Tagged: NOVA Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 2:46 pm on October 17, 2014 Permalink | Reply
    Tags: , , NOVA   

    From NOVA: “Insulin-Producing Stem Cells Could Provide Lasting Diabetes Treatments” 

    PBS NOVA

    NOVA

    Fri, 17 Oct 2014
    Sarah Schwartz

    Researchers have crafted what may be a powerful weapon in the fight against diabetes: A new line of insulin-producing cells that has been shown to reverse diabetes in mice within forty days. Scientists hope that these cells may someday do the same in humans.

    The new cells, called “Stage 7” or “S7” for their seven-step production process, are the product of a study by researchers at the University of British Columbia and the pharmaceutical company Janssen. S7 cells are made to mimic human beta cells, which are damaged or destroyed in patients with diabetes. Healthy beta cells produce insulin and help regulate blood sugar; S7 cells are grown from human embryonic stem cells and are programmed to do the same.

    cells
    A microscopic view of beta cells derived from stem cells

    “The advance that they have made is that they’ve got better cells in the test tube, cells that have more insulin and can secrete insulin in response to glucose,” said Dr. Gordon Weir, a physician and researcher at Joslin Diabetes Center and Harvard Medical School. “People haven’t been able to do that before.”

    Human embryonic stem cells, like those used to produce the S7 line, show great promise for producing beta cell replacements. Just last week, another team of researchers led by Dr. Douglas Melton at Harvard University announced their own line of insulin-producing cells, also produced from human embryonic stem cells. Like S7 cells, the Harvard team’s cells produce insulin in response to high blood sugar and can reverse diabetes symptoms in mice.

    The hope is that cells like these could be injected into diabetic patients, restoring normal beta cell function. Timothy Kieffer, head of the diabetes research group at University of British Columbia and a co-author of the S7 cell study, said that treatment with these cells could be curative, though other researchers caution that additional work has to be done before that’s the case.

    Cellular transplantation has already been shown to effectively combat diabetes. Since the late 1980s, beta cells extracted from cadaver pancreases have been used to normalize blood sugar in diabetics. But these treatments are not an option for many patients. In addition to the challenges of establishing a treatment program, Weir said, “there aren’t enough pancreatic donors to even scratch the surface.” These transplanted cells also tend to stop working over time, said Dr. David Nathan, the director of the Diabetes Center and Clinical Research Center at Massachusetts General Hospital. Whole organ pancreatic transplants usually last longer and have been increasingly successful in recent years, Nathan says. But both organ and cell transplants from cadavers require immunosuppressive treatments, which can cause tumors, skin cancers, and weakened immune systems.

    Beta cells grown from stem cells could solve some of these problems. It is possible that stem cells could be developed to reduce or eliminate the need for immunosuppression, Nathan said. Plus, their supply is theoretically unlimited. “If you can make them in a test tube, in a dish, whatever—well, that gets rid of the problem of donor pancreases,” Nathan said. While S7 cells are most efficient when made from human embryonic stem cells, they can also be made using induced pluripotent stem cells, which are reprogrammed adult cells. This, Weir noted, could eliminate “ethical issues” involved with embryonic stem cell use.

    Kieffer believes that a stem cell-based treatment would also be superior to insulin supplementation, the current standard of treatment for type 1 diabetes. In type 1 diabetes, which Kieffer’s research targets, beta cells are destroyed by an autoimmune attack, and patients require external insulin to survive. Even with advanced treatment options like insulin pumps, Weir said, it is challenging to keep blood sugar in a normal range. “And if you push hard enough to drive the blood sugar down, you end up getting into trouble with insulin reactions,” Weir said. “The blood sugar goes too low and that’s dangerous.”

    But S7 cells have some challenges to overcome before they can replace current treatments. For one, it can be difficult to control the development of stem cells, Nathan pointed out. Kieffer agreed that more research is needed to mature the cells, which are still not identical to human beta cells because they react more slowly to sugar and don’t release as much insulin. Kieffer’s collaborators are also working to scale up production of the S7 line. Meanwhile, the Harvard study uses a protocol that already seems to allow relatively large-scale development of insulin-producing cells.

    There are also other challenges to treating type 1 diabetes with cells like S7 because of the autoimmune nature of the disease. If beta cell transplants are injected into type 1 diabetics, Weir said, “those cells are still going to be subject to the immune problem that killed the cells in the first place.” Kieffer said that the “next hurdle” for his team is to see if S7 cells will work inside devices that prevent immune attack.

    These “immunobarrier” devices are essentially capsules that contain implanted stem cells, allowing the exchange of nutrients and insulin while blocking attacking immune cells. Nathan and Weir expressed reservations about these devices. Nathan wondered if they can be designed to allow sufficient blood flow and nutrients to all the cells inside, while Weir questioned whether there could be a device large enough to hold the number of cells needed to control the disease. Still, in August, the company Viacyte started clinical trials with such a device, using a line of cells less developed than S7. “We’ll have to wait and see,” Weir said.

    Because of the autoimmunity problem inherent in type 1 diabetes, Weir says that it may be easier to use beta cell transplantations to treat type 2 diabetes instead. Up to 95% of diabetic patients have this form of the disease, which involves no autoimmunity. Instead, in type 2, beta cells “wear out” such that the body stops responding to insulin.

    “You can take a type 2 diabetic and give them insulin injections and normalize the sugar if you do it carefully,” Weir said. “So, a beta cell transplant is just the same thing as giving an insulin injection.” He feels the effects of such treatment could be profound. “You can put cells in and normalize the blood sugar for years,” he said. “So if you want to call that a cure, I’d go along with that.” Nathan disagrees: because type 2 diabetics have some pancreatic function, it can be simpler and easier to treat their symptoms. Because of this, he believes that cellular transplantations will mostly be useful to combat type 1 diabetes.

    Nathan doesn’t think that beta cell transplantations are an “appropriate clinical option”—yet. “The balance between risk and benefit isn’t quite right,” he says. Still, he hopes that someday, a cellular treatment will be advanced enough to safely and effectively treat this disease. “To cure type 1 diabetes would be a godsend,” he says. “To actually do a single procedure that essentially takes away the disease at low risk would be great.”

    Though several questions must be answered before they start curing patients, S7 cells are a promising step in the fight against a disease that affects 347 million people worldwide. The field is moving quickly towards its goal; as Kieffer writes, “I am very optimistic that we are narrowing down on a cure for diabetes.”

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 11:15 am on October 15, 2014 Permalink | Reply
    Tags: , , Loop Quantum Gravity, NOVA, Quantum Gravity, , , White Holes   

    From NOVA: “Are White Holes Real?” 

    PBS NOVA

    NOVA

    Tue, 19 Aug 2014
    Maggie McKee

    Sailors have their krakens and their sea serpents. Physicists have white holes: cosmic creatures that straddle the line between tall tale and reality. Yet to be seen in the wild, white holes may be only mathematical monsters. But new research suggests that, if a speculative theory called loop quantum gravity is right, white holes could be real—and we might have already observed them.

    wh

    A white whole is, roughly speaking, the opposite of a black hole. “A black hole is a place where you can go in but you can never escape; a white hole is a place where you can leave but you can never go back,” says Caltech physicist Sean Carroll. “Otherwise, [both share] exactly the same mathematics, exactly the same geometry.” That boils down to a few essential features: a singularity, where mass is squeezed into a point of infinite density, and an event horizon, the invisible “point of no return” first described mathematically by the German physicist Karl Schwarzschild in 1916. For a black hole, the event horizon represents a one-way entrance; for a white hole, it’s exit-only.

    There is excellent evidence that black holes really exist, and astrophysicists have a robust understanding of what it takes to make one. To imagine how a white hole might form, though, we have to go out on a bit of an astronomical limb. One possibility involves a spinning black hole. According to [Albert] Einstein’s general theory of relativity, the rotation smears the singularity into a ring, making it possible in theory to travel through the swirling black hole without being crushed. General relativity’s equations suggest that someone falling into such a black hole could fall through a tunnel in space-time called a wormhole and emerge from a white hole that spits its contents into a different region of space or period of time.

    Though mathematical solutions to those equations exist for white holes, “they’re not realistic,” says Andrew Hamilton, an astrophysicist at the University of Colorado at Boulder. That is because they describe universes that contain only black holes, white holes and wormholes—no matter, radiation or energy. Indeed, previous research, including Hamilton’s, suggests that anything that falls into a spinning black hole will essentially plug up the wormhole, preventing the formation of a passage to a white hole.

    But there’s a light at the end of the wormhole, so to speak. General relativity, from which Hamilton draws his predictions, breaks down at a black hole’s singularity. “The energy density and the curvature become so large that classical gravity is not a good description of what’s happening there,” says Stephen Hsu, a physicist at Michigan State University in East Lansing. Perhaps a more complete model of gravity—one that works as well on the quantum scale as it does on large ones—would negate the instability and allow for white holes, he says.

    Indeed, a unified theory that merges gravity and quantum mechanics is one of the holy grails of contemporary physics. Applying one such theory, loop quantum gravity, to black holes, theorists Hal Haggard and Carlo Rovelli of Aix-Marseille University in France have shown that black holes could metamorphose into white holes via a quantum process. In July, they published their work online.

    Loop quantum gravity proposes that space-time is made up of fundamental building blocks shaped like loops. According to Haggard and Rovelli, the loops’ finite size prevents a dying star from collapsing all the way down into a point of infinite density, and the shrinking object rebounds into a white hole instead. This process may take just a few thousandths of a second, but thanks to the intense gravity involved, the effects of relativity make the transformation appear to take much, much longer to anyone watching from afar. That means that minuscule black holes born in the infant universe could “now be ready to pop off like firecrackers,” forming white holes, according to a report in Nature. Some of the explosions astronomers thought were supernovae may actually be the wails of newborn white holes.

    The black-to-white conversion could resolve a nettlesome conundrum known as the black hole information paradox. The notion that information can be destroyed is anathema in physics, and general relativity says that anything, including information, that falls into a black hole can never escape. These two statements are not at odds if black holes simply act as locked safes for any information they slurp up, but Stephen Hawking showed 40 years ago that black holes actually evaporate over time. That led to the disturbing possibility that the information contained within them could be lost too, triggering a debate that rages to this day.

    But if a black hole instead turns into a white hole, then “all the information is recovered,” says Haggard. “We are quite excited about this mechanism because it avoids so many of the thorny issues that surround this discussion.”

    The new work is preliminary, however, and it is far from clear whether loop quantum gravity is an accurate description of reality. The only glimpse we get of white holes might turn out to be those we model in labs and kitchen sinks. But Carroll says that’s okay. Just thinking about these possibly mythical cosmic creatures can improve physicists’ intuition, “even if the real world is messy and not like those exact situations,” he says. “That’s the way in which white holes are very useful.”

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 2:55 pm on October 3, 2014 Permalink | Reply
    Tags: , , , , , NOVA   

    From NOVA: “4 Multiverses You Might Be Living In” 

    PBS NOVA

    NOVA

    Published on Oct 3, 2014

    Could parallel universes exist? If so, what would they look like and how would they form?

    Watch, enjoy, learn.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 3:12 pm on September 27, 2014 Permalink | Reply
    Tags: , , , , NOVA   

    From NOVA: “It May Have Icy Clouds, But It’s Not a Planet, Not a Star, and Not in Our Solar System” 

    PBS NOVA

    NOVA

    Fri, 26 Sep 2014
    Joshua Sokol

    Brown dwarf W0855 was already special. A few times the size of Jupiter and super-cold, it’s halfway between a star and free-floating planet. Now ice clouds have been tentatively found in its atmosphere—which would mark the first time they’ve ever been seen on an extrasolar world.

    The solar system’s fourth-nearest companion doesn’t make it easy. It’s so faint that “I wanted to put on Rocky, do a Braveheart speech to the telescope operators,” said study author Jacqueline Faherty, who used the Las Campanas Observatory. in Chile [no hint of what telescope was used here]. She is the first astronomer to observe W0855 from the ground since it was found in data from NASA’s space-going Wide-Field Infrared Explorer (WISE) in April.

    Carnegie Las Campanas Observatory
    Las Campanas Observatory

    NASA Wise Telescope
    NASA/Wise

    w
    W0855, seen here in an artist’s conception, is a cold brown dwarf thought to have icy clouds in its soup of gases.

    Faherty’s work, which will be published in the Astrophysical Journal Letters, measured W0855’s brightness in different color bands. When compared with simulations of likely brown dwarf atmospheres, these data suggest W0855 boasts clouds of water ice and sulfide.

    On Earth, high-altitude cirrus clouds offer a point of comparison. Unlike cumulus clouds, which can contain both water vapor droplets and ice, cirrus clouds are composed of just ice crystals. Brown dwarf atmospheres are so cold and low-pressure that clouds there would form in much the same way, said astronomer Caroline Morley, whose published models were used by Faherty.

    Yet Morley and other astronomers unaffiliated with the study warn that this discovery is preliminary. “This tentative detection is made just with a few [brightness] points,” Morley wrote in an email. And Edward Wright, who studied W0855 with WISE, is skeptical that drawing conclusions from Morley’s models is the right idea. “The clouds depend on interpreting models which aren’t necessarily very good,” he said.

    It’s not that the presence of ice clouds would be shocking—just that they might not have been found yet. Kevin Luhman, who first discovered W0855, is also unconvinced. He wrote via email that, “there’s another set of cloudless models that she did not consider, and they actually agree well with her data.”

    According to these objectors, Faherty’s assumptions aren’t unreasonable. But her results depend on the brown dwarf having the same chemical blend as the Sun and on it being in chemical equilibrium—dependencies her paper also acknowledges.

    Regarding the cloud-free alternatives Luhman mentions, said Faherty, no “valid” models currently exist for comparison. Not only is the physics behind those other models unpublished, but the modelers themselves have lost confidence in their work, she said.

    All agree that NASA’s forthcoming James Webb Space Telescope will settle the question. The Webb’s coveted infrared sensitivity will let astronomers measure W0855’s whole spectrum, not just a few colors.

    For now, at least, Faherty is grateful even to find W0855 at new wavelengths and push the discussion forward. “It’s so faint that it’s at the limits, at the very hairy edge of what you can do from the ground,” she said. Her struggles with half-star, half-planet W0855 tease an even harder next step: understanding the atmospheres of planets orbiting faraway stars.

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 10:11 pm on September 25, 2014 Permalink | Reply
    Tags: , , , NOVA   

    From NOVA: “Genetically Engineering Almost Anything” 

    PBS NOVA

    NOVA

    Thu, 17 Jul 2014
    Tim De Chant and Eleanor Nelsen

    When it comes to genetic engineering, we’re amateurs. Sure, we’ve known about DNA’s structure for more than 60 years, we first sequenced every A, T, C, and G in our bodies more than a decade ago, and we’re becoming increasingly adept at modifying the genes of a growing number of organisms.

    But compared with what’s coming next, all that will seem like child’s play. A new technology just announced today has the potential to wipe out diseases, turn back evolutionary clocks, and reengineer entire ecosystems, for better or worse. Because of how deeply this could affect us all, the scientists behind it want to start a discussion now, before all the pieces come together over the next few months or years. This is a scientific discovery being played out in real time.

    dna repair
    Scientists have figured out how to use a cell’s DNA repair mechanisms to spread traits throughout a population.

    Today, researchers aren’t just dropping in new genes, they’re deftly adding, subtracting, and rewriting them using a series of tools that have become ever more versatile and easier to use. In the last few years, our ability to edit genomes has improved at a shockingly rapid clip. So rapid, in fact, that one of the easiest and most popular tools, known as CRISPR-Cas9, is just two years old. Researchers once spent months, even years, attempting to rewrite an organism’s DNA. Now they spend days.

    Soon, though, scientists will begin combining gene editing with gene drives, so-called selfish genes that appear more frequently in offspring than normal genes, which have about a 50-50 chance of being passed on. With gene drives—so named because they drive a gene through a population—researchers just have to slip a new gene into a drive system and let nature take care of the rest. Subsequent generations of whatever species we choose to modify—frogs, weeds, mosquitoes—will have more and more individuals with that gene until, eventually, it’s everywhere.

    Cas9-based gene drives could be one of the most powerful technologies ever discovered by humankind. “This is one of the most exciting confluences of different theoretical approaches in science I’ve ever seen,” says Arthur Caplan, a bioethicist at New York University. “It merges population genetics, genetic engineering, molecular genetics, into an unbelievably powerful tool.”

    We’re not there yet, but we’re extraordinarily close. “Essentially, we have done all of the pieces, sometimes in the same relevant species.” says Kevin Esvelt, a postdoc at Harvard University and the wunderkind behind the new technology. “It’s just no one has put it all together.”

    It’s only a matter of time, though. The field is progressing rapidly. “We could easily have laboratory tests within the next few months and then field tests not long after that,” says George Church, a professor at Harvard University and Esvelt’s advisor. “That’s if everybody thinks it’s a good idea.”

    It’s likely not everyone will think this is a good idea. “There are clearly people who will object,” Caplan says. “I think the technique will be incredibly controversial.” Which is why Esvelt, Church, and their collaborators are publishing papers now, before the different parts of the puzzle have been assembled into a working whole.

    “If we’re going to talk about it at all in advance, rather than in the past tense,” Church says, “now is the time.”

    “Deleterious Genes”

    The first organism Esvelt wants to modify is the malaria-carrying mosquito Anopheles gambiae. While his approach is novel, the idea of controlling mosquito populations through genetic modification has actually been around since the late 1970s. Then, Edward F. Knipling, an entomologist with the U.S. Department of Agriculture, published a substantial handbook with a chapter titled Use of Insects for Their Own Destruction. One technique, he wrote, would be to modify certain individuals to carry “deleterious genes” that could be passed on generation after generation until they pervaded the entire population. It was an idea before its time. Knipling was on the right track, but he and his contemporaries lacked the tools to see it through.

    The concept surfaced a few more times before being picked up by Austin Burt, an evolutionary biologist and population geneticist at Imperial College London. It was the late 1990s, and Burt was busy with his yeast cells, studying their so-called homing endonucleases, enzymes that facilitate the copying of genes that code for themselves. Self-perpetuating genes, if you will. “Through those studies, gradually, I became more and more familiar with endonucleases, and I came across the idea that you might be able to change them to recognize new sequences,” Burt recalls.

    Other scientists were investigating endonucleases, too, but not in the way Burt was. “The people who were thinking along those lines, molecular biologists, were thinking about using these things for gene therapy,” Burt says. “My background in population biology led me to think about how they could be used to control populations that were particularly harmful.”
    “There’s a lot to be done still, but on the scale of years, not months or decades.”

    In 2003, Burt penned an influential article that set the course for an entire field: We should be using homing endonucleases, a type of gene drive, to modify malaria-carrying mosquitoes, he said, not ourselves. Burt saw two ways of going about it—one, modify a mosquito’s genome to make it less hospitable to malaria, and two, skew the sex ratio of mosquito populations so there are no females for the males to reproduce with. In the following years, Burt and his collaborators tested both in the lab and with computer models before they settled on sex ratio distortion. (Making mosquitoes less hospitable to malaria would likely be a stopgap measure at best; the Plasmodium protozoans could evolve to cope with the genetic changes, just like they have evolved resistance to drugs.)

    Burt has spent the last 11 years refining various endonucleases, playing with different scenarios of inheritance, and surveying people in malaria-infested regions. Now, he finally feels like he is closing in on his ultimate goal.“There’s a lot to be done still,” he says. “But on the scale of years, not months or decades.”

    Cheating Natural Selection

    Cas9-based gene drives could compress that timeline even further. One half of the equation—gene drives—are the literal driving force behind proposed population-scale genetic engineering projects. They essentially let us exploit evolution to force a desired gene into every individual of a species. “To anthropomorphize horribly, the goal of a gene is to spread itself as much as possible,” Esvelt says. “And in order to do that, it wants to cheat inheritance as thoroughly as it can.” Gene drives are that cheat.

    Without gene drives, traits in genetically-engineered organisms released into the wild are vulnerable to dilution through natural selection. For organisms that have two parents and two sets of chromosomes (which includes humans, many plants, and most animals), traits typically have only a 50-50 chance of being inherited, give or take a few percent. Genes inserted by humans face those odds when it comes time to being passed on. But when it comes to survival in the wild, a genetically modified organism’s odds are often less than 50-50. Engineered traits may be beneficial to humans, but ultimately they tend to be detrimental to the organism without human assistance. Even some of the most painstakingly engineered transgenes will be gradually but inexorably eroded by natural selection.

    Some naturally occurring genes, though, have over millions of years learned how to cheat the system, inflating their odds of being inherited. Burt’s “selfish” endonucleases are one example. They take advantage of the cell’s own repair machinery to ensure that they show up on both chromosomes in a pair, giving them better than 50-50 odds when it comes time to reproduce.

    gene drive
    A gene drive (blue) always ends up in all offspring, even if only one parent has it. That means that, given enough generations, it will eventually spread through the entire population.

    Here’s how it generally works. The term “gene drive” is fairly generic, describing a number of different systems, but one example involves genes that code for an endonuclease—an enzyme which acts like a pair of molecular scissors—sitting in the middle of a longer sequence of DNA that the endonculease is programmed to recognize. If one chromosome in a pair contains a gene drive but the other doesn’t, the endonuclease cuts the second chromosome’s DNA where the endonuclease code appears in the first.

    The broken strands of DNA trigger the cell’s repair mechanisms. In certain species and circumstances, the cell unwittingly uses the first chromosome as a template to repair the second. The repair machinery, seeing the loose ends that bookend the gene drive sequence, thinks the middle part—the code for the endonuclease—is missing and copies it onto the broken chromosome. Now both chromosomes have the complete gene drive. The next time the cell divides, splitting its chromosomes between the two new cells, both new cells will end up with a copy of the gene drive, too. If the entire process works properly, the gene drive’s odds of inheritance aren’t 50%, but 100%.

    gene drive
    Here, a mosquito with a gene drive (blue) mates with a mosquito without one (grey). In the offspring, one chromosome will have the drive. The endonuclease then slices into the drive-free DNA. When the strand gets repaired, the cell’s machinery uses the drive chromosome as a template, unwittingly copying the drive into the break.

    Most natural gene drives are picky about where on a strand of DNA they’ll cut, so they need to be modified if they’re to be useful for genetic engineering. For the last few years, geneticists have tried using genome-editing tools to build custom gene drives, but the process was laborious and expensive. With the discovery of CRISPR-Cas9 as a genome editing tool in 2012, though, that barrier evaporated. CRISPR is an ancient bacterial immune system which identifies the DNA of invading viruses and sends in an endonuclease, like Cas9, to chew it up. Researchers quickly realized that Cas9 could easily be reprogrammed to recognize nearly any sequence of DNA. All that’s needed is the right RNA sequence—easily ordered and shipped overnight—which Cas9 uses to search a strand of DNA for where to cut. This flexibility, Esvelt says, “lets us target, and therefore edit, pretty much anything we want.” And quickly.

    Gene drives and Cas9 are each powerful on their own, but together they could significantly change biology. CRISRP-Cas9 allows researchers to edit genomes with unprecedented speed, and gene drives allow engineered genes to cheat the system, even if the altered gene weakens the organism. Simply by being coupled to a gene drive, an engineered gene can race throughout a population before it is weeded out. “Eventually, natural selection will win,” Esvelt says, but “gene drives just let us get ahead of the game.”
    Beyond Mosquitoes

    If there’s anywhere we could use a jump start, it’s in the fight against malaria. Each year, the disease kills over 200,000 people and sickens over 200 million more, most of whom are in Africa. The best new drugs we have to fight it are losing ground; the Plasmodium parasite is evolving resistance too quickly. And we’re nowhere close to releasing an effective vaccine. The direct costs of treating the disease are estimated at $12 billion, and the economies of affected countries grew 1.3% less per year, a substantial amount.

    Which is why Esvelt and Burt are both so intently focused on the disease. “If we target the mosquito, we don’t have to face resistance on the parasite itself. The idea is, we can just take out the vector and stop all transmission. It might even lead to eradication,” Esvelt says.

    Esvelt initially mulled over the idea of building Cas9-based gene drives in mosquitoes to do just that. He took the idea to to Flaminia Catteruccia, a professor who studies malaria at the Harvard School of Public Health, and the two grew increasingly certain that such a system would not only work, but work well. As their discussions progressed, though, Esvelt realized they were “missing the forest for the trees.” Controlling malaria-carrying mosquitoes was just the start. Cas9-based gene drives were the real breakthrough. “If it let’s us do this for mosquitos, what is to stop us from potentially doing it for almost anything that is sexually reproducing?” he realized.
    “What is to stop us from potentially doing it for almost anything that is sexually reproducing?”

    In theory, nothing. But in reality, the system works best on fast-reproducing species, Esvelt says. Short generation times allow the trait to spread throughout a population more quickly. Mosquitoes are a perfect test case. If everything were to work perfectly, deleterious traits could sweep through populations of malaria-carrying mosquitoes in as few as five years, wiping them off the map.

    Other noxious species could be candidates, too. Certain invasive species, like mosquitoes in Hawaii or Asian carp in the Great Lakes, could be targeted with Cas9-based gene drives to either reduce their numbers or eliminate them completely. Agricultural weeds like horseweed that have evolved resistance to glyphosate, a herbicide that is broken down quickly in the soil, could have their susceptibility to the compound reintroduced, enabling more farmers to adopt no-till practices, which help conserve topsoil. And in the more distant future, Esvelt says, weeds could even be engineered to introduce vulnerabilities to completely benign substances, eliminating the need for toxic pesticides. The possibilities seem endless.

    The Decision

    Before any of that can happen, though, Esvelt and Church are adamant that the public help decide whether the research should move forward. “What we have here is potentially a general tool for altering wild populations,” Esvelt says. “We really want to make sure that we proceed down this path—if we decide to proceed down this path—as safely and responsibly as possible.”

    To kickstart the conversation, they partnered with the MIT political scientist Kenneth Oye and others to convene a series of workshops on the technology. “I thought it might be useful to get into the room people with slightly different material interests,” Oye says, so they invited regulators, nonprofits, companies, and environmental groups. The idea, he says, was to get people to meet several times, to gain trust and before “decisions harden.” Despite the diverse viewpoints, Oye says there was surprising agreement among participants about what the important outstanding questions were.

    As the discussion enters the public sphere, tensions are certain to intensify. “I don’t care if it’s a weed or a blight, people still are going to say this is way too massive a genetic engineering project,” Caplan says. “Secondly, it’s altering things that are inherited, and that’s always been a bright line for genetic engineering.” Safety, too, will undoubtedly be a concern. As the power of a tool increases, so does its potential for catastrophe, and Cas9-based gene drives could be extraordinarily powerful.

    There’s also little in the way of precedent that we can use as a guide. Our experience with genetically modified foods would seem to be a good place to start, but they are relatively niche organisms that are heavily dependent on water and fertilizer. It’s pretty easy to keep them contained to a field. Not so with wild organisms; their potential to spread isn’t as limited.
    There’s little in the way of precedent that we can use as a guide.

    Aware of this, Esvelt and his colleagues are proposing a number of safeguards, including reversal drives that can undo earlier engineered genes. “We need to really make sure those work if we’re proposing to build a drive that is intended to modify a wild population,” Esvelt says.

    There are still other possible hurdles to surmount—lab-grown mosquitoes may not interbreed with wild ones, for example—but given how close this technology is to prime time, Caplan suggests researchers hew to a few initial ethical guidelines. One, use species that are detrimental to human health and don’t appear to fill a unique niche in the wild. (Malaria-carrying mosquitoes seem fit that description.) Two, do as much work as possible using computer models. And three, researchers should continue to be transparent about their progress, as they have been. “I think the whole thing is hugely exciting,” Caplan says. “But the time to really get cracking on the legal/ethical infrastructure for this technology is right now.”

    Church agrees, though he’s also optimistic about the potential for Cas9-based gene drives. “I think we need to be cautious with all new technologies, especially all new technologies that are messing with nature in some way or another. But there’s also a risk of doing nothing,” Church says. “We have a population of 7 billion people. You have to deal with the environmental consequences of that.”

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 12:39 pm on September 25, 2014 Permalink | Reply
    Tags: Identity Theft, Internet Security, NOVA   

    From NOVA: “My Identity Was Stolen. Here’s How They Did It” 

    PBS NOVA

    NOVA

    Wed, 20 Nov 2013
    Phil McKenna

    I recently received a call that I’d hoped would never come. My bank informed me that a thief with knowledge of my social security number, address, birthdate, and mother’s maiden name had succeeded in changing the contact information associated with my credit card. The representative I spoke with told me we were dealing with a professional identity thief and that I should assume all of my personal information had been compromised.

    The representative continued, instructing me on what I should do immediately to try to control the damage. I tried taking notes but I was reeling. Life as I knew it, or so I told myself, would never be the same.

    man
    “A thief with knowledge of my social security number, address, birthdate, and mother’s maiden name succeeded in changing the contact information associated with my credit card,” says NOVA Next contributor Phil McKenna.

    Each year 13 million Americans, or 5% of the entire U.S. adult population, are victims of identity theft. Fraudulent transactions, including purchases made on existing credit cards, opening new lines of credit, and wiring money from victims’ bank accounts, cost financial institutions and individuals more than $20 billion each year, according to a recent study by financial analysts at Javelin Strategy & Research. But how are identities stolen, how do banks like mine detect fraudulent use, and what, if anything, can we do to protect ourselves?

    A Numbers Game

    Try to guess an individual’s social security number and you’ll quickly realize that the nine-digit code provides the apparent anonymity of roughly 1 billion different number combinations. It’s enough to keep a den of thieves guessing from here to eternity, right? Not so says Alessandro Acquisti, professor of information technology and public policy at Carnegie Mellon University.

    In 2009, Acquisti showed that, with some basic demographic information and a general understanding of how the federal government assigns social security numbers, miscreants could predict individuals’ numbers with an alarmingly high degree of accuracy.

    Combing through millions of publicly available records of deceased individuals’ social security numbers, Acquisti and his colleagues were able to reconstruct how such numbers are assigned. Given an individual’s birthdate and the state they were born in, the researchers could, in some cases, predict the first five digits of an individual’s social security number with more than 90% accuracy.
    “Thieves are not going after one identity but thousands or millions of them.”

    All of this assumes that a thief knows the date and location of your birth, facts which some of your friends may not even know. But chances are this information is hiding in plain sight. Using a webcam and commercially available image recognition software, Acquisti’s team was able to identify by name 30% of students on a North American college campus simply by taking their picture and matching it to a database of publically available images downloaded from Facebook. In many cases the Facebook accounts provided the dates and locations of students’ births. Using this information, the team could then predict the first five digits of a student’s social security numbers in four attempts with 28% accuracy.

    Guessing the remaining four digits is relatively easy. “If you assume a brute force attack where you try combinations of one thousand different social security numbers, then the probability of successfully getting the right number for certain states and years of birth can be disturbingly high,” Acquisti says. “You can start with something as anonymous as a face in a crowd and end up with very sensitive information about that person.”

    cc
    ID thieves have gone well beyond nabbing old credit cards from your trash.

    Acquisti’s research offers a proof of concept, though it’s unclear whether identity thieves actually take such a circuitous route to acquire information. Easier targets are the data centers of financial institutions and credit bureaus that aggregate consumer information.

    Last month, online security expert Brian Krebs revealed that an underground identity theft service which illegally sold Social Security numbers had obtained much of its data by conning Experian, one of the three major credit bureaus, into selling it to them. “Secured databases are a much more concentrated target,” says Cormac Herley, a security expert with Microsoft Research. “Thieves are not going after one identity but thousands or millions of them.”

    A Call From Somewhere

    Once an individual’s identity has been stolen, thieves, as I recently discovered, often target call centers. “There are three ways to rob a bank,” says Vijay Balasubramaniyan, CEO of Pindrop Security. “You can walk in with guns, you can hack into their online systems, or you can call in using a phone. Fraudsters always move to the weakest link, and the phone channel has quickly become the weakest link.”

    What makes phones weak, Balasubramaniyan says, is a fraudster’s ability to manipulate individuals on the other end. “A computer is emotionless,” he points out. “It won’t react to you differently based on what you say. But if you have a human on the other end, you can start figuring out what their weaknesses are and start using that to your benefit.”

    Balasubramaniyan gives examples of two highly successful types of thieves his company is monitoring. One begins shouting when he doesn’t get the information he wants. He claims to have been a customer for years and threatens to report the representative to his or her supervisor if he or she don’t provide the information he seeks. Another, he says, “kills with kindness,” calling representatives “Sir” or “Madam” and complementing female representatives on the sound of their voice.

    In the past, many such attempts were thwarted when the accent of a foreign fraudster gave them away. “What if I’m a Russian hacker and I’ve stolen a US credit card?” asks Daniel Cohen, a cybersecurity strategist with RSA Security LLC. “If I call a call center, they will pick up on my accent.” RSA has seen a growing trend in recent years of underground, online marketplaces that provide identity thieves with “professional callers” who mimic the identity theft victim’s gender, age and accent. “Say I’ve stolen someone’s identity from Mississippi, I could then ask for someone with a southern accent—it’s that developed,” Cohen says.

    To prevent such call center fraud, financial institutions rely on something known as knowledge based authentication or KBA. Long the gold standard for call center security, KBA is a series of questions and answers related to things like prior residences and financial information that only the consumer should know.

    Depending on how far back the questions go, however, consumers often don’t recall the correct answers. In fact, identity thieves who obtain an individual’s credit information can often answer the questions better than the victim they are impersonating.

    site
    Black market sites offer services that help thieves profit from stolen identities, including making calls to banks, stores, and more by people with native accents.

    If fraudsters gain access to an individual’s KBA information, as likely occurred in my case, the consequences can be far worse than simply having one’s credit card information or social security number compromised. “It’s pretty much the worst thing that can happen to you from a financial data perspective,” says Avivah Litan an analyst with information technology firm Gartner, Inc.

    It’s possible that the thief had obtained my KBA information through a massive breach of KBA data uncovered on September 25 by Krebs, the security expert who revealed the recent breach at Experian. He found that hackers had entered computer servers at LexisNexis, one of the largest providers of KBA information to financial institutions. Hackers placed a “tiny unauthorized program called ‘nbc.exe’ on the company’s servers,” Krebs writes, likely placed there either by exploiting a weakness in the servers’ configuration or through a malicious email. The program was designed to open an encrypted channel of communication between LexisNexis’s internal computers and botnets, private computers infected with malicious software, that were controlled over the internet by the identity thieves. It’s unclear what data the thieves gained from the breach, though they may have acquired the KBA data of millions of Americans. “They have always been compromised,” Litan says of KBA data, “but now they are massively compromised.”
    “I have half a dozen apps on my smartphone that can spoof your number.”

    To fill the void of compromised KBA data, banks have started to rely on something known as “phoneprinting,” or the ability to verify the origin of a call. Such verification is now needed because the profusion of online and mobile phone technology in recent years has made it increasingly difficult to tell where a call is really coming from. Thieves use this to add another layer of credibility to their fraud, making it seem as though a call was originated from your number even if the caller is halfway around the world.

    “I have half a dozen apps on my smartphone that can spoof your number,” Pindrop’s Balasubramaniyan tells me when at a recent conference. To prove it, he opens an app called callerID Faker. Before I know it, the caller ID on my phone tells me I have an incoming call from my own office number.

    Balasubramaniyan has these apps on his phone for a good reason—his company offers call centers a way to verify the source of a call. By analyzing different aspects of the sound quality in a call, Pindrop’s software can quickly determine whether the call originates from a cell phone in Cincinnati or from a Skype call in Siberia. “Imagine 15 seconds into a call, your bank gets an alert saying this is not Phil McKenna,” Balasubramaniyan says.

    Pindrop’s software analyzes 147 different aspect of sound quality. It then creates a database of unique “phoneprints” for calls made from different locations using different networks and phone types.
    ana
    A Pindrop analysis of calls in a string of identity theft cases revealed the top 200 numbers connected to the thief’s actual phone number (middle).

    For example, Voice Over Internet Protocol (VoIP) calls such as those made on Skype contain something known as packet loss, or small breaks in the audio signal as a result of how the digital information is transmitted across these networks. The breaks are only milliseconds long, too short to be detected by a human ear, but contain a wealth of information. “I can look at the length of the break and tell you which company—Skype, Google Voice, or magicJack—the caller is using,” Balasubramaniyan says.

    Pindrop can also identify which network a caller is using by the background noise. Prior to the digitization of phone networks, calls made on analog telecommunication systems all broadcast a slight hiss that let you know the line was live on other end. When phone companies moved to digital transmission, there was no ambient noise. To ease the transition for users, companies recreated it, calling it “comfort noise.” “Each network did it in a different way, so it allows us to identify the network by the characteristics of their comfort noise,” Balasubramaniyan says.

    The various measures Pindrop uses allows them to correctly identify the provenance of a call, including phone type, network used, and rough geographic location, with over 90% accuracy.

    The company recently exposed a fraudster in Eastern Europe who had been using stolen KBA information. Once Pindrop’s software revealed the identity thief wasn’t who he claimed to be, it was obvious he was using stolen information. “When he was asked ‘what is your mother’s maiden name,’ we could actually hear him flipping through his notes,” Balasubramaniyan says.
    What Can You Do?

    For every breach in security new technologies emerge to try to prevent fraud, technologies that in turn will likely be thwarted at some point in the future. It’s a seemingly endless arms race between financial institutions and identity thieves. Still, I can’t help feeling like the recent theft of my information was somehow my fault.

    Not that I hadn’t taken precautions. I was careful with my personal information. I shredded documents and used strong online passwords. I didn’t fall for obvious phishing scams like pleas from wealthy Nigerians seeking to transfer large sums of money. But perhaps I should have changed passwords more frequently, added additional verification measures, or shared less on social media.

    Vern Paxson, a computer security expert at the University of California, Berkeley, absolves me of any such guilt. “Not only is there is nothing you did wrong but probably nothing you could have done differently,” he says. The problem, he says, is massive breaches at data centers like the recent ones by Experian and LexisNexis. Professional identity thieves don’t have time to weed through individuals—they’d rather exploit the richest resource, the central databases.

    No system is perfectly secure, but there are relatively easy steps that financial institutions could take now that would help prevent such breaches from occurring. Simply requiring organizations to establish security policies on how they safeguard consumer information would go a long way, says David Thaw, a professor at the University of Connecticut School of Law. In a recent study of health care and financial industries, Thaw found that institutions that had such policies were four times better at preventing security breaches than those that didn’t.

    “Fraud is as old as our species.”

    Acquisti, who showed it is possible to predict social security numbers, suggests we do away with the numbers entirely. The problem, he says, is that they are used for both identification and verification. It’s the equivalent of giving out your phone number to people so they can call you and then using that same number as the pass code for your voicemail. “No sane person would do that,” he says.

    Still, Acquisti concedes that gutting social security numbers may be prohibitively expensive. “As a whole, these costs, borne by different parties from identity theft, may be less than changing to an entirely new system,” he says. And even if we did change systems, it’s unlikely that the replacement would succeed in stopping identity theft for very long. “Fraud is as old as our species,” says Bruce Schneier, a security expert at the Berkman Center for Internet and Society at Harvard University. “The crime rate will never be zero in society. The trick is to make it manageable.”

    Schneier dismisses the severity of recent data center breaches, saying similar events have occurred on a regular basis for years. The key metric, he says, is how quickly identity theft is identified and corrected after it occurs. “A few years ago it was an absolute disaster,” Schneier says, adding that if my identity had been stolen at that time, I may well have been out $50,000 and spent years restoring my credit. In my case, my credit card company thwarted my identity thieves before they made a single charge.

    I did, however, lose several days of my life trying to shore up my compromised identity. After getting off the phone with my credit card company, I alerted the three major credit bureaus of the theft and reviewed my credit report to rule out any further damage. I then called every financial institution that I have an account with to set up a new, unique verbal password that they will ask me each time I call. Two banks required that I visit one of their local branches to set up the password in person. Another institution initially failed to set up my new password correctly. They continued to ask only for my social security number and mother’s maiden name until I escalated my case to a call center supervisor.

    After setting up these initial protections, I then submitted an affidavit to the Federal Trade Commission and visited my local police station to fill out a report. The latter allowed me to put a five-year freeze on my credit report with all three credit bureaus. I’ll have to jump through some additional hoops the next time I want a new credit card, but the freeze should make it much harder for a thief to open a new line of credit in my name.

    The time that millions of identity theft victims like me spend recovering from such cases each year isn’t insignificant. Microsoft’s Herley estimates that the time US consumers lose each year to simply maintaining existing passwords and other security measures runs in the billions of dollars.

    Yet, as inconvenient as it was, Schneier says my experience is, in fact, proof that the system works. “They caught it before anything bad happened. What more do you want?”

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 8:47 am on September 19, 2014 Permalink | Reply
    Tags: , , , , NOVA,   

    From NOVA: “Build Your Own Radio Telescope” 

    PBS NOVA

    NOVA

    Thu, 24 Jul 2014
    Tim De Chant

    In 2010, on the far northern part of New Zealand’s North Island, a satellite dish was unceremoniously decommissioned and scheduled for demolition. But thanks to pluck of a few scientists, the anticipated death of the dish ended up giving radio astronomy on the island new life.

    Lewis Woodburn, who is in charge of maintenance for Auckland University of Technology’s radio telescope, and his colleagues smelled opportunity when they heard of the decommissioning and convinced Telcom New Zealand to transfer ownership of the dish over to their department. At 30 meters, Telcom New Zealand’s dish was substantially larger than the 12-meter dish already operated by the university. If they could successfully repurpose it, the new, larger dish would boost their capabilities in radio astronomy.

    It wasn’t easy, though. Technology Review details their struggles in getting the 30-meter dish operational:

    What they inherited was a far cry from a state-of-the-art radio telescope. The dish is located near a remote township in the very north of New Zealand’s North Island. Being only five kilometers from the sea, salt corrosion was significant issue, particularly given the lack of recent maintenance.

    So the team’s first task was to clean the dish service and replace rusty bolts and equipment. In particular, the motors that move the dish had become rusted and in any case were old and inefficient.

    That’s not all; Technology Review’s Emerging Technology From the arXiv blog goes into more detail. After a series of refurbishment and upgrades, the new dish is finally a bonafide radio telescope, though it still needs a bit more work to give it the capabilities astronomers at Auckland University of Technology want.

    This clever repurposing of an old telecommunications dish led to an inevitable question: Can anyone build their own radio telescope? The answer, I discovered, is yes.

    carma
    CARMA Radio Telescope
    A DIY radio telescope won’t have the power of the CARMA Radio Telescope seen here, but you’ll have a view of the sky shared by few others.

    There are a few blog posts that detail people’s experiments with refitting old satellite TV dishes for radio telescope duty, but they vary in their level of detail. Fortunately, Jeff Lashley goes into great detail in a chapter titled “Microwave Radio Telescope Projects.” (pdf) He explains how to convert a compact satellite dish into a radio telescope and how to hook it up to software developed at MIT for a similar purpose. With all the parts in place, you can do things like observe radio waves emitted by the sun or study how the ionosphere affects those same emissions.

    A home-built radio telescope may not be as sensitive as the Very Large Array, but you’ll still be able to study the stars in ways few people can.

    NRAO VLA
    VLA

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 9:27 am on September 17, 2014 Permalink | Reply
    Tags: , , , , , , NOVA   

    From NOVA: “Chasing the Edge of the Solar System” Old But Worth a Look 

    PBS NOVA

    NOVA

    Tue, 09 Apr 2013
    David McComas

    For most of its lifetime, Voyager 1 has been traveling through uncharted territory. Initially launched to study the outer planets, Voyager 1 has soldiered on past Jupiter and Saturn and on to the outer edges of the solar system. It’s currently the farthest human-made object from Earth, but when will it be the first spacecraft to travel between the stars? Well, we won’t know until we answer two more fundamental questions: Where does our solar system end and the rest of the space between the stars begin? And if you were at the “edge” of our solar system, how would you know you had left? Recent scientific discussions on the Voyager spacecraft missions have captivated many people. And as the scientific debate swirled around the internet in near-real time, it became clear that these questions are not easy to answer. Voyager spacecraft
    The identical Voyager 1 and Voyager 2 are currently probing the farthest reaches of the solar system.

    NASA Voyager 2
    NASA/Voyager 2

    As the Principal Investigator for NASA’s Interstellar Boundary Explorer, or IBEX, spacecraft, I lead a team that is also studying this last frontier of our solar system. Data from IBEX complements the Voyager spacecraft—both missions are working together to find the very farthest reaches of the solar system. Unlike the Voyager spacecraft, which are careening out into interstellar space, IBEX orbits the Earth, collecting particles that have traveled in from the solar system’s boundary region and beyond. From those particles, we can determine many things, including what the boundary is like and what, exactly, is happening out there.

    NASA IBEX
    NASA/IBEX

    More Than Planets

    Most everyone knows our solar system is composed of small solid objects orbiting the Sun—planets, comets, and asteroids. But there’s more to it than that. Our Sun continuously emits a “wind” of material outward in all directions, typically at speeds of about a million miles per hour (1.6 million kilometers per hour). The solar wind is composed mostly of charged particles, such as electrons and protons. It also carries the Sun’s magnetic field. As the solar wind streams away from the Sun, it races out past all the planets, past Pluto, and toward the space between the stars more than 10 billion miles away. We tend to think of that space as empty, but it’s not. Rather, it contains cold hydrogen gas, dust, ionized gas, and traces of other material. Called the interstellar medium, it’s a very thin mix that comes from exploded stars and the stellar wind of other stars. When the magnetic fields of the solar wind hit the magnetic fields of the interstellar medium, they do not intermix. The expanding solar wind pushes against the interstellar medium, clearing out a cavity in interstellar space known as the heliosphere. The boundary of that bubble is where the solar wind’s strength exactly matches the pressure of the interstellar medium. We call it the heliopause, and it’s often considered to be the very outer edge of our solar system.

    The Heliopause.

    A few things about the heliopause: It isn’t an impermeable wall. Instead, it’s more like the edge of a forest clearing—the boundary is well defined, but easily negotiated. It’s also shaped more like a drop of water than a uniform sphere. That’s because our entire heliosphere, which contains our Sun, the planets, and everything else in our solar system, is moving through the interstellar medium at about 50,000 miles per hour (80,000 kilometers per hour). That motion creates a wake in the interstellar medium, much like a boat moving through water. As the solar system travels through the interstellar medium the heliopause is closest at the “front,” or the foremost point in the direction in which our solar system is traveling. At that point, the heliopause is still over 10 billion miles, or 16 billion kilometers, from the Sun.

    hh
    Heliosphere and heliopause

    As solar wind pushes out against the interestellar medium, it creates a bubble known as the heliosphere; the boundary between the two is known as the heliopause. The termination shock is where the solar wind slows as it presses against more of the interstellar medium, which also raises the plasma’s temperature. The bow wave is where the interstellar medium material piles up in front of our heliosphere, similar to water in front of a moving boat
    At least, that’s our best guess. We don’t know exactly where the boundary is or what it’s like. That’s what the IBEX and Voyager missions are trying to find out. IBEX lets us peer into the boundaries of our solar system to get a better idea of what it’s like and what’s happening there. However, because IBEX orbits the Earth, we cannot use it to mark where the boundary is located. That’s where Voyager 1 and 2 come in. Currently, they are directly sampling the boundary region. Several of the instruments on Voyager 1 and 2 are no longer working, including the cameras used to snap the stunning fly-by photos of Jupiter, Saturn, Uranus, and Neptune, but others that detect charged particles and magnetic fields are still gathering data. Both Voyagers are traveling in roughly the same direction as our solar system through the interstellar medium. We expect Voyager 1, the quicker and farther out of the two, to reach the heliopause first. Currently, it’s just over 11 billion miles, or 18 billion kilometers, from the Sun. This is so distant that radio signals from Voyager 1, which are traveling at the speed of light, take 17 hours to reach Earth.

    Three Criteria

    Before we can declare that Voyager 1 has crossed the heliopause, we are waiting to observe three main changes:

    A decrease in highly energetic charged particles from inside our heliosphere,
    An increase in highly energetic charged particles from outside our heliosphere,
    And a change in the strength and direction of the magnetic field, matching that outside the heliosphere.

    Voyager 1 observed the first two in late 2012, and IBEX has provided what are likely the best observations of the third. By using IBEX to look at particles that have traveled in from outside the heliosphere, we have an idea of the direction of the magnetic field beyond the solar system, and it’s very different from the Sun’s, which is carried out by the solar wind. So far Voyager 1 hasn’t observed this change direction of the magnetic field. That’s why we don’t think that Voyager 1 has crossed the heliopause—yet.

    The IBEX satellite orbits the Earth, capturing particles that have traveled into the solar system from beyond the heliosphere.
    Now, Voyager 1 has clearly passed into a new region of space, one that we have not detected before. Every new bit of data coming from the venerable spacecraft is teaching us more about this uncharted territory. All of this information is new, and we are learning more every day. So, do we know when Voyager 1 will cross the heliopause? We really have no idea. And that’s part of the fun. But learning about the edge of space is more than just an esoteric pursuit. Our heliosphere is a protective cocoon, a crucial layer of shielding against dangerous charged particles, known as galactic cosmic rays, that are harmful to living things. Understanding it will help us understand how the heliosphere has protected our solar system, enabling life to flourish on this planet we call home. And someday, that knowledge will help us prepare for our first voyage beyond the protective cocoon of the solar system, when we step across the threshold and venture into deep space.

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 1:28 pm on August 7, 2014 Permalink | Reply
    Tags: , Bacteria, NOVA   

    From NOVA: “This Bacterium Can Survive on Electricity Alone” 

    PBS NOVA

    NOVA

    21 Jul 2014
    Allison Eck

    Scientists are hoping that a large battery in a South Dakotan gold mine could lure curious forms of bacteria that may help us understand what powers life as we know it.

    That’s because scientists have begun to discover bacteria that live and thrive on electricity alone. Rather than mediating electrons through third-party materials (such as sugar or oxygen) like most organisms do, these bacteria transmit them unaccompanied by anything else. Understanding how these interactions work could give us a glimpse of the kind of life that might exist on other planets.

    bact
    Geobacter sulfurreducens breathes by transferring electrons to iron oxides found in soil.

    Here’s Catherine Brahic, writing for New Scientist:

    Unlike any other living thing on Earth, electric bacteria use energy in its purest form—naked electricity in the shape of electrons harvested from rocks and metals. We already knew about two types, Shewanella and Geobacter. Now, biologists are showing that they can entice many more out of rocks and marine mud by tempting them with a bit of electrical juice. Experiments growing bacteria on battery electrodes demonstrate that these novel, mind-boggling forms of life are essentially eating and excreting electricity.

    And scientists have found more than just a few new examples. Annette Rowe, a doctoral student at the University of Southern California, Los Angeles, has identified up to eight specimens demonstrating this behavior. That suggests to her advisor, Kenneth Nealson, that there could be a whole slew of organisms involved in direct extraction of electrons.

    While the immediate applications are obvious—for example, better biomachines (or self-powered devices) for human use—the findings could also tell us what life’s “bare minimum” is. In other words, at what amount of energy does life begin? And is it possible to create a bacterium that, through electric means, cannot be destroyed?

    Brahic again:

    For that we need the next stage of experiments, says Yuri Gorby, a microbiologist at the Rensselaer Polytechnic Institute in Troy, New York: bacteria should be grown not on a single electrode but between two. These bacteria would effectively eat electrons from one electrode, use them as a source of energy, and discard them on to the other electrode.

    Other-worldly expeditions to mines or deep-sea caves could help us find more examples of organisms that interact with their environments this way, thereby bringing us closer to answering some of these questions.

    See the full article here.

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 10:04 am on January 22, 2014 Permalink | Reply
    Tags: , , , NOVA   

    From Don Lincoln of Fermilab via PBS Nova: Journey Into the Dark Realm 

    nova

    Fermilab Don Lincoln
    Dr. Don Lincoln

    January 22, 2014

    After nearly a century of observations, astronomers have concluded that the type of matter that makes up you and me amounts to just a scant 5% of the recipe of the universe. A ghostly form of matter called dark matter is five times more common than our familiar atoms. True to its name, dark matter emits no light; we “see” it only indirectly, by measuring its gravitational pull on ordinary atoms. So how do we know it’s really there? To be sure, we need to detect dark matter directly.

    lux
    Photomultiplier tubes in the LUX dark matter experiment. Credit: Flickr/luxdarkmatter, under a creative commons license.

    Physicists have been searching for dark matter particles for decades now. Some experiments seem to have caught them while other, equally powerful experiments have failed to find any evidence for dark matter. Most recently, the ultra sensitive LUX detector, a vat of liquid xenon buried in a mile-deep underground lab, found no evidence for dark matter and ruled out earlier measurements that had reported hints of a signal. Does this mean one or more of these results is wrong? Not necessarily. There are ways for both the LUX measurement and earlier measurements to be true, but this requires that dark matter and ordinary matter interact with each other in very specific, unexpected ways. Scientists are exploring these possibilities.

    At the same time, physicists are beginning to think a bit more creatively. Until now, scientists looking for dark matter have imagined that dark matter is very simple. Specifically they imagine that there is just single type of dark matter particle: electrically neutral, experiencing only the weak and gravitational forces and with a mass 10-1000 times that of a proton. This model is popular because it is simple. On the other hand, the universe is not obliged to honor our definition of simplicity.

    Suppose someone was studying the behavior of ordinary matter using only gravity as a probe. They’d no doubt construct a simple model of matter as a particle that was something like a neutron. However, we know that our world is very complex, that the neutron is just one member of the particle zoo and that these particles can come together in all sorts of interesting ways. Scientists are beginning to wonder if maybe dark matter might be similar.

    Perhaps dark matter isn’t just one particle but a diverse realm of dark matter particles that experience forces that don’t affect ordinary matter. These dark matter particles might interact fairly strongly with each other, but only weakly with ordinary matter. With little experimental evidence to guide them, theoretical physicists are allowed to speculate fairly freely, although there are some constraints imposed by astronomical observations.

    One idea postulates a dark equivalent to electrical charge called “dark charge.” Just as ordinary electrons and positrons (antimatter electrons) can interact with each other and emit photons, it is possible that particles carrying dark charge can interact and produce dark photons.

    It is crucial to remember that dark charge, if it exists, does not interact with ordinary matter except by way of gravity and maybe the familiar weak force. A dark matter particle carrying dark charge and a familiar particle carrying electrical charge would pass by one another without so much as a “how do you do?”

    If a complicated dark sector exists, we can see it only if there is a particle that interacts with both ordinary matter and dark matter. If we could create such a messenger particle and allow it to interact with astronomical dark matter or (more likely) decay into dark matter particles, we might be able to detect it at particle accelerators like the LHC. But there’s a catch: The experimental signature would be “missing” energy in some collisions as the energy flowed into what physicists call the dark sector, the enigmatic realm of dark matter and dark energy. Given that disappearing energy is a fairly common feature of particle collisions (e.g. when neutrinos are created), it would be tricky to pin it on the creation of dark matter messenger particles. But by measuring the distribution of “missing” energy in LHC collisions and comparing it to the predictions of known physics and theoretical models of dark matter particles, it might be possible to catch a glimpse of the dark sector.

    Of course, missing energy is just one possible signature of a complicated dark sector. Another possibility invokes the principle of supersymmetry, which postulates that every known fundamental subatomic particle has a (so far undiscovered) cousin with a different quantum spin. Were the LHC to create these theoretical supersymmetric particles in a collision, they would decay into low-mass supersymmetric particles capable of interacting with the complex dark matter sector. After another cascade of decays, a dark matter particle could emit a messenger particle that “sees” both dark matter and ordinary matter and then decay in turn into a matter-antimatter particle pair that could be picked out in the collider data. Because this scenario postulates both supersymmetry and complex dark matter, it is even more of a jump into the unknown. But given that we don’t understand a lot of the universe, sometimes wild ideas are required. As Niels Bohr once quipped to Wolfgang Pauli, “We are all agreed that your theory is crazy. The question which divides us is whether it is crazy enough.”

    So far, physicists have not found evidence for a complex dark sector, but the search has just begun. Ordinary matter is complex, so it seems very reasonable that the dark sector should be, too. Over the next several years, theorists will begin to flesh out a myriad of dark possibilities, including possibly even dark atoms, just in time for the LHC to turn back on and see if the data supports these interesting ideas.

    See the full article here.

    Don Lincoln is a senior experimental particle physicist at Fermi National Accelerator Laboratory and an adjunct professor at the University of Notre Dame. He splits his research time between Fermilab and the CERN laboratory, just outside Geneva, Switzerland. He has coauthored more than 500 scientific papers on subjects from microscopic black holes and extra dimensions to the elusive Higgs boson. When Don isn’t doing physics research, he spends his time sharing the fantastic world of science with anyone who will listen. He has given public lectures on three continents and has authored many magazine articles, YouTube videos and columns in the online periodical Fermilab Today. His book “The Quantum Frontier” tells the tale of the Large Hadron Collider, the world’s preeminent particle accelerator, while his other book “Understanding the Universe” introduces the armchair scientist to particle physics and cosmology and tells how the two fields are intertwined.

    Fermilab Logo

    Fermilab Wilson Hall
    Wilson Hall at Fermilab


    ScienceSprings is powered by MAINGEAR computers

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 345 other followers

%d bloggers like this: