The Women's Health Initiative is a clinical trial sponsored by the National Heart, Lung, and Blood Institute, an institute of the National Institutes of Health. It included the largest ever study of a low-fat diet in postmenopausal women to see if such a diet reduced their rate of contracting certain diseases. 48,835 women aged 50-79 participated for an average of 8 years. The results of the low-fat diet trial showed no significant reduction in the rate of breast cancer, heart disease, or stroke and no effect on the risk of colorectal cancer. However, the women in the study had trouble sticking to the recommended amount of daily fat and they did not necessarily cut out the types of fat considered most harmful (saturated fats and trans fats).
What About Nutritional Supplements?
The study also followed 36,282 women of the same age range to find out if calcium and vitamin D supplements reduced the rate of broken bones from osteoporosis. Again the results appeared to show no appreciable advantage to taking the supplements, although there was an average of 1% gain in bone density.
Drop the Supplements and Forget the Low-Fat Diet?
Researchers found that the trend in positive results was going upwards for the group on the low fat diet enough to encourage the researchers that continued monitoring of the women over the next few years will show a positive result. And people connected with the calcium/vitamin D supplement study say that despite the slightly elevated risk of kidney stones that was seen in some women, the overall gain in bone density was great enough to make a difference for some women and to have a positive impact on money spent on health care for osteoporosis-related injuries.
The upshot is that there are still opportunities to learn more information about how diet and supplements affect the health of these postmenopausal women, including why some subgroups of women were affected in ways that others weren't. Doctors and researchers aren't changing their overall advice yet, although people should always discuss their diets with their doctors as cases can differ from person to person.
What goals did early science museums set out to accomplish? And how do those same priorities relate to us today? A new series of articles published by the History of Science Society shows the important role science museums have played in North America and Europe over the past two centuries, and some of the challenges that museums have faced.
The Science Museum's neighbor, the Xcel Energy High Bridge power plant, will be undergoing a significant construction project in the coming months. As part of a larger project called Metro Emissions Reduction Project (MERP) Xcel Energy has started working on a $1 billion program that will reduce emissions from three metro area plants (the High Bridge Plant being one) and increase power generating capacity.
The High Bridge power plant is being converted from a coal burning plant to a combined-cycle natural gas plant. Combined power plants generate electricity from two sources - a gas turbine generator that is powered by natural gas and a steam turbine generator that is powered by the heat exhaust from the gas turbine generator. This use of the gas to essentially power two different types of generators is a more efficient use of resources than the coal burning power plant. As a result of this change, air emissions from the High Bridge power plant will be significantly reduced. Sulfur dioxide emissions will be reduced 99.7%, nitrogen oxide 96.9% and particulate matter 91.5%, while mercury pollution will be completely eliminated.
My first thought after hearing this (and after having to put gas in my car and heat my home the past few months) was that switching to natural gas is not a very economical situation given current gas prices. However, Xcel says that:
Although natural gas prices have increased, this conversion makes sense for the long term. The gas market is subject to short-term volatility, but the plants will operate for another 30 years so it's the long-term projections that are most important.
If you are in the downtown area in the coming weeks you may hear construction noise from the site as the nearly 1,200 steel pilings for the new power plant are driven into the ground for the new plant's footings. Testing of the new power plant will begin around September 2007 and run through March 2008. The plant is expected to begin commercial operation in May 2008, and demolition of the old plant will start shortly thereafter.
For more information visit Xcel Energy's web pages on the conversion.
Minnesota's warmest January on record was good for starting cars, easing our heating bills, and waiting at bus stops. But what impact will it have on Minnesota's wildlife?
A few weeks ago, City Pages posed that question to Minnesota Department of Natural Resources officials, who said that our freaky weather creates definite winners and losers.
Two fascinating stories related to the archaeology of Great Britain and the monetary (dollar) value of significant archaeological finds appeared in the news this week. The first story is related to an archaeological find in Lancaster, and the second is related to an Anglo-Saxon coin which was owned by a man right here in Minnesota.
Most professional archaeologists think of their finds as priceless. An archaeologist is concerned with what their finds can contribute to science, history and maybe future museum displays. While it used to be much more common for archaeological finds to come up for sale in public auction, the importance of an artifacts original context has grown ever more important in modern archaeology, making single artifacts not associated with a known archaeological site far-less desirable. While artifacts are sometimes given a monetary value by an insurance company before it goes on loan to another museum - most professionally acquired artifacts never appear at auction.
The news of the find of a Roman gravestone with a clear etching of a solider caused excitement among archaeologists in Great Britain. Archaeologists were excited by the find because it is in such great condition. Those same archaeologists, however, were saddened by the fact that the developer, who owned the land where the artifact was found, had already spoken to Sotheby's, the famous auction house. It is expected to bring about $100,000 (£357,500) at auction.
The second news story appeared in the StarTribune. The story begins, "For a little more than a year, it was his: a small gold coin 1,200 years old and bearing the likeness of Coenwulf, king of the Anglo-Saxon settlement of Mercia, and the first-known coin reference to a marketplace named London." Allan Davisson, the now former-owner of the coin mortgaged his home to pay for the $400,000 bill for the artifact. Davisson recently sold the coin for a considerable profit to an American collector who was willing to pay $600,000 for the specimen. The new owner plans to sell it to the British Museum in London. The article continues, "It is the first gold coin in Great Britain to bear the image of a monarch and the first to include, on the obverse side, a reference -- in Latin -- to London. British authorities say it may be the most important coin in the realm for its numismatic, historical and cultural value."
The study of numismatics, or money in all its forms, is popular among both professional archaeologists and amateurs. Many types of historic coins are viewed as being valuable because they provide so much information for their context right on the coin itself. The image of an important individual can date a coin to within a few years, and a written description can tell numismatists where the coin was minted, or produced. An early reference to the city of London, like in the coin discussed above makes an artifact like this virtually priceless. Sometimes, however, museums and auction houses alike are asked to put a price on the priceless.
What type of questions do sales like the ones described above bring up for archaeology?
If you were in charge of making laws governing antiquties, like priceless archaeological artifacts, what sort of rules would you make surrounding their sale or removal from their country of origin?
Do you think it should be illegal for certain types of artifacts to be owned by private collectors, rather than museums? Why or why not?
Should certain artifacts, or types of artifacts, that have already been removed from their country of origin be returned, or is it "finders keepers"?
For additional information on the coin described in the StarTribune check out the Santa Clara History in pictures website.
Mexican wolves are the smallest subspecies of the gray wolf, and one of the most endangered mammals on Earth. At one time the Mexican wolf roamed over a large area of the southwestern United States and parts of central Mexico. Between 1870 and 1970 the Mexican wolf population was brought to the brink of extinction. The Mexican wolf was placed on the Endangered Species List in 1976. Between 1977 and 1980 the United States and Mexico joined efforts to capture 5 Mexican Wolves for a breeding program. These original 5 wolves along with new wolves added in 1995 make up the captive population of about 280 Mexican wolves.
The Minnesota Zoological Gardens in Apple Valley Minnesota is active in the preservation of this highly endangered species. In 1994 the United States Fish and Wildlife Service approached the MN Zoo to join efforts in the Mexican Wolf Conservation and Restoration Project. Currently 4 male Mexican wolves call Minnesota home.
Even though people often think of the southwest as a very hot climate, there are areas of New Mexica and Arizona that get cold. Our pack of Mexican wolves do very well in the Minnesota climate... The wolves deal with our climate by growing a nice, warm coat and don't need anything else from us.
- Jackie Fallon, Zoologist, Minnesota Zoological Gardens.
You are reading this alternate content because you do not have Flash 6 installed.
To see the visuals install/update your plugin.
Click here if you beleive you are seeing this message in error.
A bowling ball swings from a great height into a pane of glass but it doesn't break.
When the Strange Matter exhibit opened here at the Science Museum on Feb. 4, the large pane of glass in the "Smash the Glass" activity already had been hit about 137,500 times ... by a swinging bowling ball. Since then, museum visitors have swung the bowling ball against the glass 10,000 times, putting the total number of hits above 147,500 on Feb. 19.
How many more hits can the glass resist? Well, it took about 157,000 strikes before a pane of glass broke last time (when Strange Matter was at another museum). At that rate, the glass might shatter at the Science Museum in early March. But the glass could break even sooner than that. We'll just have to wait and see.
U.S. and Canadian slalom skiers are wearing lightweight, flexible protective gear made from a new material (d3o) that hardens into armor when it's crashed into.
Normally, skiers wear hard arm and leg guards to protect themselves from poles along the slalom run. But the Colorado-based skiwear company Spyder created racing suits with d3o along the shins and forearms, and the suits caught on.
The exact chemical composition of d3o is a trade secret, but it's made by combining a viscose fluid and a polymer, then pouring the liquid d3o into a mold that matches the shape of the body part needing protection.
According to a New Scientist article,
"The resulting material exhibits a material property called 'strain rate sensitivity'. Under normal conditions the molecules within the material are weakly bound and can move past each with ease, making the material flexible. But the shock of sudden deformation causes the chemical bonds to strengthen and the moving molecules to lock, turning the material into a more solid, protective shield.
That's the promise of a new battery developed by researchers at MIT's Laboratory for Electromagnetic and Electronic Systems. They're using nanotechnology to improve an energy storage device called an ultracapacitor.
Unlike regular batteries, which can generate electricity from a chemical reaction, capacitors store energy as an electrical field. Ultracapacitors can store lots of energy for a long time, but they need to be much bigger than regular batteries to hold the same amount of electricity. The new MIT technique, uses nanotechnology to improve the storage capacity of existing capacitors and may eventually help to make them smaller.
A battery has two electrodes, or terminals, one positive and one negative. Inside the battery are chemicals that react with each other to produce electrons. The electrons collect on the negative terminal of the battery. When you connect the terminals with a wire, you can use the flow of electrons to power things. A capacitor also has two electrodes-metal plates separated by a material that doesn't conduct electricity. A positive charge builds up on one plate, and a negative charge builds up on the other. When you connect the two electrodes, they discharge their energy. A battery can actually "create" energy by changing chemicals into electricity while a capacitor can only store energy it has been charged with.
Today's ultracapacitors use electrodes made of activated carbon; the carbon is porous, so it has lots of surface area for the electrons to build up on. But the pores are irregular in size and shape, which reduces efficiency. That's why capacitors have to be big. But the MIT ultracapacitor has electrodes of vertically aligned carbon nanotubes, each one thirty-thousandth the width of a human hair. The regular shape and alignment of the nanotubes greatly increases the surface area, making the ultracapacitor very efficient at storing electrons.
Ultracapacitors are long lasting and quick-charging. Storing energy at the atomic level with nanotubes means that they can finally be small, too, perhaps eventually powering everything from flashlights and cell phones to hybrid cars and missile-guidance systems.
Stop by the Museum on Saturday, February 18th. You can make a pop can flashlight and test some conventional batteries. Experiment with electricity, circuits, and capacitors more at the AC/DC electricity bench in the Experiment Gallery.
A new study suggests that our brains learn by replaying events in reverse.
In a lab experiment, mice were taught a new task. Researchers recorded their brain activity. After the task, they found the nerve cells active in learning the task fired again, but in reverse order. Scientists suspect the brain is trying to reinforce the activities closest to the successful completion of the task.
Human brains and rat brains have some strong similarities, so this may lead to a new understanding of human learning. For instance, researchers have long known that cramming right before a test generally doesn't help—the brain needs time to absorb the new knowledge. If the "running in reverse" pattern holds true in humans, then the best approach may be to take frequent breaks to allow our brains to review the material.
Hmm, I wonder if my boss will buy that? "I wasn't goofing off playing Solitaire! I was giving my brain a chance to replay my new knowledge!"