Pacientul, Atilla Kavdir, si-a pierdut trei dintre cele patru membre la vârsta de 11 ani, când, încercând sa goneasca niste pasari, a lovit liniile electrice cu o vergea metalica si a fost electrocutat.
Pe 21 ianuarie 2012, doua brate si un picior au fost prelevate de la un donator, fiind ulterior transplantate, în cursul unei interventii care a durat 12 ore. Ulterior, au aparut totusi complicatii care au facut necesara îndepartarea piciorului transplantat, la doar o zi dupa atasarea acestuia.
De la acelasi donator a fost prelevata fata, care a fost transplantata unui alt pacient, un tânar în vârsta de 19 ani, desfigurat în urma arsurilor capatate într-un incendiu, când era foarte mic. Este primul transplant de fata realizat în Turcia; operatia a durat noua ore.
Operatiile au avut loc la Spitalul Universitar Akdeniz, din regiunea Antalya din sudul Turciei.
By combining a gold alloy with boron carbide, an extremely hard ceramic that’s used in bulletproof vests, a team of EPFL researchers has succeeded in making the world’s toughest 18-karat gold (75% gold). With a Vickers hardness number of 1000, it’s harder than most tempered steels (600 Vickers) and thus almost impossible to scratch, except with a diamond. This discovery is the result of a three-year collaboration between the Mechanical Metallurgy Laboratory in EPFL’s Institute of Materials, under the leadership of Professor Andreas Mortensen, and the Swiss watchmaking company Hublot.
The process for developing this material is relatively complicated. Powdered boron carbide is heated to almost 2000°C, where it forms a rigid, porous structure by a process called sintering. A liquid molten alloy of gold is infiltrated under very high pressure into the pores of this structure, and then solidified, yielding a pore-free composite material. The final material is thus made up of two kinds of crystals that are intimately interconnected in space, like two three-dimensional labyrinths. Because the molten gold used is a previously-made alloy based on 24-karat gold and aluminum (3%) for strength, the final gold is thus 3% aluminum, 75% gold and 22% boron carbide.
By definition, gold is very soft. Managing to harden it to this degree while still maintaining 18-karat purity was a real challenge for the EPFL scientists. They overcame the obstacle by taking the ceramic-metal composite approach. Composite materials are created by artificially combining several materials that conserve their individual characteristics even after they’re assembled. In this they are different from alloys, in which atoms mix together to form a new, homogeneous, material.
The EPFL researchers aren’t the first to play around with different materials in an effort to make more resistant gold. They are, however, the first to have attained this degree of hardness in 18-karat gold. The first watches made using this new gold will be presented in 2012 at BaselWorld, the world watch and jewelry show.
The gross domestic product of the United States -- that oft-cited measure of economic health -- has been ticking upward for the last two years.
But what would you see if you could see a graph of gross domestic happiness?
A team of scientists from the University of Vermont have made such a graph -- and the trend is down.
Reporting in the Dec. 7 issue of the journal PLoS ONE, the team writes, "After a gradual upward trend that ran from January to April, 2009, the overall time series has shown a gradual downward trend, accelerating somewhat over the first half of 2011."
A graph of average happiness measured over a three year period running from Sept. 9, 2008 to Aug. 31, 2011, created by scientists at the University of Vermont using data from Twitter. Published in the journal PLoS ONE, Dec. 7, 2011. A regular weekly cycle is clear with the red and blue of Saturday and Sunday typically the high points -- and an overall downward trend in 2010 and 2011 is clear. Credit: Peter Dodds et al
"It appears that happiness is going down," said Peter Dodds, an applied mathematician at UVM and the lead author on the new study.
How does he know this? From Twitter. For three years, he and his colleagues gathered more than 46 billion words written in Twitter tweets by 63 million Twitter users around the globe.
In these billions of words is not a view of any individual's state of mind. Instead, like billions of moving atoms add up to the overall temperature of a room, billions of words used to express what people are feeling resolve into a view of the relative mood of large groups.
These billions of words contain everything from "the" to "pancakes" to "suicide." To get a sense of the emotional gist of various words, the researchers used a service from Amazon called Mechanical Turk. On this website, they paid a group of volunteers to rate, from one to nine, their sense of the "happiness" -- the emotional temperature -- of the ten thousand most common words in English. Averaging their scores, the volunteers rated, for example, "laughter" at 8.50, "food" 7.44, "truck" 5.48, "greed" 3.06 and "terrorist" 1.30.
The Vermont team then took these scores and applied them to the huge pool of words they collected from Twitter. Because these tweets each have a date and time, and, sometimes, other demographic information -- like location -- they show changing patterns of word use that provide insights into the way groups of people are feeling.
The new approach lets the researchers measure happiness at different scales of time and geography -- whether global patterns over a workweek -- or on Christmas.
And stretched out over the last three years, these patterns of word use show a drop in average happiness.
Or at least at drop in happiness for those who use Twitter. "It does skew toward younger people and people with smartphones and so on -- but Twitter is nearly universal now," Dodds said, "Every demographic is represented."
"Twitter is a signal," Dodds said, "just like looking at the words in the New York Times or Google Books." (Word sources that the team is also exploring in related studies). "They're all a sample," he says. "And indeed everything we say or write is a distortion of what goes on inside our head."
But -- like GDP is a distortion of the hugely complex interactions that make up the economy and yet is still useful -- the new approach by the UVM team provides a powerful sense of the rising and falling pulse of human feelings.
"Individual happiness is a fundamental societal metric," the researchers write in their study. Indeed the ultimate goal of much public policy is to improve and protect happiness. But measuring happiness has been exceedingly difficult by traditional means, like self-reporting in social science surveys. Some of the problems with this approach are that people often don't tell the truth in surveys and the sample sizes are small.
And so efforts to measure happiness have been "overshadowed by more readily quantifiable economic indicators such as gross domestic product," the study notes.
The new approach lets the UVM researchers almost instantaneously look over the "collective shoulder of society," Dodds says. "We get a sense of the aggregate expressions of millions of people," says Dodds's colleague Chris Danforth, a mathematician and a co-author the study, while they are communicating in a "more natural way," he says. And this opens the possibility of taking regular measures of happiness in near real-time -- measurements that could have applications in public policy, marketing and other fields.
The study describes hundreds of insights from the Twitter data, like a clear weekly happiness signal "with the peak generally occurring over the weekend, and the nadir on Monday and Tuesday," they write. And over each day happiness seems to drop from morning to night. "It's part of the general unraveling of the mind that happens over the course of the day," said Dodds.
In the long-term graph that shows an overall drop in happiness, various ups and downs are clearly visible. While the strongest up-trending days are annual holidays like Christmas and Valentine's Day, "all the most negative days are shocks from outside people's routines," Dodds say. Clear drops can be seen with the spread of swine flu, announcement of the U.S. economic bailout, the tsunami in Japan and even the death of actor Patrick Swayze.
"In measuring happiness, we construct a tunable, real-time, remote sensing, and non-invasive, text-based hedonometer," the Vermont scientists write. In other words, a happiness sensor.
Right now the sensor is only available to the researchers, but Dodds, Danforth and their colleagues have in mind a tool that could go "on the dashboard" of policy makers, Dodds says. Or, perhaps, on a real estate website for people exploring communities into which they might move, or, simply, "if someone is flying in a plane they could look at this dashboard and see how the city below them is feeling," he says.
Of course feelings change quickly and the nature of happiness itself is one of the most complex, profound issues of human experience.
"There is an important psychological distinction between an individual's current, experiential happiness and their longer term, reflective evaluation of their life," the scientists write, "and in using Twitter, our approach is tuned to the former kind."
And looking ahead, the Vermont scientists hope that by following the written expressions of individual Twitter users over long time periods, they'll be able to infer details of happiness dynamics "such as individual stability, social correlation and contagion and connections to well-being and health."
Dodds and his colleagues are no strangers to the debates over the role of happiness that can be traced back through Brave New World to Jeremy Bentham, Thomas Aquinas, and Aristotle. "By measuring happiness, we're not saying that maximizing happiness is the goal of society," Dodds says. "It might well be that we need to have some persistent degree of grumpiness for cultures to flourish."
Nevertheless, this study provides a new view on a compelling question: why does happiness seem to be declining?
Non sarà certo questa la scoperta che ci permetterà di leggere i pensieri degli altri esseri umani, ma di sicuro è un grande passo in avanti verso la comprensione del linguaggio. Il merito va al team di ricerca guidato da Brian Pasley,neurologo dell' Helen Wills Neuroscience Institute di Berkeley, che ha decodificato alcuni stimoli cerebrali alla base dell'ascolto. In questo modo, un giorno forse sarà possibile riprodurre in modo artificiale le parole percepite nella testa delle persone.
Tuttavia, come spiega Scientific American, questo non significa che saremo in grado di leggere anche i pensieri elaborati dal cervello stesso. Per l'esattezza, lo studio pubblicato su PLoS Biology dall'equipe di Pasley riguarda un algoritmo capace di tradurre in suoni gli stimoli cerebrali innescati dalle parole percepite da 15 volontari. Il test prevedeva di sottoporli all'ascolto di brevi parole – a volte inventate – come “ jazz”, “ cause” e “ fook” e vedere quali parti del loro cervello si attivassero.
Per registrare l'attività cerebrale, Pasley ha sfruttato elettrodi connessi direttamente alla superficie della corteccia uditiva. Si tratta di una procedura molto sofisticata resa possibile dal fatto che tutti i partecipanti dovevano comunque sottoporsi a interventi neurochirurgici per il trattamento di epilessia o tumori. Ogni volta che un volontario percepiva una parola, il computer registrava i segnali percepiti dal cervello e li elaborava nel tentativo di convertirli in un suono simile.
Ebbene, dai ripetuti esperimenti è emerso che esistono zone cerebrali deputate all'ascolto esclusivo di alcune frequenze sonore. Una sorta di mosaico neurale sensibile a uno spettro sonoro che va da 200 a 7.000 Hertz. Inoltre, sembra che per adesso l'algoritmo del team di Pasley sia in grado di riprodurre con più facilità suoni vocalici molto semplici. Così, prima di arrivare a sviluppare uno strumento di ascolto più sofisticato, i ricercatori dovranno valutare quali sono i contributi di altre aree che entrano in gioco nel momento in cui il cervello percepisce le parole.
Infatti, nonostante i volontari fossero perfettamente in grado di comprendere i suoni uditi durante i test, i dati estrapolati dalla corteccia uditiva non sono stati sufficienti a crearne una copia perfetta. Dopo tutto, come hanno dimostrato diversi studi condotti durante il coma farmacologico indotto dall' anestesia, le zone del cervello che percepiscono e codificano il significato delle parole agiscono in modo indipendente tra loro. In una prospettiva futura, studi simili a quelli di Pasley potrebbero riuscire a completare il mosaico e stabilire qual è la soglia di coscienza nelle persone che hanno subito danni cerebrali.
Cercetarea arata ca fiecare ceasca de cafea bauta zilnic reduce cu 7% riscul de a suferi de aceasta afectiune, persoanele care beau 4 sau mai multe cesti de cafea zilnic fiind cele cele mai putin expuse riscului de a suferi de diabet de tip 2 (diabet zaharat non-insulino-dependent - nota Redactie TA).
În cercetarea publicata în Journal of Agricultural & Food Chemistry, oamenii de stiinta din China au identificat de ce cafeaua are acest efect. Secretul consta în proteina hIAPP (human islet amyloid polypeptide), care este implicata în diabetul de tip 2. Anumiti compusi din cafea au un efect inhibitor asupra formarii acestor amiloizi toxici, arata studiul cercetatorilor chinezi.
"Rezultatele studiului nostru sugereaza ca efectul benefic al consumului de cafea asupra riscului de a suferi de diabet de tip 2 se datoreaza, cel putin partial, compusilor si metabolitilor din cafea care pot preveni agregarea proteinelor toxice hIAPP. Asadar, persoanele care beau regulat cafea se pot astepta la un efect benefic", au explicat cercetatorii.
In September 2002, one hundred million cubic metres of rock and ice separated from the northern slope of the Kazbek massif in North Ossetia, Russia. The resulting avalanche killed 125 people and caused widespread damage. Ice avalanches can travel great distances at speeds of up to 150 miles per hour, but it is not fully understood how they travel so far or so fast. The difficulty lies in observing the processes within avalanches closely. But by creating a laboratory avalanche one researcher at The University of Nottingham has helped us to understand how melting effects flows of ice — even at temperatures below freezing.
Dr Barbara Turnbull, a member of the Fluid and Particle Processes Group in the University’s Faculty of Engineering, has found that the same layer of liquid water at an ice particle’s surface that helps skaters to skate across an ice rink also enhances ice avalanche speeds. The water lubricates particle contacts, resulting in more collisions and melting, which in turn leads to a snowball effect of ever-faster speeds.
To measure this effect Dr Turnbull half filled a narrow Perspex drum with flash-frozen water droplets, rotating it so that the droplets formed a slope down which the ice granules bounced and slipped — simulating ice avalanches.
“Ice avalanches from collapsing glaciers are not common in populated areas, but that may change as global temperatures rise. The Ossetia avalanche alerted researchers to the urgency of gaining a better understanding of the processes that control such flows,” Dr Turnbull said.
“This is a simple experiment, but it tests the theory that surface melting in ice particles as they collide plays a role in the speed at which avalanches travel — and therefore the amount of damage they can potentially inflict on the local environment and populations.”
Andare in gita scolastica e tornare a casa con in tasca la scoperta che potrebbe salvare il mondo dall’invasione della plastica. Č accaduto a un gruppo di studenti di college della Yale University che, durante un viaggio nella foresta amazzonica in occasione dell’annuale missione sul campo organizzata dal corso Rainforest Expedition Laboratory, ha scoperto una particolare specie di fungo capace di degradare il poliuretano, il Pestalotiopsis microspora.
Nel 2008, come ogni anno, gli studenti del corso di Scott Strobel, docente di biochimica molecolare, si sono recati in Ecuador per raccogliere campioni da studiare in laboratorio una volta tornati al campus di New Haven (Connecticut, Usa). Questa volta però, nel gruppo c’erano un paio di studenti particolarmente brillanti che hanno portato all’incredibile scoperta.
Polyurethane synthesis, wherein the urethane groups — NH-(C=O)-O- link the molecular units.
Il primo è stato Pria Anand: esaminando i propri campioni, ne ha individuato uno che, a contatto con il materiale plastico, dava il via a una reazione di degradazione. Poi è stata la volta di Jonathan Russel. Lo studente ha isolato l’enzima grazie al quale questo fungo – unico al mondo, per quanto se ne sappia - è in grado di sopravvivere a una dieta a base esclusivamente di poliuretano, e per di più in ambiente completamente anaerobico (cioè privo di ossigeno), condizione tipica del fondo delle discariche. Secondo lo studio pubblicato su Applied and Environmental Microbiology, infatti, le proprietà di questa specie fungina potrebbero essere molto utili nel campo del biorisanamento, ovvero il processo di depurazione del suolo a opera di microrganismi, batteri o funghi.
Ed è proprio qui che la scoperta degli studenti statunitensi si fa interessante. Di poliuretano, infatti, sono costituiti molti oggetti di uso quotidiano, dai materassi ai frigoriferi, dai giocattoli alle scarpe. Si tratta insomma di un materiale molto versatile e soprattutto economico, ma decisamente non riciclabile. L’unica speranza di non lasciarlo in eredità ai nostri pronipoti potrebbe essere proprio questo particolare fungo originario della foresta pluviale ecuadoregna.
Cercetarea publicata în European Journal of Neurology sugereaza ca dieta joaca un rol important în prevenirea acestei afectiuni.
Desi nu este clar de ce anumite alimente au un efect protector, unele studii sugereaza ca boala Parkinson poate aparea atunci când celulele din corp trec printr-un proces distructiv denumit "stres oxidativ". În cadrul acestuia, substantele daunatoare (care au patruns în corp din cauza unei diete nesanatoase) ataca celulele într-un mod similar celui în care rugina afecteaza caroseria unei masini.
Fructele, legumele si carnea de peste contin numeroase substante antioxidante, ajutând astfel la prevenirea acestui proces daunator.
Cercetatorii de la Universitatea Tokyo au studiat obiceiurile alimentare a 249 de pacienti diagnosticati recent cu Parkinson, comparând dieta acestora cu cea a 368 de voluntari sanatosi.
Oamenii de stiinta au împartit participantii la studiu în trei grupuri, în functie de dieta. Cei din grupul "dieta sanatoasa" consumau mai ales fructe proaspete, legume, peste, plante leguminoase (linte, fasole, mazare), ciuperci si alge. În dieta celor din grupul "dieta occidentala" predominau carnea rosie si alimentele bogate în grasimi de origine animala, iar dieta persoanelor din grupul "alimente usoare" era o combinatie a celorlalte doua stiluri de alimentatie.
Rezultatele cercetarii au aratat ca persoanele din grupul "dieta sanatoasa" - care consumau cea mai mare cantitate de plante si de peste - prezentau un risc cu 46% mai scazut de a suferi de Parkinson în comparatie cu persoanele cu o dieta saraca în plante si peste.
However, scientists have been unable to explain just why limiting daily food intake has such a beneficial effect on health and the biological mechanisms that underlie the phenomenon. Researchers in Sweden recently claimed to have unlocked a piece of the puzzle by identifying one of the enzymes that appears to play a major role in the process and now another group in the U.S. has provided another clue by tweaking a gene in fruit flies and extending their lifespan by as much as 50 percent.
While initial results are positive, due to the long lifespan of the species, studies on whether caloric intake works in nonhuman primates and humans are ongoing. Fruit flies, on the other hand, have a much shorter lifespan, with the ability to develop from egg to an adult in as little as seven days. This, along with numerous other reasons, has seen the fruit fly become a model organism that is widely used in studies of genetics and physiology.
A team consisting of researchers from the Salk Institute for Biological Studies and the University of California, Los Angeles, took the fruit fly ( (Drosophila melanogaster) and tweaked a gene in their intestinal stem cells known as dPGC-1, which is also found in human DNA and known as PGC-1. This resulted in the aging of the fruit flies' intestines being delayed and their lifespan being extended by as much as 50 percent.
In flies and mammals, the PGC-1 gene regulates the number of mitochondria within an animal's cells. Mitochondria are often referred to as "cellular power plants" because they convert sugars and fats from food into the energy for cellular functions. Since previous studies had shown that calorie-restricted animals have greater numbers of mitochondria in their cells, the researchers set about investigating what would happen when the PGC-1 is forced into overdrive.
Using genetic engineering techniques to boost the fruit fly equivalent of the PGC-1 gene resulted in the same kind of effects seen in organisms on calorie restricted diets - namely, greater numbers of mitochondria and more energy production. When the activity of the gene was accelerated in stem and progenitor cells of the flies' intestine, which serve to replenish intestinal tissues, these cellular changes corresponded with better health and longer lifespan.
Depending on the method and extent to which the activity of the gene was altered, the flies lived between 20 and 50 percent longer than normal.
The researchers say their findings suggest that the fruit fly version of PGC-1 can act as a biological dial for slowing the aging process and might serve as a target for drugs or other therapies to put the brakes on aging and age-related diseases. They theorize that boosting dPGC-1 stimulates the stem cells that replenish the intestinal tissues, thus keeping the flies' intestines healthier.
"Slowing the aging of a single, important organ - in this case the intestine - could have a dramatic effect on overall health and longevity," says Leanne Jones, an associate professor in Salk's Laboratory of Genetics and a lead scientist on the project. "In a disease that affects multiple tissues, for instance, you might focus on keeping one organ healthy, and to do that you might be able to utilize PGC-1."
Riprendersi da uno shock come quello dell'11 marzo 2011 è difficile, così come lo è fidarsi delle centrali nucleari vecchie quanto quella di Fukushima. Infatti, dopo l'incidente che ha messo in ginocchio il Giappone, le autorità governative hanno ordinato lo spegnimento di tutti i 54 reattori presenti sul territorio nazionale eccetto 3.
Ma con il documento approvato ieri dalla International Atomic Energy Agency (Iaea) per il paese potrebbe essere molto più facile riavviare gli impianti. Tutto merito del fatto che gli stress test svolti dall' Agenzia per la sicurezza nucleare (Nisa) sono stati riconosciuti come validi da parte della comunità internazionale.
Ma, come riporta il Guardian, non mancano le critiche, tutte incentrate sulla possibilità che i controlli attuali non siano sufficienti. A dirlo sono Masashi Goto, un ex progettatore di centrali, e Hiromitsu Ino, professore della Tokyo University da sempre attivo nel campo della sicurezza nucleare.
Secondo i due esperti, le procedure di valutazione adottate dalla Nisa si limiterebbero a passare al setaccio le specifiche tecniche degli impianti giapponesi per controllare che questi rispettino le norme vigenti. Insomma, niente di differente da quanto non fosse già stato fatto prima dell'incidente di Fukushima.
A peggiorare le cose, spiega Ino, concorrerebbe il fatto che le indagini sull'incidente dell'11 marzo scorso non sono ancora state in grado di fornire un quadro esatto di cosa sia accaduto all'interno della centrale di Fukushima. Poco importa se i criteri degli stress test pianificati in Giappone ricalcano fedelmente quelli delle prove condotte in Europa.
Nel frattempo, i primi controlli effettuati da Nisa hanno assegnato il bollino verde alla centrale di Oi gestita dalla Kansai Electric Power. Secondo i dati rilasciati dal gestore, sulla carta l'impianto è progettato per resistere a onde di tsunami alte 11,4 metri e a un terremoto 1,8 volte più forte di quanto previsto durante le fasi di costruzione. Di fatto, sono tutti dati che non dimostrano affatto la volontà di condurre test più approfonditi sulla possibilità che si possano verificare anche errori umani o incidenti inattesi.
A tutto questo si aggiunge la proposta varata dal governo giapponese il 25 gennaio scorso, che fissa il limite d'età delle centrali nucleari a 40 anni ma, allo stesso tempo, prevede delle deroghe speciali di ulteriori 20 anni. Sembra quindi che il Giappone non abbia serie intenzioni di dismettere i vecchi reattori con tanta facilità.
Probabilmente, l'esito positivo degli stress test giocherà un ruolo fondamentale nel facilitare il riavvio e il mantenimento in funzione dei reattori over 40. Forse, prima di prolungare la pensione dei reattori di vecchia generazione sarebbe il caso di domandarsi se i danni provocati da una nuova Fukushima potranno essere ancora accettabili.
(p)Link
Commenti
Storico
Stampa
Feed RSS 0.91
Feed Atom 0.3
