representing deformations in an infinite medium, a term related to surface deformation and that is multiplied by the depth of observation point. Several practical suggestions to avoid mathematical singularities and computational instabilities are also presented. The expressions derived here represent power-ful

For both biological systems and machines, vision begins with a large and unwieldy array of measurements of the amount of light reflected from surfaces in the environment. The goal of vision is to recover physical properties of objects in the scene, such as the location of object boundaries

The construction of a 0.58 lat 3 0.58 long surface climatology of global land areas, excluding Antarctica, is described. The climatology represents the period 1961–90 and comprises a suite of nine variables: precipitation, wet-day frequency, mean temperature, diurnal temperature range, vapor

Human alteration of Earth is substantial and growing. Between one-third and one-half interact with the atmosphere, with aquatic of the land surface has been transformed by human action; the carbon dioxide con- systems, and with surrounding land. Morecentration in the atmosphere has increased

number of membrane-bound, ultrastructurally well-preserved fragments. In the second stage these apoptotic bodies are shed from epithelial-lined surfaces or are taken up by other cells, where they undergo a series of changes resembling in vitro autolysis within phagosomes, and are rapidly degraded

with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulininduced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can

), leading to the assembly of a meshwork of actin filaments at the cell periphery to produce lamellipodia and membrane ruffles (Fig. 1E) (2). More re-cently, activation of Cdc42, a third member of the Rho subfamily, was shown to induce actin-rich surface protrusions called filopo-dia (Fig. 1G) (3, 4

, we introduce a framework for selectively refining an arbitrary progressive mesh according to changing view parameters. We define efficient refinement criteria based on the view frustum, surface orientation, and screen-space geometric error, and develop a real-time algorithm for incrementally refining

environment is static with only the viewing-position changing, as is common in simulation, the results presented will be safficient to solve completely tlae llidden surface proulem.;_N~a~OUCZZON One of the long-term goals of computer graphics has been, and continues to be, the rapid, possibly real

The historical surface temperature dataset HadCRUT provides a record of surface temperature trends and variability since 1850. A new version of this dataset, HadCRUT3, has been produced; benefiting from recent improvements to the sea-surface temperature dataset which forms its marine component