Study explains why women are more prone to Alzheimers disease

first_imgThe study could help to explain why around two-thirds of dementia patients are female, a fact that has previously been attributed to women living longer than men and having more time to develop the condition. However, many scientists suspected that other mechanisms may be contributing to the gender gap in Alzheimer’s prevalence.The current study looked specifically at tau deposits in the brains of patients aged an average of 74 years who were all cognitively healthy. Women showed more tau in a region of the brain than men, which was associated with individuals with greater amounts of plaque deposits of the beta-amyloid peptide, another marker of Alzheimer’s.”Dr. Reisa Sperling, Lead Author By Sally Robertson, B.Sc.Feb 5 2019Reviewed by Kate Anderton, B.Sc. (Editor)Researchers at Massachusetts General Hospital have shed light on why women are more prone to developing Alzheimer’s than men.Carla Francesca Castagno | ShutterstockA study of 300 elderly individuals who underwent PET (positron emission tomography) scans showed that women are more likely to develop the toxic proteins known to trigger the disease.As reported in the journal JAMA Neurology, the scans revealed that men had fewer of the disease-causing tau and beta-amyloid deposits in their brains than women did.These proteins are present in all grey matter, but when large amounts of them aggregate to form tangles or clumps, this can destroy neurons and lead to memory loss and confusion seen in Alzheimer’s. Growing evidence suggests women may be at increased risk of certain physiological changes associated with Alzheimer’s disease.”Dr. Reisa Sperling, Lead Authorcenter_img These findings lend support to a growing body of literature that exposes a biological underpinning for sex differences in Alzheimer’s disease risk.”Dr. Reisa Sperling, Lead Author Researchers previously thought that there were no significant differences in the brain levels of these protein “biomarkers” between men and women, but potential gender-specific differences involved in the pathology of the disease is becoming an increasingly important focus in Alzheimer’s research.Sperling says the current findings support other studies in identifying potential reasons for the differences in risk for Alzheimer’s disease between men and women.Previous research has shown that women genetically predisposed to Alzheimer’s have higher levels of tau in their cerebrospinal fluid than predisposed men and the current study is the first to identify a similar pattern in clinically healthy individuals.last_img read more

Molecular target UNC45A is essential for cancer cell proliferation and tumor growth

first_img Source:http://www.augusta.edu/mcg/ Reviewed by James Ives, M.Psych. (Editor)Apr 19 2019Identifying a protein that plays a key role in cancer cell growth is a first step toward the development of a targeted cancer therapy. It is especially promising when this protein is dispensable for the growth of normal cells. Their discovery that UNC45A fits these criteria has researchers, led by Dr. Ahmed Chadli, of the Georgia Cancer Center at Augusta University, excited about potential new cancer therapeutic strategies involving the inhibition of UNC45A.UNC45A has long been recognized as a molecular chaperone, responsible for helping other proteins reach their functional state by guiding protein folding. It has a distinct role in cancer, however, where its over-expression in breast and ovarian cancer patient tissues correlates with grade and stage of the disease. After confirming that UNC45A is not required for the proliferation of normal breast cells, Dr. Chadli’s group showed that in both cell and mouse models of breast cancer, UNC45A is required for cancer cell proliferation and tumor growth.Related StoriesTrends in colonoscopy rates not aligned with increase in early onset colorectal cancerLiving with advanced breast cancerNanoparticles used to deliver CRISPR gene editing tools into the cellThey published the underlying molecular mechanism in the Journal of Biological Chemistry, first by demonstrating that when they silenced UNC45A expression, an enzyme called NEK7 was also down-regulated, by 2-fold. NEK7 plays a key role in cell proliferation by orchestrating the proper separation of chromosomes during cell division. Either silencing UNC45A or deleting NEK7 resulted in decreased cancer cell proliferation, and adding NEK7 to UNC45A-silenced cells restored proliferative capacity.Examining normal versus cancer cell lines and normal versus cancerous human breast tissues, the researchers observed significantly more UNC45A present inside (versus outside) of a cell’s nucleus. They further discovered that in the nucleus, UNC45A interacts with a protein called the glucocorticoid receptor that, in turn, promotes NEK7 expression.Due to NEK7’s key role in cell division, they further explored the effect of silenced UNC45A on cell replication. Importantly, they found that silencing UNC45A, which results in NEK7 down-regulation, caused the cancer cells to undergo what is known as mitotic catastrophe and die, exemplifying the ultimate therapeutic goal.This result was captured in a dramatic set of real-time videos of cell division in normal versus UNC45A-deficient cells. In normal cells (Movie 1), nuclear material, pictured in green, divides to form two separate cells, each surrounded by a cell membrane, which appears white. In UNC45A-deficient cells, (Movie 2), the nuclear material struggles to divide, and the division into two cells fails.”Inhibiting UNC45A holds tremendous potential in the fight against solid tumors, since its role in proliferation does not seem to be necessary for the survival of normal cells,” said Dr. Chadli. “How to inhibit its tumoral role apart from its normal functions is the topic of future studies that would improve our understanding of this molecular machine and how to harness its potential clinical application.”last_img read more

Global Facebook users to get good EUstyle safeguards Zuckerberg

first_img Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Facebook’s CEO Mark Zuckerberg said Europe’s history had made its citizens particularly wary when it comes to data collection © 2018 AFP Citation: Global Facebook users to get ‘good’ EU-style safeguards: Zuckerberg (2018, May 24) retrieved 18 July 2019 from https://phys.org/news/2018-05-global-facebook-users-good-eu-style.htmlcenter_img Facebook rolling out privacy choices under EU rules Speaking at the VivaTech trade fair in Paris a day before new European data protection rules come into force Zuckerberg said Europe’s history had made its citizens particularly wary when it comes to data collection.”There are specific points about history in Europe. If you’re a German citizen and you grew up here you’re worried about the Stasi (former East German secret police).”That’s more recent in your memory than what we have in the US or other folks around the world.”But “everyone cares about privacy. That’s not only here, that’s a global thing,” Zuckerberg said, confirming he would extend the protections demanded by the EU’s General Data Protection Regulation- including on facial recognition—to Facebook’s two billion users worldwide.”We’ve been very clear that we’ll roll out the same controls all around the world,” he said, adding that “good regulation” would increase user trust in how tech giants use their data.For weeks Facebook has been asking European users if they agree to be targeted by advertisers and allow Facebook to use a facial recognition tool on their photos and videos.It will now put those questions to all its users.”Starting this week, we’re asking everyone on Facebook to review important information about privacy and how to control their experience,” Erin Egan, the company’s privacy manager said in a statement.But while users in Europe must answer the questions to be able to access their accounts Facebook users in the rest of the world will be able to repeatedly skip the questionnaire.Zuckerberg’s remarks in Paris came two days after he apologised to European lawmakers for not doing enough to prevent the spread of fake news and the misuse of users’ information. Facebook CEO Mark Zuckerberg said Thursday that he was rolling out the privacy controls demanded by European regulators to Facebook users worldwide because “everyone cares about privacy”.last_img read more

Of course top job at Qatar Airways is held by a man

first_img Citation: ‘Of course’ top job at Qatar Airways is held by a man: CEO (2018, June 5) retrieved 18 July 2019 from https://phys.org/news/2018-06-job-qatar-airways-held-ceo.html © 2018 AFP Akbar Al Baker said his airline had taken steps to address gender equality, but when asked why it was led by a man, he replied: “of course it had to be led by a man because it is a very challenging position.”He later defended the carrier, saying it was the first Middle Eastern airline to have a female pilot and that other women were in senior roles.”We actually encourage women and we see that they have huge potential in… senior management positions,” Baker said at the close of IATA’s two-day annual meeting in Sydney—during which he was anointed chairman of the global industry body.”IATA also has a similar position on promoting gender equality.”The organisation currently has just two female CEOs on its 31-member board—Christine Ourmieres-Widener of British budget airline Flybe and Air Europa’s Maria Jose Hidalgo Gutierrez, who was added Tuesday.IATA’s chief executive Alexandre de Juniac acknowledged that having more women in senior positions was a “long-standing issue” that required further efforts from airlines and the industry body.It released figures in March showing just three percent of CEOs in the industry were female, compared with 12 percent in other sectors.Leading carriers in North America and Europe had the highest representation of women in senior roles at 16 percent and 14 percent respectively, IATA said.African, Asia-Pacific and South American airlines were at about eight percent, with the Middle East having the worst at four percent, the data showed.Qantas chief Alan Joyce said at the same press conference that the Australian carrier had achieved a strong turnaround in profits partly due to its pursuit of diversity, with women making up 40 percent of senior management.But he said it was “going to take a long time to fix some of the issues that are inherent in our society”, such as girls not studying science and technology in schools, which impacted their numbers in engineering and flying roles. Qatar Airways’ chief sparked disbelief Tuesday by saying his carrier was led by a man because “it is a very challenging position”—even as airline bosses admitted more women should be in top roles. Qatar Airways chief Akbar Al Baker sparked disbelief when he said his airline was led by a man because ‘it is a very challenging position’center_img Explore further Global airline body warns against protectionism, rising costs This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Bringing the heat out of the city

first_img Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. The water tunnel allows to analyse heat flows in cities. Credit: Swiss Federal Laboratories for Materials Science and Technology In order for the wind to dissipate the heat from the cities, however, the city must be built in such a way that air masses can flow relatively easily around the buildings. However, this is anything but trivial: there has not yet been enough research into how urban structures influence local wind conditions. In order to optimize cities in such a way that they can efficiently prevent the heat islands, one must first understand what exactly happens: How does the wind flow and swirl on buildings and over heated roads? And how does this change the temperature distribution? April 2018 showed temperatures in Switzerland that are usually more common in May—and in May the weather was already reminiscent of midsummer. This is no longer an exception. Year after year the heat records are being broken. Cities suffer much more from the heat waves than the surrounding countryside: the temperature differences between urban zones and the surrounding green areas can be as high as several degrees.The phenomenon is known as urban heat islands. There are several reasons for the temperature differences: The dark surfaces of pavements and rooftops absorb more sunlight during the day—and retain it better. Additional heat is generated in the city by traffic and industry. Furthermore, there is usually a lack of vegetation that could reduce the temperature by evaporation. And the closely spaced buildings block the wind, which could bring cooler ambient air.How can wind carry heat out of the city?The heat is not only unpleasant but also has severe effects: Energy consumption for cooling is increasing, ozone levels at ground level are rising and temperatures are leading to additional illnesses and even deaths. And more and more people are affected: Over half of the worlds population lives in urban areas today. By 2030, this percentage is expected to rise to two thirds. Cities and research groups around the world are working on ways to alleviate this urban heat island effect. Special attention is paid to the wind: it could dissipate the heat from the cities, bring cooler air from surrounding lakes and forests and additionally cool the surfaces by convection. During heat waves with little wind, the buoyancy effect plays an important role: when hot air rises above the city, cooler air can flow up below. In addition, areas with cooler air can be created: For example, parks with vegetation, lighter surfaces that absorb less solar radiation or surfaces where water evaporates—for example, artificial lakes or wet materials. The wind can distribute this cooler air in areas where the heat island effect cannot be fought locally. A matter of scaleAnswering these questions is the aim of the new water tunnel at Empa, which was officially inaugurated today. But why does it take a water tunnel to better understand wind movements? It is a matter of scaling: Since the models of urban structures are only a fraction of the size of real buildings and roads, water behaves exactly like wind in a real city at suitable flow speeds. The water tunnel has two clear advantages over a wind tunnel, which is also suitable for studying wind flows in cities: On the one hand, smaller models can be used, i.e. a larger area of the city can be examined. On the other hand, the flow field and the temperature distribution in the water can be measured simultaneously.This is done with a laser measuring system: the research team mixes tiny particles and a fluorescent dye into the water. The particles are illuminated with a pulsating laser beam extended to a plane. During such a laser pulse, a camera takes two images in rapid succession. The measuring system can now evaluate how far and in which direction the particles have moved between the two images and determine the flow velocities and flow directions. Thanks to the fluorescent dye, the researchers can determine the temperature distribution: It absorbs green laser light and emits light of a different colour—the warmer the water, the brighter the light. A second camera, which filters out the green laser light, records the emitted light distribution.The determination of the cool and warm flow structures allows researchers to gain new insights into how heat can be removed from cities. These results could help planners, architects and governments in the future to develop cities so that life in urban areas remains bearable even during increasing heat waves.center_img Heat waves are increasing worldwide—and that includes Switzerland. Cities in particular suffer as a result: the temperature difference between city and countryside can amount to several degrees. A new water tunnel at Empa could help to alleviate these urban heat islands in the future—for example by cities ensuring lower temperatures locally through vegetation, water surfaces and brighter materials and creating space for wind to aerate cities better. Provided by Swiss Federal Laboratories for Materials Science and Technology Citation: Bringing the heat out of the city (2018, June 18) retrieved 18 July 2019 from https://phys.org/news/2018-06-city.html Researcher considers structural measures to protect cities from extreme heat eventslast_img read more

Apple raises old iPhone tradein values to try and entice upgrades to

first_img Amid worries that iPhone demand is slowing and reports of Apple suppliers cutting revenue forecasts, Apple has upped its trade-in value for older iPhones for those looking to upgrade to its latest XR, XS and XS Max models using its GiveBack program.The new values, which extend to devices ranging from the iPhone 6 and 6 Plus all the way to last year’s iPhone 8, can net you anywhere between $150 for a 6 and $200 for a 6 Plus to $300 for a 7 Plus or an 8, assuming your phone is in good condition. For reference, prior to this boost, Apple was offering just $75 for an iPhone 6 and $100 for a 6 Plus.The iPhone 8 Plus and X are not receiving boosts in their trade-in values of $350 and $500, respectively.You would need to buy a new iPhone during the trade-in process to qualify for the increased value. If you aren’t buying a new phone, you will get the prior value in the form of an Apple Store gift card.At starting prices of $749 for the 64GB XR, $999 for 64GB XS and $1,099 for the 64GB XS Max, the extra credit quickly adds up to nice savings on a new phone, particularly for those on older 6 and 6S devices. But there are a few things to keep in mind.If you are planning to pay the full price for the new phone, good news: After you trade in your old iPhone—and Apple confirms it is indeed in the condition that you claimed—Apple will refund your credit card the value of the trade-in.The process works online or in an Apple Store, but the credit will be applied quicker in a store where you can trade in the old phone directly as opposed to shipping it in. Those who trade-in through a store will see the money returned to their credit-card accounts in three to five business days, while online trade-ins will take a few weeks as Brightstar, Apple’s partner for trade-ins, needs to evaluate it.If you want to pay off the new phone on a carrier’s monthly installment plan or through one of Apple’s iPhone payment plans you will have the trade-in value cover the taxes and fees for the new phone, with the difference being returned to you in the form of an Apple Store gift card.As this is an Apple Store gift card, and the processing companies for the monthly installments aren’t Apple but either a carrier or a third-party company Apple uses, you won’t be able to pay down the installments using the gift card.If you have other items you planned to buy from the Apple Store, such as AirPods, this gift card will still come in handy. But those looking for a discount and don’t want to spend hundreds of dollars immediately will still need to look elsewhere for a better deal. (c)2018 USA TodayDistributed by Tribune Content Agency, LLC. Credit: CC0 Public Domain Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.center_img Apple seems to have an upgrade problem and a new fix to try and entice upgrades. Citation: Apple raises old iPhone trade-in values to try and entice upgrades to new models (2018, November 28) retrieved 17 July 2019 from https://phys.org/news/2018-11-apple-iphone-trade-in-values-entice.html Apple is giving $50 refunds if you paid to replace your iPhone battery last yearlast_img read more

Shadow of 2 deadly crashes hangs over Boeings 1Q earnings

first_imgWhen Boeing releases first quarter results Wednesday, investors will be looking beyond profit and revenue numbers to clues about the fate of the company’s best-selling plane and when it might fly again. In this April 9, 2019, file photo a Boeing 737 fuselage, eventually bound for Boeing’s production facility in nearby Renton, Wash., sits on a flatcar rail car at a rail yard as a jet flies past overhead in Seattle. Boeing Co. reports earnings Wednesday, April 24. (AP Photo/Elaine Thompson, File) Boeing orders and deliveries tumble as Max jet is grounded When the market closed Tuesday, Boeing Co. shares stood 4% higher than before the October crash of a 737 Max operated by Indonesia’s Lion Air. After a slump, they skyrocketed from late December until early March when another 737 Max crashed, this one operated by Ethiopian Airlines.Analysts treated the Lion Air crash off the coast of Indonesia as a one-time event and noted confidently that Boeing was working on a software fix.Even with a mild sell-off since the March crash, the shares are still up 16% in 2019, barely trailing the 17% gain in the Standard and Poor’s 500.Investors believe the market for jetliners will remain strong for many years and airlines don’t have much choice for big planes—Boeing and Airbus form a duopoly, and both have huge order backlogs. CEO Dennis Muilenburg said the company has conducted 120 test flights of the upgraded software, and only needs a final certification flight with FAA personnel on board. That flight is expected any day.Last week, an expert panel of the Federal Aviation Administration judged that a software fix to the Max would be “operationally suitable,” and that airline pilots familiar with previous versions of the 737 won’t need additional time in flight simulators to learn about the new software that is unique to the Max. Citation: Shadow of 2 deadly crashes hangs over Boeing’s 1Q earnings (2019, April 24) retrieved 17 July 2019 from https://phys.org/news/2019-04-shadow-deadly-boeing-1q.html Explore further In this April 10, 2019, file photo a Boeing 737 MAX 8 airplane being built for India-based Jet Airways lands following a test flight at Boeing Field in Seattle. Boeing Co. reports earnings Wednesday, April 24. (AP Photo/Ted S. Warren, File) They’ll want to know how close engineers are to completing a fix to flight-control software at the center of investigations into two deadly crashes involving the Boeing 737 Max.Executives have so far given few clues about how much it will cost the company to fix the plane, compensate airlines whose Max jets are grounded around the world, and pay out claims to any of the families of the 346 victims.The aerospace giant is scheduled to release financial results for the first quarter before the stock market opens on Wednesday.Analysts surveyed by FactSet expect Boeing to report adjusted earnings of $3.19 per share on revenue of $22.94 billion. Both of those figures have come down considerably in the past month.Whether Boeing hits those numbers, however, will be secondary after the two crashes that have damaged the company’s reputation for safety, caused the worldwide grounding of about 370 Boeing 737 Max airliners, and raised questions about the U.S. government’s approval of the plane in 2017.Investigations into crashes in Indonesia and Ethiopia have implicated an automated flight-control system that erroneously pushed the noses of the planes down in response to bad readings from sensors. Boeing began working on a software update to the system more than five months ago. Jim Corridore, an airline analyst for CFRA Research, said that while Boeing still has much work to do, the FAA panel’s determination “shows that the return of the plane to flying is now a ‘when’ question rather than ‘if’ … we remain firm in our view that Boeing will survive this with its order book largely intact.”Some analysts do see long-term risks to Boeing, however. The company has temporarily cut production of 737s, which means cash will be delayed until deliveries of new planes resume. It also faces a growing list of lawsuits by families and shareholders.Goldman Sachs analyst Noah Poponak is surprised that investors seem to expect a “relatively benign” outcome of the Max saga.Airbus could raise production, Poponak wrote in a recent note to clients, and the flying public, airlines and several countries are viewing the Max with more caution.”We see a risk that lasts in the order book moving forward over the next few years,” he said. © 2019 The Associated Press. All rights reserved. In this April 9, 2019, file photo a Boeing 737 fuselage, eventually bound for Boeing’s production facility in nearby Renton, Wash., sits on a flatcar rail car at a rail yard in Seattle. Boeing Co. reports earnings Wednesday, April 24. (AP Photo/Elaine Thompson, File) This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Barry Becomes a Hurricane Barrels Toward Louisiana Coast

first_imgHurricane Barry is barreling northwest toward Louisiana, packing maximum sustained winds of 75 mph (120 km/h), with heavy rain, storm surges and dangerous winds expected along the northwest Gulf Coast. As of 11 a.m. ET, Barry was moving northwest in the Gulf of Mexico at 6 mph (9 km/h), and its eye was about 40 miles (65 kilometers) south of Lafayette, Louisiana, and about 50 miles (80 km) west of Morgan City, Louisiana. Hurricane forecasters expect the hurricane to lose strength over the next few hours, getting downgraded back to a tropical storm. The National Oceanic and Atmospheric Administration (NOAA) has issued a hurricane warning from Louisiana’s Intracoastal City to Grand Isle, meaning hurricane conditions are expected somewhere in that area over the next 36 hours or so.Headbutting Tiny Worms Are Really, Really LoudThis rapid strike produces a loud ‘pop’ comparable to those made by snapping shrimps, one of the most intense biological sounds measured at sea.Your Recommended PlaylistVolume 0%Press shift question mark to access a list of keyboard shortcutsKeyboard Shortcutsplay/pauseincrease volumedecrease volumeseek forwardsseek backwardstoggle captionstoggle fullscreenmute/unmuteseek to %SPACE↑↓→←cfm0-9接下来播放Why Is It ‘Snowing’ Salt in the Dead Sea?01:53 facebook twitter 发邮件 reddit 链接https://www.livescience.com/65932-hurricane-barry-barrels-toward-louisiana.html?jwsource=cl已复制直播00:0000:3500:35  Barry is expected to turn toward the north-northwest tonight, followed by a turn toward the north on Sunday (July 14), NOAA said. The center of the storm is forecast to move through southern Louisiana today and central Louisiana tonight. Then on Sunday, it should be churning through northern Louisiana, NOAA forecasts. “A lot of rainfall still yet to come out in the Gulf of Mexico,” NOAA National Hurricane Center director Ken Graham said during a Facebook Live at 11 a.m. ET. The rainfall will then start to impact portions of Louisiana, including New Orleans, he said. Because of the high winds, there’s a chance of tornadoes spinning off Barry. “A few tornadoes are possible through tonight across the southeast Louisiana, southern Mississippi and southern Alabama,” according to NOAA’s forecast. 5 Things Hurricane Sandy Changed for Good Originally published on Live Science.by Taboolaby TaboolaSponsored LinksSponsored LinksPromoted LinksPromoted LinksYou May LikeVikings: Free Online GamePlay this for 1 minute and see why everyone is addictedVikings: Free Online GameUndoTruthFinder People Search SubscriptionOne Thing All Liars Have in Common, Brace YourselfTruthFinder People Search SubscriptionUndoYahoo SearchYou’ve Never Seen Luxury Like This On A Cruise Ship. Search Luxury Mediterranean CruisesYahoo SearchUndoFinance101What Are The Best States To Retire In?Finance101UndoPrimeSolarQuotesCalifornia Signs Solar Law Helping Homeowners Save Hundreds A Month.PrimeSolarQuotesUndoGundry MD SupplementsTop Cardiologist: This One Thing Will Properly Flush Out Your BowelsGundry MD SupplementsUndo A History of Destruction: 8 Great Hurricanes Hurricane Katrina History and Numbers (Infographic)last_img read more

These Odd Quasiparticles Could Finally Unmask Dark Matter

first_img 9 Ideas About Black Holes That Will Blow Your Mind The 11 Biggest Unanswered Questions About Dark Matter The 18 Biggest Unsolved Mysteries in Physics About 80% of all the matter in the cosmos is of a form completely unknown to current physics. We call it dark matter, because as best we can tell it’s…dark. Experiments around the world are attempting to capture a stray dark matter particle in hopes of understanding it, but so far they have turned up empty. Recently, a team of theorists has proposed a new way to hunt for dark matter using weird “particles” called magnons, a name I did not just make up. These tiny ripples could lure even a fleeting, lightweight dark matter particle out of hiding, those theorists say. [The 11 Biggest Unanswered Questions About Dark Matter] The dark matter puzzle We know all sorts of things about dark matter, with the notable exception of what it is.Headbutting Tiny Worms Are Really, Really LoudThis rapid strike produces a loud ‘pop’ comparable to those made by snapping shrimps, one of the most intense biological sounds measured at sea.Your Recommended PlaylistVolume 0%Press shift question mark to access a list of keyboard shortcutsKeyboard Shortcutsplay/pauseincrease volumedecrease volumeseek forwardsseek backwardstoggle captionstoggle fullscreenmute/unmuteseek to %SPACE↑↓→←cfm0-9接下来播放Why Is It ‘Snowing’ Salt in the Dead Sea?01:53 facebook twitter 发邮件 reddit 链接https://www.livescience.com/65887-quasiparticles-could-unmask-dark-matter.html?jwsource=cl已复制直播00:0000:3500:35  Even though we can’t directly detect it, we see the evidence of dark matter as soon as we open up our telescopes to the wider universe. The first revelation, way back in the 1930s, came through observations of galaxy clusters, some of the largest structures in the universe. The galaxies that inhabited them were simply moving too quickly to be held together as a cluster. That’s because the collective mass of the galaxies gives the gravitational glue that keeps the cluster together — the greater the mass, the stronger that glue. A super-strong glue can hold together even the fastest moving galaxies. Any faster and the cluster would simply rip itself apart. But there the clusters were, existing, with galaxies buzzing around within them far faster than they should given the mass of the cluster. Something had enough gravitational grip to hold the clusters together, but that something was not emitting or interacting with light. This mystery persisted unresolved through the decades, and in the 1970s astronomer Vera Rubin upped the ante in a big way through observations of stars within galaxies. Once again, things were moving too fast: Given their observed mass, the galaxies in our universe should’ve spun themselves apart billions of years ago. Something was holding them together. Something unseen. [11 Fascinating Facts About Our Milky Way Galaxy] The story repeats all across the cosmos, both in time and space. From the earliest light from the Big Bang to the largest structures in the universe, something funky is out there. Searching in the dark So dark matter is very much there — we just can’t find any other viable hypothesis to explain the tsunami of data in support of its existence. But what is it? Our best guess is that dark matter is some kind of new, exotic particle, hitherto unknown to physics. In this picture, dark matter floods every galaxy. In fact, the visible portion of a galaxy, as seen through stars and clouds of gas and dust, is just a tiny lighthouse set against a much larger, darker shore. Each galaxy sits within a large “halo” made up of zillions upon zillions of dark matter particles. These dark matter particles are streaming through your room right now. They’re streaming through you. A never-ending rain shower o’ tiny, invisible dark matter particles. But you simply don’t notice them. They don’t interact with light or with charged particles. You are made of charged particles and you are very friendly with light; you are invisible to dark matter and dark matter is invisible to you. The only way we “see” dark matter is through the gravitational force; gravity notices every form of matter and energy in the universe, dark or not, so at the largest scales, we observe the influence of the combined mass of all these countless particles. But here in your room? Nothing. Unless, we hope, there’s some other way that dark matter interacts with us normal matter. It’s possible that the dark matter particle, whatever the heck it is, also feels the weak nuclear force — which is responsible for radioactive decay — opening up a new window into this hidden realm. Imagine building a giant detector, just a big mass of whatever element you have handy. Dark matter particles stream through it, almost all of them completely harmlessly. But sometimes, with a rarity depending on the particular model of dark matter, the passing particle interacts with one of the atomic nuclei of the elements in the detector via the weak nuclear force, knocking it out of place and making the entire mass of the detector quiver. Enter the magnon This experimental setup works only if the dark matter particle is relatively heavy, giving it enough oomph to knock out a nucleus in one of those rare interactions. But so far, none of the dark matter detectors around the globe have seen any trace of an interaction, even after years and years of searching. As the experiments have ground along, the allowable properties of dark matter have slowly been ruled out. This isn’t necessarily a bad thing; we simply don’t know what dark matter is made of, so the more we know about what it isn’t, the clearer the picture of what it could be. But the lack of results can be a little bit worrying. The heaviest candidates for dark matter are getting ruled out, and if the mysterious particle is too light, it will never be seen in the detectors as they’re set up right now. That is, unless there’s another way that dark matter can talk to regular matter. In a recent article published in the preprint online journal arXiv, physicists detail a proposed experimental setup that could spot a dark matter particle in the act of changing the spin of electrons (if, in fact, dark matter can do that). In this setup, dark matter can potentially be detected, even if the suspect particle is very light. It can do this by creating so-called magnons in the material. Pretend you have a chunk of material at a temperature of absolute zero. All the spins — like tiny little bar magnets — of all the electrons in that matter will point in the same direction. As you slowly raise the temperature, some of the electrons will start to wake up, wiggle around and randomly point their spins in the opposite direction. The higher you raise the temperature, the more electrons wind up flipped — and each of those flips reduces the magnetic strength by just a little bit. Each of those flipped spins also causes a little ripple in the energy of the material, and those wiggles can be viewed as a quasiparticle, not a true particle, but something you can describe with math in that way. These quasiparticles are known as “magnons,” probably because they’re like tiny, cute little magnets. So if you start off with a really cold material, and enough dark matter particles strike the material and flip some spins around, you’ll observe magnons. Because of the sensitivity of the experiment and the nature of the interactions, this setup can detect a lightweight dark matter particle. That is, if it exists. Paul M. Sutter is an astrophysicist at The Ohio State University, host of Ask a Spaceman and Space Radio, and author of Your Place in the Universe. Originally published on Live Science.by Taboolaby TaboolaSponsored LinksSponsored LinksPromoted LinksPromoted LinksYou May LikeVikings: Free Online GamePlay this for 1 min and see why everyone is addicted!Vikings: Free Online GameUndoTruthFinder People Search SubscriptionOne Thing All Liars Have in Common, Brace YourselfTruthFinder People Search SubscriptionUndoBeverly Hills MDTop Plastic Surgeon Reveals: “You Can Fill In Wrinkles At Home” (Here’s How)Beverly Hills MDUndoGundry MD Total Restore SupplementU.S. Cardiologist: It’s Like a Pressure Wash for Your InsidesGundry MD Total Restore SupplementUndoBirch Gold GroupThis IRS Tax Law is Sweeping the U.S.Birch Gold GroupUndoKelley Blue Book2019 Lexus Vehicles Worth Buying for Their Resale ValueKelley Blue BookUndolast_img read more