021-04-biden-administration-california-car-pollution.html

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove Experts on violence release report giving recommendations for reducing inappropriate use of force by police thumbnail

Hexbyte Glen Cove Experts on violence release report giving recommendations for reducing inappropriate use of force by police

Hexbyte Glen Cove

Credit: Pixabay/CC0 Public Domain

A new report from the Police Violence Commission of the International Society for Research on Aggression (ISRA) outlines policy and procedural recommendations for reducing use of inappropriate police force from behavioral and social science experts.

The panel of experts, chaired by Paul Boxer, a Professor of Psychology at Rutgers University-Newark whose expertise lies in the development and management of aggressive behavior, especially in , includes leading scholars from across the United States and Germany. SASN Department of Psychology’s Luis Rivera, an associate professor with expertise in implicit bias, and Kaylise Algrim, a doctoral candidate in Boxer’s lab, are among the group.

The report looks at the inappropriate use of force by from the perspective of behavioral and social science inquiry related to aggression, violence, and intergroup relations. Researchers examined use of force in the context of research on modern policing as well as critical race theory and offered five recommendations suggested by contemporary theory and research. The panel’s recommendations are aimed at policymakers, law enforcement administrators, and scholars.

“There is a crisis in the United States and beyond right now with respect to relations between police and the communities they serve,” states Boxer. “Large scale efforts thus far to improve these relations have failed and it is time for a new set of strategies based on behavioral and social science and taking into account the broader environment of systemic bias against minoritized populations, including the de-militarization of the police.”

The five recommendations made by the group include:

  • Implement public policies that can reduce inappropriate use of force directly and through the reduction of broader burdens on the routine activities of police officers.
  • For officers frequently engaged in use-of-force incidents, ensure that best-practice, evidence-based treatments are available and required.
  • Improve and increase the quality and delivery of noncoercive conflict resolution training for all officers, along with police administrative policies and supervision that support alternatives to the use of force, both while scaling back the militarization of .
  • Continue the development and evaluation of multi-component interventions for police departments, but ensure they incorporate evidence-based, field-tested components.
  • Expand research in the behavioral and social sciences aimed at understanding and managing use-of-force by police and reducing its disproportionate impact on minoritized communities and expand funding for these lines of inquiry.

Included in the policy recommendations is more accountability for officers that are found to use excessive force, including ending “qualified immunity” for police as a legal shield against litigation. “The challenge is that any policy can be put on paper,” says Boxer, “but what matters is the accountability—are the policies enforced? Is the enforcement monitored? Is the monitoring evaluated? Are officers who violate policies held accountable?”

Boxer is hopeful that the recent guilty verdict reached in the case of Derek Chauvin, the former Minneapolis police officer who killed George Floyd, will have a positive effect on reducing future use of inappropriate force among police units. “Testimony against Derek Chauvin was provided by the Minneapolis chief of police—this was a big deal as this sort of testimony coming from a high-ranking officer is highly unusual. The chief said that Chauvin violated department policy on protecting the ‘sanctity of life.” This sets a clear bar in Minneapolis. I think the message is pretty clear here, and an easy one for chiefs of police everywhere to understand and convey to their own officers.”

The panel recognizes that a true culture shift will take time, even once policies are implemented, and that inappropriate use of force by police might continue to happen. Boxer suggests that some ways to help lessen the trauma on communities from these incidents is an immediate and clear response from leadership. “Police chiefs and other high-ranking officials could aid in the lessening of trauma for families and communities by taking these stances and clearly communicating these positions very openly and very publicly in the wake of any killing of unarmed civilians by police, and by implementing serious disciplinary action when warranted.”

He adds, “Conversely, officers who successfully de-escalate high-intensity situations could be rewarded for doing so. These sorts of steps could produce immediate impacts on the culture of a department, particularly for departments in higher-crime areas where officers are more frequently exposed to such situations.”

“I hope the Chauvin verdict represents a watershed moment for the police,” said Boxer. “I think there are many communities that enjoy constructive relations with their local police departments. It is clear there are many situations where the police are helpful and valued. But I also think in some cases we probably expect the police to take on too much—and this is where the idea of ‘defund the police’ originates. There have not been high profile calls to eliminate the police altogether, but rather redefine and reorient their work to a more limited scope. Many communities are lacking in enough social and human services, medical and psychiatric services, youth development services that all could work to prevent the sorts of problems that eventually become problems for police. Police should not be asked to take lead roles in handling psychiatric emergencies, for example, and nor should they have to function as ad-hoc case managers for youth having challenges in school or at home.”

“At the same time I hope the Chauvin verdict yields a broader and more effective conversation about system racism in American society and beyond, where the killing of George Floyd (and many other Black men and women) is just one example of many demonstrating the unjust treatment that Black people have received.”

ISRA is is a professional society of scholars and researchers engaged in the scientific study of aggression and violence. The report is available at ISRA’s website and will soon be published in the society’s journal, Aggressive Behavior.



More information:
Report of the Presidential Commission on Police Aggression and

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove Team improves polar direct drive fusion neutron sources for use in laser experiments thumbnail

Hexbyte Glen Cove Team improves polar direct drive fusion neutron sources for use in laser experiments

Hexbyte Glen Cove

This is representative of the capsules used in the Orange and Cutie designs. Credit: Lane Carlsen/General Atomics.

Scientists from Lawrence Livermore National Laboratory (LLNL) and the Laboratory for Laser Energetics (LLE) are working to improve polar direct drive (PDD) neutron sources on the National Ignition Facility (NIF), the world’s most energetic laser.

PDD neutron sources are capsules filled with deuterium-tritium (DT) gas at ambient temperature and shot with robust laser pulses that do not require stringent laser power contrast control or power accuracy. These sources are more time and resource efficient to field on NIF than conventional indirect drive sources that require high-quality cryogenic layers of DT ice. In addition, a lower generated target debris load allows neutron radiation effects experiments to position much closer to the target, creating a stronger neutron radiation field for testing.

The team substantially enhanced the total fusion output and laser-to-fusion energy conversion efficiency for PDD. The team also developed a PDD exploding pusher, or PDXP, platform that has enabled radiation effects testing of recoverable samples at record 14 MeV (Mega electron-volt) neutron fluence levels.

“For over a year and a half after the initial experimental success, this design of PDD was the most efficient way in existence to convert laser energy input into fusion output,” said Charles Yeamans, team lead and first author of a paper that appears in Nuclear Fusion. Co-authors include Elijah Kemp, Zach Walters, Heather Whitley and Brent Blue from LLNL, and Steve Craxton, Patrick McKenty, Emma Garcia and Yujia Yang from LLE.

“Shooting really big lasers at stuff can stimulate fusion reactions like what happens in the sun and other stars and terrestrially in the core of a nuclear detonation,” Yeamans said. “We want to study how the intense radiation fields generated from fusion affect materials, electronics and engineered systems like satellites and airplanes. At NIF we are able to control and position our test objects close to that source.”

Additionally, similar direct drive capsule platforms have many applications on the NIF. With different gas fills they can be used for studies of nuclear reactions of interest to astrophysics and as a source of protons for point backlighting. They also have been used to produce short pulses of high-brightness continuum X-rays for extended X-ray absorption fine structure (EXAFS) studies and for opacity measurements. Additionally, they have been used to make large compressed plasmas for studies of electron-ion energy transfer.

“Overall, a better NIF neutron source design allows us to conduct better radiation effects tests in greater numbers than if we were to rely solely on the mainstream NIF experiments,” he said.

Yeamans said the work developed a valuable addition to the overall radiation effects experimental test capability for the Lab. “It also developed the modeling and simulation capability to understand and improve the neutron source design,” he said. “With this work, we are better able to fulfill this responsibility now and in the future.”

Team success

The work was conducted by a team of designers—scientists who run computer codes that do complicated physics calculations—and experimentalists—engineers who understand and operate the world’s biggest laser, and who determine the best way to test in practice what works in the simulation.

Several of the team members work in both roles, and others specialize as either designer or experimentalist based on what the research team needs. Sixteen days of NIF experimental time spread over more than five years were included in the source development effort, with the three best-performing designs, each conducted during a shot day in 2019, selected for detailed discussion in the publication, said Yeamans.

Heather Whitley, associate program director for High Energy Density Science at LLNL, developed the initial design for a large diameter polar direct drive capsule with Craxton and Garcia from LLE and Warren Garbett from the U.K. Atomic Weapons Establishment.

“This platform is important because it provides high neutron fluences and enables the close positioning of samples near the source for survivability experiments,” Whitley said. “The polar direct drive configuration also provides excellent diagnostic access for other high temperature plasma physics experiments.”

Craxton from LLE helped lead the work of undergraduate students Garcia and Yang and said that the participation of the students has been important to this work. Each student was responsible for calculating the optimized laser beam pointing to achieve uniform implosion of a specific diameter of capsule. This optimization is complicated by the NIF beam entry angles being optimized to drive a cylindrical hohlraum target. McKenty worked closely with Craxton and the rest of the team to determine the ideal pulse shape.

“We went through a whole series of experiments over many years, first to produce neutrons to test NIF neutron diagnostics while NIF was being commissioned,” Craxton said. “These experiments evolved to meet the needs of a wide variety of applications, with the largest targets producing the high yields required for the effects experiments.”

Critical to the success of this effort was the fabrication and developing the proper testing protocols to obtain key data for prescribing safe fielding pressures of these large (2-5 millimeters in diameter), thin wall (approximately 10-30 micrometers) capsules, which are more susceptible to bursting. This was done by target fabrication team mainly at General Atomics (GA) in San Diego, working closely with LLNL’s target fabrication team as well as the above mentioned physics team. Claudia Shuldberg and her team led the work at GA, while Bill Saied and Kelly Youngblood led the target fabrication engineering effort at LLNL.



More information:
C.B. Yeamans et al. High yield polar direct drive fusion neutron sources at the National Ignition Facility, Nuclear Fusion (2021). DOI: 10.1088/1741-4326/abe4e6

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —