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| Registros recuperados: 72 | |
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| Zamora Tirado, Paula Erika. |
| El presente el trabajo se desarrolló en la provincia fisiográfica Eje Volcánico Mexicano donde los procesos de erosión por cárcavas son frecuentes y relevantes, ocasionado importantes pérdidas económicas y ambientales, con el objetivo de caracterizar los parámetros ambientales que influyen en la formación de cárcavas, como: material parental, suelo, fase física, erosionabilidad, pendiente, longitud de pendiente, orientación, curvatura horizontal y vertical, índice de posición topográfica, índice topográfico de humedad, índice de Fournier, índice de vegetación ajustada al suelo y distancia a estructuras volcánicas. Se realizó un Análisis de Componentes Principales (ACP) con el propósito de identificar las variables que mejor expliquen la formación de... |
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Palavras-chave: Análisis de componentes principales; Análisis de máxima verosimilitud; Erosión en cárcavas; Modelación en cárcavas; Variables ambientales; Principal component analysis; Maximum likelihood analysis; Gully; Ravine modeling; Environmental variables; Edafología; Maestría. |
| Ano: 2014 |
URL: http://hdl.handle.net/10521/2372 |
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| Castro-Silva,Carolina; Ruíz-Valdiviezo,Víctor M; Valenzuela-Encinas,César; Alcántara-Hernández,Rocio J; Navarro-Noya,Yendi E; Vázquez-Núñez,Edgar; Luna-Guido,Marco; Marsch,Rodolfo; Dendooven,Luc. |
| Background: The application of polycyclic aromatic hydrocarbons (PAHs) will affect the bacterial community structure as some groups will be favoured and others not. An alkaline saline soil with electrolytic conductivity (EC) 56 dS m-1 was spiked with anthracene and acetone while their effect on bacterial community structure was investigated. Results: The percentages of Acidobacteria and Actinobacteria decreased over time, while the percentage of Proteobacteria, mostly Xanthomonadales, increased. The percentage of the phylotypes belonging to the Nocardioides, Rhodococcus and Streptomyces, known degraders of PAHs, was larger in the anthracene-amended soil than in the acetone-amended and unamended soil at day 14. The phylotypes belonging to the genera... |
| Tipo: Journal article |
Palavras-chave: C dynamics; N mineralization; Phylogenetic analysis; Polycyclic aromatic hydrocarbons; Principal component analysis; UniFrac. |
| Ano: 2013 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000500010 |
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| Rodrigues,Tatiana P. N. da S.; Pandorfi,Héliton; Guiselini,Cristiane; Almeida,Gledson L. P. de; Morrill,Waldirene B. B.. |
| ABSTRACT The objective of this research was to analyze the differences between the food behaviors observed under the factors of production environment, sex and lighting system, using stochastic tools of multivariate analysis. As for the thermal characteristics of the environment, air temperature (T, °C), enthalpy (H, kJ kg-1), and black globe temperature and humidity index (BGTHI) showed high positive correlation with each other and strong negative correlation with relative humidity (RH, %). The “male drinking” behavior was positively associated with thermal characteristics of the environment in the three periods of the day, that is, the act of drinking more water would be a way to alleviate thermal stress. Birds subjected to red LED showed a strong... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Animal welfare; Broiler farming; Lighting system; Principal component analysis; Thermal comfort. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000300272 |
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| Elesbon,Abrahão A. A.; Silva,Demetrius D. da; Sediyama,Gilberto C.; Guedes,Hugo A. S; Ribeiro,Carlos A. A. S.; Ribeiro,Celso B. de M.. |
| ABSTRACT This study aimed to develop a methodology based on multivariate statistical analysis of principal components and cluster analysis, in order to identify the most representative variables in studies of minimum streamflow regionalization, and to optimize the identification of the hydrologically homogeneous regions for the Doce river basin. Ten variables were used, referring to the river basin climatic and morphometric characteristics. These variables were individualized for each of the 61 gauging stations. Three dependent variables that are indicative of minimum streamflow (Q7,10, Q90 and Q95). And seven independent variables that concern to climatic and morphometric characteristics of the basin (total annual rainfall – Pa; total semiannual rainfall... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Principal component analysis; Cluster analysis; Homogeneous regions. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162015000500838 |
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| Grasso,Andrés N; Goldberg,Virginia; Navajas,Elly A; Iriarte,Wanda; Gimeno,Diego; Aguilar,Ignacio; Medrano,Juan F; Rincón,Gonzalo; Ciappesoni,Gabriel. |
| The aim of this study was to investigate the genetic diversity within and among three breeds of sheep: Corriedale, Merino and Creole. Sheep from the three breeds (Merino n = 110, Corriedale n = 108 and Creole n = 10) were genotyped using the Illumina Ovine SNP50 beadchip®. Genetic diversity was evaluated by comparing the minor allele frequency (MAF) among breeds. Population structure and genetic differentiation were assessed using STRUCTURE software, principal component analysis (PCA) and fixation index (F ST). Fixed markers (MAF = 0) that were different among breeds were identified as specific breed markers. Using a subset of 18,181 single nucleotide polymorphisms (SNPs), PCA and STUCTURE analysis were able to explain population stratification within... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allele frequencies breed composition; Fixation index; Ovine SNP50; Population stratification; Principal component analysis. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572014000300011 |
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| HIGA, R. H.; GIACHETTO, P. F.; YAMAGISHI, M. E. B.; IBELLI, A. M. G.; REGITANO, L. C. de A.; CARDOSO, F. F.. |
| O objetivo deste trabalho é apresentar a análise de agrupamento de dados de expressão gênica, conforme realizada no escopo da ?Rede Genômica Animal?. Na seção 2, são apresentados conceitos básicos sobre análises de agrupamento. Em particular, os algoritmos de agrupamento utilizados nessas análises compreendem aqueles mais conhecidos, como k-means, SOM e agrupamento hierárquico. A plataforma de análise escolhida para realização das análises de agrupamento na ?Rede Genômica Animal? é o ambiente de análise estatística R (R DEVELOPMENT CORE TEAM, 2010) e o projeto Bioconductor (GENTLEMAN et al., 2004). Assim, na seção 3 é apresentado um exemplo completo de análise de agrupamento e seu respectivo script R. |
| Tipo: Comunicado Técnico (INFOTECA-E) |
Palavras-chave: Agrupamento de dados; Expressão gênica; Rede Genômica Animal; Análise de componentes principais - PCA.; Análise Estatística.; Gene expression; Algorithms; Statistical analysis; Principal component analysis. |
| Ano: 2010 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/883623 |
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| Heslop, David; Roberts, Andrew P.. |
| Principal component analysis (PCA) is a well-established technique in paleomagnetism and provides a means to estimate magnetic remanence directions from univectorial segments of stepwise demagnetization data. Derived directions constrain past geomagnetic field behavior and form the foundation of chronological and tectonic reconstructions. PCA of isolated remanence segments relies on estimates of the segment mean and covariance matrix, which can carry large uncertainties given the relatively small number of demagnetization data points used to characterize individual specimens. Traditional PCA does not, however, lend itself to quantification of these uncertainties, and inferences drawn from paleomagnetic reconstructions suffer from an inability to propagate... |
| Tipo: Text |
Palavras-chave: Paleomagnetism; Directional uncertainty; Principal component analysis. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53255/54707.pdf |
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| Derrien, M.; Jarde, E.; Gruau, G.; Pourcher, A. M.; Gourmelon, Michele; Jadas-hecart, Alain; Wickmann, A. C. Pierson. |
| Improving the microbiological quality of coastal and river waters relies on the development of reliable markers that are capable of determining sources of fecal pollution. Recently, a principal component analysis (PCA) method based on six stanol compounds (i.e. 5 beta-cholestan-3 beta-ol (coprostanol), 5 beta-cholestan-3 alpha-ol (epicoprostanol), 24-methyl-5 alpha-cholestan-3 beta-ol (campestanol), 24-ethyl-5 alpha-cholestan-3 beta-ol (sitostanol), 24-ethyl-5 beta-cholestan-3 beta-ol (24-ethylcoprostanol) and 24-ethyl-5 beta-cholestan-3 alpha-ol (24-ethylepicoprostanol)) was shown to be suitable for distinguishing between porcine and bovine feces. In this study, we tested if this PCA method, using the above six stanols, could be used as a tool in... |
| Tipo: Text |
Palavras-chave: Stanols; Microbial Source Tracking; Principal component analysis; Microbial markers. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00090/20133/17829.pdf |
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| Stefanoski,Diane Cristina; Figueiredo,Cícero Célio de; Santos,Glenio Guimarães; Marchão,Robélio Leandro. |
| Abstract The objective of this work was to assess soil quality indicators obtained with different datasets to compare soil management systems in the Brazilian Cerrado. Three criteria were used to select soil physical, chemical, and biological indicators: the full set of indicators obtained, with 36 parameters, for which all the physical, chemical, and biological soil properties were determined; a subset of indicators selected by principal component analysis (20 parameters); and a subset of indicators with some frequency of use in the literature (16 parameters). These indicators were obtained from the following management systems: no-tillage, conventional tillage, and native cerrado vegetation. Soil samples were collected at 0.0-0.1-m soil depth, and soil... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: No-tillage; Principal component analysis; Soil functioning; Soil health; Soil management; Soil security. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2016000901643 |
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| Aksic,Milica Fotiric; Rakonjac,Vera; Nikolic,Dragan; Zec,Gordan. |
| The objective of this work was to evaluate variability in reproductive biology traits and the correlation between them in genotypes of 'Oblačinska' sour cherry (Prunus cerasus). High genetic diversity was found in the 41 evaluated genotypes, and significant differences were observed among them for all studied traits: flowering time, pollen germination, number of fruiting branches, production of flower and fruit, number of flowers per bud, fruit set, and limb yield efficiency. The number of fruiting branches significantly influenced the number of flower and fruit, fruit set, and yield efficiency. In addition to number of fruiting branches, yield efficiency was positively correlated with fruit set and production of flower and fruit. Results from principal... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Prunus cerasus; Breeding; Genetic divergence; Pollen germination; Principal component analysis; Yield efficiency. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2013000100005 |
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| Nassur,Rita de Cássia Mirela Resende; Pereira,Giuliano Elias; Alves,Juliana Alvarenga; Lima,Luiz Carlos de Oliveira. |
| The objective of this work was to evaluate the influence of different combinations of grape cultivars and rootstocks on chemical characteristics of grape juices. Six treatments were evaluated, consisting of combinations between the Isabel Precoce and BRS Cora grape cultivars and the 'IAC 766', 'IAC 313', and 'IAC 572' rootstocks. Approximately 10 L of juice were obtained per treatment. Analyses of color, total soluble solids content, pH, anthocyanins, total phenolics, total sugars, and quantification and identification of biogenic amines by HPLC were performed. Biogenic amines, such as putrescine, cadaverine, spermidine, and spermine, were found in all evaluated cultivars. By principal component analysis (PCA), treatments can be divided into two groups,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Vitis labrusca; Anthocyanins; Biogenic amines; Phenolics; Principal component analysis. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2014000700540 |
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| Leite,Regina Maria Villas Bôas de Campos; Oliveira,Maria Cristina Neves de. |
| Abstract:The objective of this work was to evaluate the suitability of the multivariate method of principal component analysis (PCA) using the GGE biplot software for grouping sunflower genotypes for their reaction to Alternaria leaf spot disease (Alternariaster helianthi), and for their yield and oil content. Sixty-nine genotypes were evaluated for disease severity in the field, at the R3 growth stage, in seven growing seasons, in Londrina, in the state of Paraná, Brazil, using a diagrammatic scale developed for this disease. Yield and oil content were also evaluated. Data were standardized using the software Statistica, and GGE biplot was used for PCA and graphical display of data. The first two principal components explained 77.9% of the total... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Alternariaster helianthi; Helianthus annuus; Disease resistance; Principal component analysis. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2015000800649 |
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| Novotny,Etelvino Henrique; Auccaise,Ruben; Velloso,Marcia Helena Rodrigues; Corrêa,Juliano Corulli; Higarashi,Martha Mayumi; Abreu,Valéria Maria Nascimento; Rocha,José Dilcio; Kwapinski,Witold. |
| The objective of this work was to develop an alternative methodology to study and characterize the phosphate crystalline properties, directly associated with solubility and plant availability, in biochar from swine bones. Some phosphate symmetry properties of pyrolyzed swine bones were established, using solid state nuclear magnetic resonance spectroscopy, principal component analysis, and multivariate curve resolution analysis, on four pyrolyzed samples at different carbonization intensities. Increasing carbonization parameters (temperature or residence time) generates diverse phosphate structures, increasing their symmetry and decreasing the crossed polarizability of the pair ¹H-31P, producing phosphates with, probably, lower solubility than the ones... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bone phosphate; Phosphate availability; Principal component analysis; Pyrolysis; Multivariedade curve resolution analysis; Soil fertility. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2012000500006 |
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| Balbinot Junior,Alvadi Antonio; Oliveira,Maria Cristina Neves de; Franchini,Julio Cezar; Debiasi,Henrique; Zucareli,Claudemir; Ferreira,André Sampaio; Werner,Flavia. |
| Abstract: The objective of this work was to evaluate how branch and stem variables contribute to grain yield in individual soybean (Glycine max) plants, cultivated at different planting densities, in a modern cultivar with indeterminate growth type. A field experiment was carried out during the 2013/2014 and 2014/2015 crop seasons, in a randomized complete block design with 12 replicates, using the cultivar NK7059 RR at four planting densities: 135, 235, 315, and 440 thousand plants per hectare. Grain yield per plant was evaluated and represented phenotypic plasticity, while the number of branches per plant, percentage of grain production in branches, and separate yield components from branches and stems were considered as the independent variables. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glycine max; Plant density; Principal component analysis; Stepwise regression; Yield components. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018000901038 |
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| Mignani,Luciene; Barbieri,Edison; Marques,Helcio Luis de Almeida; Oliveira,Ana Julia Fernandes Cardoso de. |
| The objective of this work was to evaluate the total and thermotolerant coliform densities in the oyster culture water of Cananeia, SP, Brazil, correlating these densities with environmental variables and tidal variations. Superficial water samples were collected in two tide conditions (spring and neap) from three areas of Cananéia municipality (Mandira, Itapitangui and Cooperostra). The three studied areas showed good conditions for the culture regarding coliform densities. The two tidal conditions differed significantly as to total coliform concentration; however, the same procedure was not performed for thermotolerant coliforms. No correlation was observed between water temperature, pH, and concentrations of total and thermotolerant coliforms. Coliform... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Crassostrea; Contamination; Microbiology; Principal component analysis; Total and thermotolerant coliforms. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2013000800007 |
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| NEJAT,N.; SADEGHI,H.. |
| ABSTRACT Taking into consideration that modeling and indicating relationship among traits and variables are among the most useful numerical techniques in the biological and botanical researches, and also undeniable impact of drought and salinity stresses, this research was implemented with the aim to consider change in relationship among the traits under separately drought and salinity stresses related to scarcely distributed medicinal plant called Christ thorn (Ziziphus spina-christi). A glass house experiment was implemented in controlled conditions at the College of Agriculture, Shiraz University, Shiraz, Iran. Five different water stress levels (irrigation at four, six, eight and 10 days intervals, compared to the unstressed control plants with every... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Salinity; Drought; Stepwise regressions; Principal component analysis; Cluster analysis. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582016000400667 |
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| Registros recuperados: 72 | |
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