PREFERENCE HETEROGENEITY AMONG GERMAN CONSUMERS REGARDING GM RAPESEED-OIL

Paper prepared for presentation at the Fourth International Conference on Coexistence between Genetically Modified (GM) and non-GM based Agricultural Supply Chains (GMCC) Melbourne (Australia), 10th to 12th November 2009Genetic engineering, Consumer behaviour, Germany, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, M39, R20,

PERSONAL VALUES OF DIFFERENT USER SEGMENTS OF ETHICAL FOOD PRODUCTS

Consumer/Household Economics,

Indicators of Consumers' Preferences for Bio-Based Apparel: a German Case Study with a Functional Rain Jacket Made of Bioplastic

Plastic pollution is an increasing global problem, however, replacing fossil resources with bioplastics made from renewable resources could be part of the solution. Currently, no research analyzing the influencing factors for consumers' preferences for functional apparel made of bioplastic material could be found. To close this gap in research, we conducted this study with a sample of 1673 participants that were representative of the German population aged 16 years and above. We conducted a choice based conjoint analysis for a bio-based rain jacket and measured psychographic indicators that were used as covariates in the statistical estimation of participants’ preferences for the rain jacket. Our results show the high level of importance of prior product experience, Green Consumer Values and attitude towards bioplastic for selecting bio-based apparel, and thus give first insights related to the influence of psychographic characteristics of consumers when selecting bio-based apparel

ZAHLUNGSBEREITSCHAFT VON KUNDEN IM GÄRTNERISCHEN EINZELHANDEL FÜR PFLANZENTÖPFE AUS NACHWACHSENDEN BZW. RECYCELTEN ROHSTOFFEN

Agribusiness, Consumer/Household Economics, Demand and Price Analysis, Financial Economics, Food Consumption/Nutrition/Food Safety,

Asymptotic normality and efficiency of two Sobol index estimators

International audienceMany mathematical models involve input parameters, which are not precisely known. Global sensitivity analysis aims to identify the parameters whose uncertainty has the largest impact on the variability of a quantity of interest (output of the model). One of the statistical tools used to quantify the influence of each input variable on the output is the Sobol sensitivity index. We consider the statistical estimation of this index from a finite sample of model outputs: we present two estimators and state a central limit theorem for each. We show that one of these estimators has an optimal asymptotic variance. We also generalize our results to the case where the true output is not observable, and is replaced by a noisy version.De nombreux modèles mathématiques font intervenir plusieurs paramètres qui ne sont pas tous connus précisément. L'analyse de sensibilité globale se propose de sélectionner les paramètres d'entrée dont l'incertitude a le plus d'impact sur la variabilité d'une quantité d'intérêt, sortie du modèle. Un des outils statistiques pour quantifier l'influence de chacune des entrées sur la sortie est l'indice de sensibilité de Sobol. Nous considérons l'estimation statistique de cet indice à l'aide d'un nombre fini d'échantillons de sorties du modèle: nous présentons deux estimateurs de cet indice et énonçons un théorème central limite pour chacun d'eux. Nous démontrons que l'un de ces deux estimateurs est optimal en terme de variance asymptotique. Nous généralisons également nos résultats au cas où la vraie sortie du modèle n'est pas observée, mais où seule une version dégradée (bruitée) de la sortie est disponible

Statistical inference for Sobol pick freeze Monte Carlo method

International audienceMany mathematical models involve input parameters, which are not precisely known. Global sensitivity analysis aims to identify the parameters whose uncertainty has the largest impact on the variability of a quantity of interest (output of the model). One of the statistical tools used to quantify the influence of each input variable on the output is the Sobol sensitivity index. We consider the statistical estimation of this index from a finite sample of model outputs. We study asymptotic and non-asymptotic properties of two estimators of Sobol indices. These properties are applied to significance tests and estimation by confidence intervals

Disentangling the Biological and Environmental Control of M. edulis Shell Chemistry

Blue mussel individuals (Mytilus edulis) were cultured at four different salinities (17, 20, 29, and 34). During the course of the experiment, temperature was gradually increased from 6°C to 14°C. Mg/Ca and Sr/Ca ratios of the shell calcite portions produced during the 9 weeks of experimental treatment as well parts that were precipitated before the treatment phase were measured by laser ablation–multicollector–inductively coupled plasma–mass spectrometry. Mg/Ca ratios show a positive correlation with temperature for individuals cultured at salinity 29 and 34 (Mg/Ca (mmol/mol) ∼ (0.2–0.3)*T (°C)), while for individuals cultured at low salinities (17, 20) no trend was observed. Sr/Ca ratios were not affected by temperature but strongly by salinity. The data show very strong biological influence (“individual differences” and “physiological variability”) on elemental ratios (79% on Mg/Ca and 41% on Sr/Ca) in M. edulis calcite. The results challenge the use of blue mussel shell data as environmental proxies