They found that male smokers exhibited faster mental decline

Smoking is known to be a risk factor for dementia in the aged, but the extent to which it is a risk factor for cognitive problems earlier in life is less-well understood, wrote the team.Gucci outlet online shop provides gucci 2012 new arrivals, up to 70% off. Welcome to buy cheap gucci items for men and women, all are latest styles in various colors for your choice.

Led by Severine Sabia of University College London's Department of Epidemiology and Public Health, the researchers looked at data collected from 5,099 men and 2,137 women. The subjects were employees of the British Civil Service who had participated in the Whitehall II study, which launched in 1985 and which conducted its ninth phase from 2007 to 2009.

To assess the relationship between subjects' smoking history and their level of cognitive decline, Sabia and her colleagues reviewed six self-reported assessments of smoking status collected over a period of 25 years, and three assessments of cognitive function collected over a period of 10 years. The cognitive tests were administered when participants were 44-69 years old, 50-74 years old and 55-80 years old.

They found that male smokers exhibited faster mental decline than non-smokers -- and the decline was more pronounced the more cigarettes a subject smoked.

"The effect size associated with smoking is similar to that associated with 10 years of age," they wrote.

Smokers who had quit at least 10 years before the first assessment did not show a significant speed-up in cognitive decline. Neither did women -- perhaps, the authors wrote, because the men in the study smoked more than the women did. They also hypothesized that it could be because smoking was associated with other risk factors in men, such as greater alcohol consumption.

The team wrote that it was not sure of the mechanism behind smokers' rapid mental decline, suggesting that it could stem from vascular or lung damage.

"It is increasingly recognized that age-related cognitive pathologies such as dementia result from long-term processes, perhaps beginning as long as 20 to 30 years before the clinical diagnosis of dementia. Our study illustrates the importance of examining risk factors for cognitive decline much earlier in the life course," the coauthors concluded.

This is according to scientists who have reconstructed the song of a cricket that chirped 165 million years ago.

A remarkably complete fossil of the prehistoric insect enabled the team to see the structures in its wings that rubbed together to make the sound.

The international team report their findings in the journal PNAS.

Scientists from the US and China discovered the cheapguccioutlet2012.com tiny fossil and named their newly discovered species Archaboilus musicus , because the music-making structures in its body were so clearly visible.

When insect expert Dr Fernando Montealegre Zapata, from the University of Bristol, found out that his colleagues had such a remarkable fossil, he was keen to see it.

"I was very surprised," he told BBC Nature, "because those [structures] are very very small - at the microscopic level."

Dr Zapata studies sound production and communication in living insects, working out how the musical instruments contained in many insects' bodies produce a particular sound, and exactly how that sound is made.

Just like modern bush crickets - also known as katydids - the Jurassic insects produced music with their wings. A "plectrum" on one wing was dragged along a microscopic comb-like structure on the other.

This produces a continuous "chirp" as the male insects rub, or "stridulate" their wings in a scissor-like motion. Dr Zapata described this stridulation as similar to playing a tiny violin.

By looking at the wing structures, he explained, "I could estimate that the animal made pure, musical tones".

Such a single-note tone would have transmitted efficiently - a regular wave of sound penetrating a noisy environment cluttered with vegetation. This would have allowed a female cricket to detect a male's song from tens of metres away.

Dr Zapata then set out to calculate the frequency of the tone, which denotes how high- or low-pitched it sounded. To to this, he simply compared the size and shape of its music-making or "stridulatory" instruments to those of living cricket species.

"I produced a graph of [living] species, plotting the measurements of their sound-making structures against the frequency of the sound they made," he explained.

"Using the measurements, I could plot this extinct species onto that graph."

He discovered that A. musicus used a relatively low-pitched song, compared with modern bush crickets.

This suggested that the Jurassic forest was a cluttered and "noisy environment - especially at night", he said.

"There were probably frogs, other [insects] and sounds from the water," he said.

Being noctural, A. musicus would not have had to hide its musical call from predators that were active during the day, including the famous Jurassic bird, Archaeopteryx.

The crickets may have been hunted by early mammals. But bats - many of which feast on nocturnal insects - did not appear until about 100 million years later.

"That's when the modern katydids became ultrasonic," said Dr Zapata.

The researcher emphasised how lucky he and his team were to find this extraordinary fossil.

"This animal allows us to build a picture of the ecology of the Jurassic forest," he said, "and will give hints as to how other animals were singing at the time."

Prof Mike Ritchie from the University of St Andrews said it was surprising that "way back in early cricket time, they were already producing these very musical calls".Gucci watches on sale, buy cheap gucci watches 2012, 70% off.

"People thought singing in crickets probably evolved later from a startle reflex," he told BBC Nature.

"But this suggests that [very early on] they were already... producing these lovely, pure tones to compete for a mate.