Thesis (M.A.--Urban and Environmental Policy)--Tufts University, 1992. / Cover title. "November 1992." Includes bibliographical references (p. 85-88).

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Orientador: Leonardo Fernandes Fraceto / Banca: Hudson Wallace Pereira de Carvalho / Banca: Daniel Junior de Andrade / Banca: Halley Caixeta de Oliveira / Banca: Marystela Ferreira / Resumo: Os artrópodes tem sido uma das principais causas de perdas agrícolas em todo o mundo. Só no Brasil essas perdas podem chegar a 7,7 % ao ano. A utilização extensiva de pesticidas sintéticos tem sido a principal forma de controle deste tipo de praga, no entanto, os efeitos adversos destes compostos tanto para o meio ambiente quanto para a saúde humana tem motivado a busca por alternativas menos impactantes. Neste contexto, diversos mecanismos estão sendo estudados a fim de minimizar estes danos, como por exemplo, o desenvolvimento de sistemas de liberação modificada, utilizando polímeros biodegradáveis e proteínas. Aliado a isto, a utilização de pesticidas botânicos também tem demostrado potencialidade para o combate a essas pragas, devido aos menores impactos causados por esses produtos de origem natural. Portanto, o presente trabalho apresenta o desenvolvimento (preparo e caracterização) de sistemas nanocarreadores produzidos a partir dos polímeros quitosana e goma arábica e da proteína zeína para os compostos botânicos (geraniol, citronelal, eugenol e cinamaldeído), bem como, os potenciais efeitos cito e fitotóxicos destes sistemas. Ademais foram também realizados ensaios de atividade biológica destes sistemas em pragas agrícolas (mosca-branca, ácaro-rajado e lagarta falsamedideira). Os compostos botânicos apresentaram elevada eficiência de encapsulação em ambos os sistemas carreadores, sendo que os sistemas foram capazes de proteger os compostos contra uma degradação premat... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Arthropods have been a major cause of agricultural losses worldwide. Only in Brazil can these losses reach 7.7% per year. The extensive use of synthetic pesticides has been the main form of control of this type of pest, however, the adverse effects of these compounds for both the environment and human health have motivated the search for less impactful alternatives. In this context, several mechanisms are being studied in order to minimize these damages, such as the development of modified release systems using biodegradable polymers and proteins. In addition to this, the use of botanical pesticides has also shown potential for combating these pests, due to the lower impacts caused by these products of natural origin. Therefore, the present work showed the development (preparation and characterization) of nanocarrier systems produced from chitosan and gum arabic polymers and zein protein for the botanical compounds (geraniol, citronellal, eugenol and cinnamaldehyde), as well as the potential effects and phytotoxic systems. In addition, tests of the biological activity of these systems on agricultural pests (whitefly, two-spotted spider mite and soybean looper) were also carried out. The botanical compounds showed high encapsulation efficiency in both carrier systems, and the systems were able to protect the compounds against premature degradation and also against ultraviolet radiation. The phyto and cytotoxicity results showed that encapsulation decreased the toxic effect of ... (Complete abstract click electronic access below) / Doutor

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Thesis (M. Com. (Agr.)) -- Lincoln University, 2009. / Also available via the World Wide Web.

Small-scale, conservation-based agrarianism provides a model for sustainable human habitation within heterogeneous landscapes. Thoreau's Transcendentalism and the historical roots of American Agrarianism are explored as influences for wilderness preservation and the New Agrarian movement. Idealizing a distant wilderness too often means overlooking the ecological and socio-economic environment where people live. Middle landscapes between nature and culture, or between wilderness and cities, can either increase or reduce ecological and social functioning within the landscape matrix. Managing middle landscapes by agrarian principles helps move both nature and culture towards ecological, economic, and social sustainability. This thesis ends with a discussion of agrarian themes, such as supporting decentralized local economies and increasing community connectivity, applied in urban, rural, and wilderness landscapes.

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Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains vii, 67 p. Vita. Includes abstract. Includes bibliographical references (p. 50-51).

The aim of the thesis is to investigate the barriers to, and the driver of, the adoption of organic agriculture, especially from the point of view of agricultural professionals (scientists, researchers, academics and extension officers). The thesis also summarises the economics of organic agriculture, and provides a unique case study on organic viticulture in Foster's Clare Valley Estare from the 1980s to mid 2000. / Thesis (PhD)--University of South Australia, 2006.

Thesis (B.A. Hons.)--Murdoch University, Perth, 2001. / Title from title page (viewed on 8 Sept. 2004). Includes bibliographical references.