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for November, 2010.
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
I realize that we did space last week, but oddly enough, that folder is STILL overflowing (there is NO space) so here are a few more stories about ‘everything else’. One of the things I like about astronomy is how it connects with just about ‘everything else’, and our first story is a prime example. Want to know why there are no camels in North America? What happened to the well-developed Native American Clovis culture? The answer is a girl’s best friend!
DIAMONDS IN THE SNOW
A group of geologists has recently discovered something extremely interesting in the Greenland ice sheet. Nano-sized diamonds. The finding supports a controversial hypothesis: that fragments of a comet struck across North America and Europe approximately 13,000 years ago causing widespread extinctions of animals and cultures.
The scientists are excited about the find because the discrete layer of microscopic diamonds is the first such layer ever found in glacial ice anywhere on Earth, including the polar ice sheets and alpine glaciers. The diamonds are so tiny that they can only be observed with special microscopes and they number in the trillions.
These scientists also reported the discovery of nano-size diamonds in a layer of sediment exposed on Santa Rosa Island, off the coast of Santa Barbara, Calif. The layer containing the nano-diamonds on Santa Rosa Island, as well as those in the Greenland ice sheet were laid down at roughly the same time as the disappearance of the Clovis culture, the earliest well-established and well-accepted human culture in North America. The time frame also corresponds with the time of extinction of many North American large animals like mammoths, camels, horses, and the saber tooth cat.
There is also evidence of widespread wildfires at that time and 13,000 years ago is also associated with a sharply defined cold snap called the Younger Dryas recorded widely across the northern hemisphere. The cause of this cooling has long been debated as well as the cause of the animal extinctions and human cultural shift.
A high proportion of the nano-size diamonds in the Greenland ice sheet show a hexagonal structure. These structures are only known to occur on Earth in association with cosmic impact events.
Scanning transmission electron microscope image of nanodiamonds from the Greenland ice sheet. (Credit: James C. Weaver, UCSB)
When the students who visit the Planetarium as me if the Earth will be hit by a big rock, I say “Yes, it’s just a matter of time.” And this story certainly lends credence to that answer. It also says that it doesn’t have to be a big rock. Apparently a comet works just as well!
I seem to have a few stories about comets, so let’s continue to learn a bit about the vagabonds of the solar system. And new theories recently published tell us that comets are really vagabonds.
IT CAME FROM SOMEWHERE ELSE
A new theory by an international team of astronomers postulates that many of the most well known comets, including Halley, Hale-Bopp and, most recently, McNaught, may have been born in orbit around other stars.
They used computer simulations to show that the Sun may have captured small icy bodies from its sibling stars while it was in its birth star cluster, thereby creating a reservoir for observed comets.
While the Sun has no companion stars, it is believed to have formed in a cluster containing hundreds of closely packed stars embedded in a dense cloud of gas. During this time, each star formed a large number of small icy bodies (comets) in a disk from which planets formed. Most of these comets were gravitationally slung out of these prenatal planetary systems by the newly forming giant planets, becoming tiny, free-floating members of the cluster.
The Sun’s cluster came to a violent end, however, when its gas was blown out by the hottest young stars. These new models show that the Sun then gravitationally captured a large cloud of comets as the cluster dispersed.
The computer simulations show that the Sun was probably astoundingly efficient at capturing the leftovers and it’s quite possible that this cloud contains a potpourri that samples material from a large number of stellar siblings of the Sun.
Evidence for the team’s scenario comes from the roughly spherical cloud of comets called the Oort cloud that surrounds the Sun and extends halfway to the nearest star. It had been assumed this cloud formed from the Sun’s proto-planetary disk. However the computer models predict that the Sun could not have produced such a large cloud all by itself.
How the Oort cloud formed has been a mystery for over 60 years and realizing that the Sun probably took some of the material from its own formation likely helps to solve the long-standing problem.
Comet Hale-Bopp photographed on April 9, 1997. (Credit: iStockphoto/Scott Orr)
Comets are indeed leftovers from the formation of the solar system, no matter where they came from originally. So what is a comet? Well, I tell the kids that a typical comet is a great big dirty iceberg. As it gets close to the Sun, the Sun’s heat melts the ice, gas escapes and some of the dirt falls out. This give the comet its long tail as it approaches the Sun. So why are scientists from Boston University’s Center for Space Physics reporting that Mercury looks like a comet?
A PLANET THAT LOOKS LIKE A COMET
They used a pair of NASA satellites designed to view the escaping atmosphere of the Sun to also record evidence of escaping gas from the planet Mercury. The STEREO mission has two satellites placed in the same orbit around the Sun that the Earth has, but the Lagrange points known as L4 and L5. These points are in the same orbit as Earth, but L4 is 60 degrees in front of Earth in its orbit and L5 is 60 degrees behind us.
Satellites at these Lagrange points offer multi-directional views of the electrons and ions that make up the escaping solar wind. Sometimes the planet Mercury appears in the field of view of one or both satellites. Not only have they spotted Mercury’s bright disk of reflected sunlight, a "tail" of emission can be seen in some of the images.
This isn’t the first time Mercury’s comet-like features have been observed. There’s a coma of tenuous gas surrounding the planet and a very long tail that extends away from the Sun. From Earth, observations of both of these features can be done using the light produced when sodium gas is sputtered off Mercury’s surface by the Sun’s intensive radiation. The Sun’s radiation pressure then pushes many of the sodium atoms in the anti-solar direction creating a tail that extends many hundreds of times the physical size of Mercury.
But the STEREO observations are too bright to be just produced by sodium and the focus of the current team of researchers is to sort out all of the possibilities for the gases that make up the tail. The researchers are working closely with members of the STEREO team responsible for the camera systems on both satellites to refine the brightness calibration methods, and determine the precise wavelengths of light that would get through the cameras’ filters.
The combination of ground-based data with the new STEREO data is enabling the scientists to learn as much as possible about the sources and fates of gases that escape from Mercury.
An image of Mercury’s tail obtained from combining a full day of data from a camera aboard the STEREO-A spacecraft. The reflected sunlight off the planet’s surface results in a type of over-exposure that causes Mercury to appear much larger than its actual size. The tail-like structure extending anti-sunward from the planet is visible over several days and spans an angular size exceeding that of a full Moon in the night sky. (Credit: Image courtesy of Boston University’s Center for Space Physics)
Comets. Sources of ice, dust and diamonds. And a planet that mimics a comet. Astronomy is a rich feast.
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
This week I thought we’d visit my favorite folder, the Space folder. As I tell my students and visitors to the Planetarium, I love my field because it changes every single day. Things that we thought were true last week may be looked at quite differently next week.
We’ll start our exploration with the most important thing in our lives; the Sun. And why is it the most important? Because if it wasn’t for the Sun, we wouldn’t be here. We’re lucky because our star is a remarkably steady star. If its output changed significantly, well, we wouldn’t be here. And with our increasing dependence on electrical power and electronics, the Sun has assumed an ever greater importance. Read on!
LIVING WITH A STAR
We now have several satellites tasked with the job of observing our star 24/7. It turns out that the Sun has weather just like Earth does and that weather occurs in 11 year cycles. We’re approaching the peak of the current cycle and solar astronomers are predicting a series of major solar storms in 2012 and 2013.
Solar storms involve the release of huge amounts of hot gas and magnetic forces from the Sun’s surface. They then travel into space at around a million miles an hour. A 2008 US National Academy of Sciences report estimated that our reliance on electronics and satellite communications means a major solar storm could cause twenty times more economic damage than Hurricane Katrina. Now, English researchers have developed a new method of predicting solar storms that could help to avoid widespread power and communications blackouts.
Our Sun not only puts out heat and light, it also puts out an incredible amount of matter. These major solar eruptions of matter are called coronal mass ejections CME’s), and they normally take several days to reach the Earth. But if they erupt with great violence and speed they can traverse the 93 million miles that separates us from our star in a matter of hours. The largest coronal mass ejection ever recorded in modern times was in 1859 and it got here in just 18 hours.
The energy produced in a massive CME is called a solar flare and that energy which can also disrupt communications systems gets here in eight minutes. Advance warning of solar storms can help avoid the worst effects of solar activity.
Solar weather prediction has been done manually, with experts looking at 2D satellite images of the sun and assessing the likelihood of future activity. But the British researchers from the University of Bradford have created the first online automated prediction system, using 3D images generated from the joint NASA/ESA Solar and Heliospheric Observatory satellite (SOHO).
The Bradford Automated Solar Activity Prediction system (ASAP) identifies and classifies sun spots and then feeds this information to a computer model which can predict the likelihood of solar flares. The system can accurately predict a solar flare six hours in advance and the team is working to achieve a similar accuracy for the prediction of major solar eruptions in the near future.
Since we rely on satellite communication for virtually everything here in the Marianas, a major disruption would cause havoc here. Being able to shut those satellites down before the Sun destroys them will be a big plus for us!
As I said earlier, we rely on our middle-sized, middle-aged star for everything and we are incredibly lucky that it’s so reliable and steady. Our star is typical of many of the stars in our galaxy. About half the stars out there are bigger than the Sun and about half are smaller. Virtually all the stars you see in the sky at night are bigger than the Sun because the bigger brighter ones are easier to see.
And there are bigger ones out there; much bigger . . . . . .
STELLAR FAT BOY
Astronomers have used the European Southern Observatory’s Very Large Telescope (VLT) in the Andes Mountains in Chili to discover the most massive star ever found. Its birth weight was more than 300 times the mass of the Sun, and twice as much as the currently accepted star-formation limit of 150 solar masses. The existence of this monster which is millions of times more luminous than the Sun may provide an answer to the question "how massive can stars be?
The astronomers used VLT data as well as archived data from the Hubble Space Telescope to study the young star cluster R136. R136 is a cluster of young, massive and hot stars located inside the Tarantula Nebula. The Tarantula Nebula is in one of the Milky Way’s satellite galaxies, the Large Magellanic Cloud and it’s 165 000 light-years away.
The team found several stars with surface temperatures over 40 000 degrees, more than seven times hotter than our Sun, and a few stars that were much larger and several million times brighter. The star R136a1, found in the R136 cluster, is the most massive star ever found. Its current weight is about 265 solar masses and since these new stars constantly lose weight with their massive solar winds (and you thought the Sun was bad!) it must have had a mass of as much as 320 times that of the Sun when nuclear fusion first began. Not only is R136a1 the most massive star ever found, but it also has the highest luminosity too. It’s close to 10 million times brighter than the Sun.
Very massive stars produce very powerful outflows. Unlike humans, most stars are born heavy and lose weight as they age. R136a1 is over a million years old which is middle-aged for a star of this size. It has already lost a fifth of its initial mass over that time, or more than fifty solar masses."
If R136a1 replaced the Sun in our Solar System, it would outshine the Sun by as much as the Sun currently outshines the full Moon. Its astounding mass would cause use to whiz around it in just three weeks instead of a year and since most of its energy output is in the high ultraviolet range, it would destroy all life on the Earth. (See, I told you we should be grateful for the Sun!)
These super heavyweight stars are extremely rare and form only in the densest star clusters. Within R136, only four stars weighed more than 150 solar masses at birth, yet they account for nearly half of the wind and radiation power of the entire cluster, which contains about 100 000 stars.
Stars between about 8 and 150 solar masses explode at the end of their short lives as supernovae, leaving behind exotic remnants, like neutron stars and black holes. Since we’ve now discovered the existence of stars that weigh between 150 and 300 solar masses, these latest findings raise the prospect that when these stars die they completely blow themselves apart and leave no traces behind. But they could release up to ten solar masses of iron when they explode. A few candidates for such explosions have already been proposed in recent years.
This artist’s impression shows the relative sizes of young stars, from the smallest “red dwarfs”, weighing in at about 0.1 solar masses, through low mass “yellow dwarfs” such as the Sun, to massive “blue dwarf” stars weighing eight times more than the Sun, as well as the 300 solar mass star named R136a1. (Credit: ESO/M. Kornmesser)
The fate of any star when it dies (and stars are just like people, they’re born, they grow up, they grow old and they die) is solely dependant on how much the star weighed to begin with.
Small, cool red stars burn their fuel for trillions of years and when it’s all gone they just quietly fade away. But larger stars have quite different fates. A star the size of our Sun becomes what’s called a white dwarf. It will swell first, and become what’s called a red giant, losing a lot of mass in the process and then eventually become an ultra dense and initially very hot object called a white dwarf. In its old age, the Sun will wind up being about the size of the Earth.
Larger stars become ultra-dense and rapidly spinning objects called neutron stars and even larger ones form the space and time distorting objects called ‘black holes’. As we’ve seen, the really large ones may just blow themselves to pieces.
But when stars like our Sun (and as I said earlier, most stars ARE like our Sun) die, they first produce what are called ‘planetary nebula’ although they have nothing to do with planets. These amazing structures are some of the most beautiful objects in the universe.
The Hubble Space Telescope, that marvel of science that has taught us more about ‘everything else’ that any other instrument ever built, underwent an overhaul last year and one of its cameras, the workhorse of the instrument, was replaced.
The Wide Field Planetary Camera 2 (WFPC2) was used to take this picture of a planetary nebula as its final "pretty picture." The nebula is called Kohoutek 4-55 (or K 4-55). This nebular has a bright inner ring is surrounded by a bipolar structure and it’s 4,600 light-years away in the constellation Cygnus.
During WFPC2’s amazing 16-year run, it provided spectacular images of the cosmos. Some of its best-remembered images are of the Eagle Nebula pillars, Comet P/Shoemaker-Levy 9’s impacts on Jupiter’s atmosphere, and the 1995 Hubble Deep Field — the longest and deepest Hubble optical image of its time.
Farewell WFPC2 and thank you for some pretty amazing ‘pretty pictures’!
WFPC2’s final "pretty picture." (Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) Acknowledgment: R. Sahai and J. Trauger (Jet Propulsion Laboratory))
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Greetings all! Well, the animal file is bulging and specifically we have lots of stories about the real multicellular lords of the planet. And of course, that isn’t us. For numbers and biomass, that award goes to the insects. Our first story is actually from the medical file and it concerns some good news about the most deadly killer on the planet.
CURING THE CARRIER
There is no question that mosquitoes are the most deadly killers on the planet because they carry malaria. Of the estimated 250 million people who contract malaria each year, 1 million, most of them children, do not survive. Ninety percent of the fatalities occur in Sub-Saharan Africa.
Each new malaria case starts when the person is bitten by a mosquito belonging to the genus Anopheles. About 25 species of Anopheles are significant vectors of the disease and we have Anopheles mosquitoes here in the Marianas.
Only the female Anopheles mosquitoes feed on blood, which they need to produce eggs. When they bite an infected human or animal, they ingest the malaria parasite which is a single-celled organism called Plasmodium.
Once the Plasmodium cells find themselves inside the mosquito, they spring into action. First, they leave the digestive tract by squeezing through the midgut wall. Most Plasmodium cells don’t survive this journey and are eliminated by the mosquito’s immune cells. A small number survive and attach themselves on the outside of the midgut wall where they develop into brooding cells called oocysts.
Within 10-12 days, thousands of new Plasmodium cells, called sporozoites, sprout inside the oocyst. After hatching from the oocyst, the sporozoites make their way into the insect’s salivary glands where they lie in wait until the mosquito finds a victim for a blood meal. When the mosquito bites, some sporozoites are flushed into the victim’s bloodstream. The average infected mosquito transmits about 40 sporozoites when it bites, but it takes only one to infect a human and make a new malaria victim.
Killing the mosquitoes is one way to halt the transmission of malaria, but unfortunately, they are becoming resistant to virtually every insecticide in the arsenal, and malaria is becoming a world-wide deadly plague. But what if you could prevent the mosquito from becoming infected?
For the first time, University of Arizona entomologists have succeeded in genetically altering mosquitoes in a way that renders them completely immune to the Plasmodium parasite. This raises the hope that it just might be possible to replace wild mosquitoes with lab-bred populations unable to transmit the malaria-causing parasite.
"If you want to effectively stop the spreading of the malaria parasite, you need mosquitoes that are no less than 100 percent resistant to it. If a single parasite slips through and infects a human, the whole approach will be doomed to fail," said Michael Riehle, a professor of entomology in the UA’s College of Agriculture and Life Sciences.
Riehle’s team used molecular biology techniques to design a piece of genetic information capable of inserting itself into a mosquito’s genome. This construct was then injected into the eggs of the mosquitoes. The emerging generation carries the altered genetic information and passes it on to future generations. For their experiments, the scientists used Anopheles stephensi, a mosquito species that is an important malaria vector throughout the Indian subcontinent.
The researchers engineered a piece of genetic code that acts as a molecular switch in the complex control of metabolic functions inside the cell. When Riehle and his co-workers studied the genetically modified mosquitoes after feeding them malaria-infested blood, they noticed that the Plasmodium parasites didn’t infect a single study animal.
"We were surprised how well this works," said Riehle. "We were just hoping to see some effect on the mosquitoes’ growth rate, lifespan or their susceptibility to the parasite, but it was great to see that our construct blocked the infection process completely."
But there are several reasons why it isn’t time to stand up and cheer yet. First, you can create these genetically modified wonders, but how do you get them to be so genetically superior they can replace the existing populations in the wild?
Riehle and his colleagues are also working to modify the mosquito’s genome to cut down on its lifespan. "In the wild, a mosquito lives for an average of two weeks," Riehle explained. "Only the oldest mosquitoes can transmit the parasite. If we can reduce their lifespan, we can reduce the number of infections."
At this point, the modified mosquitoes exist in a highly secured lab environment with no chance of escape. Once researchers find a way to replace wild mosquito populations with lab-bred ones, breakthroughs like the one achieved by Riehle’s group could pave the way toward a world in which malaria is all but history.
Me, I personally prefer a world in which the MOSQUITO is history, but they don’t seem to be working toward that as a goal. Unfortunately.
Of course, it can be argued that the mosquito’s job is biting me and eating my blood, and our next story is about a group of insects who have very strict job standards!
NO OVERTIME FOR THEM!
British researchers working at a station in northern Finland discovered something interesting. They tagged bumblebees with radio transmitters and used them to monitor the bees’ movements during the constant light of the Arctic summer. They found that the bees observe a strict working day, even when the Sun never sets.
This surprised the scientists because they assumed that constant daylight would provide a unique opportunity for the bees to maximize pollen intake and increase colony growth. They theorize that since the bees don’t take advantage of the opportunity, there’s some benefit to an ‘overnight’ break."
The researchers studied both native bees and a group of bee colonies they brought with them. Both species worked a day shift, with maximum activity around midday, and retired to their nests well before midnight. The researchers speculate the bees must have some way of telling the time in the absence of day/night cues. This suggests that the insects may be sensitive to light intensity and quality or changes in temperature.
Speaking about the possible advantages gained by taking some time off, the researchers said, "Despite the light, temperatures do fall during the Arctic ‘night’, so it may be that the bees need to return to their nests in order to warm their brood. Also, it has been suggested that a period of sleep helps bees to remember information gained during the day’s foraging."
These bumblebees are tagged with radio transmitters. (Credit: Stelzer et al., BMC Biology)
Although the Sun never sets in the far north in summer, it does move across the sky. Perhaps this movement is the clue for the bumblebees. We all know that insects have those remarkable compound eyes that give them an unimaginable view of the world. Well, at least most of them do. And now a story about an astounding insect that does NOT have compound eyes, but something else entirely.
SEEING THROUGH VERY DIFFERENT EYES
Researchers at the University of Cincinnati were doing research on the sunburst diving beetle (Thermonectus marmoratus) when they discovered something so totally unexpected as to be almost unbelievable. They found that the larva of the beetle has eyes that are essentially bifocals. It is the first report of truly bifocal lenses in the entire animal kingdom. The larva actually has 12 eyes and at least two of them are equipped with bifocals.
The sunburst diving beetle is a small beetle about the size of a lady bug (also a beetle) that lives in creeks and streams in the western United States. Like moths, butterflies and mosquitoes, it undergoes complete metamorphosis and the larvae, which also live in the water, look quite different from the adults. It’s the larvae that have the bifocal lenses. They lose them when they grow up.
As the researchers zeroed in on how the multiple eyes of this insect worked, they did even more research to try to disprove what they saw. They first used a microscope to look through the lenses of the two eyes. They saw how the lens could make a second image grow sharper — something that could only happen with a bifocal. The graduate student who first discovered the bifocals said "It was my first research project, and I seriously thought I made a mistake, and then we did additional research to try to kill the hypothesis." However, their findings were confirmed with more research in addition to observing the operation of the lens and the two focal planes via a microscope. They saw the bifocal again when they used a method to project a narrow light beam through the lens. "Our findings can only be explained by a truly bifocal lens," write the researchers.
The researchers explain that by using two retinas and two distinct focal planes that are substantially separated, the larvae can more efficiently use these bifocals, compared with the glasses that humans wear, to switch their vision from up-close to distance — the better to see and catch their prey, with their favorite food being mosquito larvae.
University of Cincinnati researchers are reporting on the discovery of a bug with bifocals — such an amazing finding that it initially had the researchers questioning whether they could believe their own eyes. (Credit: Elke Buschbeck)
And so we come full circle. Even though this is face only a mother could love, isn’t it just wonderful that their major food is mosquito larvae?
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Although I know we did medicine last week, the medical file still has an obesity problem, but here’s the good news. We’re only going to do good news stories and I promise next week to delve into space or global warming or archeology or animals or anything else besides what ails us! So off we go on our first adventure.
TWIRL THAT MOUSTACHE!
In a recent study using rats, scientists made an astounding discovery. The most common type of stroke can be completely prevented in rats by stimulating a single whisker, according to a study by California researchers.
Strokes are the No. 3 cause of death in the U.S., after heart disease and cancer. About 795,000 Americans suffer them annually, according to the American Heart Association, and more than 137,000 die as a result.
So should we be tickling our own whiskers? And what about women, who are less likely to have facial hair? While it’s too soon to tell if the findings will translate to humans, researchers say it’s possible, and that whiskers are not required. Humans have sensitive body parts wired to the same area of the brain as the fine-tuned whiskers of rats. The fingers, lips and the face in general could all have a similar effect.
A stroke usually happens when a main artery bringing oxygen and nutrients to the brain either ruptures or is blocked by a clot, causing partial brain death. The key to preventing strokes in rats whose main cerebral artery has been obstructed, UCI researchers found, is to stimulate the blood-starved brain area.
The team discovered that mechanically stroking just one whisker for four minutes within the first two hours of the blockage caused the blood to quickly flow to other arteries — like cars exiting a gridlocked freeway to find detours. But unlike freeway off-ramps, which can quickly clog, the alternate arteries expanded beyond their normal size, opening wide to allow critical blood flow to the brain. The technique was 100 percent effective in preventing strokes in rats with arterial obstruction.
Scientists have struggled for years to find ways of preventing strokes or minimizing their effects, which include slurred speech, paralysis and brain damage. People believed to be suffering a stroke are currently told to lie still and stay calm in a quiet environment. The Irvine researchers say that a good massage, listening to a song or otherwise stimulating the right nerve endings might work better.
They caution that the rodent findings might not be relevant to humans. But with such clear evidence that strokes in rats were prevented, they want to try controlled human studies. That’s tricky though, since you can’t predict when someone will have a stroke.
The UCI team would like to find physicians or emergency medical technicians willing to try the technique on patients with early stroke symptoms.
Signs of stroke include:
- Sudden numbness or weakness in face or limbs, especially on one side.
- Sudden confusion, trouble speaking or understanding.
- Sudden difficulty seeing or walking.
- Dizziness or loss of balance or coordination.
- Sudden, severe headache with no known cause.
If you or someone you know experiences one or more of these symptoms, call 911. The first two hours are critical. And while you’re waiting for the ambulance, try massaging the victim’s fingers or gently rubbing their face. You certainly won’t hurt them, and you just might make a big difference in their recovery!
Now that’s my kind of treatment! If it works, you will have done a great thing and if it doesn’t work you have done no harm. So, let’s move on to our next feel-good article. I’ll bet that the majority of the people who read this could stand to lose a few pounds. I know I could. So, are you ready for the next weight loss miracle? Trust me; you won’t see this one touted on TV!
WEIGHT LOSS MIRACLE!!!
Here it is! An appetite-control agent that requires no prescription, has no common side effects, and costs almost nothing!!! Scientists report results of a new clinical trial confirming that just two 8-ounce glasses of the stuff, taken before meals, enables people to shed pounds. The weight-loss elixir is (wait for it!) dihydrogen monoxide! That’s right ladies and gentlemen, it’s . . . . . water.
Brenda Davy, the senior author of the study reported that the team had discovered in earlier studies that middle aged and older people who drank two cups of water right before eating a meal ate between 75 and 90 fewer calories during that meal. In the recent study, they found that over the course of 12 weeks, dieters who drank water before meals, three times per day, lost about 5 pounds more than dieters who did not increase their water intake.
Davy pointed out that folklore and everyday experience long have suggested that water can help promote weight loss. But there’ve been surprisingly few scientific studies on the topic. (Probably because water isn’t produced by drug companies!) Previous studies hinted that drinking water before meals reduces caloric intake. But this is the first "gold-standard" evidence from a randomized, controlled clinical trial that compares weight loss among dieters who drink water before meals with those who do not.
The study included 48 adults aged 55-75 years, divided into two groups. One group drank 2 cups of water prior to their meals and the other did not. All of the subjects ate a low-calorie diet during the study. Over the course of 12 weeks, water drinkers lost about 15.5 pounds, while the non-water drinkers lost about 11 pounds.
Davy said water may be effective simply because it fills up the stomach with a substance that has zero calories. People feel fuller as a result, and eat less calorie-containing food during the meal. Increased water consumption may also help people lose weight if they drink it in place of sweetened calorie-containing beverages.
Diet soda and other beverages with artificial sweeteners may also help people reduce their calorie intake and lose weight. But the team advised against using beverages sweetened with sugar and high-fructose corn syrup because they’re so high in calories. A 12-ounce can of regular soda pop, for instance, contains about 10 teaspoons of sugar. Dr. Davy says “People should drink more water and less sugary, high-calorie drinks. It’s a simple way to facilitate weight management”
Drinking more water before meals can help promote weight loss, new research suggests. (Credit: iStockphoto/Lise Gagne)
And now, are you ready for the ultimate feel-good medical story???
THE HEART-SHAPED BOX
Middle-aged and elderly Swedish women who regularly ate a small amount of chocolate had lower heart failure risk. The nine-year study, conducted among 31,823 middle-aged and elderly Swedish women, looked at the relationship of the amount of high-quality chocolate the women ate, compared to their risk for heart failure. The chocolate consumed by the women was the equivalent of a high quality dark chocolate with a high cocoa content somewhat like dark chocolate by American standards.
In this study, researchers found:
- Women who ate an average of one to two servings of the high-quality chocolate per week had a 32 percent lower risk of developing heart failure.
- Those who had one to three servings per month had a 26 percent lower risk.
- Those who consumed at least one serving daily or more didn’t appear to benefit from a protective effect against heart failure.
The lack of a protective effect among women eating chocolate every day is probably because of the additional calories gained from eating chocolate instead of lower calorie foods.
Chocolate is, of course, pretty calorie-dense food and if you eat too much you raise your risk for weight gain. But the researchers say that if you’re going to have a treat, dark chocolate is probably a good choice, as long as it’s in moderation.
The benefits seem to correlate with a high content of cocoa in the chocolate and that’s bad news for Americans. Although 90 percent of all chocolate eaten across Sweden during the study period was milk chocolate, it contained about 30 percent cocoa solids. U.S. standards only require 15 percent cocoa solids to qualify as dark chocolate. So, by comparison, American chocolate may have fewer heart benefits and more calories and fat per equivalent amounts of cocoa content compared to the chocolate eaten by the Swedish women in the study.
And, of course, in the words of Linda Van Horn, immediate past chair of the American Heart Association Nutrition. "This is not an ‘eat all you want’ take-home message, rather it’s that eating a little dark chocolate can be healthful, as long as other adverse behaviors do not occur, such as weight gain or excessive intake of non-nutrient dense ‘empty’ calories."
A new study has found that middle-aged and elderly Swedish women who regularly ate a small amount of chocolate had lower risks of heart failure risks. (Credit: iStockphoto)
So, of course, we’re not going to go home and empty out the chocolate box, are we? But I think you’ll agree that any article that says that chocolate is good for you was worth the time to read.
Jim is, above all, a passionate eco-humanitarian who has developed his own science talk-radio show to inform The DEEP’s listeners about such newsy topics as global warming, shark-finning and reef protection as well as to explore earth’s many underwater and space mysteries.
sailing 12,000 miles and visiting five countries Jim is back here, ready to explore the depths of the ocean to the deepest frontier, space MORE>>
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