Israel Seeks AU Observer Status

first_imgIsraeli President Reuren Rivlin has asked Liberia, through President Ellen Johnson Sirleaf who is currently on a state visit to Israel, to see whether she could influence her colleagues in the African Union (AU) to grant Israel an observer status at the continental body. A report in the Jerusalem Post quoted President Sirleaf as saying that many African countries “have friends on both sides, and we have relationships on both sides,” referring to the Palestinian – Israeli conflict. She, however, pledged Liberia’s support, saying if there is a way to help, she would do so.“One of the things we all say is that we need peace in the world,” President Sirleaf told her Israeli counterpart.Liberia, along with other African countries, severed relations with the State of Israel in 1973 in the aftermath of the Yom Kippur War. The Yom Kippur War (also known as the Ramadan War and the October War) was a war between Israel and a group of Arab countries led by Egypt and Syria. The war took place from October 6-24, 1973. The war began on the Jewish festival of Yom Kippur in 1973, which corresponds with the Muslim month of Ramadan. The attack by Egypt and Syria was a surprise to Israel. Egypt’s army entered the Sinai Peninsula, and Syria’s army entered the Golan Heights.Although Liberia renewed its relationship with Israel in August 1983, the Liberian civil war of 1990 caused Israel to close its embassy in Monrovia. However, relations were upgraded following President Sirleaf’s election in 2006. During her visit recently, President Sirleaf commented on religious fundamentalism that is now plaguing the world, and informed the Israeli President that West Africa has been hit by terrorism, instigated by Muslim fundamentalists. “This kind of penetration by terrorists can undermine the peace we have had; and Liberia can benefit in this regard from any additional knowledge and intelligence that Israel has to offer,” she added.President Sirleaf previously visited Israel in 2007, and was in the country Tuesday to receive an honorary doctorate from the University of Haifa.According to a report by the Jerusalem Post, the two leaders discussed the long friendship between their countries, with President Sirleaf commenting that the relationship goes back to Israel’s very beginnings as a state. Liberia voted in favor of the partition of Palestine in the United Nations vote taken on November 29, 1947. The report described President Sirleaf as soft spoken and an extraordinarily influential woman, who has spent a couple of spells in prison on political grounds and who has served in senior positions at the United Nations, the World Bank and other prestigious financial institutions.“Her role models used to be powerful women such as Margaret Thatcher and Indira Gandhi, in whose footsteps she followed until she ran into Nelson Mandela,” the newspaper wrote about President Sirleaf’s past struggles for justice and democracy in Liberia.With reference to Nelson Mandela, President Sirleaf said, “He made us more conscious of humanity. We have tried to bring back some of the freedoms lost during years of militancy and conflict.”The paper made further reference to the Ebola crisis, and noted that Ebola was more than a health crisis for Liberia. It also affected the country’s economy. Many investors left the country and it is now going through a period of re-growth.“Similarly, during the years of conflict as well as the health crisis the educated class left the country, and Liberia is now in the process of rebuilding its education system,” the newspaper reported.“The challenges are many, but we continue to be resilient,” Madam Sirleaf was quoted as saying.Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)last_img read more

Critical role and necessity of the LGC cannot be understated

first_imgDear Editor,For more than two years, this column has vociferously advocated for the establishment of the Local Government Commission (LGC). Indeed, we embrace and recognise the contributions of other commentators who have called daily for Government to act on this crucial Commission over the past months.The critical role and necessity of the LGC cannot be understated! There were seeming objective crafting of bills and many amendments to relevant local government legislation leading to the 2015 General and Regional Elections, to address improvements to local governance. These were seen as necessary by both the then Government and Opposition. Even President David Granger when he was Leader of the Opposition, made strong calls on the People’s Progressive Party/Civic Government to appoint the Local Government Commission.There are serious problems in the Local Government System! Staffing matters as one issue is too numerous to detail, although much mention was previously made of the A Partnership for National Unity/Alliance For Change’s (APNU/AFC) inaction towards its contaminating and destabilising effects. As a consequence, the elected councils are finding it extremely difficult to deal with non-performance and the new level of indiscipline emerging in the Local Authority Areas (LAA).The serious and un-ending problems at the Regional Democratic Councils and Neighbourhood Councils can be easily solved at the level of the LGC.As it is now, Bulkan’s Ministry is providing direct biased monitoring and controlling oversite over Local Authority Areas. This is because of the APNU/AFC’s significant loss at the 2016 Local Government Elections, and it is clear that the various councils cannot function efficiently without the LGC. Observably, this APNU/AFC Administration relishes the dictatorial and authoritative free for all way. This is in order for them to do whatever they wish, without informing the residents or their elected representatives.Most recently, we observed published articles about the ugly invasion by the Communities Ministry to facilitate the relocation of some squatters within the Mocha Arcadia NDC without consultation; this is the workings of the same Ministry that has the responsibility to appoint the LGC. It makes it clearer that the coalition Government does not have any respect for the views of community leadership. It must also be noted that other sections of the population are doing what they want without consulting the relevant elected bodies.Some private citizens and organisations are also moving in the communities and doing what they want without consultation.More seriously is the fact that the Private Sector bodies are moving in with their money and just pay off some people, build and do whatever they want, given the depreciated support to the elected councils by the Government.This lawlessness is leading to extreme levels of corruption, facilitated the Government.The local government system must be allowed to function in the interest of the people who elected the leaders!The Local Government Commission must be appointed now!Sincerely,Neil Kumarlast_img read more

Former Navy quartermaster remembers combat in Pacific during World War II

first_img“He’s always telling all the kids, the grandkids, anyone who will listen,” the 72-year-old said. “Join the Navy and see the world” – that was promotional slogan that had Bernard Leyva hooked at 20. As a young Los Angeles native living in Upland and working as a statistical draftsman for the U.S. Army, Leyva said he wanted to be all he could be at the height of World War II. “I didn’t want to be drafted, I wanted to join up myself,” he said. Leyva enlisted in the Navy in November 1943 and after two months of boot camp, went for special training to become a quartermaster. “I used to assist the ship’s navigating officer,” he said. As a quarter master, he also plotted courses, used magnetic compasses and trained in Morse code. “I stood a lot of watches up on the bridge,” Leyva said. “When we were in the South Pacific, I would go up on watch for eight hours, then rest 16 hours, then go up again for another eight hours.” It was on one of those watches in 1944 that Leyva had his first close encounter with a Japanese kamikaze suicide plane. “I looked through \ and way up high I could see the Japanese planes flying around,” he said. “They spotted us and they were going to try to get us.” Leyva warned his commanding officers immediately, who then ordered the ship push forward at full speed and on a zigzag course. “One plane came by and I could see the bullets hitting the water,” he said. But the “Lucky Lang” – as it was nicknamed – was never hit. No one on board was ever injured during the war. “They would try to send up other destroyers to help us \but they all got hit,” he said. “Our ship was unscathed. I don’t know. God was with us I guess, but I didn’t get it.” During his time in the Navy, Leyva and the Lang engaged in several assignments including sweeping for mines along the Philippine coast and helping to protect transporter ships – with thousands of soldiers on board – reach Japanese shores safely. In the spring of 1946, Leyva’s ship was ordered to return to Hawaii and San Francisco to load up supplies. His men never returned to the war zone. “We were just about to head back out to joint the fleet when Japan surrendered,” he said. “I was relieved. I knew if we went back, it was going to be the most fierce battle.” The USS Lang was sent to Brooklyn for decommissioning. It was then that Leyva made the decision to disobey orders and keep the ship’s American flag. “He went in a kid and came out a man,” Marie Leyva said, adding that she always thought her husband should have made a career in the Navy. Instead, Bernard Leyva returned to his trade as a draftsman up until his retirement in 1990. “It was so long ago now, it just seems like a dream, almost like a dream,” he said of the war. But the encased flag and the abundance of memorabilia remind him it was real. “I was so proud, proud to have served,” he said. “We fought for freedom.” tania.chatila@sgvn.com (626) 962-8811, Ext. 2109 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! The flag had served as emblem aboard the USS Lang – the 1,500-ton destroyer ship Leyva called home for nearly three years during Word War II. “That flag flew from Ulithi to Okinawa to San Francisco,” the 84-year-old said. “It meant a lot to me.” It now sits in a special case in the Mexican-American’s Whittier home office. In the small room – where two of Leyva’s sons used to sleep – is an abundance of war and Navy memorabilia. It doesn’t surprise Leyva’s wife, Marie, who admits her husband of about 40 years uses every chance he gets to talk about his time in the service. • Video: 7/07: WWII Veteran Bernard LeyvaWHITTIER – For nearly six months before being honorably discharged from the Navy, Bernard Leyva hid a tattered, worn American flag at the bottom of his sea bag. The former third class quarter master had originally been ordered to deliver the flag for proper disposal more than 60 years ago. But it was an order Leyva did not follow. last_img read more

Fans hit out at Van Gaal after Dutchman brings on Phil Jones when 2-1 down

first_imgWhen Manchester United were 2-1 down at Bournemouth, desperate times called for desperate measures. The Cherries were leading with thanks to goals from Junior Stanislas and Josh King, while Marouane Fellaini netted for the Red Devils in talkSPORT’s live commentary match. United were famous for ‘Fergie time’ under Sir Alex Ferguson’s reign, but Louis van Gaal’s luck does not seem to be in at the moment. With Man Utd about to extend their winless run to five in all competitions, Van Gaal looked to his bench. He had attacker Ashley Young available and even Morgan Schneiderlin, but instead he replaced Paddy McNair with defender Phil Jones in the 91st minute.That decision did not go down well with Manchester United – and football – fans, who took to Twitter to vent their frustration and mock the Dutchman’s decision. See below! The pressure is increasing on Louis van Gaal 1last_img read more

Stoke to field strong team v Bristol City as Mark Hughes plots Carabao Cup run

first_img1 Stoke manager Mark Hughes intends to name a strong line-up against Bristol City as the Premier League club look to avoid becoming a Carabao Cup scalp.The Potters saw a four-match unbeaten run ended with a 2-1 defeat at Newcastle on Saturday.While Hughes is set to have one eye on the weekend’s home Premier League clash against Chelsea, the Stoke boss will give Tuesday night’s Championship opposition the utmost respect as they aim to reach the last 16.“There are a couple of players we feel we need to give a game, but we will still go strong,” Hughes said on the club’s official website.“It is important that we progress in the competition, so we want to have a good run in it this season if we can.”Captain Ryan Shawcross and fellow defender Geoff Cameron are both working on their recoveries from injury problems which kept them out of the match against Newcastle so are not expected to be involved against the Robins.Defender Glen Johnson, midfielder Charlie Adam and striker Peter Crouch, though, could all be drafted into the starting XI as Hughes looks to freshen up his team.Kurt Zouma should also be involved as the French defender will not be eligible to face parent club Chelsea in the Premier League on Saturday under the terms of his loan deal.Hughes said: “Kurt Zouma can’t play on Saturday against Chelsea so he will be involved and we will go there with a team strong enough to give it a really good go.” Mark Hughes last_img read more

Ronny Deila: Celtic showed future of club in Motherwell thumping

first_img“It was perfect,” he said. “It was like you had dreamed of. “A very good performance, a young team out there who I think is the future of this club, it was 7-0, a sunny day as well, which is not often and a very good atmosphere as normal so it was a perfect ending for me.“It is a very tough day. It is hard to speak about it to be honest. I am grateful to have been here.“I learned so much in two fantastic years. I am going to enjoy the new life now. “There are going to be new opportunities, but these two years will always be special to me but right now it is too much to take in.” Ronny Deila hailed the “perfect” sendoff as Celtic manager, highlighting that the Hoops’ emphatic display against Motherwell showed the future of the club.Kieran Tierney, Ryan Christie and Jack Aitchison all scored their first goals for the Hoops as the already crowned Scottish Premiership champions put seven past the Steelmen.Deila took the acclaim of the supporters after full-time at Parkhead with the Norwegian now leaving the club after a disappointing season.He reflected on his two-year stint as Celtic manager and insisted that the win over Motherwell showed that the club’s future is a bright one.last_img read more

Hearts open talks with Ian Cathro and Austin MacPhee

first_imgHearts also hope to swoop in on Scottish FA target MacPhee has been linked with the performance director role.The move would see 30-year-old Cathro team up with Craig Levein again after working with him at Dundee United when he was head of the club’s youth academy between 2008 and 2012. He then coached at Rio Ave in Portugal before assisting at Valencia for one season. He was also involved in the SFA’s youth development under Mark Wotte. The appointment of MacPhee would see him move back into coaching in Scotland after previous spells at Cowdenbeath and St Mirren. Hearts have opened talks with Newcastle over Ian Cathro as they look to fill their vacant head coach role.The Tynecastle side want the young Scot to team up with Northern Ireland number two Austin MacPhee as the club’s new coaching team after Robbie Neilson joined English League One side MK Dons last week.STV understands there are no other candidates and the club hope to appoint the pair this week.The job would see Cathro, who is currently Rafa Benitez’s assistant at Newcastle, take charge of a club for the first time in his career after years of coaching in England, Spain, Portugal and Scotland.last_img read more

Women in Science Work for Less Money

first_imgStudy hard, receive a science or engineering degree, and your reward will be a well-paying job in your chosen field. That’s part of the sales pitch for those trying to attract more women into science. But according to a new U.S. government study, the “reward” includes earning 12% less than your male counterparts. The 11-page report, “Women in STEM: A Gender Gap to Innovation,” is the first analysis of women working in technical fields (STEM stands for science, technology, engineering, and mathematics) by the Commerce Department’s Economics and Statistics Administration (ESA). The study is based on data from the 2009 American Community Survey, an ongoing questionnaire by the U.S. Census Bureau that supplements the decennial census. The report’s overall conclusion that women are underrepresented in the U.S. STEM workforce — holding 24% of all STEM jobs while comprising 48% of all workers — won’t be a surprise to anyone who follows the issue. But they may find the lack of progress depressing: “Over the past decade, this underrepresentation has remained fairly constant, even as women’s share of the college educated workforce has increased,” explains a departmental press release on the report, released yesterday. Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*) Acting Commerce Secretary Rebecca Blank, a Ph.D. economist who oversees both ESA and the Census Bureau, tried to put the best spin on the salary disparity between men and women in STEM fields. “There is a gender earnings gap across the economy,” she told reporters. “But it’s actually smaller in STEM areas than in non-STEM areas.” Still, she acknowledged that the salary gap raises larger questions. “In fact, one might think that the smaller [salary] gap might actually draw women into STEM jobs. So it adds to the puzzle of what is it that we are doing inside our schools and our families that makes STEM jobs seemingly less attractive to girls.” Blank said the survey didn’t analyze the gender salary gap by work setting, such as industry versus academia. “But we did look at the gap by occupations,” she notes. “And what’s interesting is that engineering, which has the lowest percentage of women, actually has the smallest gender gap. It’s only 7 cents.” She said the gender earnings gap “is one of the big research questions in economics. Why does it exist, even after you control for presumably what are all of the productivity attributes?” Even so, she’s willing to hazard a guess. One answer, she says, is that “women don’t seem to get the same number of promotions and wage increases as men do.”last_img read more

LEDs created from wonder material could revolutionize lighting and displays

first_img N. Zhou et al., Sci. Adv. 5, EAAV8141 (2019) LEDs created from wonder material could revolutionize lighting and displays By Robert F. ServiceJun. 4, 2019 , 4:45 PM When combined with polarizing filters, 3D-printed perovskite nanowires produce adjustable multicolor displays. In solar cells, the cheap, easy to make materials called perovskites are adept at turning photons into electricity. Now, perovskites are turning the tables, converting electrons into light with an efficiency on par with that of the commercial organic light-emitting diodes (LEDs) found in cellphones and flat screen TVs. And in a glimpse of how they might one day be harnessed, researchers reported last week in Science Advances that they’ve used a 3D printer to pattern perovskites for use in full-color displays.“It’s a fantastic result, and quite inspirational,” says Richard Friend, a physicist at the University of Cambridge in the United Kingdom whose team created the first perovskite LED in 2014. The result raises hopes that the computer screens and giant displays of the future will consist of these cheap crystalline substances, made from common ingredients. Friend cautions, however, that the new perovskite displays aren’t yet commercially viable.The materials in current semiconductor LEDs, including the organic versions, require processing at high temperatures in vacuum chambers to ensure the resulting semiconductors are pristine. By contrast, perovskites can be prepared simply by mixing their chemical components in solution at room temperature. Only a brief heat treatment is needed to crystallize them. And even though the perovskite crystals end up with imperfections, these defects typically don’t destroy the materials’ ability to emit light.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)In most perovskite LEDs, electrodes sandwiching the light-emitting material deliver charges—negatively charged electrons and positively charged electron vacancies. When the charges meet at the center of the sandwich, electrons fill the vacancies and give up a bit of their energy as a photon of light.The color of the photon depends on the perovskite’s chemical constituents, enabling researchers to tune the color by changing the perovskite’s recipe. The Cambridge group’s first perovskite LEDs glowed near-infrared, red, or green, depending on their makeup. Since then, the team and other groups have made a full spectrum of colors.The earliest perovskite LEDs converted only 0.76% of electrons into photons. That’s because electrical charges moving through the material got stuck at the boundaries between the myriad crystallites making up the material. But numerous teams have overcome that hurdle. Late last year in Nature Photonics, for example, Friend’s group reported that by adding a light-emitting polymer layer that helps steer charges around the surface defects, it had made red perovskite LEDs with an efficiency of 20.1%.A team led by chemist Edward Sargent at the University of Toronto in Canada took a different approach last year, spiking its perovskite recipe with an additive that formed crystalline shells around the perovskite crystallites. The shells blocked the defects from trapping charges, resulting in a green perovskite LED with 20.3% efficiency, the team reported in Nature. That remains well below the efficiency of many inorganic LEDs, but is probably good enough for some applications.Researchers led by Feng Gao, a physicist at Linköping University in Sweden, reported online on 25 March in Nature Photonics that they developed yet another way to tackle the defect problem. They targeted the tendency of lead ions at the edges of perovskite crystallites to trap passing electrons. With an additive that bound to the lead, they reduced the ions’ hunger for electrons and created a near-infrared LED that had 21.6% efficiency.The pace of improvements in the past 5 years has been “quite exceptional,” Friend says. Still, none of the perovskite devices survives more than about 50 hours, well below the estimated 10,000 hours needed for commercial use. Just why the perovskite crystals fall apart after a few dozen hours isn’t clear, Gao says. But short lifetimes also plagued early organic LEDs, he notes. And perovskite solar cell–makers have largely solved similar longevity issues by protecting their devices from air and humidity. “I’m optimistic this area can also develop quickly, and perovskite LEDs can improve,” Gao says.If they do, the latest work from researchers led by Jennifer Lewis, a materials scientist at Harvard University, could point to new strategies for constructing displays. Lewis and her colleagues used a 3D printer to arrange tiny, wire-shaped perovskite structures in multicolor displays. As the “ink” carrying the nanowires passed through the printer nozzle, shear forces aligned them, Lewis says. The common orientation of the nanowires gave light from each LED a single preferred oscillation, or polarization.For their prototype displays, Lewis’s team didn’t wire each LED to electrodes; instead, the researchers exposed the entire display to ultraviolet (UV) light. Like an applied electric voltage, the UV light kicks electrons out of their normal state, allowing them to move. Then, they can recombine with vacancies and emit visible light. But because the emitted light was polarized, Lewis and her colleagues could use polarizing filters to control it.In one example, the researchers used three different perovskite formulations to create displays in which each pixel contained a red, green, and blue spot side by side, with the orientation of the nanowires in each spot offset by 60°. By rotating a polarizing filter, the researchers could mix colors or isolate a single color.Plenty of hurdles remain for perovskite LEDs, Sargent says. But he adds, “This work jumps ahead 10 years in the future and shows what cool things we can do.”last_img read more

Red Bull’s Max Verstappen tops practice session at Chinese Grand Prix after mist forces abandonment of first practice

first_imgThe opening practice session for the Chinese Formula One Grand Prix was halted twice then abandoned because the medical support helicopter was unable to operate in poor visibility on Friday.The 90-minute session was finally called off with five minutes remaining on the clock at a drizzly and misty Shanghai International Circuit. (Also read: Australian GP winner Sebastian Vettel tips Mercedes as favourites for Chinese Grand Prix)Fourteen drivers set a time during the brief window of track action, going out on a mix of intermediate and wet-weather tyres. (Also read: Mercedes have to raise game to meet Ferrari challenge, says Lewis Hamilton)Teenager Max Verstappen was fastest in his Red Bull, lapping the 5.4-kilometre circuit in one minute, 50.491 seconds.The Dutchman’s time was more than 15 seconds slower than Nico Rosberg needed to secure pole position for last year’s race, an indication of the limited usefulness of the curtailed session.Championship favourite Lewis Hamilton, who heads into Sunday’s race determined to strike back against a resurgent Ferrari by racing to a fifth win in China, did not set a time in his Mercedes.German Sebastian Vettel, winner of last month’s season-opener in Australia, did not set a time either, with his Ferrari team mate Kimi Raikkonen also limiting himself to a single installation lap.Several drivers were caught out by snaps of oversteer in the cool and damp conditions. Most got going again but Nico Hulkenberg beached his Renault in the gravel, returning to the pits on the back of a scooter.advertisement”The weather conditions have forced the closure of the local airport,” read a message on the timing screens.The first suspension was prompted by the medical helicopter being unable to land at the designated hospital in Shanghai, while a message on the timing screens when the session was halted for the second time said the “local airport” had been closed.Television helicopters continued to hover above the circuit throughout.last_img read more