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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

Reduced-data magnetic resonance imaging reconstruction methods: constraints and solutions.

Hamilton, Lei Hou 11 August 2011 (has links)
Imaging speed is very important in magnetic resonance imaging (MRI), especially in dynamic cardiac applications, which involve respiratory motion and heart motion. With the introduction of reduced-data MR imaging methods, increasing acquisition speed has become possible without requiring a higher gradient system. But these reduced-data imaging methods carry a price for higher imaging speed. This may be a signal-to-noise ratio (SNR) penalty, reduced resolution, or a combination of both. Many methods sacrifice edge information in favor of SNR gain, which is not preferable for applications which require accurate detection of myocardial boundaries. The central goal of this thesis is to develop novel reduced-data imaging methods to improve reconstructed image performance. This thesis presents a novel reduced-data imaging method, PINOT (Parallel Imaging and NOquist in Tandem), to accelerate MR imaging. As illustrated by a variety of computer simulated and real cardiac MRI data experiments, PINOT preserves the edge details, with flexibility of improving SNR by regularization. Another contribution is to exploit the data redundancy from parallel imaging, rFOV and partial Fourier methods. A Gerchberg Reduced Iterative System (GRIS), implemented with the Gerchberg-Papoulis (GP) iterative algorithm is introduced. Under the GRIS, which utilizes a temporal band-limitation constraint in the image reconstruction, a variant of Noquist called iterative implementation iNoquist (iterative Noquist) is proposed. Utilizing a different source of prior information, first combining iNoquist and Partial Fourier technique (phase-constrained iNoquist) and further integrating with parallel imaging methods (PINOT-GRIS) are presented to achieve additional acceleration gains.
52

Nonparametric Learning in High Dimensions

Liu, Han 01 December 2010 (has links)
This thesis develops flexible and principled nonparametric learning algorithms to explore, understand, and predict high dimensional and complex datasets. Such data appear frequently in modern scientific domains and lead to numerous important applications. For example, exploring high dimensional functional magnetic resonance imaging data helps us to better understand brain functionalities; inferring large-scale gene regulatory network is crucial for new drug design and development; detecting anomalies in high dimensional transaction databases is vital for corporate and government security. Our main results include a rigorous theoretical framework and efficient nonparametric learning algorithms that exploit hidden structures to overcome the curse of dimensionality when analyzing massive high dimensional datasets. These algorithms have strong theoretical guarantees and provide high dimensional nonparametric recipes for many important learning tasks, ranging from unsupervised exploratory data analysis to supervised predictive modeling. In this thesis, we address three aspects: 1 Understanding the statistical theories of high dimensional nonparametric inference, including risk, estimation, and model selection consistency; 2 Designing new methods for different data-analysis tasks, including regression, classification, density estimation, graphical model learning, multi-task learning, spatial-temporal adaptive learning; 3 Demonstrating the usefulness of these methods in scientific applications, including functional genomics, cognitive neuroscience, and meteorology. In the last part of this thesis, we also present the future vision of high dimensional and large-scale nonparametric inference.
53

Structural And Event Based Multimodal Video Data Modeling

Oztarak, Hakan 01 December 2005 (has links) (PDF)
Investments on multimedia technology enable us to store many more reflections of the real world in digital world as videos. By recording videos about real world entities, we carry a lot of information to the digital world directly. In order to store and efficiently query this information, a video database system (VDBS) is necessary. In this thesis work, we propose a structural, event based and multimodal (SEBM) video data model for VDBSs. SEBM video data model supports three different modalities that are visual, auditory and textual modalities and we propose that we can dissolve these three modalities with a single SEBM video data model. This proposal is supported by the interpretation of the video data by human. Hence we can answer the content based, spatio-temporal and fuzzy queries of the user more easily, since we store the video data as the way that s/he interprets the real world data. We follow divide and conquer technique when answering very complicated queries. We have implemented the SEBM video data model in a Java based system that uses XML for representing the SEBM data model and Berkeley XML DBMS for storing the data based on the SEBM prototype system.
54

Estudo da marcha com suporte parcial de peso corporal em piso fixo em pacientes hemiparéticos

Sousa, Catarina de Oliveira 10 February 2009 (has links)
Made available in DSpace on 2016-06-02T20:19:11Z (GMT). No. of bitstreams: 1 2225.pdf: 957831 bytes, checksum: 53f3c41bf1c0c7c436de7cebbc4b6d76 (MD5) Previous issue date: 2009-02-10 / Universidade Federal de Minas Gerais / Gait recovery is a one of the main goals of a rehabilitation program for hemiparetic individuals after stroke. Among the different approaches of gait training, the use of systems of partial body weight support (BWS) on treadmill has provided improvements in the pattern of movement of these individuals. However, the strategies adopted to walking on treadmill are different from the ones adopted to walking overground, and overground level is the more usual type of area, it is important to analyze the movement of these individuals while they use the SPPC on overground level, and investigate the effects of the gait training with BWS on ground level. Therefore, this dissertation is composed of two studies. The goal of the first study was to analyze the gait of chronic hemiparetics individuals with and without the system of BWS. For such, 13 chronic hemiparetics individuals were evaluated on three conditions: 1) walking freely with or without assistance; 2) walking with the use of harness of BWS system, however without relief of body weight; 3) walking with the use of harness of BWS system, with 30% body weight relief. Walking speed, cadence, stride length and speed, first and second double support, single support, and swing durations, range of motion (ROM) of ankle, knee, and hip joints, and foot, shank, thigh, and trunk segments of nonparetic and paretic limbs were analyzed on the three conditions. It was found that during the gait with 30% of BWS, participants reduced the speed of locomotion and stride length and speed. However, no effect was observed for temporal asymmetry. The ROM of hip, thigh, and trunk decreased on the 30% of BWS condition, and the trunk had become more upright. Although use of BWS system without relief of body weight has not changed the speed of locomotion, this condition has the same changes that the 30% of BWS conditions, however, more discreet. The changes found in the first study may be attributed to little time to adapt to the gait conditions on overground level with BWS and to the relief of body weight in the lower limbs. The second study aimed to analyse the effects of gait training with BWS on overground level in the gait of chronics hemiparetics. Thus, 12 chronics hemiparetics submitted to sessions of 45 minutes, three times a week, for six weeks participated in this study. The individuals were evaluated walking freely at self-selected comfortable speed before and after the training. The variables examined were walking speed, step length, stride length and speed, first and second double support, and single support durations, maximum and minimum angles, and ROM of foot, shank, thigh, and trunk segments of paretic and nonparetic limbs. After the training period, these individuals walked faster, with symmetry steps, and strides longer and faster. The asymmetry between paretic and nonparetic limbs remained for single support duration, and for ROM and, for maximum and minimum angles for all the segments. The minimum angles of foot and shank, maximum angle of thigh, and the ROM of all segments increased. This approach to training may be used as safe, specific, and promising alternative for gait recovery after stroke. Because this approach of BWS training on overground level is recent, further studies are needed to explore different percentages of weight relief and other stages of strokes, for example, in acute individuals hemiparetics. / A recuperação da marcha é um dos principais objetivos dentro de um programa de reabilitação para hemiparéticos decorrentes de acidente vascular encefálico (AVE). Dentre as diversas abordagens de treinamento de marcha, a que utiliza um sistema de suporte parcial de peso corporal (SPPC) associado à esteira tem proporcionado melhoras no padrão da marcha desses indivíduos. No entanto, as estratégias adotadas durante a marcha na esteira são diferentes das do piso fixo, e sendo piso fixo o tipo de superfície mais habitual de marcha, é importante analisar a marcha desses indivíduos enquanto utilizam o SPPC em piso fixo, e investigar os efeitos do treinamento da marcha com SPPC em piso fixo. Assim, esta dissertação é composta por dois estudos. O primeiro estudo teve como objetivo analisar a marcha de indivíduos hemiparéticos crônicos com e sem o uso do sistema de SPPC. Para tanto, 13 indivíduos hemiparéticos crônicos foram avaliados andando em três condições: 1) livremente com ou sem assistência; 2) com o uso do sistema de SPPC, porém sem alívio do peso corporal; e 3) com o uso do sistema de SPPC com 30% de alívio do peso corporal. Velocidade média de locomoção, cadência, comprimento e velocidade da passada, durações dos períodos de apoio duplo inicial e final, apoio simples e balanço, amplitudes de movimento (ADM) das articulações do tornozelo, joelho e quadril e dos segmentos pé, perna, coxa e tronco dos membros parético e não-parético foram analisados nas três condições. Foi verificado que durante a marcha com 30% de SPPC, os participantes reduziram a velocidade média de locomoção e o comprimento e a velocidade das passadas. No entanto, nenhum efeito foi observado na assimetria temporal. As ADMs do quadril, perna, coxa e tronco diminuíram na condição com 30% de SPPC, sendo que o tronco apresentou-se mais ereto. Apesar do uso do sistema de SPPC sem alívio do peso corporal não ter alterado a velocidade média de locomoção, essa condição proporcionou as mesmas alterações que a condição com 30% de SPPC, entretanto, de forma mais discreta. As alterações encontradas no primeiro estudo podem ser atribuídas ao pouco tempo para a adaptação às condições de marcha em piso fixo com SPPC e ao alívio de peso corporal nos membros inferiores. O segundo estudo teve como objetivo analisar os efeitos de um treinamento com SPPC em piso fixo na marcha de pacientes hemiparéticos crônicos. Dessa forma, 12 hemiparéticos crônicos submetidos a sessões de 45 minutos, três vezes por semana, durante seis semanas participaram do estudo. Os indivíduos foram avaliados andando livremente com velocidade auto-selecionada e confortável antes e após o treinamento proposto. As variáveis analisadas foram velocidade média de locomoção, comprimento do passo, comprimento e velocidade da passada, durações dos períodos de apoio duplo inicial e final, e apoio simples, ângulos máximos e mínimos e ADM dos segmentos pé, perna, coxa e tronco dos membros parético e não-parético. Após o período de treinamento, esses indivíduos passaram a andar mais rapidamente, com passos simétricos, e passadas mais longas e mais rápidas. A assimetria entre os membros parético e não-parético permaneceu para a duração do período de apoio simples e para as ADMs e ângulos máximos e mínimos em todos os segmentos. Os ângulos mínimos dos segmentos pé e perna e o ângulo máximo da coxa, bem como as ADMs de todos os segmentos aumentaram. Essa abordagem de treinamento pode ser adotada como uma alternativa segura, específica e promissora para a recuperação da marcha após AVE. Como essa abordagem de SPPC em piso fixo é recente, outros estudos são necessários para explorar diferentes porcentagens de alívio de peso e em outros estágios do AVE, como por exemplo, em indivíduos hemiparéticos agudos.
55

Impacts of Climate Change on US Commercial and Residential Building Energy Demand

January 2016 (has links)
abstract: Energy consumption in buildings, accounting for 41% of 2010 primary energy consumption in the United States (US), is particularly vulnerable to climate change due to the direct relationship between space heating/cooling and temperature. Past studies have assessed the impact of climate change on long-term mean and/or peak energy demands. However, these studies usually neglected spatial variations in the “balance point” temperature, population distribution effects, air-conditioner (AC) saturation, and the extremes at smaller spatiotemporal scales, making the implications of local-scale vulnerability incomplete. Here I develop empirical relationships between building energy consumption and temperature to explore the impact of climate change on long-term mean and extremes of energy demand, and test the sensitivity of these impacts to various factors. I find increases in summertime electricity demand exceeding 50% and decreases in wintertime non-electric energy demand of more than 40% in some states by the end of the century. The occurrence of the most extreme (appearing once-per-56-years) electricity demand increases more than 2600 fold, while the occurrence of the once per year extreme events increases more than 70 fold by the end of this century. If the changes in population and AC saturation are also accounted for, the impact of climate change on building energy demand will be exacerbated. Using the individual building energy simulation approach, I also estimate the impact of climate change to different building types at over 900 US locations. Large increases in building energy consumption are found in the summer, especially during the daytime (e.g., >100% increase for warehouses, 5-6 pm). Large variation of impact is also found within climate zones, suggesting a potential bias when estimating climate-zone scale changes with a small number of representative locations. As a result of climate change, the building energy expenditures increase in some states (as much as $3 billion/year) while in others, costs decline (as much as $1.4 billion/year). Integrated across the contiguous US, these variations result in a net savings of roughly $4.7 billion/year. However, this must be weighed against the cost (exceeding $19 billion) of adding electricity generation capacity in order to maintain the electricity grid’s reliability in summer. / Dissertation/Thesis / Doctoral Dissertation Environmental Social Science 2016
56

Apport de la télédétection spatiale pour l'étude multiscalaire des interactions climat-surface en Afrique de l'Ouest : étude du bassin versant de l'Ouémé supérieur (Bénin) / Contribution of remote sensing to multi-scale for climate-land cover relationship in West Africa : case study of the Upper Oueme Basin (Benin)

Do, Thi Phuong Thao 03 November 2014 (has links)
Cette thèse s'inscrit dans le cadre du programme international AMMA (Analyse Multidisciplinaire de la Mousson Africaine) dont un des objectifs est de mieux connaître les dynamiques régionales des interactions climat-environnement-société. Elle est une contribution à l'étude de la variabilité spatio-temporelle de la végétation, en fonction des différents types d'occupation du sol et sous contrainte des variations saisonnières et interannuelles de la pluviométrie sur la partie supérieure du bassin versant du fleuve Ouémé, au Bénin. Cette espace possède un important réseau de surveillance hydroclimatique au sol, l'observatoire AMMA-Catch, qui fournit de nombreuses données in situ. L'analyse s'appuie aussi sur différentes données issues de la télédétection satellitaire optique (LANDSAT, SPOT-VGT, MODIS, MSG-SEVIRI ou ECOCLIMAP) pour l'étude de l'occupation du sol, de la variabilité photosynthétique de la végétation ou des estimations pluviométriques (RFE – Rainfall Estimate). L'étude porte principalement sur trois questions : 1) les modifications des états de surface récemment observées dans cette zone expérimentale de l'Ouémé supérieur ; 2) la valorisation des différentes données issues de la télédétection satellitaire pour diagnostiquer la variabilité bioclimatique régionale de la végétation ; 3) la compréhension des interactions à l'interface climat/végétation, pour interpréter certaines variations bioclimatiques intra- et interannuelles en fonction des principaux états de surface. Les principaux résultats suggèrent qu'il est possible de discriminer des relations fonctionnelles selon les principaux états de surface forestiers ou très anthropisés. Les analyses diachroniques par classification d'images Landsat (ETM+) montrent que les espaces cultivés enregistrent régionalement une augmentation de 25 % sur la période 2003-2012. Les superficies de jachère diminuent, alors que les savanes arbustives augmentent. Tous les espaces forestiers perdent en superficie sur la décennie observée, en particulier les forêts denses (a priori protégées dans cette région) avec une baisse supérieure à 16 %. La variabilité spatio-temporelle d'un indice de végétation (NDVI) est significativement dépendante des trois principaux modes d'occupation du sol, même si l'artefact dû à la nébulosité complique les analyses et interprétations. Les contrastes entre le domaine de forêt naturelle encore préservée (la forêt classée) et les espaces en mutation agricole (cultures et jachères) sont particulièrement visibles. Sur la décennie 2002-2012, il n'y a pas de tendance des pluies, mais plutôt une succession de phases sèches et humides, qui induisent finalement une stabilité interannuelle du NDVI. Le déphasage moyen entre pluies et activité végétale est en moyenne de quatre décades, mais il semble que la fin de la saison végétative recule ait reculé d'au moins 10 jours sur la période étudiée, traduisant une modification des précipitations de fin d'année. / This thesis is part of the international AMMA program (Analyse Multidisciplinaire de la Mousson Africaine - Multidisciplinary Analysis of African Monsoon) whose objective is to better understand the regional dynamics of climate-environment-society interactions. It is a contribution to the study of the spatio-temporal variability of vegetation, according to different land use types and under the constraints of seasonal and interannual variations in rainfall in the upper basin of Ouémé river, Benin. This area has an extensive network of hydro-climatic ground monitoring, observatory AMMA-Catch, which provides many in-situ data. The analysis also relies on data from different optical remote sensing satellites (LANDSAT, SPOT-VGT, MODIS, MSG-SEVIRI or ECOCLIMAP) for the study of land occupation, variability of photosynthetic vegetation or rainfall estimate (RFE). The study focuses mainly on three questions: 1) the changes in surface conditions recently observed in the experimental area of upper Ouémé; 2) the analysis of various data from satellite remote sensing to diagnose regional bioclimatic variability of vegetation; 3) the understanding of climate/vegetation interface interactions, in order to interpret certain intra-and interannual bioclimatic variations depending on the main surface conditions. The main results suggest that it is possible to discriminate the functional relationships from the main conditions of forest or anthropized surface. The diachronic analysis through the classification of Landsat (ETM +) images show that the cultivated areas recorded regionally an increase of 25% over the period of 2003-2012. The areas of set-aside decrease, while shrublands increase. All forests lost in area over the decade observed, particularly dense forest (presumably protected in this region) with a drop of over 16%. The spatio-temporal variability of a vegetation index (NDVI) significantly depends on three main types of land use, even though the noise due to the cloud cover complicates the analysis and interpretation. The contrasts between the preserved natural forest area (the forest reserve) and the agricultural areas (crops and fallow) are particularly visible. Over the decade 2002-2012, there is no trend of rainfall, but rather a succession of wet and dry phases, which ultimately induce an interannual stability of NDVI. The average phase difference between rainfall and vegetation activity is four decades, but it seems that the end of the vegetation growing season has retreated back to at least 10 days during the study period, reflecting a change in rainfall at the end of the year.
57

Ecologia alimentar e distribuição espaço-temporal das diferentes fases ontogenéticas da espécie Cynoscion acoupa no estuário do Rio Goiana (PE/PB)

FERREIRA, Guilherme Vitor Batista 01 February 2016 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-06-20T18:42:06Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação (G. Ferreira).pdf: 2368229 bytes, checksum: e7d27dd236d3848f67692455d0a94426 (MD5) / Made available in DSpace on 2016-06-20T18:42:06Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação (G. Ferreira).pdf: 2368229 bytes, checksum: e7d27dd236d3848f67692455d0a94426 (MD5) Previous issue date: 2016-02-01 / Capes / Este estudo avalia a influência espaço-temporal nos padrões de distribuição, ecologia alimentar e ingestão de microplástico da espécie Cynoscion acoupa (Pescada Amarela) ao longo da sua ontogenia, no estuário do rio Goiana, localizado no nordeste do Brasil. A área de estudo se trata de um estuário tropical, com altas médias de temperatura anual e pequenas oscilações. O ambiente está submetido a um regime de mesomaré semi-diurna. As principais alterações encontradas no estuário são oriundas do ciclo sazonal, que está diretamente ligado à pluviometria, divida em quatro estações (início da chuva, fim da chuva, início da seca e fim da seeca), com o intuito de se ter uma maior precisão na avaliação dos processos abiológicos e na comunidade aquática. Os espécimes foram coletados em diferentes porções estuarinas (estuário superior, intermediário e inferior) e nos canais de maré. Simultaneamente a coleta dos dados biológicos foram obtidas informações a respeito dos parâmetros físico-químicos. Os padrões de distribuição e alimentação da espécie estudada ocorrem de forma distinta em relação à ontogenia, sazonalidade e áreas do estuário. A fase juvenil de C. acoupa ocupa a porção superior do estuário durante todas as estações do ano, em busca de baixos valores de salinidade, onde encontram condições ideais apara evitar predadores marinhos. As principais presas dos juvenins no estuário superior foram filamentos de microplástico (FO=63%), amphipoda (FO=28%) e mysidacea (FO=22%). Além disso, no início do período chuvoso, o estuário superior apresenta um papel crucial para o ciclo de vida da espécie, por se caracterizar como uma área berçário para C. acoupa (grande densidade 228,4 ind. ha-1 e baixa biomassa 46 g ha-1 de juvenis), pois a sua contribuição de indivíduos juvenis para a população adulta é muito maior que nos outros hábitats. No ambiente de berçário os juvenis se alimentaram principalmente de filamentos de microplástico (FO=48%), camarão (FO=28%), mysidacea (FO=22%) e amphipoda (FO=21%). Nas demais porções estuarinas, também são registrados indivíduos juvenis, sobretudo nos períodos chuvosos (início da chuva 115 ind ha-1 e fim da chuva 7,3 ind. ha-1), porém em menor escala. Os subadultos de C. acoupa utilizam principalmente o estuário superior durante o início da seca (1,7 ind. ha-1), fim da seca (1,6 ind. ha-1) e início da chuva (6,5 ind. ha-1) como área de alimentação. Predando no estuário superior, no início da seca, principalmente peixes não identificados (FO=50%), no fim da seca, filamentos de microplástico (FO=60%), mysidacea (FO=20%) e syllidae (FO=20%) e no início da chuva, filamentos de nylon FO=100% e peixes não identificados (FO=20%). Durante o fim do período chuvoso os indivíduos subadultos migram para o estuário intermediário (2,3 ind. ha-1) para evitar grandes estresses osmorregulatórios e predaram principalmente amphipoda (FO=75%), Cathorops spixii (FO=50%), Anchovia clupeoides (FO=25%) e peixes não identificados (FO=25%). A fase adulta de C. acoupa foi registrada somente nas porções mais externas do estuário inferior, por se tratar de uma espécie de hábitos costeiros quando completamente desenvolvida. Os indivíduos adultos de C. acoupa predaram principalmente filamentos de nylon (FO=100%), C. spixii (FO=18%), Achirus lineatus (FO=15%), Stellifer stellifer (FO=15%) e camarão (FO=15%). C. acoupa apresentou uma variação no padrão de distribuição em relação a sua ontogenia, sazonalidade e diferentes porções estuarinas. Ao longo do seu desenvolvimento ontogenético C. acoupa também apresentou uma alteração na sua guilda trófica, os juvenis e os subadultos foram classificados como oportunistas e os indivíduos adultos como piscívoros. A grande quantidade de fragmentos e microplástico encontrada na espécie estudada, demostra que ela é particularmente vulnerável a esse tipo de contaminante, sobre tudo os espécimes adultos, que registraram os maiores níveis de contaminação, provavelmente em razão do seu nível trófico, como predadores de topo. / This study assess the spatio-temporal distribution patterns, feeding ecology and microplastic ingestion of the Cynoscion acoupa (Acoupa weakfish) during its ontogeny in the Goianna Estuary, located in northeast Brazil. The study area is a tropical estuary, with high mean temperatures and narrow annual temperature variations. The environment is classified as a semi-diurnal mesotidal estuary. The major environmental dynamics are caused by the seasonal regime, which is related to the rainfall, according to the pluviometry, the area was divided in four different seasons (early dry, late dry, early rainy and late rainy). Biological samples were performed in different estuarine reaches (upper, middle and lower estuary) and in tidal creeks. During the fish sampling, environmental parameters were also recorded. The distribution and feeding patters of the studied species occur in a distinctive form according to the ontogeny, seasonality and estuarine area. The juveniles of C. acoupa occupy the upper estuary, during all seasons, seeking low salinity that provide ideal conditions to avoid marine predators. The main juveniles prey in the upper estuary were microplastic threads (FO=63%), amphipoda (FO=28%) and mysidacea (FO=22%). Moreover in the early rainy season, the upper estuary is crucial for the life ciclo of the species, because it is a nursery ground for C. acoupa (high density 228.4 ind. ha-1 and low biomass 46 g ha-1 of juveniles), as a result of the higher contribution of juveniles for to the adult population than in the other habitats. In the nursery ground, the juveniles of C. acoupa fed mainly on plastic threads (FO=48%), penaeid shrimps (FO=28%), mysidacea (FO=22%) and amphipoda (FO=21%). In other estuarine areas juveniles were also recorded, mainly on the rainy seasons (early rainy 115 ind. ha-1 and late rainy 7.3 ind. ha-1), however with lower densities. The subadults of C. acoupa inhabited mostly the upper estuary, during the early dry (1.7 ind. ha-1), late dry (1.6 ind. ha-1) and early rainy seasons (6.5 ind. ha-1) as a feeding ground. In the upper estuary, during the early season they fed mainly on unidentified fish (FO=50%), in the late dry, plastic threads (FO=60%), mysidacea (FO=20%) and syllidae (FO=20%) and in the early rainy, plastic threads (FO=100%) and unidentified fish (FO=20%). During the late rainy season the subadults of C. acoupa migrated to the middle estuary (2.3 ind. ha-1) to avoid osmoregulatory stress, the subadults and fed mainly on amphipoda (FO=75%), Cathorops spixii (FO=50%), Anchovia clupeoides (FO=25%) and non-identified fish (FO=25%). The adults of C. acoupa were recorded only in seaward areas of the lower estuary, as a result of C. acoupa being a coastal/marine species when fully developed. The adults preyed mostly plastic threads (FO=100%), C. spixii (FO=18%), Achirus lineatus (FO=15%), Stellifer stellifer (FO=15%) and penaeid shrimp (FO=15%). During the ontogenetic process, C. acoupa showed a trophic guild shift, the juveniles and subadults were assigned as opportunistic and the adults as psicivores. C. acoupa showed a variation in the distribution pattern in relation to the ontogeny, seasonality and different estuarine reaches. During the ontogenetic development, C. acoupa showed a trophic guild shift, the juveniles and subadults were assigned as opportunistic and the adults as psicivores. The high occurrence of microplastic threads in the species, evince that C. acoupa is particularly vulnerable to this contaminant, especially the adult phase that registered highest contamination levels, probably due its trophic level, as a top predator.
58

A Importância das praias para o desenvolvimento inicial de assembleias de peixes e macrocrustáceos: variação espaço-temporal da ictiofauna em praias adjacentes a um estuário tropical (Resex Acaú-Goina PE/PB, Brasil)

LACERDA, Carlos Henrique Figueiredo January 2014 (has links)
Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-05-22T17:05:47Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Lacerda2014 (versão BC).pdf: 15671958 bytes, checksum: bd96e677f6b27688458828455de7708d (MD5) / Made available in DSpace on 2017-05-22T17:05:47Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Lacerda2014 (versão BC).pdf: 15671958 bytes, checksum: bd96e677f6b27688458828455de7708d (MD5) Previous issue date: 2014 / As zonas costeiras são consideradas áreas de transição entre os domínios continental e marinho, apresentando alta complexidade e dinamismo. Representando aproximadamente 10% das áreas emersas habitáveis, abrigam atualmente cerca de dois terços da população mundial proporcionando inúmeros serviços econômico-sociais a sociedade humana, que em constante expansão sobrecarrega cada vez mais esses ambientes que exercem papéis ecológicos fundamentais na manutenção da biodiversidade (e produtividade) local e de ecossistemas adjacentes (terrestre e marinho). Dentre os diferentes ecossistemas costeiros, os sistemas estuarinos são bastante conhecidos por estarem presentes em praticamente toda a costa brasileira, assim como por apresentarem grande importância ecológica, econômica e social. Na costa nordeste do Brasil muitos ecossistemas estuarinos ainda encontram-se pouco ou até mesmo não estudados, deixando uma lacuna nos estudos ecológicos referentes a esses ecossistemas que além de grande dinamismo também apresentam muitas particularidades, principalmente ao longo dessa região (NE) onde a plataforma continental é mais estreita. Dessa forma, durante o período de doze meses o habitat praia estabelecido na porção externa do estuário do Rio Goiana foi amplamente estudado, tendo como objetivo principal, avaliar o potencial desse ambiente como berçário para as assembleias de peixes. Um total de três desenhos amostrais foram elaborados e executados nas praias adjacentes a foz do Rio Goiana. A partir do esforço amostral, aspectos relacionados à composição e dinâmica da comunidade de fauna, assim como, características morfodinâmicas e ambientais, foram descritos pela primeira vez nesse habitat, que atualmente encontra-se sob a condição de Reserva Extrativista (RESEX Acaú-Goiana). Foi identificado que as praias adjacentes ao estuário ocorrem junto a um extenso terraço de baixa-mar, cortado pelo canal principal do rio ao longo da margem sul do estuário. Por se tratar de um ambiente dominado pela maré, diferentes ciclos ambientais como o ciclo lunar e circadiano, apresentaram grande influencia nos padrões das variáveis ambientais (salinidade, temperatura da agua, oxigênio dissolvido e profundidade), assim como, no uso do habitat pelas diferentes espécies da fauna. A diferença no regime de chuvas ao longo do ciclo sazonal mostrou-se determinante na composição da comunidade biótica das praias, dominadas por espécies estuarinas durante a estação chuvosa, e abrigando um maior número de espécies costeiras durante a estação seca. Esse ciclo sazonal do habitat, estimulado pelas oscilações de variáveis ambientais como salinidade e temperatura, permite que o habitat contemple um maior número de espécies, e aumenta a eficiência do fluxo de energia entre a porção interna do estuário e habitats costeiros adjacentes. A porção externa do estuário do Rio Goiana proporciona um extenso habitat de aguas rasas, ideal para o desenvolvimento inicial de varias espécies de peixes e crustáceos. É nesse habitat, que o berçário de espécies chave para a subsistência de famílias tradicionais como, Mugil spp. e Callinectes danae ocorre. O grande acúmulo de matéria orgânica, típico de terraços de maré, associado às baixas profundidades e transparência, promovem proteção e recursos alimentares para inúmeras espécies em desenvolvimento inicial, se apresentando assim, como uma importante alternativa de berçário para as assembleias de peixes e crustáceos. As praias estudadas podem exercer um importante papel na manutenção da biodiversidade do ecossistema estuarino e adjacente. As informações levantadas no presente estudo são inéditas, podendo servir de auxilio aos órgãos competentes, em seus planos de manejo de ecossistemas costeiros em unidades de conservação. / Coastal areas are considered transition zones between continental and marine environments, with high complexity and dynamism. Representing approximately 10% of the habitable emerged areas, currently home to about two-thirds of the world population providing numerous services (economic and social) to human society, which in constantly expanding, overwhelms these environments which performing key ecological roles in the maintenance of local biodiversity (and productivity ) and in the adjacent ecosystems (terrestrial and marine). Among the different coastal ecosystems, estuarine systems are well known to be present in practically the entire Brazilian coast, as well as presenting ecological, economic and social services. On the northeast coast of Brazil many estuarine ecosystems are still little or even not studied, leaving a gap in ecological estuarine studies, especially over this region (NE), where the continental shelf is narrower providing many particularities to this ecosystems. So, during the twelve-month period, the beach habitat established in the outer portion of the estuary Goiana was widely studied, with the main purpose of evaluating the potential of this environment as a nursery for fish assemblages. A total of three sampling designs were developed and implemented in the sandy beaches adjacent to Goiana River’s mouth. Aspects related to the composition and dynamics of the faunal community, as well as, morphodynamic and environmental features, were described for the first time in this area, a Marine Conservation Unit, of type Extractive Reserve (RESEX Acaú-Goiás). It was identified that the adjacent estuarine beaches occur along an extensive low tide terrace, crossed by the Goiana main channel along the southern shore. As a tide dominated environment, different environmental cycles, such as circadian and lunar cycle, had great influence on the patterns of environmental variables (salinity, water temperature, dissolved oxygen and depth), as well as in habitat use by different fauna species. The differences in rainfall regime along the seasonal cycle, proved decisive in the composition of the biotic community, dominated by estuarine species during the rainy season, and harboring a greater number of coastal species during the dry season. This seasonal cycle of the habitat, allows the sandy beaches to contemplate a larger number of species, and increases the efficiency of energy flow between the inner portion of the estuary and adjacent coastal habitats. The outer portion of Goiana River estuary provides an extensive shallow water habitat, ideal for the initial development of various species of fish and crustaceans. In this habitat, the nursery of key species for the livelihoods of traditional families as Mugil spp. and Callinectes danae occurs. The large accumulation of organic matter (wrack), typical of tidal terraces, associated to lowest depths and water transparency, promote protection and food resources for many species in early development, presenting as an important alternative nursery and feeding site for fish and crustaceans species. Thus, the sandy beach habitat plays an important role in the livelihood of the local community, as well as in maintaining the biodiversity of estuarine-coastal continuum. The information gathered in this study, should be taken into account by environmental agencies in their planning of coastal ecosystems.
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Composição e distribuição espaço-temporal dos Crustacea componentes da megafauna bêntica na plataforma continental de Sergipe

Mendonça, Luana Marina de Castro 25 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Crustacea is mentioned as a dominant group in almost all continental shelf environments around the Brazilian coast and the taxonomic group with more studies. However, the carcinofauna of some Brazilian shelfs are poorly known, such as Sergipe state. The aim of this study is contribute for the knowledge of Crustacea, components of benthic megafauna from continental shelf of Sergipe and understand how populations communities vary spatially and temporally. The crustaceans were collected with otter trawl in two different seasonal periods, 18 stations between 36°32'W 10°36'S e 37°05’W 11°21’S distributed in 6 transects and in 10, 20 and 30 m isobaths, for a total of 72 stations sampled, between the years 1999 and 2000. Environmental parameters from water and sediment were collect in each station. In laboratory, the organisms were identified to species level and analyzed in terms of richness, abundance and biomass, and the community in terms of diversity indices, equitativity, frequency of occurrence and relative importance indices. The Crustacea was represented by 62749 individuals, distributed in 71 taxa, 199.97 kg of biomass and 77.81km² of density. The collected organisms are representatives of 2 orders, 4 infraorders, 25 families, 46 genus and 64 species. Brachyura presented the greatest number of taxa with 39, followed by Caridea with 12, Dendrobranchiata with 9, Anomura with 7, Stomatopoda with 2 and Achelata with 1. The community was abundant and displayed considerable richness; however, diversity and equitability were low, showing the dominance of the species X. kroyeri, N. schmitti, L. schmitti, F. schmitti and C. ornatus. The fauna varied in space and time and the main abiotic parameters that explain these variations were depth, temperature and the bottom type, especially coarser sediments with high levels of sand and gravel. Six species of Crustacea were recorded for the first time from Sergipe continental shelf, 3 Brachyura (Allactaea lithostrota, Coryrhynchus riisei e Ericerodes minusculus), 2 Caridea (Alpheus armillatus, A. cf. packardii e A. intrisecus) e 1 Stomatopoda (Squilla brasiliensis). / Os crustáceos são citados como grupo dominante em quase todos os ambientes de plataforma ao longo do litoral brasileiro, sendo também o grupo com maior volume de trabalhos realizados. No entanto, algumas plataformas brasileiras ainda têm sua carcinofauna precariamente desconhecida, como é o caso de Sergipe. Nesse sentido, esse trabalho visa contribuir para o conhecimento dos Crustacea, componentes da megafauna bêntica, da plataforma continental de Sergipe, bem como entender como as populações que compõe essa comunidade se distribuem espacial e temporalmente ao longo da plataforma. Os crustáceos foram coletados a partir de arrastos duplos com rede de arrasto pesqueiro em quatro campanhas amostrais entre 1999 e 2000, em 18 estações entre 36°32'W 10°36'S e 37°05’W 11°21’S distribuídas em seis transectos, nas isóbatas de 10, 20 e 30 m, totalizando 72 estações amostradas. Também foram coletados os parâmetros ambientais da água e do sedimento para cada estação. Os organismos foram identificados até o nível de espécie, utilizando literatura taxonômica específica, e analisados em termos de riqueza, abundância e biomassa e, a comunidade foi analisada a partir dos índices de diversidade, equitatividade, frequência de ocorrência e índice de importância relativa. A fauna de Crustacea esteve representada por 62749 indivíduos distribuídos em 71 táxons que somaram 199.97 kg de biomassa úmida e uma densidade de 77.81 ind./km². Os organismos coletados são representantes de 2 ordens, 4 infraordens, 25 famílias, 46 gêneros e 64 espécies. Dos grupos principais de Crustacea, Brachyura apresentou maior número de táxons com 39, seguido de Caridea com 12, Dendrobranchiata com 9, Anomura com 7, Stomatopoda com 2 e Achelata com 1. A comunidade estudada foi abundante e com uma riqueza considerável, mas a diversidade e equitatividade da fauna foram baixas, evidenciando a dominância das espécies X. kroyeri, N. schmitti, L. schmitti, F. schmitti e C. ornatus para a fauna de Crustacea da plataforma continental. A fauna variou em função do tempo e do espaço e os principais parâmetros abióticos que explicaram essas variações foram a profundidade, a temperatura e o tipo de fundo, principalmente os sedimentos mais grossos com altos teores de areia e cascalho. Dentre os Crustacea identificados, foram registrados pela primeira vez para a plataforma continental de Sergipe seis espécies, sendo 3 Brachyura (Allactaea lithostrota, Coryrhynchus riisei e Ericerodes minusculus), 2 Caridea (A. cf. packardii e A. intrisecus) e 1 Stomatopoda (Squilla brasiliensis).
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Caractérisation spatio-temporelle d’impulsions laser de haute puissance / Spatiotemporal characterization of ultra-intense laser pulses

Pariente, Gustave 05 January 2017 (has links)
Les lasers de haute puissance permettent d'atteindre des intensités très importantes (jusqu'à 10²²W.cm⁻²). Parvenir à ce niveau d'intensité nécessite de concentrer une quantité modérée d'énergie (de l'ordre du joule) dans un temps très court (de l'ordre de la dizaine de femtosecondes) sur une surface réduite (de l'ordre du μm²). Ces faisceaux sont donc ultra-courts et focalisés à l'aide d'une optique à grande ouverture. Ces caractéristiques signifient que leur diamètre avant focalisation est grand et leur largeur spectrale est importante. Pour cette raison, ces faisceaux sont à même de présenter des distorsions spatio-spectrales (ou couplages spatio-temporels). Après focalisation, ces distorsions ont pour effet une diminution drastique de l'intensité pic. Ceci est d'autant plus vrai que le système laser est puissant et donc que son diamètre et sa largeur spectrale sont grands. En dépit de cet effet néfaste, les couplages spatio-temporels présentent aussi un intérêt lorsqu'ils sont maitrisés. On peut en effet introduire des couplages spatio-temporels de faible amplitude à des fins expérimentales. Dans les années 1990 et 2000, un effort important a été fourni pour permettre la caractérisation et l'optimisation du profil temporel des lasers femtoseconde. Dans le même temps, des solutions d'optique adaptative ont été développées pour contrôler le profil spatial des faisceaux ultra-intenses et obtenir la meilleure tache focale possible. Les systèmes laser de haute-puissance actuels sont maintenant caractérisés et optimisés indépendamment par ces deux types de diagnostics. Par essence, cette approche est aveugle aux couplages spatio-temporels. Seule une caractérisation spatio-temporelle permettrait de mesurer ces distorsions. Il existait déjà des méthodes de caractérisation spatio-temporelle avant le début de cette thèse. Aucun de ces dispositifs n'avait cependant été adapté à la mesure de faisceaux ultra-intenses. Lors de cette thèse, nous avons développé une nouvelle technique de caractérisation spatio-temporelle appelée TERMITES. Cette technique est basée sur un schéma de spectroscopie par transformée de Fourier auto-référencée. TERMITES nous a permis d'effectuer la première caractérisation spatio-temporelle totale d'un laser 100 TW (le laser UHI-100 du CEA Saclay). Les distorsions spatio-temporelles détectées à l'aide de ces mesures ont confirmé la nécessité d'une généralisation de la métrologie spatio-temporelle des lasers de haute puissance. / High power laser make it possible to reach very high intensities (up to 10²²W.cm⁻²). In order to get to this level of intensity, a moderate quantity of energy (on the order of the Joule) is concentrated in a very short time (on the order of tens of femtoseconds) onto a small surface (on the order of 1 μm²). These beams are therefore ultra-short and focused with a high aperture optic. These features mean that their diameter prior to focus is large and their spectral width is big. As a result, these beams are subject to spatio-spectral distorsions (of spatio-temporal couplings). After focus, these distorsions induce a dramatic reduction of the peak intensity. This situation is all the more true when the laser is more intense and its diameter and spectral width are therefore bigger. Despite their detrimental effects, spatio-temporal couplings can be of great interest when controlled. One can indeed introduce weak spatio-temporal couplings for experimental purposes. In the 1990s and 2000s, a big effort was put in order to characterize dans optimize the temporal profile of femtosecond lasers. Meanwhile, adaptative optics solutions were developed to control the spatial profil of ultra intense laser beams and provide the best focal spot achievable. By nature, this approach is blind to spatio-temporal couplings. Measuring these distorsions requires a spatio-temporal characterization. Before the start of this Phd thesis, spatio-temporal characterization methods already existed. Although none of these devices were ever adapted to the measurement of ultra-intense laser beams. During this Phd Thesis, we developped a new spatio-temporal characterization technique which we called TERMITES. This technique is based on a self-referenced Fourier transform spectroscopy scheme. TERMITES made it possible for us to perform the first total spatio-temporal characterization of a 100 TW laser (UHI-100 at CEA Saclay, France). The detection of spatio-temporal distorsions with the help of these measurements confirmed the need for a generalization of spatio-temporal characterization of ultra-high power lasers.

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