Last week, NASA's $2.7 billion Perseverance rover made a picture-perfect landing on the floor of Mars's Jezero crater, which scientists believe was filled to the brim with water 3.8 billion years ago. Two kilometers away looms the rover's primary target: a fossilized river delta, created as muddy water spilled into the crater—ideal for preserving signs of life. But before Perseverance starts the long climb up into the delta, to drill samples that will eventually be returned to Earth, it will examine the rocks beneath its six aluminum wheels. The rover landed near outcrops of rock layers that may have originally been laid down before and after the lake and the delta. The NASA team will probe them for clues to the nature and timing of the brief period when water flowed—and life might have flourished. Even the first images returned to Earth, grainy and taken from the underneath the rover, left the team elated, says Katie Stack Morgan, the mission's deputy project scientist at NASA's Jet Propulsion Laboratory (JPL). “We have enough for the scientists to really sink their teeth into.” The rover's arrival at Mars was filled with nail-biting drama, even as the precise, autonomous descent unfolded like clockwork. After the spacecraft plunged by parachute through the thin air, a rocket-propelled hovercraft took over, seeking a boulder-free spot before lowering the rover from nylon cords. The final moments, captured in breathtaking detail by cameras below the hovercraft, show the rover landing in a cloud of dust. “We did have a pretty clean run,” says Allen Chen, head of the rover's landing team at JPL, in a dry understatement. “It did what it had to do.” The touchdown marks NASA's ninth successful landing on the martian surface out of 10 tries. ![Figure] GRAPHIC: C. BICKEL/ SCIENCE After 3 days, the rover had executed 5000 commands and scientific instruments were certifying their health, says Jessica Samuels, an engineer and mission manager at JPL. “Everything is coming back exactly how we want it to.” The rover raised its camera mast 2 meters above the surface to capture a panorama of its surroundings. After several days updating software, the team plans to wiggle the rover's wheels and conduct a short test drive. The rover will also extend its five-jointed, 2-meter-long robotic arm, which carries the rover's coring drill and several more cameras, and put it through some calisthenics. A second robotic arm, designed to manipulate a cache of dust and rock samples inside the rover, will be run through its paces. Stored in 43 ultraclean tubes, those samples represent the start of a multibillion-dollar, multinational effort to collect martian rocks and return them for analysis on Earth; two follow-up missions to retrieve the samples are planned for later this decade ( Science , 22 November 2019, p. ). Within its first 2 years, the rover is expected to fill nearly half the tubes on its trek of more than 10 kilometers to the crater's rim. The rest will be filled in an extended mission, as the rover trundles beyond the crater to ancient highlands thought to have once held geothermal springs. Perseverance's primary mission is to search for evidence of past life, captured in the delta mudstones and other rocks likely to preserve organic molecules—or even fossilized life. But interpreting this evidence will also require a better understanding of Mars's climatic past, from clues that can be collected right away by the rover. The first opportunity to drill a sample could come within a few months, on the flat, pebble-strewn terrain where Perseverance landed. Some scientists believe these rocks are from an ancient lava flow that erupted long after the lake disappeared, arguing that they look the way Hawaiian flows might if bombarded by meteorites and whipped by winds for several billion years. But when Perseverance's predecessor, the Curiosity rover, explored similar rocks in Gale crater and its ancient lake, most of what scientists had thought were lava fields turned out to be sedimentary rocks: ground up volcanic bits ferried by water and deposited in layers, presumably in the vanished lake. The early pictures from Perseverance are difficult to interpret: Rocks riddled with holes could be pumice, porous from gas escaping from cooling lava, or they could be sedimentary rocks, perforated over time by water. Bigger boulders in the distance look like ancient volcanic rocks: dark and coated by a light-colored dust. Fortunately, Perseverance's scientific instruments are designed to pin down the rocks' origin. Cameras on the mast could spy distinctive angular striped layers, called cross-bedding, that only form when deposited as sediments. A camera mounted on the end of the rover's robotic arm for microscopic views could capture the grain of minerals: Sedimentary rocks, for example, are typically rounded by their watery travels. Two other instruments on the arm will fire x-rays and ultraviolet laser light at rock samples, provoking reactions that could reveal chemical fingerprints of volcanic or sedimentary rocks. It's a crucial distinction. If the rocks are volcanic—either lava deposits or, more likely, ash from a distant eruption—they'll contain trace radioactive elements that decay at a certain rate, so when samples are returned to Earth, lab scientists could date the eruption and put a bound on the age of the lake. Any date will also help pin down the highly uncertain overall martian timeline, currently dated by counting the number of craters on a given terrain. (Older surfaces are pocked with more craters.) Sampling such a volcanic rock would “provide a critical anchor to the timing of events we are looking at,” says Ken Farley, the mission's project scientist and a geologist at the California Institute of Technology. The rover's initial path is likely to cross another intriguing target just 250 meters away on the crater floor: outcrops that, from orbit, appear rich in both olivine, a volcanic mineral, and carbonates, which can form when olivine is exposed to water and carbon dioxide. If this layer is volcanic ash from an eruption that preceded the Jezero lake, radioactive dates from it and the potential volcanic layer deposited on the lakebed should bracket the lake's existence in time. Moreover, isotopes of oxygen in the carbonates could reveal the temperature of the water that formed the mineral; balmy water would suggest Mars was once warm and wet for millions of years at a time, whereas water near freezing would argue for sporadic bursts of warmth. The carbonate might even contain gas bubbles—samples of the ancient martian atmosphere, which could allow scientists to see whether it held methane or other greenhouse gases that would have warmed early Mars. “That obviously would be game changing,” says Timothy Goudge, a planetary scientist at the University of Texas, Austin, who led the team that made the case for Jezero as a landing site. There will be no drilling at the landing site itself. But there will be flying. After the monthlong commissioning phase is over, the team will find a nearby, flat spot to loose the 1.8-kilogram Ingenuity helicopter, which survived the landing attached to the rover's belly. With a fuselage the size of a tissue box, Ingenuity is a technology demonstration, a bid to fly a rotor-powered vehicle on another planet for the first time. After being dropped to the surface, the helicopter will furiously spin its rotors to ascend 3 meters in the air for 20 seconds. Four additional, higher flights could follow, over a total of 30 days, says MiMi Aung, Ingenuity's project manager at JPL. On later flights the helicopter could collect reconnaissance images for terrain off the rover's main path. “It will be truly a Wright brothers moment,” Aung says, “but on another planet.” : pending:yes : http://www.sciencemag.org/content/366/6468/932
Texas A&M University and University of Oklahoma researchers have designed a reinforcement-based algorithm that automates the prediction of underground oil and gas reserves. Texas A&M University (TAMU) and University of Oklahoma researchers have developed a reinforcement-based algorithm that automates forecasting of subterranean properties, enabling accurate prediction of oil and gas reserves. The algorithm focuses on the correct characterization of the underground environment based on rewards accumulated for making correct predictions of pressure and flow anticipated from boreholes. The TAMU team learned that within 10 iterations of reinforcement learning, the algorithm could correctly and rapidly predict the properties of simple subsurface scenarios. TAMU's Siddharth Misra said, "We have turned history matching into a sequential decision-making problem, which has the potential to reduce engineers' efforts, mitigate human bias, and remove the need of large sets of labeled training data."
This week, Americans celebrated the successful delivery of NASA's Perseverance rover to its destination on the Martian surface, marking the dawn of a new era of interplanetary exploration. However, when it comes to searching the solar system around us, the US has not always led from the front. During the Reagan administration, for example, the agency saw its budget pared down in favor of building up arms ahead of an anticipated Cold War faceoff with the Soviet Union, as we see in this excerpt from David W Brown's latest work, The Mission. Excerpted from the book THE MISSION: or: How a Disciple of Carl Sagan, an Ex-Motocross Racer, a Texas Tea Party Congressman, the World's Worst Typewriter Saleswoman, California Mountain People, and an Anonymous NASA Functionary Went to War with Mars, Survived an Insurgency at Saturn, Traded Blows with Washington, and Stole a Ride on an Alabama Moon Rocket to Send a Space Robot to Jupiter in Search of the Second Garden of Eden at the Bottom of an Alien Ocean Inside of an Ice World Called Europa (A True Story) 2021 by David W. Brown. For planetary scientists, the Jimmy Carter–Ronald Reagan years were in retrospect like the Dark Ages, and they, the monks tending in enclaves to the embers of civilization.
This week's biggest story continues to be the Perseverance rover. NASA's latest space robot has brought another Linux device to Mars, and is already sending back some impressive pictures. We'll have to wait a little longer for HD video and the first drone flight -- beware of fake videos circulating on social media -- but next week should be even better. Until then you can always catch up on WandaVision's bite-size episodes, and make sure you stick around after the credits start to roll. Blizzard's online-only convention is going on this weekend, and the opening keynotes provided plenty of info about upcoming games.
The Monitor is a weekly column devoted to everything happening in the WIRED world of culture, from movies to memes, TV to Twitter. Look, it's been a god-awful week. Winter storms have caused power outages and chaos from Oregon to Texas. Reply All cohost PJ Vogt and others stepped down following accusations of a toxic culture at Gimlet Media. Unemployment is still on the rise.
When I relocated from my predominantly Black suburb in Dallas, Texas to an immensely diverse neighborhood in Brooklyn, I didn't expect to receive so many matches on Tinder and Hinge from non-Black men. I had always found myself in mostly white spaces -- college, jobs, vacations -- yet white men never took a deep interest in me before I moved to the East Coast. And while I had spent two years dating a German guy who was studying abroad at my university, it was only by transplant that a non-Black person really showed interest in courting me beyond a "you're pretty for a Black girl" comment. Eventually, I stopped swiping on non-Black men altogether. There had been several cases before when a white man would match with me and then DM me something obscure like my skin tone reminding him of chocolate or feeling the need to tell me he's always wanted to fuck a Black girl.
When surgeons remove cancer, one of the first questions is, "Did they get it all?" Researchers from Rice University and the University of Texas MD Anderson Cancer Center have created a new microscope that can quickly and inexpensively image large tissue sections, potentially during surgery, to find the answer. The microscope can rapidly image relatively thick pieces of tissue with cellular resolution, and could allow surgeons to inspect the margins of tumors within minutes of their removal. It was created by engineers and applied physicists at Rice and is described in a study published in the Proceedings of the National Academy of Sciences. "The main goal of the surgery is to remove all the cancer cells, but the only way to know if you got everything is to look at the tumor under a microscope," said Rice's Mary Jin, a Ph.D. student in electrical and computer engineering and co-lead author of the study.
Phase separation, an idea about how cells organize their contents and functions into dropletlike compartments, has divided biologists. For 7 years as president of the Howard Hughes Medical Institute, Robert Tjian helped steer hundreds of millions of dollars to scientists probing provocative ideas that might transform biology and biomedicine. So the biochemist was intrigued a couple of years ago when his graduate student David McSwiggen uncovered data likely to fuel excitement about a process called phase separation, already one of the hottest concepts in cell biology. Phase separation advocates hold that proteins and other molecules self-organize into denser structures inside cells, like oil drops forming in water. That spontaneous sorting, proponents assert, serves as a previously unrecognized mechanism for arranging the cell's contents and mustering the molecules necessary to trigger key cellular events. McSwiggen had found hints that phase separation helps herpesviruses replicate inside infected cells, adding to claims that the process plays a role in functions as diverse as switching on genes, anchoring the cytoskeleton, and repairing damaged DNA. “It's pretty clear this process is at play throughout the cell,” says biophysicist Clifford Brangwynne of Princeton University. The pharmaceutical industry is as excited as some academic researchers, given studies linking phase separation to cancer, amyotrophic lateral sclerosis (ALS), diabetes, and other diseases. Dewpoint Therapeutics, a startup pursuing medical treatments targeting cellular droplets, recently signed development deals worth more than $400 million with pharma giants Merck and Bayer. And three other companies looking to exploit the process opened their doors late last year. Reflecting that enthusiasm, Science picked phase separation as a runner-up in its 2018 Breakthrough of the Year issue. Tjian says he was agnostic at first about the importance of the process. But after McSwiggen's findings inspired him and colleagues to look more closely at the range of claims, the researchers began to have doubts. Tjian and a camp of similarly skeptical biologists now argue that the evidence that liquidlike condensates arise naturally in cells is largely qualitative and obtained with techniques that yield equivocal results—in short, they believe much of the research is shoddy. Moreover, the contention that those intracellular droplets perform important roles “has gone from hypothetical to established dogma with no data,” says Tjian, who stepped down as president of Howard Hughes in 2016 and now co-directs a lab at the University of California (UC), Berkeley. “That to me is so perverse and destructive to the scientific discovery process.” Although proponents of phase separation bridle at some of those criticisms, many scientists agree that the research requires a jolt of rigor. “I don't think the whole field is bunk,” says biophysicist Stephanie Weber of McGill University. “But we do need to be more careful” in identifying instances of phase separation in cells and ascribing functions to them. The process may be less important than many scientists now assert, adds quantitative cell biologist Amy Gladfelter of the University of North Carolina, Chapel Hill. Some researchers, she says, have tried to make it “the answer to everything.” PHASE SEPARATION COULD ANSWER a fundamental question that has nagged biologists for more than 100 years: How do cells arrange their contents so that the molecules necessary to carry out a particular job are in the right place at the right time? One obvious way is with internal membranes, such as those fencing off the Golgi bodies and mitochondria. Yet many other well-known cellular structures, including the nucleolus—an organelle within the nucleus—and the RNA-processing Cajal bodies, lack membranes. Phase separation is an appealing answer. Many proteins sport sticky patches that attract other proteins of the same or a different type. Test tube studies have shown that under certain conditions, such as when protein concentration climbs above a certain level, the molecules may begin to huddle, forming dropletlike condensates. Researchers understand the mechanics best for proteins, but nucleic acids such as RNA could also aggregate with proteins. If the process happens in the cell, it could generate and maintain organelles and permit unique functions. “It's a principle that could explain how many things in the cell and nucleus are organized,” says biophysicist Mustafa Mir of the University of Pennsylvania, who as a postdoc once worked with Tjian. Although biologists mooted a role for intracellular droplets as far back as the 1890s, evidence that they are vital began to coalesce a little over 10 years ago. Brangwynne, then a postdoc at the Max Planck Institute of Molecular Cell Biology and Genetics, was tracing P granules, flecks of protein and RNA that, in nematode embryos, mark the cells that go on to produce sperm and eggs. To observe the granules' movements, Brangwynne squeezed worm gonads that harbor the structures between two microscope cover slips. Under pressure, P granules responded not like solids but like liquids, flowing along the surface of the nucleus and dripping off, he and colleagues reported in Science in 2009. The granules' watery behavior “was mind-blowing. It was so different than anything in cells,” says Weber, a former postdoc of Brangwynne's. In 2012, Brangwynne and colleagues saw similar fluid features in the nucleolus, a dense mix of proteins, RNA, and DNA that manufactures ribosomes, the cell's protein factories. The same year, biophysicist Michael Rosen of the University of Texas Southwestern Medical Center and colleagues showed that three proteins that collaborate to organize part of the cytoskeleton form liquid droplets in a test tube solution. They found that the process speeds the assembly of one type of skeletal fiber in vitro—and might do the same in the cell. Scientists have since reported dozens of examples of cellular structures that are round, prone to fuse, and tend to bead on or flow across surfaces—hallmarks of droplets formed by phase separation (see graphic, p. 338). To confirm that a molecular gathering in a cell is a liquid and not something more solid, scientists often deploy a technique called fluorescence recovery after photobleaching (FRAP). Using a cell that contains fluorescent proteins, researchers zap the region in question with a laser to darken the molecules and then trace how long the fluorescence takes to diffuse back in from other parts of the cell. A liquid, which the fluorescent proteins easily penetrate, should light up more quickly than a solid. Another test involves applying 1,6-hexanediol, a compound that fractures some of the molecular interactions that hold droplets together, to determine whether the structure dissolves. Rosen notes that three papers published last year in Cell offer some of the strongest evidence for phase separation in cells. One, from Brangwynne's lab, showed a particular protein had to reach a threshold concentration in cells to allow formation of stress granules—organelles that pop up during hard times and have been attributed to phase separation. The other two studies also identified threshold conditions for phase separation. Because a threshold is an attribute of the process, the studies provide “good but not perfect data that these structures are going through phase separation,” Rosen says. Many researchers are now convinced that phase separation explains many aspects of cell organization and function. Several research groups have reported that the mechanism helps convene the hundreds of proteins that carry out transcription, the process of reading DNA to produce the RNA instructions for making proteins. Similar molecular corralling may underlie functions including memory in fruit flies, immune cells' responses to pathogens, DNA silencing, transmission of nerve impulses across synapses, and reproduction of SARS-CoV-2, the pandemic coronavirus. Conversely, phase separation may cause disease when it goes awry. In 2018, for example, biophysicist Tanja Mittag of St. Jude Children's Research Hospital and colleagues revealed that mutations that promote several kinds of tumors disrupt the ability of the protein SPOP, which helps eliminate proteins that spur growth of cancer cells, to form droplets in test tube solutions. The researchers proposed that phase separation is key to SPOP's cleanup function in cells, and thwarting it allows cancer-promoting proteins to accumulate. Faulty phase separation could also spur damage by aiding the formation of the toxic intracellular inclusions, or protein globs, that amass in neurodegenerative illnesses such as ALS, Alzheimer's disease, and Parkinson's disease. For example, in some ALS patients the protein FUS is mutated and forms inclusions in their neurons. In the test tube, the mutated protein condenses into droplets that then morph into furry knots of fibers resembling the inclusions. In 2018, biochemist Dorothee Dormann of the Ludwig Maximilian University of Munich and colleagues discovered a possible reason: The mutated version of FUS shrugs off a protein bodyguard that prevents the normal variety from undergoing phase separation and clumping in the test tube. YET THAT SATISFYING PICTURE may be growing murky as more researchers have raised doubts about phase separation. In 2019, for instance, scientists organized a debate at Wiston House, a posh 16th century manor south of London, in part to mull whether the process helped control gene activity. About 30 participants hashed over the evidence that the process occurs in cells with the help of “free-flowing champagne,” recalls Mir, one of the presenters. The group's conclusion, he says, was that the support for many putative cases of phase separation in cells is shaky. Tjian, who was not at the meeting, came around to a similar conclusion because of new data from McSwiggen. McSwiggen's early evidence showed that in herpesvirus-infected cells, the replication compartments—clusters of protein and DNA that help produce new copies of the pathogen—are round and merge with each other, suggesting they result from phase separation. After tracking individual proteins within cells, though, McSwiggen and colleagues determined the molecules diffuse just as fast through the compartments as through the rest of the nucleus. In a true condensate, molecular crowding should have hindered diffusion. Other researchers found the negative evidence compelling when it was published later in 2019, soon after the Wiston House debate. The study is “a really important cautionary tale,” Weber says. The results spurred Tjian, McSwiggen, Mir, and Xavier Darzacq, a cell biologist who co-directs the UC Berkeley lab with Tjian, to scrutinize the phase separation literature. Later that year, in a December 2019 issue of Genes and Development , they published a scathing review of 33 studies that claimed to detect the process in cells. Tjian says he was “really disappointed by the quality of the papers.” The evidence, he and his co-authors wrote, was “often phenomenological and inadequate to discriminate between phase separation and other possible mechanisms.” Too often, he and the other review authors asserted, researchers looking for phase separation rely on qualitative indicators—shape, for example—rather than quantitative data. Moreover, because many intracellular structures possibly formed by phase separation are so small, they are near what's known as the diffraction limit of traditional light microscopes. As a result, the structures may look like fuzzy orbs, but their real shape isn't discernible. Tjian and colleagues also chastised researchers for often assuming the protein concentration in a cell is high enough to trigger phase separation, instead of actually measuring it. Overinterpretation “is rampant” in this type of research, Tjian says. The scientists questioned the FRAP measurements that underpin many claims of phase separation. In the hands of different scientists, the group noted, FRAP recovery rates for the same molecule can range from less than 1 second to several minutes, indicating the technique is too variable to confirm phase separation. Darzacq adds that FRAP “only shows you have a liquid. You have liquid everywhere in the cell.” Many of the congregations that researchers have identified with FRAP or other techniques are probably transient collections of molecules that only last a few seconds, Darzacq and Tjian say. ![Figure] Dropping inCREDITS: (GRAPHIC) V. ALTOUNIAN/ SCIENCE ; (IMAGE) C. BRANGWYNNE ET AL., SCIENCE , 324, 5935, 1729 (2020) The review was “an invitation for all of us to proceed with a more careful and thoughtful in-depth analysis of cellular condensates,” says molecular biophysicist Sua Myong of Johns Hopkins University. Although some scientists have been meticulous, “it has not been true of the field,” Rosen adds. Brangwynne says he, too, sees value in the critique. “I agree that we need quantitative approaches.” For example, he concurs that researchers need to be more rigorous when interpreting imaging results so that “every diffraction-limited blob” isn't declared an example of phase separation. Other recent papers have also raised doubts about cases of phase separation. In 2019 in Non-Coding RNA , Weber and a co-author weighed the support for phase separation in the cell nucleus and concluded that solid data back its role in forming three structures, including the nucleolus, but not two other structures commonly attributed to the process. And in April 2020 in Molecular Cell , biophysicist Fabian Erdel of the Center for Integrative Biology in Toulouse, France, and colleagues published a new investigation of heterochromatin—silenced regions of the genome in which DNA coils tightly with various proteins. Previous work suggested phase separation of the intracellular protein HP1 helped stretches of heterochromatin bunch up. But Erdel's team discovered that HP1 didn't form stable liquid droplets in mouse cells and that the size of the densely packed DNA regions didn't depend on the amount of the protein. Brangwynne and other researchers argue that even if some individual findings cited by Tjian and colleagues remain in dispute, the field is making progress toward more solid results. To provide some of the rigor of test tube studies, he and his team have developed a technique for seeding cells with what they call corelets, combinations of molecular fragments that cluster when exposed to light. The corelets trigger droplet formation in cells, allowing the researchers to more precisely probe what protein concentrations are necessary for phase separation and which parts of the molecule are required for the behavior. Even Tjian and colleagues give the approach high marks. Mir, who has been skeptical of much of the evidence for phase separation, agrees that the field seems to be moving away from the “everything is phase separation” stage to a more nuanced discussion of the formation and functions of condensates. “It's like any supertrendy thing in science. The noise subsides, and you are left with the truth.” To get to that truth, however, researchers “desperately need” new tools and a better understanding of the basic rules for how condensates form in cells, Gladfelter says. Scientists also need patience, she says, noting the field “tried to grow up and answer everything really fast.” But she's confident researchers will eventually sort out the real importance of phase separation in cells. “Give us time. We'll get there.” : pending:yes
Tesla has given the first look at its new tabless battery cell, dubbed 4680, and Roadrunner production line that, according to CEO Elon Musk, 'will make full-size cars in the same way to cars are made.' The tabless battery was first unveiled in September during the firm's Battery Day, but was only shown by Musk via a PowerPoint presentation. Now, the time has come for Musk to show the world what Tesla has been working on at its pilot battery factory in Fremont, Texas. The one-minute clip shows the white and blue battery moving through different assembly stages with the help of armed and wheeled robots. Tesla also used this opportunity to announce it is taking applications for manufacturing jobs at its planned battery facilities in Berlin and Texas.
What do IT leaders believe the future of the profession will be, and what kind of threats will be most pervasive down the line? Dallas, TX-based cloud security firm Trend Micro recently carried out new research which reveals that over two-fifths (41%) of IT leaders believe that AI will replace their role by 2030. Its predictions report, Turning the Tide, forecasts that remote and cloud-based systems will be ruthlessly targeted in 2021. The research was compiled from interviews with 500 IT directors and managers, CIOs and CTOs and does not look good for their career prospects. Only 9% of respondents were confident that AI would definitely not replace their job within the next decade.