Nuclear subs collide in Atlantic

A Royal Navy nuclear submarine was involved in a collision with a French nuclear sub in the middle of the Atlantic, the MoD has confirmed.

HMS Vanguard and Le Triomphant were badly damaged in the crash in heavy seas earlier this month.

First Sea Lord Admiral Sir Jonathon Band said the submarines came into contact at low speed and no injuries were reported.

Both the UK and France insisted nuclear security had not been compromised.

Taiwan President Ma Ying-jeou has met China's senior envoy to the island in the highest level contact since 1949.

The meeting was brought forward five hours to avoid continuing protests by Taiwanese pro-independence groups.

Mr Ma defended his agreements with Beijing, saying they did not damage Taiwan's sovereignty.

The Chinese envoy, Chen Yunlin, has signed economic agreements with Taiwan but has also been trapped in a hotel by Taiwan pro-independence protesters.

Mr Chen's meeting with Mr Ma at a government guest house lasted just five minutes and involved the exchange of gifts - a vase from Mr Ma and a large scroll painting of a horse from Mr Chen.

Increased rainfall, or something linked to it, may be connected to the development of autism, scientists say.

The theory is based on child health and weather records from three US states, but has been greeted cautiously by a UK research charity.

The US study found autism rates were higher among children whose states experienced higher rainfall in their first three years.

The work appears in Archives of Pediatrics and Adolescent Medicine.

The rising rate of autism - up, by some measures, from one in 2,500 to one in 150 - has been attributed mainly to improvements in the way doctors are able to recognise the disorder.

In gadget-crazy Japan, Sony president Ryoji Chubachi is somewhat of an aristocrat.

At a recent press briefing in Tokyo, he is met by a crowd of more than 50 journalists. They hang on his every word.

"Thank you for coming," he greets them, as he steps up next to one of firm's new super thin televisions.

"Amazing technology isn't it," he says with obvious pride.

Lost lead

The thickness of Arctic sea ice "plummeted" last winter, thinning by as much as 49 centimetres (1.6ft) in some regions, satellite data has revealed.

A study by UK researchers showed that the ice thickness had been fairly constant for the previous five winters.

The team from University College London added that the results provided the first definitive proof that the overall volume of Arctic ice was decreasing.

The findings have been published in the journal Geophysical Research Letters.

"The ice thickness was fairly constant for the five winters before this, but it plummeted in the winter after the 2007 minimum," lead author Katharine Giles told BBC News.

One of Europe's flagship space projects looks as though it is going to proceed with the UK continuing to be a bit-part player, scientists and engineers fear.

The Kopernikus programme is dedicated to acquiring and collating satellite data on the health of the planet.

Although Britain says it recognises the project's high value, especially for monitoring the climate, it has so far declined to take a lead in the venture.

Industry and academia have called for a swift change in government policy.

Failure to adopt a more positive approach before a critical meeting of Europe's space ministers next month will put expertise and jobs in the UK at risk, they warn.

US Defence Secretary Robert Gates has warned of "dramatic consequences" if Washington and Baghdad do not agree a security deal on US forces in Iraq.

He said if there were no Status of Forces Agreement the US would have to "basically stop doing anything".

Iraq's cabinet is demanding changes to a draft deal already agreed with Washington that would allow US forces to stay in Iraq until 2011.

Mr Gates said the US had "great reluctance" to renegotiate.

"I don't think you slam the door shut, but I would say it's pretty far closed," he said.

"If the US economy catches a cold, Mexico catches pneumonia," the saying goes. Money sent from the US by Mexican workers there rank as the country's second largest source of foreign income. But that money has dropped 12%, the Central Bank says, due to a recession in the US construction industry, a heavy user of Mexican labour. Tighter border controls and a US crackdown on illegal immigration have also played a role.

Despite these concerns, Mexico's President Felipe Calderon is confident that the country will not suffer the ramifications of the credit crunch, and has proposed to spend US$4.4 billion next year (£2.5bn; 3.3bn euros) on infrastructure projects.

The labour secretary for the Mexico City government, Benito Miron Lince, has announced plans to support some 30,000 workers who are expected to return to the Mexican capital because of the slowdown in the US. Officials have stated that the current unemployment insurance program, unveiled last autumn, will be broadened. According to Mr Miron Lince, demand for unemployment benefits has rapidly increased during the last few months.

With the wave of migrants heading back, it is becoming increasingly evident that re-adjusting to a country that was once their home is not that simple.

After spending most of their lives in the US, Mexican families barely recognise relatives or their towns. Children in particular are often mocked and discriminated against by their teachers and fellow students when they pronounce their names in an American accent. Many are returning to the same grinding poverty that originally drove them out.

Controlling the level of a fatty acid in the brain could help treat Alzheimer's disease, an American study has suggested.

Tests on mice showed that reducing excess levels of the acid lessened animals' memory problems and behavioural changes.

Writing in Nature Neuroscience, the team said fatty acid levels could be controlled through diet or drugs.

A UK Alzheimer's expert called the work "robust and exciting".

There are currently 700,000 people living with dementia in the UK, but that number is forecast to double within a generation.

US defence chief Robert Gates is seeking support from politicians on a draft deal to extend the US mandate in Iraq, which expires later this year.

Details have not been released, but officials say it would see US troops withdraw from Iraq by the end of 2011.

Mr Gates is said to be briefing key members of Congress on the deal, although their approval is not needed.

But the draft does need approval on the Iraqi side, which correspondents say could prove difficult.

The current UN mandate for US-led coalition forces in Iraq expires on 31 December. About 144,000 of the 152,000 foreign troops deployed there are US military personnel.