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By Admin (from 05/01/2012 @ 14:05:24, in it - Scienze e Societa, read 1178 times)

Doppio flash. Dunque un' esplosione nucleare. La prima interpretazione di quell'anomalo bagliore sotto la punta del Sudafrica, vicino alle isole del Principe Edoardo, fu la più drastica e anche la più ovvia. A rivelarlo, alle 3:00 ora locale del 22 settembre 1979, era stato il satellite Vela 6911, membro dell'omonima famiglia di una dozzina di esemplari lanciati nello Spazio a partire dal 1963 dal governo americano per rilevare eventuali test nucleari in terra o nell'atmosfera (il Partial Test Ban Treaty era infatti appena stato firmato). Da allora erano state già 41 le segnalazioni nel corso degli anni, tutte confermate, e l' incidente di Vela (come passerà alla storia l'evento del 1979) era sul punto di diventare il quarantaduesimo. Se non fosse che quella volta i conti decisamente non tornavano.

Il satellite Vela 5b rappresentato nello spazio.
Uno degli elementi della famiglia Vela lanciati dagli Stati Uniti per rivelare eventuali test nucleari (Credits: Los Alamos National Laboratory/NASA).

Primo: nessuna sostanziale registrazione sismica né segnali idro-acustici erano stati rinvenuti nell'area di quasi 5mila chilometri interessata dalla possibile esplosione (tranne un piccolo botto ascoltato da alcuni idrofoni nei fondali marini). Insomma la detonazione era data per scontata (e i colpevoli ricercati tra Israele e Sudafrica) ma non sembrava aver fatto rumore, né aver scosso la terra, secondo quanto riferiva il primo report ufficiale sull'accaduto del National Security Council. Secondo: i due bhangmeter montati su Vela 6911 (sensori ottici pensati per individuare i due flash caratteristici di un'esplosione nucleare) avevano sì registrato due eventi luminosi, ma in modo diverso l'uno dall'altro. Certo, si trattava di una strumentazione datata (il satellite era partito circa 10 anni prima, andando decisamente oltre l’iniziale aspettativa di vita di 18 mesi). Ma c'era anche un terzo punto che non collimava.

Gli uomini dell'intelligence americana spediti in quel luogo alla fine del mondo, per cercare una qualsiasi traccia di materiale radioattivo su piante e animali, tornarono a casa a mani vuote, o quasi (vennero rinvenute solo tracce di iodio 131 in alcune pecore australiane). Quarto, il gemello di 6911 (i satelliti Vela venivano lanciati in coppia) non aveva visto nulla. Quinto: anche la perturbazione nella ionosfera osservata dal radiotelescopio Arecibo quel giorno di settembre - uno dei punti che sembrava favorire l'ipotesi di una detonazione nucleare - benché anomala non indicava necessariamente un'esplosione, secondo gli esperti.

Questo, e la mancanza di colpevoli dichiarati, spinse gli Usa a rimettere mano al loro giudizio. Già nel 1980, infatti, la loro posizione era completamente cambiata: accanto all'ipotesi di un'esplosione nucleare si faceva largo l'idea che quel flash sull'Atlantico potesse essere stato solo un “falso allarme” (in pratica un malfunzionamento della strumentazione a bordo di Vela 6911) o un evento di “origine naturale”, come l'impatto di un meteorite sul satellite. Se infatti Vela 6911 fosse stato colpito, parte della sua strumentazione poteva essere stata compromessa, addirittura rotta e dispersa. E quei flash allora? Solo la luce del sole riflessa come in uno specchio da alcuni detriti spaziali. Oppure un'esplosione, sì, ma del meteorite spaccato in due.

Fonte: daily.wired.it

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On January 1st, 2012 sometime between 1:00 am
and 1:30 am, I was driving my friend home from
a New Years Eve party. I was the designated
driver and was sober. We pulled into the 7-11 on
Lamar & West 10th in Austin TX to get gas, and
we saw ourselves near a car that was pulled over
with two police cruisers behind it. A black woman
was being given a field sobriety test in the cold.
She seemed to be getting bossed around by the
cops, and we both took notice. They had her doing
the heel to toe test in high heels. In the passenger
seat was a young Hispanic lady who appeared to
be on her phone.
She was doing nothing aggressive.

As we finished pumping gas, a cop had gone over
to the passenger side door and opened it.
Soon after we heard a terrible scream and watched
in horror as the very built cop started yanking this
poor girl from the car. The other cop came up
and joined in on the abuse.

My friend and I stayed within two arms lengths of
the truck, and tried to take pictures and yelled at the
cops to stop assaulting the girl.

After that, one cop came up to me yelling at me and
asking why I was taking pictures. I said it was my
right in public, and he pushed me into the truck and
started yelling in my face. I asked him why he
pushed me, I put up my arms to show I wasn't a
threat, told him to get out of my face, and that I had
done nothing illegal. He then grabbed my arm, and
pinned me against the truck, at which time
he claimed I "spit" on him.

They arrested me, claimed it was for "interfering
with an investigation". By the time I got to their
truck, it was a DUI and they made me blow. It didn't
register, and by the time I got to jail it was then a
"felony harassment" and a "resisting arrest" charge.

The woman was arrested for "public intoxication".
The cops said that she was interfering with their DUI
investigation because she yelled to her friend not to
submit to any tests. Interestingly, neither of us was
charged with interfering in an investigation.

Statement from Antonio Buehler.

Who is Antonio F. Buehler? – Managing Director

Antonio is the Founder and Managing Director of Trophy Point Capital. Antonio is a proven leader who has overcome many obstacles to lead various organizations to new levels of excellence.

Raised in a single-parent household in an Eastern Pennsylvania coal mining town, Antonio Buehler was the first in his family to graduate from high school. He attended the United States Military Academy at West Point, and then, as a U.S. Army officer, Antonio completed six months of Airborne Ranger training where he honed the leadership skills and discipline that he had developed at West Point. In his first operational unit, he led the turnaround of two underperforming 27-soldier platoons in Kosovo and Germany. Antonio subsequently turned around the administration and logistics of a 67-soldier company, and executed the movement of thousands of U.S. soldiers from Europe and the United States to Iraq. Then, in a position normally reserved for senior officers with much more experience, Antonio solved critical supply shortages for the U.S. Army in the early days of the Iraq war. These tasks involved dealing with numerous American military units, foreign militaries, civilian contractors from half a dozen nations, and Shia, Sunni and Kurdish Iraqis. Antonio was commended for his actions and awarded a Bronze Star.

After the military Antonio received his MBA from the Stanford Graduate School of Business, where he interned as a private equity professional, technology consultant, and investment management consultant. After business school he worked as an investment banking Associate in the Financial Restructuring Group of Houlihan Lokey Howard & Zukin, where he advised two distressed middle-market companies. Antonio conducted due diligence and performed financial analyses to determine various strategic options available to the companies, including financings, restructurings, and sales to financial or strategic buyers. Antonio raised over $260 million in financing and redeemed $240 million in debt.

Antonio’s philanthropic activities focus on helping disadvantaged youth. He is a board member of A Caring Hand, a New York based non-profit focused on child bereavement. He also ran a program to clothe children in war-torn Kosovo, volunteered at a Bulgarian orphanage, coached high school football in Germany, mentored children in the United States, and sponsors three African children through Plan USA. Antonio covers Congressional Districts NY-8 and NY-9 as a Field Force Representative for the West Point Department of Admissions. He also serves on the Board of Governors for the West Point Society of New York.

Source: http://trophypointcapital.com

Who We Are

Trophy Point Capital is a private investment firm established specifically to make long-term majority investments in privately held middle-market education companies. Trophy Point Capital is backed by a world class team of investors and advisors who collectively have decades of experience investing in, operating and growing hundreds of companies. This team includes successful executives of businesses ranging from start-ups to Fortune 20 companies, entrepreneurs, and private equity investment professionals.

What We Do

We invest in highly profitable education companies that are well-positioned for continued success. We take an active management role in the companies in which we invest, which allows us to provide attractive alternatives for entrepreneurs who are seeking to transition out of their business while ensuring the successful continuation of their legacy. It also positions us to be the ideal equity partner for owners who realize that additional management and a professional, active board can take the company to the next level. Additionally, unlike other private equity firms, we do not have defined holding periods for our investments, and our bias is to compound our principal, not quickly “flip” a company. Our team is focused on building long-term sustainable companies that create significant value for their community, employees, and shareholders.

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Autorii studiului, cercetatorii de la Colegiul Universitar din Londra, au mai descoperit si ca fluctuatiile IQ-ului corespund cu unele mici schimbari fizice ale unor arii din creier, asociate cu o serie de activitati intelectuale. Totusi, studiul nu a putut sa arate clar care sunt cauzele si efectele acestui fenomen.

Coeficientul de inteligenţă al adolescenţilor se poate schimba considerabil în câţiva ani

Specialistii anunta ca daca aceasta constatare este adevarata, atunci ea semnaleaza ca factorii de mediu au capacitatea de a schimba creierul si implicit inteligenta, într-o perioada realativ scurta.
Pentru a întelege mai bine inteligenta, cercetatorii au studiat 33 de adolescenti britanici ai caror IQ a variat de la 80 la 140 de puncte. Subiectii au fost examinati odata în 2004, cu ajutorul unor teste standardizate de masurarea inteligentei si apoi în 2008, folosind tehnici de imagistica prin rezonanta magnetica.

Analizând separat nivelul de inteligenta verbala si nonverbala, specialistii au constatat ca aspectele fundamentale ale inteligentei se pot schimba semnificativ chiar si atunci când, în ansamblu, scorul IQ ramâne relativ constant.

O cincime dintre subiectii studiului au înregistrat fluctuatii. IQ-ul verbal al unui adolescent a crescut de la 120, la vârsta de 13 ani, la 138, când a împlinit 17 ani, în timp ce IQ-ul nonverbal a scazut sub medie, de la 103 la 85.

Fluctuatiile nivelului de inteligenta verbala par sa fie legate de o arie din creier responsabila cu vorbirea, pe când cele ale inteligentei nonverbale sunt asociate cu o parte a creierului implicata în controlul motor.

În ultimii ani, oamenii de stiinta au ajuns la concluzia ca experientele de viata, activitatea de zi cu zi pot determina modificari la nivelul creierului, pe masura ce retelele sinapselor neuronale se dezvolta ca raspuns al activitatii sau se atrofiaza în lipsa utilizarii.

Mai multi neurologi considera ca modificarile de la nivelul creierului ar putea reflecta ritmul normal de crestere si ca schimbarile invocate de autorii studiului se datoreaza inconstantei testelor.
Alti experti, însa, au fost încrezatori în rezultatele studiului, sustinând ca variatiile inteligentei ar fi fost dovezi ale impactului neuronal pe care îl are experienta.

Sursa: The Wall Street Journal

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Calendario 2012: ecco i giorni festivi in cui non si lavora.

Fa eccezione il primo dell’anno, che è capitato di domenica. Si inizia con la Befana, l’Epifania: venerdì 6 gennaio. Poi niente feste fino a Pasqua e Pasquetta: 8 e 9 aprile. Il 25 aprile, la festa della Liberazione, quest’anno è di mercoledì. Il primo maggio è di martedì. La festa della Repubblica del 2 giugno è di sabato: salta il “ponte”. Ferragosto, il 15 agosto, cade di mercoledì. Il 1 novembre, giorno di Ognissanti o Tutti i Santi, è di giovedì. L’Immacolata, l’8 dicembre, è di sabato. Natale e Santo Stefano, 25 e 26 dicembre, cadono di martedì e mercoledì. Il primo dell’anno del 2013 sarà di martedì.

L’ora legale entrerà in vigore nella notte fra sabato 24 e domenica 25 marzo. L’ora solare nella notte fra sabato 27 e domenica 28 ottobre.

Fra le ricorrenze che non si traducono in ferie, San Valentino, il 14 febbraio, è un martedì. Due giorni dopo, il 16 febbraio, è giovedì grasso. Domenica 19 febbraio è Carnevale, il 21 febbraio è martedì grasso. La festa di San Giuseppe, o “del papà”, è lunedì 19 marzo. Occhio agli scherzi durante la domenica delle Palme: è il 1° aprile. La festa della mamma è domenica 13 maggio. La Pentecoste domenica 27 maggio. Il 2 novembre, giorno dei Morti, è un venerdì. San Silvestro, il 31 dicembre, un lunedì.

Feste patronali: per i romani, SS. Pietro e Paolo sarà venerdì 29 giugno. I milanesi festeggeranno Sant’Ambrogio venerdì 7 dicembre. Bologna: San Petronio è giovedì 4 ottobre. Torino e Genova: San Giovanni Battista è domenica 24 giugno. Napoli: San Gennaro è mercoledì 19 settembre. Palermo: Santa Rosalia cade di domenica, 15 luglio.

Ecco uno schema riassuntivo dei giorni festivi e delle ricorrenze del 2012, preso dal sito Calendario-365.it.

Fonte: www.blitzquotidiano.it

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New research by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington shows that innovative and improved methods for analyzing verbal autopsies – a method of determining individuals' causes of death in countries without a complete vital registration system – are fast, effective, and inexpensive, and could be invaluable for countries struggling to understand disease trends.

While many high-income countries such as the United States, Canada, and Australia have death certification systems, many countries cannot afford these systems, which means causes of death are not officially recorded. As a result, these countries lack critical information about why people are dying and which risk factors contribute to those deaths, as they attempt to track and address health challenges.

Verbal autopsy (VA) consists of a trained interviewer using a questionnaire to collect information about the signs, symptoms, and demographic characteristics of a recently deceased person from an individual who knew them. Methods used to analyze interviews and assign a cause of death include physician certification, whereby physicians review each questionnaire to assign a cause, and new automated methods where the VA interview is conducted on a hand-held device and a cause of death is automatically generated at the end of the interview. Until now, there has been no clear evidence as to how accurate the methods were, and some methods such as the physician review were costly and time consuming.

A new collection of research published in the Population Health Metrics thematic series, Verbal autopsy: innovations, applications, opportunities, provides the most up-to-date research in the field, including the use of a new automated tool to do the analysis instantaneously at the completion of the interview. Yielding fast and affordable results, this new automated method outperforms any other method to date.

"Accountability is becoming increasingly important to both governments and funders as they try to allocate resources and measure success," said Dr. Christopher Murray, Director of IHME and Professor of Global Health at the University of Washington. "With the new innovative methods outlined in our research, countries can now choose the best and most cost-effective verbal autopsy techniques to better monitor progress toward health and development goals."

The Random Forest method, developed by IHME, performed better than physician review, which traditionally has been seen as the gold standard, and is also cheaper and provides faster results.

The Random Forest method was more accurate than physicians in assigning the correct cause of death to individual VAs for adults and children older than 28 days. For VAs on adults, the Random Forest method performed 27% better than physicians when there is no accompanying medical information from those interviewed. In cases where there is additional information, the Random Forest method was better by 8%. For VAs on children older than 28 days, the Random Forest method performed 28% better than physicians with no additional medical information and 8% better for VAs including other information.

"While it may take days for a team of physicians to complete a VA survey analysis, requiring them to stop servicing health needs in a population, a computer approach such as the Random Forest method requires only seconds of processing on hardware that is currently affordably available," said Dr. Abraham Flaxman, lead author of the Random Forest study and Assistant Professor of Global Health at IHME. The Random Forest method can be used on a hand-held device with the cause of death automatically generated at the conclusion of the interview.

"Understanding causes of deaths is a public health priority especially in low-resource settings such as Uganda where most deaths occur at home and no regular system for cause of death registration exists," said Dr. Peter Waiswa of the Department of Health Policy, Planning and Management at Makerere University School of Public Health in Uganda. "We have wanted to use verbal autopsy to bridge that gap. However, available methods are cumbersome, data collection is time consuming, and coding by physicians is not always done correctly, or there is no physician available, so these new automated methods are a real breakthrough."

"This is a major discovery and we are excited about the possibilities," said Dr. Palitha Mahipala, Additional Secretary, Medical Services at Sri Lanka's Ministry of Health. "Nothing can replace a complete and efficient vital registration system. But as countries work to implement or improve those systems, the new methods in verbal autopsy are ready now, at low cost, and with rapid results. This allows us to better understand cause of death trends and to measure program performance."

"Even in countries with vital registration systems, this is a tremendous benefit," said Jarbas Barbosa da Silva Jr., Secretary of Health Surveillance at Brazil's Ministry of Health. "This is a way to validate whether your death certification system is accurately classifying deaths."

The research published in the Population Health Metrics thematic series emerged from the Global Congress on Verbal Autopsy: State of the Science, held in Bali, Indonesia, in February 2011. The conference was co-sponsored by IHME, the University of Queensland School of Population Health, and Population Health Metrics to discuss important aspects of instrument design, analysis methods, and the use of verbal autopsy in national health information systems, with the goal being to take VA methods from infancy to maturity, so that countries that needed them could start using them right away.

"This body of work is by far the biggest breakthrough in years in this field," said Alan Lopez, one of the Editors-in-Chief of Population Health Metrics. "For the first time, countries will be able to measure with confidence whether people are dying from HIV/AIDS, maternal causes, or from largely preventable noncommunicable diseases, which gained the world's attention at the recent United Nations meeting."

As part of this work, IHME researchers developed standardized metrics to compare the performance of all types of VA methods to help identify the best ways to estimate causes of death in a population. IHME researchers also helped to create the first strictly defined gold standard database of diagnoses for causes of death to test VA methods, validated over five years in four countries with large populations, including India, Mexico, the Philippines, and Tanzania.

Source: EurekAlert

The Institute for Health Metrics and Evaluation (IHME) is an independent global health research center at the University of Washington that provides rigorous and comparable measurement of the world's most important health problems and evaluates the strategies used to address them. IHME makes this information freely available so that policymakers have the evidence they need to make informed decisions about how to allocate resources to best improve population health. For more information, please visit http://www.healthmetricsandevaluation.org

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The Zeitgeist Movement is a global sustainability activist group working to bring the world together for the common goal of species sustainability before it is too late. It is a social movement, not a political one, with over 1100 chapters across nearly all countries. Divisive notions such as nations, governments, races, political parties, religions, creeds or class are non-operational distinctions in the view of The Movement. Rather, we recognize the world as one system and the human species as a singular unit, sharing a common habitat. Our overarching intent could be summarized as 'the application of the scientific method for social concern.

Jan. 4th 2012

Listen to internet radio with TZM Global Radio on Blog Talk Radio

Jim Phillips, Liam Swords (Lee Hamster) and Simon Andrew from Action on Education

About : Started in 2009, TZM Global Radio is a weekly radio show presented by various coordinators/lecturers of The Zeitgeist Movement in a rotational fashion.

Free Show Archives: http://www.thezeitgeistmovement.com/radio_shows

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By Admin (from 04/01/2012 @ 14:06:29, in it - Osservatorio Globale, read 772 times)

Il Premio Nobel per la fisica 2011 è stato assegnato appena a chi ha dato il suo contributo per scoprire quale sia il futuro dell'Universo (leggi Galileo “Un Nobel per la fisica che apre le porte all'energia oscura”). Ma oggi, grazie a una simulazione eseguita con un supercomputer, conosciamo meglio anche il suo passato e il suo presente: si chiama Bolshoi Simulation e rappresenta il più grande e dettagliato modello cosmologico dell'evoluzione dell’Universo mai realizzato.

Questo strumento, descritto in uno studio in via di pubblicazione sulla rivista Astrophysical Journal (e già reperibile online su arXiv), potrà essere utile per la comprensione di “misteri” come la formazione di galassie o la genesi di materia ed energia oscure. Gli autori dello studio sono ricercatori dell'Università della California di Santa Cruz e della Nasa, che hanno anche pubblicato un esempio di simulazione in un video su Vimeo (in particolare relativa alla materia oscura presente al centro di un grande ammasso di galassie) e numerose immagini ricavate attraverso di essa.

Il Bolshoi si basa su dati raccolti negli scorsi anni da osservazioni condotte sia da terra sia dalla missione Wilkinson Microwave Anisotropy Probe (Wmap) della Nasa; quest’ultima ha fornito una mappa precisa delle leggere variazioni che si rilevano nella misura della radiazione cosmica di fondo, ovvero la radiazione termica primordiale che è considerata essere l'ultima eco del Big Bang.

Precedentemente erano già state effettuate ricostruzioni della struttura e dell'evoluzione dell'Universo con l'uso di supercomputer: l'ultima, la Millennium Run, è stata la base di circa 400 diversi articoli dal 2005 ad oggi. Ma la Bolshoi Simulation la supera sia in risoluzione che in accuratezza: da quando la simulazione precedente è stata sviluppata ci sono stati avanzamenti significativi nella velocità dei supercomputer, ma soprattutto è migliorata la misurazione dei parametri cosmologici che sono alla base dell'elaborazione. I dati su cui questa si basava erano, infatti, i primi rilasciati dalla missione Wmap, che sono stati superati da quelli ottenuti nel 2008 (Wmap5, ovvero i risultati di cinque anni di osservazioni) e nel 2010 (Wmap7, a sette anni dall'entrata in funzione del satellite Nasa).

La nuova simulazione è invece basata proprio sui parametri Wmap5 (che sono comunque in linea con gli ultimi rilasciati dalla Nasa) e, secondo i ricercatori che hanno lavorato al modello, diventerà il punto di riferimento per tutti gli studiosi di cosmologia che vorranno testare le loro previsioni teoriche. “Oggi sappiamo che i dati ricavati da Wmap1 sono inesatti - ha spiegato Joel Primack, tra i realizzatori del Bolshoi - e mi aspetto che lo strumento abbia un forte impatto nel campo dell'astrofisica”.

Così, come si analizza una popolazione intera studiandone un campione rappresentativo, il Bolshoi ha nello specifico ricostruito l'evoluzione solo di un volume dello Spazio: un cubo di un miliardo di anni luce di lato, porzione ridotta dell'Universo visibile (che ha la forma di una sfera con un raggio pari a 46 miliardi di anni luce). Attraverso di esso, la simulazione non mostra solo in che modo sia cambiato ciò che riusciamo a vedere, ma anche quello che ci è invisibile: ecco perché, secondo gli astronomi, lo strumento potrà predire l'evoluzione degli aloni di materia oscura, per poi facilitarne la ricerca nel Cosmo.

“In un certo senso si può quasi pensare che i primi risultati siano piuttosto noiosi, perché mostrano solo che il nostro modello cosmologico standard funziona - ha aggiunto Primack -  ma veramente eccitante è che ora possediamo una simulazione talmente accurata che può essere la base di innumerevoli nuovi studi”.

Riferimento: Bolshoi Simulation

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Cercetatorii de la Universitatea de Medicina din Pennsylvania au identificat 1.105 copii nascuti între 1 octombrie 1984 si 3 iulie 1989 si care în momentul nasterii cântareau mai putin de 2 kilograme.

Dupa 16 ani, specialistii au reusit sa îi gaseasca pe 623 dintre copii si i-au testat cu ajutorul unui set de întrebari pentru depistarea unor tulburari din spectrul autismului.

Copiii cu greutate mică la naştere prezintă un risc mai mare de a suferi de autism

Când 189 dintre acesti tineri au împlinit 21 de ani, ei au fost supusi unor noi teste, iar 60% dintre cei care fusesera initial diagnosticati cu o forma de autism, dar si 24% dintre cei care nu fusesera diagnosticati, au fost identificati ca având tulburari din spectrul autismului.
În final, incidenta tulburarilor din spectrul autismului a participantilor la studiu a fost de cinci ori mai mare decât a populatiei gerenale.

Tulburarile din spectrul autismului îi fac pe oameni sa aiba dificultati în comunicare si în interactiunile sociale, sustine unul dintre autorii studiului, Jennifer Pinto-Martin. Totusi, persoanele care au forme mai usoare de tulburari din spectrul autismului sunt perfect functionale, putând sa mearga la o facultate si sa aiba o slujba. Singura problema este ca ele s-ar putea sa doreasca sa vorbeasca doar despre un anumit subiect.

Desi studiul demonstreaza ca tulburarile din spectrul autismului apar mai des la copiii nascuti prematuri, care vin pe lume cu o greutate mai mica, specialistii spun ca autismul este în continuare întâlnit si la copiii nascuti la termen.
Studiul sugereaza ca este nevoie de un sistem de îngrijire prenatala mai bun pentru a reduce numarul nasterilor premature, dar si de o diagnosticare precoce a cazurilor de autism.

Sursa: Xinhuanet - via descopera.ro

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Experts in gravitational waves from the School of Physics and Astronomy have secured almost 16.7 million hours worth of supercomputer time to simulate and map the most violent events in the universe since the big bang – namely, collisions of black holes.

The team will use more than 1,900 computer processors over the next year to try and solve the equations of Einstein’s general theory of relativity.

The ultimate goal of the simulations is the direct observation of black-hole collisions through the gravitational waves they emit.

"Gravitational waves are ripples in space and time – predicted by Einstein almost 100 years ago," according to Mark Hannam, School of Physics and Astronomy, who will lead the Cardiff research team.

"However, despite Einstein’s predictions – they have not yet been directly detected. Gravitational waves are generated by accelerating masses, such as orbiting black holes, similar to the way accelerating electrical charges emit electromagnetic waves, like light, infra-red and radio waves - with the important difference that gravitational waves are far weaker.

"For this reason it is electromagnetic waves that have told us everything we have learnt about the cosmos since ancient times. If we could also detect gravitational waves, that would push open a new window on the universe, and tell us about its `dark side'," he added.

Over the past decade a network of gravitational wave detectors has been built, including the US Laser Interferometer Gravitational-Wave Observatory (LIGO) and the European GEO600 and Virgo detectors, with the ambitious goal of not only making the first direct detection of the gravitational waves, but also to observe the entire Universe through gravitational radiation.

Cardiff's researchers work on theoretical modelling of black-hole-binary collisions using state-of-the-art numerical techniques and high performance computer clusters, strong field tests of gravity with gravitational-wave observations and the development of algorithms and software to search for gravitational waves.

Researchers at Cardiff play leading roles within the LIGO Scientific Collaboration, in particular in gravitational-wave searches for compact binary coalescences, supernovae, gamma-ray bursts, and other transient sources.

Coalescing black holes are prime candidates for the first observations. The results of this project will help to identify the sources of these signals, and contribute to answering important open questions in astrophysics and fundamental physics, such as whether the objects created in these cosmic collisions are really black holes, or even more exotic objects like naked singularities.

In the process the team hope to be able to test if Einstein's theory of gravity is correct, or whether, just as Newton's gravity gave way to Einstein's, perhaps Einstein's relativity gives way to even deeper insights into the nature of space and time.

The research team comprises more than 20 physicists working at Cardiff, the Universities of Jena, Vienna, and the Balearic Islands, the Albert Einstein Institute in Potsdam, and the California Institute of Technology. Solving Einstein's equations on supercomputers to accurately describe black holes became possible only after a series of breakthroughs in 2005, and the mostly young researchers are excited to be part of a scientific revolution.

"The detectors are pushing against the limits of current technology, and now we will help them with simulations that are at the cutting edge of computing power. Access to such vast computing resources is a fantastic boost for scientific research in Wales," Dr. Hannam added.

While supercomputing resources in Europe used to be relatively scarce, the PRACE Research Infrastructure now provides access to world-class supercomputers for European research projects, which undergo a competitive peer review process.

The PRACE infrastructure currently consists of three world-class supercomputers, which can each perform about 1 Petaflop which is a thousand billion arithmetic operations per second. The first machine in the network, the German Jugene, started operation in 2010, and it was joined in early 2011 by the French machine Curie, and the German system Hermit is about to officially start operation on November 1.

Future computers in the PRACE network are planned in Germany, Italy, and Spain.

Source: Cardiff University

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They could lead to "superlenses" able to image proteins, viruses and DNA, and perhaps even make a "Star Trek" cloaking device.

Other metamaterials offer unique magnetic properties that could have applications in microelectronics or data storage.

The limitation, so far, is that techniques like electron-beam lithography or atomic sputtering can only create these materials in thin layers. Now Cornell researchers propose an approach from chemistry to self-assemble metamaterials in three dimensions.

Two polymer molecules linked together will self-assemble into a complex shape, in this case a convoluted "gyroid." One of the polymers is chemically removed, leaving a mold that can be filled with metal. Finally the other polymer is removed, leaving a metal gyroid with features measured in nanometers. Credit: Wiesner Lab

Uli Wiesner, the Spencer T. Olin Professor of Engineering, and colleagues present their idea in the online edition of the journal Angewandte Chemie.

Wiesner's research group offers a method they have pioneered in other fields, using block copolymers to self-assemble 3-D structures with nanoscale features.

A polymer is made up of molecules that chain together to form a solid or semisolid material. A block copolymer is made by joining two polymer molecules at the ends so that when each end chains up with others like itself, the two solids form an interconnected pattern of repeating geometric shapes -- planes, spheres, cylinders or a twisty network called a gyroid. Elements of the repeating pattern can be as small as a few nanometers across. Sometimes tri-polymers can be used to create even more complex shapes.

After the structure has formed, one of the two polymers can be dissolved away, leaving a 3-D mold that can be filled with a metal -- often gold or silver. Then the second polymer is burned away, leaving a porous metal structure.

In their paper the researchers propose to create metal gyroids that allow light to pass through, but are made up of nanoscale features that interact with light, just as the atoms in glass or plastic do. In this way, they say, it should be possible to design materials with a negative index of refraction, that is, materials that bend light in the opposite direction than in an ordinary transparent material.

Special lenses made of such a material could image objects smaller than the wavelength of visible light, including proteins, viruses and DNA. Some experimenters have made such superlenses, but so far none that work in the visible light range. Negative refraction materials might also be configured to bend light around an object -- at least a small one -- and make it invisible.

The Cornell researchers created computer simulations of several different metal gyroids that could be made by copolymer self-assembly, then calculated how light would behave when passing through these materials. They concluded that such materials could have a negative refractive index in the visible and near-infrared range. They noted that the amount of refraction could be controlled by adjusting the size of the repeating features of the metamaterial, which can be done by modifying the chemistry used in self-assembly.

They tried their calculations assuming the metal structures might be made of gold, silver or aluminum, and found that only silver produced satisfactory results.

Could these materials actually be made? According to graduate student Kahyun Hur, lead author on the paper, "We're working on it."

Source: Cornell University

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