The report, published in Science Advances, features new calculations for what researchers refer to as a water expulsion mechanism. This occurs when the solid bedrock the West Antarctic Ice Sheet sits on rebounds upward as the ice melts and the total weight of the ice sheet decreases. The bedrock sits below sea level so when it lifts, it pushes water from the surrounding area into the ocean, adding to global sea level rise.

The new predictions show that in the case of a total collapse of the ice sheet, global sea level rise estimates would be amplified by an additional meter within 1,000 years.

“The magnitude of the effect shocked us,” said Linda Pan, a Ph.D. in earth and planetary science in GSAS who co-led the study with fellow graduate student Evelyn Powell. “Previous studies that had considered the mechanism dismissed it as inconsequential.”

“If the West Antarctic Ice Sheet collapsed, the most widely cited estimate of the resulting global mean sea level rise that would result is 3.2 meters,” said Powell. “What we’ve shown is that the water expulsion mechanism will add an additional meter, or 30 percent, to the total.”

But this is not just a story about impact that will be felt in hundreds of years. One of the simulations Pan and Powell performed indicated that by the end of this century global sea level rise caused by melting of the West Antarctic Ice Sheet would increase 20 percent by the water expulsion mechanism.

“Every published projection of sea level rise due to melting of the West Antarctic ice sheet that has been based on climate modeling, whether the projection extends to the end of this century or longer into the future, is going to have to be revised upward because of their work,” said Jerry X. Mitrovica, the Frank B. Baird Jr. Professor of Science in the Department of Earth and Planetary Sciences and a senior author on the paper. “Every single one.”

Pan and Powell, both researchers in Mitrovica’s lab, started this research while working on another sea level change project but switched to this one when they noticed more water expulsion from the West Antarctic ice sheet than they were expecting.

The researchers wanted to investigate how the expulsion mechanism affected sea level change when the low viscosity, or the easy flowing material of the Earth’s mantle beneath West Antarctica, is considered. When they incorporated this low viscosity into their calculations they realized water expulsion occurred much faster than previous models had predicted.

“No matter what scenario we used for the collapse of the West Antarctic Ice Sheet, we always found that this extra one meter of global sea level rise took place,” Pan said.

The researchers hope their calculations show that, in order to accurately estimate global sea level rise associated with melting ice sheets, scientists need to incorporate both the water expulsion effect and the mantle’s low viscosity beneath Antarctica.

“Sea level rise doesn’t stop when the ice stops melting,” Pan said. “The damage we are doing to our coastlines will continue for centuries.”

Story Source:

Materials provided by Harvard University. Original written by Juan Siliezar. Note: Content may be edited for style and length.

Research from Lancaster University Management School and Texas Tech University, published in European Economic Review looked into the relationship between the location choices of potentially polluting firms and levels of local income to discover if firms made strategic decisions on site locations based on population demographics.

The team studied potentially polluting firms across Texas, and found a correlation between lower income locations and the probability of potentially polluting firms choosing to locate there. Their data, from the US Environment Agency’s Toxic Release Inventory also showed the relative frequency of toxic releases decreased as household income rose.

“We looked both at whether firms made decisions on their location based on demographics — particularly income — of the local areas, and also whether firms made different choices on limiting the possibilities of toxic release through waste management based on those same statistics,” said co-author Professor Dakshina De Silva, of Lancaster University’s Department of Economics.

“Firms reduced their releases and increased spending on waste management in higher income areas — evidenced by a greater number of waste management services — while lower income areas were disproportionately subject to toxic releases.

“The patterns we observed lead us to conclude that, at least partially, potentially polluting firms seek to maximise their expected profits and recognise the financial risk associated with a release in different areas.”

Releasing toxic chemicals in the environment is costly for firms because they will have to implement clean-up programmes, pay penalties and compensate local residents for damages. Higher incomes — and associated property values — increase the costs as damages are linked to reduced property values and lost income due to limitations on working.

“Potentially polluting firms seeking to maximise profits will be concerned with the liability of toxic releases and the threat such releases pose to their financial results,” said co-author Dr Anita Schiller, of Lancaster University. “They will therefore take into account the demographics of an area when valuing the legal costs and compensation they would have to pay out in the event of a toxic release, and balance this with the cost of reducing the likelihood of such a release.

“In areas where there is a higher income and higher property prices, compensation levels will go up in the event of an incident, with the possibility of collective action by residents and businesses also increasing. Potentially polluting firms must also consider the financial risk of a release and the costs of managing such an incident’s likelihood.”

The researchers found that levels of toxic release had declined steadily since 2000 — by 34% between 2000 and 2006 and by a further 21% since 2006 — but suggested this drop was not uniform, with potentially polluting firms reducing releases through waste management where local opposition to their presence was the highest.

Co-author Dr Aurelie Slechten added: “Combined with our finding that economic activity and local income are linked with spending on waste management and with levels of toxic releases, this implies that the group most affected by releases will be poorer populations in industrial areas.

“Without further action, the disparity in exposure to toxic releases faced by certain groups will not be reduced by simply requiring that firms report their releases. Serious thought needs to be given to regulation on compensation schemes.”

Story Source:

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

Researchers named the vulnerability Spectre because the flaw was built into modern computer processors that get their speed from a technique called “speculative execution,” in which the processor predicts instructions it might end up executing and preps by following the predicted path to pull the instructions from memory. A Spectre attack tricks the processor into executing instructions along the wrong path. Even though the processor recovers and correctly completes its task, hackers can access confidential data while the processor is heading the wrong way.

Since Spectre was discovered, the world’s most talented computer scientists from industry and academia have worked on software patches and hardware defenses, confident they’ve been able to protect the most vulnerable points in the speculative execution process without slowing down computing speeds too much.

They will have to go back to the drawing board.

A team of University of Virginia School of Engineering computer science researchers has uncovered a line of attack that breaks all Spectre defenses, meaning that billions of computers and other devices across the globe are just as vulnerable today as they were when Spectre was first announced. The team reported its discovery to international chip makers in April and will present the new challenge at a worldwide computing architecture conference in June.

The researchers, led by Ashish Venkat, William Wulf Career Enhancement Assistant Professor of Computer Science at UVA Engineering, found a whole new way for hackers to exploit something called a “micro-op cache,” which speeds up computing by storing simple commands and allowing the processor to fetch them quickly and early in the speculative execution process. Micro-op caches have been built into Intel computers manufactured since 2011.

Venkat’s team discovered that hackers can steal data when a processor fetches commands from the micro-op cache.

“Think about a hypothetical airport security scenario where TSA lets you in without checking your boarding pass because (1) it is fast and efficient, and (2) you will be checked for your boarding pass at the gate anyway,” Venkat said. “A computer processor does something similar. It predicts that the check will pass and could let instructions into the pipeline. Ultimately, if the prediction is incorrect, it will throw those instructions out of the pipeline, but this might be too late because those instructions could leave side-effects while waiting in the pipeline that an attacker could later exploit to infer secrets such as a password.”

Because all current Spectre defenses protect the processor in a later stage of speculative execution, they are useless in the face of Venkat’s team’s new attacks. Two variants of the attacks the team discovered can steal speculatively accessed information from Intel and AMD processors.

“Intel’s suggested defense against Spectre, which is called LFENCE, places sensitive code in a waiting area until the security checks are executed, and only then is the sensitive code allowed to execute,” Venkat said. “But it turns out the walls of this waiting area have ears, which our attack exploits. We show how an attacker can smuggle secrets through the micro-op cache by using it as a covert channel.”

Venkat’s team includes three of his computer science graduate students, Ph.D. student Xida Ren, Ph.D. student Logan Moody and master’s degree recipient Matthew Jordan. The UVA team collaborated with Dean Tullsen, professor of the Department of Computer Science and Engineering at the University of California, San Diego, and his Ph.D. student Mohammadkazem Taram to reverse-engineer certain undocumented features in Intel and AMD processors.

They have detailed the findings in their paper: “I See Dead ?ops: Leaking Secrets via Intel/AMD Micro-Op Caches.”

This newly discovered vulnerability will be much harder to fix.

“In the case of the previous Spectre attacks, developers have come up with a relatively easy way to prevent any sort of attack without a major performance penalty” for computing, Moody said. “The difference with this attack is you take a much greater performance penalty than those previous attacks.”

“Patches that disable the micro-op cache or halt speculative execution on legacy hardware would effectively roll back critical performance innovations in most modern Intel and AMD processors, and this just isn’t feasible,” Ren, the lead student author, said.

“It is really unclear how to solve this problem in a way that offers high performance to legacy hardware, but we have to make it work,” Venkat said. “Securing the micro-op cache is an interesting line of research and one that we are considering.”

Venkat’s team has disclosed the vulnerability to the product security teams at Intel and AMD. Ren and Moody gave a tech talk at Intel Labs worldwide April 27 to discuss the impact and potential fixes. Venkat expects computer scientists in academia and industry to work quickly together, as they did with Spectre, to find solutions.

The team’s paper has been accepted by the highly competitive International Symposium on Computer Architecture, or ISCA. The annual ISCA conference is the leading forum for new ideas and research results in computer architecture and will be held virtually in June.

Venkat is also working in close collaboration with the Processor Architecture Team at Intel Labs on other microarchitectural innovations, through the National Science Foundation/Intel Partnership on Foundational Microarchitecture Research Program.

Venkat was well prepared to lead the UVA research team into this discovery. He has forged a long-running partnership with Intel that started in 2012 when he interned with the company while he was a computer science graduate student at the University of California, San Diego.

This research, like other projects Venkat leads, is funded by the National Science Foundation and Defense Advanced Research Projects Agency.

Venkat is also one of the university researchers who co-authored a paper with collaborators Mohammadkazem Taram and Tullsen from UC San Diego that introduce a more targeted microcode-based defense against Spectre. Context-sensitive fencing, as it is called, allows the processor to patch running code with speculation fences on the fly.

Introducing one of just a handful more targeted microcode-based defenses developed to stop Spectre in its tracks, “Context-Sensitive Fencing: Securing Speculative Execution via Microcode Customization” was published at the ACM International Conference on Architectural Support for Programming Languages and Operating Systems in April 2019. The paper was also selected as a top pick among all computer architecture, computer security, and VLSI design conference papers published in the six-year period between 2014 and 2019.

The new Spectre variants Venkat’s team discovered even break the context-sensitive fencing mechanism outlined in Venkat’s award-winning paper. But in this type of research, breaking your own defense is just another big win. Each security improvement allows researchers to dig even deeper into the hardware and uncover more flaws, which is exactly what Venkat’s research group did.

To that end, the Rice lab of materials scientist Ming Tang, in collaboration with physicist Fei Zhou at Lawrence Livermore National Laboratory, introduced a technique to predict the evolution of microstructures — structural features between 10 nanometers and 100 microns — in materials.

Their open-access paper in the Cell Press journal Patterns shows how neural networks (computer models that mimic the brain’s neurons) can train themselves to predict how a structure will grow under a certain environment, much like a snowflake forms from moisture in nature.

In fact, snowflake-like, dendritic crystal structures were one of the examples the lab used in its proof-of-concept study.

“In modern material science, it’s widely accepted that the microstructure often plays a critical role in controlling a material’s properties,” Tang said. “You not only want to control how the atoms are arranged on lattices, but also what the microstructure looks like, to give you good performance and even new functionality.

“The holy grail of designing materials is to be able to predict how a microstructure will change under given conditions, whether we heat it up or apply stress or some other type of stimulation,” he said.

Tang has worked to refine microstructure prediction for his entire career, but said the traditional equation-based approach faces significant challenges to allow scientists to keep up with the demand for new materials.

“The tremendous progress in machine learning encouraged Fei at Lawrence Livermore and us to see if we could apply it to materials,” he said.

Fortunately, there was plenty of data from the traditional method to help train the team’s neural networks, which view the early evolution of microstructures to predict the next step, and the next one, and so on.

“This is what machinery is good at, seeing the correlation in a very complex way that the human mind is not able to,” Tang said. “We take advantage of that.”

The researchers tested their neural networks on four distinct types of microstructure: plane-wave propagation, grain growth, spinodal decomposition and dendritic crystal growth.

In each test, the networks were fed between 1,000 and 2,000 sets of 20 successive images illustrating a material’s microstructure evolution as predicted by the equations. After learning the evolution rules from these data, the network was then given from 1 to 10 images to predict the next 50 to 200 frames, and usually did so in seconds.

The new technique’s advantages quickly became clear: The neural networks, powered by graphic processors, sped the computations up to 718 times for grain growth, compared to the previous algorithm. When run on a standard central processor, they were still up to 87 times faster than the old method. The prediction of other types of microstructure evolution showed similar, though not as dramatic, speed increases.

Comparisons with images from the traditional simulation method proved the predictions were largely on the mark, Tang said. “Based on that, we see how we can update the parameters to make the prediction more and more accurate,” he said. “Then we can use these predictions to help design materials we have not seen before.

“Another benefit is that it’s able to make predictions even when we do not know everything about the material properties in a system,” Tang said. “We couldn’t do that with the equation-based method, which needs to know all the parameter values in the equations to perform simulations.”

Tang said the computation efficiency of neural networks could accelerate the development of novel materials. He expects that will be helpful in his lab’s ongoing design of more efficient batteries. “We’re thinking about novel three-dimensional structures that will help charge and discharge batteries much faster than what we have now,” Tang said. “This is an optimization problem that is perfect for our new approach.”

The research team found the host sponges and their guest worms in a remote area in Darwin, Australia, where these animals live. They collected samples, some of which are now located in the collections of the Biodiversity Museum at the University of Göttingen. For their analysis, they combined techniques such as histology, electronic optical microscopy, immunohistochemistry, confocal laser microscopy, and X-ray computed microtomography. This made it possible to obtain three-dimensional images both of the worms’ different internal organs and of the interior of the sponges that they inhabit. The scientists show that when the body of these animals divides, so do all their internal organs, something that has never been observed before.

Furthermore, the three-dimensional models developed during this research have made it possible to find a new anatomical structure exclusive to these animals, which is formed by muscular bridges that cross between the different organs whenever their body has to form a new branch. These muscular bridges are essential because they confirm that the bifurcation process does not occur in the early stages of life, but once the worms are adults and then throughout their lives. In addition, researchers propose that this unique “fingerprint” of muscle bridges makes it theoretically possible to distinguish the original branch from the new one in each bifurcation of the complex body network.

In addition, this new study investigates the anatomy of the reproductive units (stolons) that develop in the posterior ends of the body when these animals are about to reproduce, and that are characteristic of the family to which they belong (Syllidae). The results show that these stolons form a new brain and have their own eyes. This allows them to navigate their environment when they are detached from the body for fertilization. This brain is connected to the rest of the nervous system by a ring of nerves that surrounds the intestine.

“Our research solves some of the puzzles that these curious animals have posed ever since the first branched annelid was discovered at the end of the 19th century,” explains senior author Dr Maite Aguado, University of Göttingen. “However, there is still a long way to go to fully understand how these fascinating animals live in the wild. For example, this study has concluded that the intestine of these animals could be functional, yet no trace of food has ever been seen inside them and so it is still a mystery how they can feed their huge branched bodies. Other questions raised in this study are how blood circulation and nerve impulses are affected by the branches of the body.” This research lays the foundations for understanding how these creatures live and how their incredible branched body came to evolve.

Story Source:

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

Bacteria contain enzymes called LanC that are capable of producing small proteins called lanthipeptides, which are characterized by the addition of a thiol group to a modified serine or threonine amino acid. Similar proteins — called LanC-like or LanCL — have been found in different eukaryotic cells for decades, but their function was unknown.

“LanCLs are found in nearly all higher organisms, including humans. Although scientists have worked on these proteins for over 20 years, we didn’t know their function. We had several hypotheses, which we kept ruling out based on our experiments,” said Wilfred van der Donk (MMG), a professor of chemistry and investigator of the Howard Hughes Medical Institute.

The first breakthrough came in 2015, when the Nair lab in the Department of Biochemistry solved the crystal structure of a LanC-containing protein in bacteria. The protein was bound to another enzyme called a kinase, which modifies proteins by adding a phosphate group. Inspired by this discovery, the researchers tested whether LanCL proteins were also binding to kinases in eukaryotic cells. “We saw that they were able to bind to many kinases, including AKT and mTOR, and all of a sudden the pieces of the puzzle started forming a picture,” van der Donk said.

The next piece fell into place in collaboration with Benjamin Davis, a professor of chemistry at the University of Oxford. The Davis group showed that eliminating a particular phosphate group in kinases causes them to become activated. Scientists had assumed that such processed proteins would be inactive. Together, the Illinois and Oxford groups were able to show that LanCL adds glutathione to kinases with eliminated phosphate groups, after which the kinases became deactivated. “We realized that when the LanCL proteins are absent, the cell has a big problem because there are active proteins floating around that need to be turned off,” van der Donk said.

The importance of these proteins became evident in mice that lacked them. “A third of the mice that lack these enzymes die when they are between four to six months old. They die suddenly without getting sick and we still don’t understand why,” said Jie Chen (GNDP), a professor of cell and developmental biology.

The researchers are interested in understanding the role of these proteins and making a complete list of all the possible targets of LanCLs. “When you have abnormal kinases, it can cause all kinds of problems, including cancer. LanCL proteins eliminate these damaged kinases and it is possible that they also affect other proteins that we are not aware of. We need to connect their cellular functions to the results we saw in the mice,” Chen said.

“This study is just the tip of the iceberg. Since these proteins are found everywhere, you can also imagine their effects in feedstock and the future of farming,” said Satish Nair (MME/MMG), Head of the Department of Biochemistry.

“This study was possible because of the persistence of our graduate students. Most of us would have given up long ago because the studies were initially going nowhere,” Nair said. “It also shows the importance of exploratory research, where you’re essentially just looking around. Although it is risky, it is great to see that there are rewards for students who stick it out,” van der Donk said.