A “Completely Different Slant” on Solar System Formation

first_img51; “Did great balls of fire form the planets?” New Scientist asks.  A new theory “challenges the notion that the solar system started out as a placid sea of dust motes which simply clumped together to form planets.” If accepted, it “puts a completely different slant on what happened in the early solar system in the first 2 million years.”    Ian Sanders (Trinity College, Dublin) proposed that a nearby dying star with six times the mass of the sun sent asteroid-sized blobs of magma hurtling through the solar system.  Radioactivity kept the magma blogs molten.  This led to the formation of the enigmatic chondrules, which contain remnants of short-lived radioactive nuclides.  The colliding material also formed the building blocks of the planets.    Others find the idea intriguing but problematic.  The blobs should have differentiated into chemically distinct layers – not apparent in chondrules.  It also would impact beliefs about the origin and uniqueness of life.  PhysOrg quoted Dr. Maria Lugaro (Monash University), a member of the international team of astrophysicists who proposed the new theory.  “We need to know if the presence of radioactive nuclei in young planetary systems is a common or a special event in our galaxy because their presence affected the evolution of the first large rocks (the parent bodies of asteroids and meteorites) in the solar system,” she said.  “These are believed to be the source of much of earth’s water, which is essential for life.”This completely different slant is pretty oblique, all right.  So now Neil Armstrong and Buzz Aldrin should just accept the notion that, 40 years ago, they were starstuff walking on starstuff, just globs of protoplasm walking on old solidified globs of lava.  Assuming the hallmark of humanness is rationality, that sounds like one giant leap backwards for mankind.    While it’s nice to see some daring new thinking outside the box in science, this idea seems highly contrived.  The evolutionists probably won’t like it.  It makes the origin of the earth much more unlikely, for one thing.  For another, it tends to falsify the long-taught belief that dust accretion is sufficient to build planets.  But where is the evidence for a nearby large star in the right position with the right amount of material to seed our sun with planetary building blocks when they were needed?  How convenient to bring in the material by just-in-time special delivery.  Let’s ask the logical follow-up question.  Where did the dying star get its asteroid-sized blobs, if accretion is no longer in vogue?    “Great balls of fire” belongs in a rock concert, not a science lab.  This proposal should call into question whether imagining “notions” after the fact is really scientific.  Are scientists supposed to be sitting around inventing notions? (notion, n.: vague or imperfect conception or idea of something; a fanciful or foolish idea; whim).  You thought science was about testing theories with evidence.  The notion in this story amounts to little more than an ad hoc speculation concocted to save the old notion from anomalies.  There’s an ad hoc here and an ad hoc there, here a hoc, there a hoc, everywhere an ad hoc.  One doesn’t normally add hawks to the science farm.  If Old MacDonald Observatory ever hawks this theory, they should quickly hear some philosophical moos and oinks from the sentient animals.(Visited 17 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more

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Don’t Believe You Are the Best Salesperson

first_imgA salesperson who doesn’t believe that she is the best salesperson is better than the salesperson who believes that he is.Growing Through Your MistakesWhen you don’t believe that you are the very best, you are aware of your mistakes. You notice what you did wrong. You are honest with yourself when you analyze your performance. This willingness to believe that you make mistakes is what allows you to adjust and make changes that eventually improve your performance. It’s how we learn.The salesperson who believes that they are the very best isn’t aware of their mistakes, and so they make no adjustments. They aren’t honest with themselves or others. The salesperson’s willingness to lie to themselves prevents them from improving.Owning Your FailuresIf you don’t believe that you are the best, you accept responsibility for your failures. You don’t blame your failure on your prospect’s inability to perceive the value you create or your competitor’s lower price. You don’t blame your failures on the economy or some other factor over which you have no control. You don’t blame your sales manager or your territory. Owning your failures is what empowers you to do something different.The salesperson who believes that their failures are caused by something external disempowers themselves. Instead of owning their mistakes, they blame someone or something else. Blaming others is a recipe for sustaining poor performance.Taking Responsibility for Your Own GrowthThe salesperson who doesn’t believe that they know enough will take on personal and professional development projects. They will work to find areas where they need to know more, and they’ll work to learn it. They’ll find areas where they need to develop new choices and discover what other people are doing. They’ll model successful people’s beliefs and behaviors. This salesperson will find new opportunities.But the salesperson who knows everything cannot learn anything new. So they stagnate. Even if they knew a lot, as time passes, they fall behind. Instead of getting better over time, they start to slip and do worse.The salesperson who believes that they aren’t the best salesperson ever is willing to change. The salesperson who believes themselves to be the best is often the worst salesperson. Essential Reading! Get my first book: The Only Sale Guide You’ll Ever Need “The USA Today bestseller by the star sales speaker and author of The Sales Blog that reveals how all salespeople can attain huge sales success through strategies backed by extensive research and experience.” Buy Nowlast_img read more

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Inquiry finds merit in BJP leaders’ bid to ‘bribe’ Leh scribes

first_imgAn inquiry instituted into the bribe charges, levelled by local scribes of Leh against two top BJP leaders, has found “prima facie merit” in the allegations of attempt to pay money to “swing votes” in the Lok Sabha elections held on May 6.“We approached the district court on Tuesday through the police and sought directions for registration of an FIR in the matter,” Leh District Election Officer (DEO) and Deputy Commissioner Avny Lavasa said.She said the court is likely to club all three complaints, one from the DEO’s office and two others made by the Press Club Leh (PCL).Several journalists of the PCL in a written complaint against BJP’s state president Ravinder Raina and MLC Vikram Randhawa alleged these leaders tried to “offer bribe in envelops to swing votes”. The incident is also caught on a camera.“After a press conference on May 2, these two leaders tried to bribe the media persons by offering money in envelops in a bid to use our platform to influence the outcome of the elections,” seven journalists of the PCL wrote in the complaint addressed to the Station House Officer (SHO).Seeking First Information Report (FIR) against the BJP leader, the journalists said, “We showed our anguish at their attempt. The press fraternity of Ladakh strongly condemns the violation of the Model Code of Conduct.”The BJP said it will look into such allegations. “Our party has no such tradition. The party will look into it,” BJP state general secretary Ashok Kaul told The Hindu.last_img read more

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Another tour of duty for Schrock

first_imgDA eyes importing ‘galunggong’ anew ‘Rebel attack’ no cause for concern-PNP, AFP Ethel Booba twits Mocha over 2 toilets in one cubicle at SEA Games venue MOST READ Don’t miss out on the latest news and information. Still the main creative player for his club, Ceres-Negros, Schrock will link up with former club teammate Patrick Reichelt, who has been in fantastic form with eight goals so far for Melaka United in the first division in Malaysia.Schrock had hinted of retirement after scoring against Kyrgyzstan in a 3-1 loss during the group stage of the Asian Cup in the United Arab Emirates. But the midfield dynamo has decided to continue playing for the Azkals as he takes on the leadership mantle of the squad that won’t have longtime players Phil and James Younghusband. The Younghusband brothers have been without a club since last December and were not selected by Cooper.FEATURED STORIESSPORTSPrivate companies step in to help SEA Games hostingSPORTSPalace wants Cayetano’s PHISGOC Foundation probed over corruption chargesSPORTSSingapore latest to raise issue on SEA Games food, logistics US defense chief agrees it’s time to take another look at defense pact with PH PLAY LIST 01:46US defense chief agrees it’s time to take another look at defense pact with PH00:50Trending Articles02:27Another ‘ninja cop’ dismissed from service02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City01:07Trump talks impeachment while meeting NCAA athletes02:49World-class track facilities installed at NCC for SEA Games02:11Trump awards medals to Jon Voight, Alison Krauss LATEST STORIES Two-day strike in Bicol fails to cripple transport Cayetano: Senate, Drilon to be blamed for SEA Games mess Private companies step in to help SEA Games hosting ‘Healing’ POC meet set June 13 Asian Cup goal scorer Stephan Schrock has put on hold his plans to retire from international football as he joins the Philippine squad in its China training camp that includes a friendly against the Chinese national team on Friday in Guangzhou.Schrock, who skipped the training camp in Bangkok in March, was among the key returnees from the Asian Cup squad in January as coach Scott Cooper aims to put together the strongest lineup for the World Cup Qualifiers starting September.ADVERTISEMENT Sports Related Videospowered by AdSparcRead Next Duterte wants probe of SEA Games mess Catholic schools seek legislated pay hike, too View commentslast_img read more

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Whats New In Our 201718 Club Soccer Predictions

Costa RicaCONCACAF0.09-0.300.02 HondurasCONCACAF-0.61-0.61 SpainUEFA2.012.102.01 There aren’t too many surprises at the top; out of the five biggest European leagues, four are in the top five, with La Liga in Spain and the Bundesliga in Germany pretty far ahead of the pack. The Premier League in England, despite being the most valuable league in the world, has struggled to compete in the Champions League recently, and their match-based rating lags far behind their market value rating. Another league whose recent performance according to our ratings has lagged behind their market value is Major League Soccer in the U.S., whose last CONCACAF Champions League title was in 2000. MLS shows up in 28th place, between the Danish and Croatian leagues and a long way behind their regional rivals Liga MX in Mexico.To generate these league strength ratings, we’ve set up a system where we first assume that all leagues are of equal strength and determine how far above or below expectation each league has performed over the past five years. In order, we:Run through all domestic matches in history and calculate domestic team SPI ratings throughout time.Look at each inter-league match from the past five years and calculate the expected score of the match based purely on each team’s domestic rating at the time.Take the difference between our expected score of the match and the actual score and run these results through Massey’s Method to find a rating for each league, expressed in how many goals better or worse than average that league is.Regress these calculated ratings toward market-value based ratings, weighted by how many inter-league matches we have for each league.Run through all matches in history again, incorporating league strengths into the predictions for any inter-league matches to improve the final team ratings.Our league strengths can be interpreted as a bonus (in goals) given to each team in an inter-league match. So, for example, if Real Madrid (league strength of 2.01) were playing PSG (league strength of 1.48) and Real Madrid were a 0.2 goal favorite based only on their domestic SPI ratings, our model would give Real Madrid an extra 0.53 goal bonus because of the difference in the two teams’ league strengths.A nice feature of these league strength ratings is that they let us generate global SPI ratings for any club team in the world. These global SPI ratings are a combination of each team’s domestic SPI rating and the strength of the league they play in. To generate them, we set up a mock match on neutral ground against a team with a domestic offensive and defensive SPI rating of 1.35 that plays in a league with strength of 1.25. (These values are just arbitrary ratings that we use for a baseline team against which we can compare any other team.) We calculate the number of goals we expect each team to score in the match as well as the chances of each team winning. So each team’s global SPI ratings can be interpreted as follows:Offensive SPI: the number of goals the team is expected to score in such a matchDefensive SPI: the number of goals the team is expected to concede in such a matchOverall SPI: the percentage of points the team is expected to take in such a matchWe’ll be adding a list of all SPI-rated teams to our club soccer predictions soon. For now, you can find forecasts from 24 leagues. They’re available in three languages (English, Spanish and Portuguese) and will be updated after every match. Czech RepublicUEFA0.710.440.69 PortugalUEFA1.181.161.18 COUNTRY▲▼CONFEDERATION▲▼INTER-LEAGUE MATCHES▲▼MARKET VALUES▲▼OVERALL STRENGTH▲▼ HungaryUEFA-0.360.11-0.29 GermanyUEFA1.891.881.89 GreeceUEFA0.810.620.80 ItalyUEFA1.481.891.50 SwedenUEFA0.730.290.70 Not all leagues have market values on Transfermarkt.Sources: ESPN, Transfermarkt MaltaUEFA-1.65-0.63-1.44 COUNTRY▲▼CONFEDERATION▲▼INTER-LEAGUE MATCHES▲▼MARKET VALUES▲▼OVERALL STRENGTH▲▼ GuatemalaCONCACAF-0.64-0.64 IsraelUEFA0.220.230.22 NetherlandsUEFA0.711.050.73 IcelandUEFA-0.31-0.69-0.36 UruguayCONMEBOL0.600.150.58 BulgariaUEFA-0.150.27-0.10 BelgiumUEFA0.971.000.97 AustriaUEFA0.860.590.84 DenmarkUEFA0.590.380.57 MacedoniaUEFA-0.74-0.88-0.76 BoliviaCONMEBOL0.530.53 LuxembourgUEFA-1.41-0.84-1.29 WalesUEFA-1.60-0.88-1.46 PeruCONMEBOL-0.06-0.03-0.06 BrazilCONMEBOL1.481.641.49 ArgentinaCONMEBOL1.480.711.45 Faroe IslandsUEFA-1.70-0.88-1.54 STRENGTH BASED ON … CroatiaUEFA0.550.490.55 Relative strength of club soccer leagues from Europe, North America and South America, by countryBased on matches played in the past five years and the current market value of each league FranceUEFA1.511.011.49 ParaguayCONMEBOL0.900.90 ChileCONMEBOL0.740.180.71 KazakhstanUEFA0.400.270.39 EstoniaUEFA-1.67-0.52-1.47 ScotlandUEFA0.140.440.17 ArmeniaUEFA-1.05-0.42-0.92 RussiaUEFA1.491.271.48 AlbaniaUEFA-0.77-0.30-0.70 CyprusUEFA0.04-0.300.02 USACONCACAF0.540.660.56 AzerbaijanUEFA0.01-0.040.01 SwitzerlandUEFA1.070.751.06 Northern IrelandUEFA-1.63-0.88-1.48 BelarusUEFA0.150.020.14 TurkeyUEFA1.111.161.12 GeorgiaUEFA-0.79-0.30-0.71 MexicoCONCACAF1.120.931.09 ColombiaCONMEBOL1.020.460.99 All our significant changes are in how we assess the relative strength of domestic leagues. The goal was to improve our forecasts for the Champions League and Europa League and to better compare clubs in different countries — say, Juventus in Italy to Ajax in the Netherlands. We’re using recent matches played between teams from different leagues, supplemented with league market values (from Transfermarkt), to assign a strength rating to every league that we’re forecasting. Our new league ratings also give us the ability to a calculate a global Soccer Power Index (SPI) rating for each team — a number from 0 to 100 that represents the overall strength of each team.We’ll get into more detail about that methodology below, but to start, here are our league strengths for most of the top-tier domestic leagues in Europe, North America and South America: FinlandUEFA-0.45-0.38-0.44 This methodology article is for an old version of our club soccer forecasts. See how our latest club soccer predictions work.We’ve launched a big expansion of our soccer predictions here at FiveThirtyEight. We’re now forecasting 24 club soccer leagues, with two more — Champions League and Europa League — to come in a few weeks. We’ve added leagues from South America (Brasileirão and the Argentine Superliga), along with 14 new European leagues, including five second-tier leagues, such as the English Championship.For the most part, the methodology behind our forecasts is the same as last year’s. We’re still using four metrics from each match — goals scored, adjusted goals, shot-based expected goals and non-shot expected goals — to evaluate team performances. Those evaluations are expressed as offensive and defensive ratings for each team. And those ratings, in turn, let us calculate win/loss/draw probabilities for future matches and simulate the season thousands of times to estimate each team’s chances of winning the title. RomaniaUEFA0.750.240.71 SerbiaUEFA-0.110.12-0.09 EnglandUEFA1.582.281.60 El SalvadorCONCACAF-0.46-0.46 PanamaCONCACAF0.070.07 UkraineUEFA1.100.881.09 MontenegroUEFA-0.99-0.43-0.87 AndorraUEFA-2.79-0.88-2.25 VenezuelaCONMEBOL-0.09-0.11-0.09 LatviaUEFA-1.46-0.35-1.27 STRENGTH BASED ON … IrelandUEFA-0.28-1.07-0.40 BosniaUEFA-0.61-0.03-0.51 EcuadorCONMEBOL0.770.460.75 LithuaniaUEFA-2.08-0.43-1.69 SlovakiaUEFA0.19-0.160.15 PolandUEFA0.630.210.60 MoldovaUEFA-0.63-0.88-0.67 SloveniaUEFA-0.160.01-0.14 NorwayUEFA0.500.190.48 read more

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Ohio State mens basketball media day recap

The 2015-16 Ohio State men’s basketball season didn’t go as planned: that much is known. With only one junior on the roster and no seniors, leadership, experience and chemistry was a question.Perhaps going into the 2016-17 season, maturity and learning from last season’s second-round exit from the NIT could be OSU’s greatest asset.On Thursday afternoon, the Buckeyes held their annual media day inside the practice facility at the Jerome Schottenstein Center. OSU returns its six leading scorers from a season ago, looking to start a new trend of consecutive NCAA tournament berths — a streak that was snapped last season after seven straight appearances into “The Dance” from 2009-2015.The only returning member not available to the media was redshirt junior center Trevor Thompson. Coach Thad Matta and the rest of the returning Buckeyes fielded questions on the offseason and the upcoming 2016-17 campaign.Matta still hard on Buckeyes after last seasonSince taking over the OSU program in 2004, coach Matta has come to expect, and deserve, to be a top contender in the conference every year. Last season’s team simply didn’t come close to the requirements. Failing to make the NCAA tournament for just the second time in his 12 seasons in Columbus, Matta isn’t letting his players soon forget about it.“The biggest message (in the offseason) was we are going to fight for our culture every single day,” Matta said. “From the littlest of things, there’s going to be a demand of … we aren’t going to take anything for granted. We feel like we know what it takes to win here. I think we have the type of guys who are willing to do that.”Redshirt junior guard Kam Williams said when he misses a shot in practice, Matta shouts, “That’s how you end up in the NIT!” Albeit harsh, Matta said his sarcasm isn’t always understood by his players, but he said that has to be the mindset.When Matta took over the Buckeyes program, OSU was a middle-of-the-pack Big Ten team who often received a whomping by conferences powerhouses Indiana and Michigan State. Matta has been to two Final Fours, one national championship game, won five regular-season Big Ten titles, won four Big Ten Tournament titles and has won more games on the OSU sideline than any coach in school history.For all of that to return, he brought back former coaches Chris Jent and Alan Major to the staff, and Matta said he and the coaching staff have changed the structure of practice. Sophomore guard JaQuan Lyle said the players are being held accountable for their actions on the court and, most especially, off the court and in the classroom.“I don’t think we’ll be like we were last year just because we don’t want that feeling again,” Lyle said. “We remember that feeling after the Michigan State game (in the Big Ten tournament) when we knew we weren’t going to the (NCAA) tournament and then playing in the NIT. Nobody wants that feeling again.”Jae’Sean Tate ready to goThe junior forward underwent season-ending shoulder surgery to repair a torn labrum in his left shoulder in February. Tate also had a minor surgery in the offseason on his right ankle to remove a loose body that was bothering him for much of the season. Now just six weeks before the team leaves for Annapolis, Maryland, for its first game of the season against Navy, Tate says he’s fully recovered.“If we played today, I could play,” he said.Before Tate went down with injury, he was the undeniable leader on and off the court for a team that was hanging by a thread for an at-large berth into the NCAA tournament. Tate averaged 11.7 points and 6.4 rebounds per game in 2015-16. He said that not being able to finish the season last year is a chip on his shoulder he’s taking into this season.“I feel like we’re hungrier this year,” Tate said. “Going into it — especially me and (senior forward) Marc (Loving), he’s going into his fourth (year), I’m going into my third (year), I wasn’t able to finish the year last year and we still haven’t won. I’ve won at every level and I feel like to let Marc leave here without any awards, it just isn’t right.”Chris Jent making a differenceWhen assistant coach Jent left OSU after the 2012-2013 season, the Buckeyes just missed out on a Final Four appearance. Now Jent is back next to coach Matta on the sidelines and has been infectious thus far.“With coach Jent coming back, there’s a lot of basketball wisdom from higher levels of playing that guys want to reach here,” senior forward Marc Loving said. “He’s a high energy guy. He’s very passionate about the game. I felt like that just oozes out of him and translates to us, where guys want to get to the gym and are looking for times to get in and get a couple reps before class and after class. Just having him around is definitely a plus.”It’s no secret that Matta wants to get back to his winning ways at OSU. Recently he’s been criticized for letting in-state high-school talent leave the state for other top-notch programs, while OSU continues to be a middle-of-the-pack team in the Big Ten for the past three years. Junior forward Keita Bates-Diop said that Jent only knows OSU as a contender from his time as a player, from 1988 to 1992, and as a coach, so it’s natural for Jent to set high standards for this team.“That’s what he expects of Ohio State,” Bates-Diop said. “No matter who’s the coach, no matter who’s playing.”JaQuan Lyle, year twoJust like OSU’s season, the same can be said about sophomore guard JaQuan Lyle — there were some great moments, and some not so great moments. This season, however, Lyle is noticeably slimmer checking in at 210 pounds, looking to impose his will on the Big Ten and all of college basketball in 2016-17.“Me personally, I think I’m at a good place right now. (I have) pretty much doubled my basketball smarts from last year just off of having that one year under my belt,” Lyle said. “I think the biggest thing for me when the season starts is consistency. Being able to come out every night and compete. When my shot isn’t falling, still being able to do something.”Lyle occasionally showed the immaturity as a freshman, often times in big games. But in other instances, he would explode for a triple-double against Rutgers, 27 points on the road at Wisconsin and 29 points and eight rebounds at Indiana, among others. Consistency is undoubtedly a key for Lyle in his sophomore campaign, but he is attempting to channel the dominating player he knows he can be, which, in turn, might lead to a greater total in the win column.“I want to play more minutes than I did last year,” Lyle said. “I want to compete at a higher level than I did last year for a longer period of time. That really drove me to start getting my body right.” read more

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Track and Field Multiple Buckeyes set personal records at Meyo Invitational

Ohio State’s Cole Gorski celebrates in mid-air at the Simmons-Harvey Quad in Ann Arbor, Michigan, on Jan. 21, 2018. Credit: Ethan Clewell | Lantern ReporterMembers of both Ohio State’s men’s and women’s track teams set individual records in South Bend, Indiana, during the Meyo Invitational. The meet, which took place Friday and Saturday, consisted of 37 teams, professional athletes and unattached competitors. Ohio State did not send its full team, opting not to send throwers, jumpers and some sprinters.Men’s RecapOhio State senior Cole Gorski re-set his personal high in pole vault, clearing 5.45 meters Friday night. Gorski’s previous record of 5.40 meters was set at the Buckeye Classic, the first meet of the season.  Gorski finished second behind Nate Richartz, a recent Notre Dame graduate, who jumped 5.55 meters. Richartz was an All-American in indoor track last year.Junior Coty Cobb finished third in the event behind Gorski and Richartz with a vault of 5.15 meters.Sophomore Alexander Lomong took first place in the men’s 800-meter run with a race of 1:50. Lomong also joined freshman Paul Bete, sophomore Ryan Harrington and junior Luke Landis on the first-place team that set a season-high in the men’s distance medley relay with a time of 9:50.Women’s recapOhio State freshman Anavia Battle finished first in the women’s 60-meter dash with a time of 7:46. She ran the 200-meter dash in 23:79, also taking first. Ohio State owned the 200-meter dash. Senior Maggie Barrie finished third (24.43), senior Beatrice Hannan came in fourth (24.49) and sophomore Taylor DeLoach placed sixth (24.71).Barrie also had a second-place finish in the 400-meter dash with a time of 53.51.Senior Chantel Ray placed second in the 60-meter hurdles (8.32).In the 3000-meter run, senior Christine Frederick smashed her prior personal record by 11 seconds with a third-place finish at 9:24.Senior Madison Roberts also set a personal record Saturday in indoor pole vault, reaching 4.02 meters. She finished third in the event.Next weekend the Buckeyes will split up. Part of the team will head to Nashville, Tennessee, for the Vanderbilt meet and other Buckeyes will travel to Iowa City, Iowa, for the Iowa State meet. read more

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Train crushes 2 women to death

first_imgTrain accidentTwo women have been killed as they were hit by trains at Kosaibari area of Dakshinkhan and Khilkhet in the city.One of the deceased was identified as Nipa, wife of Swapan Mia of Dakshinkhan area while the identity of another woman could not be known yet.Sub-inspector of Airport Railway Station police out-post Nazrul Islam said a Noakhali-bound train hit Nipa while she was returning to her house from a relative’s house at Kosaibari, leaving her on the spot.Meanwhile, the unidentified woman was also crushed under the wheels of a train in Khilkhet area.Police recovered the bodies early in the morning and sent those to Dhaka Medical College Hospital for autopsy.last_img

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Researchers replicate supershear earthquakes in the lab

first_imgAerial photo of the San Andreas Fault in the Carrizo Plain, northwest of Los Angeles. Credit: Wikipedia. Citation: Researchers replicate supershear earthquakes in the lab (2013, June 7) retrieved 18 August 2019 from https://phys.org/news/2013-06-replicate-supershear-earthquakes-lab.html (Phys.org) —A team of geology researchers working in France has for the first time recreated the conditions in a lab that lead to a phenomenon known as a supershear earthquake. In their paper published in the journal Science, the researchers describe how they found that compressing granite under certain conditions caused ruptures to propagate faster than shear waves leading to an observable supershear event. Explore further Earthquake acoustics offer hint that a tsunami is imminent, researchers find More information: From Sub-Rayleigh to Supershear Ruptures During Stick-Slip Experiments on Crustal Rocks, Science 7 June 2013: Vol. 340 no. 6137 pp. 1208-1211 DOI: 10.1126/science.1235637ABSTRACTSupershear earthquake ruptures propagate faster than the shear wave velocity. Although there is evidence that this occurs in nature, it has not been experimentally demonstrated with the use of crustal rocks. We performed stick-slip experiments with Westerly granite under controlled upper-crustal stress conditions. Supershear ruptures systematically occur when the normal stress exceeds 43 megapascals (MPa) with resulting stress drops on the order of 3 to 25 MPa, comparable to the stress drops inferred by seismology for crustal earthquakes. In our experiments, the sub-Rayleigh–to–supershear transition length is a few centimeters at most, suggesting that the rupture of asperities along a fault may propagate locally at supershear velocities. In turn, these sudden accelerations and decelerations could play an important role in the generation of high-frequency radiation and the overall rupture-energy budget.center_img In a “normal” earthquake, seismic waves are generated as a result of faults in the Earth’s crust that rupture. At the same time, deep within the Earth, shear waves are generated that also propagate but are not felt on the surface. Shear waves tend to move much faster than seismic waves. Sometimes, though, in very rare instances, seismic waves gain a boost in speed and wind up propagating faster than sheer waves. The result is what geologists call a sonic-boom type of earthquake that can be far worse than its magnitude would indicate. Supershear earthquakes have been recorded occurring in nature just a few times, but until now have never been reproduced in the lab.To recreate the special conditions that lead to a supershear earthquake, the researchers subjected slabs of granite to very high pressure—pushing them together while also applying sideways pressure until they slipped against one another—releasing a wave of energy. It’s the same type of experiment used to study various types of earthquake conditions. In this instance, the researchers replicated the experiment 200 times—each time taking careful measurements with acoustic sensors. The team found that by manipulating the pressure exerted they could induce supershear like conditions. Their experiment was the first ever to succeed in recreating a supershear earthquake-like event in the lab. More importantly, it also shows that supershear earthquakes can occur at a much smaller level than researchers had believed. This means, they say, that such earthquakes should be able to occur much more often in the real world.The results obtained by the researchers aren’t a sign that people should worry, however, because it’s quite possible that the conditions in the lab were optimal for the creation of supershear earthquakes, most specifically the presence of smooth even granite surfaces—this is generally not the case in nature, and likely why they occur so seldom in the real world. The researchers suggest it’s possible that many supershear earthquakes happen in nature, but we don’t know about them because they occur in sections of faults that don’t move. © 2013 Phys.org Journal information: Science 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

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