I plan to add some pure water here

medline

I remember who you are base on your post.

[em04]

medline

en.
it's a good idea.


Today's sciencetific news:
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MIT 'Seeing Machine' Offers Hope To Blind (May 23, 2006) — An MIT poet has developed a small, relatively inexpensive "seeing machine" that can allow people who are blind, or visually challenged like her, to access the Internet, view the face of a friend, "previsit" unfamiliar buildings and more. >
full storyfull story link

medline

Today's science news:

Selfish OR Selfless?

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link

http://www.sciencedaily.com/releases/2006/05/060524223113.htm

Survival Of The Selfless: Scientists Find Cheats Don't Always Prosper

Selfishness is not necessarily the best survival trait for microorganisms, according to researchers studying the comparative effectiveness of 'cheating' and 'cooperating' strains of yeast.


Writing in the journal Nature today, the team reports that studies of lab-grown yeast populations suggest the benefits of cheating are eventually counterbalanced by the costs. This contradicts classic evolutionary theory, which states that in a competition for common resources the long-term winner will always be the individual acting selfishly rather than the one working as part of a group.

To test this theory, scientists set up a series of competitions between two strains of yeast. The strains are identical apart from the genes that determine whether they convert energy from resources such as sugar rapidly or if they convert it efficiently.

In one corner were the 'cooperators', which produce energy efficiently by taking in sugar slowly and fully converting into energy all that they ingest. This method maximises resources available to the group by avoiding any waste.

Against them were the 'cheaters', which produce energy rapidly by quickly taking in all the sugar they can and only partially converting it into energy. While this ensures swift energy production for the individual, it is a wasteful method that reduces resources available for the group as a whole.

The researchers were surprised to find that in a well-mixed population the cooperators were not excluded by the cheats. Further experiments and mathematical modelling established that this is because cheats accumulate toxins as a direct result of taking in resources more quickly than they can digest them, which limits the level of energy they derive from the sugar. This enables the cooperators to hold their own, meaning that the two different strains could coexist over the long-term without either being excluded. Lead researcher Dr Craig MacLean of Imperial College London says:

"This evidence that a cooperative group can resist invasion by exploitative cheats is unexpected and gives us greater insight into how cooperation evolves. This is important because we live in a world in which cooperations exists at every level, from genes working together to build functioning individuals to individuals forming societies."

The researchers suggest that the ideal organism type would be one that can switch between selfish and efficient metabolism. Dr MacLean adds:

"While microbes are obviously not capable of rational thought, they can change their behaviour rapidly in response to simple environmental cues. The possibility that one type could become both a cheater and a cooperator depending on what's needed at the time is intriguing. We hope examining social conflict at the level of individual cells will shed more light on this."

Artemisia

以下是引用Owl在2006-5-24 9:49:07的发言：
Why, medline and life like to try

here, life=wife?  [em04]

medline

to upstair neighbor.
yes

medline

Today's post of Sci news.

Researchers Confirm HIV-1 Originated In Wild Chimpanzees

An international team of scientists, led by researchers at the University of Alabama at Birmingham (UAB), has discovered a crucial missing link in the search for the origin of HIV-1, the virus responsible for human AIDS. That missing link is the natural reservoir of the virus, which the team has found in wild-living chimpanzees in southern Cameroon.

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The findings provide important clues to how the disease migrated from non-human to human primates, and will be released Thursday (May 25) in ScienceExpress and will be published in an upcoming issue of Science magazine.

Although researchers have long suspected that HIV-1’s origins lie in some way with chimpanzee infection through a closely related virus SIVcpz (simian immunodeficiency virus from chimpanzees), only a few captive apes had been found to harbor SIVcpz.

In the study, UAB Professor of Medicine Beatrice H. Hahn, M.D., and her team conducted the first-ever molecular epidemiological survey of SIVcpz infection in wild-living chimpanzees in west-central Africa. By analyzing ape fecal samples collected by trackers from the forest floor in remote jungle regions of Cameroon, Hahn and her colleagues were able to detect SIVcpz-specific antibodies and nucleic acids (viral genetic information) in as many as 35 percent of chimpanzees in some ape communities.

The UAB investigators went on to molecularly clone and sequence the complete viral genomes from four individual chimpanzees. According to UAB post-doctoral researcher Brandon Keele, Ph.D., lead author of the report, “this allowed for unprecedented genetic comparisons to be done between HIV-1 and its closest simian virus counterpart.” He went on to say that “finding this cluster of naturally infected chimpanzees will allow us to explore the natural history and behavior of SIVcpz in its natural host and help us begin to unravel how and why SIVcpz made the jump to humans.”

Hahn, who for more than a decade has led an international effort to elucidate the origins of HIV-1, emphasized that the current study could not have succeeded without a close working partnership with Cameroonian government officials and with other collaborating scientists, including George M. Shaw, M.D., Ying Ying Li, Jun Takehisa, Mario Santiago, Frederic Bibollet-Ruche, and Yalu Chen from UAB; Fran Van Heuverswyn, Florian Liegeois, Eric Delaporte and Martine Peters from the University of Montpellier, France; Elizabeth Bailes, Louise Wain, John Brookfield and Paul Sharp from the University of Nottingham, England; and Severin Loul, Eitel Mpoudi Ngole and Yanga Bienvenue from the Project Prévention du Sida au Cameroun (PRESICA).

medline

My Comment:  exercise is needed.

Exercise Reverses Unhealthy Effects Of Inactivity

Many of the detrimental effects of physical inactivity can be reversed, and in some cases improved, by a similar period of moderate exercise, Duke University Medical Center researchers have found in a new analysis of data from the first randomized clinical trial to evaluate the effects of exercise in sedentary overweight men and women.

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http://www.sciencedaily.com/releases/2006/06/060603091830.htm
Just as important, the trial participants who exhibited the greatest decline in physical status during inactivity benefited the most from exercise training, according to the researchers.

These findings linking the ability of exercise training to reverse the negative effects of inactivity can be attributed to the exercise alone, because the participants did not alter their diets during the trial, the researchers said.

"Continuing to lead an inactive lifestyle leads to a gradual decline in many important markers for cardiovascular health," said Jennifer Robbins, an exercise physiologist at Duke, who presented the results of the study June 2, 2006, at the annual meeting of the American College of Sports Medicine in Denver.

"The good news is that a small amount of physical activity can make a big difference in reducing the risks for developing such conditions as heart disease, stroke or diabetes," she said. "Our findings demonstrate that while the cost of choosing a sedentary lifestyle can be high, switching to an active way of life can be beneficial at any time."

The current study stemmed from a recently completed trial known as STRRIDE (Studies of a Targeted Risk Reduction Intervention through Defined Exercise). The trial, funded by a $4.3 million grant from the National Heart, Lung and Blood Institute, investigated the effects of exercise on sedentary overweight adults at risk for developing heart disease, diabetes, or both.

The STRRIDE trial, in which the intervention ran for six months, randomly assigned 334 participants into three different exercise groups and one control group.

"At the end of the trial, we were surprised to see that many markers of cardiovascular health declined in participants in the control group, who did not exercise," Robbins said. "Our Duke group decided to see if these negative effects could be reversed after the participants spent the same amount of time in an exercise program."

Of the 61 STRRIDE participants randomly assigned to the control group 53 agreed to the take part in the new study, which ran an additional six months. The researchers measured 17 biological factors known to increase cardiovascular risk, including waist size, physical fitness, visceral fat levels, body mass index, cholesterol levels, insulin sensitivity and indicators of metabolic syndrome, a precursor of diabetes.

"In the new analysis, we found that waist size, time to exhaustion, visceral fat and metabolic syndrome scores deteriorated significantly during the six-month period of inactivity during the original STRRIDE trial," Robbins said. "However, after six months of exercise training in the study, 13 of the 17 variables had either reverted to original baseline levels or even improved."

According to Robbins, only a moderate amount of exercise is needed to counteract the detrimental effects of inactivity in these individuals. The STRRIDE trial measured three levels of physical activity: the equivalents of 12 miles of walking per week, 12 miles of jogging per week or 20 miles of jogging per week. Participants worked out on treadmills, elliptical trainers or cycle ergometers in a supervised setting.

"When looking at the group as a whole, we found it wasn't the participants with the highest intensity of exercise who accounted for the combined beneficial effects," Robbins said. "That should be reassuring for people to know they don't have to do a high-intensity workout to get these benefits of exercise."

A previous analysis by the Duke group of the same STRRIDE participants, reported in 2005, found another unhealthy effect of physical inactivity: inactive participants gained an average of 2 pounds in six months.

"At that rate, it can be assumed that this group of inactive people would gain 20 pounds in five years," Robbins said. "This means this population of sedentary people needed to exercise just to maintain their current weight. However, our earlier studies have shown that people who exercise can derive many of the cardiovascular risk benefits even in the absence of weight loss."

The STRRIDE trial was led by Duke cardiologist William Kraus, M.D. The Duke team is currently enrolling patients in STRRIDE II, in which the team will study the effects of weight training, aerobic training, and aerobic and weight training combined on cardiovascular health.

Joining Robbins in the current study were Cris Slentz, Brian Duscha, Johanna Johnson and Lori Aiken of Duke, and Joseph Houmard and Jennifer McCartney of East Carolina University.

香孜

以下是引用medline在2006-5-9 8:34:16的发言：

5, I don't know how to improve writing skills.

         I think , you can write English diary or blog~

   I did it when I was 17.

MR. M, welcome more water !~ to be cool,

maybe can have a pool to swim

[em11][em11]

香孜

以下是引用medline在2006-5-18 3:44:37的发言：
I am really sorry that I post the abstract without translfation.

 

[em13][em11] Since you have felt sorry,

why always keeping that?

You could get chance no nee to say sorry[em12]

To me ,medical english is difficult,

[em16]

wx_walnut

pure water[em05] but why not spring water? Better for health[em07]