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An Appraisal of Beekeeping Activities among Beneficiaries and Non-Beneficiaries of Ekiti State Agricultural Credit Agency (ESACA) Scheme in Nigeria AgEcon
Fakayode, S.B.; Babatunde, Raphael O.; Olowogbon, S.T.; Adesuyi, W.S..
The study examined beekeeping activities in Ekiti State, Nigeria. Specifically the study appraised the costs and returns structure of beekeeping activities by beneficiaries of the ESACA scheme, examined the constraints to beekeeping under the scheme and outside the scheme and identified factors that affect beekeeping under the scheme and outside the scheme. A total of 150 beekeeper households were selected; 75 households each for ESACA beneficiary and non-beneficiary respondents across communities popularly known for beekeeping in Ekiti state. Descriptive statistics, costs and returns, regression and Kruscalwallis analyses were employed for data analysis. Beekeeping was found to be more profitable under the ESACA scheme than outside the scheme with returns...
Tipo: Conference Paper or Presentation Palavras-chave: Kruscal-wallis; Costs and returns structure; Regression; Technical assistance; Crop Production/Industries; Livestock Production/Industries.
Ano: 2010 URL: http://purl.umn.edu/95785
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Assessing the determinants of rural income dispersion in Brazil. Repositório Alice
SOUZA, G. da S. e; GOMES, E. G.; ALVES, E. R. de A..
This article has as its objective the analysis of rural income dispersion in Brazil. To this en we fit econometric regression models using the Gini index as the dependent variable, tecnology, and environmental, social and demographic indices as independent variables. The analysis is performed on a regional basis. The statistical approach uses fractional regression and generalized method of moments 9GMM) The tecnological variable crystallizes the production process uses county data collected from the Brazilian agricultural census of 2006. Tecnology is significant and dominates the relationship in all regions. The other covariates vary in regional intensity.
Tipo: Artigo em anais de congresso (ALICE) Palavras-chave: Income concentration; Agriculture; Regression; GMM; Pesquisa agrícola.
Ano: 2015 URL: http://www.alice.cnptia.embrapa.br/handle/doc/1035777
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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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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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Combined index of genomic prediction methods applied to productivity traits in rice. Repositório Alice
SUELA, M. M.; LIMA, L. P.; AZEVEDO, C. F.; RESENDE, M. D. V. de; NASCIMENTO, M.; SILVA, F. F. e.
A cultura do arroz tem grande importância nacional e mundial por ser um dos cereais mais produzidos e consumidos no mundo, caracterizando-se como o principal alimento de mais da metade da população mundial. Em função de sua importância alimentar, desenvolver métodos eficientes que visam a predição e a seleção de indivíduos geneticamente superiores, quanto a características da planta, é de extrema importância para os programas de melhoramento. Diante disso, o objetivo deste trabalho foi avaliar e comparar a eficiência do método Delta-p, G-BLUP, BayesCpi, BLASSO e o índice Delta-p/G-BLUP, índice Delta-p/BayesCpi e índice Delta-p/BLASSO, na estimação de valores genômicos e dos efeitos de marcadores SNPs (Single Nucleotide Polymorphisms) em dados fenotípicos...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Predição genômica; Ganho genético; Genomic prediction; Genetic gain; Bayesian alphabet; Molecular bases; Regression; Índice de Seleção; Selection index.
Ano: 2019 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1110881
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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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Development of empirical regression equations for predicting the performances of disc plough and harrow in clay-loam soil CIGR Journal
Oduma, Okechukwu.
Abstract: The regression equations for predicting the performances of plough and harrow implements in clay – loam soil in South – East agro – ecological region of Nigeria were developed. This is to enable farmers, farm managers and users of farm machinery assess and select proper machinery based on soil type/ condition for good performance of the machine and to avoid unnecessary breakdown/failures or energy loss during operation and generally to optimize production at minimum cost. Results showed that for plough operated in clay – loam soil, the regression equation that can predict its various performance indicators are: field efficiency, Y = 0.067x2 – 0.7733x + 89.283; effective field capacity, Y = 0.0864x2 – 1.4406x +6.8173; theoretical field capacity, Y...
Tipo: Info:eu-repo/semantics/article Palavras-chave: AGRICULTURAL AND BIORESOURCES ENGINEERING Keywords: empirical; Harrow; Plough; Performances; Regression; Soil type..
Ano: 2019 URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/5390
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Dislocation and Regression of the Role of Collective in Land Transfer AgEcon
Xu, Wei; Yuan, Jingheng.
This paper expounds the origin of "collective" in the process of collective land transfer, and analyzes the dislocation phenomenon of the role of collective in the process of collective land transfer as follows: deviation of the role under the conflict of identity; offside of the role under the limitation of democratic construction; omission of the role under the segmentation of interests. In order to protect me legitimate rights of farmers, we should make the role of collective to revert on the basis of township government, farmer and collective, so that the role of collective is restored under the management of government; the role of collective reverts under the supervision of farmers; the role of collective returns under its own strengthening of...
Tipo: Journal Article Palavras-chave: Land transfer; Role of collective; Dislocation; Regression; China; Agribusiness.
Ano: 2011 URL: http://purl.umn.edu/118289
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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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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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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
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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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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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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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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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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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Methods for the determination of carbon in Ultisol in eastern Amazon. Repositório Alice
RODRIGUES, S. J. S. de C.; VASCONCELOS, S. S.; PEREIRA, M. E. M.; SOUZA, C. M. de A..
O teor de carbono (C) no solo é um indicador sensível de impacto de manejo agrícola. Diferentes métodos são atualmente adotados para determinar o teor de C do solo, o que pode levar a resultados variados e, dessa maneira, dificultar a interpretação dos impactos do manejo. Neste estudo, testamos três métodos de determinação de C comumente usados (combustão via seca em analisador elementar, combustão via seca por perda de massa por ignição e combustão via úmida), com amostras de solo de áreas agrícolas sob diferentes manejos (preparo de área com e sem queima) e de floresta. O método de combustão via úmida subestimou o teor de C do solo em relação ao método padrão (combustão via seca em analisador elementar). Encontramos altos coeficientes de determinação das...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Carbono orgânico; Combustão via seca; Combustão via úmida; Regressão; Perda de massa por ignição; Organic carbon; Dry combustion; Wet combustion; Mass loss-on-ignition; Regression.
Ano: 2013 URL: http://www.alice.cnptia.embrapa.br/handle/doc/987550
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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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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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