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Material gain

first_imgScientists from Harvard University and the Massachusetts Institute of Technology have developed a theoretical model of a material that one day could anchor the development of highly efficient solar panels.Traditional organic solar panels work by combining photons with light-sensitive materials, creating particles called excitons. Those particles are then channeled through the material to an interface, where they dump energy into electrons that flow along wires, producing electricity. The problem is that excitons aren’t easy to control. The particles are often trapped by defects in the material, and release their energy as light, reducing the efficiency of the panels.Inspired by cutting-edge theories in condensed matter physics and the development of quantum computers, the Harvard-MIT group used magnetic fields to force excitons to move in a specific direction, avoiding the traps that plague traditional materials. The system is described in a paper in Nature Materials.The research team was led by Professor of Chemistry and Chemical Biology Alan Aspuru-Guzik and included Joel Yuen-Zhou, a former Ph.D. student in Aspuru-Guzik’s lab who is now a postdoctoral fellow at MIT, and research associate Semion Saikin.“This effect has been identified in physics, in what’s called the quantum Hall effect, and in topological insulators, but we believe this is the first time this has been proposed in a practical way for excitons in molecular layers,” Aspuru-Guzik said. “What we wanted to ask was, can this be done in organic materials? Can you custom-tailor an organic material in such a way that, for certain excitation energies, excitons move in one direction, and when they confront obstacles, they can move around them?”Yuen-Zhou and Saikin began searching for molecules that fit a tightly defined set of criteria, and eventually settled on porphyrins, in part because they have been extensively studied.“These are just one example of a molecule that could work in this system,” said Saikin. “We don’t want to say that, experimentally, one has to do it with these molecules, but conceptually, we’ve shown that the electronic structure of these molecules is convenient for this system.”The system described in the paper, however, is about more than simply creating a film of porphyrin molecules.For the design to work, the team outlined how magnets could be used to prepare the molecules in specific quantum states to ensure they don’t interfere with one another.“In the absence of a magnetic field, it’s equally likely the excitons would go in one direction or another,” Aspuru-Guzik said. “We use some very clever quantum tricks, to ensure that, when we apply the field, one direction becomes more preferential.”Just as cars sitting in traffic on the highway are unable to turn around and drive in the opposite direction, Aspuru-Guzik said, excitons in this system are able to flow in only one direction, around the edges of the film.What’s more, Yuen-Zhou said, the quantum mechanics of the system permit a good deal of flexibility, allowing excitons to flow around defects in the material, just as a stream flows around obstructions.While it may be years before the material finds its way into commercial solar panels, Aspuru-Guzik believes it has the potential to increase their efficiency by creating a flow of excitons that moves along the panel’s interface, more efficiently transferring energy into electricity.“What we’ve done with this paper is a proof of concept, and we hope it’s the opening to a new era of excitonics.”last_img read more

Kluivert gives reason for Ghana snub

first_imgPatrick Kluivert has been explaining the reasons behind his sabbatical leave from football including why he snubbed the offer of coaching the Ghana national team.The former Ajax, Barcelona and Netherlands goal poacher was heralded as the favourite to replace dismissed Kwesi Appiah at the helm of the Black Stars after the Ghana Football Association named him on a shortlist of five for the job. But his agent came out to deny he had even applied for the job in the first place.Kluivert who was also linked to the Manchester United assistant manager’s role having played under Old Trafford manager, Louis Van Gaal at Ajax and Barcelona before also serving as his assistant with both Dutch club, AZ Alkmaar as well as the Dutch national team at the recent FIFA World Cup, says his wife’s ill-health was chief in his decision not to take on other jobs.The UEFA pro coaching licenced Kluivert says he combined his Netherlands duties during his three-year stint under van Gaal with caring for his wife, Rossana, who was diagnosed with lymphoma, a form of cancer that affects the immune system.”At that time I couldn’t have taken another job because of my wife’s illness,” he explained.”Now I’m ready to make a big jump for myself. I’m really looking for a club or a possibility in the near future to get a chance to lead training as a manager or work as an assistant to a very good coach,” Kluivert added. Having spent all his managerial apprenticeship under van Gaal, Kluivert says he was also not particularly keen on the Manchester United job because he knew Ryan Giggs would get the role and he also felt that it was time to move on from Van Gaal’s mentorship.”Louis said that he wanted the position of assistant coach to be someone from the club and that was reasonable. And it was also time to spread my wings and to do something on my own,” Kluivert said.”But working with Louis was great because he gives you the freedom to train the team and that’s the thing I appreciated,” he confessed.last_img read more

Neymar rape allegation: PSG player denies Paris hotel claims after Brazilian files report with police

first_img“Faced with the unfortunate, illegal and outrageous allegations, we completely repudiate the unfair accusations and, above all, the exposure in the press of an extremely negative situation.“All evidence of attempted extortion and non-rape shall be submitted to the police in a timely manner.”Neymar is currently in Brazil getting ready for the Copa America finals in June and July with the national team. Brazilian outlet UOL was the first to report the rape accusations and claim the report to police is being kept confidential.Neymar’s father suggested on Saturday night that the WhatsApp messages his son exchanged with the woman, whom was flown into Paris on May 15, would be published in an attempt to prove his innocence to the public.”I know that my son can be accused of many things, but I know the boy that he is, the man that he is, the son of a father and a mother,” Neymar Sr. said. “We will push for justice to be served as quickly as possible.” Reports in Brazil claim Neymar paid for her travel and met her at Sofitel Paris Arc de Triomphe. The 27-year-old says he met her at the hotel but contests the serious claims from the unnamed woman, who is protected by anonymity.”I’m being charged of rape,” Neymar said in an Instagram video published on Sunday morning that was viewed more than 10 million times before he deleted it. “It’s a heavy word, it’s a very strong thing, but it’s what’s happening right now.“I was taken by surprise. It was very bad, very sad to hear that. You know my character, you know what I mean, you know I would never do something like that.“But I’ve been exposed to it and I’m here to make a face of it, because I know that any news with my name involves a lot of things, it makes a very loud noise, and everybody keeps wanting my statement, and what happened was totally the opposite of what they say.“From now on I will expose everything, I will expose all the conversation I had with the girl, all our moments, which are intimate, but it is necessary to be open, it is necessary to expose to prove that nothing really happened at all.”Neymar shared conversations that claim the two began speaking in March and continue May 15. His messages allege that she invites the former Barcelona star back to the hotel on May 16.The woman reportedly returned to Sao Paulo on May 17 before taking her case to a police station that specialises in women’s defence on May 31. “What happened that day was a relationship between a man and a woman, within four walls,” the PSG player claimed. “Something happens with every couple, and the next day nothing happened.”We kept chatting, she asked me for a souvenir for her son, and I was going to take it, and well… now I am surprised by these claims.“It’s very bad, very sad. This not only hurts me, but like my whole family, because not only denigrating my image is bad, but what I am, who I am, the nature I have, the character I have.”An official statement released by Neymar’s PR team alleges the player was the victim of an extortion attempt before the allegations came to light on Saturday night.“Although he was surprised by the news, the facts were already known by the player and his staff, considering that a few days ago he was a victim of attempted extortion, practiced by a lawyer from the city of Sao Paulo, who, according to his version, represented the interests of the woman,” the statement said.“The athlete’s lawyers were immediately notified and have since taken all relevant steps. Paris Saint-Germain forward Neymar has vehemently denied a rape allegation being levelled at him to Sao Paulo police, following claims from a Brazilian woman he met in Paris. Police in Brazil confirmed to Goal on Saturday that there is a complaint against Neymar, but would not discuss details of the case, which was filed on May 31.last_img read more

HOSPITAL WORKER SUSPENDED AFTER CHILD ALLEGEDLY ASSAULTED

first_imgA staff member at Letterkenny General Hospital has been suspended following allegations that a child was physically assaulted.A full investigation has been launched at Letterkenny General Hospital.The alleged incident, which happened in recent days, has sparked a full investigation at the hospital.Health bosses have confirmed to Donegal Daily that an incident is being investigated but are refusing to divulge specific details of the incident. However it is understood a medic has been suspended after it was alleged that she struck a four year old child.It is understood the incident was witnessed by one of the child’s parents.The matter was then reported to hospital management who took immediate action against the medic.A spokesman for the hospital (part of the West/North Hospitals Group) confirmed it is investigating a “trust in care” incident. “Letterkenny General Hospital (part of the West/North West Hospitals Group) is investigating a “Trust in care” incident concerning a child who was attending the hospital, accompanied by its parent.“Letterkenny General Hospital is guided by two policies when dealing with such incidents.“The “Children First” policy states that the key principles informing best practice are that the welfare of children is of paramount importance and that all personnel and health professionals, irrespective of the position held within the organisation, have a responsibility towards child protection and welfare.”The spokesman said the “Trust in Care” policy aims to ensure any allegations or complaints against a member of staff are thoroughly investigated.This policy states that, “at an appropriate stage in the process, management should take whatever protective measures are necessary to ensure that no patient/client or staff member is exposed to unacceptable risk. “These protective measures are not disciplinary measures and may include putting the staff member off duty with pay pending the outcome of the investigation.”The spokesman added that in the interests of fairness and to ensure due process, the nature of any investigation is not discussed with third parties not associated with the alleged incident.A statement from the West/North West Hospitals Group said the matter may be referred to Gardai if appropriate.“When the results of the investigation are known, appropriate action is taken, up to and including disciplinary action and, where appropriate, the reporting of the incident to external authorities.” HOSPITAL WORKER SUSPENDED AFTER CHILD ALLEGEDLY ASSAULTED was last modified: November 5th, 2013 by StephenShare this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)Click to share on Telegram (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to share on Skype (Opens in new window)Click to print (Opens in new window)Tags:assaultinvestigationLetterkenny General Hospitallast_img read more