2,177 research outputs found
Gauged W Algebras
We perform an Hamiltonian reduction on a classical \cw(\cg, \ch) algebra, and
prove that we get another \cw(\cg, \ch) algebra, with . In
the case \cg=S\ell(n), the existence of a suitable gauge, called Generalized
Horizontal Gauge, allows to relate in this way two \cw-algebras as soon as
their corresponding \ch-algebras are related by inclusion.Comment: 11 p., Latex. There was a misprint on the last autho
Reverse Shock Emission Revealed in Early Photometry in the Candidate Short GRB 180418A
We present observations of the possible short GRB 180418A in -rays,
X-rays, and in the optical. Early optical photometry with the TAROT and RATIR
instruments show a bright peak ( 14.2 AB mag) between and
seconds that we interpret as the signature of a reversal shock. Later
observations can be modeled by a standard forward shock model and show no
evidence of jet break, allowing us to constrain the jet collimation to
. Using deep late-time optical observations we place an
upper limit of AB mag on any underlying host galaxy. The detection of
the afterglow in the \textit{Swift} UV filters constrains the GRB redshift to
and places an upper bound on the -ray isotropic equivalent
energy erg.
The properties of this GRB (e.g. duration, hardness ratio, energetic, and
environment) lie at the intersection between short and long bursts, and we can
not conclusively identify its type. We estimate that the probability that it is
drawn from the population of short GRBs is 10\%-30\%.Comment: Accepted por publication in Ap
Pre-discovery observations of CoRoT-1b and CoRoT-2b with the BEST survey
The BEST wide-angle telescope installed at the Observatoire de Haute-Provence
and operated in remote control from Berlin by the Institut fuer
Planetenforschung, DLR, has observed the CoRoT target fields prior to the
mission. The resulting archive of stellar photometric lightcurves is used to
search for deep transit events announced during CoRoT's alarm-mode to aid in
fast photometric confirmation of these events. The "initial run" field of CoRoT
(IRa01) has been observed with BEST in November and December 2006 for 12
nights. The first "long run" field (LRc01) was observed from June to September
2005 for 35 nights. After standard CCD data reduction, aperture photometry has
been performed using the ISIS image subtraction method. About 30,000
lightcurves were obtained in each field. Transits of the first detected planets
by the CoRoT mission, CoRoT-1b and CoRoT-2b, were found in archived data of the
BEST survey and their lightcurves are presented here. Such detections provide
useful information at the early stage of the organization of follow-up
observations of satellite alarm-mode planet candidates. In addition, no period
change was found over ~4 years between the first BEST observation and last
available transit observations.Comment: AJ, accepte
Targeted treatment options for paediatric B-cell precursor acute lymphoblastic leukaemia patients with constitutional or somatic chromosome 21 alterations
Background: Chromosome 21 is affected in âŒ60% of paediatric B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) patients and includes somatic and constitutional gains, intrachromosomal amplification of chromosome 21 (iAMP21), and the translocation t(12;21) resulting in the ETV6::RUNX1 gene fusion. Methods: Since these numeric and structural chromosome 21 alterations are not targetable, we studied the type and frequency of yet-proven targetable events co-occurring with chromosome 21 alterations.Results: Among 307 primary paediatric BCP-ALL cases, JAK/STAT pathway lesions were most frequent in patients with constitutional gain of chromosome 21 (Down syndrome ALL; 35/71, 49%) and iAMP21 (9/22, 41%). RAS pathway lesions were most frequent in high hyperdiploidy (62/108, 57%) and FLT3 lesions were most frequent in iAMP21 (7/22, 32%). Virtually all cases expressed CD19 and CD22 at the cell surface. Positivity for CD20 surface expression ranged from 67% in iAMP21 (8/12) to 20% in ETV6::RUNX1 (26/129). Conclusion: Activated JAK/STAT, RAS or FLT3 signalling, and CD marker surface expression may provide targetable treatment options for the majority of chromosome 21-altered BCP-ALL cases.</p
Proenkephalin and risk of developing chronic kidney disease:The Prevention of Renal and Vascular End-stage Disease study
BACKGROUND: Proenkephalin (pro-ENK) was recently found to be associated with low estimated glomerular filtration rate (eGFR). The association of pro-ENK with urinary albumin excretion (UAE), another marker for chronic kidney disease (CKD), has not been investigated. We examined the association of pro-ENK with eGFR and UAE as markers of CKD. METHODS: We included 4375 subjects of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study. CKDeGFR was defined as development of eGFRâ<60âml/min/1.73 m2 and CKDUAE as albuminuriaâ>30âmg/24âh. RESULTS: Baseline median pro-ENK was 52.2 (IQR: 44.9-60.5) pmol/L. After a median follow-up of 8.4 (IQR: 7.9-8.9) years, 183 subjects developed CKDeGFR and 371 developed CKDUAE. The association of pro-ENK with CKDeGFR was modified by sex (Pinteractionâ<â0.1), in such a way that after adjustment, the association only remained significant in men (adjusted hazard ratio per SD increase in 10log-transformed pro-ENK, 1.65; 95% CI: 1.15-2.36) and not in women (0.83; 0.58-1.20). No significant association was observed between pro-ENK and CKDUAE risk (0.83; 0.58-1.20). CONCLUSIONS: High pro-ENK is associated with increased risk of CKDeGFR in men, but not in women. No association of pro-ENK with CKDUAE was observed. These results should be interpreted with caution, since residual confounding and potential overfitting of models could have influenced the results
Fuel performance simulations of ESNII prototypes: Results on the MYRRHA case study
Nominal and transient conditions of the ESNII prototypes were investigated in the INSPYRE Project using the European fuel performance codes GERMINAL, MACROS and TRANSURANUS. This Deliverable presents the results of the simulations of the MYRRHA case study: MYRRHA nominal irradiation conditions and the occurrence of a beam power jump (overâpower) transient at the beginning and end of life of the fuel pin in reactor. Besides the application of the reference (âpreâINSPYREâ) code versions, the activity involves the evaluation of the impact of the improved models of MOX fuel properties developed in INSPYRE and implemented in the three fuel performance codes. These modelling advances concern the thermal properties (thermal conductivity, melting temperature), mechanical properties (thermal expansion, Youngâs modulus) and the mechanistic treatment of fission gas behaviour and release from MOX fuels.
The results yielded by the preâINSPYRE and postâINSPYRE versions of the codes involved are presented and assessed in terms of evolution in time, as well as axial and radial profiles of significant quantities, both integral and local. Then, the code results are compared with the design limits set for the MYRRHA fuel pins, in particular the maximal fuel temperature admitted, which prevents fuel melting, and the maximal allowed cladding plasticity that ensures the cladding integrity. The outcome is a complete compliance of the pin behaviour with the design limits, respecting adequate margins even in the case of the hottest fuel pin and in the case of beam power jump transients
Results of the benchmark between pre- and post-INSPYRE code versions on selected experimental cases
This report presents the results of the simulation of the SUPERFACT-1, RAPSODIE-I and NESTOR-3 irradiation experiments using the fuel performance codes TRANSURANUS, MACROS, GERMINAL. The simulations aim at the evaluation of the code improvements made during the INSPYRE project. The comparison of the integral pin performance results with experimental measurements available from the irradiation experiments considered and the comparison between the code results are presented. Both the results obtained using the âpre-INSPYREâ code versions and the improved âpost-INSPYREâ ones, in which novel data and models originating from other Work Packages of the INSPYRE Project were implemented, are provided
Assessment of INSPYRE-extended fuel performance codes against the SUPERFACT-1 fast reactor irradiation experiment
Design and safety assessment of fuel pins for application in innovative Generation IV fast reactors calls for a dedicated nuclear fuel modelling and for the extension of the fuel performance code capabilities to the envisaged materials and irradiation conditions. In the INSPYRE Project, comprehensive and physics- based models for the thermal-mechanical properties of UePu mixed-oxide (MOX) fuels and for fission gas behaviour were developed and implemented in the European fuel performance codes GERMINAL, MACROS and TRANSURANUS. As a follow-up to the assessment of the reference code versions (âpre- INSPYREâ, NET 53 (2021) 3367e3378), this work presents the integral validation and benchmark of the code versions extended in INSPYRE (âpost-INSPYREâ) against two pins from the SUPERFACT-1 fast reactor irradiation experiment. The post-INSPYRE simulation results are compared to the available integral and local data from post-irradiation examinations, and benchmarked on the evolution during irradiation of quantities of engineering interest (e.g., fuel central temperature, fission gas release). The comparison with the pre-INSPYRE results is reported to evaluate the impact of the novel models on the predicted pin performance. The outcome represents a step forward towards the description of fuel behaviour in fast reactor irradiation conditions, and allows the identification of the main remaining gaps
Driving pressure during general anesthesia for open abdominal surgery (DESIGNATION) : study protocol of a randomized clinical trial
Background
Intraoperative driving pressure (Delta P) is associated with development of postoperative pulmonary complications (PPC). When tidal volume (V-T) is kept constant, Delta P may change according to positive end-expiratory pressure (PEEP)-induced changes in lung aeration. Delta P may decrease if PEEP leads to a recruitment of collapsed lung tissue but will increase if PEEP mainly causes pulmonary overdistension. This study tests the hypothesis that individualized high PEEP, when compared to fixed low PEEP, protects against PPC in patients undergoing open abdominal surgery.
Methods
The "Driving prESsure durIng GeNeral AnesThesIa for Open abdomiNal surgery trial" (DESIGNATION) is an international, multicenter, two-group, double-blind randomized clinical superiority trial. A total of 1468 patients will be randomly assigned to one of the two intraoperative ventilation strategies. Investigators screen patients aged >= 18 years and with a body mass index <= 40 kg/m(2), scheduled for open abdominal surgery and at risk for PPC. Patients either receive an intraoperative ventilation strategy with individualized high PEEP with recruitment maneuvers (RM) ("individualized high PEEP") or one in which PEEP of 5 cm H2O without RM is used ("low PEEP"). In the "individualized high PEEP" group, PEEP is set at the level at which Delta P is lowest. In both groups of the trial, V-T is kept at 8 mL/kg predicted body weight. The primary endpoint is the occurrence of PPC, recorded as a collapsed composite of adverse pulmonary events. Discussion DESIGNATION will be the first randomized clinical trial that is adequately powered to compare the effects of individualized high PEEP with RM versus fixed low PEEP without RM on the occurrence of PPC after open abdominal surgery. The results of DESIGNATION will support anesthesiologists in their decisions regarding PEEP settings during open abdominal surgery
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Hemoglobin A1c and Arterial and Ventricular Stiffness in Older Adults
Objective: Arterial and ventricular stiffening are characteristics of diabetes and aging which confer significant morbidity and mortality; advanced glycation endproducts (AGE) are implicated in this stiffening pathophysiology. We examined the association between HbA1c, an AGE, with arterial and ventricular stiffness measures in older individuals without diabetes. Research Design & Methods: Baseline HbA1c was measured in 830 participants free of diabetes defined by fasting glucose or medication use in the Cardiovascular Health Study, a population-based cohort study of adults aged â„65 years. We performed cross-sectional analyses using baseline exam data including echocardiography, ankle and brachial blood pressure measurement, and carotid ultrasonography. We examined the adjusted associations between HbA1c and multiple arterial and ventricular stiffness measures by linear regression models and compared these results to the association of fasting glucose (FG) with like measures. Results: HbA1c was correlated with fasting and 2-hour postload glucose levels (r = 0.21; p<0.001 for both) and positively associated with greater body-mass index and black race. In adjusted models, HbA1c was not associated with any measure of arterial or ventricular stiffness, including pulse pressure (PP), carotid intima-media thickness, ankle-brachial index, end-arterial elastance, or left ventricular mass (LVM). FG levels were positively associated with systolic, diastolic and PP and LVM. Conclusions: In this sample of older adults without diabetes, HbA1c was not associated with arterial or ventricular stiffness measures, whereas FG levels were. The role of AGE in arterial and ventricular stiffness in older adults may be better assessed using alternate AGE markers
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