Women need more sleep than men - around 20 minutes of more sleep on an average - owing to their busy and multi-tasking brain, according to a new research by a British sleep expert.

"Women need 20 minutes more shut-eye than the average man. This is because women's brains are wired differently from men's and are more complex, so their sleep need is slightly greater," said Professor Jim Horne, director of the Sleep Research Centre at Loughborough University in UK.

Pointing out that one of the major functions of sleep is to allow the brain to recover and repair itself, Horne said, "During deep sleep, the cortex - part of the brain responsible for thought memory, language and so on - disengages from the senses and goes into recovery mode. The more a person uses his brain during the day, the more sleep he needs at night to recover, Horne said adding, "Women tend to multi-task - they do lots at once and are flexible - and so they use more of their actual brain than men do. Because of that, their sleep need is greater."

"A man who has a complex job that involves a lot of decision-making and lateral thinking may also need more sleep than the average male - though probably still not as much as a woman," he told.

Scientists have found evidence suggesting that blueberries may help improve memory in older adults because of its antioxidative phytochemicals, according to a new study published in the Journal of Agricultural and Food Chemistry.

Previous animal studies have suggested that eating blueberries may boost memory in older people, according to Robert Krikorian, author of the current study; he and colleagues from the University of Cincinnati worked in conjunction with several other organizations on the research.

Krikorian and colleagues tested the effect of blueberry juice on memory in a group of volunteers in their 70s with early memory decline. In the study, the study group drank 2 to 2.5 cups of blueberry juice while the control group drank a beverage every day for two months.

Those who drank blueberry juice experienced signficant improvement on learning and memory tests, according to the scientists.

"These preliminary memory findings are encouraging and suggest that consistent supplementation with blueberries may offer an approach to forestall or mitigate neurodegeneration," the authors wrote in the report.

Blueberries may also be helpful in encouraging weight loss and preventing type 1 diabetes according to previous studies.

Bird flu in West Bengal spread to two more localities in Murshidabad district, health authorities here said Friday after over 52,500 birds were culled in the affected areas.

'Two more epicenters surfaced in the Khargram block,' a health ministry official said.

Earlier, the outbreak of the flu was reported in Hazrabati and Nagar villages in Murshidabad Jan 14 and in Faridpur village of Burwan block Jan 17.

'Containment measures have been initiated as per the contingency plan and culling of birds has started. So far 52,578 birds have been culled and 4,572 eggs have been destroyed,' the official added.

Officials also said that 301 poultry workers and veterinary surgeons involved in culling operations have been put on chemoprophylaxis.

The surveillance activities are going on.

A "ubiquitous" chemical widely used in the manufacture of non-stick frying pans is linked to thyroid disease, researchers say.

A study involving almost 4,000 people in the United States found people that those with the highest levels of man-made perfluorooctanoic acid - also known as PFOA - in their blood were twice as likely to be diagnosed with thyroid disease or taking medication compared with those with the lowest levels.

PFOA is widely used in industry because it excels at repelling heat, water, grease and stains, and traces of the chemical are found in water, air and soil throughout the world.

But the researchers from the University of Exeter, who carried out the latest study, stressed that further research was needed to establish whether the chemical was a direct cause of illness in humans.

Previous studies in animals have suggested that high exposure to the chemical can affect the action of the thyroid gland, located in the neck, which is responsible for controlling the body's rate of metabolism through the release of hormones.

Tamara Galloway, Professor of Ecotoxicology at Exeter, said that it was likely that the chemical could be ingested or inhaled from the air or as a component of household dust, and might stay in the bloodstream for about five days.

Her team analysed an American database of 3,966 adults aged 20 and older, because no figures for blood levels of PFOA is available in Britain. Of these, 163 women and 46 men reported having current thyroid disease and were taking medication.

But a total of 16 per cent of women with the highest blood levels of the chemical (above 5.7ng/ml) reported having thyroid disease or were taking related medication, compared to 8 per cent of those with the lowest levels. the trend was similar in men, but not said to be statistically significant because of the low numbers of individuals involved.

"Our results highlight a real need for further research into the human health effects of low-level exposures to environmental chemicals like PFOA that are ubiquitous in the environment and in people's homes. We need to know what they are doing," Professor Galloway said.

But Diane Benford, Head of Toxicology of Food, Food Standards Agency, commented: "This type of study investigates associations and cannot establish causality. It is important to look at the consistency of the data with the results of other studies, and with what is known about the toxicity of PFOA and PFOS, which differ.

"Studies of workers with higher exposure to these compounds have not shown consistent evidence of increased risk of thyroid disease, which would be expected if effects are occurring in the general population. More research is needed to establish whether this association is causal."

Ashley Grossman, Professor of Neuroendocrinology, at Queen Mary, University of London, said that it was also unknown how PFOA might affect the thyroid gland.

"Thyroid disease is often caused by the body's own immune system attacking the thyroid gland so perhaps this chemical is having some effect on the immune system, rather than directly on the thyroid," he said.

"We'd need to do a lot more research to verify this link and to understand how the two are linked. In the meantime, it's important to remember that thyroid disease can be successfully treated."

Breast cancer screening may not be appropriate for all women, warned the experts from the University of Michigan. A genetic mutation that plays a significant role in increasing a woman's risk of developing breast cancer and ovarian cancer has been discovered.

Breast cancer, estimated to increase by 3 percent per annum up to 2015 in India, result from genetic abnormalities. However, only five to ten percent of the cases are due to inherited genetic factors, mostly due to abnormalities in two genes, BRCA1 and BRCA2. These two genes may be inherited from either of the parents and may pose a higher lifetime risk of developing breast and ovarian cancer, more likely to develop at an earlier stage.

Lifetime risk of breast cancer in these women jumps from 12.5 percent in the general population to approximately 60 percent in women with BRCA mutations. It should also be kept in mind that occurance of most of breast and ovarian cancers are random and may not be due to BRCA gene inheritence.

According to Dr Sofia Merajver, director of the Breast and Ovarian Risk Evaluation Program at the University of Michigan Comprehensive Cancer Centre, it is important that the right women seek out genetic testing for breast and ovarian cancer.

Though it is a simple blood test, the interpretation of the results may be complicated. Doctors recommend genetic testing for those with family history of cancer cases and diagnoses through several generations, older family members (above 50) diagnosed with cancer, family member with cases of multiple cancers like breast and ovarian and also male breast cancer, or other cancers like colon, stomach or prostrate cancers.

Undergoing genetic tests can help assess the risk factor of the person diagnosed with cancer.