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Detail-riconoscimento_volti2

Lo afferma uno studio condotto da Marlene Behrmann, David Plaut e Adrian Nestor del Carnegie Mellon, università leader nello studio del sistema nervoso e pubblicato sui Proceedings of the National Academy of Sciences (Pnas). Secondo gli autori il loro risultato cambia le prospettive di ricerca sulla percezione visiva e permetterà lo sviluppo di terapie per soggetti che soffrono di deficit percettivi del sistema nervoso centrale come la prosopagnosia, o mancanza di percezione facciale.

Il riconoscimento di una persona nota avviene attraverso l’analisi del suo viso, la cosiddetta percezione facciale. Finora, gli scienziati hanno creduto che il riconoscimento facciale venisse elaborato separatamente in singole regioni del cervello. I ricercatori del Carnegie Mellon hanno invece rivelato che la percezione visiva è il risultato di una più complessa sinergia tra molteplici aree della corteccia cerebrale, che lavorano insieme per il riconoscimento di un volto.

Per analizzare i meccanismi della percezione visiva, diversi soggetti sono stati sottoposti a esame di Risonanza Magnetica funzionale (fMRI), mentre venivano mostrati volti di persone note. I pazienti dovevano riconoscerli mentre cambiava la loro espressione facciale. Utilizzando mappe dinamiche multivariate, il team di ricerca ha scoperto la presenza nel cervello di una rete di regioni anteriori fusiformi che rispondono in modo diverso a seconda delle identità mostrate. Inoltre, lo studio ha svelato che queste zone contribuiscono equamente nell’elaborazione del riconoscimento e che la regione fusiforme destra gioca un ruolo fondamentale nella rete.

Lo studio ha rivelato quanto in realtà sia articolata per il nostro cervello una operazione - apparentemente molto semplice e rapida - come la percezione visiva. “Il riconoscimento facciale è uno degli esercizi più impegnativi per il nostro sistema nervoso”, ha dichiarato Marlene Behrmann, una delle autrici della ricerca, docente di psicologia ed esperta di bioimmagini del cervello.

Fonte: galileonet.it - Riferimenti: Pnas doi:10.1073/pnas.1102433108

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The brain-computer interface (BCI) technology could one day be used to help people who are unable to talk or have other physical disabilities due to brain injury. The technology could one day be used to read a person’s mind.

Published April 7 in the Journal of Neuroengineering, the study was carried out by scientists at the Center for Innovation in Neurosciences and Technology at Washington University in St. Louis. The team was led by Dr. Eric Leuthardt, a pioneer in the field who previously developed a BCI that enabled people to play video games with their thoughts. In the current study a net of ECoG (electrocorticographic) electrodes was temporarily placed beneath the dura, a layer of connective tissue surrounding the brain. Rather than performing a craniotomy and placing electrodes on the brain for an experiment–might be hard to get approval for that–the original purpose of the electrodes was to map activity in patients with intractable epilepsy so that those areas could be surgically removed. As human brain studies are often brought about, Dr. Leuthardt combined his clinical aims with experimental. The ECoG electrodes detect the activity of underlying neurons and transmit the signals to a computer that then uses the signals to perform a task. In the current study the patients’ brain activity was used to control a cursor on a computer screen. Remarkably, the patients were able to accurately control the cursor in as little as 4 minutes. The slowest of them took 15 minutes. The ease with which the patents were able to perform the task is an encouraging sign that the technology could be applied to prosthetics control.

Other researchers have successfully used a BCI to interact with a computer. What’s novel about Leuthardt’s study was the region of the brain they recorded from. Building off work in monkeys where a mathematical relationship was found between the activity of motor cortex neurons and movements produced, early work in neural interfaces for prosthetic control logically focused efforts of how to use the motor cortex as the brain activity source. Leuthardt’s group, however, took a different approach. They hypothesized that, instead of imagining an arm movement–from right to left, for example–the patient could control the cursor with sounds either spoken aloud or imagined.

Instead of recording from the motor cortex, the researchers needed to record from the speech centers of the brain: Wernicke’s area in the temporal lobe and Broca’s area in the frontal lobe. The patients were asked to say or think of four sounds: oo, ah, ee, and eh. The computer then associated the patterns of brain activity that represented each of the sounds and tied specific cursor movements to the sounds. When the patient said or thought “ah” for example, the cursor would move left.

Using the brain’s speech centers instead of the motor area was a major achievement. Human speech has been studied extensively with brain imaging techniques such as positron emission tomography (PET) or functional magnetic resonance imaging (fMRI). Data from these experiments have revealed a great deal about how different parts of the speech network work together to produce and understand language. But prior to Leuthardt’s demonstration it was not known if speech network activity could be used in BCI control.

Will the computer understand us if we simply talk to it? This is important for neuroprosthetic devices of the future as it expands the repertoire of brain function that clinicians can potentially use to control a robotic limb.

Another way to phrase the above question: can the computer read our minds? Amazingly, the answer seems to be yes. But simple oos and ahs are one thing, articulated thoughts are quite another. When we talk–either to each other or internally to ourselves–our thoughts aren’t limited to the words we’re using. Our brain relates to the words in intuitive ways, as in all of the imagery and associations that pop up in our heads when we hear a simple word like “ninja.” BCIs are a long way off from extracting the tremendously more complex idea of ninja our brain conjures up, but understanding overt statements from the brain is a step in that direction. It’s fun to think that this technology might be used someday to record our thoughts in the same way tape recorders are used. Brain implants could enable us to “jot down” lecture notes in our thoughts and retrieve them from the computer later. You’ll definitely want to keep those notes heavily guarded, lest someone hacks in and realizes that your mind kept wandering to the cute girl in the row next to you.

Computers are already being used to read our minds–and companies are cashing in on the data. Neuromarketing is a field born when a neuroscientist performed the Pepsi Challenge while scanning people’s brain activity with fMRI. The study showed that a part of the brain called the medial prefrontal cortex lights up when people really like a product. As before, Pepsi beat Coke and when they drank Pepsi the MPC lit up. But then why, if more people prefer Pepsi, does Coke dominate the market? The answer came when researchers uncovered the labels. Now that the people knew what they were drinking, the MPC lit up with Coke, not Pepsi. The conclusion was that Coke’s advertising was much more effective than Pepsi’s: even though people preferred Pepsi, they thought they preferred Coke. Lighting up the MPC meant a refreshed and satisfied Coke drinker. Thus, a cottage industry was born. Companies began putting people in MRI machines and testing their slogans and ad campaigns, and watching to see if the MPC lit up. If it did, it meant the consumer was thinking, “I need that pair of shoes.”

The potential of combining mind and machine is limitless. The two are being brought ever closer as developments in BCI technology proceed in parallel with our increasing understanding of the how the brain works. The future of BCIs will take us in even more exciting and unpredictable directions. Whether it improves the lives of disabled people, enhances our use of information, makes video games more fun, or makes companies money only time will tell. Eventually, I have no doubt, it will be all of the above and more.

Source: Singularity Hub

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By Admin (from 26/08/2011 @ 14:00:20, in ro - Observator Global, read 649 times)

 Mentionata documentar in 1043, Copenhaga a primit statut de oras in 1254. Originile sale se afla nu departe, pe insula Slotsholmen, unde s-a construit un castel care actualmente este sediul guvernului danez. Castelul a fost ridicat de episcopul Albsalom de Roskilade, care a sesizat importanta strategica a insulei pe care la 1026 nu se afla decât un mic sat de pescari. Satul se numea Havn ((Port) si particula respectiva o intâlnim si in numele de astazi a orasului care in daneza este Kolnhavn.

In 1455 a primit statut de capitala dupa ce fusese distrusa de invadatorii din nordul Germaniei si reconstruita in 1369. Regele Danemarcei se mutase in oras inca din 1416 si importanta asezarii a crescut considerabil. La sfârsitul secolului al XVI-lea, datorita comertului infloritor, Copenhaga devine deosebit de bogata. In secolul al XVII-lea, in timpul domniei regelui Christian al IV-lea, recunoscut drept mare iubitor de arta s-au ridicat cele mai frumoase constructii din oras.

Printre acestea se numara observatorul astronomic Rundentarn, Bursa decorata cu imagini in forma de coada de dragon si castelul Rosenborg in care se pastreaza bijuteriile Coroanei. Nenorocirile de tot felul nu au ocolit insa orasul. In 1711 este bântuit de ciuma si in 1728 si 1795 este mistuit de incendii. In 1807 este bombardat de flota engleza dar este imediat reconstruit.

Reusind sa-si revina din aceste lovituri cumplite, locuitorii au cunoscut apoi o perioada de mare inflorire culturala. Acum se remarca prin activitatea lor, oameni de seama ca filozoful Soren Kirkegaard, scriitorul Hans Christian Andersen si Christoffer Wilhelm Eckersberg, fondatorul Scolii de Arte Frumoase daneze.

In 1849, Danemarca devine monarhie constitutionala si sapte ani dupa acest eveniment sunt darâmate vechile ziduri ale orasului. Verdeata a acoperit batrânele bastioane construite pe cheiurile de la Christianshavn intre 1662-1665 si locuitorii si-au amenajat aici locuinte. Dupa 1971 câmpul de instructie de la Christiania a fost invadat de membrii miscarii hippy care si-au proclamat aici propriul stat liber. Enclava a fost initial contestata vehement si, in cele din urma tolerata, devenind un loc unde nu exista chirie sau automobile si unde poti intâlni acum un amestec boem si chiar artisti de valoare. In partea opusa acestei zone, turnul primariei, inalt de peste 100 de metri domina piata principala.

O atractie a orasului este parcul de distractii Tivoli, deschis in 1834. Impresionante sunt aici nu doar caruselele si roata mare, Ferris, ci si spectacolele traditionale sau clasice organizate in marea sala a complexului. In apropierea acestui parc se afla Ny Carlsberg Gliptothek, o mare galerie de arta construita de magnatul berii Carlsberg, Carl Jakobsen. Sunt expuse aici obiecte de origine etrusca, tablouri franceze si daneze si o apreciata colectie de pictura post-impresionista franceza.

Muzeul National expune si el o serie de piese valoroase vechi, printre acestea aflându-se un car de lupta cu o vechime de peste 3500 de ani. Simbolul orasului ramâne insa statuia Micii Sirene realizata de sculptorul Edward Ericksen. De pe stânca de pe care priveste intinderea de ape, sirena de bronz aduce un plus de poezie orasului parând sa vegheze asupra corabiilor venind din larg.

IRINA STOICA - magazin.ro

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A 10 anni dalla loro scoperta, infatti, fanno il loro ingresso nella tavola periodica degli elementi due nuovi atomi superpesanti, nelle caselle 114 e il 116. L’ Unione Internazionale di Chimica Pura ed Applicata (Iupac) e l’ Unione Internazionale di Fisica Pura ed Applicata (Iupap), infatti, hanno appena sciolto le loro ultime riserve e reso ufficiale l’entrata di questi due nuovi elementi nel regno di Mendeleev.

Detail-elementi chimici

Il numero di massa (cioè di protoni e neutroni all’interno del nucleo) delle due new entry è, rispettivamente, 289 e 292. Li precedono il roentgenio (casella 111, peso atomico 272) e il copernicio (casella 112 e peso atomico 285), l’ultimo ad essere stato riconosciuto, nel 2009 (vedi Galileo).

Essendo superpesanti, i due elementi sono altamente instabili (radioattivi) e decadono velocemente, perdendo particelle alfa. Il 116 diventa 114 in meno di un secondo, e questo a sua volta decade nel copernicio. Questo il motivo per cui sono serviti più di dieci anni per la raccolta delle prove sulla loro esistenza, e tre anni per la revisione di tutti i dati. Ad accumulare evidenze hanno cominciato i russi e gli americani, nel lontano 1999. Bombardando il plutonio 244 (cioè con 244 protoni e neutroni) con il calcio 48, i fisici erano riusciti a creare un atomo con numero di massa di 292 (244 + 48): era il 116. Questo decadde però immediatamente in un elemento con 289 protoni e neutroni: così, in un colpo solo, ecco anche il 114.  

Ricevuto il riconoscimento della comunità scientifica, ai due manca però ancora il nome; provvisoriamente si chiamano ununquadium e ununhexium. I papà russi hanno proposto flerovio per il 114, in onore del suo scopritore sovietico Georgy Flyorov, e moscovio per il 116, in onore della Oblast di Mosca.

Per la cronaca, sono attualmente in attesa di essere riconosciuti come legittimi altri tre elementi: 113, 115 e 118 (vedi Galileo). Chissà che nel 2011, Anno internazionale della chimica, non entreranno anche loro nella tavola periodica.

Fonte: galileonet.it - Riferimenti: wired.it

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Air capture, in which carbon dioxide is removed from the atmosphere, has been touted as a potentially promising way to tackle climate change. That's because unlike carbon capture from power plant flue gases, the technology has the potential to reduce existing CO2 levels, rather than simply slowing the rate of increase.

Power.jpg

To demonstrate that the technology works, Christopher Jones at the Georgia Institute of Technology in Atlanta tested a CO2 absorbent based on amines - the chemicals predominantly used in power plant carbon capture trials - on gases with CO2 concentrations similar to those found in ambient air.

He found the material was able to repeatedly extract CO2 from the gas without being degraded, which will be vital if the technology is to be used economically on a wide-scale.

However, unlike the liquid amines typically used in power plant carbon capture, which consume large amounts of energy as they must be heated to very high temperatures to re-release their stored CO2, Jones' team has developed a new class of the material called hyperbranched aminosilica, in which the amine is held on a solid porous silica substrate.

Solid amines release the stored CO2 when heated to just 110 degrees Celsius - much lower than the temperatures required by the water-based liquid amine solutions - reducing the amount of energy required by 75 per cent.

This also means the energy needed could be supplied by widely available sources such as waste heat from industrial plants, says Peter Eisenberger of air capture company Global Thermostat, based in New York. The energy could also be supplied by renewable sources such as solar power, he says. The captured CO2 could then be fed to algae, which absorb the gas to produce biofuel and biochar.

Jones is working with the company to test a pilot air capture plant in Menlo Park, California, which is absorbing 2 tonnes of CO2 from the atmosphere each day. A commercial plant could absorb 1 million tonnes of CO2 per day, says Eisenberger.

Source: NewScientist

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Chenglong Li, Ph.D., an assistant professor of medicinal chemistry and pharmacognosy at The Ohio State University (OSU), is leveraging a powerful computer cluster at the Ohio Supercomputer Center (OSC) to develop a drug that will block the small protein molecule Interleukin-6 (IL-6). The body normally produces this immune-response messenger to combat infections, burns, traumatic injuries, etc. Scientists have found, however, that in people who have cancer, the body fails to turn off the response and overproduces IL-6.

"There is an inherent connection between inflammation and cancer," explained Li. "In the case of breast cancers, a medical review systematically tabulated IL-6 levels in various categories of cancer patients, all showing that IL-6 levels elevated up to 40-fold, especially in later stages, metastatic cases and recurrent cases."

In 2002, Japanese researchers found that a natural, non-toxic molecule created by marine bacteria -- madindoline A (MDL-A) -- could be used to mildly suppress the IL-6 signal. Unfortunately, the researchers also found the molecule wouldn't bind strongly enough to be effective as a cancer drug and would be too difficult and expensive to synthesize commercially. And, most surprisingly, they found the bacteria soon mutated to produce a different, totally ineffectual compound. Around the same time, Stanford scientists were able to construct a static image of the crystal structure of IL-6 and two additional proteins.

An electrostatic representation (red: negative; blue: positive; white: hydrophobic) created at the Ohio Supercomputer Center by Ohio State’s Chenglong Li, Ph.D., shows IL-6 in ribbon representation. The two larger yellow ellipses indicate the two binding "hot spots" between IL-6 and GP130, key to blocking a protein that plays a role in breast and prostate cancer. (Credit: Chenglong Li/OSU)

Li recognized the potential of these initial insights and partnered last year with an organic chemist and a cancer biologist at OSU's James Cancer Hospital to further investigate, using an OSC supercomputer to construct malleable, three-dimensional color simulations of the protein complex.

"The proximity of two outstanding research organizations -- the James Cancer Hospital and OSC -- provide a potent enticement for top medical investigators, such as Dr. Li, to conduct their vital computational research programs at Ohio State University," said Ashok Krishnamurthy, interim co-executive director of OSC.

"We proposed using computational intelligence to re-engineer a new set of compounds that not only preserve the original properties, but also would be more potent and efficient," Li said. "Our initial feasibility study pointed to compounds with a high potential to be developed into a non-toxic, orally available drug."

Li accessed 64 nodes of OSC's Glenn IBM 1350 Opteron cluster to simulate IL-6 and the two additional helper proteins needed to convey the signal: the receptor IL-6R and the common signal-transducing receptor GP130. Two full sets of the three proteins combine to form a six-sided molecular machine, or "hexamer," that transmits the signals that will, in time, cause cellular inflammation and, potentially, cancer.

Li employed the AMBER (Assisted Model Building with Energy Refinement) and AutoDock molecular modeling simulation software packages to help define the interactions between those proteins and the strength of their binding at five "hot spots" found in each half of the IL-6/IL-6R/GP130 hexamer.

By plugging small molecules, like MDL-A, into any of those hot spots, Li could block the hexamer from forming. So, he examined the binding strength of MDL-A at each of the hexamer hotspots, identifying most promising location, which turned out to be between IL-6 and the first segment, or modular domain (D1), of the GP130.

To design a derivative of MDL-A that would dock with D1 at that specific hot spot, Li used the CombiGlide screening program to search through more than 6,000 drug fragments. So far, he has identified two potential solutions by combining the "top" half of the MDL-A molecule with the "bottom" half of a benzyl molecule or a pyrazole molecule. These candidates preserve the important binding features of the MDL-A, while yielding molecules with strong molecular bindings that also are easier to synthesize than the original MDL-A.

"While we didn't promise to have a drug fully developed within the two years of the project, we're making excellent progress," said Li. "The current research offers us an exciting new therapeutic paradigm: targeting tumor microenvironment and inhibiting tumor stem cell renewal, leading to a really effective way to overcome breast tumor drug resistance, inhibiting tumor metastasis and stopping tumor recurrence."

While not yet effective enough to be considered a viable drug, laboratory tests on tissue samples have verified the higher potency of the derivatives over the original MDL-A. Team members are preparing for more sophisticated testing in a lengthy and carefully monitored evaluation process.

Li's project is funded by a grant from the Department of Defense (CDMRP grant number BC095473) and supported by the award of an OSC Discovery Account. The largest funding areas of Congressionally Directed Medical Research Programs (CDMRP) are breast cancer, prostate cancer and ovarian cancer. Another Defense CDMRP grant involving Li supports a concurrent OSU investigation of the similar role that IL-6 plays in causing prostate cancer. Those projects are being conducted in collaboration with Li's Medicinal Chemistry colleague, Dr. James Fuchs, as well as Drs. Tushar Patel, Greg Lesinski and Don Benson at OSU's College of Medicine and James Cancer Hospital, and Dr. Jiayuh Lin at Nationwide Children's Hospital in Columbus.

"In addition to leading the center's user group this year, the number and depth of Dr. Li's computational chemistry projects have ranked him one of our most prolific research clients," Krishnamurthy noted.

Source: Science Daily

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By Admin (from 25/08/2011 @ 11:00:58, in ro - Observator Global, read 555 times)

 Asezat pe malul estuarului fluviului Schelde, orasul Anvers, numit astfel in valona, sau Antwerpen, in flamanda, este unul dintre cele mai mari porturi din lume si principalul centru economic al Belgiei. Intemeiat in secolul al VII-lea, cunoaste o dezvoltate rapida incepând din secolul al XIII-lea. Dupa caderea orasului Bruges, in secolul al XV-lea, devine cel mai bogat oras din Tarile de Jos si principal centru financiar al Europei. Din 1460 aici functioneaza prima bursa din lume dar la sfârsitul secolului al XVI-lea orasul este distrus de spanioli. Din secolul al XIX-lea cunoaste o noua perioada de prosperitate, actuala inflorire economica datorându-se construirii Canalului Albert (1930-1939).

Anversul nu este numai un oras incarcat de istorie, o forta economica de prim rang ci si un loc emanând o frumusete aparte. Muzeul Regal de Arte Frumoase este o dovada concreta in acest sens. Portalul este flancat de coloane masive iar scarile te conduc spre o sala impunatoare ca o catedrala. Sunt expuse tablouri ale maestrilor flamanzi timpurii pentru ca arta a gasit aici o gazda primitoare.

In perioada de inflorire din secolele XV-XVI, Anversul si-a ridicat cladirile care alcatuiesc embleme ales orasului de astazi. Atunci au fost inaltate Primaria, casele breslelor, biserici si palate si mai ale Catedrala a carei constructie a durat 269 de ani. La frumusetea de netagaduit a orasului si-au adus contributia marii pictori care au lucrat aici. Printre acestia trebuie amintiti Antonis van Dyck, Jacob Jordaens, Frans Snyders, Peter Paul Rubens, Jan Bruegel.

Reinvierea portului de la sfârsitul secolului al XIX-lea a dus si la ridicarea unor noi palate si la constructia unor strazi largi strajuite de copaci. Palatele neoclasice si resedintele art nouveau fac o concurenta prieteneasca noii cladiri a garii, care cu cupola ei si zidurile in stil neo-baroc, te invita sa patrunzi in marea sala, pregatita parca sa intâmpine oaspetii unei importante receptii. Orasul a acceptat usor si fara prejudecati arta de avangarda si, in secolul trecut, a devenit un centru al artei experimentale. Din 1950 parcul Middelheim este un adevarat muzeu al sculpturii moderne, unic in Europa. In acelasi timp Anversul este si o cetate a modei, magazinele haute-couture fiind printre cele mai apreciate nu numai pe batrânul continent.

Locul de referinta al orasului ramâne insa Grote Markt cu cladirea primariei, lunga de 67 metri, flancata de casele breslelor, si având in fata statuia lui Brabo. Acesta este un personaj legendar, un roman despre care se spune ca a ucis un urias care oprise navigatia pe Schelde. In apropiere se afla Catedrala inchinata Fecioarei, cu un turn inalt de 123 metri, al doilea nemaifiind terminat. Nu departe de gara poti intâlni evreii ortodocsi (habotnici) purtând palarii cu boruri largi din blana si perciuni lungi.

Alungati din Peninsula Iberica, acum aproape 500 de ani, au gasit in Anvers o gazda buna si s-au implicat puternic in slefuirea diamantelor. Orasul a devenit centrul mondial al comertului cu diamante, 70 la suta din comertul cu aceste pietre trecând pe aici. Stralucirea lor nu reuseste insa sa umbreasca lumina degajata de vechile constructii ale orasului de pe Schelde.

IRINA STOICA - magazin.ro

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Questa la denuncia che arriva da un rapporto sullo stato della repressione su Internet presentato all'Assemblea generale dell'Onu da Frank La Rue, esperto indipendente del Consiglio sui diritti umani.

Detail-internet freedom2

Il web rientra già a pieno titolo tra i mezzi d'informazione il cui libero accesso è sancito dall'articolo 19 della Dichiarazione universale dei diritti dell'uomo. Tuttavia, dal rapporto di La Rue sono emersi dei dati allarmanti: negli ultimi anni, infatti, sono aumentate le forme di violenza e repressione illegittime esercitate da parte di regimi autoritari e monopoli privati ai danni dei due miliardi di utenti connessi a internet.

Le misure restrittive che limitano la libertà di espressione sul web vengono spesso invocate dagli Stati con il pretesto di contenere l'insorgenza di movimenti terroristici. In questo modo, i blocchi e i filtri a internet vengono imposti dai governi facendo ricorso a leggi fuori dall'ordinario, ovvero dei provvedimenti che azzerano i diritti civili per perseguire un'idea di 'sicurezza nazionale' alquanto distorta. “In molti Stati, la libertà di espressione online viene ancora criminalizzata” – ha spiegato La Rue – “e lo dimostra il fatto che nel 2010 siano stati imprigionati più di 100 blogger. I governi, inoltre, fanno ricorso a tecnologie sempre più sofisticate per bloccare contenuti del web e monitorare e identificate attivisti e dissidenti politici”.

Proprio per combattere questo crescente ricorso a norme liberticide, il rapporto La Rue ha invocato la necessità di ridurre al minimo gli atti di censura tout court sul web. Le uniche eccezioni dovrebbero essere regolate in base a norme internazionali che mirino a punire e contrastare episodi di conclamata gravità. Si parla quindi di perseguire casi di pedopornografia, grave diffamazione e istigazione all'odio razziale e al genocidio.

Non mancano, poi, importanti riferimenti di La Rue al ruolo dei privati nella gestione dei contenuti online. Secondo il rapporto, aziende come Google, Facebook o i gestori del traffico online non dovrebbero mai avere il potere di censurare la libertà di espressione dei propri utenti. Tutti i loro interventi dovrebbero essere, cioè, legittimati da una decisione giudiziaria indipendente dai poteri politici.

Nonostante tutto, non sempre la legge è dalla parte dei cittadini. Due paesi democratici come Francia e Inghilterra hanno recentemente approvato delle leggi che consentono di sospendere per un anno la connessione a Internet a tutti coloro che scaricano musica e film da siti pirata. Una decisione forse eccessiva che, nel tutelare i diritti d'autore di un privato, arriva a punire i cittadini limitandone la libertà di espressione.

Come hanno dimostrato le rivoluzioni nel Maghreb, il web è diventato il primo mezzo di comunicazione attraverso cui le persone possono ancora esprimere liberamente le proprie opinioni. I servizi di social networking hanno permesso di bypassare i canali di informazione controllati e filtrati dai regimi autoritari, dando così voce agli oppressi. Dall'altra parte c'è, invece, il caso della Cina, dove Google aveva accettato di censurare molti dei contenuti visualizzabili sul suo motore di ricerca.

Proprio per questo motivo, secondo La Rue, la tutela della libertà di espressione non può essere lasciata nelle mani dei privati e l'accesso a Internet dovrebbe diventare, a tutti gli effetti, un diritto inalienabile dell'uomo, come già è stato sancito da paesi come Finlandia, Estonia e Costa Rica.

Fonte: galileonet.it

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The group’s results were published in the March 25 issue of Science, the nation’s premier science journal. Liu was lead author on the article, which was titled "Self-Recognition Among Different Polyprotic Macroions During Assembly Processes in Dilute Solution."

Inorganic molecules achieve self-recognition

“Publication of this work in Science is important recognition of the research being conducted in Tianbo’s lab,” said Robert Flowers, department chair and professor of chemistry. “His ability to succeed at such a high level shows that first-rate science is being done at Lehigh.”
Liu’s group has spent several years exploring the fascinating solutions of large, soluble ions called macroions. The behavior of these ions is completely different from the behavior of small ions, such as sodium chloride.

Despite being water-soluble and carrying the same type of charge, macroions tend to attract each other with surprising strength, says Liu, and to form very stable, uniform, single-layered hollow spheres known as “blackberry structures.” The structures are common when ions become large, and they mimic some biological processes such as the virus capsid shell formation.

Forming two distinct blackberry structures

Exciting discoveries have been generated from blackberry solutions. Liu’s group found that, when mixed into the same solution, two different types of 2.5-nm spherical macroions ({Mo72Fe30} and {Mo72Cr30}) with almost identical size, shape and molecular structures tend to form two types of individual blackberries instead of mixed ones.

The macroions—Bucky ball-shaped inorganic compounds—were synthesized by a research team led by Achim Müller, professor of chemistry at the University of Bielefeld, Germany. Müller was a coauthor on the Science article.
This result, says Liu, suggests that even in dilute solutions these two macroions can self-recognize during assembly.

This level of “intelligence,” he adds, is usually believed to be achievable only by complex biological molecules. Self-recognition by large inorganic ions could lead to more opportunities for understanding the nature of biological interactions.

Liu’s group believes the self-recognition results from the very slow formation of the dimers in the first step of the assembly. The slow speed ensures the formation of dimers with the lowest free energy, such as A-A and B-B dimers.
The differences in charge density between the two types of macroions play an important role in the recognition, says Liu, as does their surface water mobility difference.

Source: PhysOrg

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By Admin (from 24/08/2011 @ 11:00:33, in ro - TV Network, read 805 times)

 Ce usor e pentru unii sa spuna, în anumite momente ale vietii: M-am saturat, plec acolo unde n-o sa ma gaseasca nimeni! Mai greu este sa se tina de cuvânt, iar Paul Gauguin, rebelul suparat foc pe arta europeana a epocii sale, a fost unul dintre aceia care chiar si-a luat talpasita spre o insula paradisiaca a Oceanului Pacific, în Polinezia franceza, Insulele Marchize. Acolo, în „Cimitirul Calvarului” din localitatea Atuona, statea singur un pictor major al postimpresionismului, din 1903. Dar în 1978, un alt mare artist europeran avea sa i se alature. Belgianul Jacques Brel a fost înmormântat tot acolo, dupa lungi rataciri pe mare, stiind ca are cancer la plamâni. Brel si Gauguin nu s-au întâlnit altfel decât la capatul lumii, acolo unde, poate, începe o alta lume.

Francezul pe jumatate peruan (dupa mama) este unul dintre acei maestri inconfundabili ai elitei picturii universale caruia îi recunosti imediat culorile îngrosate, tipatoare si contrastante, ca si usoara neglijare a formelor. Încadrat de critica în curentul primitivismului, inspirat din arta africana si asiatica, Gauguin a anticipat si fovismul – „disperarea cromatica”.

Numai ca biografia acestui nonconformist a fost la fel de palpitanta precum preocuparea sa obsedanta de a gasi prin arta raspunsul la întrebari esentiale ale existentei. Refugiul sau pe tâmuri la care altii nici nu viseaza a fost, de fapt, o prelungire a unei vieti careia nu-i mai gasea sensul. Alcoolic depresiv, maestrul a încercat sa se sinucida si în perioada celor noua saptamâni cât a batut tavernele alaturi de „bizarul” sau amic, Vincent van Gogh (la Arles, în sudul Frantei). Cei doi amici erau chiar sa se omoare într-o seara, iar ulterior olandezul si-a taiat urechea pentru a o face cadou unei prostituate...

Din pacate, Paul Gauguin a fugit de arta prea „conventionala” a Europei, si-a cladit cu arme strict personale un stil si o tematica cu totul noi, dar nu a putut fugi de negurile din sufletul sau. Tahiti i-a oferit salbaticia de care avea nevoie, iar amantele adolescentine de prin partea locului i-au adus trecatoare clipe de fericire. Pastoral si mistic, maestrul încerca sa comunice cu divinitatea (poate chiar cu zeitatile locale), careia îi cerea cu insistenta sa dezvaluie „De unde venim?” (titlul capodoperei sale, realizate în 1897).

Nelinistile spiritului sau se exteriorizau cu vehementa si la capatul lumii, Gauguin razboindu-se atât cu reprezentantii bisericii, cât si cu autoritatile laice. Si-a riscat cu seninatate atât sanatatea, cât si libertatea, fiind închis trei luni. Material, practic traia la limita si doar datorita unui dealer de arta – Ambroise Vollard – mai primea bani din tara. Baraca în care vietuia ne aduce aminte de bojdeuca lui Creanga, iar o data cu trecerea anilor tinerele sale prietene îl suportau cu greu.

Singurele momente de detasare fata de o lume pe care nu o mai întelegea le-a parcurs atunci când a scris lucrarea „Înainte si dupa” – memoriile vietii tahitiene, opinii despre literatura si arta. Însa starea sa psihica se agrava si certurile cu autoritatile se acutizau pe zi ce trecea. Se simtea încoltit pe nedrept din toate partile. Într-o stare deplorabila, Paul Gauguin se stinge la cincizeci si patru de ani – probabil de sifilis. Era anul 1903. Dupa un secol, în 2003, la Atuona s-a deschis Centrul Cultural Paul Gauguin.

PAUL IOAN - magazin.ro

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