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Search for nuclear modifications of B meson production in pPb collisions at = 8.16 TeV
No full textInternational audienceNuclear medium effects on B meson production are studied using the binary-collision scaled cross section ratio between events of different multiplicities from proton-lead collisions. Data, collected by the CMS experiment in 2016 at a nucleon-nucleon center-of-mass energy of = 8.16 TeV, corresponding to an integrated luminosity of 175 nb, were used. The scaling factors in the ratio are determined using a novel approach based on the Z cross sections measured in the same events. The scaled ratio for B is consistent with unity for all event multiplicities, putting stringent constraints on nuclear modification for heavy flavor
Experimental study on the effect of an ionic liquid as anti-crystallization additive in a bi-adiabatic H2O-LiBr absorption chiller prototype
No full textInternational audienceAbsorption chillers are attractive because they use natural refrigerants and can be powered by low-grade heat sources. Among the commercially available working fluids, the most common one, H2O-LiBr, has a critical drawback associated with the crystallization of the solution at low temperatures and high absorbent concentrations. This limitation restricts the operating range of these systems, especially when they are air-cooled or used as heat pumps. Additives can be used in H2O-LiBr to reduce the crystallization temperature by improving the solubility of LiBr in the solution. However, they often present disadvantages such as the requirement of a rectifier, and a negative impact on heat and mass transfer. Ionic Liquids (ILs) used as additives represent an alternative to overcome these drawbacks. In the present study, 6 % of [DMIM][Cl] by mass in absorbent (LiBr + [DMIM][Cl]) is added as an anti-crystallization additive to study its effect on the experimental behavior and crystallization limit of a H2O-LiBr single-effect bi-adiabatic absorption chiller prototype. Results of H2O-LiBr and H2O–(LiBr + [DMIM][Cl]) were compared for the individual heat transfer elements and the global system COP. The results show a decrease in the crystallization temperature using H2O–(LiBr + [DMIM][Cl]), which extended the operating range of the prototype. A decrease of 15 ◦C in crystallization temperature was found for H2O–(LiBr + [DMIM][Cl]) compared to H2O-LiBr at an absorbent mass of 65 %. Crystallization impeded the operation for H2O-LiBr at the highest driving temperature (100 ◦C) and lowest cold source inlet temperature (9 ◦C), whereas no crystallization was observed at same operating conditions for the (LiBr + [DMIM][Cl]) solution. Under the tested conditions, the addition of the IL as additive increased the chiller operating range without the requirement of a rectifier and with a negligible impact on the cooling capacity and thermal COP
Bivariate P -and Q-polynomial structures of the association schemes based on attenuated spaces
No full textInternational audienceThe bivariate P -and Q-polynomial structures of association schemes based on attenuated spaces are examined using recurrence and difference relations of the bivariate polynomials which form the eigenvalues of the scheme. These bispectral properties are obtained from contiguity relations of univariate dual q-Hahn and affine q-Krawtchouk polynomials. The bispectral algebra associated to the bivariate polynomials is investigated, as well as the subconstituent algebra of the schemes. The properties of the schemes are compared to those of the non-binary Johnson schemes through a limit
Network-Based Molecular Descriptors for Protein Dynamics and Allosteric Regulation
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Est-ce que l'H<sub>2</sub> naturel peut être considéré comme renouvelable? Le cas de référence d'un aquifère profond dans un bassin sédimentaire intra-cratonique
No full textInternational audienceThe possibility that natural H2, or ‘white H2’, can be of economic interest relies on (1) the occurrence of large H2 gas accumulations similar in size to oil and gas fields and/or on (2) natural H2 production processes that are sufficiently efficient, locally, to lead to recharge rates that are commensurable with economical extraction rates. This latter possibility is investigated in the reference case of a deep aquifer located in an intracratonic sedimentary basin. Various production reactions are considered which involve RedOx reactions among Fe-bearing rock-forming minerals. The production kinetics of radiolytic H2 as a function of depth is also modeled. H2 consumption by microbial activity is implemented. It appears that olivine serpentinisation is the only process capable of generating H2 concentrations high enough to reach H2 gas saturation in the aquifer and thus generate H2-rich gas accumulation. The combination of a deep H2 source (> 7,000 m, i.e., T> 240°C) and a shallow accumulation (< few hundred meters) turns out to be the only possible configuration for such an accumulation. Estimated H2 accumulation rates do not however exceed a few tons of H2 per year, which is far from being an economical value estimated to a few kton per year at least. In conclusion, in the case of a deep aquifer in an intracratonic setting and considering water-rock interactions as the main source process, natural H2 can hardly be considered renewable on an industrial timescale
Does the use of shortened stems reduce early femoral complications in total hip arthroplasty using the direct anterior approach?
No full textInternational audienceAbstract Introduction The choice of femoral stem design during total hip arthroplasty (THA) through the Direct Anterior Approach (DAA) is critical. Shortened stems offer potential benefits such as bone preservation and reduced stress shielding. This study aimed to compare early complications at one year of follow-up between shortened and standard stems in DAA THA. Methods A retrospective monocentric case–control study included patients undergoing DAA THA from 2013 to 2023. Two cohorts were analyzed: 537 THA with standard stems and 346 THA with shortened stems. Three hundred forty-three patients in each group were matched (1:1) based on age, sex, and Body Mass Index (BMI). Two independent observers assessed femoral complications at one year. Femoral stem positioning was measured. Results The mean follow-up was 12 ± 0.5 months. The mean age was 64.1 ± 11.7 years. The mean BMI was 26.4 ± 4.4 kg/m 2 . Shortened stems showed a significantly lower rate of femoral complications (1.4% vs. 5.5%, P = 0.005), particularly for the GT fractures ( P = 0.006). In the shortened group, stem alignment was neutral in 69% of cases, varus in 27%, and valgus in 4%. Conclusion Shortened stems in DAA THA were associated with a lower rate of femoral complications, particularly fewer GT fractures. Although shortened stems were more often positioned in varus, this did not impact short-term complication rates. Trial Registration The Advisory Committee on Research Information Processing in the Field of Health (CCTIRS) approved this study on June 4, 2015 (Study ID 15–430)
Updated measurement of violation and polarisation in decays
No full textInternational audienceA time-integrated angular analysis of the decay , with and , is presented. The analysis employs a sample of proton-proton collision data collected by the LHCb experiment during 2015-2018 at a centre-of-mass energy of , corresponding to an integrated luminosity of . A simultaneous maximum-likelihood fit is performed to the angular distributions in bins of the mass. This fit yields measurements of the -averaged polarisation fractions and asymmetries for the P-wave component of the system. The longitudinal and parallel polarisation fractions are determined to be and , respectively, where the first uncertainty is statistical and the second is systematic. The asymmetries are measured with - precision and are found to be consistent with zero. These measurements, along with an updated determination of the branching fraction relative to the decay, are combined with previous LHCb results, providing the most precise values for these observables to date
Functional alignment in robotic total knee arthroplasty achieves comparable outcomes in varus and valgus knees despite distinct intraoperative strategies: Analysis of 355 consecutive cases
No full textInternational audienceAbstract Purpose Functional alignment (FA) optimises implant positioning based on patient‐specific anatomy, but data on intraoperative adjustments in varus and valgus knees remain limited. This study evaluates the impact of preoperative coronal alignment on implant positioning, bone resections, functional outcomes, and revision rates in robotic‐assisted total knee arthroplasty (TKA) under FA principles. Methods A retrospective analysis of 355 robotic‐assisted TKAs performed with FA was conducted. Patients were classified as varus ( n = 294, HKA < 180°) or valgus ( n = 61, HKA ≥ 180°). Intraoperative implant positioning, bone resections, and alignment parameters were recorded. Functional outcomes were assessed using the Knee Society Scores, Forgotten Joint Score, and Kujala score. Implant survivorship was analysed using the Kaplan–Meier method. Results Varus knees required greater tibial varus positioning (3.5° varus [interquartile range [IQR] 2–5] vs. 1° varus [IQR 0–2.5], p < 0.0001), while valgus knees required increased femoral valgus positioning (1.5° [IQR 0.38–2.5] vs. 0.7° [IQR −0.5 to 1.83], p = 0.0004). Bone resections also differed significantly between groups. Specifically, the valgus group had lower lateral tibial ( p = 0.0001), distal lateral ( p < 0.0001), and posterior lateral femoral resections ( p < 0.0001), but higher distal medial femoral resections ( p = 0.04). Postoperative functional outcomes were comparable across groups. Survival rates were 98.64% (varus) and 98.36% (valgus) ( p = 0.86), with a hazard ratio of 1.23 (95% CI: 0.12–12.57) for valgus knees. Conclusion This study systematically evaluates intraoperative modifications in FA‐based robotic TKA for varus and valgus knees. Despite distinct balancing strategies, both groups achieved comparable outcomes and implant survivorship. Level of Evidence Level III
