Sabendo que quando as ondas passam de uma região para a outra sua frequência de oscilação não se altera e considerando as medidas indicadas na figura, é correto afirmar que a razão !$ { \large v_1 \over v_2} !$ entre as velocidades de propagação das ondas nas regiões 1 e 2 é igual a

A pedra fundamental do liberalismo costuma ser identificada com Adam Smith, mais especialmente com a publicação de A riqueza das nações, em 1776.

Smith afirma que o mundo seria melhor – mais justo, racional, eficiente e produtivo – se houvesse a mais livre iniciativa, se as atitudes econômicas dos indivíduos e suas relações não fossem limitadas por regulamentos e monopólios garantidos pelo Estado ou pelas corporações de ofício. Prega a necessidade de desregulamentar e privatizar as atividades econômicas, reduzindo o Estado a funções definidas, que delimitassem apenas parâmetros bastante gerais para as atividades livres dos agentes econômicos. São três as funções do governo na argumentação de Smith: a manutenção da segurança interna e externa, a garantia da propriedade e dos contratos e a responsabilidade por serviços essenciais de utilidade pública.

Segundo a doutrina liberal, a procura do lucro e a motivação do interesse próprio são inclinações fundamentais da natureza do homem. Elas estimulam o empenho e o engenho dos agentes, recompensam a poupança, a abstinência presente, e remuneram o investimento. Além disso, premiam a iniciativa criadora, incitando ao trabalho e à inovação. Como resultado, cria-se um sistema ordenador (e coordenador) das ações humanas, identificadas com ofertas e demandas mediadas por um mecanismo de preços. Esse sistema social revelaria de modo espontâneo e incontestável as necessidades de cada um e de todos os indivíduos. O sistema também indicaria a eficácia da empresa e dos empreendedores, sancionando as escolhas individuais, atribuindo-lhes valores negativos ou positivos.

(Neoliberalismo, 2001. Adaptado.)

Considerando a densidade da água constante ao longo de todo o trajeto, assinale a alternativa que indica corretamente o esboço do gráfico de como varia a pressão sobre o peixe amarelo, em função do tempo, nesse deslocamento.

Este é tempo de partido,

tempo de homens partidos.

Em vão percorremos volumes,

viajamos e nos colorimos.

A hora pressentida esmigalha-se em pó na rua.

Os homens pedem carne. Fogo. Sapatos.

As leis não bastam. Os lírios não nascem

da lei. Meu nome é tumulto, e escreve-se

na pedra.

[...]

O poeta

declina de toda responsabilidade

na marcha do mundo capitalista

e com suas palavras, intuições, símbolos e outras armas

promete ajudar

a destruí-lo

como uma pedreira, uma floresta,

um verme.

(Reunião, 1969.)

Organizados da menor para a maior escala, os mapas apresentariam a seguinte ordem:

Pode-se afirmar corretamente que a resistência equivalente entre os pontos A e B da figura, em ohms, é igual a

For the first time, primitive human kidneys have been created in a laboratory dish, by using stem cells. Although the kidneys cannot perform the functions of a fully formed adult kidney, the researchers hope the achievement will someday lead to new ways to treat people suffering from kidney failure. “It’s really exciting,” says Melissa Little, who heads the Kidney Research Laboratory at the Murdoch Children’s Research Institute in Australia. She led the research, which was published Wednesday in the journal Nature. “I think this is a really big advance.”

Kidneys are essential for life. They perform a host of crucial bodily functions, including filtering toxins from the blood and regulating blood pressure and bone density. But kidneys can fail for a variety of reasons, including poisonings, infections and other diseases.

“The problem is that if something goes wrong with your kidneys, there are only two options and these have been the same for 50 years: You either have a transplant or go onto dialysis,” Little says. “So we really need alternative options.” To find alternatives, Little and others have been trying for years to grow kidneys in the lab using cells known as induced pluripotent stem (iPS) cells. “Almost 10 years ago now it was shown that you could take any cell from anybody – like you or me – and actually convince it to go back into the state that’s essentially like the fertilized egg, so it is able to turn into any tissue type,” Little says.

While scientists have been able to use iPS cells to create many types of human cells, using them to create a kidney has proved difficult. The problem has been finding just the right combination of chemical signals to trigger iPS cells into making the various tissues in a kidney. “It’s like a recipe,” Little says. “We put different concentrations and types of growth factors in a certain order into the dish. And then when it gets to a certain size we take all the cells and make it into a ball.” After that, the cells talk to each other, she says. One type of cell will signal to its neighbor, and its neighbor will signal back, and that actually makes them form the appropriate shape.

(www.npr.org. Adaptado.)

For the first time, primitive human kidneys have been created in a laboratory dish, by using stem cells. Although the kidneys cannot perform the functions of a fully formed adult kidney, the researchers hope the achievement will someday lead to new ways to treat people suffering from kidney failure. “It’s really exciting,” says Melissa Little, who heads the Kidney Research Laboratory at the Murdoch Children’s Research Institute in Australia. She led the research, which was published Wednesday in the journal Nature. “I think this is a really big advance.”

Kidneys are essential for life. They perform a host of crucial bodily functions, including filtering toxins from the blood and regulating blood pressure and bone density. But kidneys can fail for a variety of reasons, including poisonings, infections and other diseases.

“The problem is that if something goes wrong with your kidneys, there are only two options and these have been the same for 50 years: You either have a transplant or go onto dialysis,” Little says. “So we really need alternative options.” To find alternatives, Little and others have been trying for years to grow kidneys in the lab using cells known as induced pluripotent stem (iPS) cells. “Almost 10 years ago now it was shown that you could take any cell from anybody – like you or me – and actually convince it to go back into the state that’s essentially like the fertilized egg, so it is able to turn into any tissue type,” Little says.

While scientists have been able to use iPS cells to create many types of human cells, using them to create a kidney has proved difficult. The problem has been finding just the right combination of chemical signals to trigger iPS cells into making the various tissues in a kidney. “It’s like a recipe,” Little says. “We put different concentrations and types of growth factors in a certain order into the dish. And then when it gets to a certain size we take all the cells and make it into a ball.” After that, the cells talk to each other, she says. One type of cell will signal to its neighbor, and its neighbor will signal back, and that actually makes them form the appropriate shape.

(www.npr.org. Adaptado.)

Leia o excerto do poema “Nosso tempo”, de Carlos Drummond de Andrade, publicado originalmente em 1945 no livro A rosa do povo, para responder à questão.