Improved WKB approximation for quantum tunneling: Application to heavy ion fusion

In this paper we revisit the one-dimensional tunneling problem. We consider Kemble's approximation for the transmission coefficient. We show how this approximation can be extended to above-barrier energies by performing the analytical continuation of the radial coordinate to the complex plane. We investigate the validity of this approximation by comparing their predictions for the cross section and for the barrier distribution with the corresponding quantum mechanical results. We find that the extended Kemble's approximation reproduces the results of quantum mechanics with great accuracy.Comment: 8 pages, 6 figures, in press, in European. Phys. Journal A (2017

Approximate transmission coefficients in heavy ion fusion

In this paper we revisit the one-dimensional tunnelling problem. We consider different approximations for the transmission through the Coulomb barrier in heavy ion collisions at near-barrier energies. First, we discuss approximations of the barrier shape by functional forms where the transmission coefficient is known analytically. Then, we consider Kemble's approximation for the transmission coefficient. We show how this approximation can be extended to above-barrier energies by performing the analytical continuation of the radial coordinate to the complex plane. We investigate the validity of the different approximations considered in this paper by comparing their predictions for transmission coefficients and cross sections of three heavy ion systems with the corresponding quantum mechanical results.Comment: 12 pages, 6 figure

Post-1995 French cinema: return of the social, return of the political?

A key trend in post-1995 French cinema has been the return of the social. Analysing this trend, this article seeks to evaluate its politic impact. Using Hervé Le Roux’s Reprise (1997) and Agnès Varda’s Les Glaneurs et la glaneuse (2000) as key meta-texts, it suggests that the current wave of politically engaged cinema needs to be approached in new ways that recognise how films trace the impact of a politically unmediated, ‘raw’ real on groups or individuals. It further suggests that the withdrawal of political mediation gives the films an essential ambiguity and a melodramatic quality that, rather than mere cliché, may be a privileged way to engage with the violence of the real. Film is now not so much in the van but dans le bain of a diverse socio-political stirring

Synthesis and biological activity of α-glucosyl C24:0 and C20:2 ceramides

a-Glucosyl ceramides 4 and 5 have been synthesised and evaluated for their ability to stimulate the activation and expansion of human iNKT cells. The key challenge in the synthesis of both target molecules was the stereoselective synthesis of the a-glycosidic linkage. Of the methods examined, glycosylation using per-TMS-protected glucosyl iodide 16 was completely a-selective and provided gram quantities of amine 11, from which a-glucosyl ceramides 4 and 5 were obtained by N-acylation. a-GlcCer 4, containing a C24 saturated acyl chain, stimulated a marked proliferation and expansion of human circulating iNKT cells in short-term cultures. a-GlcCer 5, which contains a C20 11,14-cis-diene acyl chain (C20:2),induced extremely similar levels of iNKT cell activation and expansion

Kawasaki-like multisystem inflammatory syndrome in children during the covid-19 pandemic in Paris, France: prospective observational study.

OBJECTIVES: To describe the characteristics of children and adolescents affected by an outbreak of Kawasaki-like multisystem inflammatory syndrome and to evaluate a potential temporal association with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. DESIGN: Prospective observational study. SETTING: General paediatric department of a university hospital in Paris, France. PARTICIPANTS: 21 children and adolescents (aged ≤18 years) with features of Kawasaki disease who were admitted to hospital between 27 April and 11 May 2020 and followed up until discharge by 15 May 2020. MAIN OUTCOME MEASURES: The primary outcomes were clinical and biological data, imaging and echocardiographic findings, treatment, and outcomes. Nasopharyngeal swabs were prospectively tested for SARS-CoV-2 using reverse transcription-polymerase chain reaction (RT-PCR) and blood samples were tested for IgG antibodies to the virus. RESULTS: 21 children and adolescents (median age 7.9 (range 3.7-16.6) years) were admitted with features of Kawasaki disease over a 15 day period, with 12 (57%) of African ancestry. 12 (57%) presented with Kawasaki disease shock syndrome and 16 (76%) with myocarditis. 17 (81%) required intensive care support. All 21 patients had noticeable gastrointestinal symptoms during the early stage of illness and high levels of inflammatory markers. 19 (90%) had evidence of recent SARS-CoV-2 infection (positive RT-PCR result in 8/21, positive IgG antibody detection in 19/21). All 21 patients received intravenous immunoglobulin and 10 (48%) also received corticosteroids. The clinical outcome was favourable in all patients. Moderate coronary artery dilations were detected in 5 (24%) of the patients during hospital stay. By 15 May 2020, after 8 (5-17) days of hospital stay, all patients were discharged home. CONCLUSIONS: The ongoing outbreak of Kawasaki-like multisystem inflammatory syndrome among children and adolescents in the Paris area might be related to SARS-CoV-2. In this study an unusually high proportion of the affected children and adolescents had gastrointestinal symptoms, Kawasaki disease shock syndrome, and were of African ancestry

Detecting the start of an influenza outbreak using exponentially weighted moving average charts

Background. Influenza viruses cause seasonal outbreaks in temperate climates, usually during winter and early spring, and are endemic in tropical climates. The severity and length of influenza outbreaks vary from year to year. Quick and reliable detection of the start of an outbreak is needed to promote public health measures. Methods. We propose the use of an exponentially weighted moving average (EWMA) control chart of laboratory confirmed influenza counts to detect the start and end of influenza outbreaks. Results. The chart is shown to provide timely signals in an example application with seven years of data from Victoria, Australia. Conclusions. The EWMA control chart could be applied in other applications to quickly detect influenza outbreaks

Challenges of keyword-based location disclosure

A practical solution to location privacy should be incremen-tally deployable. We claim it should hence reconcile the eco-nomic value of location to aggregators, usually ignored by prior works, with a user’s control over her information. Loca-tion information indeed is being collected and used by many mobile services to improve revenues, and this gives rise to a heated debate: Privacy advocates ask for stricter regula-tion on information collection, while companies argue that it would jeopardize the thriving economy of the mobile web. We describe a system that gives users control over their information and does not degrade the data given to aggre-gators. Recognizing that the first challenge is to express lo-cations in a way that is meaningful for advertisers and users, we propose a keyword based design. Keywords characterize locations, let the users inform the system about their sen-sitivity to disclosure, and build information directly usable by an advertiser’s targeting campaign. Our work makes two main contributions: we design a market of location infor-mation based on keywords and we analyze its robustness to attacks using data from ad-networks, geo-located services, and cell networks. Categories and Subject Descriptors Security and Privacy [Human and societal aspects of security and privacy]: Usability in security and privac

The effect of mission duration on LISA science objectives

The science objectives of the LISA mission have been defined under the implicit assumption of a 4-years continuous data stream. Based on the performance of LISA Pathfinder, it is now expected that LISA will have a duty cycle of ≈0.75 , which would reduce the effective span of usable data to 3 years. This paper reports the results of a study by the LISA Science Group, which was charged with assessing the additional science return of increasing the mission lifetime. We explore various observational scenarios to assess the impact of mission duration on the main science objectives of the mission. We find that the science investigations most affected by mission duration concern the search for seed black holes at cosmic dawn, as well as the study of stellar-origin black holes and of their formation channels via multi-band and multi-messenger observations. We conclude that an extension to 6 years of mission operations is recommended.publishedVersio

The social effects of entrepreneurship on society and some potential remedies: four provocations

A rapidly growing research stream examines the social effects of entrepreneurship on society. This research assesses the rise of entrepreneurship as a dominant theme in society and studies how entrepreneurship contributes to the production and acceptance of socio-economic inequality regimes, social problems, class and power struggles, and systemic inequities. In this article, scholars present new perspectives on an organizational sociology-inspired research agenda of entrepreneurial capitalism and detail the potential remedies to bound the unfettered expansion of a narrow conception of entrepreneurship. Taken together, the essays put forward four central provocations: 1) reform the study and pedagogy of entrepreneurship by bringing in the humanities; 2) examine entrepreneurship as a cultural phenomenon shaping society; 3) go beyond the dominant biases in entrepreneurship research and pedagogy; and 4) explore alternative models to entrepreneurial capitalism. More scholarly work scrutinizing the entrepreneurship–society nexus is urgently needed, and these essays provide generative arguments toward further developing this research agenda