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Partículas de raios cósmicos alojadas no gelo podem dar pistas sobre mudanças climáticas


Gelo guarda isótopos de berílio, que se desprendem quando raios entram na atmosfera. (Foto: Adriana Moreira/AE)

Cientistas australianos buscam na Antártida evidências de partículas de raios cósmicos, provenientes de supernovas, que ficaram alojadas no gelo, para estudar seu impacto no clima da Terra durante o último milênio, informou a imprensa local nesta quinta-feira, 9.

Os físicos Andrew Smith e Ulla Heikkila, da Organização Australiana de Tecnologia e Ciência Nuclear, viajaram até o continente branco para colher amostras de gelo e medir a presença de isótopos de berílio, partículas que se desprendem quando os raios cósmicos se chocam com o oxigênio ao entrar na atmosfera terrestre.

“Com as amostras de núcleos de gelo de berílio poderemos ter um indício real de como a atividade solar afetou o clima da Terra no último milênio”, explicou Smith à emissora australiana “ABC”.

O Sol tem papel “protetor” contra os raios cósmicos graças à heliosfera, uma espécie de bolha criada pelos ventos solares para desviar os raios, destacou Smith.

Se a atividade solar é menor, a heliosfera fica debilitada e permite uma entrada maior de raios cósmicos na atmosfera terrestre, gerando mais isótopos de berílio que ficam depositados ao longo do tempo nas camadas de neve na Antártida.

Os pesquisadores esperam encontrar amostras milenares no leste do Polo Sul e pretendem submetê-las a testes especializados nos laboratórios.

Smith e Ulla procuram obter a história do acúmulo de berílio na Terra para depois desvendar a história da atividade solar.

Os dois cientistas explicaram que as oscilações na quantidade de energia emitida pelo Sol tiveram um papel pouco significativo na mudança climática no último século, porém não descartam que durante períodos maiores de tempo tenham tido uma importância mais relevante.

“A relação histórica entre a atividade solar e a mudança climática da Terra” é um dos aspectos que o estudo poderá esclarecer.

Fonte: Estadão
Original: http://bit.ly/y5Hpr2


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The bid to build a sea water-to-drinking water facility at Huntington Beach is cleared by a regional water board. But environmentalists say the plan endangers sea creatures and risks fouling the ocean with discharge.

The bid to bring a large-scale desalination plant to Southern California cleared a major hurdle Friday when water regulators approved a permit for a Huntington Beach facility to turn seawater into drinking water.

Connecticut-based firm Poseidon Resources is proposing a seawater desalination plant on a 12-acre site next to a coastal power plant, which is adjacent to a popular state beach.

According to the company, it would be the largest such facility in the Western Hemisphere. The $350-million facility, they said, would supply 50 million gallons of drinking water a day — enough to supply 300,000 people.

Although local water agencies, lawmakers and the business community generally support building the plant, environmentalists say its ocean water intake system would kill fish, plankton larvae and other sea creatures, while spitting extra salty water known as “brine” back into the ocean. The discharged water would be tainted with iron and cleaning fluids, critics say.

The project, approved by the Santa Ana Regional Water Quality Control Board at a meeting Friday in Loma Linda, had to be retooled by Poseidon, whose earlier plans to draw water released from the AES natural gas-fueled power plant were stymied by new regulations.

A state policy adopted in 2010 will phase out the use of seawater to cool coastal power plants, a process that kills fish, larvae, eggs, seals, sea lions, turtles and other creatures when they get trapped against screens or sucked into the plant and exposed to heated water.

The new policy by the state water board would end seawater cooling at the Huntington Beach power plant as early as 2020, but it does not apply to stand-alone desalination plants.

Conservation groups say the company’s new proposal seeks to bypass those restrictions.

“It’s going to perpetuate the use of the type of cooling that the state tried to eliminate,” said Ray Hiemstra, associate program director for Orange County Coastkeeper, a watershed conservation group. “It’s just perpetuating a killing machine.”

The company says environmental groups exaggerate the toll on sea life.

Scott Maloni, a vice president for Poseidon Resources, said the impact on marine life would be insignificant “in exchange for producing a drought-proof drinking-water supply for 300,000 people.”

Supporters, including local public water agencies, building and chamber groups and a number of state and local lawmakers, say the desalination plant would provide a reliable, local water supply for Orange County, which relies mostly on imported water.

Some half a dozen desalination plants are under consideration along the California coast, but only a handful of small facilities and demonstration projects have been built.

Poseidon is further along on a proposal to build a similar desalination plant in Carlsbad and has asked for the state’s permission to issue $780 million in tax-exempt bonds to help pay for it. The firm could break ground on that facility as early as this summer, Maloni said. The earliest the Huntington Beach plant could start operating is 2016, the company said.

Poseidon’s only previous attempt at a desalination plant was not successful. Tampa Bay Water bought out Poseidon’s interest in the Apollo Beach, Fla., facility after contractors filed for bankruptcy. The plant, which uses water from Tampa Bay, was shut down for several years for repairs and, since coming back online, has had difficulties meeting its promised 25 million gallons a day.

The Huntington Beach project, which has been in the works for more than 12 years, still needs approval from the state Coastal Commission to move forward.

The project is certain to get another hearing; environmental groups said they would appeal the decision to the state water board. State water regulators are collecting scientific and technical data in order to draft new policies on seawater intake specific to desalination plants. The policies could be adopted in the next year.

Author: Tony Barboza
Source: Los Angeles Times
Original: http://lat.ms/zfNe6T


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Expedições de naturalistas da Universidade de Coimbra resultaram numa vasta colecção de exemplares de flora. (Foto: DR)

O botânico Jorge Paiva, 78 anos, professor e investigador reformado da Universidade de Coimbra, corre dez quilómetros todos os dias. A sua forma física vai ser necessária agora para uma nova tarefa: servir de guia em quatro documentários que serão produzidos até 2013, sobre as missões botânicas da universidade em África.

Para entender o que significam estas missões, basta olhar para o herbário da universidade. Ali estão hoje armazenados cerca de 700.000 exemplares de flora – a maior colecção do país e a segunda maior da Península Ibérica. Uma parte significativa resulta de sucessivas campanhas científicas para a recolha e o estudo de espécies vegetais em vários países africanos, que os documentários agora irão retratar.

Uma parte da história à volta destas campanhas estava de certa forma escondida do público em geral, em gabinetes e armários do antigo Departamento de Botânica. “Percebemos que havia uma riqueza documental enorme”, afirma Helena Freitas, directora do Jardim Botânico de Coimbra. Desde 2005, a documentação tem vindo a ser organizada e disponibilizada através de uma biblioteca digital.

A partir daí surgiu a ideia de mostrar, também numa série de documentários, a história das missões botânicas dos naturalistas de Coimbra. O projecto foi viabilizado por uma candidatura ao programa COMPETE do QREN, com um financiamento de cerca de 500 mil euros – 70% de Bruxelas e 30% do Estado, através do programa Ciência Viva.

As “viagens filosóficas” são o mote do primeiro documentário – uma espécie de enquadramento daquelas que foram as primeiras expedições de cunho estritamente científico, no século XVIII. Os outros serão filmados em três países diferentes – Angola, Moçambique e São Tomé e Príncipe.

Jorge Paiva irá conduzir as histórias, percorrendo parte dos trajectos que outros naturalistas de Coimbra fizeram no princípio do século – Júlio Henriques, em São Tomé, em 1903, e Luís Carrisso, nas décadas de 1920 e 1930. Paiva, ele próprio, participou de expedições a Moçambique, na década de 1960, que serão objecto de um dos documentários. “Estive lá oito meses, sempre a acampar, e fiz 33.000 quilómetros”, relembra. “Estive em zonas onde lá não voltou mais ninguém”, completa.

As filmagens começam em Setembro, em São Tomé, e os documentários deverão estar concluídos até ao final de 2013. Serão transmitidos pela RTP. “Pretendemos que não seja algo académico, mas alargado ao público”, explica o coordenador do projecto, António Gouveia, biólogo do Centro de Ecologia Funcional da Universidade de Coimbra.

O conteúdo científico será assegurado pela universidade, enquanto os documentários em si ficarão a cargo da produtora Terratreme, escolhida por concurso, entre oito concorrentes. Cinco realizadores diferentes estarão à frente dos filmes: Susana Nobre (“viagens filosóficas”); Luísa Homem e Tiago Hespanha (Moçambique); João Nicolau (S.Tomé e Príncipe); e André Godinho (Angola). “Não ser um mesmo realizador para toda a série traz mais riqueza ao projecto”, afirma o produtor João Matos, da Terratreme.

Os filmes procurarão complementar as informações sobre a flora e os ecossistemas com a sua interacção com as comunidades e as tradições locais. “São filmes de divulgação científica, mas há muitas formas de divulgar ciência”, diz João Matos.

O PÚBLICO vai acompanhar o projecto das missões botânicas em África com uma série de artigos de cunho histórico sobre as viagens – a primeira das quais está na edição deste sábado do jornal –, com reportagens in loco das filmagens, na sua edição impressa, e com outros conteúdos editoriais na sua edição online.

A partir deste sábado, também está disponível no PÚBLICO online um blogue do projecto, da responsabilidade da Universidade de Coimbra.

Autor: Ricardo Garcia
Fonte: Ecosfera – Público
Original: http://bit.ly/z2LDmB


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It looks more like squid than steak and because it lacks the fat and protein found in real cattle, does not taste like traditional beef. So why would anyone eat meat grown in a lab?


Artificial meat may sound weird, but it could help feed millions with minimal environmental impact. Credit: iStockphoto

Cultured or in-vitro meat may still be years away from our supermarkets, but scientists in The Netherlands say they will be able to grow a hamburger by the end of this year.

Professor Mark Post, who is refining the meat-making process at Maastricht University, says once perfected, the technology could slash the environmental footprint of growing food. He predicts in-vitro meat could reduce the requirement for livestock by a factor of one million.

Livestock for human consumption takes up 70 per cent of the world’s arable land. They use eight per cent of global freshwater and produce 18 per cent of all global greenhouse gas emissions – some 3,000 million tonnes of carbon dioxide emissions every year (that’s more than the entire world’s transport sector). Deforestation to create farmland accounts for a third of those emissions.

If the amount of meat we consume continues to increase at its current rate, the UN’s Food and Agriculture Organisation (FAO) predicts that it will double by 2050 and farmers will struggle to meet demand.

Professor Alan Bell, Chief of Livestock Industries at Australia’s national science agency, the CSIRO, says radical changes are needed to both agriculture industries and global eating habits.

“We have to become more efficient and make better use of waste resources or resources that are presently wasted,” he said.

“And as developing countries become more prosperous, those of us in the developed world will have to pay a lot more for our livestock products and maybe consume less.”

Research carried out by agro-ecologist Hanna Tuomisto at Oxford University’s Wildlife Conservation Research Unit in the UK suggests in-vitro meat may be able to meet demand while reducing environmental impact.

Comparing the life cycle of a piece of lab-grown meat with that of a cow, she concluded that it required up to 45 per cent less energy to produce and resulted in as little as 4 cent of the greenhouse gas emissions.

“In terms of environmental impact it would still be better being vegetarian but cultured meat would be much better than any kind of current meat production,” says Tuomisto.

“For example, the water requirement for [producing] cultured meat is just five per cent compared to conventionally produced beef.

“So, if we can produce meat in a lab which tastes good and is healthy, that would be a win-win situation – people won’t need to change their diets and it would be better for the environment.”

Growing beef in a machine would also reduce the need to convert land for farming and provide some protection for rare and endangered species that are currently overhunted for food. And, containing the process in a factory would enable better waste water management compared to run-offs from farmers’ fields.

There is also the potential for building burgers that are packed full of health-boosting vitamins and micronutrients such as iron, zinc, and calcium, but devoid of cholesterol-inducing fatty acids.

The concept of cultured meat is a hot topic among members of the UK-based Vegetarian Society for whom it may pose a cruelty free way of enjoying the taste of bacon.

“We voted against the motion ‘In vitro meat – is it the future of food?’ at the charity’s supporters conference in 2010, but not before hearing some strongly held views in favour,” said Su Taylor, a spokesperson for the organisation.

“Many campaigners argue that any development which results in fewer animals being reared and slaughtered for food is a good thing.”

Animal rights groups PETA and Voiceless share a similar view.

Sociologist Neil Stephenson, who has interviewed many of those developing cultured meat, says that even bioethicists exploring the issues around test tube burgers have struggled to find any robust objection.

“In terms of investing the money and pursuing the research, no one really gets hurt – it’s just scientists in their laboratories seeing if they can make it,” he said. “There are no clear reasons to stand against it.”

However, that doesn’t mean that people will want to eat it.

“The ethicists recognise the ‘yuck factor’ – the idea that when people hear about it they are disgusted by it,” adds Stephenson.

Similarly, Professor Post from Maastricht University hasn’t yet encountered any opposition to his work with in vitro meat but accepts that winning over consumers will be a challenge to overcome if his product is ever to be a success commercially.

And while research paints a green picture for the test tube burger, the industrial processes needed to mass-produce are yet undefined.

“Right now, a small number of people trying to make in-vitro meat won’t have significant environmental issues,” says Stephenson.

“In future if it’s going to be made in massive factories, with several plants in every country, there’s obviously going to be a lot more energy inputs that go into running them.”

Bioreactors might also come with a different set of problems to those associated with traditional livestock farming, says Stephenson.

“There might be planning issues, because potentially these could be very big things that look unattractive,” he explains.

“There are local environmental issues such as the impact upon traffic or the aesthetics of the area. In the overall story these are quite small things but they are imaginable.”

Another possibility is that like many scientific breakthroughs before it, the technology behind growing meat in a lab may find its primary use elsewhere.

“People in the [United] States are already considering using it to produce fish food -small quantities would change the texture and digestibility of other food stuffs,” said Stephenson.

“It never would have occurred to me that it could end up as an input to an industrial fish farm.

“That’s why it’s so hard to say now what the costs and benefits of this might be – in vitro meat technology might radically change some aspect of current practice that hasn’t yet occurred to us.”

Author: Sharon Kean
Source: ABC – Australian Broadcasting Corporation
Original: http://bit.ly/xZHH9E


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