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Background: The Gyr breed is widely used in Colombian low tropic dairy production systems. During the last 10 years, the Asociación Colombiana de Criadores de Ganado Cebú† - ASOCEBU, has been leading a dairy milk control program which led to the creation of a dataset that permits to carry out the first analysis of milk yield in Gyr cattle in the country using records from several herds. Objectives: To study milk production dynamics of Gyr cattle in the Colombian low tropic through the estimation of lactation curves and four derived production parameters: total milk yield between 5 and 305 days (TMY305), peak milk yield (PMY), days at peak (DP) and persistency (P). Methods: 13,798 daily milk yield records from 1,510 cows performing in 103 herds were used; the total number of lactations was 2,480. Four models were considered: Wood, Wiltmink, Papajcsik & Bordero, and a second-degree polynomial. Mean square error, mean absolute error, mean square error of prediction, Akaike and Bayesian information criteria were used to select the model better describing each lactation using the majority rule, that is, the model selected by most criteria was the chosen one. The shape of each fitted lactation curve was checked using basic results from calculus which permitted the classification of the estimated curves into two groups: typical and atypical; only typical functions were used to compute the four aforementioned production parameters. Results: The second-order polynomial was the model most frequently selected, while the Papajcsik & Bordero model had the lowest frequency. Average TMY305, PMY, DP and P were 3,489.86 kg, 17.28 kg, 57.17 days, and 0.83, respectively, with coefficients of variation: 0.27, 0.21, 0.41, and 0.16. Conclusions: This study permitted to identify individuals with outstanding phenotypic performance. To the best of our knowledge, this is the first study of this kind involving thousands of lactations from Gyr cows performing in several regions of Colombian low tropic.

Providing a flexible framework for data analysis and model building, this text focuses on the statistical methods and models that can help predict the expected value of an outcome, dependent, or response variable. It offers a sound introduction to general and generalized linear models using the popular and powerful likelihood techniques. The authors enable a clear comparison between general and generalized linear models and cover Gaussian-based hierarchical models and hierarchical generalized linear models. They illustrate the methods with many real-world examples and use R throughout to solve the problems. Ancillaries are available on the book's website.

The success of the first edition of Generalized Linear Models led to the updated Second Edition, which continues to provide a definitive unified, treatment of methods for the analysis of diverse types of data. Today, it remains popular for its clarity, richness of content and direct relevance to agricultural, biological, health, engineering, and other applications.

ABSTRACT When an agricultural experiment is completed and the data about the response variable is available, it is necessary to perform an analysis of variance. However, the hypothesis testing of this analysis shows validity only if the assumptions of the statistical model are ensured. When such assumptions are violated, procedures must be applied to remedy the problem. The present study aimed to compare and investigate how the assumptions of the statistical model can be achieved by classical linear model and generalized linear mixed model, as well as their impact on the hypothesis test of the analysis of variance. The data used in this study was obtained from a genetic breeding program on the cooking time of segregating populations. The following solutions were proposed: i) Classical linear model with data transformation and ii) Generalized linear mixed models. The assumptions of normality and homogeneity were tested by Shapiro-Wilk and Levene, respectively. Both models were able to achieve the assumptions of the statistical model with direct impact on the hypothesis testing. The data transformations were effective in stabilizing the variance. However, several inappropriate transformations can be misapplied and meet the assumptions, which would distort the hypothesis test. The generalized linear mixed models may require more knowledge about the identification of lines of programming, compared to the classical method. However, besides the separation of fixed from random effects, they allow for the specification of the type of distribution of the response variable and the structuring of the residues.

Objective This work sought to determine the association between personal factors and not drinking alcoholic beverages in alcohol-dependent individuals on recovery process. Methods This was a cross-sectional quantitative study. The sample was comprised by 119 adult belonging to 50 Alcoholics Anonymous groups in Saltillo, Coahuila (Mexico). The sampling was simple random, by conglomerates (AA groups). To gather the information, a Personal Data Card was used along with a history on alcohol consumption and the instruments Scale on Social Readjustment Classification, Spiritual Perspective Scale, Schwartz Values Survey, and the Alcohol Use Disorders Identification Test (AUDIT). Results The time without alcohol consumption was related positively with age (r=0.59) and spirituality (r=0.29) and negatively with stressful events (r=-0.31). The Multiple Linear Regression Model explained 32.5% of the variance, with age being the variable remaining in the model and which affected not drinking alcoholic beverages. Conclusion Values and spirituality favor not drinking alcoholic beverages in individuals in the process of recovering from the dependence, while exposure to stressful events increases vulnerability to alcohol consumption. Descriptors: alcoholics anonymous; linear models; social values; alcohol drinking; surveys and questionnaires.

This research approaches the prediction models applied to industrial processes, in order to check the stability of the process by means of control charts, applied to residues from linear modeling. The data used for analysis refers to the moisture content, permeability and compression resistance to the green (RCV), belonging to the casting process of green sand molding in A Company, which operates in the casting and machining, for which dynamic multivariate regression model was set. As the observations were auto-correlated, it was necessary to seek a mathematical model that produces independent and identically distribuibed residues. The models found make possible to understand the variables behavior, assisting in the achievement of the forecasts and in the monitoring of the referred process. Thus, it can be stated that the moisture content is very unstable comparing to the others variables.

En presencia de fallas de mercado, las personas necesitan encontrar mecanismos aceptables que permitan reducir la incertidumbre y maximizar su posible beneficio. Como la principal falla es la asimetría de la información existente, las personas recurren a canales de transmisión de información que compensen las fallas. Estos canales son las redes de relaciones sociales. Esto es el Capital Social, la red de personas que un individuo posee, y cuyo uso puede traerle beneficios. En el caso del mercado financiero (crediticio en especial), las personas hacen uso del Capital Social antes de tomar decisiones dentro del mercado. Mediante una serie de modelos lineales, tomando información de la wvs-2010 y enigh-2010, se encontró que la demanda de crédito responde a algunas variables que muestran la percepción de los individuos sobre su entorno (información). In the presence of market failures, people need to find acceptable mechanisms to reduce uncertainty and maximize potential benefits. Because the principal failure is the asymmetry of information available, people resort to channels that transmit information to compensate for these drawbacks. These channels are networks of social relationships. This phenomenon is referred to as Social Capital, the network of people that an individual possesses, and whose use could bring about benefits. In the case of the financial market (especially the credit market), people make use of Social Capital when making decisions within the market. Through a series of linear models, drawing on data from wvs-2010 and enigh-2010, it was found that credit demand responds to a few variables that indicate individuals’ perceptions of their environment (information). Face à des déficiences du marché, les gens ont besoin de trouver des mécanismes acceptables qui permettent de réduire l’incertitude et de maximiser leur possibilité de bénéfice. Comme la principale déficience est la diversité de l’information existante, les personnes recourent à des canaux de transmission d’information qui compensent les déficiences. Ces canaux sont les réseaux de relation sociale. Ceci est le capital social, le réseau de relations personnelles dont dispose un individu a et dont l’usage peut lui générer des bénéfices. Dans le cas du marché financier (créditeur en particulier), les gens font usage du capital social avant de prendre des décisions vis-à-vis du marché. A travers une série de modèles linéaires, en prenant en compte des informations de la wvs-2010 et enigh-2010, il a été constaté que la demande de crédit répond à certaines variables révélatrices de la perception qu’ont les individus de leur environnement (information). Na presença de falhas de mercado, as pessoas necessitam encontrar mecanismo aceitáveis que permitam reduzir a incerteza e maximizar o seu possível benefício. Como a principal falha é assimetria da informação existente, as pessoas recorrem a canais de transmissão de informação que compensem estas falhas. Estes canais são as redes de relações sociais. Este é o Capital Social, a rede de personas que um indivíduo possui, e cujo uso pode lhe trazer benefícios. No caso do mercado financeiro (creditício em especial), as pessoas usam o Capital Social antes de tomar decisões dentro do mercado. Através de uma série de modelos lineares, tomando informação da wvs- 2010 e enigh-2010, se encontrou que a demanda de crédito responde a algumas variáveis que mostram a percepção dos indivíduos sobre o seu entorno (informação). 面对市场失灵, 人们必须找到其他方法以减少不确定性并将可能受益最大化。由于市场最主要的失灵在于现存信息的不对称性, 人们便寻求其他信息传递的渠道以弥补市场失灵。这些渠道就是社会关系网络, 即社会资本, 也就是一个人所拥有的人脉资源。人脉的运用能够带来利益。就金融市场 (尤其是信贷市场) 而言, 人们在做决定前通常会运用他的社会资本。通过一系列线性模型, 且将2010年wvs模型和2010年enigh模型的信息纳入考虑后, 人们发现, 信贷需求与某些变量相关, 而这些变量反应了个人对其周围信息环境的认识。

The objective of this study was to formulate a mathematical model to estimate digestible energy in animal feeds for tilapia. Literature results were used of the proximate composition of crude protein, ether extract, mineral matter and gross energy, as well as digestible energy obtained in biological assays. The data were subjected to stepwise backward multiple linear regression. Path analysis was performed to measure the direct and indirect effects of each independent variable on the dependent one. To validate the model, data from independent studies and values obtained from a digestibility trial with juvenile Nile tilapia testing five meat and bone meals (MBM) were used, using the Guelph feces collecting system and chromium oxide (III) as an indicator. The obtained model is described below and cannot estimate digestible energy (DE) of animal origin: DE(kcal [kg.sup.-1]) = - 2364.970+ 1.287xGE;[R.sup.2] = 0.775. The path coefficients were medium or low, the highest direct effect was from gross energy (0.529), while the highest indirect effect was from crude protein, through gross energy (0.439). Keywords: nutrition, nutritional value, estimate, linear models. O objetivo deste estudo foi a formulacao de equacoes para estimar a energia digestivel em alimentos para a tilapia. Foram utilizados valores obtidos na literatura da composicao centesimal em proteina bruta, extrato etereo, materia mineral e energia bruta (variaveis independentes), bem como a energia digestivel (variavel dependente) obtidos em ensaios biologicos. Os dados foram submetidos a regressao linear multipla \"stepwise backward\". Foi realizada analise de trilha para medir os efeitos diretos e indiretos de cada variavel independente sobre a dependente. Para validar o modelo foram utilizados dados de estudos independentes, e os valores obtidos em um ensaio de digestibilidade com juvenis de tilapia do Nilo, testando-se cinco farinhas de carne e ossos (FCO), utilizando o sistema de coleta de fezes de Guelph e oxido de cromo (III) como indicador. A equacao obtida nao pode estimar os valores de energia digestivel (ED) de origem animal e esta descrito a seguir: ED(kcal[kg.sup.-1]) = -2364,970 + 1,287xEB;[R.sup.2] = 0,775. Os coeficientes de trilha obtidos tem valores de medios a baixo, sendo o maior efeito direto o da energia bruta (0,529), enquanto a proteina bruta apresentou o maior efeito indireto, via energia bruta (0,439). Palavras-chave: nutricao, valor nutritivo, estimativa, modelos lineares.

ABSTRACT The objective of this study was to apply data transformation via isotonic regression in growth curves studies of Guzerá cattle whose data presented disturbances characterized by decreased body weight in certain age groups. Weight-age data were collected on newly weaned Guzerá males according to the methodology of weight gain tests (WGT) defined by the Brazilian Association of Zebu Breeders (ABCZ). The Logistic, Von Bertalanffy and Gompertz models were fitted to weight-age data using the generalized least squares method for non-linear regression models through the Gauss-Newton algorithm. The proposed transformation based on isotonic regression theory proved to be efficient; and the Logistic model was the best to describe the growth of animals, with a high percentage of convergence (100%) and goodness of fit assessed by the mean squared error (MSE) and the coefficient of determination (R2). RESUMO Objetivou-se aplicar a transformação de dados via regressão isotônica em estudos de crescimento de animais da raça Guzerá cujos dados apresentam distúrbios caracterizados por decréscimos de pesos em determinadas faixas de idades. Foram tomadas observações de peso-idade de machos da raça Guzerá recém-desmamados obedecendo à metodologia das provas de ganho de peso (PGP) definidas pela Associação Brasileira dos Criadores de Zebu (ABCZ). Os modelos Logístico, Von Bertalanffy e Gompertz foram ajustados aos dados de peso-idade por meio do método dos quadrados mínimos ordinários generalizados para modelos de regressão não linear via algoritmo de Gauss-Newton. A transformação proposta por meio da teoria de regressão isotônica mostrou-se eficiente, e o modelo Logístico foi o mais adequado para descrever o crescimento dos animais por apresentar alta porcentagem de convergência (100%) e qualidade de ajuste satisfatória, medida por meio do quadrado médio do erro (QME) e do coeficiente de determinação (R2).

Best Linear Unbiased Prediction (BLUP) has become the most widely accepted method for genetic evaluation of domestic livestock. Since its introduction, the method has evolved and despite this there is no simple text on the application of linear models to the prediction of breeding values. This book has been written with a good balance of theory and application to fill this gap. Equations for partitioning breeding values into contributions from various sources of information are derived under the various models. Recent developments in the analysis of longitudinal data with random regression models and the inclusion of genetic marker information in the evaluation of animals have been incorporated. Overall the book has been thoroughly updated since the first edition was published in 1996.