How to Handle Concomitant Asymptomatic Prosthetic Joints During an Episode of Hematogenous Periprosthetic Joint Infection:a Multicenter Analysis

BACKGROUND: Prosthetic joints are at risk of becoming infected during an episode of bacteremia, especially during Staphylocococcus aureus bacteremia. However, it is unclear how often asymptomatic periprosthetic joint infection (PJI) occurs, and whether additional diagnostics should be considered. METHODS: In this multicenter study, we retrospectively analyzed a cohort of patients with a late acute (hematogenous) PJI between 2005-2015 who had concomitant prosthetic joints in situ. Patients without at least 1 year of follow-up were excluded. RESULTS: We included 91 patients with a hematogenous PJI and 108 concomitant prosthetic joints. The incident PJI was most frequently caused by Staphylococcus aureus (43%), followed by streptococci (26%) and Gram-negative rods (18%). Of 108 concomitant prosthetic joints, 13 were symptomatic, of which 10 were subsequently diagnosed as a second PJI. Of the 95 asymptomatic prosthetic joints, 1 PJI developed during the follow-up period and was classified as a "missed" PJI at the time of bacteremia with S. aureus (1.1%). Infected prosthetic joints were younger than the noninfected ones in 67% of cases, and prosthetic knees were affected more often than prosthetic hips (78%). CONCLUSIONS: During an episode of hematogenous PJI, concomitant asymptomatic prosthetic joints have a very low risk of being infected, and additional diagnostic work-up for these joints is not necessary

Combining farmers' decision rules and landscape stochastic regularities for landscape modelling

International audienceLandscape spatial organization (LSO) strongly impacts many environmental issues. Modelling agricultural landscapes and describing meaningful landscape patterns are thus regarded as key-issues for designing sustainable landscapes. Agricultural landscapes are mostly designed by farmers. Their decisions dealing with crop choices and crop allocation to land can be generic and result in landscape regularities, which determine LSO. This paper comes within the emerging discipline called "landscape agronomy", aiming at studying the organization of farming practices at the landscape scale. We here aim at articulating the farm and the landscape scales for landscape modelling. To do so, we develop an original approach consisting in the combination of two methods used separately so far: the identification of explicit farmer decision rules through on-farm surveys methods and the identification of landscape stochastic regularities through data-mining. We applied this approach to the Niort plain landscape in France. Results show that generic farmer decision rules dealing with sunflower or maize area and location within landscapes are consistent with spatiotemporal regularities identified at the landscape scale. It results in a segmentation of the landscape, based on both its spatial and temporal organization and partly explained by generic farmer decision rules. This consistency between results points out that the two modelling methods aid one another for land-use modelling at landscape scale and for understanding the driving forces of its spatial organization. Despite some remaining challenges, our study in landscape agronomy accounts for both spatial and temporal dimensions of crop allocation: it allows the drawing of new spatial patterns coherent with land-use dynamics at the landscape scale, which improves the links to the scale of ecological processes and therefore contributes to landscape ecology.L'organisation du paysage influe sur les problèmes environnementaux. Modéliser les paysages pour les décrire à l'aide de formes significatives est une étage clé. Les paysages agricoles sont principalement construits par les agriculteurs dont les décision d'assolement peuvent être génériques et déterminer des régularités dans l'organisation du paysage. Cet article contribue à l'agronomie des paysage qui est une discipline émergente. Nous cherchons à articuler les échelles du paysage et de l'exploitation agricole en développant deux méthodes : l'une consiste à identifier les décisions des agriculteurs par le bais d'enquêtes, l'autre consiste à retrouver des régularités stochastiques dans le paysage par le bais de fouille de données. Nous avons appliqué cette approche au paysage de la plaine de Niort en France. Les résultats montrent que les décisions des agriculteurs en matière de tournesol et maïs sont génériques et ont des effets sur le paysages que des méthodes de fouille de données révèlent et quantifient

Réflexion sur l'évolution contemporaine des exploitations agricoles

[fre] Après avoir précisé les grands traits du fonctionnement des trois systèmes constitutifs de l'exploitation agricole (écosystème cultivé, système de production, famille), et insisté sur le rôle déterminant de la famille et de la durée attendue de la relation familile-exploitation, les auteurs montrent quels points ont pu être modifiés du fait de l'évolution contemporaine des techniques. Analysant les difficultés de l'adoption d'une innovation technique (les propositions techniques sont sectorielles, peuvent rendre le système plus fragile, ne sont pas toujours compatibles avec les choix faits dans le passé et l'histoire de 'l'agriculteur), ils montrent qu'il existe trois trajectoires principales d'évolution différenciant des types d'exploitations, dont certains seulement ont des résultats technico-économiques élevés. Ils soulignent également que les évolutions techniques, elles-mêmes induites par les évolutions socio-économiques, font apparaître des points de blocage nouveaux, et évoquent en conclusion la perspective future de stabilisation des systèmes de production autour de modèles améliorant plutôt la qualité de vie des agriculteurs que les performances techniques. [eng] Thoughts on certain aspects of the present-day evolution farms - The authors of this paper first define the main lines of the way the three systems that make up farming (cultivated ecosystem, production system, family) function and insist on the fundamental role of the family and of the expected duration of the family-farm relationship, and then show what aspects may have been modified by modern development in techniques. They analyse the difficulty in adopting any form of technical innovation (technical proposals are by sector, may make the , system more fragile, are not always compatible with choices made in the past and with the farmer's past life) and show that farms may develop in three main ways and that not all of them have high technical and economic results. They also underline the fact that technical improvements, that result from socio-economic changes, show up new blockages and in conclusion refer to the future outlook for the stabilization of production systems around models that improve the farmers' life style rather than technical performances.