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Gamma-ray bursts are the strongest explosions in the Universe since the Big Bang, believed to be produced either in forming black holes at the end of massive star evolution or merging of compact objects. Spectral and timing properties of gamma-ray bursts suggest that the observed bright gamma-rays are produced in the most relativistic jets in the Universe; however, the physical properties, especially the structure and magnetic topologies in the jets are still not well known, despite several decades of studies. It is widely believed that precise measurements of the polarization properties of gamma-ray bursts should provide crucial information on the highly relativistic jets. As a result there have been many reports of gamma-ray burst polarization measurements with diverse results, see, however many such measurements suffered from substantial uncertainties, mostly systematic. After the first successful measurements by the GAP and COSI instruments, here we report a statistically meaningful sample of precise polarization measurements, obtained with the dedicated gamma-ray burst polarimeter, POLAR onboard China's Tiangong-2 spacelab. Our results suggest that the gamma-ray emission is at most polarized at a level lower than some popular models have predicted; although our results also show intrapulse evolution of the polarization angle. This indicates that the low polarization degrees could be due to an evolving polarization angle during a gamma-ray burst., 34 pages, 15 figures (16 pages and 3 figures without supplementary information). Accepted for publication in Nature Astronomy, http://dx.doi.org/10.1038/s41550-018-0664-0

POLAR is a compact space-borne detector designed to perform reliable measurements of the polarization for transient sources like Gamma-Ray Bursts in the energy range 50-500keV. The instrument works based on the Compton Scattering principle with the plastic scintillators as the main detection material along with the multi-anode photomultiplier tube. POLAR has been launched successfully onboard the Chinese space laboratory TG-2 on 15th September, 2016. In order to reliably reconstruct the polarization information a highly detailed understanding of the instrument is required for both data analysis and Monte Carlo studies. For this purpose a full study of the in-orbit performance was performed in order to obtain the instrument calibration parameters such as noise, pedestal, gain nonlinearity of the electronics, threshold, crosstalk and gain, as well as the effect of temperature on the above parameters. Furthermore the relationship between gain and high voltage of the multi-anode photomultiplier tube has been studied and the errors on all measurement values are presented. Finally the typical systematic error on polarization measurements of Gamma-Ray Bursts due to the measurement error of the calibration parameters are estimated using Monte Carlo simulations., Comment: 43 pages, 30 figures, 1 table; Preprint accepted by NIMA

POLAR is a new satellite-born detector aiming to measure the polarization of an unprecedented number of Gamma-Ray Bursts in the 50-500 keV energy range. The instrument, launched on-board the Tiangong-2 Chinese Space lab on the 15th of September 2016, is designed to measure the polarization of the hard X-ray flux by measuring the distribution of the azimuthal scattering angles of the incoming photons. A detailed understanding of the polarimeter and specifically of the systematic effects induced by the instrument's non-uniformity are required for this purpose. In order to study the instrument's response to polarization, POLAR underwent a beam test at the European Synchrotron Radiation Facility in France. In this paper both the beam test and the instrument performance will be described. This is followed by an overview of the Monte Carlo simulation tools developed for the instrument. Finally a comparison of the measured and simulated instrument performance will be provided and the instrument response to polarization will be presented., Preprint Accepted for Publication in Nuclear Instruments and Methods in Physics Research A

The POLAR detector is a space based Gamma Ray Burst (GRB) polarimeter with a wide field of view, which covers almost half the sky. The instrument uses Compton scattering of gamma rays on a plastic scintillator hodoscope to measure the polarization of the incoming photons. The instrument has been successfully launched on board of the Chinese space laboratory Tiangong 2 on September 15, 2016. The construction of the instrument components is described in this article. Details are provided on problems encountered during the construction phase and their solutions. Initial performance of the instrument in orbit is as expected from ground tests and Monte Carlo simulation.

The Gamma-ray Burst Polarimeter-POLAR is a highly sensitive detector which is dedicated to the measurement of GRB’s polarization with a large effective detection area and a large field of view (FOV). The optimized performance of POLAR will contribute to the capture and measurement of the transient sources like GRBs and Solar Flares. The detection energy range of POLAR is 50 keV ~ 500 keV, and mainly dominated by the Compton scattering effect. POLAR consists of 25 detector modular units (DMUs), and each DMU is composed of low Z material Plastic Scintillators (PS), multi-anode photomultipliers (MAPMT) and multi-channel ASIC Front-end Electronics (FEE). POLAR experiment is an international collaboration project involving China, Switzerland and Poland, and is expected to be launched in September in 2016 onboard the Chinese space laboratory “Tiangong-2 (TG-2)”. With the efforts from the collaborations, POLAR has experienced the Demonstration Model (DM) phase, Engineering and Qualification Model (EQM) phase, Qualification Model (QM) phase, and now a full Flight Model (FM) of POLAR has been constructed. The FM of POLAR has passed the environmental acceptance tests (thermal cycling, vibration, shock and thermal vacuum tests) and experienced the calibration tests with both radioactive sources and 100% polarized Gamma-Ray beam at ESRF after its construction. The design of POLAR, Monte-Carlo simulation analysis, as well as the performance test results will all be introduced in this paper.

Gamma-ray polarimetry is a new powerful tool to study the processes responsible for the emission from astrophysical sources and the environments in which this emission takes place. Few successful polarimetric measurements have however been performed thus far in the gamma-ray energy band due to the difficulties involved. POLAR is a dedicated polarimeter designed to perform high precision measurements of the polarization of the emission from gamma-ray burst in the 50-500 keV energy range. This new polarimeter is expected to detect approximately 50 gamma-ray bursts per year while performing high precision polarization measurements on approximately 10 bursts per year. The instrument was launched into lower earth orbit as part of the second Chinese space lab, the Tiangong-2, on September 15th 2016 and has been taking data successfully since being switched on one week after. The instrument uses a segmented scintillator array consisting of 1600 plastic scintillator bars, read out by 25 flat-panel multi-anode photomultipliers, to measure the Compton scattering angles of incoming photons. The small segmentation and relatively large uniform effective area allow the instrument to measure the polarization of a large number of transient events, such as gamma-ray bursts, with an unprecedented precision during its two year life-time. The final flight model underwent detailed calibration prior to launch as well as intensive space qualification tests, a summary of which will be presented in this paper. The instrument design will be discussed first followed by an overview of the on-ground tests, finally the in-orbit behavior as measured during the first weeks of the mission will be presented.

Resume Objectif Evaluer la sensibilite et la specificite de l’IRM pour distinguer les tumeurs urotheliales vesicales superficielles et infiltrantes. Materiel et methodes Soixante patients (52 hommes et huit femmes), d’âge moyen 66,8 ans, ont beneficie entre mai 2002 et novembre 2005, d’une IRM vesicale pour une premiere tumeur de vessie diagnostiquee par endoscopie, suivie d’une resection endoscopique de tumeur de vessie avec examen anatomopathologique. Le suivi des patients pour lesquels il existait une discordance entre IRM et analyse histologique a ete analyse. Resultats La stadification de 49 tumeurs de vessie (40 superficielles et neuf infiltrantes) etait concordante entre imagerie et anatomopathologie. Dix tumeurs vues infiltrantes a l’IRM etaient superficielles a l’analyse histologique et parmi elles, six ont recidive sur la cicatrice de resection a un ou trois mois. La sensibilite de l’IRM etait de 80 % pour une specificite de 90 %. La valeur predictive positive de cet examen etait de 97,5 %. Conclusion L’IRM a ete un examen fiable pour affirmer le caractere superficiel des tumeurs de vessie. Lorsque l’IRM et l’analyse histologique d’une resection de tumeur de vessie etaient discordantes, une resection de second look etait souhaitable pour traiter une maladie residuelle presente dans notre serie dans 60 % des cas.

Gamma Ray Bursts (GRBs) are the strongest explosions in the universe which might be associated with creation of black holes. Magnetic field structure and burst dynamics may influence polarization of the emitted gamma-rays. Precise polarization detection can be an ultimate tool to unveil the true GRB mechanism. POLAR is a space-borne Compton scattering detector for precise measurements of the GRB polarization. It consists of a 40$\times$40 array of plastic scintillator bars read out by 25 multi-anode PMTs (MaPMTs). It is scheduled to be launched into space in 2016 onboard of the Chinese space laboratory TG2. We present a dedicated methodology for POLAR calibration and some calibration results based on the combined use of the laboratory radioactive sources and polarized X-ray beams from the European Synchrotron Radiation Facility. They include calibration of the energy response, computation of the energy conversion factor vs. high voltage as well as determination of the threshold values, crosstalk contributions and polarization modulation factors., Comment: 2015 IEEE NSS conference proceedings

The complexity of caring for the ageing heart failure (HF) population is further complicated by concomitant chronic conditions (i.e., polypharmacy, depression), age related impairments (i.e., hearing, visual and cognitive impairments, impairments in activities of daily living (ADL/IADL), and other issues (e.g., health illiteracy, lack of social support). This paper provides an overview of these risk factors, outlines how they individually and in interplay endanger favourable outcome by putting patients at risk for poor self-management. Moreover, suggestions are made on how these issues could be addressed and integrated in heart failure management by applying gerontological care principles in caring for the ageing heart failure population.

Resume Introduction. – Le purpura rhumatoide est une des vascularites systemiques les plus frequentes. L’atteinte musculaire est rare, en particulier chez l’adulte et sa physiopathologie mal elucidee. Nous rapportons une observation au cours de laquelle les donnees histologiques et radiologiques mettent en evidence un hematome intramusculaire secondaire a une vascularite leucocytoclasique revele par une deglobulisation profonde. Exegese. – Un homme âge de 68 ans, traite par antivitamine K pour une maladie thromboembolique veineuse recidivante, presente un purpura rhumatoide caracterise par une glomerulonephrite segmentaire a depots d’immunoglobulines A, une vascularite necrosante cutanee et des douleurs abdominales. Les lesions dermatologiques et digestives evoluent favorablement sous corticotherapie, mais on constate une deglobulisation severe au onzieme jour de traitement rapidement rattachee a de volumineux hematomes intramusculaires bilateraux des membres inferieurs. L’examen histologique confirme que la vascularite est responsable des suffusions hemorragiques. L’echographie et l’imagerie par resonance magnetique ont permis de mieux preciser morphologiquement l’etendue des hematomes. Conclusion. – Les hematomes intramusculaires sont exceptionnels au cours du purpura rhumatoide. Ils sont la consequence d’une vascularite a complexes immuns dont le traitement est difficile. Dans notre observation, la corticotherapie a forte dose a ete insuffisante a en juguler l’evolution.

PRINCIPLES International guidelines for heart failure (HF) care recommend the implementation of inter-professional disease management programmes. To date, no such programme has been tested in Switzerland. The aim of this randomised controlled trial (RCT) was to test the effect on hospitalisation, mortality and quality of life of an adult ambulatory disease management programme for patients with HF in Switzerland. METHODS Consecutive patients admitted to internal medicine in a Swiss university hospital were screened for decompensated HF. A total of 42 eligible patients were randomised to an intervention (n = 22) or usual care group (n = 20). Medical treatment was optimised and lifestyle recommendations were given to all patients. Intervention patients additionally received a home visit by a HF-nurse, followed by 17 telephone calls of decreasing frequency over 12 months, focusing on self-care. Calls from the HF nurse to primary care physicians communicated health concerns and identified goals of care. Data were collected at baseline, 3, 6, 9 and 12 months. Mixed regression analysis (quality of life) was used. Outcome assessment was conducted by researchers blinded to group assignment. RESULTS After 12 months, 22 (52%) patients had an all-cause re-admission or died. Only 3 patients were hospitalised with HF decompensation. No significant effect of the intervention was found on HF related to quality of life. CONCLUSIONS An inter-professional disease management programme is possible in the Swiss healthcare setting but effects on outcomes need to be confirmed in larger studies.

To determine the sensitivity and specificity of MRI to distinguish between superficial and invasive transitional cell bladder cancer.Sixty patients (52 men and eight women) with a mean age of 66.8 years were assessed by bladder MRI between May 2002 and November 2005 for a primary bladder cancer diagnosed by endoscopy, followed by transurethral resection and histological examination of the bladder cancer. Patients presenting a discordance between MRI findings and histological examination were analysed.Imaging and pathology staging was concordant for 49 bladder cancers (40 superficial and nine invasive). Ten tumours considered to be invasive on MRI were superficial on histological examination and six of them relapsed at the resection scar at one or three months. The sensitivity of MRI was 80% for a specificity of 90% and a positive predictive value of 97.5%.MRI is a reliable examination to confirm the superficial nature of bladder cancer. When MRI and histological examination of a bladder cancer resection specimen are discordant, second look surgery is recommended to treat residual disease, which was present in 60% of cases in the present series.

Henoch-Schonlein purpura is one of the most frequent systemic vasculitis in children. In adults, muscle involvement is extremely rare and not very well characterized. We report a case of Henoch-Schonlein purpura with severe skin and renal involvement in witch multiple intramuscular haematoma leaded to severe anaemia. Histological examination confirms the muscle localization of the disease.A 68 years old man treated by oral anticoagulation for multiple venous thrombosis, was admitted with necrotic vasculitis of the skin, abdominal pain and segmental IgA glomerulopathy. The diagnosis of Henoch-Schonlein purpura was rapidly made and intensive steroid therapy started. After rapid improvement, a haemorrhagic shock due to voluminous intramuscular haematoma was diagnosed by MRI. Histological examination of the muscle, confirms the localization of the disease.Intramuscular haematomas are very uncommon in Henoch-Schonlein purpura. There are usually a consequence of muscular immune complex vasculitis. In our patient, high dose corticosteroid was not unable to control the disease.

Objectifs Presenter les aspects normaux et pathologiques des valves mecaniques aortiques explorees par scanner cardiaque multicoupe et notamment l’apport de la synchronisation a l’ECG pour leur etude fonctionnelle. Materiels et methodes Revue de la litterature des differentes complications possibles des valves mecaniques aortiques et presentation de leur aspect scanographique normal en fonction du type de prothese. Chaque exemple est illustre par un cas clinique realise sur un scanner 16 detecteurs (Lightspeed 16, GE Medical Systems) ou 64 detecteurs (VCT, GE Medical Systems) avec synchronisation cardiaque. Resultats La connaissance de l’aspect normal des valves mecaniques aortiques au scanner est necessaire a la recherche de leurs complications specifiques. L’acquisition avec synchronisation cardiaque permet a la fois une etude fonctionnelle de la prothese mais egalement de s’affranchir des artefacts lies aux battements cardiaques de l’aorte ascendante et donc de realiser un bilan morphologique precis. Les dysfonctionnements de prothese, leurs complications infectieuses et thrombotiques ainsi que les desinsertions totales ou partielles seront abordes. Conclusion Le scanner multicoupe, couple a la synchronisation cardiaque, permet une excellente evaluation morphologique et fonctionnelle des protheses valvulaires mecaniques aortiques et de leurs complications.

Objectifs Proposer une revue iconographique scanographique de l’anatomie normale du systeme veineux coronaire et de ses principales variations anatomiques. Decrire l’utilite des outils de post-traitement actuels pour realiser un bilan morphologique prealable aux explorations electrophysiologiques endocavitaires. Materiels et methodes Analyse retrospective d’une serie de 60 patients consecutifs sur une periode de deux mois ayant beneficie d’un scanner 16 coupes avec synchronisation cardiaque (Lightspeed 16, GEMS) pour exploration des arteres coronaires. Recensement des variations de l’anatomie veineuse coronaire au sein de la population etudiee. Evaluation de la faisabilite du post-traitement permettant une cartographie fiable du systeme veineux. Resultats Tous les examens consideres comme interpretables pour l’analyse du reseau arteriel coronaire le sont egalement pour celle du systeme veineux. La recherche de variations anatomiques est rendue aisee par les reconstructions en rendu volumique. Les techniques de post-traitement actuelles permettent une appreciation fiable de la morphologie des cavites cardiaques, du calibre des veines, de leur angulation voire de leur representation tridimentionnelle. Ces donnees non invasives doivent etre un prealable a tout examen endocavitaire et notamment avant mise en place de stimulateurs cardiaques triple chambre. Conclusion Le scanner multidetecteur avec synchronisation cardiaque permet l’etude de l’anatomie veineuse coronaire et la realisation du bilan morphologique en vue de procedures electrophysiologiques endocavitaires.

Objectifs Realiser un kit d’enseignement sur les traumatismes fermes du thorax sous la forme d’un support numerique type CD-Rom. Materiels et methodes Ce CD-Rom fonctionne sur plate-forme compatible PC. La configuration minimale comporte un PC 300 MHz avec Windows 95 et un lecteur de CD-Rom. Le choix du support numerique presente l’avantage d’un faible encombrement, de garantir une conservation dans le temps de la qualite de l’iconographie et de permettre une approche ludique et didactique du sujet. Resultats Nous avons presente de maniere interactive, a l’aide d’une revue de la litterature recente et illustree par une iconographie riche, le large eventail des pathologies relatives aux traumatismes fermes du thorax ainsi que les differentes techniques d’imagerie disponibles et la semiologie radiologique a connaitre afin d’obtenir un diagnostic precis et rapide voire de participer a la prise en charge therapeutique. Le controle des connaissances acquises est realise grâce a la presentation de dossiers radiocliniques. Conclusion La connaissance parfaite des differentes techniques d’imagerie disponibles et de la semiologie radiologique relative aux nombreuses pathologies engendrees par les traumatismes fermes du thorax est necessaire pour la prise en charge rapide et adaptee des patients.