Deciphering the Anti-Aflatoxinogenic Properties of Eugenol Using a Large-Scale q-PCR Approach

Produced by several species of Aspergillus, Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin contaminating many crops worldwide. The utilization of fungicides is currently one of the most common methods; nevertheless, their use is not environmentally or economically sound. Thus, the use of natural compounds able to block aflatoxinogenesis could represent an alternative strategy to limit food and feed contamination. For instance, eugenol, a 4-allyl-2-methoxyphenol present in many essential oils, has been identified as an anti-aflatoxin molecule. However, its precise mechanism of action has yet to be clarified. The production of AFB1 is associated with the expression of a 70 kB cluster, and not less than 21 enzymatic reactions are necessary for its production. Based on former empirical data, a molecular tool composed of 60 genes targeting 27 genes of aflatoxin B1 cluster and 33 genes encoding the main regulatory factors potentially involved in its production, was developed. We showed that AFB1 inhibition in Aspergillus flavus following eugenol addition at 0.5 mM in a Malt Extract Agar (MEA) medium resulted in a complete inhibition of the expression of all but one gene of the AFB1 biosynthesis cluster. This transcriptomic effect followed a down-regulation of the complex composed by the two internal regulatory factors, AflR and AflS. This phenomenon was also influenced by an over-expression of veA and mtfA, two genes that are directly linked to AFB1 cluster regulation

Méthode multicritère de sélection de portefeuilles indiciels internationaux

Dans cet article nous présentons une méthode multicritère permettant de sélectionner des portefeuilles indiciels internationaux formés à partir des indices boursiers de seize (16) pays. La première version de cette méthode (ELECTRE IS) permet d’identifier les portefeuilles candidats pour le choix final (noyau) et de les comparer à ceux de la frontière efficiente traditionnelle. La deuxième version (ELECTRE III) classe tous les portefeuilles envisagés du meilleur au moins désirable, à partir des préférences de l’investisseur révélées à travers les divers paramètres de la méthode.In this paper, we present a multicriterion approach of portfolio comparison and apply it to the selection of a global index fund portfolio using sixteen (16) national stock market indexes. The first algorithm used in the study (ELECTRE IS) solves for the subset of portfolios among which the investor must limit his choice (the Kernel). These portfolios can then be contrasted with those of the traditional efficient set. The second algorithm (ELECTRE III) ranks all the portfolios considered from best to worst, on the basis of investor's preferences revealed through the various parameters used in the calculations

Comparaison performance-taille des fonds mutuels par une analyse multicritère

L’objet de cette étude est de vérifier si certaines caractéristiques de « risque et de rendement » des fonds mutuels sont clairement reliées à la taille de ces fonds. On se place donc dans un contexte multidimensionnel, où l’on cherche à prendre simultanément en compte les diverses caractéristiques d’un tel placement. Cette vérification est effectuée à l’aide d’une analyse multicritère s’inspirant de la méthode PROMETHEE, laquelle se fonde sur des relations de surclassement.Ce type d’analyse permet également d’expliciter l’impact que peut avoir l’importance relative accordée aux critères, sur la performance des fonds.The purpose of this paper is to verify if some risk-return characteristics of mutual funds are clearly related to their size. Assuming a multidimensional setting where various funds characteristics can be explicitly and simultaneously considered. The paper applies PROMETHEE methodology, based on outranking relations, to make this verification.Such a multicriterion analysis also allows an explicit measure of the impact of the weight given to each criterion on the performance of the funds

Does Dehazing Model Preserve Color Information?

International audience—Image dehazing aims at estimating the image information lost caused by the presence of fog, haze and smoke in the scene during acquisition. Degradation causes a loss in contrast and color information, thus enhancement becomes an inevitable task in imaging applications and consumer photography. Color information has been mostly evaluated perceptually along with quality, but no work addresses specifically this aspect. We demonstrate how dehazing model affects color information on simulated and real images. We use a convergence model from perception of transparency to simulate haze on images. We evaluate color loss in terms of angle of hue in IPT color space, saturation in CIE LUV color space and perceived color difference in CIE LAB color space. Results indicate that saturation is critically changed and hue is changed for achromatic colors and blue/yellow colors, where usual image processing space are not showing constant hue lines. we suggest that a correction model based on color transparency perception could help to retrieve color information as an additive layer on dehazing algorithms

A Color Image Database for Haze Model and Dehazing Methods Evaluation

International audienceOne of the major issues related to dehazing methods (single or multiple image based) evaluation is the absence of the haze-free image (ground-truth). This is also a problem when it concerns the validation of Koschmieder model or its subsequent dehazing methods. To overcome this problem, we created a database called CHIC (Color Hazy Image for Comparison), consisting of two scenes in controlled environment. In addition to the haze-free image, we provide 9 images of different fog densities. Moreover, for each scene, we provide a number of parameters such as local scene depth, distance from the camera of known objects such as Macbeth Color Checkers, their radiance, and the haze level through transmittance. All of these features allow the possibility to evaluate and compare between dehazing methods by using full-reference image quality metrics regarding the haze-free image, and also to evaluate the accuracy of the Koschmieder hazy image formation model

Facteurs de risque des actions ordinaires : le point de vue des gestionnaires québécois

L’objet de cet article est d’identifier les principaux facteurs que les gestionnaires professionnels de portefeuilles au Québec prennent en considération pour appréhender le risque de leur placement en actions ordinaires.The purpose of this paper is to identify the main factors professional fund managers in Québec take into consideration when assessing the riskiness of their investment in common stocks