Quando a luz branca incide em uma superfície metálica, são removidos elétrons desse material. Esse efeito é utilizado no acendimento automático das luzes nos postes de iluminação, na abertura automática das portas, no fotômetro fotográfico e em sistemas de alarme.

Esse efeito pode ser usado para fazer a transformação de energia

Algumas estimativas apontam que, nos últimos cem anos, a concentração de gás carbônico na atmosfera aumentou em cerca de 40%, devido principalmente à utilização de combustíveis fósseis pela espécie humana. Alguns estudos demonstram que essa utilização em larga escala promove o aumento do efeito estufa.

Outros fatores de origem antrópica que aumentam o efeito estufa são

Placas como a da gravura são usadas para orientar os usuários de um espaço urbano. Essa placa, especificamente, tem a função de avisar que somente

The art of happiness

Nearly every time you see him, he’s laughing or at least smiling. And he makes everyone else around him feel like smiling. He’s the Dalai Lama, the spiritual and temporal leader of Tibet, a Nobel Prize winner, and an increasingly popular speaker and statesman. Why is he so popular? Even after spending only a few minutes in his presence you can’t help feeling happier. If you ask him if he’s happy, even though he’s suffered the loss of his country, the Dalai Lama will give you an unconditional yes. What’s more, he’ll tell you that happiness is the purpose of life, and that “the very motion of our life is towards happiness”. How to get there has always been the question. He’s tried to answer it before, but he’s never had the help of a psychiatrist to get the message across in a context we can easily understand.

LAMA, D.; CUTLER, H. The Art of Happiness: a handbook for living. Putnam Books, 1998.

Pelo título e pela sinopse do livro de Lama e Cutler, constata-se que o tema da obra é

Cyberbullying is harassment through electronic means such as telephone text messages, social media such as Facebook and Twitter or online blogs and bulletin boards. In normal bullying, students are given a daily break from the torment as bully and victim each go to their separate homes. But for victims of cyberbullying, there is no reprieve, as the abuse enters into their private lives. In the US, there are at least 44 states that have anti-bullying laws on the books. While only six of them use the actual word “cyberbullying”, 31 others have laws that specifically mention “electronic harassment”.

Prosecution in the UK is a little more difficult. While all schools are required to have anti-bullying policies in place, cyberbullying itself is not named as a criminal offence. Offenders in the UK would have to be charged under various other laws, including the Protection from Harassment Act of 2003. This makes prosecution much more difficult.

Authorities agree that in order to stop cyberbullying, there has to be parental involvement. Parents need to be vigilant about their children’s access to technology. They should monitor their children’s use of social media, especially children under the age of 14. Bullies are not going to simply disappear, but parents can go a long way in protecting their children from being bullied.

Go! English, ano II, n. 14 (fragmento).

De acordo com o texto, nos Estados Unidos, alguns estados têm leis específicas para assédio via meios eletrônicos. Já no Reino Unido, a instauração de processos contra praticantes de cyberbullying é mais difícil porque