Aurelia Butler

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    in Heart

    Sharks face rising odds of extinction even as other big fish populations recover

    After decades of population declines, the future is looking brighter for several tuna and billfish species, such as southern bluefin tuna, black marlins and swordfish, thanks to years of successful fisheries management and conservation actions. But some sharks that live in these fishes’ open water habitats are still in trouble, new research suggests.

    These sharks, including oceanic whitetips and porbeagles, are often caught by accident within tuna and billfish fisheries. And a lack of dedicated management of these species has meant their chances of extinction continue to rise, researchers report in the Nov. 11 Science. 

    The analysis evaluates the extinction risk of 18 species of large ocean fish over nearly seven decades. It provides “a view of the open ocean that we have not had before,” says Colin Simpfendorfer, a marine biologist at James Cook University in Australia who was not involved in this research.

    “Most of this information was available for individual species, but the synthesis for all of the species provides a much broader picture of what is happening in this important ecosystem,” he says.

    In recent years, major global biodiversity assessments have documented declines in species and ecosystems across the globe, says Maria José Juan-Jordá, a fisheries ecologist at the Spanish Institute of Oceanography in Madrid. But these patterns are poorly understood in the oceans.

    To fill this gap, Juan-Jordá and her colleagues looked to the International Union for Conservation of Nature’s Red List, which evaluates changes in a species’s extinction risk. The Red List Index evaluates the risk of extinction of an entire group of species. The team specifically targeted tunas, billfishes and sharks — large predatory fishes that have influential roles in their open ocean ecosystems. 

    Red List Index assessments occur every four to 10 years. In the new study, the researchers built on the Red List criteria to develop a way of tracking extinction risk continuously over time, rather than just within the IUCN intervals.

    Juan-Jordá and her colleagues did this by compiling data on species’ average age at reproductive maturity, changes in population biomass and abundance from fish stock assessments for seven tuna species, like the vulnerable bigeye and endangered southern bluefin; six billfish species, like black marlin and sailfish; and five shark species. The team combined the data to calculate extinction risk trends for these 18 species from 1950 to 2019.

    The team found that the extinction risk for tunas and billfishes increased throughout the last half of the 20th century, with the trend reversing for tunas starting in the 1990s and billfishes in the 2010s. These shifts are tied to known reductions in fishing deaths for these species that occurred at the same time.

    The results are positive for tunas and billfishes, Simpfendorfer says. But three of the seven tunas and three of the six billfishes that the researchers looked at are still considered near threatened, vulnerable or endangered. “Now is not the time for complacency in managing these species,” Simpfendorfer says.

    But shark species are floundering in these very same waters where tuna and billfish are fished, where the sharks are often caught as bycatch. 

    Many open ocean sharks — like the silky shark (Carcharhinus falciformis) (pictured) — continue to decline, often accidentally caught by fishers seeking other large fish.Fabio Forget

    “While we are increasingly sustainably managing the commercially important, valuable target species of tunas and billfishes,” says Juan-Jordá, “shark populations continue to decline, therefore, the risk of extinction has continued to increase.”

    Some solutions going forward, says Juan-Jordá, include catch limits for some species and establishing sustainability goals within tuna and billfish fisheries beyond just the targeted species, addressing the issue of sharks that are incidentally caught. And it’s important to see if measures taken to reduce shark bycatch deaths are actually effective, she says. 

    “There is a clear need for significant improvement in shark-focused management, and organizations responsible for their management need to act quickly before it is too late,” Simpfendorfer says.  More

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    in Computers Math

    Mimicking life: Breakthrough in non-living materials

    Researchers at the Eelkema Lab have discovered a new process that uses fuel to control non-living materials, similar to what living cells do. The reaction cycle can easily be applied to a wide range of materials and its rate can be controlled — a breakthrough in the emerging field of such reactions. The discovery is a step towards soft robotics; soft machines that can sense what is happening in their environment and respond accordingly. The chemists published their findings in Nature Communications last month.
    Chemist Rienk Eelkema and his group try to mimic nature, specifically the chemical reactions in living cells that provide the fuel to control the cell. The toolbox of reactions that drive non-living materials in the same way is limited, Eelkema explains. “Up to now, there are only about five types of reactions that are widely used by researchers. Those reactions have two major drawbacks: their rate is difficult to control and they only work on a specific set of molecules.” Eelkema and PhD candidate Benjamin Klemm, lead author of the publication, found a new type of reaction whose rate can be effectively controlled and which also works on a wide range of materials.
    Swelling gel
    “The essence of the reaction cycle is that it can switch between an uncharged and a charged particle by adding a chemical fuel to it,” Eelkema explains. “This allows us to charge materials and thus modify the structures of those materials, because equal charges repel each other and different charges attract each other. The type and amount of fuel determines the reaction rate, and therefore how long a charge and thus a given structure exists.” The researchers used their reaction cycle to charge a hydrogel, for example, after which the charges repelled each other and the gel began to swell.
    Soft robots
    The cycle of chemical reactions could be useful for building soft robots: little devices that are physically soft, like our skin and tissues, and can perform specific functions. “Soft robots do already exist, for example microparticles controlled externally through magnetic or electric fields. But ultimately you’d want a robot to be able to control itself: to see for itself where it is and what is happening and then respond accordingly,” says Eelkema. “You can program our cycle into a particle in advance, then leave it alone, and it performs its function independently as soon as it encounters a signal to do so.”
    Eelkema’s next step is to link the process to the environment by adding signal processing to it: “For example, a polymer particle could contain some components of such a cycle. When it encounters the last part of the reaction, the cycle is completed, serving as a signal to disintegrate or swell up, for example.”
    The definition of life
    Cells of humans or other organisms need energy for a variety of functions: to move, to sense that something is happening or to divide. “This is also the reason why we humans need to eat,” Eelkema explains. “That linking of energy to function takes place through chemical reactions and is what defines living beings. It enables cells to control when and where structures are formed or processes take place, locally and for a limited time.”
    In contrast, non-living materials can exist forever and function without an energy supply. Until a decade ago, there were no processes that could use a chemical fuel to drive interactions in non-living materials. Eelkema: “We introduced that here in Delft, along with a few other places, and since then the field has exploded.”
    Story Source:
    Materials provided by Delft University of Technology. Note: Content may be edited for style and length. More

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    in Computers Math

    En route to human-environment interaction technology with soft microfingers

    Humans have always been fascinated by scales different than theirs, from giant objects such as stars, planets and galaxies, to the world of the tiny: insects, bacteria, viruses and other microscopic objects. While the microscope allows us to view and observe the microscopic world, it is still difficult to interact with it directly.
    However, human-robot interaction technology might change all that. Microrobots, for instance, can interact with the environment at much smaller scales than us. Microsensors have been used for measuring forces exerted by insects during activities such as flight or walking. However, most studies so far have only focused on measuring insect behavior rather than a direct insect-microsensor interaction.
    Against this backdrop, researchers from Ritsumeikan University in Japan have now developed a soft micro-robotic finger that can enable a more direct interaction with the microworld. The study, led by Professor Satoshi Konishi, was published in Scientific Reports on 10 October 2022 “A tactile microfinger is achieved by using a liquid metal flexible strain sensor. A soft pneumatic balloon actuator acts as an artificial muscle, allowing control and finger-like movement of the sensor. With a robotic glove, a human user can directly control the microfingers. This kind of system allows for a safe interaction with insects and other microscopic objects,” explains Prof. Konishi.
    Using their newly developed microrobot setup, the research team investigated the reaction force of a pill bug as a representative sample of an insect. The pill bug was fixed in place using a suction tool and the microfinger was used to apply a force and measure the reaction force of the bug’s legs.
    The reaction force measured from the legs of the pill bug was approximately 10 mN (millinewtons), which agreed with previously estimated values. While a representative study and a proof-of-concept, this result shows great promise towards realizing direct human interactions with the microworld. Moreover, it can have applications even in augmented reality (AR) technology. Using robotized gloves and micro-sensing tools such as the microfinger, many AR technologies concerning human-environment interactions on the microscale can be realized.
    “With our strain-sensing microfinger, we were able to directly measure the pushing motion and force of the legs and torso of a pill bug — something that has been impossible to achieve previously! We anticipate that our results will lead to further technological development for microfinger-insect interactions, leading to human-environment interactions at much smaller scales,” remarks Prof. Konishi.
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    Materials provided by Ritsumeikan University. Note: Content may be edited for style and length. More

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    in Computers Math

    Growing pure nanotubes is a stretch, but possible

    Like a giraffe stretching for leaves on a tall tree, making carbon nanotubes reach for food as they grow may lead to a long-sought breakthrough.
    Materials theorists Boris Yakobson and Ksenia Bets at Rice University’s George R. Brown School of Engineering show how putting constraints on growing nanotubes could facilitate a “holy grail” of growing batches with a single desired chirality.
    Their paper in Science Advances describes a strategy by which constraining the carbon feedstock in a furnace would help control the “kite” growth of nanotubes. In this method, the nanotube begins to form at the metal catalyst on a substrate, but lifts the catalyst as it grows, resembling a kite on a string.
    Carbon nanotube walls are basically graphene, its hexagonal lattice of atoms rolled into a tube. Chirality refers to how the hexagons are angled within the lattice, between 0 and 30 degrees. That determines whether the nanotubes are metallic or semiconductors. The ability to grow long nanotubes in a single chirality could, for instance, enable the manufacture of highly conductive nanotube fibers or semiconductor channels of transistors.
    Normally, nanotubes grow in random fashion with single and multiple walls and various chiralities. That’s fine for some applications, but many need “purified” batches that require centrifugation or other costly strategies to separate the nanotubes.
    The researchers suggested hot carbon feedstock gas fed through moving nozzles could effectively lead nanotubes to grow for as long as the catalyst remains active. Because tubes with different chiralities grow at different speeds, they could then be separated by length, and slower-growing types could be completely eliminated. More

  • 163 Shares149 Views

    in Computers Math

    Robots are taking over jobs, but not at the rate you might think

    It’s easy to believe that robots are stealing jobs from human workers and drastically disrupting the labor market; after all, you’ve likely heard that chatbots make more efficient customer service representatives and that computer programs are tracking and moving packages without the use of human hands.
    But there’s no need to panic about a pending robot takeover just yet, says a new study from BYU sociology professor Eric Dahlin. Dahlin’s research found that robots aren’t replacing humans at the rate most people think, but people are prone to severely exaggerate the rate of robot takeover.
    The study, recently published in Socius: Sociological Research for a Dynamic World, found that only 14% of workers say they’ve seen their job replaced by a robot. But those who have experienced job displacement due to a robot overstate the effect of robots taking jobs from humans by about three times.
    To understand the relationship between job loss and robots, Dahlin surveyed nearly 2,000 individuals about their perceptions of jobs being replaced by robots. Respondents were first asked to estimate the percentage of employees whose employers have replaced jobs with robots. They were then asked whether their employer had ever replaced their job with a robot.
    Those who had been replaced by a robot (about 14%), estimated that 47% of all jobs have been taken over by robots. Similarly, those who hadn’t experienced job replacement still estimated that 29% of jobs have been supplanted by robots.
    “Overall, our perceptions of robots taking over is greatly exaggerated,” said Dahlin. “Those who hadn’t lost jobs overestimated by about double, and those who had lost jobs overestimated by about three times.”
    Attention-grabbing headlines predicting a dire future of employment have likely overblown the threat of robots taking over jobs, said Dahlin, who noted that humans’ fear of being replaced by automated work processes dates to the early 1800s.
    “We expect novel technologies to be adopted without considering all of the relevant contextual impediments such as cultural, economic, and government arrangements that support the manufacturing, sale, and use of the technology,” he said. “But just because a technology can be used for something does not mean that it will be implemented.”
    Dahlin says these findings are consistent with previous studies, which suggest that robots aren’t displacing workers. Rather, workplaces are integrating both employees and robots in ways that generate more value for human labor.
    “An everyday example is an autonomous, self-propelled machine roaming the isles and cleaning floors at your local grocery store,” says Dahlin. “This robot cleans the floors while employees clean under shelves or other difficult-to-reach places.”
    Dahlin says the aviation industry is another good example of robots and humans working together. Airplane manufacturers used robots to paint airplane wings. A robot can administer one coat of paint in 24 minutes — something that would take a human painter hours to accomplish. Humans load and unload the paint while the robot does the painting.
    Story Source:
    Materials provided by Brigham Young University. Original written by Tyler Stahle. Note: Content may be edited for style and length. More

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    in Computers Math

    Silicon nanochip could treat traumatic muscle loss

    Technology developed by researchers at the Indiana University School of Medicine that can change skin tissue into blood vessels and nerve cells has also shown promise as a treatment for traumatic muscle loss.
    Tissue nanotransfection is a minimally invasive nanochip device that can reprogram tissue function by applying a harmless electric spark to deliver specific genes in a fraction of a second.
    A new study, published in Nature Partner Journals Regenerative Medicine, tested tissue nanotransfection-based gene therapy as a treatment, with the goal of delivering a gene known to be a major driver of muscle repair and regeneration. They found that muscle function improved when tissue nanotransfection was used as a therapy for seven days following volumetric muscle loss in rats. It is the first study to report that tissue nanotransfection technology can be used to generate muscle tissue and demonstrates its benefit in addressing volumetric muscle loss.
    Volumetric muscle loss is the traumatic or surgical loss of skeletal muscle that results in compromised muscle strength and mobility. Incapable of regenerating the amount of lost tissue, the affected muscle undergoes substantial loss of function, thus compromising quality of life. A 20 percent loss in mass can result in an up to 90 percent loss in muscle function.
    Current clinical treatments for volumetric muscle loss are physical therapy or autologous tissue transfer (using a person’s own tissue), the outcomes of which are promising but call for improved treatment regimens.
    “We are encouraged that tissue nanotransfection is emerging as a versatile platform technology for gene delivery, gene editing and in vivo tissue reprogramming,” said Chandan Sen, director of the Indiana Center for Regenerative Medicine and Engineering, associate vice president for research and Distinguished Professor at the IU School of Medicine. “This work proves the potential of tissue nanotransfection in muscle tissue, opening up a new avenue of investigational pursuit that should help in addressing traumatic muscle loss. Importantly, it demonstrates the versatility of the tissue nanotransfection technology platform in regenerative medicine.”
    Sen also leads the regenerative medicine and engineering scientific pillar of the IU Precision Health Initiative and is lead author on the new publication.
    The Indiana Center for Regenerative Medicine and Engineering is home to the tissue nanotransfection technology for in vivo tissue reprogramming, gene delivery and gene editing. So far, tissue nanotransfection has also been achieved in blood vessel and nerve tissue. In addition, recent work has shown that topical tissue nanotransfection can achieve cell-specific gene editing of skin wound tissue to improve wound closure.
    Other study authors include Andrew Clark, Subhadip Ghatak, Poornachander Reddy Guda, Mohamed S. El Masry and Yi Xuan, all of IU, and Amy Y. Sato and Teresita Bellido of Purdue University.
    This work was supported by Department of Defense Discovery Award W81XWH-20-1-251. It is also supported in part by NIH grant DK128845 and Lilly Endowment INCITE (Indiana Collaborative Initiative for Talent Enrichment).
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    Materials provided by Indiana University. Note: Content may be edited for style and length. More

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    in Computers Math

    Magnetism or no magnetism? The influence of substrates on electronic interactions

    A new study at Monash University illustrates how substrates affect strong electronic interactions in two-dimensional metal-organic frameworks.
    Materials with strong electronic interactions can have applications in energy-efficient electronics. When these materials are placed on a substrate, their electronic properties are changed by charge transfer, strain, and hybridisation.
    The study also shows that electric fields and applied strain could be used to ‘switch’ interacting phases such as magnetism on and off, allowing potential applications in future energy-efficient electronics.
    TURNING MAGNETISM ON AND OFF WITH SUBSTRATES
    Strong interactions between electrons in materials gives rise to effects such as magnetism and superconductivity. These effects have uses in magnetic memory, spintronics, and quantum computing, making them appealing for emerging technologies.
    Last year, another study at Monash discovered strong electronic interactions in a 2D metal-organic framework. The researchers found signatures of magnetism in this material. They showed that this magnetism arose due to strong interactions that were only present when the non-magnetic components were brought together. More

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    in Heart

    Greenland’s frozen hinterlands are bleeding worse than we thought

    Sea level rise may proceed faster than expected in the coming decades, as a gargantuan flow of ice slithering out of Greenland’s remote interior both picks up speed and shrinks.

    By the end of the century, the ice stream’s deterioration could contribute to nearly 16 millimeters of global sea level rise — more than six times the amount scientists had previously estimated, researchers report November 9 in Nature.

    The finding suggests that inland portions of large ice flows elsewhere could also be withering and accelerating due to human-caused climate change, and that past research has probably underestimated the rates at which the ice will contribute to sea level rise (SN: 3/10/22).

    “It’s not something that we expected,” says Shfaqat Abbas Khan, a glaciologist at the Technical University of Denmark in Kongens Lyngby. “Greenland and Antarctica’s contributions to sea level rise in the next 80 years will be significantly larger than we have predicted until now.”

    In the new study, Khan and colleagues focused on the Northeast Greenland Ice Stream, a titanic conveyor belt of solid ice that crawls about 600 kilometers out of the landmass’s hinterland and into the sea. It drains about 12 percent of the country’s entire ice sheet and contains enough water to raise global sea level more than a meter. Near the coast, the ice stream splits into two glaciers, Nioghalvfjerdsfjord and Zachariae Isstrøm.

    While frozen, these glaciers keep the ice behind them from rushing into the sea, much like dams hold back water in a river (SN: 6/17/21). When the ice shelf of Zachariae Isstrøm collapsed about a decade ago, scientists found that the flow of ice behind the glacier started accelerating. But whether those changes penetrated deep into Greenland’s interior remained largely unresolved.

    “We’ve mostly concerned ourselves with the margins,” says atmosphere-cryosphere scientist Jenny Turton of the nonprofit Arctic Frontiers in Tromsø, Norway, who was not involved in the new study. That’s where the most dramatic changes with the greatest impacts on sea level rise have been observed, she says (SN: 4/30/22, SN: 5/16/13).

    Keen to measure small rates of movement in the ice stream far inland, Khan and his colleagues used GPS, which in the past has exposed the tortuous creeping of tectonic plates (SN: 1/13/21). The team analyzed GPS data from three stations along the ice stream’s main trunk, all located between 90 and 190 kilometers inland.

    The data showed that the ice stream had accelerated at all three points from 2016 to 2019. In that time frame, the ice speed at the station farthest inland increased from about 344 meters per year to surpassing 351 meters per year.

    The researchers then compared the GPS measurements with data collected by polar-orbiting satellites and aircraft surveys. The aerial data agreed with the GPS analysis, revealing that the ice stream was accelerating as far as 200 kilometers upstream. What’s more, shrinking — or thinning — of the ice stream that started in 2011 at Zachariae Isstrøm had propagated more than 250 kilometers upstream by 2021. 

    “This is showing that glaciers are responding along their length faster than we had thought previously,” says Leigh Stearns, a glaciologist from the University of Kansas in Lawrence, who was not involved in the study.

    Khan and his colleagues then used the data to tune computer simulations that forecast the ice stream’s impact on sea level rise. The researchers predict that by 2100, the ice stream will have singlehandedly contributed between about 14 to 16 millimeters of global sea level rise — as much as Greenland’s entire ice sheet has in the last 50 years.

    The findings suggest that past research has probably underestimated rates of sea level rise due to the ice stream, Stearns and Turton say. Similarly, upstream thinning and acceleration in other large ice flows, such as those associated with Antarctica’s shrinking Pine Island and Thwaites glaciers, might also cause sea levels to rise faster than expected, Turton says (SN: 6/9/22, SN: 12/13/21).

    Khan and his colleagues plan to investigate inland sections of other large ice flows in Greenland and Antarctica, with the hopes of improving forecasts of sea level rise (SN: 1/7/20).

    Such forecasts are crucial for adapting to climate change, Stearns says. “They’re helping us better understand the processes so that we can inform the people who need to know that information.” More