I magine a society with perfect economic equality. Perhaps out of sheer coincidence, the supply and demand for different types of labor happen to produce an equilibrium in which everyone earns exactly the same income. As a result, no one worries about the gap between the rich and poor, and no one debates to what extent public policy should make income redistribution a priority. Because people e...

That tired Ten-Percent claim pops up all the time. Last year, national magazine ads for U.S. Satellite Broadcasting showed a drawing of a brain. Under it was the caption, "You only use 11 percent of its potential." Well, they're a little closer than the ten-percent figure, but still off by about 89 percent. In July 1998, ABC television ran promotional spots for "The Secret Lives of Men," one of...

An information retrieval performance measure that is interpreted as the percent of perfect performance (PPP) can be used to study the effects of the inclusion of specific document features or feature classes or techniques in an information retrieval system. Using this, one can measure the relative quality of a new ranking algorithm, the result of incorporating specific types of metadata or folk...

Immunoglobulin A (IgA) and alveolar macrophages are two important components of the immune system in the respiratory tract. Fc alpha-receptors (Fc alpha R) are present on neutrophils, eosinophils and a series of human mononuclear phagocytes, including monocytes, alveolar macrophages and leukaemia cell lines (U-937). In the present study, using idiotypes and anti-idiotypic antibodies, we report ...

Recent studies have proposed that tumor necrosis factor alpha (TNF-alpha) and ionizing radiation induce apoptosis by activating hydrolysis of sphingomyelin to ceramide. Bcl-2 and a related gene, Bcl-X, inhibit several forms of apoptosis. Herein, we report that internucleosomal DNA fragmentation, characteristic of apoptosis and induced by ionizing radiation, is accompanied by concomitant decreas...

damage. UVB exposure of human skin induces skin alterations, including erythema, which is characteristic of sunburn cells, and prolonged UVB exposure results in the formation of wrinkles, the degradation of matrix molecules, the development of elastosis, and an increased risk of epithelial skin cancer. Keratinocytes are the main target of UV, and play a central role in several responses of phot...