Modeling Structure and Dynamics of Selective Attention

We present a cognitive architecture that includes perception, memory, attention, decision making, and action. The model is formulated in terms of an abstract dynamics for the activations of features, their binding into object entities, semantic categorization as well as related memories and appropriate reactions. The dynamical variables interact in a connectionist network which is shown to be adaptable to a variety of experimental paradigms. We find that selective attention can be modeled by means of inhibitory processes and by a threshold dynamics. The model is applied to the problem of disambiguating a number of theories for negative priming, an effect that is studied in connection to selective attention

Extinction rate, historical population structure and ecological role of the Caribbean monk seal

The productivity and biomass of pristine coral reef ecosystems is poorly understood, particularly in the Caribbean where communities have been impacted by overfishing and multiple other stressors over centuries. Using historical data on the spatial distribution and abundance of the extinct Caribbean monk seal (Monachus tropicalis), this study reconstructs the population size, structure and ecological role of this once common predator within coral reef communities, and provides evidence that historical reefs supported biomasses of fishes and invertebrates up to six times greater than those found on typical modern Caribbean reefs. An estimated 233 000–338 000 monk seals were distributed among 13 colonies across the Caribbean. The biomass of reef fishes and invertebrates required to support historical seal populations was 732–1018 g m−2 of reefs, which exceeds that found on any Caribbean reef today and is comparable with those measured in remote Pacific reefs. Quantitative estimates of historically dense monk seal colonies and their consumption rates on pristine reefs provide concrete data on the magnitude of decline in animal biomass on Caribbean coral reefs. Realistic reconstruction of these past ecosystems is critical to understanding the profound and long-lasting effect of human hunting on the functioning of coral reef ecosystems

Cost of Federal tax credit programs to develop the market for industrial solar and wind energy technologies. Final report to Lawrence Livermore Laboratory, University of California. Volume 2: appendices

A study was made to estimate the impact tax credits (from Acts passed by Congress) would have on renewable energy investment and to estimate the net costs to the US Treasury of providing these tax credits. The appendices to this study are presented. Some investment and marketing penetration worksheets are presented on wind turbines, solar ponds, flat plates, evacuated tubes, and parabolic troughs. A market penetration and economic analysis program with test written for TI-59 programmable calculator with printer is presented. Data on the average $/kWh for each state are included for energy use (70 to 400/sup 0/F and electricity) and energy resource (total and direct solar and wind). Also included is an energy use processing program written for TI-59 programmable calculator with printer. (MCW