A new study from American Cancer Society researchers finds it’s not just how much physical activity you get, but how much time you spend sitting that can affect your risk of death.
Researchers say time spent sitting was independently associated with total mortality, regardless of physical activity level. They conclude that public health messages should promote both being physically active and reducing time spent sitting. The study appears early online in the American Journal of Epidemiology.
To explore the association between sitting time and mortality, researchers examined the amount of time spent sitting and physical activity in relation to mortality between 1993 and 2006. They found that more leisure time spent sitting was associated with higher risk of mortality, particularly in women. Women who reported more than six hours per day of sitting were 37 percent more likely to die during the time period studied than those who sat fewer than 3 hours a day. Men who sat more than 6 hours a day were 18 percent more likely to die than those who sat fewer than 3 hours per day. The association remained virtually unchanged after adjusting for physical activity level. Associations were stronger for cardiovascular disease mortality than for cancer mortality.
When combined with a lack of physical activity, the association was even stronger. Women and men who both sat more and were less physically were 94% and 48% more likely, respectively, to die compared with those who reported sitting the least and being most active.
“Several factors could explain the positive association between time spent sitting and higher all-cause death rates,” said Dr. Patel. “Prolonged time spent sitting, independent of physical activity, has been shown to have important metabolic consequences, and may influence things like triglycerides, high density lipoprotein, cholesterol, fasting plasma glucose, resting blood pressure, and leptin, which are biomarkers of obesity and cardiovascular and other chronic diseases.”
Thursday, July 29, 2010
Less Than 1 Year Until The Internet Runs Out of Addresses
With a maximum of just over 4 billion unique addresses, the Internet will run out of Internet addresses in about 1 year’s time, due to an explosion of data about to happen to the Web — thanks largely to sensor data, smart grids, RFID and other Internet of Things data; the increase in mobile devices connecting to the Internet; and the annual growth in user-generated content on the Web.
The solution: IPv6, the next generation Internet Protocol, which uses a 128-bit address, vs. 32 bit with the current IPv4.
The solution: IPv6, the next generation Internet Protocol, which uses a 128-bit address, vs. 32 bit with the current IPv4.
Saturday, July 24, 2010
Chicken Came Before the Egg: "Scientific Proof"
British scientists claim to have solved one of the great mysteries of life, the universe and everything in it: The chicken came before the egg, they say, and they're not mincing words.
"It had long been suspected that the egg came first, but now we have the scientific proof that shows that in fact the chicken came first," Sheffield University's Dr Colin Freeman, according to a report in the Metro.
Researchers from Scotland and England used a supercomputer called HECToR to look in such detail at a chicken eggshell that they were able to determine the vital role of a protein used to kick-start the egg's formation.
That protein is only found, wait for it... inside a chicken.
Freeman, who worked on HECToR with counterparts at Edinburgh's Warwick University, said the protein had been identified earlier by scientists and was known to be linked to egg formation, "but by examining it closely we have been able to see how it controls the process," he added, describing it as a catalyst.
Professor John Harding, who also took part in the research, told Metro the discovery could have other applications.
"Understanding how chickens make shells is fascinating in itself, but can also give clues towards designing new materials." he said.
Which is good, because in spite of HECToR's hard work and the "scientific proof" it yielded, the study offered no explanation as to how the chicken got there in the first place.
If not from an egg, perhaps it just came from across the road.
"It had long been suspected that the egg came first, but now we have the scientific proof that shows that in fact the chicken came first," Sheffield University's Dr Colin Freeman, according to a report in the Metro.
Researchers from Scotland and England used a supercomputer called HECToR to look in such detail at a chicken eggshell that they were able to determine the vital role of a protein used to kick-start the egg's formation.
That protein is only found, wait for it... inside a chicken.
Freeman, who worked on HECToR with counterparts at Edinburgh's Warwick University, said the protein had been identified earlier by scientists and was known to be linked to egg formation, "but by examining it closely we have been able to see how it controls the process," he added, describing it as a catalyst.
Professor John Harding, who also took part in the research, told Metro the discovery could have other applications.
"Understanding how chickens make shells is fascinating in itself, but can also give clues towards designing new materials." he said.
Which is good, because in spite of HECToR's hard work and the "scientific proof" it yielded, the study offered no explanation as to how the chicken got there in the first place.
If not from an egg, perhaps it just came from across the road.
India develops 35-dollar 'laptop' for schools
India has come up with a 35-dollar touch-screen "laptop" -- a computing prototype that it aims to make available to students from elementary schools to universities.
The gadget, developed by the elite Indian Institute of Technology and the Indian Institute of Science, is part of a push to give students a better education and technical skills needed to boost India's economic growth.
The first users are expected to be university students with introduction of the Linux-based computing device targeted for next year.
The ministry is going to install broadband Internet at all of its 22,000 colleges so students can use the 1,500-rupee (35-dollar) device, government spokeswoman Mamta Verma told AFP on Friday in New Delhi.
The tablet gadget, which can be run on solar power, is equipped with an Internet browser, video-conferencing capability and a media player, among other facilities.
"This is part of the national initiative to take forward inclusive education," Human Resource Development Minister Kapil Sibal told reporters on Thursday.
"The solutions for tomorrow will emerge from India," he said.
Sibal said the cost of the motherboard, chip, processing and other components cost a total of around 35 dollars but the government may subsidise 50 percent of the price for students.
Sibal said the government, which hopes the cost of the device can eventually fall to 10 dollars, is in discussions with global manufacturers to start mass production of the device.
India, whose 63 percent literacy rate lags far behind many other developing nations, such as China with 94 percent, is making efforts to improve its troubled education system, which lacks investment in schools and teachers.
The gadget, developed by the elite Indian Institute of Technology and the Indian Institute of Science, is part of a push to give students a better education and technical skills needed to boost India's economic growth.
The first users are expected to be university students with introduction of the Linux-based computing device targeted for next year.
The ministry is going to install broadband Internet at all of its 22,000 colleges so students can use the 1,500-rupee (35-dollar) device, government spokeswoman Mamta Verma told AFP on Friday in New Delhi.
The tablet gadget, which can be run on solar power, is equipped with an Internet browser, video-conferencing capability and a media player, among other facilities.
"This is part of the national initiative to take forward inclusive education," Human Resource Development Minister Kapil Sibal told reporters on Thursday.
"The solutions for tomorrow will emerge from India," he said.
Sibal said the cost of the motherboard, chip, processing and other components cost a total of around 35 dollars but the government may subsidise 50 percent of the price for students.
Sibal said the government, which hopes the cost of the device can eventually fall to 10 dollars, is in discussions with global manufacturers to start mass production of the device.
India, whose 63 percent literacy rate lags far behind many other developing nations, such as China with 94 percent, is making efforts to improve its troubled education system, which lacks investment in schools and teachers.
Thursday, April 8, 2010
Friday, March 26, 2010
Why HOT water freezes quicker than COLD water
HOT water sometimes freezes faster than cold water - but why? This peculiar phenomenon has baffled scientists for generations, but now there is evidence that the effect may depend on random impurities in the water.
Fast-freezing of hot water is known as the Mpemba effect, after a Tanzanian schoolboy called Erasto Mpemba (see "How the Mpemba effect got its name"). Physicists have come up with several possible explanations, including faster evaporation reducing the volume of hot water, a layer of frost insulating the cooler water, and differing concentration of solutes. But the answer has been very hard to pin down because the effect is unreliable - cold water is just as likely to freeze faster.
James Brownridge, who is radiation safety officer for the State University of New York at Binghamton, believes that this randomness is crucial. Over the past 10 years he has carried out hundreds of experiments on the Mpemba effect in his spare time, and has evidence that the effect is based on the shifty phenomenon of supercooling.
"Water hardly ever freezes at 0 °C," says Brownridge. "It usually supercools, and only begins freezing at a lower temperature." The freezing point depends on impurities in the water which seed the formation of ice crystals. Typically, water may contain several types of impurity, from dust particles to dissolved salts and bacteria, each of which triggers freezing at a characteristic temperature. The impurity with the highest nucleation temperature determines the temperature at which the water freezes.
Brownridge starts with two samples of water at the same temperature - say, tap water at 20 °C - in covered test tubes and cools them in a freezer. One will freeze first, presumably because its random mix of impurities give it a higher freezing point.
If the difference is large enough, the Mpemba effect will appear. Brownridge selects the sample with the higher natural freezing temperature to heat to 80 °C, warming the other to only room temperature, then puts the test tubes back in the freezer. The hot water will always freeze faster than the cold water if its freezing point is at least 5 °C higher, Brownridge says.
It may seem surprising that moving the finish line by only 5 °C makes enough of a difference, when the hotter sample starts out 60 °C behind in the race. But the bigger the temperature difference between an object and its surroundings - in this case, the freezer - the faster it cools. So the hot sample will do most of its cooling very quickly, helping it to reach its own freezing point of -2 °C, say, before the cooler water gets to its freezing point of -7 °C.
Fast-freezing of hot water is known as the Mpemba effect, after a Tanzanian schoolboy called Erasto Mpemba (see "How the Mpemba effect got its name"). Physicists have come up with several possible explanations, including faster evaporation reducing the volume of hot water, a layer of frost insulating the cooler water, and differing concentration of solutes. But the answer has been very hard to pin down because the effect is unreliable - cold water is just as likely to freeze faster.
James Brownridge, who is radiation safety officer for the State University of New York at Binghamton, believes that this randomness is crucial. Over the past 10 years he has carried out hundreds of experiments on the Mpemba effect in his spare time, and has evidence that the effect is based on the shifty phenomenon of supercooling.
"Water hardly ever freezes at 0 °C," says Brownridge. "It usually supercools, and only begins freezing at a lower temperature." The freezing point depends on impurities in the water which seed the formation of ice crystals. Typically, water may contain several types of impurity, from dust particles to dissolved salts and bacteria, each of which triggers freezing at a characteristic temperature. The impurity with the highest nucleation temperature determines the temperature at which the water freezes.
Brownridge starts with two samples of water at the same temperature - say, tap water at 20 °C - in covered test tubes and cools them in a freezer. One will freeze first, presumably because its random mix of impurities give it a higher freezing point.
If the difference is large enough, the Mpemba effect will appear. Brownridge selects the sample with the higher natural freezing temperature to heat to 80 °C, warming the other to only room temperature, then puts the test tubes back in the freezer. The hot water will always freeze faster than the cold water if its freezing point is at least 5 °C higher, Brownridge says.
It may seem surprising that moving the finish line by only 5 °C makes enough of a difference, when the hotter sample starts out 60 °C behind in the race. But the bigger the temperature difference between an object and its surroundings - in this case, the freezer - the faster it cools. So the hot sample will do most of its cooling very quickly, helping it to reach its own freezing point of -2 °C, say, before the cooler water gets to its freezing point of -7 °C.
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