tailieunhanh - Cancer causes and cancer research on many levels of complexity

Active follow-up usually means that the registry attempts to contact physi- cians or patients on a regular basis to see if the patient is still alive. Because this is expensive, many registries rely on passive follow-up, matching with death certificates and assuming patients are alive otherwise. Mixed systems use death certificates plus updating the ‘date last known alive’ from hospital admissions, consultations, and other sources of data. Active follow-up of the patients is usually very difficult in developing coun- tries. Few registries have the necessary facilities for regular follow-up of patients. There are also problems with unreliable postal services, unstable addresses and mobility of the population. Passive follow-up is. | Cancer causes and cancer research on many levels of complexity Sunny Y. Auyang America has poured about 200 billion dollars into cancer research since President Nixon declared war on cancer in 1971. How is the war going after three decades Why do assessments vary as widely as beating cancer and loosing the war on cancer Today the boundaries between medical and biological disciplines have vanished. . . . In an anatomy department biologists chemists and physicists can present the human body to medical students as an uninterrupted ascent from atoms to man from the tens of atoms that make a small molecule to the thousands of molecules that make a polymer such as a protein or a nucleic acid to the millions of such polymers that make a cell to the billions of cells that make a tissue and the trillions of specialized cells that create a body. In a wider panoramic view the human body and its behavior becomes a tiny decoration in the tapestry of life interwoven with the incredible variety of plasmids viruses bacteria plants and animals in a 4-billion-year evolutionary development. Thus observed physician and biochemist Arthur Medical students are not alone in confronting myriad levels of complexity and scales of spatial and temporal organization. Freshman biology textbooks present a similar panorama from chemical bonds between atoms to the evolution of ecological systems. A first lesson for physics students is the vast range of scales from subatomic particles to medium-size things we handle everyday to galaxies and the universe itself. The expansive education is invaluable. When students later specialize in a particular area of research they are likely to focus on one or a few levels that are more relevant than the others. The concentration comes with the risk of digging oneself into a hole and studying the sky from the bottom a well as is expressed by ideologies asserting that all is nothing but genes or nothing but ecology. To avoid such traps is a constant .