451 resultados para PLS DA
Resumo:
La citologa de impresin corneal es una tcnica atraumtica, simple, rpida y carente de efectos secundarios que permite estudiar las capas celulares ms externas de la superficie ocular, posibilitando el diagnstico de enfermedades de la misma y su monitorizacin durante y despus del tratamiento. Los objetivos de la presente Tesis Doctoral han sido normalizar la tcnica de obtencin y procesamiento de muestras obtenidas por citologa de impresin corneal en la especie canina, determinar los parmetros morfolgicos y morfomtricos fisiolgicos de las clulas epiteliales corneales en perros sanos y establecer las alteraciones celulares corneales en el transcurso de la QCS canina. Adems, se ha estudiado la existencia de una correlacin entre las alteraciones del epitelio corneal y la produccin lagrimal valorada mediante la prueba lagrimal de Schirmer I (PLS I). En este estudio se han incluido 60 perros de diferentes razas que han sido divididos en dos poblaciones: el grupo I, formado por pacientes sanos, con unos valores en la prueba lagrimal de Schirmer I (PLS I) iguales o superiores a 15 mm/min y el grupo II, formado por pacientes diagnosticados de QCS con unos valores en la PLS I comprendidos entre 0 y 14 mm/min. Los ojos de los animales del grupo II han sido categorizados a su vez en 3 subgrupos, estableciendo la gravedad de la enfermedad en funcin de los resultados obtenidos en la PLS I como grave, moderada o leve. Para facilitar la recogida y el manejo de las muestras, adecuar la tcnica para su empleo en animales y disminuir al mnimo cualquier tipo de lesin iatrognica sobre la superficie ocular se ha utilizado un dispositivo simple y eficaz, diferente a los que se han venido empleando tradicionalmente en oftalmologa humana y veterinaria. La valoracin morfomtrica de las clulas se ha realizado atendiendo a los criterios de celularidad de la muestra, separacin intercelular, morfologa de las clulas, tincin citoplasmtica, rea celular, rea nuclear, ratio ncleo/citoplasma (ratio N:C) y alteraciones nucleares...
Resumo:
Biodiesel is a renewable fuel derived from vegetable oils or animal fats, which can be a total or partial substitute for diesel. Since 2005, this fuel was introduced in the Brazilian energy matrix through Law 11.097 that determines the percentage of biodiesel added to diesel oil as well as monitoring the insertion of this fuel in market. The National Agency of Petroleum, Natural Gas and Biofuels (ANP) establish the obligation of adding 7% (v/v) of biodiesel to diesel commercialized in the country, making crucial the analytical control of this content. Therefore, in this study were developed and validated methodologies based on the use of Mid Infrared Spectroscopy (MIR) and Multivariate Calibration by Partial Least Squares (PLS) to quantify the methyl and ethyl biodiesels content of cotton and jatropha in binary blends with diesel at concentration range from 1.00 to 30.00% (v/v), since this is the range specified in standard ABNT NBR 15568. The biodiesels were produced from two routes, using ethanol or methanol, and evaluated according to the parameters: oxidative stability, water content, kinematic viscosity and density, presenting results according to ANP Resolution No. 45/2014. The built PLS models were validated on the basis of ASTM E1655-05 for Infrared Spectroscopy and Multivariate Calibration and ABNT NBR 15568, with satisfactory results due to RMSEP (Root Mean Square Error of Prediction) values below 0.08% (<0.1%), correlation coefficients (R) above 0.9997 and the absence of systematic error (bias). Therefore, the methodologies developed can be a promising alternative in the quality control of this fuel.
Resumo:
Depuis 2000, les tudes concernant lefficacit de la prire sur lamlioration de la sant physique et psychologique des gens pour lesquels on prie se sont multiplies. La consultation de trois banques de donnes (PsycINFO, Medline, Current Content) a permis de rpertorier 189 publications de 1979 2007. Outre la mta-analyse de Master, Spielmans et Goodson (2006), nous avons retenu les tudes qui rpondaient aux deux critres suivants: a) la prire pour autrui est utilise pour traiter un problme de sant physique ou psychologique et b) la prsence dun groupe de prire et dun groupe contrle. Lanalyse des rsultats soulve plusieurs questions sur des critres mthodologiques et pistmologiques ainsi que quelques considrations thiques. Nous discutons en outre de lternel antagonisme entre la dmarche scientifique et la dmarche thologique.
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Num mundo cada vez mais globalizado como o de hoje, a internacionalizao das Instituies de Ensino Superior tem assumido uma importncia estratgica e crescente, no s pela necessidade de preparar adequadamente os seus estudantes para esta nova realidade, como igualmente pelo aumento da competio entre as mesmas. A presena de estudantes internacionais , assim, uma mais-valia a todos os nveis para as Instituies, pelo que fundamental no s procurar atrair os melhores, como igualmente garantir que fiquem satisfeitos com as opes tomadas e leais Instituio escolhida. Foi com o objetivo de conhecer os fatores da satisfao e da lealdade dos estudantes internacionais que esta investigao foi desenvolvida. Assim, com base na informao recolhida atravs de um questionrio numa amostra de 190 estudantes internacionais a estudar no Politcnico de Leiria, efetuou-se o estudo quantitativo, transversal e de natureza conclusiva descritiva, com a finalidade de investigar o impacto dos fatores de escolha e das fontes de informao na lealdade dos estudantes internacionais, mediado pela satisfao com a escolha efetuada. Os resultados da estimao de um modelo estrutural atravs do partial least squares (PLS) evidenciaram que os fatores com maior impacto na satisfao pela escolha efetuada foram: a perceo que tm de Portugal, o ambiente e localizao do Politcnico de Leiria e as fontes de informao (em particular as fontes online). As motivaes pessoais e a perceo da Instituio no revelaram capacidade para explicar a satisfao dos estudantes, muito embora os mesmos os reconheam como fatores importantes na deciso de estudar no estrangeiro e no Politcnico de Leiria. Concluiu-se ainda que a imagem corporativa do Politcnico de Leiria influencia a recomendao de terceiros; as caratersticas de Portugal influenciam a perceo que os estudantes tm do ambiente e localizao da Instituio; por sua vez, Portugal e a regio onde se situa o Politcnico de Leiria influenciam a sua imagem corporativa; a satisfao e a imagem corporativa do Politcnico de Leiria explicam a lealdade dos estudantes internacionais, medida em termos da inteno de a recomendar a familiares, amigos e conhecidos e de partilhar informaes sobre a mesma nas redes sociais. Para completar o presente estudo, foi ainda efetuada uma anlise comparativa dos estudantes em funo da sua provenincia, tendo-se observado diferenas significativas entre eles. De notar que os estudantes latino-americanos declaram-se mais satisfeitos e com maior propenso para recomendar o Politcnico de Leiria aos seus conhecidos. Com base nos resultados obtidos apresentado um conjunto de recomendaes ao Politcnico de Leiria, teis para implementar estratgias de marketing e de comunicao mais adequadas captao e fidelizao dos estudantes internacionais e, assim, contribuir para a sua internacionalizao.
Resumo:
No mercado automvel as diferenas de qualidade nos vrios produtos tem vindo a esbater-se ao longo dos ltimos anos, desta forma, o desempenho das marcas resulta cada vez mais do esforo e das estratgias de marketing. Apesar da deciso de compra do automvel ser exigente e requerer um elevado envolvimento dos consumidores, os fatores hednicos assumem um protagonismo crescente, afinal o automvel , para a maioria das pessoas, uma exteno da sua personalidade ou da imagem que pretendem transmitir para a sociedade, no sendo somente um meio de transporte. Cada marca de automveis e cada modelo transmite uma mensagem e um simbolismo que o consumidor deseja ou despreza e que condicionam a sua Inteno de Compra. Assim, interessa conhecer os fatores que influenciam a Inteno de Compra do automvel. Nesse sentido, com base numa amostra de 861 potenciais compradores de automvel realizou-se um estudo quantitativo, de natureza descritiva e conclusiva, com a finalidade de confirmar em que medida as variveis selecionadas: Brand Equity, Brand Experience, Publicidade, Experincia Anterior, Word-of-Mouth Recebido e Imagem do Pas de Origem, determinam, direta ou indiretamente, a inteno de compra da marca de automveis. Os resultados da estimao do modelo estrutural, atravs do PLS, evidenciaram que as experincias sensoriais e comportamentais explicam 22% da avaliao das experincias anteriores com a marca; a experincia anterior com a marca, a imagem do pas de origem e o WOM explicam 52,8% da qualidade percecionada; a experincia anterior com a marca, a publicidade e o WOM recebido contribui para determinar 18,8% das associaes marca; a lealdade marca, a qualidade percecionada e as associaes marca explicam 57,4% do brand equity; por fim, a lealdade marca, a experincia anterior e o brand equity explicam 47,6% da inteno de compra de uma determinada marca de automveis. Acresce ainda que o grupo de marcas de maior prestgio se destacam por uma maior promoo do marketing relacional e experiencial. Deste estudo, conclui-se que prticas do marketing relacional e experiencial devem ser usadas para estreitar o relacionamento com clientes e potenciais clientes e para promover o valor da marca. As experincias de marketing devem ser objeto de uma boa estratgia de comunicao integrada, suportada nas novas tecnologias.
Resumo:
Depuis 2000, les tudes concernant lefficacit de la prire sur lamlioration de la sant physique et psychologique des gens pour lesquels on prie se sont multiplies. La consultation de trois banques de donnes (PsycINFO, Medline, Current Content) a permis de rpertorier 189 publications de 1979 2007. Outre la mta-analyse de Master, Spielmans et Goodson (2006), nous avons retenu les tudes qui rpondaient aux deux critres suivants: a) la prire pour autrui est utilise pour traiter un problme de sant physique ou psychologique et b) la prsence dun groupe de prire et dun groupe contrle. Lanalyse des rsultats soulve plusieurs questions sur des critres mthodologiques et pistmologiques ainsi que quelques considrations thiques. Nous discutons en outre de lternel antagonisme entre la dmarche scientifique et la dmarche thologique.
Resumo:
Quantitative Structure-Activity Relationship (QSAR) has been applied extensively in predicting toxicity of Disinfection By-Products (DBPs) in drinking water. Among many toxicological properties, acute and chronic toxicities of DBPs have been widely used in health risk assessment of DBPs. These toxicities are correlated with molecular properties, which are usually correlated with molecular descriptors. The primary goals of this thesis are: 1) to investigate the effects of molecular descriptors (e.g., chlorine number) on molecular properties such as energy of the lowest unoccupied molecular orbital (ELUMO) via QSAR modelling and analysis; 2) to validate the models by using internal and external cross-validation techniques; 3) to quantify the model uncertainties through Taylor and Monte Carlo Simulation. One of the very important ways to predict molecular properties such as ELUMO is using QSAR analysis. In this study, number of chlorine (NCl) and number of carbon (NC) as well as energy of the highest occupied molecular orbital (EHOMO) are used as molecular descriptors. There are typically three approaches used in QSAR model development: 1) Linear or Multi-linear Regression (MLR); 2) Partial Least Squares (PLS); and 3) Principle Component Regression (PCR). In QSAR analysis, a very critical step is model validation after QSAR models are established and before applying them to toxicity prediction. The DBPs to be studied include five chemical classes: chlorinated alkanes, alkenes, and aromatics. In addition, validated QSARs are developed to describe the toxicity of selected groups (i.e., chloro-alkane and aromatic compounds with a nitro- or cyano group) of DBP chemicals to three types of organisms (e.g., Fish, T. pyriformis, and P.pyosphoreum) based on experimental toxicity data from the literature. The results show that: 1) QSAR models to predict molecular property built by MLR, PLS or PCR can be used either to select valid data points or to eliminate outliers; 2) The Leave-One-Out Cross-Validation procedure by itself is not enough to give a reliable representation of the predictive ability of the QSAR models, however, Leave-Many-Out/K-fold cross-validation and external validation can be applied together to achieve more reliable results; 3) ELUMO are shown to correlate highly with the NCl for several classes of DBPs; and 4) According to uncertainty analysis using Taylor method, the uncertainty of QSAR models is contributed mostly from NCl for all DBP classes.
Resumo:
A number of studies have shown that Fourier transform infrared spectroscopy (FTIR) can be applied to quantitatively assess lacustrine sediment constituents. In this study, we developed calibration models based on FTIR for the quantitative determination of biogenic silica (BSi; n = 420; gradient: 0.9-56.5%), total organic carbon (TOC; n = 309; gradient: 0-2.9%), and total inorganic carbon (TIC; n= 152; gradient: 0-0.4%) in a 318 m-long sediment record with a basal age of 3.6 million years from Lake El'gygytgyn, Far East Russian Arctic. The developed partial least squares (PLS) regression models yield high cross-validated (CV) R2CV = 0.86-0.91 and low root mean square error of cross-validation (RMSECV) (3.1-7.0% of the gradient for the different properties). By applying these models to 6771 samples from the entire sediment record, we obtained detailed insight into bioproductivity variations in Lake El'gygytgyn throughout the middle to late Pliocene and Quaternary. High accumulation rates of BSi indicate a productivity maximum during the middle Pliocene (3.6-3.3 Ma), followed by gradually decreasing rates during the late Pliocene and Quaternary. The average BSi accumulation during the middle Pliocene was ~3 times higher than maximum accumulation rates during the past 1.5 million years. The indicated progressive deterioration of environmental and climatic conditions in the Siberian Arctic starting at ca. 3.3 Ma is consistent with the first occurrence of glacial periods and the finally complete establishment of glacial-interglacial cycles during the Quaternary.
Resumo:
This work outlines the theoretical advantages of multivariate methods in biomechanical data, validates the proposed methods and outlines new clinical findings relating to knee osteoarthritis that were made possible by this approach. New techniques were based on existing multivariate approaches, Partial Least Squares (PLS) and Non-negative Matrix Factorization (NMF) and validated using existing data sets. The new techniques developed, PCA-PLS-LDA (Principal Component Analysis Partial Least Squares Linear Discriminant Analysis), PCA-PLS-MLR (Principal Component Analysis Partial Least Squares Multiple Linear Regression) and Waveform Similarity (based on NMF) were developed to address the challenging characteristics of biomechanical data, variability and correlation. As a result, these new structure-seeking technique revealed new clinical findings. The first new clinical finding relates to the relationship between pain, radiographic severity and mechanics. Simultaneous analysis of pain and radiographic severity outcomes, a first in biomechanics, revealed that the knee adduction moments relationship to radiographic features is mediated by pain in subjects with moderate osteoarthritis. The second clinical finding was quantifying the importance of neuromuscular patterns in brace effectiveness for patients with knee osteoarthritis. I found that brace effectiveness was more related to the patients unbraced neuromuscular patterns than it was to mechanics, and that these neuromuscular patterns were more complicated than simply increased overall muscle activity, as previously thought.
Resumo:
Fossil associations from the middle and upper Eocene (Bartonian and Priabonian) sedimentary succession of the Pamplona Basin are described. This succession was accumulated in the western part of the South Pyrenean peripheral foreland basin and extends from deep-marine turbiditic (Ezkaba Sandstone Formation) to deltaic (Pamplona Marl, Ardanatz Sandstone and Ilundain Marl formations) and marginal marine deposits (Gendulain Formation). The micropalaeontological content is high. It is dominated by foraminifera, and common ostracods and other microfossils are also present. The fossil ichnoasssemblages include at least 23 ichnogenera and 28 ichnospecies indicative of Nereites, Cruziana, Glossifungites and ?Scoyenia-Mermia ichnofacies. Body macrofossils of 78 taxa corresponding to macroforaminifera, sponges, corals, bryozoans, brachiopods, annelids, molluscs, arthropods, echinoderms and vertebrates have been identified. Both the number of ichnotaxa and of species (e. g. bryozoans, molluscs and condrichthyans) may be considerably higher. Body fossil assemblages are comparable to those from the Eocene of the Nord Pyrenean area (Basque Coast), and also to those from the Eocene of the west-central and eastern part of South Pyrenean area (Aragon and Catalonia). At the European scale, the molluscs assemblages seem endemic from the Pyrenean area, although several Tethyan (Italy and Alps) and Northern elements (Paris basin and Normandy) have been recorded. Palaeontological data of studied sedimentary units fit well with the shallowing process that throughout the middle and late Eocene occurs in the area, according to the sedimentological and stratigraphical data.
Resumo:
This paper is part of a special issue of Applied Geochemistry focusing on reliable applications of compositional multivariate statistical methods. This study outlines the application of compositional data analysis (CoDa) to calibration of geochemical data and multivariate statistical modelling of geochemistry and grain-size data from a set of Holocene sedimentary cores from the Ganges-Brahmaputra (G-B) delta. Over the last two decades, understanding near-continuous records of sedimentary sequences has required the use of core-scanning X-ray fluorescence (XRF) spectrometry, for both terrestrial and marine sedimentary sequences. Initial XRF data are generally unusable in raw-format, requiring data processing in order to remove instrument bias, as well as informed sequence interpretation. The applicability of these conventional calibration equations to core-scanning XRF data are further limited by the constraints posed by unknown measurement geometry and specimen homogeneity, as well as matrix effects. Log-ratio based calibration schemes have been developed and applied to clastic sedimentary sequences focusing mainly on energy dispersive-XRF (ED-XRF) core-scanning. This study has applied high resolution core-scanning XRF to Holocene sedimentary sequences from the tidal-dominated Indian Sundarbans, (Ganges-Brahmaputra delta plain). The Log-Ratio Calibration Equation (LRCE) was applied to a sub-set of core-scan and conventional ED-XRF data to quantify elemental composition. This provides a robust calibration scheme using reduced major axis regression of log-ratio transformed geochemical data. Through partial least squares (PLS) modelling of geochemical and grain-size data, it is possible to derive robust proxy information for the Sundarbans depositional environment. The application of these techniques to Holocene sedimentary data offers an improved methodological framework for unravelling Holocene sedimentation patterns.
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Tese apresentada ao Programa de Doutorado em Administrao da Universidade Municipal de So Caetano do Sul para a obteno do ttulo de Doutor em Administrao
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O presente trabalho teve como objetivo a identificao de atributos relacionados atratividade de clientes em clusters comerciais, na percepo de consumidores. Partindo-se da atratividade de clientes para lojas, desenvolveu-se um construto de avaliao de atratividade de clientes para clusters comerciais. Por meio de estudo descritivo-quantitativo junto a 240 consumidores, em dois reconhecidos clusters comerciais, utilizando-se a tcnica de PLS-PM (Partial Least Squares Path Modeling), avaliou-se a relao entre a atratividade de clientes (varivel reflexiva) e as dimenses do mix varejista de clusters comerciais (variveis latentes), a partir do tratamento de indicadores de efeitos observveis. Como principais resultados, observou-se que: (1) atratividade est associada significativamente s variveis latentes, sugerindo robustez do modelo; (2) condies de compra e preos so dimenses com maior associao atratividade de clientes, embora lojas, produtos e atendimento apresentem relevncia; e (3) localizao apresentou-se como dimenso menos correlacionada atratividade de clientes para ambos os clusters.
Resumo:
<p>[ES] On 31 August 2003, at 11:40 local time, c. 5 nm southwest of São Nicolau 16º33.1N, 024º27.7W), Cape Verde Islands, GT and PLS observed c.20 Fraser’s Dolphins Lagenodelphis hosei Fraser, 1956 (Fig.1). The sighting was made under excellent weather conditions (sea state Beaufort 2 with sun) from the 39.6 m diesel engine powered oceanographic research vessel Taliarte during a two week cetacean survey conducted as part of the Hydrocarpo project. The animals were c. 2.5 m in length, with a short beak, robust ody, small dorsal and pectoral fins and showed the characteristic longitudinal striping (cf. efferson et al.1993, Carwardine 1995).</p>
Resumo:
Denna uppsats diskuterar hur invnare i Malung anvnder historia kollektivt i det offentliga. Det visar sig att invnarna i mngt och mycket anvnder historia fr att markera en Guldlder dr orten Malung i Sverige en gng var ett blomstrande industrisamhlle, idag ett minne blott. Anvndning av historia i Malung visar sig vara en nskan att tervnda till den tid d orten var ledande i landet inom skinn-, pls- och kvarnstensindustrin. Men det r inte inom skinn, pls och kvarnstenstillverkning som terskapandet av det frflutna syns, utan i andra mer generella historiska och vardagsnra omrdena ssom vvning, malning och bakning, dr en mer allmn historia efterstrvas. Skinn-, pls- och kvarnstensindustrin terfinns sledes inte som grund fr en identitet nr det gller historiebruk i Malung.
