975 resultados para multivariate methods


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The airliner cabin environment and its effects on occupant health have not been fully characterized. This dissertation is: (1) A review of airliner environmental control systems (ECSs) that modulate the ventilation, temperature, relative humidity (RH), and barometric pressure (PB) of the cabin environment---variables related to occupant comfort and health. (2) A review and assessment of the methods and findings of key cabin air quality (CAQ) investigations. Several significant deficiencies impede the drawing of inferences about CAQ, e.g., lack of detail about investigative methods, differences in methods between investigations, limited assessment of CAQ variables, small sample sizes, and technological deficiencies of data collection. (3) A comprehensive evaluation of the methods used in the subsequent NIOSH-FAA Airliner CAQ Exposure Assessment Feasibility Study (STUDY) in which this author participated. A number of problems were identified which limit the usefulness of the data. (4) An analysis of the reliable 10-flight STUDY data. Univariate and multivariate methods applied to CO2 (a surrogate for air contaminants), temperature, RH, and PB, in association with percent passenger load, ventilation system, flight duration, airliner body type, and measurement location within the cabin, revealed neither the measured values nor their variability exceeded established health-based exposure limits. Regression analyses suggest CO2, temperature, and RH were affected by percent passenger load. In-flight measurements of CO2 and RH were relatively independent of ventilation system type or flight duration. Cabin temperature was associated with percent passenger load, ventilation system type, and flight duration. (5) A synthesis of the implications of the airliner ECS and cabin O2 environment on occupant health. A model was developed to predict consequences of the airliner cabin pressure altitude 8,000 ft limit and resulting model-estimated PO2 on cardiopulmonary status. Based on the PB, altitude, and environmental data derived from the 10 STUDY flights, the predicted PaO2 of adults with COPD, or elderly adults with or without COPD, breathing ambient cabin air could be < 55 mm Hg (SaO2 < 88%). Reduction in cabin PB found in the STUDY flights could aggravate various medical conditions and require the use of in-flight supplemental O2. ^

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Nuevas biotecnologías permiten obtener información para caracterizar materiales genéticos a partir de múltiples marcadores, ya sean éstos moleculares y/o morfológicos. La ordenación del material genético a través de la exploración de patrones de variabilidad multidimensionales se aborda mediante diversas técnicas de análisis multivariado. Las técnicas multivariadas de reducción de dimensión (TRD) y la representación gráfica de las mismas cobran sustancial importancia en la visualización de datos multivariados en espacios de baja dimensión ya que facilitan la interpretación de interrelaciones entre las variables (marcadores) y entre los casos u observaciones bajo análisis. Tanto el Análisis de Componentes Principales, como el Análisis de Coordenadas Principales y el Análisis de Procrustes Generalizado son TRD aplicables a datos provenientes de marcadores moleculares y/o morfológicos. Los Árboles de Mínimo Recorrido y los biplots constituyen técnicas para lograr representaciones geométricas de resultados provenientes de TRD. En este trabajo se describen estas técnicas multivariadas y se ilustran sus aplicaciones sobre dos conjuntos de datos, moleculares y morfológicos, usados para caracterizar material genético fúngico.

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Automatic segmentation using univariate and multivariate techniques provides more objective and efficient segmentations of the river systems (Alber & Piégay, 2011) and can be complementary to the expert criteria traditionally used (Brenden et al., 2008) INTEREST: A powerful tool to objectively segment the continuity of rivers, which is required for diagnosing problems associated to human impacts OBJECTIVE: To evaluate the potentiality of univariate and multivariate methods in the assessment of river adjustments produced by flow regulation

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Two objects with homologous landmarks are said to be of the same shape if the configurations of landmarks of one object can be exactly matched with that of the other by translation, rotation/reflection, and scaling. The observations on an object are coordinates of its landmarks with reference to a set of orthogonal coordinate axes in an appropriate dimensional space. The origin, choice of units, and orientation of the coordinate axes with respect to an object may be different from object to object. In such a case, how do we quantify the shape of an object, find the mean and variation of shape in a population of objects, compare the mean shapes in two or more different populations, and discriminate between objects belonging to two or more different shape distributions. We develop some methods that are invariant to translation, rotation, and scaling of the observations on each object and thereby provide generalizations of multivariate methods for shape analysis.

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A cetamina é uma droga amplamente utilizada e o seu uso inadequado tem sido associado à graves consequências para a saúde humana. Embora as propriedades farmacológicas deste agente em doses terapêuticas sejam bem conhecidas, existem poucos estudos sobre os efeitos secundários induzidos por doses não-terapêuticas, incluindo os efeitos nos estados de ansiedade e agressividade. Neste contexto, os modelos animais são uma etapa importante na investigação e elucidação do mecanismo de ação a nível comportamental. O zebrafish (Danio rerio) é um novo organismo-modelo, interessante e promissor, uma vez que apresenta alta similaridade fisiológica, genética e neuroquímica com seres humanos, respostas comportamentais bem definidas e rápida absorção de compostos de interesse em meio aquoso além de apresentar uma série de vantagens em relação aos modelos mamíferos tais como manutenção de baixo custo, prática e executável em espaços reduzidos. Nesse sentido, faz-se necessário a execução de ensaios comportamentais em conjunto com análises estatísticas robustas e rápidas tais como ANOVA e Métodos Multivariados; e também o desenvolvimento de métodos analíticos sensíveis, precisos e rápidos para determinação de compostos de interesse em matrizes biológicas provenientes do animal. Os objetivos do presente trabalho foram a investigação dos efeitos da cetamina sobre a ansiedade e a agressividade em zebrafish adulto empregando Testes de Claro-Escuro e Testes do Espelho e métodos estatísticos univariados (ANOVA) e multivariados (PCA, HCA e SIMCA) assim como o desenvolvimento de método analítico para determinação da cetamina em matriz biológica proveniente do animal, empregando Extração Líquido-Líquido e Cromatografia em Fase Gasosa acoplada ao Detector de Nitrogênio-Fósforo (GC-NPD). Os resultados comportamentais indicaram que a cetamina produziu um efeito significativo dose-dependente em zebrafish adulto na latência à área clara, no número de cruzamentos entre as áreas e no tempo de exploração da área clara. Os resultados das análises SIMCA e PCA mostraram uma maior similaridade entre o grupo controle e os grupos de tratamento expostos às doses mais baixas (5 e 20 mg L-1) e entre os grupos expostos às doses de 40 e 60 mg L-1. Na análise por PCA, dois componentes principais responderam por 88,74% de toda a informação do sistema, sendo que 62,59% da informação cumulativa do sistema foi descrito pela primeira componente principal. As classificações HCA e SIMCA seguiram uma evolução lógica na distribuição das amostras por classes. As doses mais altas de cetamina induziram uma distribuição mais homogênea das amostras enquanto as doses mais baixas e o controle resultaram em distribuições mais dispersas. No Teste do Espelho, a cetamina não induziu efeitos significativos no comportamento dos animais. Estes resultados sugerem que a cetamina é modulador de comportamentos ansiosos, sem efeitos indutores de agressividade. Os resultados da validação do método cromatográfico indicaram uma extração com valores de recuperação entre 33,65% e 70,89%. A curva de calibração foi linear com valor de R2 superior a 0,99. O limite de detecção (LOD) foi de 1 ng e o limite de quantificação (LOQ) foi de 5 ng. A exatidão do método cromatográfico manteve-se entre - 24,83% e - 1,258%, a precisão intra-ensaio entre 2,67 e 14,5% e a precisão inter-ensaio entre 1,93 e 13,9%.

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Thesis (Master's)--University of Washington, 2016-06

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2000 Mathematics Subject Classification: 62H30, 62P99

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A rich material of Heteroptera extracted with Berlese funnels by Dr. I. Loksa between 1953–1974 in Hungary, has been examined. Altogether 157 true bug species have been identified. The ground-living heteropteran assemblages collected in different plant communities, substrata, phytogeographical provinces and seasons have been compared with multivariate methods. Because of the unequal number of samples, the objects have been standardized with stochastic simulation. There are several true bug species, which have been collected in almost all of the plant communities. However, characteristic ground-living heteropteran assemblages have been found in numerous Hungarian plant community types. Leaf litter and debris seem to have characteristic bug assemblages. Some differences have also been recognised between the bug fauna of mosses growing on different surfaces. Most of the species have been found in all of the great phytogeographical provinces of Hungary. Most high-dominance species, which have been collected, can be found at the ground-level almost throughout the year. Specimens of many other species have been collected with Berlese funnels in spring, autumn and/or winter. The diversities of the ground-living heteropteran assemblages of the examined objects have also been compared.

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As a third part of a series of papers on the ground-living true bugs of Hungary, the species belonging to the lace bug genus Acalypta Westwood, 1840 (Insecta: Heteroptera: Tingidae) were studied. Extensive materials collected with Berlese funnels during about 20 years all over Hungary were identified. Based on these sporadic data of many years, faunistic notes are given on some Hungarian species. The seasonal occurrence of the species are discussed. The numbers of specimens of different Acalypta species collected in diverse plant communities are compared with multivariate methods. Materials collected with pitfall traps between 1979–1982 at Bugac, Kiskunság National Park were also processed. In this area, only A. marginata and A. gracilis occurred, both in great number. The temporal changes of the populations are discussed. Significant differences could be observed between the microhabitat distribution of the two species: both species occurred in very low number in traps placed out in patches colonized by dune-slack purple moorgrass meadow; Acalypta gracilis preferred distinctly the Pannonic dune open grassland patches; A. marginata occurred in almost equal number in Pannonic dune open grassland and in Pannonic sand puszta patches.

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The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS. Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets. An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for μXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for μXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for μXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes. Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets. Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.

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The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS. Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets. An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for µXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for µXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for µXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes. Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets. Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.

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Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação