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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.
51

Padrão de sobreposição e co-ocorrência interespecífica de moscas-das-frutas (Diptera, Tephritidae, Anastrepha) em áreas antropizadas / Overlap pattern and interespecific co-ocurrence of fruit flies (Diptera, Tephritidae, Anastrepha) in anthropic areas

Amaral, Tayron Sousa 11 March 2014 (has links)
O padrão de sobreposição de nicho e a co-ocorrência, bem como as interações positivas e negativas entre espécies de Anastrepha, com base em matrizes com dados de abundância e presença-ausência, foi avaliado. As populações de Anastrepha foram estudadas também quantativamente para avaliar sua distribuição e a flutuação populacional das espécies predominantes. O estudo foi realizado em duas áreas antropizadas, denominadas Fazenda Areão e Monte Olimpo, do campus \"Luiz de Queiroz\", Universidade de São Paulo, Piracicaba, SP. O estudo foi baseado em 52 coletas por meio de 14 armadilhas tipo McPhail distribuídas nas duas áreas. Foram coletadas 1.583 fêmeas pertencentes a 14 espécies: A. amita Zucchi, A. barbiellinii Lima, A. bistrigata Bezzi, A. daciformis Bezzi, A. distincta Greene, A. fraterculus (Wiedemann), A. grandis (Macquart), A. manihoti Lima, A. montei Lima, A. obliqua (Macquart), A. pickeli Lima, A. pseudoparallela (Loew), A. serpentina (Wiedemann) e A. sororcula Zucchi. Na Fazenda Areão, foram coletadas mais espécimes (1.041), em comparação ao Monte Olimpo (542), que, entretanto, apresentou o maior índice de diversidade de espécies. Anastrepha fraterculus, A. obliqua e A. pseudoparallela foram predominantes na Fazenda Areão; no Monte Olimpo, apenas A. fraterculus e A. pseudoparallela foram predominantes. A média de sobreposição de nicho foi maior que o esperado ao acaso para as duas áreas, portanto, os nichos ecológicos das espécies, em grande parte, se sobrepõem. O padrão de co-ocorrência indicou a ocorrência de dois pares de espécies não aleatórios que segregaram: A. pseudoparallela x A. obliqua na Fazenda Areão e A. fraterculus x A. pseudoparallela no Monte Olimpo. A segregação indica que pode haver competição por algum recurso dentro do nicho. A análise também apresentou três pares agregados: A. bistrigata x A. montei e A. fraterculus x A. barbiellinii para a Fazenda Areão e A. fraterculus x A. bistrigata para o Monte Olimpo, indicando que cada par coexiste pacificamente, sem que haja interferência na permanência das populações de moscas-das-frutas nas áreas. O nível populacional mais elevado ocorreu de agosto a dezembro, nas duas áreas, quando as temperaturas oscilaram entre 18 e 24°C, com pico populacional em setembro. / The niche overlap pattern and co-ocurrence, as well as positive and negative interactions among Anastrepha species, based on abundance matrix data and presence-absence data was evaluated. The populations of species of Anastrepha was analyzed quantitatively to evaluate its distribution and the populational fluctuation of predominant species. The study was carried out in two anthropic areas, Fazenda Areão and Monte Olimpo, at \"Luiz de Queiroz\" campus, Universidade de São Paulo, Piracicaba, SP. The research was based on 52 samplings obtained over 14 McPhail traps distributed in these two areas. It was captured 1,583 females belong 14 species: A. amita Zucchi, A. barbiellinii Lima, A. bistrigata Bezzi, A. daciformis Bezzi, A. distincta Greene, A. fraterculus (Wiedemann), A. grandis (Macquart), A. manihoti Lima, A. montei Lima, A. obliqua (Macquart), A. pickeli Lima, A. pseudoparallela (Loew), A. serpentina (Wiedemann) and A. sororcula Zucchi. It was collected more specimens (1,041) at Fazenda Areão, comparing with the ones at Monte Olimpo (542), that showed the highest species diversity index. Anastrepha fraterculus, A. obliqua and A. pseudoparallela were the predominant species at Fazenda Areão; at Monte Olimpo, only A. fraterculus and A. pseudoparallela were predominant. The niche overlap mean was higher than randomly expected for these two areas. Therefore, the species ecological niches mostly overlap. The coocurrence pattern indicated the ocurrence of two non-randomized pair of species that segregated: A. pseudoparallela x A. obliqua at Fazenda Areão, and A. fraterculus x A. pseudoparallela at Monte Olimpo. The segregation indicates that can exist three aggregated pairs: A. bistrigata x A. montei and A. fraterculus x A. barbiellinii at Fazenda Areão; and A. fraterculus x A. bistrigata at Monte Olimpo, indicating that each pair coexists pacifically, with no interference in the permanence of the fruit fly populations in the areas. The highest populational level occurred from August to December, when temperatures oscillated between 18 and 24°C, with the population peak in September.
52

Evaluation of the applicability of diatom based indices as bioindicators of water quality in South African rivers / Pieter Arno de la Rey.

De la Rey, Pieter Arno January 2008 (has links)
Diatoms have been proven to be reliable indicators of water quality in many countries of the world particularly Europe. The potential use of diatoms as indicators of water quality in South Africa was tested in the studies in this document. This study evaluates the potential use of diatom based indices by testing it against a macroinvertebrate index (SASS 5) and evaluating the variation in the index scores of the two indices due to changes in chemical water quality and habitat. It was concluded that the diatom monitoring system performs well as bioindicator of water quality. It was also concluded that it should be used as a complementary system to the much used SASS 5 invertebrate index. This conclusion was made due to the fact that diatoms react more directly to changes in water quality than macroinvertebrates (SASS 5), and macroinvertebrates react more readily to changes in habitat than diatoms. A further part of the study was to assess whether aut-ecological or diversity based diatom indices performed best in South African conditions. This study found that the ecological indices were more sensitive to changes in water quality than the diversity indices. The diatom based indices that performed best as water quality indicators were the specific pollution sensitivity index (SPI) and the biological diatom index (BDI). A standard method for the sampling, preparation and enumeration for diatoms to be used for index score generation is also suggested to ensure the comparability of diatom based index data to facilitate use of such bio monitoring data for management purposes. The main focus of the study was to eliminate some of the obstacles for the use of diatoms as bio indicators of water quality in South Africa. It is believe that this aim has been accomplished in the study. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2008.
53

Evaluation of the applicability of diatom based indices as bioindicators of water quality in South African rivers / Pieter Arno de la Rey.

De la Rey, Pieter Arno January 2008 (has links)
Diatoms have been proven to be reliable indicators of water quality in many countries of the world particularly Europe. The potential use of diatoms as indicators of water quality in South Africa was tested in the studies in this document. This study evaluates the potential use of diatom based indices by testing it against a macroinvertebrate index (SASS 5) and evaluating the variation in the index scores of the two indices due to changes in chemical water quality and habitat. It was concluded that the diatom monitoring system performs well as bioindicator of water quality. It was also concluded that it should be used as a complementary system to the much used SASS 5 invertebrate index. This conclusion was made due to the fact that diatoms react more directly to changes in water quality than macroinvertebrates (SASS 5), and macroinvertebrates react more readily to changes in habitat than diatoms. A further part of the study was to assess whether aut-ecological or diversity based diatom indices performed best in South African conditions. This study found that the ecological indices were more sensitive to changes in water quality than the diversity indices. The diatom based indices that performed best as water quality indicators were the specific pollution sensitivity index (SPI) and the biological diatom index (BDI). A standard method for the sampling, preparation and enumeration for diatoms to be used for index score generation is also suggested to ensure the comparability of diatom based index data to facilitate use of such bio monitoring data for management purposes. The main focus of the study was to eliminate some of the obstacles for the use of diatoms as bio indicators of water quality in South Africa. It is believe that this aim has been accomplished in the study. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2008.
54

Bases para aplicação de índices biológicos no biomonitoramento de ambientes lóticos - comunidade bentônica / Bases for Biological Index use in lotic Environment Biomonitoring - Benthic Community

Helena Mitiko Watanabe 18 September 2007 (has links)
A utilização da comunidade bentônica em biomonitoramento, como indicadora da qualidade de ambientes aquáticos, encontra-se atualmente bem estabelecida. Das duas abordagens sugeridas pelo Protocolo de Avaliação Rápida da USEPA, a que utiliza um único meso-hábitat mostra-se ideal para o biomonitoramento sendo, portanto, necessário estabelecer qual meso-hábitat utilizar. Este trabalho pretende avaliar a sensibilidade e adequabilidade de diferentes meso-hábitat ribeirinhos em biomonitoramento. Foram estabelecidos oito pontos de amostragem, localizados nos rios Atibainha, Cachoeira e Atibaia, na Bacia Hidrográfica do Rio Piracicaba, São Paulo. Amostras foram coletadas na estação chuvosa (março), para análise de variáveis ambientais (água e sedimento) e biótica (macroinvertebrados bentônicos). Os organismos da comunidade bentônica foram identificados ao nível de família para os principais taxa. Os dados ambientais e bióticos foram submetidos à análise de agrupamento e ordenação, e para o diagnóstico da qualidade do ambiente aquático, índices individualizados e abordagem multimétrica foram utilizados. Tanto as variáveis ambientais quanto a biótica separaram nitidamente regiões de alto (3ª e 4ª ordens) e baixo gradiente (5ª e 6ª ordens). Dos meso-hábitats analisados por meio da comunidade bentônica, apenas canal e margem deposicional mostraram-se promissores e destes, margem deposicional mostrou-se o mais adequado para biomonitoramento, tanto por discernir o gradiente de poluição existente quanto por possibilitar a avaliação integrada de variáveis bióticas, químicas e toxicológicas, o que minimizaria esforços com acréscimo de informações. / The use of benthic communities in biomonitoring, as indicator of aquatic environmental quality is currently well established. Considering the two approaches suggested by Rapid Assessment Protocol of US-EPA, the single mesohabitat approach is ideal for the practical purposes of biomonitoring, being hence necessary to establish which meso-habitat to use. This paper aims to evaluate the sensitivity and suitability of different river meso-habitats for biomonitoring. Eight sampling sites were established along Atibainha, Cachoeira and Atibaia Rivers, in Piracicaba River basin, São Paulo State, Brazil. Sampling were carried out in rainy season (March) to evaluate environmental (water and sediment) and biotic (benthic macroinvertebrates) parameters. The major benthic taxa were identified to family level.. Environmental and biotic data were submitted to cluster and ordination analysis, and for the quality of aquatic environment diagnosis, individualized index and multimetrics approach were used. Both environmental and biotic parameters distinctly discriminated upper (3rd and 4th orders) from lower (5th and 6th orders) gradient regions. Among the meso-habitats analyzed by mean of the benthic community, only channel and depositional bank were promising and of the two, deposicional bank proved to be the most adequate for biomonitoring, both for discerning pollution gradient and for enabling an integrated assessment of biotic, chemical and toxicological parameters, minimizing efforts and adding information
55

Padrão de sobreposição e co-ocorrência interespecífica de moscas-das-frutas (Diptera, Tephritidae, Anastrepha) em áreas antropizadas / Overlap pattern and interespecific co-ocurrence of fruit flies (Diptera, Tephritidae, Anastrepha) in anthropic areas

Tayron Sousa Amaral 11 March 2014 (has links)
O padrão de sobreposição de nicho e a co-ocorrência, bem como as interações positivas e negativas entre espécies de Anastrepha, com base em matrizes com dados de abundância e presença-ausência, foi avaliado. As populações de Anastrepha foram estudadas também quantativamente para avaliar sua distribuição e a flutuação populacional das espécies predominantes. O estudo foi realizado em duas áreas antropizadas, denominadas Fazenda Areão e Monte Olimpo, do campus \"Luiz de Queiroz\", Universidade de São Paulo, Piracicaba, SP. O estudo foi baseado em 52 coletas por meio de 14 armadilhas tipo McPhail distribuídas nas duas áreas. Foram coletadas 1.583 fêmeas pertencentes a 14 espécies: A. amita Zucchi, A. barbiellinii Lima, A. bistrigata Bezzi, A. daciformis Bezzi, A. distincta Greene, A. fraterculus (Wiedemann), A. grandis (Macquart), A. manihoti Lima, A. montei Lima, A. obliqua (Macquart), A. pickeli Lima, A. pseudoparallela (Loew), A. serpentina (Wiedemann) e A. sororcula Zucchi. Na Fazenda Areão, foram coletadas mais espécimes (1.041), em comparação ao Monte Olimpo (542), que, entretanto, apresentou o maior índice de diversidade de espécies. Anastrepha fraterculus, A. obliqua e A. pseudoparallela foram predominantes na Fazenda Areão; no Monte Olimpo, apenas A. fraterculus e A. pseudoparallela foram predominantes. A média de sobreposição de nicho foi maior que o esperado ao acaso para as duas áreas, portanto, os nichos ecológicos das espécies, em grande parte, se sobrepõem. O padrão de co-ocorrência indicou a ocorrência de dois pares de espécies não aleatórios que segregaram: A. pseudoparallela x A. obliqua na Fazenda Areão e A. fraterculus x A. pseudoparallela no Monte Olimpo. A segregação indica que pode haver competição por algum recurso dentro do nicho. A análise também apresentou três pares agregados: A. bistrigata x A. montei e A. fraterculus x A. barbiellinii para a Fazenda Areão e A. fraterculus x A. bistrigata para o Monte Olimpo, indicando que cada par coexiste pacificamente, sem que haja interferência na permanência das populações de moscas-das-frutas nas áreas. O nível populacional mais elevado ocorreu de agosto a dezembro, nas duas áreas, quando as temperaturas oscilaram entre 18 e 24°C, com pico populacional em setembro. / The niche overlap pattern and co-ocurrence, as well as positive and negative interactions among Anastrepha species, based on abundance matrix data and presence-absence data was evaluated. The populations of species of Anastrepha was analyzed quantitatively to evaluate its distribution and the populational fluctuation of predominant species. The study was carried out in two anthropic areas, Fazenda Areão and Monte Olimpo, at \"Luiz de Queiroz\" campus, Universidade de São Paulo, Piracicaba, SP. The research was based on 52 samplings obtained over 14 McPhail traps distributed in these two areas. It was captured 1,583 females belong 14 species: A. amita Zucchi, A. barbiellinii Lima, A. bistrigata Bezzi, A. daciformis Bezzi, A. distincta Greene, A. fraterculus (Wiedemann), A. grandis (Macquart), A. manihoti Lima, A. montei Lima, A. obliqua (Macquart), A. pickeli Lima, A. pseudoparallela (Loew), A. serpentina (Wiedemann) and A. sororcula Zucchi. It was collected more specimens (1,041) at Fazenda Areão, comparing with the ones at Monte Olimpo (542), that showed the highest species diversity index. Anastrepha fraterculus, A. obliqua and A. pseudoparallela were the predominant species at Fazenda Areão; at Monte Olimpo, only A. fraterculus and A. pseudoparallela were predominant. The niche overlap mean was higher than randomly expected for these two areas. Therefore, the species ecological niches mostly overlap. The coocurrence pattern indicated the ocurrence of two non-randomized pair of species that segregated: A. pseudoparallela x A. obliqua at Fazenda Areão, and A. fraterculus x A. pseudoparallela at Monte Olimpo. The segregation indicates that can exist three aggregated pairs: A. bistrigata x A. montei and A. fraterculus x A. barbiellinii at Fazenda Areão; and A. fraterculus x A. bistrigata at Monte Olimpo, indicating that each pair coexists pacifically, with no interference in the permanence of the fruit fly populations in the areas. The highest populational level occurred from August to December, when temperatures oscillated between 18 and 24°C, with the population peak in September.
56

Índices químicos, sensoriais e microbiológicos para avaliação do frescor de pescada amarela (Cynoscion acoupa) armazenada em gelo / Chemical, sensory and microbial Indices for freshness evaluation of Acoupa weakfish (Cynoscion acoupa) stored in ice

Ana Paula Billar dos Santos 05 December 2011 (has links)
Os objetivos deste estudo foram desenvolver o protocolo do Método do Índice de Qualidade (MIQ) para avaliação da qualidade sensorial da pescada amarela parcialmente eviscerada e armazenada em gelo; avaliar as alterações sensoriais, químicas e microbiológicas da pescada amarela durante o armazenamento e indicar os parâmetros mais adequados para avaliação da qualidade propondo limites de aceitação para a espécie. Quatro lotes com peixes recém capturados em Praia Grande-SP foram transportados à Faculdade de Zootecnia e Engenharia de Alimentos (FZEA) e armazenados entre camadas de gelo (0-1ºC) em câmara fria. Periodicamente 5 peixes foram amostrados e submetidos às análises sensorial (para desenvolvimento do protocolo MIQ e posterior avaliação), microbiológicas (contagens de psicrotróficos, coliformes totais e fecais, Salmonella sp, estafilococos coagulase positiva) e químicas (bases nitrogenadas voláteis-BNV, trimetilamina-TMA, triptofano livre e uréia). A qualidade da pescada amarela comercializada em 14 pontos de venda nas cidades de Santos, São Vicente e Praia Grande foi avaliada utilizando-se o protocolo MIQ desenvolvido, análises microbiológicas e químicas. O protocolo MIQ desenvolvido apresentou aumento linear do índice de qualidade (IQ) ao longo do armazenamento. Nos peixes do lote 1, contagens de psicrotróficos atingiram 107ufc/g no 14º dia. Nos lotes 3 e 4 esse limite foi alcançado entre o 6º e 8º dia. Contagens de E.coli superiores a 102ufc/g foram observadas em 9,5% dos peixes do lote 1 após 21 dias de armazenamento e em 15,25% dos peixes do lote 3 no 6º e 9º dia. Staphylococcus aureus estava ausente em todos os peixes e Salmonella sp foi detectada foi detectada em 7,4% das pescadas amarelas analisadas. Os valores finais de BNV variaram de 23.8 mg/100g a 159 mg/100g em pescadas amarelas e foi dependente da carga microbiana inicial. Todos os lotes apresentaram aumento no teor de TMA, que variou entre 0,18 mg/100g e 15,44mg/100g. As amostras de pescada amarela comercializadas apresentaram IQ variando de 2 a 23, indicando um tempo provável pós captura de 3 até 14 dias. Todos os peixes analisados estavam livres de Salmonella sp e E.coli. Staphylococcus aureus foi determinado em níveis abaixo do limite estipulado pela legislação. Contagens de psicrotróficos acima de 107ufc/g foram observadas em 50% dos peixes. Coliformes totais variaram de 102ufc/g até 107ufc/g. Os valores de TMA e BNV foram maiores que os estabelecidos pela legislação brasileira em 50% e 65% dos peixes, respectivamente. No entanto, em relação à TMA, concentrações superiores a 4mg/100g foram encontradas em peixes que apresentaram contagens de psicrotróficos, concentração de BNV e IQ aceitáveis, sugerindo valores em torno de 12-14mg TMA/100g de peixe como limite adequado para consumo de pescada amarela O valor 30mg de BNV/100g recomendado pela legislação brasileira parece ser adequado como limite de comercialização de pescada amarela, porém a concentração de BNV não está diretamente relacionada ao tempo de armazenamento desde a captura. Triptofano livre e uréia não foram parâmetros químicos adequados para avaliação do frescor da pescada amarela. O protocolo MIQ foi eficiente para a avaliação da qualidade de pescada amarela, apresentando boa correlação entre a perda da qualidade sensorial e o tempo de estocagem. A análise de correlação entre os resultados das diversas análises sugere que a pescada amarela, quando eviscerada e resfriada em gelo, mantém características adequadas para consumo até o 8º dia de armazenamento. Diversos estabelecimentos comerciais de Santos, São Vicente e Praia Grande disponibilizam para os consumidores pescada amarela resfriada em condições inadequadas para consumo de acordo com a legislação brasileira. / The objectives of this study were to develop a Quality Index Method (QIM) scheme for sensory evaluation of partially gutted Acoupa weakfish; to evaluate the sensory, chemical and microbial changes during storage in ice and to suggest the best parameters for quality evaluation and limits of acceptability of this fish species. Four groups of Acoupa weakfish caught in Praia Grande, São Paulo state, were transported to the Faculdade de Zootecnia e Engenharia de Alimentos (FZEA) within 24h of their capture and stored between layers of ice (0-1ºC) in chilling room. Periodically, 5 fishes were sampled and evaluated by sensory (QIM), microbial (counts of psychrotrophic, total and faecal coliforms, Salmonella sp and coagulase-positive Staphylococcus) and chemical (volatile base nitrogen-VBN, trimethylamine-TMA, free tryptophan and urea) analysis. The quality of samples of Acoupa weakfish commercialized in fourteen markets in Santos, São Vicente and Praia Grande cities was also evaluated. The QIM scheme presented linear increase of QI during the storage. In fishes of group 1 the counts of psychrotrophic bacteria reached 107cfu/g at the 14th day of storage. In groups 3 and 4 this limit was reached between days 6 and 8. Counts of E. coli higher than 102cfu/g were detected in 9.5% of the fishes belonging to the group 1 after day 21. This level was also detected in 15.25% of the fishes of the group 3 after days 6 and 9. Staphylococcus aureus was not detected and Salmonella sp was present in 7.4% of the Acoupa weakfish in groups 1 and 2. VBN contents ranged from 23.8 mg/100g to 159 mg/100g and was affected by the microbial load at the beginning of the storage. All the groups of Acoupa weakfish in this study, presented increases in TMA contents during storage and the values ranged between 0.18 and 15.44mg/100g. The samples of Acoupa weakfish obtained from markets showed QI ranging from 2 to 23, suggesting a storage time between 3 to 14 days respectively. All the fishes were free from Salmonella sp and E. coli. Counts of Staphylococcus aureus were lower than the amount determined by the Brazilian legislation. Counts of psychrotrophic bacteria higher than 107cfu/g were observed in 50% of the fishes. Counts of total coliforms ranged from 102cfu/g till 107cfu/g. TMA and VBN contents were higher than the amount allowed by the Brazilian legislation in 50% and 65% of the fishes, respectively. Nevertheless, TMA contents higher than 4mg/100g, were detected in fishes presenting low counts of psychrotrophics, low VBN levels and low QI. Contents ranging from 12-14mg TMA/100g of fish are the suggested limits of consumption for Acoupa weakfish. The limit of 30mg of VBN/100g of fish, allowed by the Brazilian legislation is the appropriate amount for commercialization of Acoupa weakfish, although the VBN contents are not directly related to the storage time. Free tryptophan and urea were not useful as quality indices for Acoupa weakfish. The QIM scheme was effective for quality evaluation of Acoupa weakfish showing significant correlation with quality loss and storage time. Results of correlation analysis allow suggesting that Acoupa weakfish, when gutted and maintained in ice, is suitable for consuming until day 8. Several markets in Santos, São Vicente and Praia Grande commercialize chilled Acoupa weakfish that are unacceptable for consumption according to the Brazilian legislation.
57

Réalisation d'une plate-forme fondée sur la théorie de la décision, l'optimisationet la diffusion pour prévoir, modéliser et gérer une catastrophe naturelle : les feux de forêts / Realization of a framework based on decision theory, optimization and diffusion to predict, model and manage a natural disaster : forest fires

Karouni, Ali 03 October 2014 (has links)
Au cours des dernières décennies, le nombre d'occurrences de catastrophes naturelles a augmenté sensiblement. Cette augmentation a des conséquences catastrophiques sur les espaces verts, les propriétés et les êtres vivants. L'énorme quantité de dommages a attiré l'attention des chercheurs, des organisations et des secteurs gouvernementaux et non-gouvernementaux vers l'analyse de ces phénomènes, leurs causes et leurs effets. Le but est de pouvoir reconnaître leurs comportements et prédire leur occurrence pour mieux aborder la phase de gestion des risques qui contribue à empêcher leur incidence ou limiter les conséquences. Le risque de d'incendie existe souvent et la présence de dangers est également possible. D'où l'importance de tout effort pour lutter contre de telles crises. Dans cette contribution, le phénomène des incendies de forêt est étudié. Au Liban, les espaces verts ont considérablement diminué au cours des dernières années, ce qui impose une intervention urgente des politiques et le soutien des organisations gouvernementales et non gouvernementales. L'orientation globale est d’aller vers des techniques qui permettent de prédire les risques élevés d'incendie permettant ainsi de prendre des précautions pour empêcher les occurrences d'incendie ou tout au moins limiter leurs conséquences. La prévision des incendies de forêt contribue à prévenir d'une part la fréquence des incendies et d'autre part, à réduire ses impacts sur les êtres vivants, les propriétés et la richesse forestière.... / During the last decades, the number of occurrences of natural disasters has increased noticeably which lead to catastrophic results on human as well as properties and green areas. But despite the huge amount of damages, this helps to draw the attention of researchers, organizations and the various governmental and non-governmental sectors towards analyzing these phenomena, their causes & effects, allowing to recognize their behaviors and the methods to predict their occurrence and thus reaching the phase of risk management contributing to prevent their incidence or limit the consequences. As the risk of happening often exists, the instantaneous presence of dangers is also possible. Here appears the importance of any effort that serves to tackle such crises. In this contribution, the phenomenon of forest fires is studied. In Lebanon, green areas declined dramatically during the last decades, what imposes an urgent intervention with strict governmental policies and support of non-governmental organizations. The global orientation is towards techniques that predict high fire risks, allowing for precautions to preclude fire occurrences or at least limit their consequences. Forest fire prediction proves to contribute in preventing fire occurrence or reducing its catastrophic impacts in worst cases on human lives, properties and green forestry....
58

Analyse bayésienne de la gerbe d'éclats provoquée pa l'explosion d'une bombe à fragmentation naturelle / Bayesian analysis of the sheaf of fragments caused by the explosion of a natural fragmentation bomb

Gayrard, Emeline 14 November 2019 (has links)
Durant cette thèse, une méthode d'analyse statistique sur la gerbe d'éclats d’une bombe, en particulier sur leurs masses, a été mise au point. Nous avions à disposition trois échantillons partiels de données expérimentales et un modèle mécanique simulant l'explosion d'un anneau. Dans un premier temps, un modèle statistique a été créé à partir du modèle mécanique fourni, pour générer des données pouvant être similaires à celles d'une expérience. Après cela, la distribution des masses a pu être étudiée. Les méthodes d'analyse classiques ne donnant pas de résultats suffisamment précis, une nouvelle méthode a été mise au point. Elle consiste à représenter la masse par une variable aléatoire construite à partir d'une base de polynômes chaos. Cette méthode donne de bons résultats mais ne permet pas de prendre en compte le lien entre les éclats d'une même charge. Il a donc été décidé ensuite de modéliser la masse par un processus stochastique, et non par une variable aléatoire. La portée des éclats, qui dépend en partie de la masse, a elle aussi été modélisée par un processus. Pour finir, une analyse de sensibilité a été effectuée sur cette portée avec les indices de Sobol. Ces derniers s'appliquant aux variables aléatoires, nous les avons adaptés aux processus stochastiques de manière à prendre en compte les liens entre les éclats. Dans la suite, les résultats de cette dernière analyse pourront être améliorés. Notamment, grâce à des indices présentés en dernière partie qui seraient adaptés aux variables dépendantes, et permettraient l'utilisation de processus stochastiques à accroissements non indépendants. / During this thesis, a method of statistical analysis on sheaf of bomb fragments, in particular on their masses, has been developed. Three samples of incomplete experimental data and a mechanical model which simulate the explosion of a ring were availables. First, a statistical model based on the mechanical model has been designed, to generate data similar to those of an experience. Then, the distribution of the masses has been studied. The classical methods of analysis being not accurate enough, a new method has been developed. It consists in representing the mass by a random variable built from a basis of chaos polynomials. This method gives good results however it doesn't allow to take into account the link between slivers. Therefore, we decided to model the masses by a stochastic process, and not a random variable. The range of fragments, which depends of the masses, has also been modeled by a process. Last, a sensibility analysis has been carried out on this range with Sobol indices. Since these indices are applied to random variables, it was necessary to adapt them to stochastic process in a way that take into account the links between the fragments. In the last part, it is shown how the results of this analysis could be improved. Specifically, the indices presented in the last part are adapted to dependent variables and therefore, they could be suitable to processes with non independent increases.
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Structuration spatiale de la biodiversité agricole dans la zone cotonnière du Mali / Spatial Structure Of Agricultural Biodiversity In Southern Mali

Dembele, Sidi 21 December 2018 (has links)
La diversité des systèmes de culture et des variétés joue un rôle important dans la capacité des agricultures familiales à résister aux chocs socio-économiques et environnementaux. Pour une meilleure conservation, cette diversité agricole doit d’être caractérisée et suivie dans l’espace et le temps. Tandis qu’ils étaient dominés par des éléments sur le prix, les surfaces et les productions jusqu’à récemment, les systèmes de suivi agricole commencent à intégrer les questions de diversité. Alors que jusqu’à la fin des années 1990 elle était considérée comme un facteur limitant dans l’amélioration de la productivité des systèmes d’exploitations dans le processus de sélection variétale. Or dans une situation d’incertitude pluviométrique, pour réduire le risque de cet aléa, les agriculteurs ont recours à plusieurs espèces et variétés pour survivre et produire au travers de tous les aléas rencontrés. La stratégie paysanne consiste à cultiver à la fois plusieurs variétés présentant diverses caractéristiques agronomiques (précocité, rendement, résistance aux pathologies, aux parasites, à la sécheresse, etc.) et culinaires dans un même champ ou dans des champs différents. Cette stratégie permet aux paysans de cultiver les variétés s’adaptant le mieux aux conditions pédologiques de leurs champs et répondant à la fois à leurs divers besoins.C’est dans ce contexte que se situe la présente thèse qui vise principalement à analyser la structuration spatiale de l’agrobiodiversité dans la zone cotonnière. Pour atteindre cet objectif, plusieurs méthodes et approches ont été utilisées. L’approche adoptée combine l’analyse numérique d’images satellitaires et l’utilisation de données issues d’enquêtes de terrain. L’analyse de ces données s’appuie sur la distribution spatiale de la biodiversité et sa corrélation avec les pratiques et les conditions agro-écologiques, les résultats et les performances agronomiques.Les principaux résultats issus de l’analyse des données de l’étude sont :a) On observe une grande hétérogénéité et une diversité des paysages dans la zone cotonnière du Mali-Sud avec au total, onze (11) unités de paysages ;b) On constate une grande diversité au niveau spécifique et des systèmes de culture. Les valeurs moyennes de l’indicateur de diversités spécifiques les plus sont enregistrées dans les villages où la moyenne pluviométrique est comprise entre 700 à 1000 mm d’eau suivis par des villages de moins de 700 mm ;c) L’indicateur de pression spécifique montrant une répartition géographique des pressions des différentes espèces culturales. En effet dans les villages où le coton est en tête de rotation, il exerce une forte pression sur les autres espèces. Dans ces villages, la surface en coton est beaucoup plus importante que celle des autres espèces ;d) Le rendement fait constater que la plupart des villages ont des moyens de coton au-dessus de la moyenne nationale en 2015. En analysant son évolution entre 2013 et 2015, on constate une baisse de rendement dans la plupart des villages même si cette baisse est très souvent en dent de scie avec des hausses en 2013 et 2014.e) L’indicateur de stabilité du rendement montrant que les rendements sont stables avec toutes les espèces sauf le maïs.f) Ces résultats ouvrent la voie à une plus grande contribution de la géographie dans l’analyse agronomique. / The diversity of cropping systems and varieties plays an important role in the ability of family farms to withstand socio-economic and environmental shocks. For better conservation, this agricultural diversity needs to be characterized and monitored in space and time. While they were dominated by elements of price, area and production until recently, agricultural monitoring systems are beginning to integrate diversity issues. The diversity of cropping systems and varieties plays an important role in the ability of family farms to resist socio-economic and environmental shocks, whereas until the end of the 1990s it was considered as a limiting factor in improving the productivity of farming systems in varietal selection processes. In a situation of uncertain rainfall, to reduce the risk of this hazard, farmers use several species and varieties to survive and produce through all the hazards encountered. The peasant strategy consists in cultivating several varieties with different agronomic characteristics (early maturity, yield, resistance to diseases, parasites and drought, etc.) and culinary in the same field or in different fields. This strategy allows farmers to cultivate the varieties best suited to the soil conditions of their fields and to meet their diverse needs.It is in this context that this thesis focuses on the spatial structuring of agrobiodiversity in the cotton zone. To achieve this objective, several methods and approaches have been used. The approach adopted combines the digital analysis of satellite imagery and the use of data from field surveys. The analysis of these data is based on the spatial distribution of biodiversity and its correlation with agro-ecological practices and conditions, agronomic performance and performance.The main results from the analysis of the study data are:a) There is a great heterogeneity and diversity of landscapes in the cotton zone of Mali-Sud with a total of eleven (11) landscape units;b) There is great diversity at the specific level and in cropping systems. The mean values of the most specific indicator of diversity are recorded in villages where the mean rainfall is between 700 and 1000 mm of water followed by villages of less than 700 mm;c) The specific pressure indicator shows a geographical distribution of the pressures of the different crop species. Indeed, in villages where cotton is at the head of rotation, it exerts strong pressure on other species. In these villages, the cotton area is much larger than for the other species;d) For yield, most villages have average yields of cotton above the national average in 2015. Analyzing its evolution between 2013 and 2015, there is a decline in yield in most villages if this decline is very often sawtooth with increases in 2013 and 2014.e) The yield stability indicator shows that yields are stable with all species except maize.These results open the way for a greater contribution of geography in agronomic analysis.
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Les relations homme/femme dans le cinéma iranien postrévolutionnaire, stratégies des réalisateurs, analyse sémiologique / Relationships between man and woman in Iranian post-revolutionary cinema, Directors’ strategies. A semiological analysis

Bagheri Griffaton, Asal 09 May 2012 (has links)
Encadré par la théorie et la méthodologie de la sémiologie des indices proposée par Anne-Marie Houdebine, ce travail analyse les relations homme/femme, sous le coup de la censure, dans le cinéma iranien postrévolutionnaire. L’analyse systémique permet de dégager d’abord les strates iconique, scénique, sonore et technique à l’intérieur du corpus des scènes de films. Ensuite, il met en évidence des éléments explicités qui montrent qu’au plan formel existe un certain nombre de récurrences dans toutes les scènes analysées quel que soit le film travaillé. Au plan de l’expression, une grammaire formelle de la relation homme/femme dans le cinéma iranien a été dégagée. Au plan du contenu, des illusions de proximité et de rapprochement, des déclarations d’amour, des propositions sexuelles, de l’érotisme ainsi que des relations amoureuses et sexuelles surgissent à travers différentes configurations syntagmatiques des indices tels que le regard, le geste avorté, la scène de retour, l’enfant, l’objet symbolique, l’extérieur, l’intérieur, la voiture, la cour, le hors champ, la transition et la musique. En construisant son espace comme l’architecture iranienne traditionnelle entre l’externe (espace réservé aux invités et aux étrangers à la famille) et l’interne (espace privé) mais également en s’emparant des figures de styles à l’instar de la poésie iranienne classique, le cinéma iranien parle pudiquement de l’amour et créé ainsi sa propre iranité concernant les relations homme/femme. / Using Anne-Marie Houdebine’s theory and methodology of semiology of indices, this work analyses the relationships between man and woman in the censured post-revolution Iranian cinema. The systemic analysis highlights the iconic, scenic, auditory and technical stratums within the movie scenes. It also shows explicit elements, which reveals the existence of a certain amount of repetitions on a formal scale in any analyzed film. We can see there is a formal grammar respected when it comes to the expression of man and woman relationships in Iranian cinema. Illusions of closeness, love declarations, sexual propositions, erotism, love and sexual relationships are suggested through various phrasal configurations of the indices, such as glances, abortive gestures, turn around scenes, images of the child, symbolic objects, outside and inside, car, courtyard, off screens, direct transitions and music. Iranian cinema chastely explores love, expressing its own Iranianity regarding relationships between man and woman, by constructing space in the way that traditional Iranian architecture does (external space for guests and internal for family and privacy), but also by using stylistic devices, as in classical Iranian poetry.

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