Prepared by the Arid Lands Information Center, Office of Arid Lands Studies, University of Arizona ; A. Paige Grant, compiler.

Prepared by the Arid Lands Information Center, Office of Arid Lands Studies, University of Arizona ; Robert G. Varady, compiler.

Prepared by the Arid Lands Information Center, Office of Arid Lands Studies, University of Arizona ; M. Justin Wilkinson, compiler.

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian declines around the world, including the southwestern United States. I studied patterns of Bd infection in Hyla arenicolor, Rana catesbeiana, and R. yavapaiensis in the Rincon Mountains and Tucson Basin in Arizona. Bd prevalence and infection intensity were location dependent in all species and R. yavapaiensis may be a reservoir of Bd for H. arenicolor, where they co-occurred. Treatment of a backyard population of R. yavapaiensis with itraconazole did not reduce winter frog mortality due to Bd. The lethal Bd infection threshold of this population was between 59,847 and 4,237,330 zoospores. Zoospore loads from swabs of freshly dead frogs did not differ significantly from those taken from those same frogs following freezing and thawing. Thus, important information regarding infection intensity and probable cause of death can be gathered from frogs collected by others and frozen until convenient to process.

Revised; Originally Published: 2004, 2006 / 106 pp.

No description available.

Este estudo tem como objetivo principal examinar se os recursos naturais considerados como bens de consumo ou fatores de produção, tem valor econômico e como este valor pode ser quantificado. Na primeira parte, fez-se uma revisão cronológica da literatura existente sobre o assunto, encontrando-se um grande número de estudos esparsos, relacionados de alguma forma com o tema da tese. Analogamente, procedeu-se a uma revisão conceitual e temática das principais escolas do pensamento econômico, com a finalidade de identificar as concepções dos autores e aproveitar os instrumentos já existentes relacionados à avaliação econômica dos recursos naturais. A seguir, procurou-se definir a melhor forma de analisar e avaliar os recursos naturais em relação ao consumo, produção e distribuição, e sob os aspectos estático e dinâmico. A partir desses cuidados, concluiu-se que os recursos naturais, quando quantificados como bens escassos, devem fazer jus a um valor econômico, para garantir o seu melhor uso e a sua conservação ao longo do tempo. Alicerçados nas considerações anteriores, passou-se a formalizar e a construir métodos para avaliar economicamente os principais recursos naturais, considerando e interpretando os antecedentes já disponíveis e, em algumas circunstâncias, fazendo propostas no sentido de como abordar estes assuntos. / This study's main objetive is to determine whether natural resources as consumer goods or factors of production, have economic value and how this value can be established. As a first step, a chronological revision of the existing literature on this issue was made, with a great number of studies found related, to a certain extent, to the topic of this thesis. Similarly, a revision of the main trends of economic thought was perfomed, aiming at identifying the author's ideas and at taking advantage of the existing methods related to the economic evaluation of natural resources. Next, an attempt was made to determine how to analyze and evaluate natural resource in relation to consumption, production and distribution, taking into account the static and dynamic aspects. Having these concerns in mind, the conclusion was the natural resources, when qualified as scarce goods, shold have an appropriate value so as to guarantee their best use and their conservation in the long run. Following these considerations, the last step was an attempt to formalize and set up methods to evaluate economically the main natural resources, taking into account and interpreting the available literature and, in some cases, makingproposals related to theses issues.

Digitized by Kansas Correctional Industries

No description available.

No description available.