Photoproduction of Pion Pairs in Hydrogen

The photoproduction of pion pairs has been observed by detecting, in a magnetic spectrometer, the negative pions which emerged at 60° and at 120° from a hydrogen target in the bremsstrahlung beam of an electron synchrotron. The yields of negative pions "per equivalent quantum" were measured for several values of the pion energy and the bremsstrahlung cutoff energy. From the variations of the yields with bremsstrahlung cutoff energy, the cross section for the emission of negative pions was obtained. The cross section shows no large dependence on the pion angle from 90° to 150° in the c.m. system. The integral of the cross section over the negative pion energy is consistent with a constant value of about 4×10^-30 cm^2/sterad for photon energies between 600 and 1100 Mev. The observed dependence of the cross section on pion energy has been compared to some phenomenological models

Les associations sanitaires et sociales: quels enjeux actuels?

International audienceCe chapitre introductif de la deuxième partie de l'ouvrage collectif, sous la direction de Robert Lafore, s’attachera à retracer les évolutions récentes des associations en général et plus particulièrement à celles du secteur médico-social et social : croissance ralentie, privatisation rampante de leurs ressources, besoin de réparation sociale croissants et évolution démographiques ambigües. Puis on verra les principaux enjeux auxquels les associations auront à faire face : banalisation ou innovation perpétuelle, ressources humaines plus difficiles à gérer, partenariat avec les pouvoirs publics à reconstruire sur de nouvelles bases. Enfin les chapitres suivants sont introduits

Exciton photon strong-coupling regime for a single quantum dot in a microcavity

We report on the observation of the strong coupling regime between a single GaAs quantum dot and a microdisk optical mode. Photoluminescence is performed at various temperatures to tune the quantum dot exciton with respect to the optical mode. At resonance, we observe an anticrossing, signature of the strong coupling regime with a well resolved doublet. The Vacuum Rabi splitting amounts to 400 μeV and is twice as large as the individual linewidths.Comment: submitted on November 7th 200

Information Systems Evolution: A Process Model for Integrating New Services

Integration of different components that compose enterprise Information System (IS) represents a big challenge in the IS development. However, it is indispensable in order to avoid fragmentation of the IS and redundancy between different IS applications. In this work we consider service-driven IS engineering as a prospective approach to deal with IS fragmentation and interoperability of different IS components. We introduce the notion of Information System Service (ISS) and propose a process model supporting legacy IS evolution by integration of new services. We claim that such an approach has to take into account a large number of integration situations and therefore has to be built by applying situational method engineering principals and defined as a collection of reusable method chunks

Albert Camus y la tentación de la inocencia.

Resumen en español.Resumen en inglés

Le conte schwobien ou la poétique du singulier

Comprendre, comme Lucrèce, la variété des choses, c’est voir en chacune une épiphanie de l’unique, en présenter la « singularité quelconque » (Giorgio Agamben). Dans le conte poétique en prose tel que le pratique Schwob, ce regard induit un positionnement instable entre mimesis et absence de représentation. La lecture heuristique, détour trompeur mais indispensable avant une lecture herméneutique, privilégie chez l’auteur de Cœur double et du Roi au masque d’or l’émotion, l’effet, la « sidération ». Mais en même temps, et là réside la force des textes génériquement ambigus qui composent ces deux recueils, la « tendance hallucinatoire » que Schwob attribue à l’image déclinée comme hypotypose permet de saisir vivement l’unicité d’un référent particulier. Cette singularité à la fois quelconque et irréductible, qui transfère sur le monde référentiel le caractère non catégorisable que Benedetto Croce voyait dans l’objet esthétique, confère au « conte » schwobien une poétique aux contours changeants, imprévisibles. L’« effet-recueil » ne remet pas totalement en question a posteriori la singularité de chacun de ces textes prépubliés, et les préfaces elles-mêmes sont des cartes perverses, au sens propre, qui indiquent des pistes de lecture en même temps que leurs déviations.Understanding the diversity of things, as Lucretius did, means seeing in each and every one of them an epiphany of uniqueness: exhibiting their “whatever singularity” (G. Agamben). In Schwob’s practice of the prose poetic tale, this vision results in an unstable position between mimesis and the absence of representation. A heuristic reading, a deceiving but necessary detour on the way to hermeneutic reading, enhances emotions and stunning effects in the tales of Cœur double and Le Roi au masque d’or. Yet at the same time, the “hallucinatory potency” which Schwob attributes to images treated as hypotyposes enables one to grasp the uniqueness of a particular referent: there lies the strength of these generically ambiguous texts in both collections. “Whatever singularity” is therefore made singular again, and what is peculiar to the aesthetic object according to B. Croce, namely the impossibility to categorize it, is transferred upon the referential world. The “collection effect” does not entirely question a posteriori the singularity of each of these pre-published texts, and even the author’s prefaces seem to offer properly speaking “perverse” road maps by indicating ways of reading these narratives as well as alternative ways

Learning to diagnose cirrhosis from radiological and histological labels with joint self and weakly-supervised pretraining strategies

Identifying cirrhosis is key to correctly assess the health of the liver. However, the gold standard diagnosis of the cirrhosis needs a medical intervention to obtain the histological confirmation, e.g. the METAVIR score, as the radiological presentation can be equivocal. In this work, we propose to leverage transfer learning from large datasets annotated by radiologists, which we consider as a weak annotation, to predict the histological score available on a small annex dataset. To this end, we propose to compare different pretraining methods, namely weakly-supervised and self-supervised ones, to improve the prediction of the cirrhosis. Finally, we introduce a loss function combining both supervised and self-supervised frameworks for pretraining. This method outperforms the baseline classification of the METAVIR score, reaching an AUC of 0.84 and a balanced accuracy of 0.75, compared to 0.77 and 0.72 for a baseline classifier.Comment: Accepted at IEEE ISBI 202

Non-Redundant Combination of Hand-Crafted and Deep Learning Radiomics: Application to the Early Detection of Pancreatic Cancer

We address the problem of learning Deep Learning Radiomics (DLR) that are not redundant with Hand-Crafted Radiomics (HCR). To do so, we extract DLR features using a VAE while enforcing their independence with HCR features by minimizing their mutual information. The resulting DLR features can be combined with hand-crafted ones and leveraged by a classifier to predict early markers of cancer. We illustrate our method on four early markers of pancreatic cancer and validate it on a large independent test set. Our results highlight the value of combining non-redundant DLR and HCR features, as evidenced by an improvement in the Area Under the Curve compared to baseline methods that do not address redundancy or solely rely on HCR features.Comment: CaPTion workshop MICCAI 202

The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days of muscle unloading

In the light of the dynamic nature of habitual plantar flexor activity, we utilized an incremental isokinetic exercise test (IIET) to assess the work-related power deficit (WoRPD) as a measure for exercise-induced muscle fatigue before and after prolonged calf muscle unloading and in relation to arterial blood flow and muscle perfusion. Eleven male subjects (31 ± 6 years) wore the HEPHAISTOS unloading orthosis unilaterally for 56 days. It allows habitual ambulation while greatly reducing plantar flexor activity and torque production. Endpoint measurements encompassed arterial blood flow, measured in the femoral artery using Doppler ultrasound, oxygenation of the soleus muscle assessed by near-infrared spectroscopy, lactate concentrations determined in capillary blood and muscle activity using soleus muscle surface electromyography. Furthermore, soleus muscle biopsies were taken to investigate morphological muscle changes. After the intervention, maximal isokinetic torque was reduced by 23·4 ± 8·2% (P<0·001) and soleus fibre size was reduced by 8·5 ± 13% (P = 0·016). However, WoRPD remained unaffected as indicated by an unchanged loss of relative plantar flexor power between pre- and postexperiments (P = 0·88). Blood flow, tissue oxygenation, lactate concentrations and EMG median frequency kinematics during the exercise test were comparable before and after the intervention, whereas the increase of RMS in response to IIET was less following the intervention (P = 0·03). In conclusion, following submaximal isokinetic muscle work exercise-induced muscle fatigue is unaffected after prolonged local muscle unloading. The observation that arterial blood flow was maintained may underlie the unchanged fatigability