Reena Khare

Food Taboos, Diet, and Hunting Strategy: The Adaptation to Animals in Amazon Cultural Ecology [and Comments and Reply]

The issue of food prohibitions on such Amazonian game animals as deer is examined from an ecological perspective, in contrast to previous symbolic or structuralist views on this subject. Examined in conjunction with settlement pattern, technology, animal behavior, and habitat productivity, which together determine the food-extraction potential of a population, the avoidance of certain inherently edible species by characterizing them as inebible is seen as selective use of the environment to resolve the relative costs and benefits of alternative procurement options through a strategy of optimum yield. It is shown how the interaction of technoeconomic variables and the differential biotic potential of various species produces a particular set of cultural assumptions about the edibility of such animals and that such selectivity represents a cost-effective strategy of protein acquisition and not a merely metaphysical product.

High-brightness AlGaInN light-emitting diodes

Currently, commercial LEDs based on AlGaInN emit light efficiently from the ultraviolet-blue to the green portion of the visible wavelength spectrum. Data are presented on AlGaInN LEDs grown by organometallic vapor phase epitaxy (OMVPE). Designs for high-power AlGaInN LEDs are presented along with their performance in terms of output power and efficiency. Finally, present and potential applications for high-power AlGaInN LEDs, including traffic signals and contour lighting, are discussed.

High-flux and high-efficiency nitride-based light-emitting devices

There are numerous materials challenges involved in the production of high-efficiency III-nitride lasers and LEDs, some of which can be mitigated by epitaxy and device physics. The lack of a suitable lattice-matched substrate for epitaxy of AlInGaN films results in high dislocation densities and a large amount of residual strain in the deposited films. The role of the dislocations is not well-understood, although there is clear evidence that laser reliability is improved by reducing their density.

High-power AlInGaN light-emitting diodes

High-power light-emitting diodes (LEDs) in both the AlInGaP (red to amber) and the AlGaInN (blue-green) material systems are now commercially available. These high-power LEDs enable applications wherein high flux is necessary, opening up new markets that previously required a large number of conventional LEDs. Data are presented on high-power AlGaInN LEDs utilizing flip-chip device structures. The high-power flip-chip LED is contained in a package that provides high current and temperature operation, high reliability, and optimized radiation patterns. These LEDs produce record powers of 350 mW (1A dc, 300 K) with low (<4V) forward voltages. The performance of these LEDs is demonstrated in terms of output power, efficiency, and electrical characteristics.