......................Somkit....................

วันพฤหัสบดีที่ 20 กันยายน พ.ศ. 2550

...ลักษณะของข้อมูลหรือสารสนเทศที่ส่งผ่านระบบคอมพิวเตอร์และการสื่อสาร ดังนี้
ข้อมูลหรือสารสนเทศที่ใช้กันอยู่ทั่วไปในระบบสื่อสาร เช่น ระบบโทรศัพท์ จะมีลักษณะของสัญญาณเป็นคลื่นแบบต่อเนื่องที่เราเรียกว่า "สัญญาณอนาลอก" แต่ในระบบคอมพิวเตอร์จะแตกต่างไป เพราะระบบคอมพิวเตอร์ใช้ระบบสัญญาณไฟฟ้าสูงต่ำสลับกัน เป็นสัญญาณที่ไม่ต่อเนื่อง เรียกว่า "สัญญาณดิจิตอล" ซึ่งข้อมูลเหล่านั้นจะส่งผ่านสายโทรศัพท์ เมื่อเราต้องการส่งข้อมูลจากคอมพิวเตอร์เครื่องหนึ่งไปยังเครื่องอื่น ๆ ผ่านระบบโทรศัพท์ ก็ต้องอาศัยอุปกรณ์ช่วยแปลงสัญญาณเสมอ ซึ่งมีชื่อเรียกว่า "โมเด็ม" (Modem)

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Healthy Diet Could Wipe Out High Blood Pressure Epidemic

In a new American Heart Association scientific statement, the nation’s experts in hypertension research concluded that of all environment factors that affect blood pressure, from anxiety to toxins, dietary factors “have a prominent, and likely predominant, role in blood pressure control.” *
Healthy dietary changes – notably, a diet that emphasizes fruits, vegetables, whole grains, low-fat and nonfat dairy products, and reduced intake of salt, fats, red meat, and sweets – “could have an enormous beneficial impact,” wrote lead author Lawrence Appel, M.D., of Johns Hopkins University School of Medicine and colleagues.
Never were enormous benefits more important. More than one quarter of U.S. adults have high blood pressure while another 31% have pre-hypertension, which is systolic blood pressure (the upper number in a blood pressure reading) of 120 to 139 or diastolic blood pressure (the lower number) of 80 to 89.
“The risk of cardiovascular disease increases progressively as blood pressure levels rise. High blood pressure remains an epidemic in the United States, but it can be prevented,” said Dr. Appel in a statement released by the American Heart Association. “By improving their diet, people can reduce their blood pressure and put a major dent in their risk of cardiovascular disease, including stroke, coronary heart disease, and heart failure.”
Dr. Appel and fellow researchers urged all Americans, even those with normal blood pressure, to adopt healthier diets because as people in the U.S. and other industrialized countries age, blood pressure rises. Warned Appel: “While an individual’s blood pressure may be normal now, 90% of Americans over 50 years of age have a lifetime risk of high blood pressure. Americans should take action before being diagnosed with high blood pressure.”
After reviewing all pertinent scientific literature, the expert committee outlined five key diet-related steps proven to effectively lower blood pressure:
...1. Use an overall dietary strategy, like the Dietary Approaches to Stop Hypertension (DASH), which emphasizes fruits, vegetables, whole grains, and low-fat and nonfat dairy products. Like the Pritikin Program, DASH also includes moderate servings of poultry and seafood, and minimizes fats, red meat, and sweets. The scientists also pointed out that in industrialized countries, where high blood pressure is common, “individuals who consume a vegetarian diet have markedly lower blood pressures than do nonvegetarians.”
Clinical trials have proven that the blood-pressure-lowering effects of the DASH diet were rapid, occuring within only two weeks. Similarly, the Pritikin Program has been documented to dramatically lower blood pressure in less than four weeks. Recently published research found that of 1,117 hypertensives studied, the majority returned home from the Pritikin Longevity Center with blood pressures in the normal range, and no longer requiring anti-hypertensive drugs. **
...2. Maintain normal weight or lose weight if overweight. One of the benefits of a healthier DASH-style diet is weight loss, pointed out the committee. The really good news: clinical trials have documented that even small reductions in weight – just 10 to 12 pounds – net significant reductions in blood pressure. To be sure, the more excess weight you lose, the more your blood pressure drops. And “a critical factor in sustaining weight loss is a high level of physical activity,” stated the committee.
...3. Lower salt (sodium chloride) intake as much as possible, ideally to about 1,500 mg a day. Rigorously controlled studies have determined that people consuming the lowest levels of sodium each day (1,500 mg versus 2,500 and 3300 mg) were rewarded with the most significant drops in blood pressure. ***Those who benefit the most from salt reduction, achieving the greatest drops in blood pressure, are blacks, middle-aged and older persons, and individuals with hypertension, diabetes, or chronic kidney disease, reported the committee.Because more than 75% of the salt Americans consume come from processed foods, the AHA expert team called on food manufacturers and restaurants to “progressively reduce the salt added to foods by 50% over the next 10 years.”
...4. Increase potassium intake by eating 8 to 10 servings of fruits and vegetables each day. High potassium intake is associated with reduced blood pressure, even in people without high blood pressure, and “in several trials, the effects of increased potassium intake in blacks have been particularly striking,” noted the authors.The recommended amount, identical to the recommendation of the Institute of Medicine, is 4.7 grams daily. Food sources such as fruits and vegetables are far preferable to supplements, pointed out the committee, “because potassium derived from foods is also accompanied by a variety of other nutrients.”
...5. Moderate the intake of alcohol. Studies have shown that, particularly for those drinking more than two drinks a day, the more you drink, the higher your blood pressure soars. A recently published analysis of 15 trials showed that consuming less alcohol reduces both systolic and diastolic blood pressure. **** The scientific committee’s recommendation: No more than two drinks a day for most men and no more than one drink daily for women and lighter-weight persons.

......................Somkit....................

วันพฤหัสบดีที่ 20 กันยายน พ.ศ. 2550

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