University of Avignon

About: University of Avignon is a education organization based out in Avignon, Provence-Alpes-Côte-d'Azur, France. It is known for research contribution in the topics: Population & Speaker recognition. The organization has 1526 authors who have published 3766 publications receiving 88928 citations.

From Laboratory to Industry: Scale-Up, Quality, and Safety Consideration for Microwave-Assisted Extraction

Abstract: The application of microwave technologies has been scaled up in the food and cosmetic industries because of its economic and environmental advantages, which have been increasingly proved by plentiful laboratory-scale successes. However, this kind of emerging technology often causes hazards for product safety and risks in manual operation. Because conventional quality control methods are insufficient to control these hazards and risks, Hazard Analysis Critical Control Points (HACCP) and Hazard and Operability (HAZOP) study, which are considered effective analyses of respective controlling potential hazards and operator security, must be taken into account in the design of microwave application in production processing chain.

Secure Clustering Scheme Based Keys Management in VANETs

Abstract: We propose an efficient dynamic architecture of the Public Key infrastructure (PKI) for vehicular ad hoc networks (VANETs) based on a trust model and a novel distributed clustering algorithm. Furthermore, we introduce the notion of a VANET Dynamic Demilitarized Zone (VDDZ), composed of the set of confident vehicles located within the immediate neighborhood of each clusterhead (CH) to assume the Registration Authorities (RA). The VDDZ aims to secure the elected CAs by shielding them from unknown or malicious vehicles. A host of simulations using urban and highway scenarios are conducted to investigate the effects of the transmission range, the speed of vehicles and the number of confident vehicles in the network on the security level, the stability and the efficiency of our proposed architecture. In particular, the results show a strong dependency of the security and the stability on the assumed percentage of trust nodes and the mobility models.

Assessing the Potentialities of FORMOSAT-2 Data for Water and Crop Monitoring at Small Regional Scale in South-Eastern France

Abstract: Water monitoring at the scale of a small agricultural region is a key point to insure a good crop development particularly in South-Eastern France, where extreme climatic conditions result in long dry periods in spring and summer with very sparse precipitation events, corresponding to a crucial period of crop development. Remote sensing with the increasing imagery resolution is a useful tool to provide information on plant water status over various temporal and spatial scales. The current study focussed on assessing the potentialities of FORMOSAT-2 data, characterized by high spatial (8m pixel) and temporal resolutions (1-3 day/time revisit), to improve crop modeling and spatial estimation of the main land properties. Thirty cloud free images were acquired from March to October 2006 over a small region called Crau-Camargue in SE France, while numerous ground measurements were performed simultaneously over various crop types. We have compared two models simulating energy transfers between soil, vegetation and atmosphere: SEBAL and PBLs. Maps of evapotranspiration were analyzed according to the agricultural practices at field scale. These practices were well identified from FORMOSAT-2 images, which provided accurate input surface parameters to the SVAT models.

A Robust Method for Assessing 3-D Topographic Site Effects: A Case Study at the LSBB Underground Laboratory, France

Abstract: By means of three-dimensional (3-D) numerical simulations, including the Laboratoire Souterrain a Bas-Bruit (LSBB) topography, we carefully analyze site effects assessments yielded by two approache...

Metabolism in orange fruits is driven by photooxidative stress in the leaves.

Abstract: In plants, stress signals propagate to trigger distant responses and thus stress acclimation in non-exposed organs. We tested here the hypothesis that leaves submitted to photooxidative stress may influence the metabolism of nearby fruits and thus quality criteria. Leaves of orange trees (Citrus sinensis (L.) Osbeck cv. 'Navelate') were acclimated to shade for 1 week and then submitted to full (FL) and medium light (ML) conditions. As expected, photoin-hibition was detected in leaves of both FL and ML treatments as revealed by stress indicators (F v /F m , Performance Index) for at least 99 h after treatments. In the fruits near the stressed leaves, we then determined the activities of enzymes related to oxidative stress, superoxide dismutase, catalase and the enzymes of the ascorbate (AA)/glutathione cycle, as well as the contents in sugars, organic acids and carotenoids. Ascorbate peroxidase and monode-hydroascorbate reductase activities in the pulp of fruits were dramatically higher in both treatments when compared to the control. AA and total sugars were not affected by the photooxidative stress. However, the FL treatment resulted in a 16% increase in total organic acids, with succinic acid being the major contributor, a shift towards less glucose + fructose and more sucrose, and a 15% increase in total carotenoids, with cis-violaxanthin being the major contributor. Our observations strongly suggest the existence of a signal generated in leaves in consequence of photooxidative stress, transmitted to nearby fruits. Exploiting such a signal by agronomic means promises exciting perspectives in managing quality criteria in fruits accumulating carotenoids.