Parasitology. Close encounters: good, bad, and ugly

Microbiologists often focus on one organism and its relationship to its host at one point in time. But viewed in light of evolution, host-parasite relationships range from deadly to helpful, depending on the communication between them. At a meeting here last month of virologists, bacteriologists, parasitologists, and molecular biologists--each dealing with different microorganisms in distinct ways--researchers lamented that evolution is often considered outside the bailiwick of microbiologists, particularly those studying infectious diseases.     

U.s. Farm dilemma: the global bad news is wrong

World agricultural production is at an all-time high and is climbing fast, especially in the developing countries. Even Africa has ample land and technology to feed its population, given more effective national policies. Higher agricultural output has been stimulated primarily by new technology, but also by investments and improved government policies. Constraints such as cropland shortage, soil erosion, and higher oil prices have been readily surmounted. High-technology agriculture has even overcome some major "systems breaks." Thus U.S. farmers will continue to face commercial surpluses of farm products in world markets in the years ahead.     

未成年人不良行为的表现 成因及矫正

未成年人不良行为的形成,是未成年人自身的主观因素与外界不良因素影响相互作用的结果。把家庭教育、学校教育与社会教育结合起来,积极构建家庭、学校和社会“三结合”的教育网络,是预防和矫正未成年人不良行为,遏止违法犯罪的有效途径。