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.

Morphological and functional characterisation of the burrow systems of six earthworm species (Lumbricidae)

Abstract: Earthworm burrow systems are generally described based on postulated behaviours associated with the three eco- logical types. In this study, we used X-ray tomography to obtain 3D information on the burrowing behaviour of six very common anecic (Aporrectodea nocturna and Lumbricus terrestris) and endogeic (Aporrectodea rosea, Allolobophora chlorotica, Aporrectodea caliginosa, Aporrectodea icterica) earthworm species, introduced into repacked soil cores for 6 weeks. A simple water infiltration test, the Beerkan method, was also used to assess some functional properties of these burrow systems. Endogeic worms make larger burrow sys- tems, which are more highly branched, less continuous and of smaller diameter, than those of anecic worms. Among the anecic species, L. terrestris burrow systems are shorter (9.2 vs 21.2 m) with a higher number (14.5 vs 23.5) of less branched burrows (12.2 vs 20.2 branches m �1 ), which are also wider (7.78 vs 5.16 mm) than those of A. nocturna .I n comparison, the burrow systems made by endogeic species appeared sim- ilar to each other. However, A. rosea burrows were short and narrow, whereas A. icterica had a longer burrow system (15.7 m), more intense bioturbation intensity (refilled macropores or soil lateral compaction around them) and thus a greater number of burrows. Regarding water infiltration, anecic burrow systems were far more efficient due to open burrows linking the top and bottom of the cores. For endogeic species, we observed a linear relationship between burrow length and the water infiltration rate (R 2 =0.49, p<0.01). Overall, the three main characteristics significantly influenc- ing water infiltration were burrow length, burrow number and bioturbation volume. This last characteristic highlighted the effect of burrow refilling by casts.

Tight LP bounds for resource constrained project scheduling

Abstract: The best lower bound for the Resource Constrained Project Scheduling Problem is currently based on the resolution of several large Linear Programs (Brucker & Knust, EJOR, 107: 272-288, 1998). In this paper, we show that (1) intensive constraint propagation can be used to tighten the initial formulation of the linear programs and (2) we introduce several sets of valid cutting planes. These improvements allow us to “close” 16 new instances of the PSPLIB with 60 activities and to improve the best known lower bounds of 64 instances.

Social and Hydrological Responses to Extreme Precipitations: An Interdisciplinary Strategy for Postflood Investigation

Abstract: This paper describes and illustrates a methodology to conduct postflood investigations based on interdisciplinary collaboration between social and physical scientists. The method, designed to explore the link between crisis behavioral response and hydrometeorological dynamics, aims at understanding the spatial and temporal capacities and constraints on human behaviors in fast-evolving hydrometeorological conditions. It builds on methods coming from both geosciences and transportations studies to complement existing post-flood field investigation methodology used by hydrometeorologists. The authors propose an interview framework, structured around a chronological guideline to allow people who experienced the flood firsthand to tell the stories of the circumstances in which their activities were affected during the flash flood. This paper applies the data collection method to the case of the 15 June 2010 flash flood event that killed 26 people in the Draguignan area (Var, France). As a first step, based on the collected narratives, an abductive approach allowed the identification of the possible factors influencing individual responses to flash floods. As a second step, behavioral responses were classified into categories of activities based on the respondents' narratives. Then, aspatial and temporal analysis of the sequences made of the categories of action to contextualize the set of coping responses with respect to local hydrometeorological conditions is proposed. During this event, the respondents mostly follow the pace of change in their local environmental conditions as the flash flood occurs, official flood anticipation being rather limited and based on a large-scale weather watch. Therefore, contextual factors appear as strongly influencing the individual's ability to cope with the event in such a situation.