Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Context (language use). The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

GTAP-E: An Energy-Environmental Version of the GTAP Model

Abstract: Energy is an important commodity in many economic activities. Its usage affects the environment via CO2 emissions and the Greenhouse Effect. Modeling the energy-economy-environment-trade linkages is an important objective in applied economic policy analysis. Previously, however, the modeling of these linkages in GTAP has been incomplete. This is because energy substitution, a key factor in this chain of linkages, is absent from the standard model specification. This technical paper remedies this deficiency by incorporating energy substitution into the standard GTAP model. It begins by first reviewing some of the existing approaches to this problem in contemporary CGE models. It then suggests an approach for GTAP which incorporates some of these desirable features of energy substitution. The approach is implemented as an extended version of the GTAP model called GTAP-E, which includes the standard GTAP model as a special case. In addition, GTAP-E incorporates carbon emissions from the combustion of fossil fuels and this revised version of GTAP-E provides for a mechanism to trade these emissions internationally. The resulting behavior of agents in the model is analyzed using general equilibrium demand elasticities which summarize the combined effect of the new model specification. Implications for policy analysis are demonstrated via a simple simulation experiment in which global carbon emissions are reduced via a carbon tax. Results show that incorporating energy substitution into GTAP is essential for conducting analysis of this problem. The policy relevance of GTAP-E in the context of the existing debate about climate change is illustrated by some simulations of the implementation of the Kyoto Protocol. It is hoped that the proposed model will be used by individuals in the GTAP network who may not be themselves energy modelers, but who require a better representation of the energy-economy linkages than is currently offered in the standard GTAP model.

Scavenging by vertebrates: behavioral, ecological, and evolutionary perspectives on an important energy transfer pathway in terrestrial ecosystems

Abstract: Carrion use by terrestrial vertebrates is much more prevalent than conventional theory implies, and, rather than a curiosity of animal behavior, is a key ecological process that must be accounted for. Human aversion to rotted substances and difficulties associated with identifying scavenged material in studies of food habits have contributed to the relative lack of information concerning scavenging behavior in vertebrates. Several lines of evidence, however, suggest that carrion resources are more extensively used by vertebrates than has been widely assumed: 1) a substantial number of animals die from causes other than predation and become available to scavengers, 2) a wide variety of vertebrate scavengers, rather than microbes or arthropods, consume most available carcasses, and 3) intense competition exists between vertebrate scavengers and decomposers, especially in warm climates. Although vultures are best adapted to use carrion, nearly all vertebrate predators are also scavengers to some extent. The costs and benefits associated with carrion use influences the evolution of scavenging behavior in vertebrates, resulting in a continuum of facultative scavengers that use carrion to varying degrees. The realized usage of carrion by a vertebrate species is influenced by the speed and efficiency with which it forages, its visual and olfactory abilities, and its capacity for detoxifying products of decomposition. A deeper understanding of carrion use by facultative scavengers will improve our knowledge of community and ecosystem processes, especially the flow of energy through food webs.

Tissue graft composition

Abstract: This invention relates to a method for preparation of a tissue graft composition from a segment of small intestine. A tissue graft composition is described which comprises the tunica submucosa of a segment of small intestine of a warm-blooded vertebrate wherein the tunica submucosa is deliminated from the tunica muscularis and at least the luminal portion of the tunica mucosa. The tissue graft composition has been shown to have excellent mechanical characteristics, as well as non-allergenicity and non-thrombogenicity in applications as vascular autografts, vascular allografts, and vascular heterografts.