41.The most thrilling explanation is, unfortunately, a little defective. Some economists argue that powerful structural changes in the world have upended the old economic models that were based upon the historical link between growth and inflation.

　　42.The Aswan Dam, for example, stopped the Nile flooding but deprived Egypt of the fertile silt that floods left-all in return for a giant reservoir of disease which is now so full of silt that it barely generates electricity.

　　43.New ways of organizing the workplace——all that re-engineering and downsizing——are only one contribution to the overall productivity of an economy, which is driven by many other factors such as joint investment in equipment and machinery, new technology, and investment in education and training.

　　44.His colleague, Michael Beer, says that far too many companies have applied re-engineering in a mechanistic fashion, chopping out costs without giving sufficient thought to long-term profitability.

　　45.Defenders of science have also voiced their concerns at meetings such as The Flight from Science and Reason, held in New York City in 1995, and Science in the Age of （Mis）information, which assembled last June near Buffalo.

　　46.A survey of news stories in 1996 reveals that the antiscience tag has been attached to many other groups as well, from authorities who advocated the elimination of the last remaining stocks of smallpox virus to Republicans who advocated decreased funding for basic research.

　　47.The'true enemies of science, argues Paul Ehrllch of Stanford University, a pioneer of environmental studies, are those who question the evidence supporting global warming, the depletion of the ozone layer and other consequences of industrial growth.

　　48.This development——and its strong implication for US politics and economy in years ahead——has enthroned the South as America's most densely populated region for the first time in the history of the nation's head counting.

　　49.Often they choose——and still are choosing——somewhat colder climates such as Oregon, Idaho and Alaska in order to escape smog crime and other plagues of urbanization in the Golden State.

　　50.As a result, California's growth rate dropped during the 1970's, to 18.5 percent——little more than two thirds the 1960's growth figure and considerably below that of other Western states.

　　51.Unlike most of the world's volcanoes, they are not always found at the boundaries of the great drifting plates that make up the earth's surface; on the contrary, many of them lie deep in the interior of a plate.