I gradi di separazione di Facebook

I ricercatori di Facebook rivisitano la teoria dei 6 gradi di separazione analizzando 721 milioni di utenti e 69 miliardi di amicizie. Non scoprono molto di nuovo, rispetto agli studi pionieristici di Milgram e Granovetter e quelli più recenti di Duncan Watts, di cui abbiamo parlato qui da poco: i gradi di separazione sono 4-5 e si vanno riducendo nel tempo; le reti nazionali e di coetanei sono più dense.

La buona notizia è che lo studio (o meglio gli studi, perché gli articoli sono 2) sono stati sviluppati anche da ricercatori italiani in un laboratorio dell’Università degli studi di Milano (la mia alma mater).

Qui il link alla notizia del Facebook Data Team:

Anatomy of Facebook

With the rise of modern computing, social networks are now being mapped in digital form, giving researchers the ability to study them on a much grander, even global, scale. Continuing this tradition of social network research, Facebook, in collaboration with researchers at the Università degli Studi di Milano, is today releasing two studies of the Facebook social graph.

Qui quelli agli articoli scientifici:

J. Ugander, B. Karrer, L. Backstrom, C. Marlow. The Anatomy of the Facebook Social Graph.
http://arxiv.org/abs/1111.4503

L. Backstrom, P. Boldi, M. Rosa, J. Ugander, S. Vigna. Four Degrees of Separation.
http://arxiv.org/abs/1111.4570

La British Library digitale: giornali del 18° e 19° secolo

La British Library rende disponibili online 4 milioni di pagine di 200 giornali dei secoli 18° e 19°.

La ricerca nell’archivio è gratis, ma l’accesso alle singole pagine è a pagamento.

Chissà poi perché: curiosa accezione di “servizio pubblico”.

BBC News – British Library scans 18th and 19th-Century newspapers

Four million pages of newspapers from the 18th and 19th Centuries have been made available online by the British Library.

The public will now be able to scan the content of 200 titles from around Britain and Ireland.

[…]

The archive is free to search, but there is a charge for accessing the pages themselves.

[…]

Mr King [the British Library’s head of newspapers] said: “Rather than having to view the items on site at the library, turning each page, people across the UK and around the world will be able to explore for themselves the goldmine of stories and information contained in these pages.”The ability to search across millions of articles will yield results for each user that might previously have been the work of weeks or months, in a matter of seconds and the click of a mouse.”

[…]

A team has spent a year at the British Library’s newspaper library at Colindale, north London, digitising up to 8,000 pages a day.

They expect to scan up to 40 million pages over the next 10 years.

Volontariato

Punto d’incontro tra chi soffre e chi s’offre.

Gli Stati Uniti non amano la scienza? E l’Italia?

In un articolo comparso sul Financial Times del 25 novembre 2011, Gillian Tett si preoccupa perché molti politici americani si dichiarano apertamentamente contrari o indifferenti alla scienza. E da noi? E che conseguenze può avere sul dibattito e sulle scelte di policy?

Why doesn’t America like science? – FT.com

“We have presidential candidates who don’t believe in science!” [Michael Bllomberg, sindaco di New York] lamented, referring to the current field of people jostling to become Republican candidate for the 2012 elections. “I mean, just think about it, can you imagine a company of any size in the world where the CEO said, ‘oh I don’t believe in science’ and that person surviving to the end of that day? Are you kidding me? It’s mind-boggling!”

It is a comment that many observers might echo, particularly among the ranks of American scientists. For while Bloomberg did not specify whom he considers to be “mind-boggling”, the list of targets is long. Thus far, just three of the eight potential Republican candidates have positively declared that they believe in the scientific basis for evolution. The rest have either hedged, or – like Rick Perry – claimed that evolution is just “a theory that is out there… [but] it’s got some gaps in it”. Meanwhile, Michele Bachmann, another contender, has actively called for creationism to be taught too, since she has similar doubts about the evolutionary science.Newt Gingrich has cast doubt on the virtues of stem cell research, Herman Cain has questioned whether there is any scientific evidence behind homosexuality, and most of the candidates have queried climate change. Indeed, whenever any candidate has defended evidence-based science, they have suffered a backlash: witness the travails of Mitt Romney.

In some senses, this is not surprising. A recent survey by the National Science Foundation found that 45 per cent of Americans support evolution (barely more than those who actively reject it). There is similar scepticism about climate change.

The views that Bloomberg considers “mind-boggling” are not outliers, or not outside the coastal areas such as New York, where he resides.

But common or not, the spread of this sentiment is leaving many American scientists alarmed. Last month, New Scientist magazine warned in an editorial that science is now under unprecedented intellectual attack in America. “When candidates for the highest office in the land appear to spurn reason, embrace anecdote over scientific evidence, and even portray scientists as the perpetrators of a massive hoax, there is reason to worry,” it thundered. Some 40,000 scientists have now joined a lobby group called Science Debate, which was founded four years ago with the aim of getting more scientific voices into the political arena. “There is an entire generation of students today who have been taught that there is no objective truth – who think that science is just another opinion,” says Shawn Lawrence Otto, co-founder of Science Debate, who told me that the “situation today is much worse than in 2008”.

Science Debate

sciencedebate.org

Temere il meglio [Proverbi pessimisti 13]

Non è mio, ma di Gene Gnocchi (pensate a volte dove va a nascondersi l’arguzia, come la penicillina nella muffa). E a rigore non è nemmeno un proverbio. Ma non è niente male.

Il Financial Times pubblica la classifica dei ministri economici dell’Unione europea

Il Financial Times pubblica (per il sesto anno) la classifica dei ministri dell’economia e delle finanze delle maggiori economie dell’Unione europea.

Naturalmente, per l’Italia c’è ancora Tremonti, che arriva penultimo.

La classifica dei ministri economici

ft.com

Qui sotto trovate una sintesi dei criteri di giudizio.

FT ranking of EU finance ministers: Striker amid stumblers – FT.com

The FT’s ranking of European finance ministers 2011 is based on political ability, economic performance and credibility in the markets. In each category, the 19 biggest European Union economies and their finance ministers received a ranking from one – the best – to 19. These were combined to give an overall rank.

The political aspect is based on the opinions of seven leading economists who judged the ministers on three criteria: their lucidity, or how well they understood events; their impact on the European stage; and their effectiveness at home.

The economic ranking was modified this year to reflect changes in the demands on finance ministers and their economic stewardship. It was based on seven performance measures: recovery in terms of gross domestic product compared with the pre-crisis peak; growth this year; deficit levels and the change since 2009; debt levels; projected change in unemployment from 2008 to 2013; and, finally, deviation of the country’s current account from balance.

Market credibility is judged by the current yield on outstanding 10-year bonds, as well as an assessment of how this yield has changed.

Neurogastronomia, la scienza del gusto

È noto da tempo che non c’è esperienza del sapore senza olfatto (la lingua è in grado di percepire 4 o al massimo 5 sapori base: salato, dolce, amaro, acido e “glutammico”). Un libro appena pubblicato del professor Gordon M. Shepherd, della Yale School of Medicine, Neurogastronomy: How the Brain Creates Flavor and Why It Matters svela i misyteri del nostro sistema olfattivo e delle complesse interazioni tra bocca, naso e cervello. Salon intervista l’autore.

The science of taste – Food – Salon.com

Gordon M. Shepherd, professor of neurobiology at the Yale School of Medicine, has spent a lifetime researching the brain mechanisms involved in olfaction (our sense of smell) and its impact on flavor perception in the brain. His new book is “Neurogastronomy: How the Brain Creates Flavor and Why It Matters,” out this month from Columbia University Press. Shepherd’s work is anchored in a burgeoning field within neuroscience — figuring out the mysteries behind our olfactory system, the ways in which smells are represented and processed in the brain.

Shepherd argues for the quintessential importance of olfaction in our everyday experience of food. Without smell, Shepherd says, there is no flavor. “Neurogastronomy” takes a detailed look at just how smelling in the nose, mouth and brain produces the unique experience of flavor that we associate with eating our favorite or least-favorite foods.

The Science of Taste

Credit: iStockphoto/apomares (salon.com)