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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.
1

Optimalizace digitální podoby říční sítě a její dopad na vodohospodářský management povodí / Optimization of digital river network and its impact on catchment water management

Hošek, Zdeněk January 2016 (has links)
Digital river network dataset is an important source of information in any aspect of water management decision making. It is also a base for modelling or scientific research in many different fields. Development of the dataset in the Czech Republic had been fragmented in a past and as a result three different datasets have been developed that cover the whole of the state's territory. The datasets contain different geometries, different and often conflicting attributes and serve different purposes. Today the time has come that water management decision makers have realised that the situation is no longer sustainable and make effort to merge the datasets into one. The task brings in several technical issues and a potential for severe legal consequences. The aim of this study is to develop a methodological approach to merging the existing datasets into one. This methodological approach to decision which of the conflicting or different attributes should be adopted is based on assumption that the existing datasets will be merged into one consisting the best of all. Comparison of features in the existing dataset will inevitably lead to many conflicts when it will be necessary to decide which of the considered features should be adopted to the resulting dataset. The study considers the main purposes which...
2

Η διερεύνηση των μετεωρολογικών παραμέτρων και η προσέγγιση του υδρολογικού ισοζυγίου στην ευρύτερη περιοχή της λεκάνης του ποταμού Κόσυνθου, στο Νομό Ξάνθης

Μαυραποστόλου, Σοφία 01 October 2012 (has links)
Σκοπός της παρούσας εργασίας είναι η διερεύνηση των Μετεωρολογικών Παραμέτρων και η προσέγγιση του Υδρολογικού Ισοζυγίου στην ευρύτερη περιοχή της λεκάνης του ποταμού Κόσυνθου, στον Νομό της Ξάνθης. Για να συμβεί αυτό πρέπει να γίνει γνωστή η γεωμετρία του υδρολογικού συστήματος που μελετάται και οι παράμετροι, οι οποίες λαμβάνουν μέρος στο υδρολογικό ισοζύγιο. Προσεγγίζοντας και διερευνώντας αυτές τις παραμέτρους προσπαθούμε να καταρτίσουμε αντιπροσωπευτικά ισοζύγια κατά λεκάνη. / -
3

Caracterização hidrica de duas bacias hidrograficas de floresta urbana / Hydrological characterization of two watersheds in an urban forest

Guirao, Ângela Cruz, 1985- 15 August 2018 (has links)
Orientador: Jose Teixeira Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-15T22:48:02Z (GMT). No. of bitstreams: 1 Guirao_AngelaCruz_M.pdf: 47367371 bytes, checksum: 79d26a47051391bfa245e793ed78ad25 (MD5) Previous issue date: 2010 / Resumo: Este trabalho avaliou os efeitos resultantes do uso e ocupação da terra sobre os recursos hídricos. Foram estudadas duas bacias hidrográficas de floresta urbana, na Área de Relevante Interesse Ecológico Mata de Santa Genebra (MSG), Campinas (SP). A primeira bacia hidrográfica (B1) é coberta por uma pequena porção de área urbana (1,6ha) e o restante por floresta (28,6ha); a segunda bacia (B2) possui trechos de cultivo agrícola, predominando a cana-de-açúcar (62ha) e por floresta (162ha). Foi realizada a caracterização hídrica destas bacias, durante o período de um ano (2009), por meio dos seguintes instrumentos: levantamento das características físicas, cálculo do balanço hídrico e avaliação da carga de fósforo total como indicador da qualidade da água. Concluiu-se que predominam nas duas bacias os solos latossolos vermelhos, os tipos de relevos são os planos e suaves ondulados e as colinas médias prevalecem entre os tipos de terreno. Em relação ao balanço hídrico, a precipitação incidente total foi 1.491,8mm, sendo que desse total, 71% atravessou a vegetação e atingiu o solo em B1 e 29% foi interceptado; em B2, a precipitação interna foi maior 74,1% e foram interceptados pela cobertura vegetal, 25,9% O escoamento superficial em B1 foi 5,2% e em B2, 6,5% em relação à precipitação incidente, portanto, atribuiuse às perdas por transpiração e infiltração, em B1 e B2, 65,9 e 67,5%, respectivamente. A concentração de fósforo em B2 foi superior a B1, sendo 1,60mg/l na bacia com cana-de-açúcar. A carga de fósforo total somente foi possível calcular em B2, cujo total foi 2998,2mg/mm e a carga de chuva de fósforo, ou seja, o fósforo acumulado na vegetação e carregado até o solo pela chuva, para B2 foi de 6204kg. Estes resultados, confrontados com a literatura sobre o assunto e com o histórico e o atual uso e ocupação da terra no entorno da MSG, indicam que o entorno está alterando a qualidade e a quantidade dos recursos hídricos nestas bacias / Abstract: This study evaluated the effects of the use and occupation of land on water resources. Two watersheds of urban forests in the Area of Relevant Ecological Interest Mata de Santa Genebra (MSG), Campinas (SP) were studied. The first watershed (B1) is occupied by a small portion of urban area (1.6 ha) and the rest is by forest (28.6 ha). The second watershed (B2) is partially occupied by agriculture, predominantly sugar cane (62ha) and partially by the forest (162ha). It was done the hydrological characterization of this two watersheds during the period of one year (the year of 2009), through the following instruments: a survey of the physical characteristics, water balance calculation and evaluation of the load of total phosphorus as an indicator of water quality. It was concluded that oxisols soils are predominant in those two watersheds, the types of relief are flat, smooth and rolling average hills are prevalent among all types of terrain. About the water balance, the total incident precipitation was 1491.8 mm, and of this total, 71% acrossed the vegetation and reached the ground of B1 and 29% were intercepted. In B2, the throughfall was higher, 74.1% and it was intercepted by vegetation in 25.9%. The runoff in B1 was 5.2% and in B2, 6.5% of the incident precipitation, therefore, it was attributed to the losses by transpirationand other, 65.9% and 67.5%, respectively. The total phosphorus concentration in B2 was higher than in B1, it was 1.60 mg/l in the watershed with cane sugar. The load of total phosphorus was only possible to calculate in B2, whose total was 2998.2 mg/mm of rain and the load of phosphorus, or phosphorus accumulated in vegetation and loaded up to the soil by rain, in B2 was 6204 kilograms. These results confronted with the literature about this subject and the history and current use and occupancy of the land surrounding the MSG, this indicates that the environment is changing the quality and quantity of water in these watersheds / Mestrado / Análise Ambiental e Dinâmica Territorial / Mestre em Geografia
4

Respostas fisiológicas envolvidas na tolerância à restrição hídrica e estresse luminoso em Orchidaceae epífitas

Joca, Thais Arruda Costa January 2020 (has links)
Orientador: Luiz Fernando Rolim de Almeida / Resumo: Orquídeas epífitas estão expostas a diferentes microclimas, que são caracterizados pela alta irradiância imposta ao dossel e baixa irradiância em plantas situadas no sub-bosque. Além disso, este grupo de plantas frequentemente lida com a restrição hídrica. Na produção comercial, o estabelecimento de orquídeas é em quase sua totalidade limitada pela distribuição e intensidade destes mesmos fatores disponibilizados em casas de vegetação. Gomesa flexuosa Sims e Oncidium sphacelatum Lindley pertencem à subtribo Oncidiinae, e quando hibridizadas dão origem a O. ‘Aloha’ (uma orquídea CAM facultativa e importante híbrida comercial). O objetivo deste estudo foi elucidar a performance fotossintética e as estratégias de balanço hídrico de G. flexuosa e O. sphacelatum sob condições de estresse hídrico e luminoso, focando tanto nas diferenças interespecíficas como nas funções dos diferentes órgãos em um mesmo indivíduo. Para isso, analisamos trocas gasosas, fluorescência da clorofila a, quantificação de lipoperóxidos, discriminação isotópica, acidez titulável, conteúdo relativo de água e potencial hídrico em tecidos foliares, de pseudobulbos e raízes, em diferentes tratamentos envolvendo restrição hídrica e variação luminosa. Depois de restrição hídrica por 60 dias, G. flexuosa apresentou conversão de metabolismo C3 para CAM, o que deu subsídios para uma melhor performance das trocas gasosas, fluorescência da clorofila a, mecanismo de fotoproteção e relações hídricas. Quando submetida a ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Epiphyte orchids are exposed to different microclimates, which are characterized by high irradiance imposed on the canopy and low irradiance in plants located on the understory. In addition, this group of plants frequently deals with water restriction. In commercial production, the distribution and intensity of these same factors inside the greenhouses also limit the orchids establishment. Gomesa flexuosa Sims and Oncidium sphacelatum Lindley are Oncidiinae species and when hybridized, it gave origin to O. ‘Aloha’ (a facultative CAM orchid and na important commercial hybrid). The aim of this study was to elucidate the photosynthetic performance and the water balance strategies of G. flexuosa and O. sphacelatum under water and light stress conditions, focusing on an interspecific diferences as well as on different organs functions in the same individual. For that, we analyzed the gas exchange, chlorophyll a fluorescence, lipoperoxides quantification, isotopic discrimination, titratable acidity, water relative content and water potential of leaf, pseudobulb and root tissues in different treatments involving water restriction and light variation. After 60 days of water restriction, G. flexuosa converted the photosynthetic metabolism from C3 to CAM, which provided a better performance on gas exchanges, chlorophyll a fluorescence, photoprotection mechanism and water relations. When G. flexuosa was submitted to two events of water restriction, it showed a capacity to store informat... (Complete abstract click electronic access below) / Doutor
5

'Biogeographic Evolution of Madagascar's Microendemic Biota' : analyse et déconstruction / 'Biogeographic evolution of Madagascar's microendemic Biota' : analysis and deconstruction

Wilmé, Lucienne 17 September 2012 (has links)
Les oscillations paléoclimatiques au cours du Pléistocène et leur influence sur les bilans hydriques stationnels ont été considérées à Madagascar. La disponibilité en eau est l'élément majeur de la vie végétale et animale. À partir de travaux publiés en 2006, un modèle intégrant des aspects écologiques et géomorphologiques dans un contexte de changement climatique est considéré pour identifier les régions qui pouvaient présenter un bilan hydrique stationnel positif, indispensable à la survie de la faune et de la flore sylvicoles au cours des périodes les plus sèches, et l’évolution de ce bilan lorsque le climat redevenait chaud et humide. Le modèle a été appliqué à la biogéographie des lémuriens de Madagascar, et plus particulièrement à une région sédimentaire du versant occidental de l’île, pour expliquer le centre d’endémisme du Menabe Central, entre les bassins versants des fleuves Tsiribihina et Mangoky. / Pleistocene paleoclimatic oscillations have had a major influence on the hydrological balance in Madagascar, from the scale of individual sites to watersheds. Water availability is one of the major component for the life of plants and animals life. Based on previous research published in 2006, a model is considered which has been enriched, and encompasses ecological and geomorphological features in the context of changing climate to identify areas where water remained available during the driest periods, but also how availability increased again when climatic conditions become warmer and wetter. This model is applied to a portion of Western Madagascar encompassing the Tsiribihina and Mangoky watersheds and the Central Menabe center of endemism to describe the mechanism leading to landscape-Level evolution and especially the distribution patterns observed today of some of the island’s endemic animal species, comparing narrowly vs. broadly endemic taxa.

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