56 research outputs found

    The status of the energy calibration, polarization and monochromatization of the FCC-ee

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    The Future Circular electron-positron Collider, FCC- ee, is designed for unprecedented precision for particle physics experiments from the Z-pole up to above the top-pair-threshold, corresponding to a beam energy range from 45.6 to 182.5 GeV. Performing collisions at various particle-physics resonances requires precise knowledge of the centre-of-mass energy (ECM) and collision boosts at all four interaction points. Measurement of the ECM by resonant depolarization of transversely polarized pilot bunches in combination with a 3D polarimeter, aims to achieve a systematic uncertainty of 4 and 100 keV for the Z-pole and W-pair-threshold energies respectively. The ECM itself depends on the RF-cavity locations, beamstrahlung, longitudinal impedance, the Earth’s tides, opposite sign dispersion and possible collision offsets. Application of monochromatization schemes are envisaged at certain beam energies to reduce the energy spread. The latest results of studies of the energy calibration, polarization and monochromatization are reported here

    The Compact Linear Collider (CLIC) - 2018 Summary Report

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    The Compact Linear Collider (CLIC) - 2018 Summary Report

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    The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear e+ee^+e^- collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years

    Extension of a SIR model for modelling the propagation of Covid-19 in several countries.

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    Background Several epidemiologic models have been published to forecast the spread of the COVID-19 pandemic yet there are still uncertainties regarding their accuracy. We report the main features of the development of a novel freely accessible model intended to urgently help researchers and decision makers to predict the evolution of the pandemic in their country. Methods and findings We built a SIR-type compartmental model with additional compartments and features. We made the hypothesis that the number of contagious individuals in the population was negligible as compared to the population size. We introduced a compartment D corresponding to the deceased patients and a compartment L representing the group of individuals who will die but who will not infect anybody (due to social or medical isolation). Our model integrated a time-dependent transmission rate, whose variations can be thought to be related to the public measures taken by each country and a cosine function to incorporate a periodic weekly component linked to the way in which numbers of cases and deaths are counted and reported, which can change from day to day. The model was able to accurately capture the different changes in the dynamics of the pandemic for nine different countries whatever the type of pandemic spread or containment measures. The model provided very accurate forecasts in the relatively short term (10 days). Conclusions In early evaluation of the performance of our model, we found a high level of accuracy between prediction and observed data, regardless of the country. The model should be used by the community to help public health decisions as we will refine it over time and further investigate its performance

    Health as an independent predictor of the 2017 French presidential voting behaviour: a cross-sectional analysis

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    International audienceBACKGROUND : It has been suggested that poor health has influenced vote for Brexit and the US presidential election. No such research has been published regarding the 2017 French presidential election.METHODS : We performed a cross-sectional analysis using a comprehensive set of socioeconomic and health indicators, to be compared with voting outcome at the first round of the 2017 French presidential election. The 95 French departments were selected as the unit of analysis. Data were obtained from publicly available sources. The linear model was used for both univariate and multivariate analysis to investigate the relation between voting patterns and predictors. Sensitivity analyses were done using the elastic-net regularisation.RESULTS : Emmanuel Macron and Marine Le Pen arrived ahead. When projected on the first factorial plane (~ 60% of the total inertia), Emmanuel Macron and Marine Le Pen tended to be in opposite directions regarding both socioeconomic and health factors. In the respective multivariate analyses of the two candidates, both socio-economic and health variables were significantly associated with voting patterns, with wealthier and healthier departments more likely to vote for Emmanuel Macron, and opposite departments more likely to vote for Marine Le Pen. Mortality (p = 0.03), severe chronic conditions (p = 0.014), and diabetes mellitus (p < 0.0001) were among the strongest predictors of voting pattern for Marine Le Pen. Sensitivity analyses did not substantially change those findings.CONCLUSIONS : We found that areas associated with poorer health status were significantly more likely to vote for the far-right candidate at the French presidential election, even after adjustment on socioeconomic criteria

    Evaluation of the SafeHeal Colovac+ anastomosis protection device : a preclinical study

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    Background The protective ostomy is the current standard of care to protect a low colorectal anastomosis from leakage, but exposes patients to complications requiring an alternative strategy. The Colovac+ is a vacuum-based intraluminal bypass device designed to shield the anastomosis from fecal content, preventing the clinical outcomes of anastomotic leakage. The objective of this study was to evaluate the preliminary efficacy, safety, and technical feasibility of the Colovac+ in a porcine model. Methods: Twelve pigs received a colorectal anastomosis with Colovac+ implantation. The device was left in situ for 10 days and then retrieved endoscopically. Six pigs were to be sacrificed immediately after device retrieval and the other 6 were to be sacrificed on day 38. Clinical, endoscopic, and histopathological examinations were performed to evaluate the following endpoints: prevention of contact between the anastomosis and fecal content, device migration, feasibility of the implantation and retrieval procedure, collateral damage to the colonic wall, colon healing after device retrieval, and systemic toxicity related to the device. Results: Eleven pigs completed the study. One pig died prematurely due to a surgical complication unrelated to the device (bladder damage with uroperitoneum). There was no evidence of contact between the anastomosis and fecal content, none of the pigs developed symptomatic anastomotic leakage, there were no significant device migrations, and there was no evidence of systemic toxicity. Colovac+ implantation was easily performed in all cases except 1 (due to an inappropriate lubricant). Colovac+ retrieval was achieved successfully in all cases. Postretrieval examinations on day 10 revealed ulcerations at the anchoring site in 4 cases indicating mechanical damage caused by the stent. However, in the recovery group, no ulcerations were observed on day 38, and the colonic wall had properly healed in all animals. Conclusions: The Colovac+ is a technically feasible, safe, and efficient device for the protection of a colorectal anastomosis in a porcine model. The device holds promise for clinical use and warrants further research
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