Productivité du travail et "Labour Hoarding"

Cet exposé s'attarde à expliquer les mouvements dans la productivité du travail. Le but de cet ouvrage est de tester les résultats théoriques de Horning (1994). Celui-ci propose des mouvements procycliques du "labour hoarding" comme solution aux problèmes encourus par les modèles des cycles réels. Comme il est démontré ici, cette corrélation positive entre le "labour hoarding" et le cycle économique fait en sorte que la productivité est plus volatile que les statistiques habituelles peuvent laisser croire. This paper try to explain labour productivity fluctuations. We test empirically the proposition made by Horning (1994) that procyclical movements in labour hoarding can explained the puzzle raised by the apparent low volatility of labour productivity. This is because with a positive correlation between labour hoarding and the business cycle, the productivity is more volatile than the empirical facts habitually show.Labour hoarding, productivité du travail, demande de travail, élasticités de demande de travail de court terme, élasticité de demande de travail de long terme, procyclicité de la productivité, volatilité de la productivité

Initial results from a hydroacoustic network to monitor submarine lava flows near Mayotte Island

In 2019, a new underwater volcano was discovered at 3500 m below sea level (b.s.l.), 50 km east of Mayotte Island in the northern part of the Mozambique Channel. In January 2021, the submarine eruption was still going on and the volcanic activity, along with the intense seismicity that accompanies this crisis, was monitored by the recently created REVOSIMA (MAyotte VOlcano and Seismic Monitoring) network. In this framework, four hydrophones were moored in the SOFAR channel in October 2020. Surrounding the volcano, they monitor sounds generated by the volcanic activity and the lava flows. The first year of hydroacoustic data evidenced many earthquakes, underwater landslides, large marine mammal calls, along with anthropogenic noise. Of particular interest are impulsive signals that we relate to steam bursts during lava flow emplacement. A preliminary analysis of these impulsive signals (ten days in a year, and only one day in full detail) reveals that lava emplacement was active when our monitoring started, but faded out during the first year of the experiment. A systematic and robust detection of these specific signals would hence contribute to monitor active submarine eruptions in the absence of seafloor deep-tow imaging or swath-bathymetry surveys of the active area

Effets de la corticothérapie au long cours sur les anastomoses colorectales

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Three new Plant Associations in the Middle-european Forests of France: Deschampsio cespitosae-Fagetum sylvaticae, Sorbo ariae-Quercetum petraeae and Carici brizoidis-Fraxinetum excelsioris

This article proposes the validation of 3 plant associations described or referred to by Rameau and in several national and regional synopses (Rameau, 1996 and 1997; Rameau et al., 2000; Bensettiti et al., 2001; Royer et al., 2006). Deschampsio cespitosae-Fagetum sylvaticae (Rameau 1996) Renaux, Boeuf and Royer ass. nov. is very common on the silt deposits in north-eastern France. It corresponds to the Poo chaixii-Fagetum sylvaticae Rameau 1996 nom. inval., a well-known but so far not validly published syntaxon. It is the central association for Carpino betuli-Fagion sylvaticae Boeuf and Renaux in Boeuf (2010) also proposed in this issue. Sorbo ariae-Quercetum petraeae Rameau (1974, 1996) Renaux, Royer and Boeuf ass. nov. is connected with calcareous hills and is principally characterized by climate (the dry climate of the hills of Burgundy and adjacent areas). This poorly known association belongs to the Carpinion betuli Issler 1931 alliance. As for the third, named Carici brizoidis-Fraxinetum excelsioris (Oberdorfer 1957) Renaux, Boeuf and Royer ass. nov., it is characterised by pedunculate oak stands on hydromorphic silts classified in Fraxino excelsioris-Quercion roboris Pass. et Hofm. 1968. In addition to being based on bibliographical data bases, our results are supported by the use of 9 760 relevés distributed throughout France and rely on a fidelity index that documents the choice of the combination of characteristic species.La validation de 3 associations végétales décrites ou citées par Rameau et dans plusieurs synthèses nationales et régionales (Rameau, 1996 et 1997 ; Rameau et al., 2000 ; Bensettiti et al., 2001 ; Royer et al., 2006) est ici proposée. Très répandu sur les placages limoneux du Nord-Est de la France, le Deschampsio cespitosae- Fagetum sylvaticae (Rameau 1996) Renaux, Boeuf et Royer ass. nov. correspond au Poo chaixii-Fagetum sylvaticae Rameau 1996 nom. inval., syntaxon bien connu mais encore non publié de façon valide à ce jour. C’est l’association centrale du Carpino betuli-Fagion sylvaticae Boeuf et Renaux in Boeuf (2010) proposé dans ce même numéro. Le Sorbo ariae-Quercetum petraeae Rameau (1974, 1996) Renaux, Royer et Boeuf ass. nov. est lié aux côtes calcaires avec un déterminisme principal de nature climatique (climat sec des côtes de Bourgogne et régions voisines). Cette association relevant du Carpinion betuli Issler 1931 était méconnue. Quant à la troisième désignée comme Carici brizoidis-Fraxinetum excelsioris (Oberdorfer 1957) Renaux, Boeuf et Royer ass. nov., elle caractérise des chênaies pédonculées sur limons hydromorphes classées dans le Fraxino excelsioris- Quercion roboris Pass. et Hofm. 1968. En plus des bases bibliographiques, nos résultats s’appuient sur l’utilisation de 9 760 relevés répartis à travers la France ainsi que l’utilisation d’un indice de fidélité permettant notamment d’objectiver le choix de la combinaison d’espèces caractéristiques

A global decentralized control strategy for urban vehicle platooning using monocular vision and laser rangefinder

International audienceTo address traffic saturation in cities, new “Urban Transportation Systems”, based on electric vehicles in freeaccess, are in developing. One necessary functionality of such systems is their ability to move in a platoon fashion. A global decentralized platoon control strategy, supported by inter-vehicle communications, is addressed in this paper, relying on nonlinear control techniques. The main interest in a global approach is that servoing error accumulation can be avoided, whatever the platoon length. However, absolute vehicle localization is then required. In urban applications, cameras are realistic sensors, but localization is supplied in a 3D visual virtual world, slightly distorted w.r.t. the actual metric one. To enable accurate guidance, local corrections to the visual world are here computed from the data supplied by a laser rangefinder mounted on the second vehicle, and then shared with the whole platoon. Full-scale experiments demonstrate the performance of the proposed approach

Seasonal demography of different black rat (Rattus rattus) populations under contrasting natural habitats in Guadeloupe (Lesser Antilles, Caribbean).

12 pagesInternational audienceThe black rat (Rattus rattus) is one of the most widespread rodents on islands worldwide, introduced over the last five centuries. However, reliable information concerning how biotic or abiotic factors influence key parameters of black rat population biology in insular contexts is currently unavailable. Here we aim to document the relative abundance of rat populations and evaluate how the age structure and the body mass of adult individual vary seasonally in different forest environments under contrasting climatic conditions. Rats were captured during wet and dry seasons in 2017–2018 at one or two sites in each of the four natural forested environments of Guadeloupe, all of which experience widely different annual rainfall (semi-deciduous dry forest, seasonal evergreen forest, mountain rainforest and Pterocarpus officinalis swamp forest). A total of 171 black rats were captured during a 1018 trap-night effort. Overall capture results confirm this species to thrive in all the natural forested environments we investigated. With the exception of the P. officinalis swamp forest, black rat populations reach higher relative abundances during the wet season due to juvenile and sub-adult recruitment at the end of the dry season. In contrast, in the P. officinalis swamp forest, breeding activity continues during both seasons and relative rat abundance appears to fluctuate less seasonally. The relative abundance of adult black rats is also higher in the seasonal semi-evergreen and rainforests that experience little or no water stress. These contexts therefore appear the most favourable for sustaining black rat populations, a pattern that is most likely connected to a combination of climatic and/or edaphic parameters that condition the year-round availability and abundance of food resources

Effects of the Mediterranean Diet before and after Weight Loss on Eating Behavioral Traits in Men with Metabolic Syndrome

The objective of this study was to investigate the impact of the Mediterranean diet (MedDiet) consumed before and after weight loss on eating behavioral traits as measured by the Three-Factor Eating Questionnaire (TFEQ) in men with metabolic syndrome (MetS). In this fixed sequence study, 19 men with MetS (National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) criteria), aged between 24 and 62 years, first consumed a five-week standardized North American control diet followed by a five-week MedDiet, both under weight-maintaining controlled-feeding conditions. This was followed by a 20-week caloric restriction weight loss period in free-living conditions, without specific recommendations towards adhering to the principles of the MedDiet. Participants were finally subjected to a final five-week MedDiet phase under isoenergetic controlled-feeding conditions. The MedDiet before weight loss had no impact on eating behavioral traits. Body weight reduction by caloric restriction (−10.2% of initial weight) was associated with increased cognitive restraint (p < 0.0001) and with reduced disinhibition (p = 0.02) and susceptibility to hunger (p = 0.01). Feeding the MedDiet for five weeks under isoenergetic conditions after the weight loss phase had no further impact on eating behavioral traits. Results of this controlled-feeding study suggest that consumption of the MedDiet per se has no effect on eating behavioral traits as measured by TFEQ, unless it is combined with significant weight loss