By RANDOLPH E. SCHMID, AP Science Writer
Thu Apr 9, 5:21 pm ET
WASHINGTON – For millennia, people have watched the birds and bees and wondered: "How do they do that?" Thanks to high-speed film and some persistent scientists, at least one of the secrets of flight is now revealed. When birds, bats or bugs make a turn, all they have to do is start flapping their wings normally again and they straighten right out.
That came as a surprise to researchers who thought turning and stopping took more steps.
Lead researcher Tyson L. Hedrick of the University of North Carolina compared it to sitting at a desk chair and turning left. It's a three-step process, launch the turn by pushing with one foot, turn, then stop by pushing with the other.
It's a simpler, one-step process for flying animals, he explained in a telephone interview, launch a turn and then simply flap normally to end it and fly away.
The findings are reported in Friday's edition of the journal Science.
"We didn't expect things to fall out this neatly," he said, particularly since the process is the same for animals of all sizes from the fruit fly to the bat to the cockatoo.
"It's sort of unusual" to find a general rule to cover six orders of magnitude in size, he said.
The findings should help in the development of robotic flying machines, he said.
But, of course, this study focuses only on one type of maneuver, turning left or right, which is known as yaw in aviation.
There's still pitch — nose up or nose down — and roll, which is tilting left or right, to be dealt with.
"We picked basically the simplest turn you can imagine to make comparison," Hedrick said.
The situation does become more complicated with more complex maneuvers, "and that is clearly the next step," he said.
The report was welcomed by Bret W. Tobalske of the University of Montana, who said "the results will inform all future research into maneuvering flight in animals and biomimetic flying robots."
"Now that technology has developed to the point where detailed measurements of flapping maneuvers have become feasible, a world of comparative research is opening," Tobalske, who was not part of the research team, said in a commentary on the paper.
The research was funded by the National Science Foundation.
Thursday, April 9, 2009
Scientists start to unlock secrets of bird flight
Monday, March 16, 2009
How to tell, what to do if computer is infected
Posted on Sun Mar 15, 2009 12:46PM EDT (AP)
Computer-virus infections don't cause your machine to crash anymore.
Nowadays, the criminals behind the infections usually want your computer operating in top form so you don't know something's wrong. That way, they can log your keystrokes and steal any passwords or credit-card numbers you enter at Web sites, or they can link your infected computer with others to send out spam.
Here are some signs your computer is infected, tapped to serve as part of "botnet" armies run by criminals:
• You experience new, prolonged slowdowns. This can be a sign that a malicious program is running in the background.
• You continually get pop-up ads that you can't make go away. This is a sure sign you have "adware," and possibly more, on your machine.
• You're being directed to sites you didn't intend to visit, or your search results are coming back funky. This is another sign that hackers have gotten to your machine.
So what do you do?
• Having anti-virus software here is hugely helpful. For one, it can identify known malicious programs and disable them. If the virus that has infected your machine isn't detected, many anti-virus vendors offer a service in which they can remotely take over your computer and delete the malware for a fee.
• Some anti-virus vendors also offer free, online virus-scanning services.
• You may have to reinstall your operating system if your computer is still experiencing problems. It's a good idea even if you believe you've cleaned up the mess because malware can still be hidden on your machine. You will need to back up your files before you do this.
How do I know what information has been taken?
• It's very hard to tell what's been taken. Not every infection steals your data. Some just serve unwanted ads. Others poison your search result or steer you to Web sites you don't want to see. Others log your every keystroke. The anti-virus vendors have extensive databases about what the known infections do and don't do. Comparing the results from your virus scans to those entries will give you a good idea about what criminals may have snatched up.
(AP)
Saturday, March 7, 2009
Energy vampires: Fact versus fiction
By Lori Bongiorno Which electronic devices waste the most energy when they are turned off but still plugged in? Set-top cable boxes and digital video recorders are some of the biggest energy hogs. Unfortunately, there's little consumers can do since television shows can't be taped if boxes are unplugged. It also typically takes a long time to reboot boxes. However, some of the other major consumers of standby power are more easily dealt with: computers, multifunction printers, flat-screen TVs, DVDs, VCRs, CD players, power tools, and hand-held vacuums. The Lawrence Berkeley National Laboratory (LBNL) measured standby power for a long list of products. While it's true each individual product draws relatively little standby power, the LBNL says that when added together, standby power can amount to 10% of residential energy use. Why do electronic devices use energy when they are switched off? Electronics consume standby power for one of two reasons, says Chris Kielich of the Department of Energy. They either have an adapter that will continue to draw electricity, or they have devices (such as clocks and touchpads) that draw power. Anything with a remote control will also draw standby power, she says, since the device needs to be able to detect the remote when it's pushed. Does everything suck energy when it's plugged in and turned off? No. If your coffeemaker or toaster doesn't have a clock, then it's probably not using standby power, says Kielich. Chances are your hair dryer and lamps (although they may have a power adapter for the dimmer) are not drawing standby power either, she says. Devices with a switch that physically breaks the circuit don't consume standby power. Will switching things on and off shorten their life? Probably not, says Kielich. You'd have to turn devices on and off thousands of times to shorten their lives. The real downside, she says, to unplugging electronics is that clocks and remotes will not work, and you do have to reset everything. Can you ruin batteries by unplugging battery chargers and causing batteries to completely discharge? It could be a possibility, says Kielich. Her advice: Don't let batteries get completely drained. But you don't need to have things like hand-held power vacuums and drills plugged into the charger when it's 100% charged, or even 50% charged. Power Strip FAQs Plugging electronics into a power strip and turning it off when you're not using it is a widely prescribed solution for curbing vampire power. Here are answers to common questions:
Posted Thu Feb 26, 2009 2:52pm PST
It's well-known that most electronic devices in our homes are sucking up energy even while they are turned off. But for all the information out there, many questions remain. I got hundreds of reader questions after writing the post What's wasting energy in your home right now. Below are answers to the five most common inquiries:
Sunday, March 1, 2009
Why Hair Goes Gray
Study Blames a Chain Reaction That Makes Hair Bleach Itself From the Inside Out
By Miranda Hitti
Feb. 25, 2009 -- Scientists may have figured out why hair turns gray, and their finding may open the door to new anti-graying strategies.
New research shows that hair turns gray as a result of a chemical chain reaction that causes hair to bleach itself from the inside out.
The process starts when there is a dip in levels of an enzyme called catalase. That catalase shortfall means that the hydrogen peroxide that naturally occurs in hair can't be broken down. So hydrogen peroxide builds up in the hair, and because other enzymes that would repair hydrogen peroxide's damage are also in short supply, the hair goes gray.
Putting the brakes on that chemical chain reaction "could have great implications in the hair graying scenario in humans," write the researchers, who included Karin Schallreuter, a professor clinical and experimental dermatology at England's University of Bradford.
The study appears online in The FASEB Journal; the FASEB is the Federation of American Societies for Experimental Biology.
WebMD Health News
SOURCES:
Wood, J. The FASEB Journal, Feb. 23, 2009; online edition.
News release, Federation of American Societies for Experimental Biology.
Tuesday, February 17, 2009
ငါအိုသွားသောအခါ
ငါအိုသွားသောအခါ ငါဟာ အရင်က ငါမဟုတ်တော့ဘူး။ ငါ့ကို နားလည်ပေးပါ၊ စိတ်ရှည်ရှည်ထား ဆက်ဆံပေးပါ။
ချည့်နဲ့နဲ့ လက်တွေနဲ့ ထမင်းဟင်းတွေ အင်္ကျီပေါ်ဖိတ်စင်သွားတဲ့အခါ အင်္ကျီ၊ လုံချည်၊ ဖိုသီဖတ်သီဖြစ်နေတဲ့အခါ ငါ့ကိုမရွံပါနဲ့၊ ငယ်ငယ်တုန်းက ငါသုတ်သင်ပေးခဲ့တာတွေကို ကျေးဇူးပြုပြီး သတိရပေးပါ။
အပ်ကြောင်းထပ်မက ပြောဖူးတဲ့စကားတွေ ပြန်ပြောမိတဲ့အခါ စကားမဖြတ်ဘဲ ကျေးဇူးပြုပြီးနားထောင်ပေးပါ။ ငယ်ငယ်တုန်းက အိပ်ရာဝင်တိုင်း တစ်ထောင့်တစ်ညပုံပြင်တွေ၊ ငါးရာငါးဆယ်နိပါတ်တော်တွေ၊ ဇာတ်ကြီးဆယ်ဘွဲ့တွေ စတဲ့ ပုံပြင်တွေကို မရိုးအောင်ပြောရင်း ငါချော့သိပ်ခဲ့တာတွေကို သတိရပေးပါ။
မလှုပ်ရှားနိုင်လို့ ရေချိုးဖို့ အကူအညီလိုတဲ့အခါ ငါ့ကို မငြိုငြင်ပါနဲ့။ ငယ်ငယ်တုန်းက ချော့တစ်လှည့်၊ ခြောက်တစ်လှည့် ရေချိုးပေးခဲ့ဖူးတဲ့ ပုံရိပ်လေးကို မြင်ယောင်ပေးပါ။
ခေတ်သစ် နည်းပညာသစ်တွေကို မသိနားမလည်ခဲ့ရင် မလှောင်ပါနဲ့။ ငယ်ငယ်တုန်းက "ဘာကြောင့်ဆိုတဲ့" မေးခွန်းတိုင်းကို စိတ်ရှည်စွာ ငါပြန်ဖြေခဲ့တာကို သတိရပေးပါ။
စိတ်သွားတိုင်းကိုယ်မပါ နွမ်လျပြီး လမ်းမလျှောက်နိုင်တဲ့အခါ ခွန်အားပါတဲ့ လက်တစ်စုံနဲ့ ငါ့ကိုကူတွဲပေးကြပါ။ လမ်းလျှောက်သင်စ အရွယ်တုန်းက တစ်လှမ်းချင်း လှမ်းလျှောက်လေ့ကျင့်ပေးခဲ့တာတွေကို သတိရပေးပါ။
တစ်နေ့ထက်တစ်နေ့ အိုစာသွားတဲ့ ငါ့ကို ကြည့်ပြီး ဝမ်းမနည်းပါနှင့် နားလည်ပေးပါ အားပေးပါ အရင်တုန်းက လူ့ဘဝတက်လမ်းအတွက် ငါလမ်းညွှန်ခဲ့သလို အခုချိန်မှာ ငါ့ဘဝနောက်ဆုံး အချိန်အတွက် အဖော်ပြုပေးပါ။ ချစ်ခြင်းမေတ္တာနဲ့ အေးမြမှုကို ငါပြုံးပြုံးလေး လက်ခံမှာပါ။ အဲ့ဒီ အပြုံးတွေထဲမှာ မဆုံးတဲ့ မေတ္တာတွေ တွေ့ရမှာပါ။
သားတို့သမီးတို့ရေ ------ ထာဝရပျော်ရွင်ချမ်းမြေ့ကြပါစေကွယ်------။
ရေးသူမသိပါ။ လက်ကမ်းစာစောင်တစ်စောင်မှ
Sunday, February 15, 2009
Are You Wasting Money on Multivitamins?
By Simeon Margolis, M.D., Ph.D. - Posted on Wed, Feb 11, 2009, 3:28 pm PST
Advertisements with tantalizing promises of improved health, prevention of cancer and heart disease, and greater energy have lured millions of Americans to spend billions of dollars on the purchase of multivitamins.
An article in the February 9 issue of Archives of Internal Medicine reported that multivitamin use did not protect the 161,808 postmenopausal women enrolled in the Women's Health Initiative Study from common forms of cancer, heart attacks, or strokes. And the numbers of deaths during the 8 years of the study were the same in vitamin users as in non-users. Still, it is important to recognize that this was an observational study, not a more meaningful clinical trial. Although these findings apply only to women, other studies have failed to show benefits of multivitamins in older men.
These results are not at all surprising for several reasons. No large study has shown that multivitamins significantly benefit healthy men and women. In addition, for some years physicians prescribed folic acid and vitamins B12 and B6 in the hopes of preventing heart attacks and strokes by lowering blood levels of homocysteine. (High blood levels of homocysteine are associated with an increased risk of coronary and other vascular diseases.) A number of recent studies, however, have shown that, while these vitamins do lower homocysteine levels, they do not prevent heart attacks or strokes.
Many doctors have also prescribed the antioxidants vitamin E and beta-carotene to reduce the risk of cardiovascular diseases and cancer. Alas, studies have now proven that these supplements are not protective--and may even be harmful.
No one denies that an adequate intake of vitamins is essential; however, vitamins can and should be obtained from eating enough healthy foods rather than from swallowing vitamin supplements.
Then what about vitamins being a great source of energy? Some multivitamin ads do indeed claim that their supplements boost energy; and some professional athletes gobble handfuls of vitamin pills to increase their energy and strength. But researchers proved long ago that energy comes from calories, not vitamins. The highly touted cholesterol-lowering effects of substances added to some multivitamin supplements? Still unproven.
All this is not to say that specific vitamins supplements are never desirable. Vitamins can be valuable in certain situations:
- Folic acid supplements in women who are pregnant or plan to become pregnant can help to prevent serious neural-tube defects that affect the baby's brain and spine.
- Supplements that contain more vitamin D and calcium than is present in regular multivitamin pills can help older men, and especially women, avoid osteoporosis and bone fractures.
- Supplements of vitamins C and E, beta-carotene, zinc, and copper may slow the progression of vision loss in people with early macular degeneration.
And multivitamins are beneficial for some entire groups of people:
- those on a very-low-calorie weight-loss diet
- strict vegetarians
- heavy alcohol drinkers
- individuals who are not getting an adequate diet because they are too sick or too poor--or live by themselves and are unable to prepare proper meals for themselves
I also agree with a comment made by one of the coauthors of the Archives of Internal Medicine article about postmenopausal women mentioned above. An 8-year follow-up period may not be long enough to show that multivitamins protect against cancers that take many years to develop.
All the same, the results of the studies on vitamins so far point to one conclusion: Healthy people who eat enough calories from a varied diet do not benefit from multivitamin supplements.
