The researchers studied ten agricultural landscapes near Göttingen, each containing three winter wheat fields: one organic field, one conventional field with flower strips, and one conventional field without flower strips. For two years, the abundance of wild bees was recorded at the edges of each of these thirty fields. The results showed that a simple comparison of the data sampled at specific sites could lead to the conclusion that conventional fields with strips of flowers might attract many more bees than organic fields but this is not the full story.

“When we looked more closely, this did not give us a complete picture because it did not take into account that flower strips only cover about five percent of conventional fields which has significantly fewer bees overall than the organic farmland,” explains Professor Teja Tscharntke, Department of Agroecology at Göttingen University. Dr Péter Batáry, group leader at the Centre for Organic Research in Vácrátót, Hungary goes onto say: “In short, organic farming, which typically has more wild plants than conventional fields, is actually more successful than conventional fields with flower strips in promoting bees.”

The missing piece of the jigsaw is the fact that fields of grain in organic farming yield only half the harvest of conventional farming. When the loss in wheat yield is taken into account, a ten-hectare area of organic farmland should be compared to five hectares of conventional farmland plus five hectares of flower strips, which would lead to 3.5 times more bees but the same yield. In this scenario, organic farming would not be the best way to support wild bees.

“These data and considerations show that different benchmarks and criteria should be taken into account when evaluating agri-environmental measures. It is only when we take into account the area along with the yield together with the type of farming that we can achieve a balanced understanding of the ecological and economic effectiveness of environmental measures,” the authors say.

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Materials provided by University of Göttingen. Note: Content may be edited for style and length.

Led by Angel Yanagihara, associate research professor at the UH Manoa School of Ocean and Earth Science and Technology (SOEST) and the John A. Burns School of Medicine, researchers at the UH at Manoa have been carefully tracking local box jellies for over 20 years. While the monthly shoreline aggregations are understood to occur like clockwork 8-10 days after each full moon, with jelly forecasts included on the local news, mysteries have remained: Why are they appearing at this particular part of the lunar cycle? Where do these box jellies come from and where are they found the rest of the lunar cycle? Why has this become a monthly problem in only the last 30 years?

With the new study, the team provided in-depth answers based upon cutting-edge oceanographic approaches including nightlong off shore vessel tracking, computer modeling of local currents and side scan sonar, as well as fundamental field ecology methods and anatomical microscopy.

The senior scientist team of Yanagihara and SOEST oceanography professor Margaret McManus conceived of and began this collaborative study ten years ago starting from monthly box jelly census data collected by the Yanagihara Lab from 1997 to the present.

“We found that the dangerous monthly shoreline appearance of the Hawaiian Box Jellyfish, correlates with the specific nights of the lunar month — referred to as Kaloa in the Hawaiian calendar — with a critical number of hours of darkness after sunset and before moonrise,” said Yanagihara. “We also discovered that all the box jellies comprising the shoreline aggregation were actively spawning.”

Based on studies of thousands of beached box jellies, Yanagihara found that the gonads were all replete with gametes or freshly spent — meaning they were nearshore to reproduce.

“The period of the lunar cycle with a key number of hours of darkness or the ‘absence of light’ cues mature animals to specifically swim to the shore line to spawn,” said Yanagihara. “Further, as divers tracking the migration in the water, we faced a strong south easterly (Diamond Head) current that the box jellies swam successfully perpendicular to but, we divers with tanks and big cameras could not. Their swimming speed and power was impressive!”

With McManus’ oceanographic analysis, the researchers hypothesize that jellies are in the lee of Diamond Head Crater for the rest of the lunar cycle, benefiting from the shelter and food provided by the persistent eddy in the study area, which appears to be the “source point” for the jellyfish or where the box jellies come from.

The UH scientists are addressing issues of importance and concern to residents and tourists alike who enjoy Hawai’i’s coastal waters as well as of great importance to other tropical islands with local populations of this same species Alatina alata. While there are over 40 species of box jellies world wide, Alatina alata is the only species that exhibits this clockwork lunar spawning migration behavior. The team also studied Alatina alata migrations in Saipan, CMNI and Puerto Rico and Key West, FL. This research revealed the unique life cycle involving specific shoreline bathymetry features which support persistent anticyclonic eddy features as well as the lunar trigger for spawning and will allow the team to further investigate other O’ahu locations where box jellies have not been observed historically but have now become more common such as Pupukea and Kailua.

“This work is very important to the State in terms of planning and tourism as well as improved signage, public awareness and dissemination of evidence-based jellyfish sting care,” said Yanagihara.

In the future, the team hopes to continue these studies to model other offshore bay features adjacent to box jelly beaching events and to track population numbers which can become emerging public health concerns for ocean swimmers and beach goers. Specifically, research efforts are being designed to inform and predict, as well as, to help guide policies to restore food web balance to keep box jelly numbers in check in Hawai’i and other tropical localities where Alatina alata also represent a concern for beach goers.

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Materials provided by University of Hawaii at Manoa. Original written by Marcie Grabowski. Note: Content may be edited for style and length.

Producing the extraordinary bursts in space are celestial bodies such as neutron, or collapsed, stars called magnetars (magnet + star) enclosed in extreme magnetic fields. These fields are so strong that they turn the vacuum in space into an exotic plasma composed of matter and anti-matter in the form of pairs of negatively charged electrons and positively charged positrons, according to quantum electrodynamic (QED) theory. Emissions from these pairs are believed to be responsible for the powerful fast radio bursts.

Pair plasma

The matter-antimatter plasma, called “pair plasma,” stands in contrast to the usual plasma that fuels fusion reactions and makes up 99% of the visible universe. This plasma consists of matter only in the form of electrons and vastly higher-mass atomic nuclei, or ions. The electron-positron plasmas are composed of equal mass but oppositely charged particles that are subject to annihilation and creation. Such plasmas can exhibit quite different collective behavior.

“Our laboratory simulation is a small-scale analog of a magnetar environment,” said physicist Kenan Qu of the Princeton Department of Astrophysical Sciences. “This allows us to analyze QED pair plasmas,” said Qu, first author of a study showcased in Physics of Plasmas as a Scilight, or science highlight, and also first author of a paper in Physical Review Letters that the present paper expands on.

“Rather than simulating a strong magnetic field, we use a strong laser,” Qu said. “It converts energy into pair plasma through what are called QED cascades. The pair plasma then shifts the laser pulse to a higher frequency,” he said. “The exciting result demonstrates the prospects for creating and observing QED pair plasma in laboratories and enabling experiments to verify theories about fast radio bursts.”

Laboratory-produced pair plasmas have previously been created, noted physicist Nat Fisch, a professor of astrophysical sciences at Princeton University and associate director for academic affairs at PPPL who serves as principle investigator for this research. “And we think we know what laws govern their collective behavior,” Fisch said. “But until we actually produce a pair plasma in the laboratory that exhibits collective phenomena that we can probe, we cannot be absolutely sure of that.

Collective behavior

“The problem is that collective behavior in pair plasmas is notoriously hard to observe,” he added. “Thus, a major step for us was to think of this as a joint production-observation problem, recognizing that a great method of observation relaxes the conditions on what must be produced and in turn leads us to a more practicable user facility.”

The unique simulation the paper proposes creates high-density QED pair plasma by colliding the laser with a dense electron beam travelling near the speed of light. This approach is cost-efficient when compared with the commonly proposed method of colliding ultra-strong lasers to produce the QED cascades. The approach also slows the movement of plasma particles, thereby allowing stronger collective effects.

“No lasers are strong enough to achieve this today and building them could cost billions of dollars,” Qu said. “Our approach strongly supports using an electron beam accelerator and a moderately strong laser to achieve QED pair plasma. The implication of our study is that supporting this approach could save a lot of money.”

Currently underway are preparations for testing the simulation with a new round of laser and electron experiments at SLAC. “In a sense what we are doing here is the starting point of the cascade that produces radio bursts,” said Sebastian Meuren, a SLAC researcher and former postdoctoral visiting fellow at Princeton University who coauthored the two papers with Qu and Fisch.

Evolving experiment

“If we could observe something like a radio burst in the laboratory that would be extremely exciting,” Meuren said. “But the first part is just to observe the scattering of the electron beams and once we do that we’ll improve the laser intensity to get to higher densities to actually see the electron-positron pairs. The idea is that our experiment will evolve over the next two years or so.”

The overall goal of this research is understanding how bodies like magnetars create pair plasma and what new physics associated with fast radio bursts are brought about, Qu said. “These are the central questions we are interested in.”

This joint work was supported by National Nuclear Security Agency (NNSA) grants awarded to Princeton University through the Department of Astrophysical Sciences and by DOE grants awarded to Stanford University.

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Materials provided by DOE/Princeton Plasma Physics Laboratory. Original written by John Greenwald. Note: Content may be edited for style and length.

Now researchers at MIT have been able to study exactly what happens as these crystal grains form during an extreme deformation process, at the tiniest scales, down to a few nanometers across. The new findings could lead to improved ways of processing to produce better, more consistent properties such as hardness and toughness.

The new findings, made possible by detailed analysis of images from a suite of powerful imaging systems, are reported today in the journal Nature Materials, in a paper by former MIT postdoc Ahmed Tiamiyu (now assistant professor at the University of Calgary); MIT professors Christopher Schuh, Keith Nelson, and James LeBeau; former student Edward Pang; and current student Xi Chen.

“In the process of making a metal, you are endowing it with a certain structure, and that structure will dictate its properties in service,” Schuh says. In general, the smaller the grain size, the stronger the resulting metal. Striving to improve strength and toughness by making the grain sizes smaller “has been an overarching theme in all of metallurgy, in all metals, for the past 80 years,” he says.

Metallurgists have long applied a variety of empirically developed methods for reducing the sizes of the grains in a piece of solid metal, generally by imparting various kinds of strain through deforming it in one way or another. But it’s not easy to make these grains smaller.

The primary method is called recrystallization, in which the metal is deformed and heated. This creates many small defects throughout the piece, which are “highly disordered and all over the place,” says Schuh, who is the Danae and Vasilis Salapatas Professor of Metallurgy.

When the metal is deformed and heated, then all those defects can spontaneously form the nuclei of new crystals. “You go from this messy soup of defects to freshly new nucleated crystals. And because they’re freshly nucleated, they start very small,” leading to a structure with much smaller grains, Schuh explains.

What’s unique about the new work, he says, is determining how this process takes place at very high speed and the smallest scales. Whereas typical metal-forming processes like forging or sheet rolling, may be quite fast, this new analysis looks at processes that are “several orders of magnitude faster,” Schuh says.

“We use a laser to launch metal particles at supersonic speeds. To say it happens in the blink of an eye would be an incredible understatement, because you could do thousands of these in the blink of an eye,” says Schuh.

Such a high-speed process is not just a laboratory curiosity, he says. “There are industrial processes where things do happen at that speed.” These include high-speed machining; high-energy milling of metal powder; and a method called cold spray, for forming coatings. In their experiments, “we’ve tried to understand that recrystallization process under those very extreme rates, and because the rates are so high, no one has really been able to dig in there and look systematically at that process before,” he says.

Using a laser-based system to shoot 10-micrometer particles at a surface, Tiamiyu, who carried out the experiments, “could shoot these particles one at a time, and really measure how fast they are going and how hard they hit,” Schuh says. Shooting the particles at ever-faster speeds, he would then cut them open to see how the grain structure evolved, down to the nanometer scale, using a variety of sophisticated microscopy techniques at the MIT.nano facility, in collaboration with microscopy specialists.

The result was the discovery of what Schuh says is a “novel pathway” by which grains were forming down to the nanometer scale. The new pathway, which they call nano-twinning assisted recrystallization, is a variation of a known phenomenon in metals called twinning, a particular kind of defect in which part of the crystalline structure flips its orientation. It’s a “mirror symmetry flip, and you end up getting these stripey patterns where the metal flips its orientation and flips back again, like a herringbone pattern,” he says. The team found that the higher the rate of these impacts, the more this process took place, leading to ever smaller grains as those nanoscale “twins” broke up into new crystal grains.

In the experiments they did using copper, the process of bombarding the surface with these tiny particles at high speed could increase the metal’s strength about tenfold. “This is not a small change in properties,” Schuh says, and that result is not surprising since it’s an extension of the known effect of hardening that comes from the hammer blows of ordinary forging. “This is sort of a hyper-forging type of phenomenon that we’re talking about.”

In the experiments, they were able to apply a wide range of imaging and measurements to the exact same particles and impact sites, Schuh says: “So, we end up getting a multimodal view. We get different lenses on the same exact region and material, and when you put all that together, you have just a richness of quantitative detail about what’s going on that a single technique alone wouldn’t provide.”

Because the new findings provide guidance about the degree of deformation needed, how fast that deformation takes place, and the temperatures to use for maximum effect for any given specific metals or processing methods, they can be directly applied right away to real-world metals production, Tiamiyu says. The graphs they produced from the experimental work should be generally applicable. “They’re not just hypothetical lines,” Tiamiyu says. For any given metals or alloys, “if you’re trying to determine if nanograins will form, if you have the parameters, just slot it in there” into the formulas they developed, and the results should show what kind of grain structure can be expected from given rates of impact and given temperatures.

The research was supported by the U.S. Department of Energy, the Office of Naval Research, and the Natural Sciences and Engineering Research Council of Canada.

The team combined genetic and biochemical studies to show how freshwater cyanobacteria produce the potent neurotoxin called guanitoxin. This discovery revealed that guanitoxin-producing cyanobacteria are more prevalent than originally known in the United States, opening the possibility for new molecular diagnostic testing to better inform and protect the public from this natural freshwater toxin. Findings were described in a paper published in the Journal of the American Chemical Society on May 18, 2022.

The paper also “shows guanitoxin being produced in freshwater bodies that have undergone past very toxic events,” said study lead author Stella Lima, a former PhD student at the University of São Paulo and visiting scholar at Scripps Oceanography.

Guanitoxin is one of the most potent neurotoxins made by cyanobacteria that actually has a similar mechanism of action to pesticides and chemical warfare agents, said Timothy Fallon, a Scripps postdoctoral scientist in the laboratory of Scripps marine chemical biologist Bradley Moore, where Lima was a visiting scholar.

Harmful algal blooms (HABs) form in lakes and ponds when cyanobacteria, otherwise known as blue-green algae, become abundant. These freshwater HABs produce different cyanotoxins, which can harm nearby animals and people. Depending on the cyanotoxin involved, exposed people exhibit symptoms such as stomach pain, headache, vomiting, liver damage or neurological impairment, according to federal health officials. Over the years, many regions have declared emergencies and issued “do not drink” advisories. Pet and animal deaths have also been reported after the animals came in contact with affected water.

Freshwater HABs can cause myriad social and economic problems for communities and are a problematic public health issue, said Lima. Testing and monitoring for certain cyanotoxins, such as microcystin, cylindrospermopsin, saxitoxin and anatoxin-a, occur because methods are available to do so, but despite the fact that guanitoxin is the second most toxic cyanotoxin, “no one’s looking for it” because the right methods aren’t available for detection and monitoring, Lima added.

As a PhD student in 2016, Lima found a set of genes she suspected was responsible for making guanitoxin by a cyanobacterium isolated from a large freshwater bloom in Brazil. The strain was isolated from the Tapacurá reservoir in Pernambuco, Brazil and has been maintained and cultivated by Marli Fiore, Lima’s former PhD advisor and co-author of the study

After this discovery, Lima looked for a partnership to confirm her suspicion. So, in 2018 she traveled to UC San Diego to work with Moore, who had established the first biochemical studies on guanitoxin back in the early 1990s. The team of scientists worked together to establish the precise functions of all nine enzymes that convert an ordinary amino acid to a neurotoxin, Lima said.

After discovering the genes involved in the production of guanitoxin and carefully validating their functions, researchers searched through thousands of samples from publically available environmental data for the guanitoxin biosynthetic genes.

The researchers were able to detect toxin genes for guanitoxin in environmental hotspots in the United States in populated areas, said Moore, who is a co-corresponding author of the study. The two areas of concern, where the toxin genes were regularly detected for guanitoxin, were in Lake Erie near Toledo, Ohio and in Lake Mendota, Wisconsin.Other areas of detection include the Amazon River in Brazil, the Columbia River in Oregon and the Delaware River in Delaware.

“We found these genes in lots of different fresh water sources, but nobody has looked for or monitored for this particular toxin environmentally,” said Shaun McKinnie, a chemistry and biochemistry assistant professor at UC Santa Cruz and former postdoctoral scholar in the Moore Lab, who contributed to the study.

“Here’s this neurotoxic potential in these lakes that people use recreationally, but this toxin has gone under the radar until our work,” Fallon said.

Moore said follow-up work should include fieldwork to detect other areas where guanitoxin may be produced.

Cyanobacterial blooms are becoming more and more prevalent in the United States and worldwide, mostly because of climate change and the introduction of fertilizers and other chemicals related to farming into bodies of water.

While HABs can be visible on the surface of freshwater bodies, the federal Environmental Protection Agency (EPA) states “cyanotoxins can be present before and after blooms are visible. Therefore, it is recommended that cyanotoxin levels be confirmed through laboratory testing of the water.”

“Now that we figured out the guanitoxin pathway at the genomic level, we can also give additional pieces of information to say: ‘This is a safe body of water, or this is a less safe body of water; Does this have the ability to become toxic and can we predict toxic events?'” McKinnie said.

The researchers have filed a provisional patent application based on the concept of using the guanitoxin biosynthetic gene sequences they identified in the lab and applying molecular diagnostics using those sequences to find the genes in the environment.

In addition to Lima, Fallon, Moore, Fiore, and McKinnie, other study co-authors include Endrews Delbaje, Ernani Pinto and Felipe Dörr from the University of São Paulo; former Moore Lab scientist Hanna Luhavaya; current Scripps Oceanography PhD student Steffaney Wood; UC Santa Cruz researchers Jennifer Cordoza, Austin Hopiavuori, and Jackson Baumgartner; Jonathon Chekan from University of North Carolina Greensboro; Danillo Alvarenga from the University of Copenhagen; and Augusto Etchegaray from the Pontifical Catholic University of Campinas in Brazil.

The study was funded by the National Institute of Environmental Health Sciences, the Sao Paulo Research Foundation, and the National Council for Scientific and Technological Development. Other funding was from the Simons Foundation Fellowship of the Life Sciences Research Foundation; the Brazilian Federal Agency for the Support Evaluation of Graduate Education; startup funding and a Faculty Research Grant from UC Santa Cruz.