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Registros recuperados: 28
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Uso de flunixin meglumine para impedir a regressão prematura de corpos lúteos apos a superovulação em caprinos. Repositório Alice
SOARES, A.T.; SIMPLICIO, A. A.; ANDRIOLI, A.; SALLES, H. O.; MOURA-SOBRINHO, P. A.; SOARES, B. A.; MORAES, J. B.; WANDERLEY, K. O..
A alta incidências de corpos lúteos prematuramente regredidos após tratamento superovulatório com FSH em cabras resulta em baixa taxa de recuperação de embriões. Este fato ressalta a importância de tratamentos que impeçam ou minimizem a regressão. O uso de tlunixin meglumine tem sido relatado na literatura como medicamento capaz de impedir a regressão prematura de corpos lúteos por ter ação anti-prostaglandina. 0 objetivo deste experimento foi testar três doses de flunixin meglumine e compará-las ao controle, para avaliar sua real eficácia e quaI a dose custo mais efetiva. Foram utilizadas 31 cabras mestiças, sob estro sincronizado corn esponjas vaginais (11 dias) impregnadas com 60 mg de acetato de medroxiprogesterona, sendo aplicado 50mg de cloprostenol...
Tipo: Resumo em anais de congresso (ALICE) Palavras-chave: Regressão; Regression; Caprino; Superovulação; Corpo lúteo; Dose; Hormônio animal; Flunixin; Goats; Drugs; Superovulation; Corpus luteum hormones.
Ano: 1995 URL: http://www.alice.cnptia.embrapa.br/handle/doc/514221
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Parametros de estabilidade em cultivares de algodoeiro herbaceo avaliadas na regiao nordeste do Brasil. Repositório Alice
FARIAS, F.J.C.; RAMALHO, M.A.P.; CARVALHO, L.P. de; MOREIRA, J. de A.N..
Foram avaliados os dados de produtividade de algodao em caroco em 56 experimentos de avaliacao de cultivares, conduzidos na Regiao Nordeste, no periodo de 1985 a 1992, visando estimar os parametros de estabilidade e adaptabilidade e verificar se eles sao herdaveis. Utilizou-se o metodo de Silva Barreto (1985), modificado por Cruz et al. (1989). A repetibilidade foi estimada segundo o procedimento utilizado por Santos et al. (1982). As cultivares CNPA 3H, CNPA 83-180, CNPA TH, IAC 20, CNPA 7H E CNPA 85-241 sao as mais adaptaveis e estaveis, enquanto A HR 102, BR-1, CNPA Giorge I e CNPA Precoce I sao as mais estaveis em ambientes desfavoraveis, porem com baixa produtividade. De maneira geral, os materiais apresentaram alta previsibilidade de comportamento,...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Algodao; Regressao; Repetibilidade; Cotton crop; Regression; Repeatability.
Ano: 1996 URL: http://www.alice.cnptia.embrapa.br/handle/doc/104159
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Explaining dinophysis cf. acuminata abundance in Antifer (Normandy, France) using dynamic linear regression ArchiMer
Soudant, Dominique; Beliaeff, Benoit; Thomas, G.
Classical regression analysis can be used to model time series. However, the assumption that model parameters are constant over time is not necessarily adapted to the data. In phytoplankton ecology, the relevance of time-varying parameter values has been shown using a dynamic linear regression model (DLRM). DLRMs, belonging to the class of Bayesian dynamic models, assume the existence of a non-observable time series of model parameters, which are estimated on-line, i.e. after each observation. The aim of this paper was to show how DLRM results could be used to explain variation of a time series of phytoplankton abundance. We applied DLRM to daily concentrations of Dinophysis cf. acuminata, determined in Antifer harbour (French coast of the English...
Tipo: Text Palavras-chave: Phytoplankton; Dinophysis; Time series; Regression; Dynamic; Bayesian.
Ano: 1997 URL: http://archimer.ifremer.fr/doc/00337/44784/44490.pdf
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Relação entre medidas corporais e peso vivo em caprinos das racas Saanen e Anglo-Nubiana. Repositório Alice
TEIXEIRA, M. P. B.; BARROS, N. N.; ARAUJO, A. M. de.; SELAIVE VILLAROEL, A..
Vinte e sete femeas jovens, sendo dez da raça Saanen e dezessete da raça Anglo-nubiana, foram analisadas de acordo com suas características de peso vivo (PV), perímetro tonicico (PT), perimetro abdominal (PA), altura da cernelha (AC) e comprimento corporal (CC). As avaliações foram feitas entre as idades de sete e 224 dias. As correlações fenotípicas entre as medidas estudadas e entre estas e o peso corporal foram positivas e altamente significativas (p<0,0001). As equações de regressao estabelecidas mostraram que todas as medidas estudadas podem ser utilizadas para estimar 0 peso corporal. Todavia, 0 perimetro tonicico forneceu o melhor indicador de peso vivo.
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Caprino leiteiro; Raca; Saanen; Anglo-Nubiana; Medida corporal; Peso vivo; Correlacao; Morfometria; Regressao; Goat; Morphometry; Correlation; Regression; Live weight; Body measurements.
Ano: 2000 URL: http://www.alice.cnptia.embrapa.br/handle/doc/528207
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Research of quality indices for cold-smoked salmon using a stepwise multiple regression of microbiological counts and physico-chemical parameters ArchiMer
Leroi, Francoise; Joffraud, Jean-jacques; Chevalier, Frederique; Cardinal, Mireille.
Aims: The aim of the study was to assess the relationships between the remaining shelf-life (RSL) of cold-smoked salmon and various microbiological and physico-chemical parameters, using a multivariate data analysis in the form of stepwise forward multiple regression. Methods and Results: Thirteen batches of French cold-smoked salmon were analysed weekly during vacuum-packed storage at 5 degreesC for their lipid, water, salt, phenol, pH, total volatile basic nitrogen (TVBN) and trimethylamine contents, total psychrotrophic count, lactic acid bacteria, lactobacilli, B. thermosphacta, Enterobacteriaceae and yeast counts. At the sensory rejection time, the flora was dominated by lactobacilli, lactobacilli/Enterobacteriaceae or Carnobacteria/B. thermosphacta....
Tipo: Text Palavras-chave: Microbiological; Parameters; Regression; Cold smoked salmon.
Ano: 2001 URL: http://archimer.ifremer.fr/doc/2001/publication-609.pdf
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Choosing an appropriate real-life measure of effect size: the case of a continuous predictor and a binary outcome AgEcon
Conroy, Ronan M..
A case study of data on age and pregnancy is used to point up some morals for practicing data analysts, including the superiority of regression over t tests, exploratory scatterplot smoothing as a key method of checking form of relationship, and the value of logistic regression followed by adjust as a way of getting at the numbers of most interest.
Tipo: Journal Article Palavras-chave: Adjust; Correlation; Logistic regression; Regression; Scatterplot smoothing; T tests; Research Methods/ Statistical Methods.
Ano: 2002 URL: http://purl.umn.edu/116011
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Speaking Stata: Graphing model diagnostics AgEcon
Cox, Nicholas J..
Plotting diagnostic information calculated from residuals and fitted values is a long-standard method for assessing models and seeking ways of improving them. This column focuses on the statistical mainstream defined by regression models for continuous responses, treated in a broad sense to include (for example) generalized linear models. After some comments on the history of such ideas (and even their anthropology and psychology), the commands available in official Stata are reviewed, and a modeldiag package is introduced. A detailed example on fuelwood yield from fallow areas in Nigeria illustrates a variety of general points and specific tips.
Tipo: Journal Article Palavras-chave: Modeldiag; Anovaplot; Indexplot; Ofrtplot; Ovfplot; Qfrplot; Racplot; Rdplot; Regplot; Rhetplot; Rvfplot2; Rvlrplot; Rvpplot2; Graphics; Diagnostics; Regression; Generalized linear models; Analysis of variance; Research Methods/ Statistical Methods.
Ano: 2004 URL: http://purl.umn.edu/116273
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Lamb meat tenderness prediction using neural networks and sensitivity analysis IPB - Escola Superior Agrária
Cortez, Paulo; Portelinha, Manuel; Rodrigues, Sandra; Cadavez, Vasco; Teixeira, A..
The assessment of quality is a key factor for the meat industry, where the aim is to fulfill the consumer’s needs. In particular, tenderness is considered the most important characteristic affecting consumer perception of taste. In this paper, a Neural Network Ensemble, with feature selection based on a Sensitivity Analysis procedure, is proposed to predict lamb meat tenderness. This difficult real-world problem is defined in terms of two regression tasks, by using instrumental measurements and a sensory panel. In both cases, the proposed solution outperformed other neural approaches and the Multiple Regression method.
Tipo: Article Palavras-chave: Regression; Multilayer perceptrons; Multiple regression; Meat quality; Ensembles; Data mining.
Ano: 2005 URL: http://hdl.handle.net/10198/865
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Lamb meat quality assessment by support vector machines IPB - Escola Superior Agrária
Cortez, Paulo; Portelinha, Manuel; Rodrigues, Sandra; Cadavez, Vasco; Teixeira, A..
The correct assessment of meat quality (i.e., to fulfill the consumer's needs) is crucial element within the meat industry. Although there are several factors that affect the perception of taste, tenderness is considered the most important characteristic. In this paper, a Feature Selection procedure, based on a Sensitivity Analysis, is combined with a Support Vector Machine, in order to predict lamb meat tenderness. This real-world problem is defined in terms of two difficult regression tasks, by modeling objective (e.g. Warner-Bratzler Shear force) and subjective (e.g. human taste panel) measurements. In both cases, the proposed solution is competitive when compared with other neural (e.g. Multilayer Perceptron) and Multiple Regression approaches.
Tipo: Article Palavras-chave: Regression; Multilayer perceptrons; Support vector machines; Meat quality; Data mining; Feature selection.
Ano: 2006 URL: http://hdl.handle.net/10198/858
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HEDGE DINÂMICOS: UMA EVIDÊNCIA PARA OS CONTRATOS FUTUROS BRASILEIROS AgEcon
Bitencourt, Wanderci Alves; Silva, Washington Santos; Safadi, Thelma.
The farming sector is changing, growing and occupying a position of prominence in the economy. These transformations start to demand a bigger concern with the management of risks of the activity. In this direction, the contracts traded at BM&F had become efficient instruments in the reduction of the market risk, through an operation called hedge. However, there is still the necessity of improving of the econometrical techniques for the estimation of the optimal hedge ratio, therefore, it is observed in the brazilian literature that the majority of the works doesn’t consider some aspects of the behavior of the series of returns. Thus, the present work seeks to analyze two methods for the calculation of these hedge optimal ratio, the conventional model...
Tipo: Journal Article Palavras-chave: Hedge optimal ratio; GARCH BEKK model; Regression.
Ano: 2006 URL: http://purl.umn.edu/43828
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Seleção de variáveis em modelos matemáticos dos parâmetros de cultivo do camarão marinho Litopenaeus vannamei. Repositório Alice
BEZERRA, A.M.; SILVA, J.A.A. da; MENDES, P. de P..
O objetivo deste trabalho foi selecionar as variáveis de manejo do camarão marinho Litopenaeus vannamei que mais influenciaram nas variáveis-respostas ao cultivo (produção, produtividade, peso final e taxa de sobrevivência), em modelos matemáticos. O banco de dados foi composto por 83 cultivos, realizados no período de 2003 a 2005, obtidos de uma fazenda comercial localizada no litoral sul de Pernambuco. Para estimar os parâmetros dos modelos, utilizou-se a técnica dos mínimos quadrados. A seleção das variáveis foi realizada com o processo "backward elimination" associado ao método de transformação de Box e Cox. A adequação das equações e os pressupostos de normalidade e homocedasticidade, para os erros, foram analisadas com base na análise de variância e...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Criação; Regressão; Box; Cox; Stepwise; Rearing; Regression; Box; Cox; Stepwise.
Ano: 2007 URL: http://www.alice.cnptia.embrapa.br/handle/doc/123792
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Predicción del rendimiento en cortes, hueso y grasa en búfalos de agua en Venezuela Repositório Alice
ATENCIO-VALLADARES, O.; HUERTA-LEIDNZ, N.; RODAS-GONZÁLEZ, A.; JEREZ-TIMAURE, N..
Los objetivos de este estudio fueron determinar la asociación entre rasgos de la canal y el rendimiento en cortes (RCD), rendimiento en hueso y recortes de grasa en búfalos de agua, y desarrollar ecuaciones predictivas para cada variable mencionada. Se utilizaron 48 búfalos de agua (24 castrados y 24 enteros), sacrificados a los 17, 19 y 24 meses de edad con mestizaje de razas Murrah y Mediterránea. Se evaluaron las variables de la canal y del rendimiento en cortes. Se realizaron: pruebas descriptivas, análisis de correlación, residuos y de regresión lineal múltiple. En los castrados, el acabado de grasa y la circunferencia del muslo explicaron la mayor variación en RCD. El espesor de grasa y el porcentaje de grasa renal fueron las variables mayormente...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Bubalus bubalis; Regresión; Ecuaciones de predicción; Rendimiento cárnico; Regression; Retail yield cuts; Predictive equations.
Ano: 2007 URL: http://www.alice.cnptia.embrapa.br/handle/doc/122857
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SIND BETRIEBSGEMEINSCHAFTEN WIRTSCHAFTLICHER ALS EINZELBETRIEBE? AgEcon
Lips, Markus; Pulfer, Iris; Messer, Martin.
The influence of farming collectives on income per annual work unit (AWU) is investigated by means of regressions for three types of farms with animal husbandry. The effects are relatively small, and turn out differently for the three farm types. Whereas the effect is negative for the dairy farms (-1200 CHF), collective farming in the case of combined dairying/arable-crop farms and combined pig/poultry farms leads to a higher income (+900 and +500 CHF, respectively). The latter two farm types are characterised by at least two important production branches, unlike the dairy farms, which have just one. The result for the dairy farms, however, does not call the farming collective into question as a growth opportunity. The usual scale effects that can be...
Tipo: Conference Paper or Presentation Palavras-chave: Betriebsgemeinschaft; Einzelbetrieb; Einkommen; Regression; Schweiz; Farming collectives; Income; Individual farm; Switzerland; Agribusiness; Farm Management.
Ano: 2007 URL: http://purl.umn.edu/7617
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Farmer-to-Consumer Direct Marketing: The Role of Customer Satisfaction Measurement for Service Innovations AgEcon
Spiller, Achim; Zuhlsdorf, Anke; Mellin, Matthias.
The importance of direct marketing for high quality farm products has increased during the past few years. This paper analyses the impact of customer satisfaction and its driving forces for farmer- to-consumer direct marketing and is based on a customer survey in 33 organic and conventional on-farm stores in Germany. The results emphasise the role of store atmosphere and customer service as the main influencing factors on customer satisfaction.
Tipo: Conference Paper or Presentation Palavras-chave: Direct Marketing; Customer satisfaction; Regression; Service Quality; Agribusiness; Marketing.
Ano: 2007 URL: http://purl.umn.edu/6607
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Causal inference with observational data AgEcon
Nichols, Austin.
Problems with inferring causal relationships from nonexperimental data are briefly reviewed, and four broad classes of methods designed to allow estimation of and inference about causal parameters are described: panel regression, matching or reweighting, instrumental variables, and regression discontinuity. Practical examples are offered, and discussion focuses on checking required assumptions to the extent possible.
Tipo: Article Palavras-chave: Xtreg; Psmatch2; Nnmatch; Ivreg; Ivreg2; Ivregress; Rd; Lpoly; Xtoverid; Ranktest; Causal inference; Match; Matching; Reweighting; Propensity score; Panel; Instrumental variables; Excluded instrument; Weak identification; Regression; Discontinuity; Local polynomial; Research Methods/ Statistical Methods.
Ano: 2007 URL: http://purl.umn.edu/119292
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Creating print-ready tables in Stata AgEcon
Lokshin, Michael; Sajaia, Zurab.
This article describes the new Stata command xml_tab, which outputs the results of estimation commands and Stata matrices directly into tables in XML format. The XML files can be opened with Microsoft Excel or OpenOffice Calc, or they can be linked with Microsoft Word files. By using XML, xml_tab allows Stata users to apply a rich set of formatting options to the elements of output tables.
Tipo: Article Palavras-chave: Xml_tab; Estimates; Regression; Matrices; Xml; Excel; Word; Research Methods/ Statistical Methods.
Ano: 2008 URL: http://purl.umn.edu/122600
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Erratum and discussion of propensity–score reweighting AgEcon
Nichols, Austin.
Tipo: Article Palavras-chave: Xtreg; Psmatch2; Nnmatch; Ivreg; Ivreg2; Ivregress; Rd; Lpoly; Xtoverid; Ranktest; Causal inference; Match; Matching; Reweighting; Propensity score; Panel; Instrumental variables; Excluded instrument; Weak identification; Regression; Discontinuity; Local polynomial; Research Methods/ Statistical Methods.
Ano: 2008 URL: http://purl.umn.edu/122619
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Efficiency and sustainability assessment for a group of farmers in the Brazilian Amazon. Repositório Alice
GOMES, E. G.; MELLO, J. C. C. B. S. de; SOUZA, G. da S. e; MEZA, L. A.; MANGABEIRA, J. A. de C..
The aim of this paper is to use DEA models to evaluate sustainability in agriculture. Several variables are taken into account and the resulting efficiency is measured by comparison. The performance of family farms is analysed here (variables: farmed area, work force, and production). As agricultural sustainability depends on the maintenance of systems of production for long periods of time, the models were run for the years of 1986 and 2002. Tiered DEA models were used to group farmers in sustainability categories. Non-parametric regression models were used to identify the factors affecting the efficiency measurements. All the results indicate that the majority of the farmers increased their efficiency along the time. These improvements may support the...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Data envelopment analysis; Iso - efficiency tiers; Regression; Family farms..
Ano: 2009 URL: http://www.alice.cnptia.embrapa.br/handle/doc/657362
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Efficiency and sustainability assessment for a group of farmers in the Brazilian Amazon. Repositório Alice
GOMES, E. G.; MELLO, J. C. C. B. S. de; SOUZA, G. da S. e; MEZA, L. A.; MANGABEIRA, J. A. de C..
The aim of this paper is to use DEA models to evaluate sustainability in agriculture. Several variables are taken into account and the resulting efficiency is measured by comparison. The performance of family farms is analyzed here (variables: farmed area, work force, and production). As agricultural sustainability depends on the maintenance of systems of production for long periods of time, the models were run for the years of 1986 and 2002. Tiered DEA models were used to group farmers in sustainability categories. Non-parametric regression models were used to identify the factors affecting the efficiency measurements. All the results indicate that the majority of the farmers increased their efficiency along the time. These improvements may support the...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Data envelopment analysis; Iso - efficiency tiers; Regression; Family farms.
Ano: 2009 URL: http://www.alice.cnptia.embrapa.br/handle/doc/32105
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Estimation of light lamb carcass composition by in vivo real-time ultrasonography at four anatomical locations IPB - Escola Superior Agrária
Ripoll, G.; Joy, M.; Álvarez-Rodríguez, J.; Sanz, B.; Teixeira, A..
The objectives of this study were to study the relationship between in vivo ultrasound measurements and cold carcass measurements at 4 anatomical points of the backbone, and to establish regression equations to estimate carcass composition within the cold carcass weight range for Ternasco lambs (8 to 12.5 kg) by using ultrasonic measurements taken at a single location. Measurements of subcutaneous fat and skin thickness and of muscle depth and width were taken over the 10th to 11th and 12th to 13th thoracic vertebrae and the 1st to 2nd and 3rd to 4th lumbar vertebrae. These measurements were taken at 2 and 4 cm from the nearest end of the LM to the backbone and at 1/3 of the LM width with the probe perpendicular to and parallel to the backbone. The left...
Tipo: Article Palavras-chave: Carcass composition; Fat thickness; Muscle depth; Prediction; Regression; Ultrasound.
Ano: 2009 URL: http://hdl.handle.net/10198/4907
Registros recuperados: 28
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