De Cabanons en cabanes

Dans le Sud-Est de la France, le pastoralisme repose sur l’exploitation successive de différents pâturages qui permettent de disposer tout au long de l’année de ressources fourragères mangées sur pied par les troupeaux. Un tel système est fondé sur l’itinérance et le gardiennage quotidien des bêtes par un berger qui suit le troupeau dans ses déplacements annuels, dont l’ampleur est variable. La transhumance, par laquelle hommes et bêtes quittent, à la fin du printemps, la plaine pour les pâturages alpins, s’inscrit dans ce système d’économie fourragère qui caractérise de nombreuses cultures pastorales de Méditerranée et d’ailleurs. Cette organisation suppose une mobilité résidentielle que peu d’études questionnent et dont nous proposons une première approche à partir de l’élevage ovin transhumant de la Crau. On s’attache à décrire et analyser les différents habitats des bergers transhumants, du cabanon de Crau à la cabane d’alpage, dans un contexte de transformation forte du métier de berger. Celle-ci tient, d’une part, à l’évolution des caractéristiques sociologiques (féminisation, rajeunissement) d’une activité en voie de professionnalisation (formation et qualification accrue, légitimité environnementale). Elle tient d’autre part à l’installation du loup, depuis 1992, dans les territoires pastoraux alpins. Cet événement a considérablement bouleversé les fondements du pastoralisme qui s’était développé en l’absence de ce prédateur, dont le retour a très brutalement imposé une réorganisation des pratiques d’élevage en montagne. C’est dans ce contexte très particulier que nous examinons les formes et les modalités de la mobilité résidentielles des bergers tout au long de l’année, en nous focalisant particulièrement sur l’habitat en montagne. En effet, nous montrons en quoi la présence du loup rend encore plus décisive et stratégique la double fonction, résidentielle et pastorale, des cabanes d’alpage dont une version directement liée à la situation – les cabanes d’appoint ou cabanes « prédation » – commence à s’installer dans le paysage à des altitudes qui n’ont jamais connu la moindre construction.In the south eastern regions of France, pastoralism is based on the successive exploitation of different pastures allowing for all year round use of fodder resources through grazing. Such a system is founded on itinerancy by a shepherd who looks after the animals on a daily basis and follows them in their yearly changes of location, the scale of which is variable. The transhumance, during which men and animals leave the plains for alpine pastures at the end of spring, forms part of the fodder economy system, which characterises many pastoral cultures around the Mediterranean and elsewhere. Such an organisation implies the residential mobility of shepherds which few studies have so far questioned and which we propose to consider for the first time using the example of ovine transhumant breeding in the Crau. We focus on describing and analysing the various houses of transhumant shepherds, from the Crau hut [cabanon] to the cabin [cabane] in alpine pastures, set in the context of great changes to the shepherds’ occupation. These changes result on the one hand from the evolution of the sociological features (increase in women and in younger people) of an activity which is becoming a full professional occupation (training and increasing qualification, environmental legitimacy). On the other hand, they result from the return of wolves to the alpine pastures since 1992. This has considerably altered the foundations of pastoralism, which had developed in the absence of the predator, the return of which has very brutally imposed a reorganisation of breeding practices in the mountains. Our examination of the forms and conditions of shepherds’ yearly residential mobility is set against this particular context and focusses on mountain habitats. As we demonstrate, the wolf’s presence makes the double function, i.e. residential and pastoral, of alpine cabin even more crucial and strategic, in that a specific type of cabin especially adapted to these new circumstances - namely ‘auxiliary’ or ‘predation’ cabin - is starting to appear at altitudes where man-made structures had never before been seen

Kinetics of pore formation by the Bacillus thuringiensis toxin Cry1Ac

AbstractAfter binding to specific receptors, Cry toxins form pores in the midgut apical membrane of susceptible insects. The receptors could form part of the pore structure or simply catalyze pore formation and consequently be recycled. To discriminate between these possibilities, the kinetics of pore formation in brush border membrane vesicles isolated from Manduca sexta was studied with an osmotic swelling assay. Pore formation, as deduced from changes in membrane permeability induced by Cry1Ac during a 60-min incubation period, was strongly dose-dependent, but rapidly reached a maximum as toxin concentration was increased. Following exposure of the vesicles to the toxin, the osmotic swelling rate reached a maximum shortly after a delay period. Under these conditions, at relatively high toxin concentrations, the maximal osmotic swelling rate increased linearly with toxin concentration. When vesicles were incubated for a short time with the toxin and then rapidly cooled to prevent the formation of new pores before and during the osmotic swelling experiment, a plateau in the rate of pore formation was observed as toxin concentration was increased. Taken together, these results suggest that the receptors do not act as simple catalysts of pore formation, but remain associated with the pores once they are formed

Risk of herbicide mixtures as a key parameter to explain phytoplankton fluctuation in a great lake: the case of Lake Geneva, Switzerland

Mixture risk assessment predictions have rarely been confronted with biological changes observed in the environment. In this study, long-term monitoring of a European great lake, Lake Geneva, provides the opportunity to assess to what extent the predicted toxicity of herbicide mixtures explains the changes in the composition of the phytoplankton community next to other classical limnology parameters such as nutrients. To reach this goal, the gradient of the mixture toxicity of 14 herbicides regularly detected in the lake was calculated using concentration addition and response addition models. A temporal gradient of toxicity was observed which decreased from 2004 to 2009. Redundancy analysis and partial redundancy analysis showed that this gradient explains a significant portion of the variation in phytoplankton community composition with and without having removed the effect of all other co-variables. Moreover, species that are significantly influenced, positively or negatively, by the decrease of toxicity in the lake over time are highlighted. It can be concluded that the herbicide mixture toxicity is one of the key parameters to explain phytoplankton changes in Lake Genev

Redox-Active Dysprosium Single-Molecule Magnet: Spectro-Electrochemistry and Theoretical Investigations

International audienc

The Role of Immune Checkpoint Blockade in Uveal Melanoma

Uveal melanoma (UM) represents the most common intraocular malignancy in adults and accounts for about 5% of all melanomas. Primary disease can be effectively controlled by several local therapy options, but UM has a high potential for metastatic spread, especially to the liver. Despite its clinical and genetic heterogeneity, therapy of metastatic UM has largely been adopted from cutaneous melanoma (CM) with discouraging results until now. The introduction of antibodies targeting CTLA-4 and PD-1 for immune checkpoint blockade (ICB) has revolutionized the field of cancer therapy and has achieved pioneering results in metastatic CM. Thus, expectations were high that patients with metastatic UM would also benefit from these new therapy options. This review provides a comprehensive and up-to-date overview on the role of ICB in UM. We give a summary of UM biology, its clinical features, and how it differs from CM. The results of several studies that have been investigating ICB in metastatic UM are presented. We discuss possible reasons for the lack of efficacy of ICB in UM compared to CM, highlight the pitfalls of ICB in this cancer entity, and explain why other immune-modulating therapies could still be an option for future UM therapies

Recommended β-lactam regimens are inadequate in septic patients treated with continuous renal replacement therapy

Introduction: Sepsis is responsible for important alterations in the pharmacokinetics of antibiotics. Continuous renal replacement therapy (CRRT), which is commonly used in septic patients, may further contribute to pharmacokinetic changes. Current recommendations for antibiotic doses during CRRT combine data obtained from heterogeneous patient populations in which different CRRT devices and techniques have been used. We studied whether these recommendations met optimal pharmacokinetic criteria for broad-spectrum antibiotic levels in septic shock patients undergoing CRRT.Methods: This open, prospective study enrolled consecutive patients treated with CRRT and receiving either meropenem (MEM), piperacillin-tazobactam (TZP), cefepime (FEP) or ceftazidime (CAZ). Serum concentrations of these antibiotics were determined by high-performance liquid chromatography from samples taken before (t = 0) and 1, 2, 5, and 6 or 12 hours (depending on the β-lactam regimen) after the administration of each antibiotic. Series of measurements were separated into those taken during the early phase ( 48 hours).Results: A total of 69 series of serum samples were obtained in 53 patients (MEM, n = 17; TZP, n = 16; FEP, n = 8; CAZ, n = 12). Serum concentrations remained above four times the minimal inhibitory concentration for Pseudomonas spp. for the recommended time in 81% of patients treated with MEM, in 71% with TZP, in 53% with CAZ and in 0% with FEP. Accumulation after 48 hours of treatment was significant only for MEM.Conclusions: In septic patients receiving CRRT, recommended doses of β-lactams for Pseudomonas aeruginosa are adequate for MEM but not for TZP, FEP and CAZ; for these latter drugs, higher doses and/or extended infusions should be used to optimise serum concentrations. © 2011 Seyler et al. licensee BioMed Central Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Differential retention of transposable element-derived sequences in outcrossing Arabidopsis genomes

International audienceBackground: Transposable elements (TEs) are genomic parasites with major impacts on host genome architecture and host adaptation. A proper evaluation of their evolutionary significance has been hampered by the paucity of short scale phylogenetic comparisons between closely related species. Here, we characterized the dynamics of TE accumulation at the micro-evolutionary scale by comparing two closely related plant species, Arabidopsis lyrata and A. halleri. Results: Joint genome annotation in these two outcrossing species confirmed that both contain two distinct populations of TEs with either 'recent' or 'old' insertion histories. Identification of rare segregating insertions suggests that diverse TE families contribute to the ongoing dynamics of TE accumulation in the two species. Orthologous TE fragments (i.e. those that have been maintained in both species), tend to be located closer to genes than those that are retained in one species only. Compared to non-orthologous TE insertions, those that are orthologous tend to produce fewer short interfering RNAs, are less heavily methylated when found within or adjacent to genes and these tend to have lower expression levels. These findings suggest that long-term retention of TE insertions reflects their frequent acquisition of adaptive roles and/or the deleterious effects of removing nearly neutral TE insertions when they are close to genes. Conclusion: Our results indicate a rapid evolutionary dynamics of the TE landscape in these two outcrossing species, with an important input of a diverse set of new insertions with variable propensity to resist deletion