Seleção em diversos ambientes pelo BLP como alternativa à anava conjunta

Plant breeders often carry out genetic trials in balanced designs. That is not always the case with animal genetic trials. In plant breeding is usual to select progenies tested in several environments by pooled analysis of variance (ANOVA). This procedure is based on the global averages for each family, although genetic values of progenies are better viewed as random effects. Thus, the appropriate form of analysis is more likely to follow the mixed models approach to progeny tests, which became a common practice in animal breeding. Best Linear Unbiased Prediction (BLUP) is not a "method" but a feature of mixed model estimators (predictors) of random effects and may be derived in so many ways that it has the potential of unifying the statistical theory of linear models (Robinson, 1991). When estimates of fixed effects are present is possible to combine information from several different tests by simplifying BLUP, in these situations BLP also has unbiased properties and this lead to BLUP from straightforward heuristics. In this paper some advantages of BLP applied to plant breeding are discussed. Our focus is on how to deal with estimates of progeny means and variances from many environments to work out predictions that have "best" properties (minimum variance linear combinations of progenies' averages). A practical rule for relative weighting is worked out.Os melhoristas de plantas em geral conduzem testes genéticos em delineamentos balanceados, ao contrário do que ocorre com o melhoramento animal. É possível selecionar progênies pela ANAVA conjunta, com base nas médias gerais de cada família. Sabe-se, no entanto, que os valores genéticos de progênies são melhor representados por efeitos aleatórios. As formas de análise dos testes de progênie que parecem mais apropriadas são as que seguem a metodologia de modelos mistos, como no melhoramento animal. Segundo Robinson (1991) o Melhor Preditor Linear Não-Viesado (do inglês, BLUP) não é um método, mas uma propriedade dos estimadores (preditores) dos efeitos aleatórios e pode ser derivada de tantas maneiras diferentes que tem o potencial de unificar as teorias estatísticas de modelos lineares. A presença de bons estimadores para os efeitos fixos e componentes da variância torna possível combinar informações de diferentes testes por algumas simplificações do BLUP. Este trabalho exemplifica as vantagens do Melhor Preditor Linear (BLP) aplicado ao melhoramento de plantas. Procurou-se ilustrar como proceder com estimativas de médias e de variâncias de progênies obtidas em diferentes ambientes para produzir preditores que tenham propriedades "melhor" (no sentido de variância mínima entre todas as combinações lineares entre as médias de progênies). Derivou-se uma regra prática para a produção dos pesos relativos de cada ambiente. O BLP, em alguns casos, é também não-viesado produzindo BLUPs a partir de lógica mais direta

Comment on "Universal and accessible entropy estimation using a compression algorithm"

In a recent Letter [1] a framework for estimating entropy was introduced and applied to one-dimensional and two-dimensional systems. In this Comment we show that the method is not well suited for estimating entropy in bidimensional systems presenting long-range correlations.Comment: 2 pages, 1 figur

Therapeutic Indications of the Ketogenic Diet: A Integrative Review

The ketogenic diet (KD), a restrictive diet, is mainly characterized by high-fat content, low or no carbohydrate content, and low or normal protein content. This review aimed to address the main syndromes or diseases in which the therapeutic use of KD can be beneficial. One of the main clinical indications of KD has been, for some time, in the treatment of epilepsy refractory to the use of medications, with satisfactory results in the control of seizures. Recently, studies have addressed the metabolism of ketone bodies caused by KD, in the adjuvant treatment of tumors and endocrine disorders, such as diabetes and obesity, with promising results. In this work, the therapeutic aspect of KD was analyzed, as an aid in the control of pre-existing diseases, and that being a very restrictive diet with controversial effects, its use may be limited and it is not advisable to maintain it for long periods or without the proper follow-up

Estrutura genética de populações de Grevillea robusta A. Cunn. ex. R. Br. estabelecidas no sul do Brasil.

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MARKET ASSISTED LAND REFORM IN NE BRAZIL: A STOCHASTIC FRONTIER PRODUCTION EFFICIENCY EVALUATION

We evaluate the "Cédula da Terra" Pilot Project, a land reform project whose conception, mechanisms and operational structure is different from traditional agrarian reform based on expropriation. The land distributed by the project, is first acquired by the agricultural producers associations, and a given set of incentives is established to obtain a better efficiency use of resources. The main objective of this article is to characterize the sources of technical and allocative inefficiency from a cross section of 309 beneficiaries from five states in NE Brazil. We estimated a potential production frontier following the methodology of BATTESE and COELLI (1995), using the software FRONTIER 4.1. (Tim COELLI, 1996). The main conclusion is that technical assistance, human capital (years of schooling) and better access to credit reduce inefficiency, or thus increase technical and allocative efficiency of the beneficiaries.