Transmissão de preços e cointegração no mercado brasileiro de arroz

O objetivo do presente trabalho foi avaliar a dinâmica de formação de preços no mercado nacional de arroz em casca de modo a definir o processo de formação e intensidade do ajustamento (períodos em que se dá a transmissão de preços) entre os principais mercados produtores (RS e MT). O conhecimento das relações de preços entre os mercados importante para o desenvolvimento de contratos de comercialização (contratos a termo e de futuro) para o arroz e para a formulação (ou reformulação) de políticas públicas para o setor. Como instrumental metodológico utilizou-se da modelagem de sries temporais (Modelos de Autorregressão Vetorial com Correção de Erro (VEC)) e causalidade de Granger. O resultado do teste de causalidade de Granger apontou que os preços do RS são importantes para prever os preços de MT. O modelo de transferência estimado com correção de erro mostrou que, para cada 1% de aumento na taxa de crescimento dos preços no RS, a taxa de crescimento dos preços em MT registrará, em mdia, aumento contemporâneo de 0,44% e em torno de 0,17% com um período de defasagem.<br>The aim of this study is to evaluate the dynamics of pricing in the domestic market of paddy rice in order to define the process of prices formation and the adjustment intensity (periods in which the price transmission occurs) among the major producing markets (Rio Grande do Sul and Mato Grosso states). The knowledge of price ratios between markets is important for the development of trading contracts (fixed-term and future contracts) for rice and for the formulation (or reformulation) of public policies for the sector. As a methodological tool, we used the modeling of time series (Auto-Regression Models with Vector Error Correction - VEC) and Granger' causality. The Granger' causality test indicated that prices in the Rio Grande do Sul state are important to forecast prices in the Mato Grosso state. The model of transference estimated with an error correction term showed that for each 1% of increase in the growth rate for the RS prices, the growth rate of prices in MT will have, on average, a contemporaneous high of 0.44%, and around 0.17% in the following month

The value of genetic resources in agriculture: a meta-analysis assessing existing knowledge and future research needs

The protection of genetic resources in agriculture is an important aspect of biodiversity conservation. Knowledge of the value of genetic resources can contribute to determining the appropriate focus and extent of conservation. This study reviewed and summarised literature on the economic value of genetic resources using meta-analysis. Altogether, 22 studies were used to describe current knowledge on the value of genetic resources. Furthermore, 14 studies with 93 value observations were examined with a meta-regression model to identify variables that explain the willingness-to-pay (WTP) for or willingness-to-accept (WTA) loss of genetic resources. Grain genetic resources were ascribed lower value compared to animal genetic resources (AnGR) and agrobiodiversity, and the values of breeds or varieties and conservation programmes were higher than the value of individual attributes. Future research should address the gaps in knowledge that are relevant for policy-making. This particularly includes improving knowledge on the value of plant genetic resources (PGR), obtaining value estimates for maintaining genetic diversity in Europe and the United States, estimating the relative magnitude of use and non-use values and determining the value consumers place on genetic resources and diversity in agriculture. An extensive database with valuation literature on genetic resources that fulfils the requirements for benefit transfer is essential to utilise value information more efficiently in decision-making situations.v2011o