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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
881

Top down and bottom up a comparison of nannofossil strontium/calcium and benthic foraminiferal accumulation rates as paleoproductivity indicators /

Waite, Amanda J. January 2005 (has links)
Thesis (M.S.)--University of Delaware, 2005. / Principal faculty advisor: Katharina Billups, Dept. of Marine and Earth Studies . Includes bibliographical references.
882

Variability of soil hydraulic properties and estimation of plant-available water on claypan-soil landscapes

Jiang, Pingping, January 2007 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 25, 2007) Vita. Includes bibliographical references.
883

Effects of species interactions and productivity on aquatic macroinvertebrate diversity and community composition in tree holes patterns and mechanisms /

Yee, Donald A. Juliano, Steven A. January 2006 (has links)
Thesis (Ph. D.)--Illinois State University, 2006. / Title from title page screen, viewed on May 14, 2007. Dissertation Committee: Steven A. Juliano (chair), Roger C. Anderson, L. Philip Lounibos, Wade A. Nichols, William L. Perry. Includes bibliographical references (leaves 145-162) and abstract. Also available in print.
884

An analysis of potential soil productivity and land use on the Standing Rock Reservation

Jeffery, Thomas C. January 1900 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed June 8, 2007). PDF text: iv, 100 p. : col. ill. ; 2.84 Mb. UMI publication number: AAT 3243739. Includes bibliographical references. Also available in microfilm and microfiche formats.
885

Can Patterns of Energetic Condition Explain Differences in the Productivity of Arctic and Common Terns at Petit Manan Island, Maine?

Agius, Stephen M. January 2008 (has links) (PDF)
No description available.
886

Active Hypothermic Growth: A Novel Means For Increasing Total Interferon-γ Production by Chinese Hamster Ovary Cells

Stephen R., Fox, Yap, Mei Xia, Yap, Miranda G.S., Wang, Daniel I.C. 01 1900 (has links)
When grown under hypothermic conditions, Chinese Hamster Ovary (CHO) cells become growth arrested in the G₀/G₁ phase of the cell cycle and also often exhibit increased recombinant protein production. In this study, we have validated this hypothesis by stimulating hypothermic growth using basic fibroblast growth factor and fetal bovine serum supplementation. This method led to 7.7- and 4.9-fold increase in total production compared to the 37°C and 32°C control cultures, respectively. This proof-of-concept study will motivate the creation of cell lines capable of growing at low temperatures for use in industrial processes. / Singapore-MIT Alliance (SMA)
887

Aggregate energy, efficiency and productivity measurement

Berndt, Ernst R. January 1978 (has links)
No description available.
888

Eficiência de fertilizantes fosfatados solúveis e pouco solúveis, com ou sem complexação com substâncias húmicas, em plantações de eucalipto / Efficiency of soluble and poorly soluble phosphate fertilizers, with or without complexation with humic substances, in Eucalyptus plantations

José Henrique Bazani 15 October 2014 (has links)
A fertilização tem proporcionado aumento de 30 a 50% da produtividade dos povoamentos de eucalipto, e tem no fósforo (P) um dos principais nutrientes responsáveis por estas respostas. Ambientes tropicais altamente intemperizados diminuem a disponibilidade do P no solo em função das reações de adsorção com os minerais de argila e precipitação com os cátions Fe, Al e Ca. O manejo adequado da fertilização fosfatada contribui para a otimização dos custos inerentes à atividade de fertilização e para manutenção da competitividade técnicofinanceira das plantações florestais. Diversas são as opções de fornecimento de P às plantas. Em geral, as fontes fosfatadas distinguem-se pela concentração, forma e solubilidade do P, mas apresentam a menor taxa de recuperação pelas plantas entre os macronutrientes. Novas tecnologias de fertilizantes fosfatados estão sendo desenvolvidas visando aumentar esta eficiência de utilização, as quais necessitam de validação e comprovação dos seus efeitos em condições reais de crescimento do povoamento. Uma alternativa para aumentar a eficiência do P é a complexação deste com substâncias húmicas (complexo P-metal-SH), pois podem diminuir os processos de adsorção e possibilitar o maior aproveitamento do nutriente. Constatou-se que é possível obter crescimento satisfatório do povoamento de Eucalyptus grandis apenas com a utilização de fontes fosfatadas totalmente solúveis, durante os dois primeiros anos de crescimento. Estas fontes tiveram efeito benéfico na sanidade e na uniformidade do povoamento. A utilização do fosfato natural reativo proporcionou comportamentos distintos no acúmulo de P nas plantas. Em condições de maior disponibilidade hídrica no solo, houve maior absorção de P pelas plantas relativamente ao período de maior limitação hídrica, fato que não foi observado com a utilização de fontes solúveis. O complexo P-metal-SH se mostrou uma alternativa tecnicamente viável, proporcionando oportunidades de ganho na eficiência de utilização do P e na produção de madeira. As respostas às diferentes fontes fosfatadas foram mais evidentes nos meses iniciais de crescimento do povoamento e diminuíram com o passar do tempo. Sob elevada deficiência hídrica do solo, esses efeitos foram menos pronunciados, em função da limitação do crescimento das plantas. Não houve grande diferença de crescimento das plantas em relação às fontes fosfatadas usadas, refletindo em oportunidades econômicas e logísticas que estão atreladas à escolha do fertilizante. Fontes de maior concentração possibilitam redução nos custos de formação do povoamento, em função da diminuição dos gastos com transporte e armazenamento, e permitem a obtenção de maiores rendimentos operacionais no momento da aplicação do fertilizante no campo. Contudo é preciso maior clareza quanto aos efeitos residuais da fertilização fosfatada, com suas diferentes fontes, nas rotações de cultivo subsequentes (em especial quanto ao manejo da talhadia). Estudos para entender a participação de formas de P presentes no solo não detectáveis nas análises de rotina (principalmente o P orgânico), no fornecimento de P às plantas, podem auxiliar os programas de fertilização a aperfeiçoar o uso do P em plantações florestais. / Fertilization has provided a 30-50% increase on Eucalyptus plantations productivity, and phosphorus (P) is one of the main nutrients responsible for this response. Highly weathered tropical soils reduce the availability of P applied during fertilization due to adsorption reactions with soil clay minerals and complexation with Fe, Al and Ca cations. Proper management of phosphate fertilization contributes to optimize the costs of fertilization and to maintain the economic competitiveness of forest plantations. There are several options for supplying P to plants. In general, phosphate sources differ in concentration, form and P solubility, however exhibit the lowest recovery rate by plants among the macronutrients. New technologies of phosphate fertilizers are being developed to increase this efficiency, which need validation and evidences of its effects on real growth conditions. An alternative to increase P efficiency is complexation with humic substances (P-metal-HS complex), once this method decreases the adsorption processes and provides a better utilization of this nutrient. This study showed a satisfactory growth of Eucalyptus grandis plantation only with the use of fully soluble phosphorus sources during the first two years of the stand. These sources positively affected healthiness and uniformity of the stand. The use of natural reactive phosphate caused different behaviors on P accumulation in plants. With high soil water availability there was a higher P uptake by plants compared with water limitation periods, this fact that was not observed when soluble sources were used. The P-metal-HS complex proved to be a technically feasible alternative to increase P utilization and wood production. The responses to the different phosphorus sources were more evident during the early months of forest growth and decreased over time. Under high soil water stress, these effects were lower due to plant growth limitation. There were no great differences on plant growth in relation to the phosphate sources used, what raises economic and logistic opportunities concerning to the fertilizer choice. Fertilizers with higher concentration sources decrease the initial costs of forest plantations as a result of reduction in expenses with transportation, storage and also due to better efficiency during fertilizer application on the field. However it is necessary to understand the residual effects of P fertilization, with different sources, on subsequent rotations (mainly regarding the coppice management). Studies to understand the participation of P forms in the soil, not detectable in routine analysis (especially organic P), on P supply to plants, can help fertilization programs to optimize the use of P in forest plantations.
889

Hétérogénéité des peuplements forestiers et production : interactions avec les traits fonctionnels des espèces / Heterogeneity of forest stands and productivity : interactions with functional traits of species

Bourdier, Thomas 20 October 2016 (has links)
La relation diversité-productivité est au cœur des enjeux actuels dans de nombreux écosystèmes. Dans l’étude de cette relation en peuplements forestiers, un aspect de la diversité a été longtemps négligé : l’hétérogénéité des tailles. Nous nous intéressons à l’effet de l’hétérogénéité des tailles sur la production en peuplements purs et mélangés et à ses interactions avec les traits fonctionnels des espèces. L’utilisation de données de l’inventaire forestier national nous a permis de démontrer un effet globalement négatif de l’hétérogénéité des tailles en peuplements purs de différentes espèces ainsi qu'en peuplements mélangés. Dans ce dernier cas, nous avons mis en évidence un effet positif sur la production de la richesse spécifique et un effet positif d’une diminution de la tolérance à l’ombre avec la taille des arbres c’est à dire lorsque les espèces les moins tolérantes dominent la canopée. Nous discutons les intérêts et limites de de ces résultats et leurs conséquences à plus ou moins long terme pour la stabilité et la résilience des peuplements forestiers. / Understanding the link between diversity ecosystem functioning has been a major topic of ecology for the last decades. When studying the relationship between diversity and productivity in tree populations and communities, size heterogeneity has often been disregarded. Our study focuses on the effect of size heterogeneity on the production of pure and mixed forest stands as wells its interactions with species’ functional traits. By using national forest inventory data, we were able to demonstrate a negative effect of size heterogeneity in both pure and mixed stands. In the latter case, we showed a positive effect of species richness as well as a positive effect of a decrease of shade tolerance with tree size, i.e. when the less tolerant species are dominant in the overstorey. We propose potential mechanisms to explain our results and discuss the consequences of such findings at larger time scale for the stability and resilience of forest stands.
890

As políticas industriais e a produtividade brasileira a partir dos anos 2000 : uma análise heterodoxa

Rocha, Carolina Silvestri Cândido January 2018 (has links)
Pode-se posicionar, atualmente, a produtividade como um dos temas mais intrigantes e relevantes da atualidade. Os debates que a circundam vão desde a maneira mais adequada de mensurá-la até seus condicionantes macro e microeconômicos. O cenário brasileiro atual outorga-lhe relevância ainda maior, uma vez que o país passa por um longo período de avanços muito modestos em termos de produtividade. As relações existentes entre produtividade industrial e inovação são descritas amplamente pela literatura econômica. A experiência dos países que caminharam em direção a níveis expressivamente superiores de produtividade aponta a inovação como elemento central em suas estratégias de desenvolvimento, o que ratifica o vínculo existente entre estas duas variáveis. Ademais, a produtividade também deve responder positivamente a esforços direcionados no âmbito da Política Industrial, quando esta encontra-se endossada por política acessórias, entre elas a política macroeconômica. Observa-se, neste contexto, que a Política Industrial brasileira a partir dos anos 2000 pouco impactou a produtividade da indústria nacional. Destacam-se: i) a política macroeconômica contraditória; ii) a desconsideração do ambiente de mudanças em termos econômicos e tecno-produtivos; iii) as falhas de concepção e execução da Política Industrial; iv) e a institucionalidade incapacidade de promoção de adesão e engajamento do setor produtivo como principais motivos para tal. / Nowadays, the productivity can be analyzed as one of the most relevant themes of the economics agenda. The debates that surround it go from the most appropriate way of measuring it to its macro and microeconomic constraints. The current Brazilian scenario provides it even greater relevance as the country goes through a long period of very modest advances in terms of productivity. The relation between industrial productivity and innovation are widely described in the economic literature. The experience of countries that have moved towards significantly higher levels of productivity points to innovation as a central element in their development strategies, which ratifies the linkages between these two variables. In addition, productivity must also respond positively to efforts directed into the scope of the Industrial Policy, when it is supported by ancillary policy, among them the macroeconomic policy. It is observed, in this context, that the Brazilian Industrial Policy from the 2000s had little impact on the productivity of the national industry. The following stand out because of the: i) contradictory macroeconomic policy; ii) misunderstanding of the environment for changes in economic and techno-productive terms; iii) failures to design and implement of the Industrial Policy; iv) and the institutionality inability to promote adherence and engagement of the productive sector as main reasons for doing so.

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