knowledge

  The pyramids built by the ancient Egyptians are among the most well known and celebrated in the world. Egyptians engineered the model for what most of us consider the classic pyramid design: a square base and four smooth triangular sides.  The awesome design and massive size of the pyramids have evoked some fanciful explanations. Some people have suggested that inhabitants of the legendary Atlantis extraterrestrials built them, while others claim levitation was used or that the Egyptians possessed a now-lost, unique technology to help them erect the remarkable structures. Indeed, there is no known Egyptian hieroglyph or relief or any surviving written account from that time depicting the building of the pyramids. For centuries, Egyptologists, scientists, engineers, writers, and mathematicians have theorized how the pyramids were built. All agree, however, about the basic techniques of pyramid construction.    Copper chisels were used to quarry softn rocks such as ...

       Di fferent religions throughout the world claim to understand what happens to us after we die. Scientists are not as certain. They can explain, of course, what happens in and to our bodies at the moment of death and just after.     To doctors, clinical death comes when the heart goes into cardiac arrest, which can occur from a variety of causes—from a car accident to illness. In effect, most of us die from cardiac arrest. The heart stops beating, cutting off the flow of blood, and thus oxygen, to the brain. Next comes biological death, as the brain, other organs, and cells stop functioning because of a lack of oxygen.    Before reaching that point, however, in  the window between clinical and biological death, doctors have been able to start the heart beating again, thus preventing death, or irreversible brain damage due to lack of oxygen. Thanks to research over the past several decades, doctors can now revive people whose hearts hav...

निर्धारित पैरामीटर 20 अरब डॉलर से अधिक है। साथ ही भारत का फॉरेन एक्सचेंज का नेट पर्चेज 64 अरब डॉलर रहा जो 2.4 फीसदी है। दो पैरामीटर लागू होने के चलते भारत को करंसी मैनिपुलेशन मॉनिटरिंग (Currency manipulation) की लिस्ट में रखा गया है  हाल ही में अमेरिका ने भारत, ताइवान, थाईलैंड, चीन, जर्मनी, इटली, सिंगापुर और मलेशिया जैसे देशों को करंसी मैनिपुलेटर की लिस्ट में डाल दिया है। करीब डेढ़ साल पहले भी भारत को इस लिस्ट में डाला गया था और अब फिर से भारत को इस लिस्ट में डाल दिया गया है। आइए समझते हैं कि आखिर भारत ने ऐसा क्या किया कि उसे इस लिस्ट में डाला गया। जानते हैं कि क्या होता है करंसी मैनिपुलेशन (Currency manipulation) और अमेरिका किन देशों को इस लिस्ट में डालता है। क्या है करंसी मैनिपुलेशन? जब भी अमेरिका को ऐसा लगता है कि कोई देश गलत तरीके से कोई करंसी प्रैक्टिस कर रहा है, जिससे अमेरिकी डॉलर की कीमत पर असर पड़ रहा है तो अमेरिकी सरकार का ट्रेजरी डिपार्टमेंट उस देश को करंसी मैनिपुलेटर का लेबल दे देता है। यानी इसमें देश जानबूझकर अपनी करंसी की वैल्यू को किसी तरह कम करता है, जिससे दूसरे देशो...

   Gesundheit! You step out into bright sunshine after spending a couple of hours in a dark movie theater and immediately experience a sneezing fit. Does this happen to you often? Does it happen to your children? The Sun induces sneezing in 10 percent of the U.S. population, says Louis J. Ptácek, a neurologist at the Howard Hughes Medical Institute in Maryland and a professor at the University of California at San Francisco. Just how and why this happens, though, has remained a mystery ever since Aristotle raised the question some 2,300 years ago.       Research suggests that the photi wec sneeze reflex, or PSR, is inherited, but scientists have yet to pinpoint the gene or genes responsible. “There’s precious little known about PSR, and part of that is because it’s not a disease,” Ptácek says. “No one dies from it.”     One theory is that the gene involved— whatever it is—crosses wires in the brains of those with PSR. For these people, light entering ...

          If you’ve ever chugged a carbonated drink, felt overwhelmed by fear, or experienced a bloated stomach, you might have hiccuped soon after.  These and other actions and conditions can trigger hiccups, and sometimes they start for no clear reason at all. Hiccups—singultus in the medical world— occurs during the breathing process when the diaphragm breaks out of its normal rhythm of moving up and down and suddenly contracts involuntarily. When this happens, air rushes down the throat and hits the vocal cords as they shut, creating the “hic” sound.       Although hiccups are a common occurrence, they don’t seem to have any real biological purpose. As to why they happen, one theory is that the nerves that control the vocal cords and the diaphragm get out of whack, for some reason scientists don’t understand. The malfunction could result from damage or irritation to those nerves. From an evolutionary standpoint, hiccups may have once bee...

      Ponce de León sought the fountain of youth. People today pin their hopes on diets, supplements, exercise, or plastic surgery. It’s a fact: Humans age, and lots of us don’t like how aging makes us look or feel. But what if we were able to slow the aging process?    Scientists call the process of aging senescence. Why we age, according to Marquette University professor Sandra Hunter, is rather simple: “Cell death… eventually leads to systems malfunctioning and whole body death.” For example, muscle fibers and nerves connected to them gradually die, leading to a loss of strength that begins at age 50 and continues steadily thereafter.   A deeper question for scientists is, why do the cells die? They’ve come up with several theories, and most likely a combination of them explains the aging process. One theory rests on oxidative damage. Normal cell processes release harmful molecules called oxygen free radicals. Substances in the body called antioxidants...