Earthworm community characteristics during afforestation of abandoned chalk grasslands (Upper Normandy, France)

La biomasse, la densité et la composition spécifique des vers de terre a été évaluée dans différents stades d'une succession secondaire après l'abandon d'une pelouse calcicole pâturée. La biomasse et la densité des populations de vers de terre sont très élevées (51,2 à 130,2 g/m2 et 175,8 à 522,6 ind/m2 en moyenne) dans toutes les parcelles échantillonnées. L'abandon du pâturage conduit à un rapide développement des communautés de vers. La biomase et la densité atteignent leur maximum dans une pelouse récemment mise en exclos, puis diminue dans une pelouse abandonnée depuis 50 ans. La densité croit ensuite, alors que la biomasse diminue légèrement pendant l'installation du bois de feuillus. La densité et la biomasse sont minimales sous pinède. La richesse taxonomique (nombre d'unités taxonomiques) ne change pas pendant la succession, mais la composition spécifique varie de façon nette. La dynamique des communautés de vers de terre semblent être sous l'influence de deux facteurs environnementaux prépondérants, eux-même étroitement liés à deux paramètres de la végétation : la structure verticale de la végétation (importance de la couverture du sol par la végétation herbacée, la litière, les mousses, présence d'arbres) et la qualité des litières restituées, liées à la nature de la végétation (herbacée, conifères ou feuillus). (Résumé d'auteur

Dynamic Formation of Metastable Intermediate State Patterns in Type-I Superconductors

Structure of the intermediate state in type-I superconducting lead (Pb) is shown to be very sensitive to the ramp rate of an applied magnetic field. The configurations of resulting static patterns depend sensitively on the shape of the specimen. In particular, geometric barrier, present in the samples with rectangular cross-section, plays an important role in determining the sharp boundary between the phases of different topology. We propose that seemingly laminar (stripe) pattern obtained as a result of the fast field ramp is simply an imprint left behind by the fast-moving flux tubes. Our results confirm that flux tube phase is topologically favorable.Comment: to be presented at LT-25 (Amsterdam, 2008

Factors influencing soil macrofaunal communities in post-pastoral successions of western France

The soil macrofaunal communities (Lumbricidae, Formicidae, Coleoptera, Chilopoda, Diplopoda, Isopoda, Arachnida, Gastropoda) were studied in six plots representing different stages in theoretical post-pastoral succession chalk grassland. Macrofaunal biomass was high in all the plots (70.2-140.3 g/m2). The macroinvertebrate communities along successional gradients respond to two major environmental factors : the structure of the vegetation, which determines the diversity of microhabitats and life conditions for macroinvertebrates ; and the quality of above-ground litter production, which depends on the nature of vegetation and the presence of domestic herbivores. (Résumé d'auteur

Parametrised Preisach Modelling of Hysteresis in High Temperature Superconductors

We present a parametrised Preisach-type model that describes the hysteresis exhibited by the high temperature superconductors (HTSC); hysteresis is the main cause for losses in the subcritical domain. The parametrised model, in combination with electrical measurements, is independent of geometry, number of filaments and other physical measures, and is identified by a novel method that uses electrical lock-in (loss) measurement technique, which greatly enhances the signal to noise ratio. Identification results from measurements on Bi-2223 multi-filamentary tapes are presented. We have further derived exact models for the hysteretic losses in strip and elliptic geometry strips, where the energy losses were calculated by Norris. The paper contains analysis of the Preisach Model, of its losses and of the suggested parametrisation

MRI in multiple myeloma : a pictorial review of diagnostic and post-treatment findings

Magnetic resonance imaging (MRI) is increasingly being used in the diagnostic work-up of patients with multiple myeloma. Since 2014, MRI findings are included in the new diagnostic criteria proposed by the International Myeloma Working Group. Patients with smouldering myeloma presenting with more than one unequivocal focal lesion in the bone marrow on MRI are considered having symptomatic myeloma requiring treatment, regardless of the presence of lytic bone lesions. However, bone marrow evaluation with MRI offers more than only morphological information regarding the detection of focal lesions in patients with MM. The overall performance of MRI is enhanced by applying dynamic contrast-enhanced MRI and diffusion weighted imaging sequences, providing additional functional information on bone marrow vascularization and cellularity. This pictorial review provides an overview of the most important imaging findings in patients with monoclonal gammopathy of undetermined significance, smouldering myeloma and multiple myeloma, by performing a 'total' MRI investigation with implications for the diagnosis, staging and response assessment. Main message aEuro cent Conventional MRI diagnoses multiple myeloma by assessing the infiltration pattern. aEuro cent Dynamic contrast-enhanced MRI diagnoses multiple myeloma by assessing vascularization and perfusion. aEuro cent Diffusion weighted imaging evaluates bone marrow composition and cellularity in multiple myeloma. aEuro cent Combined morphological and functional MRI provides optimal bone marrow assessment for staging. aEuro cent Combined morphological and functional MRI is of considerable value in treatment follow-up

How a haemosporidian parasite of bats gets around: the genetic structure of a parasite, vector and host compared.

Parasite population structure is often thought to be largely shaped by that of its host. In the case of a parasite with a complex life cycle, two host species, each with their own patterns of demography and migration, spread the parasite. However, the population structure of the parasite is predicted to resemble only that of the most vagile host species. In this study, we tested this prediction in the context of a vector-transmitted parasite. We sampled the haemosporidian parasite Polychromophilus melanipherus across its European range, together with its bat fly vector Nycteribia schmidlii and its host, the bent-winged bat Miniopterus schreibersii. Based on microsatellite analyses, the wingless vector, and not the bat host, was identified as the least structured population and should therefore be considered the most vagile host. Genetic distance matrices were compared for all three species based on a mitochondrial DNA fragment. Both host and vector populations followed an isolation-by-distance pattern across the Mediterranean, but not the parasite. Mantel tests found no correlation between the parasite and either the host or vector populations. We therefore found no support for our hypothesis; the parasite population structure matched neither vector nor host. Instead, we propose a model where the parasite's gene flow is represented by the added effects of host and vector dispersal patterns

Serological proteome analysis reveals new specific biases in the IgM and IgG autoantibody repertoires in autoimmune polyendocrine syndrome type 1

Objective: Autoimmune polyendocrine syndrome type 1 (APS 1) is caused by mutations in the AIRE gene that induce intrathymic T-cell tolerance breakdown, which results in tissue-specific autoimmune diseases. Design: To evaluate the effect of a well-defined T-cell repertoire impairment on humoral self-reactive fingerprints, comparative serum self-IgG and self-IgM reactivities were analyzed using both one- and two-dimensional western blotting approaches against a broad spectrum of peripheral tissue antigens. Methods: Autoantibody patterns of APS 1 patients were compared with those of subjects affected by other autoimmune endocrinopathies (OAE) and healthy controls. Results: Using a Chi-square test, significant changes in the Ab repertoire were found when intergroup patterns were compared. A singular distortion of both serum self-IgG and self-IgM repertoires was noted in APS 1 patients. The molecular characterization of these antigenic targets was conducted using a proteomic approach. In this context, autoantibodies recognized more significantly either tissue-specific antigens, such as pancreatic amylase, pancreatic triacylglycerol lipase and pancreatic regenerating protein 1α, or widely distributed antigens, such as peroxiredoxin-2, heat shock cognate 71-kDa protein and aldose reductase. As expected, a well-defined self-reactive T-cell repertoire impairment, as described in APS 1 patients, affected the tissue-specific self-IgG repertoire. Interestingly, discriminant IgM reactivities targeting both tissue-specific and more widely expressed antigens were also specifically observed in APS 1 patients. Using recombinant targets, we observed that post translational modifications of these specific antigens impacted upon their recognition. Conclusions: The data suggest that T-cell-dependent but also T-cell-independent mechanisms are involved in the dynamic evolution of autoimmunity in APS 1

Classification d'expressions vocales passives versus actives

Six expressions sont généralement considérées pour caractériser les états émotifs humains : Sourire, Surprise, Colère, Tristesse, dégoût et Neutre. Différentes mesures peuvent être extraites à partir du signal de parole pour caractériser ces expressions, à savoir la fréquence fondamentale, l'énergie, le SPI (rapport des énergies des HF et des BF dans le signal) et le débit de parole. Une classification automatique des cinq expressions basées sur ces caractéristiques présente des conflits entre la Colère, la Surprise et le Sourire d'une part et le Neutre et la Tristesse d'autre part. Ce conflit entre classes d'expressions est également retrouvé chez le classifieur humain. Nous proposons donc de définir deux classes d'expressions: Active regroupant le Sourire, la Surprise et la Colère et Passive regroupant le Neutre et la Tristesse. Une telle classification est également plus réaliste et plus appropriée pour l'intégration d'information de parole dans un système de classification multimodale combinant la parole et la vidéo, ce qui est à long terme le but de notre travail. Dans ce papier, différentes méthodes de classification sont testées: un classifieur Bayésien, une Analyse Discriminante Linéaire (ADL), le classifieur au K plus proches vosins(KNN) et un classifieur à Machine à Vecteur de Support (SVM) avec une fonction de base gaussienne. Pour les deux classes considérées, les meilleurs taux de classification sont obtenus avec le classificateur SVM avec un taux de reconnaissance de 89.74% pour l'état Actif et de 86.54 % pour l'état Passif