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IMPORTANCE: Bariatric surgery has been associated with a reduced risk of cancer in individuals with obesity. The association of bariatric surgery with esophageal and gastric cancer is still controversial, however. OBJECTIVE: To compare the incidence of esophageal and gastric cancer between patients with obesity who underwent bariatric surgery and those who did not (control group). DESIGN, SETTING, AND PARTICIPANTS: This cohort study obtained data from a national discharge database, including all surgical centers, in France from January 1, 2010, to December 31, 2017. Participants included adults (aged ≥18 years) with severe obesity who underwent bariatric surgery (surgical group) or who did not (control group). Baseline characteristics were balanced between groups using nearest neighbor propensity score matching with a 1:2 ratio. The study was conducted from March 1, 2020, to June 30, 2021. EXPOSURES: Bariatric surgery (adjustable gastric banding, gastric bypass, and sleeve gastrectomy) vs no surgery. MAIN OUTCOMES AND MEASURES: The main outcome was incidence of esophageal and gastric cancer. A secondary outcome was overall in-hospital mortality. RESULTS: A total of 303 709 patients who underwent bariatric surgery (245 819 females [80.9%]; mean [SD] age, 40.2 [11.9] years) were matched 1:2 with 605 140 patients who did not receive surgery (500 929 females [82.8%]; mean [SD] age, 40.4 [12.5] years). After matching, the 2 groups of patients were comparable in terms of age, sex, and comorbidities (standardized mean difference [SD], 0.05 [0.11]), with some differences in body mass index. The mean follow-up time was 5.62 (2.20) years in the control group and 6.06 (2.31) years in the surgical group. A total of 337 patients had esophagogastric cancer: 83 in the surgical group and 254 in the control group. The incidence rates were 6.9 per 100 000 population per year for the control group and 4.9 per 100 000 population per year for the surgical group, resulting in an incidence rate ratio of 1.42 (95% CI, 1.11-1.82; P = .005). The hazard ratio (HR) of cancer incidence was significantly in favor of the surgical group (HR, 0.76; 95% CI, 0.59-0.98; P = .03). Overall mortality was significantly lower in the surgical group (HR, 0.60; 95% CI, 0.56-0.64; P < .001). CONCLUSIONS AND RELEVANCE: In this large, nationwide cohort of patients with severe obesity, bariatric surgery was associated with a significant reduction of esophageal and gastric cancer incidence and overall in-hospital mortality, which suggests that bariatric surgery can be performed as treatment for severe obesity without increasing the risk of esophageal and gastric cancer.

IMPORTANCE: Caustic ingestion in adults may result in death or severe digestive sequelae. The scarcity of nationwide epidemiological data leads to difficulties regarding the applicability of their analysis to less specialized centers, which are nevertheless largely involved in the emergency management of adverse outcomes following caustic ingestion. OBJECTIVE: To assess outcomes associated with caustic ingestion in adults across a nationwide prospective database. DESIGN, SETTINGS, AND PARTICIPANTS: Adult patients aged 16 to 96 admitted to the emergency department for caustic ingestion between January 2010 and December 2019 were identified from the French Medical Information System Database, which includes all patients admitted in an emergency setting in hospitals in France during this period. EXPOSURE: Esophageal caustic ingestion. MAIN OUTCOMES AND MEASURES: The primary end point was in-hospital patient outcomes following caustic ingestion. Multivariate analysis was performed to assess independent predictors of in-hospital morbidity and mortality. RESULTS: Among 22 657 226 patients admitted on an emergency outpatient basis, 3544 (0.016%) had ingested caustic agents and were included in this study. The median (IQR) age in this population was 49 (34-63) years, and 1685 patients (48%) were women. Digestive necrosis requiring resection was present during the primary hospital stay in 388 patients with caustic ingestion (11%). Nonsurgical management was undertaken in 3156 (89%). A total of 1198 (34%) experienced complications, and 294 (8%) died. Pulmonary complications were the most frequent adverse event, occurring in 869 patients (24%). On multivariate analysis, predictors of mortality included old age, high comorbidity score, suicidal ingestion, intensive care unit admission during management, emergency surgery for digestive necrosis, and treatment in low-volume centers. On multivariate analysis, predictors of morbidity included old age, higher comorbidity score, intensive care unit admission during management, and emergency surgery for digestive necrosis. CONCLUSIONS AND RELEVANCE: In this study, referral to expert centers was associated with improved early survival after caustic ingestion. If feasible, low-volume hospitals should consider transferring patients to larger centers instead of attempting on-site management.

The low-dose (1 µg) ACTH test (LDT) is widely used to assess central adrenal insufficiency (CAI); however, the serum cortisol cutoff value is controversial. Salivary cortisol (SC) may be a more accurate measurement for CAI.

L’ESG est plus efficace que les mesures hygiénodiététiques seules pour la perte de poids et l’amélioration des comorbidités liées à l’obésité. Bien qu’elle ait un effet moindre sur la perte de poids par rapport à la sleeve gastrectomie laparoscopique (SG ou LSG) à court et moyen termes, elle offre une résolution des comorbidités similaire à celle de la SG.

We present new results for ground-state candidate energies of Mg-rich olivine (MRO) clusters and use the binding energies of these clusters to determine their nucleation rates in stellar outflows, with particular interest in the environments of core-collapse supernovae (CCSNe). Low-lying structures of clusters (Mg2SiO4)n2 ≤ n ≤ 13 are determined from a modified minima hopping algorithm using an empirical silicate potential in the Buckingham form. These configurations are further refined and optimized using the density functional theory code Quantum Espresso. Utilizing atomistic nucleation theory, we determine the critical size and nucleation rates of these clusters. We find that configurations and binding energies in this regime are very dissimilar from those of the bulk lattice. Clusters grow with SiO4–MgO layering and exhibit only global, rather than local, symmetries. When compared to classical nucleation theory we find suppressed nucleation rates at most temperatures and pressures, with enhanced nucleation rates at very large pressures. This implies a slower progression of silicate dust formation in stellar environments than previously assumed.

We study nonparametric identification of single‐agent discrete choice models for bundles (without requiring bundle‐specific prices) and of binary games of complete information. We show that these two models are quite similar from an identification standpoint. Moreover, they are mathematically equivalent when we restrict attention to the class of potential games and impose a specific equilibrium selection mechanism in the data generating process. We provide new identification results for the two related models.

De nouveaux seuils en chirurgie digestive carcinologique seront appliqués en 2023 accréditant les établissements avec des seuils spécifiques pour les interventions lourdes. L'objectif était de rapporter le gain de survie à 90 jours postopératoires lié à l'application de cette réforme.

Aims.4U 2129+47was discovered in the early 80's and classified as an accretion disk corona source due to its broad and partial X-ray eclipses. The 5.24 h binary orbital period was inferred from the X-ray and optical light curve modulation, implying a late K or M spectral type companion star. The source entered a low state in 1983, during which the optical modulation disappeared and an F8 IV star was revealed, suggesting that 4U 2129+47might be part of a triple system. The nature of 4U 2129+47has since been investigated, but no definitive conclusion has been reached.

Context.New information on short/hard gamma-ray bursts (GRBs) is being gathered thanks to the discovery of their optical and X-ray afterglows. However, some key aspects are still poorly understood, including the collimation level of the outflow, the duration of the central engine activity, and the properties of the progenitor systems.

Aims.The aim of this paper is to study the Gamma Ray Burst (GRB) environment through the analysis of the optical absorption features due to the gas surrounding the GRB.

Context.GRB 050721 was detected by Swiftand promptly followed-up, in the X-ray by Swiftitself and, in the optical band, by the VLT operated, for the first time, in rapid response mode starting observations about 25 m after the burst. A multiwavelength monitoring campaign was performed in order to study its afterglow's behavior.

Short duration ($\la $2 s) Gamma-ray bursts (GRBs) have been a mystery since their discovery. Until May 2005 very little was known about short GRBs, but this situation has changed rapidly in the last few months since the Swift and HETE-2 satellites have made it possible to discover X-ray and optical counterparts to these sources. Positional associations indicate that short GRBs arise in close-by galaxies ($z<0.7$). Here we report on a detailed study of the short GRB 050724 X-ray afterglow. This burst shows strong flaring variability in the X-ray band. It clearly confirms early suggestions of X-ray activity in the 50–100 s time interval following the GRB onset seen with BATSE. Late flare activity is also observed. These observations support the idea that flares are related to the inner engine for short GRBs, as well as long GRBs.

We present the constraints on the cosmological parameters obtained with the Epeak–$E_{\gamma}$correlation found with the most recent sample of 19 GRBs with spectroscopically measured redshift and well determined prompt emission spectral and afterglow parameters. We compare our results obtained in the two possible uniform jet scenarios, i.e. assuming a homogeneous density profile (HM) or a wind density profile (WM) for the circumburst medium. 
We explore the improvements to the constraints of the cosmological parameters that could be reached with a large sample, ~150 GRBs, in the future. Finally, we study the possibility to calibrate the slope of these correlations. Our optimization analysis suggests that ∼12 GRBs with redshift $z\in(0.9,1.1)$can be used to calibrate the Epeak–$E_{\gamma}$with a precision better than 1%. The same precision is expected for the same number of bursts with $z\in(0.45,0.75)$. This result suggests that we do not necessarily need a large sample of low zGRBs for calibrating the slope of these correlations.

We studied the optical afterglows of the 24 pre-SWIFT gamma-ray bursts (GRBs) with both known spectroscopic redshift and published estimates of the optical extinction in the source frame. We found an unexpected clustering of the optical-afterglow luminosities measured 12 h (source frame time) after the trigger. For 21 out of 24 bursts, the distribution of the optical luminosities is narrower than the distribution of the X-ray luminosities, and even narrower than the distribution of the ratio between the monochromatic optical luminosities and the total isotropic, emitted prompt energy. Three bursts stand out from the distribution of the other sources, being underluminous by a factor ~15. We compare this result with another somewhat analogous result concerning the luminosity of the X-ray afterglows studied earlier. We constructed the optical to X-ray spectral energy distribution for all our GRBs. For all but a minority of them, the optical and the X-ray emissions are consistent with being produced by the same radiation process. We discuss our results in the framework of the “standard” external-shock synchrotron model. Finally, we consider the behavior of the first GRBs of known redshifts detected by SWIFT. We find that these SWIFT GRBs entirely confirm our findings.

Gamma-ray burst (GRB) progenitors are observationally linked to the death of massive stars. X-ray studies of the GRB afterglows can deepen our knowledge of the ionization status and metal abundances of the matter in the GRB environment. Moreover, the presence of local matter can be inferred through its fingerprints in the X-ray spectrum, i.e. the presence of absorption higher than the Galactic value. A few studies based on BeppoSAX and XMM-Newton found evidence of higher than Galactic values for the column density in a number of GRB afterglows. Here we report on a systematic analysis of 17 GRBs observed by Swift up to April 15, 2005. We observed a large number of GRBs with an excess of column density. Our sample, together with previous determinations of the intrinsic column densities for GRBs with known redshift, provides evidence for a distribution of absorption consistent with that predicted for randomly occurring GRB within molecular clouds.

We present optical observations of the short/hard gamma-ray burst GRB 050709, the first such event with an identified optical counterpart. The object is coincident with a weak X-ray source and is located inside a galaxy at redshift $z = 0.1606 \pm 0.0002$. Multiband photometry allowed us to study the broad-band spectral energy distribution.
Late-time monitoring places strong limits on any supernova simultaneous with the GRB. The host galaxy is not of early type. Spectra show that the dominant stellar population is relatively young (∼1 Gyr), and that ongoing star formation is present at a level of $2\mbox{--}3\,L/L_*~M_\odot$yr-1. This is at least 2 orders of magnitude larger than that observed in the elliptical hosts of the short GRB 050509B and GRB 050724. This shows that at least some short GRBs originate in a young population. Short/hard GRB models based on the merger of a binary degenerate system are compatible with the host galaxy characteristics, although there is still the possibility of a connection between young stars and at least a fraction of such events.

We present optical and near-infrared observations of the afterglow of the gamma-ray burst GRB 050904. We derive a photometric redshift $z = 6.3$, estimated from the presence of the Lyman break falling between the Iand Jfilters. This is by far the most distant GRB known to date. Its isotropic-equivalent energy is $3.4 \times 10^{53}$erg in the rest-frame 110-1100 keV energy band. Despite the high redshift, both the prompt and the afterglow emission are not peculiar with respect to other GRBs. We find a break in the J-band light curve at $t_{\rm b} = 2.6 \pm 1.0$d (observer frame). If we assume this is the jet break, we derive a beaming-corrected energy $E_\gamma \sim (4 \div 12) \times 10^{51}$erg. This limit shows that GRB 050904 is consistent with the Amati and Ghirlanda relations. This detection is consistent with the expected number of GRBs at $z > 6$and shows that GRBs are a powerful tool to study the star formation history up to very high redshift.

We present an optical-to-X-ray spectral analysis of the afterglow of GRB 020405. The optical spectral energy distribution not corrected for the extragalactic extinction is significantly below the X-ray extrapolation of the single powerlaw spectral model suggested by multiwavelength studies. We investigate whether considerable extinction could explain the observed spectral “mismatch” by testing several types of extinction curves. For the first time we test extinction curves computed with time-dependent numerical simulations of dust grains destruction by the burst radiation. We find that an extinction law weakly dependent on wavelength can reconcile the unabsorbed optical and X-ray data with the expected synchrotron spectrum. A gray extinction law can be provided by a dust grain size distribution biased toward large grains.

We describe the construction of the Brera Multi-scale Wavelet (BMW) HRI Cluster Survey, a deep sample of serendipitous X-ray selected clusters of galaxies based on the ROSAT HRI archive. This is the first cluster catalog exploiting the high angular resolution of this instrument. Cluster candidates are selected on the basis of their X-ray extension only, a parameter which is well measured by the BMW wavelet detection algorithm. The survey includes 154 candidates over a total solid angle of ~160 deg2at 10-12erg s-1cm-2and ~80 deg2at $1.8\times10^{-13}$erg s-1cm-2. At the same time, a fairly good sky coverage in the faintest flux bins ($3{-}5 \times 10^{-14}$erg s-1cm-2) gives this survey the capability of detecting a few clusters with $z\sim 1{-}1.2$, depending on evolution. We present the results of extensive Monte Carlo simulations, providing a complete statistical characterization of the survey selection function and contamination level. We also present a new estimate of the surface density of clusters of galaxies down to a flux of $3\times 10^{-14}$erg s-1cm-2, which is consistent with previous measurements from PSPC-based samples. Several clusters with redshifts up to $z=0.92$have already been confirmed, either by cross-correlation with existing PSPC surveys or from early results of an ongoing follow-up campaign. Overall, these results indicate that the excellent HRI PSF (5´´  FWHMon axis) more than compensates for the negative effect of the higher instrumental background on the detection of high-redshift clusters. In addition, it allows us to detect compact clusters that could be lost at lower resolution, thus potentially providing an important new insight into cluster evolution.

GRB 020410 is by far the longest γ-ray burst (with a duration of about 1600 s) to have been followed up from the X-ray through the radio regime. Afterglow emission was detected in X-rays and at optical wavelengths whereas no emission was detected at 8 GHz brighter than 120 μJy. The decaying X-ray afterglow, back-extrapolated to 11 h after the burst, had a flux of 7.9 $\times$10-12erg cm-2s-1(2–10 keV); the brightest detected so far. No direct redshift determination is available yet for this GRB, but according to the empirical relationship between the peak energy in the $\nu F_\nu$spectrum and the isotropic energy output, zis constrained in the range 0.9–1.5. The reconstructed optical afterglow light curve implies at least two breaks in the simple power law decay. This may be related to emergence of an SN, or refreshment of the external shock by a variation in the circumstellar medium. Considering the backward extrapolation of the 2–10 keV afterglow decay, the prompt lightcurve variability and its spectral evolution, we conclude that the long duration of this event is due to a prolonged activity of the “central engine”.

We present the results of a VLT polarimetric monitoring campaign of the GRB 020813 optical afterglow carried out in three nights, from 0.88 to 4.20 days after the gamma-ray event. The mean values of the degree of linear polarization (P) and its position angle (θ) resulting from our campaign are $\langle P\rangle=1.18 \pm 0.10 \%$and $\langle \theta\rangle = 148.7^{\circ} \pm 2.3^{\circ}$, after correcting for Galactic interstellar polarization. Our VLT data set is most naturally described by a constant degree of linear polarization and position angle, nonetheless a slow θevolution cannot be entirely ruled out by our data. The VLT monitoring campaign did not reveal either a significant θrotation respect to the Keck spectropolarimetric observations performed ~0.25 days after the GRB (Barth et al. [CITE]). However, $\langle P\rangle $is a factor of two lower than the polarization degree measured from Keck. Additionally, the VLT polarization data allowed us to construct an accurate V-band light curve. The V-band photometric data revealed a smooth light curve with a break located between the last Keck and our first VLT polarimetric measurement, $0.33 < t_{{\rm break}, V} < 0.88$days after the GRB. The typical magnitude fluctuations of the VLT V-band lightcurve are 0.003 mag, 0.010 mag and 0.016 mag for our three observing nights, respectively. We speculate that the stability of θmight be related to the smoothness of the light curve.

The polarization curve of GRB 020813 is discussed and compared to different models for the structure, evolution and magnetisation properties of the jet and the interstellar medium onto which the fireball impacts. GRB 020813 is best suited for this kind of analysis for the smoothness of its afterglow light curve, ensuring the applicability of current models. The polarization dataset allows us to rule out the standard GRB jet, in which the energy and Lorentz factor have a well defined value inside the jet opening angle and the magnetic field is generated at the shock front. We explore alternative models finding that a structured jet or a jet with a toroidal component of the magnetic field can fit equally well the polarization curve. Stronger conclusions cannot be drawn due to the incomplete sampling of the polarization curve. A more dense sampling, especially at early times, is required to pin down the structure of the jet and the geometry of its magnetic field.

We consider internal shocks as the main dissipation mechanism responsible for the emission in blazars and show that it can satisfactorily account for the properties of all blazars. In particular, we extend previous work (Spada et al. [CITE]) on powerful objects, to intermediate (BL Lac) and low power sources (Mkn 421), in order to reproduce the whole of the blazar sequence. The model self-consistently treats the dynamics, spectral emission and its variability. The key parameters driving the phenomenological sequence are the jet power and the properties of the broad line region, which regulate the cooling efficiency of the emitting particles and thus the shape of the spectral energy distribution. By assuming that the remaining parameters are similar for all objects it has been possible to reproduce the full range of the observed spectral “states". A more detailed comparison of the variability properties shows (for Mkn 421) a good agreement in the X-ray band, while in the optical the simulated flux appears to be too variable. For BL Lac lags (~10 days) are predicted between the γ-rays and the infrared emission.

We reanalyze the XMM–Newtondata of GRB 011211 showing that the spectral features, interpreted by Reeves et al. ([CITE], [CITE]) as due to thermal emission from a collisionally ionized plasma, can be also reproduced by a reflection model (with ionization parameter $\xi\sim 10^2$). We discuss the implications of this interpretation, estimating the total mass required in the simplified case of a funnel geometry. We conclude that a moderate clumping of the reprocessing material (corresponding to a filling factor of the order of $f\sim 10^{-3}$) is required. Finally we show that, if this interpretation is correct, a bright quasi–thermal component is expected in the optical–UV band (containing about $90\%$of the luminosity of the illuminating continuum), whose presence can be used to test the reflection model.

Polarization measurements for the optical counterpart to GRB 021004 are presented and discussed. Our observations were performed with the TNG and the VLT–UT3 (Melipal) during the first and fourth night after the gamma-ray burst discovery. We find robust evidence for temporal evolution of the polarization, which is therefore, at least partially, intrinsic to the optical transient. We do not find convincing evidence of wavelength dependence for the intrinsic polarization of the transient, in agreement with current polarization models for optical afterglows. We discuss the role of dust, both in our galaxy and in the host, in modifying the transmitted polarization vector, showing how a sizable fraction of the observed polarized flux is due to Galactic selective extinction, while it is not possible to single out any clear contribution from dust in the host galaxy. We discuss how our data compare to those obtained by different groups showing that a two-component model is required to describe the complete dataset. This is not surprising given the complex lightcurve of GRB 021004.

We present photometric and spectroscopic observations of the gamma-ray burst GRB 021211 obtained during the late stages of its afterglow. The light curve shows a rebrightening occurring ~25 days after the GRB. The analysis of a VLT spectrum obtained during the bump (27 days after the GRB) reveals a suggestive resemblance with the spectrum of the prototypical type-Ic SN 1994I, obtained ~10 days past maximum light. Particularly we have measured a strong, broad absorption feature at 3770 Å, which we have identified with Ca II blueshifted by ~$14\,400$km s-1, thus indicating that a supernova (SN) component is indeed powering the “bump” in the afterglow decay. Assuming SN 1994I as a template, the spectroscopic and photometric data together indicate that the SN and GRB explosions were at most separated by a few days. Our results suggest that GRBs might be associated also to standard type-Ic supernovae.

We present optical and near-infrared (NIR) photometry of the bright afterglow of GRB 020813. Our data span from 3 hours to 4 days after the GRB event. A rather sharp achromatic break is present in the light curve, 14 hours after the trigger. In the framework of jetted fireballs, this break corresponds to a jet half-opening angle of $1.9\degr\pm0.2\degr$, the smallest value ever inferred for a GRB. We discuss our results in the framework of currently available models, and find that they have problems in explaining the joint temporal and spectral properties, and in particular the slow decay before the break.

Polarization measurements for the optical counterpart to GRB 020405 are presented and discussed. Our observations were performed with the VLT–UT3 (Melipal) during the second and third night after the gamma–ray burst discovery. The polarization degree (and the position angle) appears to be constant between our two observations at a level around $1.5\div2\%$. The polarization can be intrinsic but it is not possible to unambiguously exclude that a substantial fraction of it is induced by dust in the host galaxy.

The presence of thermal components in the early X-ray afterglows of γ-ray bursts is investigated. We discuss both the presence of a thermal continuum and, in particular, of collisional X-ray emission lines. We compute the predicted luminosity by a thin plasma for a range of metallicities for the continuum and the Kαlines of the elements Mg, Si, S, Ar, Ca and Fe. We show that light travel effects are dominant in the determination of the thermal continuum and line luminosities, and derive the relevant equations. We conclude that thermal lines and continua are unlikely to dominate the early afterglow of GRBs, unless the explosion site is surrounded by a very massive and extremely clumped shell of material. Such conditions are difficult to envisage in the close environment of the GRB progenitor, unless they are excited by some strong precursor activity, like in the Supranova scenario.

Le risque de cancer de l'œsophage et de l'estomac après une chirurgie bariatrique est débattu. Plusieurs études ont rapporté que les patients opérés d'une chirurgie bariatrique ont un risque plus faible de cancer. Cependant, les cancers de l'œsophage et de l'estomac sont associés à des facteurs de risque spécifiques, qui pourraient augmenter après chirurgie bariatrique. L'objectif de cette étude est d'évaluer si la chirurgie bariatrique est associée à un risque plus élevé de cancer œsogastrique à l'échelle nationale.

We present a model for the early optical afterglow of GRB 021004. This burst had one of the earliest detected optical afterglows, allowing for a dense optical sampling. The lightcurve was peculiar, since bright bumps were superimposed to the regular power-law decay observed in many other events. We show that, given their time scale and shape, the bumps are likely due to the interaction of the fireball with moderate density enhancements in the ambient medium. The enhancements have a density contrast of order 10, modifying only slightly the dynamics of the fireball, which therefore surfs on them rather than colliding into them. A relativistic reverse shock does not develop. Since the interaction takes place when the fireball is still hyper-relativistic it is not possible to understand if the overdensities are localized in clumps or are spherically symmetric around the GRB progenitor. The monotonic decrease of the contrast of successive rebrightenings suggests however the presence of clumps embedded in a uniform environment. Such an interpretation, complemented by the detection of several high velocity absorption systems in the optical spectrum, strongly suggests that GRB 021004 exploded within the remnant of a previous explosion.

We present and discuss polarimetric observations performed with the VLT–UT3 (Melipal) on the afterglow of GRB 011211, ~35 hours after the burst onset. The observations yielded a 3 σupper limit of $P<2.7\%$. We discuss this result in combination with the lightcurve evolution, that may show a break approximately at the time of our observation. We show that our upper limit is consistent with the currently favored beamed fireball geometry, especially if the line of sight was not too close to the edge of the cone.

The emission features observed in the X–ray afterglow of Gamma Ray Bursts are extremely powerful. Since they last at least for several hours, they imply energies of the order of 1049ergs. This in turn implies that the energy contained in the illuminating continuum thought to be responsible of the line production must exceed 1051ergs. This is a strong lower limit to the energy reservoir of Gamma Ray Bursts, which is independent of collimation and beaming, and bears important consequences on the possible collimation of the fireball radiation and the density of the medium surrounding the burst.

The recent report of iron line features in the afterglow of the gamma-ray burst (GRB) 991216 has important implications for the properties of the radiating material and hence the nature of the immediate burst environment. We argue that the putative strong Fe emission line can be attributed to the reflected emission from Thomson-thick matter which is illuminated by a power-law continuum. The ionization parameter of the material (i.e., the flux to density ratio) is around 103, resulting in a Fe Kαline from He-like iron. A supersolar abundance of iron is not required by the data. Interestingly, the ionizing continuum must be harder than the observed one. We interpret this as due to the fact that the observed continuum is dominated by the standard blast wave emission, while the line is produced by reprocessing material located at much smaller radii.

We report the discovery of a transient and fading hard X-ray emission in the BATSE lightcurves of a sample of short γ-ray bursts. We have summed each of the four channel BATSE light curves of 76 short bursts to uncover the average overall temporal and spectral evolution of a possible transient signal following the prompt flux. We found an excess emission peaking ~30 s after the prompt one, detectable for ≈100 s. The soft power-law spectrum and the time-evolution of this transient signal suggest that it is produced by the deceleration of a relativistic expanding source, as predicted by the afterglow model.

We present photometric and spectroscopic observations of the late afterglow of GRB 000911, starting ${\sim} 1$day after the burst event and lasting ${\sim} 8$weeks. We detect a moderately significant re-brightening in the R, Iand Jlightcurves, associated with a sizable reddening of the spectrum. This can be explained through the presence of an underlying supernova, outshining the afterglow ${\sim}30$days after the burst event. Alternative explanations are discussed.

Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). Although respiratory pathogens are frequently detected in children with ACS, their respective role in triggering the disease is still unclear. We hypothesized that the incidence of ACS followed the unprecedented population-level changes in respiratory pathogen dynamics after COVID-19-related nonpharmaceutical interventions (NPIs).

Introduction: La Société Française de Chirurgie Digestive a souhaité proposer des recommandations pour la pratique clinique portant sur les spécificités de la prise en charge en chirurgie digestive du patient adulte en situation d’obésité.

Il est désormais admis que la dénutrition augmente les complications postopératoires, en particulier respiratoires et infectieuses après chirurgie majeure. La chirurgie hépatique est principalement réalisée chez des malades porteurs de cancers, ce qui augmente le risque de dénutrition. Les principaux facteurs de risque de complications postopératoires sont l’hypoalbuminémie préopératoire et un indice de masse corporelle inférieur à 20kg/m2. Pour tenter d’améliorer la prédiction des complications chez ces patients, des équipes ont suggéré de mesurer l’épaisseur des muscles par tomodensitométrie. La masse musculaire peut être ainsi quantifiée sur une coupe axiale passant par la troisième vertèbre lombaire, en mesurant la surface totale des muscles psoas ou la surface totale de tous les muscles (i.e., muscles obliques externe et interne, muscle transverse, psoas et muscles paravertébraux) visibles sur cette coupe. Il existe de plus en plus de données qui suggèrent que la sarcopénie est un facteur indépendant de morbidité postopératoire et de faible survie à long terme après résection hépatique pour cancer. Néanmoins, la littérature reste très pauvre, le manque de définitions standardisées de la sarcopénie et le fait que les techniques reposant sur l’imagerie nécessitent l’utilisation de logiciels particuliers pour le calcul des surfaces constituent les principales limites. Enfin, il y a encore moins de données sur les moyens nutritionnels et pharmacologiques de traiter la sarcopénie. Par une revue de la littérature, nous avons fait une mise au point sur l’intérêt et l’impact pronostique de la sarcopénie dans la chirurgie des tumeurs du foie. La définition actuellement validée sur le plan international, les méthodes de mesure et les conséquences de la sarcopénie sur les résultats des hépatectomies sont détaillées dans cette revue.

Gamma-ray bursts are a complex, non-linear system that evolves very rapidly through stages of vastly different conditions. They evolve from scales of few hundred kilometers where they are very dense and hot to cold and tenuous on scales of parsecs. As such, our understanding of such a phenomenon can truly increase by combining theoretical and numerical studies adopting different numerical techniques to face different problems and deal with diverse conditions. In this review, we will describe the tremendous advancement in our comprehension of the bursts phenomenology through numerical modeling. Though we will discuss studies mainly based on jet dynamics across the progenitor star and the interstellar medium, we will also touch upon other problems such as the jet launching, its acceleration, and the radiation mechanisms. Finally, we will describe how combining numerical results with observations from Swift and other instruments resulted in true understanding of the bursts phenomenon and the challenges still lying ahead.

Internet est devenu un outil incontournable d’information dans le domaine de la santé. On estime qu’environ trois quart des patients y effectue des recherches. De plus, les patients obèses semblent particulièrement intéressés par cet outil. Cette étude analyse la qualité des sites web français les plus populaires en chirurgie bariatrique. Entre septembre et octobre 2013, nous avons sélectionné 20 sites web sur le thème de la chirurgie bariatrique. La recherche a été réalisée avec le moteur de recherche Google® en utilisant quatre mots clés : « chirurgie obésité », « by-pass gastrique », « anneau gastrique », et « sleeve ». Les sites ont été évalués grâce à un outil d’analyse des sites web recommandé par l’HAS, et classés en 3 catégories : « très bien », « bien » et « faible ». Nous avons aussi retenu pour chaque site l’organisme d’affiliation et la labellisation HON (Health On the Net). La Société Française et Francophone de Chirurgie de l’Obésité et des Maladies Métaboliques (SOFFCO-MM) a été inclus d’office. Environ la moitié des sites web retenus (9/20) émanent d’établissements de santé privés, huit sont rédigés par des organismes de communication, deux sites sont institutionnels et un seul appartient à un hôpital public. Sept sites (35 %) ont été classés « très bien », cinq (25 %) ont été classés « bien », et huit (40 %) comme « faible ». Les sites des établissements de santé (publiques ou privés) ont obtenu de meilleurs résultats comparé aux sites rédigés par des organismes de communication ou par des institutions (p<0,05). Les sites labélisés HON (n=4) ont un score de qualité supérieur aux sites (n=16) non labélisés (p<0,05). La popularité des sites web dans le moteur de recherche est faiblement corrélée au classement de qualité (r= -0,493, p=0,27). Les sites web français traitant de chirurgie de l’obésité sont hétérogènes. Environ un tiers d’entre eux est de bonne qualité, en particulier ceux qui sont rédigés par des professionnels de santé. Cependant les hôpitaux publics semblent peu impliqués dans ce type de communication. Internet has become a capital source of health information as almost three patients out of four make research on health care. Moreover, obese patients seem to be particularly interested by this tool. We analysed the quality of the most popular French bariatric surgery websites. Between September to October 2013, we selected 20 websites on bariatric surgery. The research was conducted using Google® and using the following keywords: “obesity surgery”, “gastric bypass”, “gastric banding”, and “sleeve”. Retrieved websites were assessed with an evaluation tool recommended by the French High Authority for Health (HAS) and classified in 3 categories “very good”, ”good” and “low”. Affiliation and Health On the Net (HON) label were retrieved for each website. The French and French-Speaking Society of Obesity Surgery and Metabolic Disease (SOFFCO-MM) website was automatically included. Almost half of the retrieved studies (9/20) belong to private hospitals, eight to media, two are institutional and only one is drafted by a public hospital. Seven websites (35%) have been noted as “very good”, five (25%) as “good”, and eight (40%) as “low”. Hospitals (public or private) make better websites than institutions or media (p<0.05). Websites with a HON label had a significantly higher score (p<0.05). Popularity and quality of websites are poorly correlated (r= −0.493, p=0.27). Quality of French websites on bariatric surgery is disparate. Almost one third has a good quality, particularly when written by health professionals. Nevertheless public hospitals seem to be poorly involved in this mean of communication.

Mesenchymal stem cells (MSC) and adipose-derived stem cells (ASC) were recently proposed for bone maxillo-facial reconstruction in association with biomaterials. For this application MSC must be ex-vivo expanded in order to obtain, for a given volume of implanted biomaterial, a relevant number of bone forming cells. Previously conducted pre-clinical studies suggested that a concentration of 6 × 108ASC associated with 900 mg of anorganic bovine bone (ABB) could be effective for human maxillary sinus floor elevation. A keystone issue to guarantee the quality and safety of Advanced Therapy Medicinal Products containing expanded MSC and ASC is their chromosome stability in culture: this topic has been widely investigated and conflicting results have been published. Abnormal karyotype of human ex-vivo expanded MSC and ASC was found by some authors, while, at the same time, several other studies showed the MSC and ASC karyotype to be normal. It is therefore important that all the results obtained on MSC and ASC karyotype analysis be published. Given this context, the aim of this manuscript, aim of this manuscript is to verify the karyotype stability of ASC in view of their applications in clinical trials. ASC obtained from the adipose tissue of 4 donors were expanded over extended culture time. Based on previous ASC expansions we hypothesized to be able to obtain 6 × 108cells by passage 7. Karyotype analysis of 30 metaphases was planned to be investigated at passage 2, 7, and 15 in all the cultures. No abnormalities were found in the karyotype of two donors at all the passages tested, while a translocation was found in 2 metaphases of a donor at passage 7, but not at passage 15, and in the fourth donor in 5 metaphases a trisomy was found at passage 15. Chromosomal abnormalities were detected only after extended ASC expansion. Whether these anomalies can be related to risk for the patient's safety will have to be demonstrated by in-vivo studies.

We study the spectrum of high-frequency radiation emerging from mildly dissipative photospheres of long-duration gamma-ray burst outflows. Building on the results of recent numerical investigations, we assume that electrons are heated impulsively to mildly relativistic energies by either shocks or magnetic dissipation at Thomson optical depths of several and subsequently cool by inverse Compton, scattering off the thermal photons of the photosphere. We show that even in the absence of magnetic field and non-thermal leptons, inverse Compton scattering produces power-law tails that extend from the peak of the thermal radiation, at several hundred keV, to several tens of MeV, and possibly up to GeV energies. The slope of the high-frequency power law is predicted to vary substantially during a single burst, and the model can easily account for the diversity of high-frequency spectra observed by BATSE. Our model works in baryonic as well as in magnetically dominated outflows, as long as the magnetic field component is not overwhelmingly dominant.

We present the results of hydrodynamical simulations of gamma-ray burst (GRB) jets propagating through their stellar progenitor material and subsequently through the surrounding circumstellar medium. We consider both jets that are injected with constant properties in the center of the star and jets injected with a variable luminosity. We show that the variability properties of the jet outside the star are a combination of the variability injected at the base of the jet and the variability caused by the jet propagation through the star. Comparing power spectra for the two cases shows that the variability injected by the engine is preserved even if the jet is heavily shocked inside the star. Such shocking produces additional variability at long timescales, of order several seconds. Within the limited number of progenitors and jets investigated, our findings suggest that the broad pulses of several seconds duration typically observed in GRBs are due to the interaction of the jet with the progenitor, while the short-timescale variability, characterized by fluctuations on timescales of milliseconds, has to be injected at the base of the jet. Studying the properties of the fast variability in GRBs may therefore provide clues to the nature of the inner engine and the mechanisms of energy extraction from it.

We present two-dimensional (2D) high-resolution hydrodynamic simulations of the relativistic outflows of long-duration gamma-ray burst (GRB) progenitors. We analyze the properties of the outflows at wide off-axis angles, produced by the expansion of the hot cocoon that surrounds the jet inside the progenitor star. We find that the cocoon emission at wide angles may have properties similar to those of the subclass of short-duration GRBs with persistent X-ray emission. We compute the predicted duration distribution, redshift distribution, and afterglow brightness, and we find that they are all in agreement with the observed properties of short GRBs with persistent emission. We suggest that a supernova component, the properties of the host galaxies, and late afterglow observations can be used as a crucial test to verify this model.