Rede social

Facebook is a social networking service and website launched in February 2004, operated and privately owned by Facebook Inc. As of April 2012, Facebook has more than 900 million active users. Users must register before using the site, after which they may create a personal profile, add other users as friends, and exchange messages, including automatic notifications when they update their profile. Additionally, users may join common-interest user groups, organized by workplace, school or college, or other characteristics, and categorize their friends into lists such as "People From Work" or "Close Friends". The name of the service stems from the colloquial name for the book given to students at the start of the academic year by some university administrations in the United States to help students get to know each other. Facebook allows any users who declare themselves to be at least 13 years old to become registered users of the site.

Facebook was founded by Mark Zuckerberg with his college roommates and fellow students Eduardo Saverin, Dustin Moskovitz and Chris Hughes. The Web site's membership was initially limited by the founders to Harvard students, but was expanded to other colleges in the Boston area, the Ivy League, and Stanford University. It gradually added support for students at various other universities before opening to high school students, and eventually to anyone aged 13 and over. However, according to a May 2011 Consumer Reports survey, there are 7.5 million children under 13 with accounts and 5 million under 10, violating the site's terms of service.

A January 2009 Compete.com study ranked Facebook as the most used social networking service by worldwide monthly active users. Entertainment Weekly included the site on its end-of-the-decade "best-of" list, saying, "How on earth did we stalk our exes, remember our co-workers' birthdays, bug our friends, and play a rousing game of Scrabulous before Facebook?". Quantcast estimates Facebook has 138.9 million monthly unique U.S. visitors in May 2011. According to Social Media Today, in April 2010 an estimated 41.6% of the U.S. population had a Facebook account. Nevertheless, Facebook's market growth started to stall in some regions, with the site losing 7 million active users in the United States and Canada in May 2011. Facebook filed for an initial public offering on February 1, 2012.

Que tal treinarmos um pouco o nosso inglês?

Bovine Spongiform Encephalopathy (BSE), commonly known as mad-cow disease, is a fatal neurodegenerative disease in cattle that causes a spongy degeneration in the brain and spinal cord. BSE has a long incubation period, about 30 months to 8 years, usually affecting adult cattle at a peak age onset of four to five years, all breeds being equally susceptible. In the United Kingdom, the country worst affected, more than 180,000 cattle have been infected and 4.4 million slaughtered during the eradication program.


The disease may be most easily transmitted to human beings by eating food contaminated with the brain, spinal cord or digestive tract of infected carcasses. However, it should also be noted that the infectious agent, although most highly concentrated in nervous tissue, can be found in virtually all tissues throughout the body, including blood. In humans, it is known as new variant Creutzfeldt–Jakob disease (vCJD or nvCJD), and by October 2009, it had killed 166 people in the United Kingdom, and 44 elsewhere Between 460,000 and 482,000 BSE-infected animals had entered the human food chain before controls on high-risk offal were introduced in 1989.

A British inquiry into BSE concluded that the epizootic was caused by cattle, who are normally herbivores, being fed the remains of other cattle in the form of meat and bone meal (MBM), which caused the infectious agent to spread. The cause of BSE may be from the contamination of MBM from sheep with scrapie that were processed in the same slaughterhouse. The epidemic was probably accelerated by the recycling of infected bovine tissues prior to the recognition of BSE. The origin of the disease itself remains unknown. The infectious agent is distinctive for the high temperatures at which it remains viable; this contributed to the spread of the disease in the United Kingdom, which had reduced the temperatures used during its rendering process. Another contributory factor was the feeding of infected protein supplements to very young calves.

The first reported case in North America was in December 1993 from Alberta, Canada.

Another case reported later in May 2003. The first known U.S. occurrence came in December of the same year though it was later confirmed that it was a cow of Canadian origin and imported to the U.S. Canada announced two additional cases of BSE from Alberta in early 2005. In June 2005 Dr. John Clifford, chief veterinary officer for the United States Department of Agriculture animal health inspection service, confirmed a fully domestic case of BSE in Texas. Dr. Clifford would not identify the ranch, calling that "privileged information". A new case of Mad Cow disease was recently found in a dairy cow on April 23, 2012 in California during a planned Agriculture Department surveillance program. United States health authorities were quick to point out that the animal was never a threat to the nation's food supply and claim that this is an atypical case of BSE caused by "just a random mutation that can happen every once in a great while in an animal."

Conheça 10 celebridades que defendem as causas ambientais

Bono Vox




O vocalista da banda U2 é um dos artistas que mais se manifesta na defesa ao planeta. O Cantor apoia campanhas contra a intolerância religiosa, além de outras ações humanitárias.  Bono já foi indicado três vezes ao Prêmio Nobel da Paz.


Alicia Silverstone





A atriz já foi eleita a vegetariana mais sexy do mundo, posição que manteve durante anos. Alicia não consome nenhum alimento de origem animal e não usa peles ou couro, além de ser vista em várias campanhas ambientalistas.


Sigourney Weaver





A atriz de Avatar liderou uma manifestação em Nova York contra a hidrelétrica de Belo Monte. A manifestação contou com cerca de 50 pessoas que solicitavam  ao Presidente Lula que ouvisse os líderes indígenas da região atingida pela construção da hidrelétrica.


Leonardo DiCaprio





O Ator produziu o documentário The 11th Hour, que trata sobre o aquecimento global; além do reality-show ‘ecológico’ Greensburg, sobre a reconstrução ambientalmente correta de uma cidade. Leonardo tem uma fundação com o seu nome que realiza trabalhos de conscientização ambiental.


Paul McCartney





O cantor vegetariano é um dos maiores divulgadores da campanha Monday’s Free(Segunda Sem Carne), onde faz um apelo para que as pessoas deixem de comer carne pelo menos uma vez por semana como forma de contribuir para a questão do combate ao aquecimento global.


Gisele Bündchen





A modelo é embaixadora da Boa Vontade pelo Programa das Nações Unidas para o Meio Ambiente (Pnuma), tem entre as suas inúmeras defesas pelo meio ambiente um trabalho de proteção ao rio Xingu e as tribos ribeirinhas e a criação da floresta Gisele Bündchen Sementes, que fomenta a recuperação de mais de 15 hectares de Mata Atlântica em Campinas e na Bahia.


Casal Pitt-Jolie





O casal Brad Pitt e Angelina Jolie financiou um concurso para a criação e construção de 20 moradias baratas, que fossem baseadas em critérios da construção sustentável. As moradias foram usadas na organização Make It Right, que financia a construção de moradias para as vítimas do furacão Katrina, em Nova Orleans.


Matt Damon





O ator é um dos fundadores da Water.org, que tem como objetivo levar água potável a comunidades carentes do Terceiro Mundo. A Water.org defende o “crédito de água”, conceito que defende a concessão de microcrédito para que as comunidades construam sistemas de água e de saneamento básico.


Daryl Hannah





A ativista já foi presa por protestar contra usinas de carvão, que acabam com montanhas para conseguir retirar o material. A atriz mantém um videoblog dedicado aos assuntos sobre a preservação do meio ambiente.


Christiane Torloni





A atriz, juntamente com o ator Victor Fasano, criou o projeto Amazônia para Sempre, que tem como objetivo principal sensibilizar os cidadãos brasileiros sobre a importância da preservação e a real situação da floresta e interromper a devastação do ecossistema. Em 2009, Christiane entregou ao Presidente Lula o manifesto Carta aberta aos brasileiros sobre a devastação da Amazônia, com mais de 1 milhão de assinaturas.