Nutrient effects in consumer demand systems: evidence from panel data

This papers aims to analyse the demand for main food groups in Spain. Apart from the traditional economic factors (prices and income), our theoretical framework incorporates the nutrient composition of food into a demand model in the form of food attributes, as a proxy to take into account the rising consumer concern about the relationship between diet and health. A CBS functional form is chosen for the empirical model, which is estimated using a complete panel data set. Ten broad categories, nine nutrients and the most relevant socio-economic variables have been considered. Finally, after employing an appropriate selection strategy, the chosen model is used to calculate expenditure, price and nutrient elasticities, as well as the main socio-demographic effects. Results indicate that the introduction of nutrient-based determinants generates elasticities that differ from those obtained when only economic factors are included, particularly in the case of price elasticities. As the nutrients effect is incorporated in the model through adjusted prices, unhealthier food groups (cereals, white meat and eggs, dairy and sugar) become more inelastic as they are associated with higher perceived prices.     

Estimating Price Elasticities of Food Trade Functions: How Relevant is the CES‐based Gravity Approach?

The main objective of this article is to examine econometric estimates of price elasticities of food trade functions. We investigate the relevance of the prominent gravity approach. This approach is based on the assumptions of symmetric, monotone, homothetic, Constant Elasticity of Substitution (CES) preferences. We test all these assumptions using intra‐European trade in cheese. In general, the assumptions made on preferences by the gravity approach are not supported by our dataset. The bias induced in the estimated price elasticities is ambiguous.     

发酵型鸡油菌孢子饮料的研制

主要探讨了以鸡油菌为原料,利用鸡油菌孢子液体深层发酵,获得菌丝体与发酵液的混合液。通过单因素试验及多因素多水平的正交试验确定出饮料的最佳配方,制作鸡油菌孢子发酵型饮料。对鸡油菌孢子发酵型饮料进行了感官质量的评定,结果表明:发酵120 h时发酵液的感官最好,多糖含量最高,发酵饮料的因素影响主次顺序为发酵液>稳定剂>柠檬酸>白砂糖,发酵饮料的配方以46%的发酵液、0.22%的柠檬酸、0.18%的稳定剂(CMC-Na)、7.5%的白砂糖时制得的发酵饮料品质最佳。     

Why have land use change models for the Amazon failed to capture the amount of deforestation over the last decade?

Land cover change in the Neotropics represents one of the major drivers of global environmental change. Several models have been proposed to explore future trajectories of land use and cover change, particularly in the Amazon. Despite the remarkable development of these tools, model results are still surrounded by uncertainties. None of the model projections available in the literature plausibly captured the overall trajectory of land use and cover change that has been observed in the Amazon over the last decade. In this context, this study aims to review and analyze the general structure of the land use models that have most recently been used to explore land use change in the Amazon, seeking to investigate methodological factors that could explain the divergence between the observed and projected rates, paying special attention to the land demand calculations. Based on this review, the primary limitations inherent to this type of model and the extent to which these limitations can affect the consistency of the projections will also be analyzed. Finally, we discuss potential drivers that could have influenced the recent dynamic of the land use system in the Amazon and produced the unforeseen land cover change trajectory observed in this period. In a complementary way, the primary challenges of the new generation of land use models for the Amazon are synthesized.     

Serial Nonparticipation in Repeated Discrete Choice Models

We consider alternative econometric strategies for addressing serial nonparticipation, that is, repeated choice of the same alternative or same type of alternative across a series of choice occasions, in data typically analyzed within the repeated discrete choice framework. Single and double hurdle variants of the repeated discrete choice model are developed and applied to choice experiment and multisite seasonal recreation demand data. Our results suggest that hurdle models can generate significant improvements in statistical fit and qualitatively different policy implications, particularly in choice experiment applications where the proper treatment of serial nonparticipation is relatively more ambiguous.     

A Note on Estimating Nested Constant Elasticity of Substitution Preferences for Outdoor Recreation

A generalized version of a well-known statistical result is used to suggest an alternative strategy for estimating nested constant elasticity of substitution preferences for recreation demand. Parameter and welfare estimates from nested constant elasticity of substitution count data demand system models are presented and compared to estimates from the multinomial approaches developed previously. A significant advantage of the count data estimation strategy over the multinomial-based approaches is that the analyst avoids the difficulties associated with choice occasion specification and interpretation.     

Recreation Nonparticipation as Choice Behavior Rather Than Statistical Outcome

In recreation demand models nonparticipation is usually estimated as the probability mass on zero demand given a positive level of expected demand and a discrete distribution of demand outcomes. Researchers have attempted to improve predictions of nonparticipation by modifying the parameters of the demand distribution. This study departs from previous approaches by explicitly incorporating nonparticipation into the behavioral model. The choice to participate is described by a distribution of preferences combined with a choke price on individual demands to distinguish participants from nonparticipants. The model is found to accurately predict nonparticipation and the size of the user group.     

The Fast Decay Process in Outdoor Recreational Activities and the Use of Alternative Count Data Models

Despite a number of significant advances in count data modeling during the last two decades and the growing popularity of these models in recreation demand analysis, standard count data models are inadequate to address the fast decay process of the dependent variable and the associated long tail. This article demonstrates how one and two-parameter alternative count data models can be used to properly model the fast decay process and the associated long tail commonly observed in recreation demand analysis. Econometric results from an illustrative application suggest satisfactory performance of four of the eight alternative count data models proposed in this article.     

The Generalized Composite Commodity Theorem and Food Demand Estimation

This article reports tests of aggregation over consumer food products and estimates of aggregate food demand elasticities. Evidence that food demand variables follow unit root processes leads us to build on and simplify existing tests of the Generalized Composite Commodity Theorem. We compute food demand elasticities using a method of cointegration that is shown to apply to a convenient but nonlinear functional form. Estimates are based on consumer reported expenditure data rather than commercial disappearance data.     

高效液相色谱法同时测定含乳饮料中7种合成着色剂

本文建立了高效液相色谱同时检测含乳饮料中7种合成着色剂的方法.以乙酸铵-(甲醇+乙腈)为流动相进行梯度洗脱,样品前处理过程用固相萃取柱处理,含乳饮料中7种色素的回收率在91.4％～107.5％,重复性均<5％.该方法前处理简便,准确度、重复性均良好,可用于7种色素的同时检测.     

Household food consumption in Turkey: a reply

We reply to the Comment by Drichoutis et al. regarding somemethodological and estimation issues arising from our paper.In particular, we compare the elasticities reported in the originalpaper with those obtained using estimation procedures suggestedby Drichoutis et al. We find that the differences are very small.     

Household food consumption in Turkey: a comment

We comment on a recent important article by Akbay et al. anddiscuss some methodological and estimation issues arising fromtheir paper. We then suggest alternative procedures that mayhelp improve their estimates and thereby enhance their usefulnessas a basis for food policy and marketing decisions.     

Concept Optimisation in Innovation Through Conjoint Analysis

Abstract

The objectives of this study were to identify the optimal extrinsic and intrinsic attributes for a range of chilled nutrientenriched orange juice beverages; and to evaluate the contribution of advanced concept optimisation research techniques to new product design and the strategic marketing of innovative functional beverages. A conjointbased survey was administered in both Dublin and Cork between May and September 2004. The results suggested that firms should not rely solely on functionality to leverage a competitive advantage when developing functional beverages. Advanced concept optimisation research techniques contribute towards effective knowledge management in the new product development (NPD) process.     

豆渣在食品工业中的应用研究

豆渣是一种具富含营养价值、尚未得到充分开发利用的食品资源。综述了豆渣的营养价值及其在国内外食品行业的开发利用和研究现状,并阐述了豆渣在食品行业中的发展方向。