Kinetic versus Magnetic Chaos in Toroidal Plasmas: A systematic quantitative comparison

Magnetic field line chaos occurs under the presence of non-axisymmetric perturbations of an axisymmetric equilibrium and is manifested by the destruction of smooth flux surfaces formed by the field lines. These perturbations also render the particle motion, as described by the guiding center dynamics, non-integrable and, therefore, chaotic. However, the chaoticities of the magnetic field lines and the particle orbits significantly differ both in strength and radial location in a toroidal configuration, except for the case of very low-energy particles whose orbits closely follow the magnetic field lines. The chaoticity of more energetic particles, undergoing large drifts with respect to the magnetic field lines, crucially determines the confinement properties of a toroidal device but cannot be inferred from that of the underlying magnetic field. In this work, we implement the Smaller ALignment Index (SALI) method for detecting and quantifying chaos, allowing for a systematic comparison between magnetic and kinetic chaos. The efficient quantification of chaos enables the assignment of a value characterizing the chaoticity of each orbit in the space of the three constants of the motion, namely energy, magnetic moment and toroidal momentum. The respective diagrams provide a unique overview of the different effects of a specific set of perturbations on the entire range of trapped and passing particles, as well as the radial location of the chaotic regions, offering a valuable tool for the study of particle energy and momentum transport and confinement properties of a toroidal fusion device.Comment: 27 pages, 7 figure

Evaluating multi-loop Feynman diagrams with infrared and threshold singularities numerically

We present a method to evaluate numerically Feynman diagrams directly from their Feynman parameters representation. We first disentangle overlapping singularities using sector decomposition. Threshold singularities are treated with an appropriate contour deformation. We have validated our technique comparing with recent analytic results for the gg->h two-loop amplitudes with heavy quarks and scalar quarks.Comment: 8 pages, 3 figures; references added, version to appear in JHE

Lipoprotein particles in patients with pediatric Cushing disease and possible cardiovascular risks.

BackgroundCardiovascular (CV) complications are the most significant cause of mortality in adults with Cushing disease (CD); little is known about CV risk factors in children with CD. Measurement of lipoprotein particles by nuclear magnetic resonance (NMR) spectroscopy is a novel technology to assess CV risk. The objective of the current study is to analyze the NMR lipid profile in pediatric CD patients before and 1 year after remission.MethodsNMR lipid profile was obtained via the Vantera NMR analyzer, using frozen serum samples from 33 CD patients (mean age 13.8 ± 4.0 years) evaluated between 1997 and 2017 at the National Institutes of Health (NIH) Clinical Center (CC).ResultsGlycA (glycosylated acute-phase proteins), triglyceride-rich particles (TRLP medium and very small sizes), low-density lipoprotein (LDL) particles (LDLP total and large size), high-density lipoprotein (HDL) particles (HDLP total, medium and small sizes), total cholesterol, LDL-cholesterol, HDL-cholesterol, GlycA inflammatory biomarker, and apolipoprotein B and apolipoprotein A1 (ApoA1) concentrations showed statistically significant changes after remission of CD (p < 0.05).ConclusionIn our study population, most of the lipid variables improved post-CD remission, with the exception of HDL and ApoA1, indicating that NMR lipoprotein profile may be a helpful tool in assessing the CV risk in pediatric patients with CD

Emotional labour in luxury hospitality: A comparative study between U.K. and Vietnamese hospitality workers

The growing attention on the understanding and employment of emotional labour in the luxury hospitality sector, is the result of a customer/market driven demand for service excellence and personalisation since the late 1990s. Emotional labour is the management of one’s emotions in order to achieve specific organisational outcomes (Van Dijk, et al. 2011); it can be performed by either faking emotions (‘surface acting’) or by managing felt emotions to be ‘authentic’ (deep acting) (Hochschild 1983). The existing research is largely based on the western context thus it is difficult to suggest that this concept can work the same way in a non-western context. This research aims to explore the mediating role of national culture on emotional labour; more specifically it investigates the similarities and differences in terms of emotional labour adoption, between hospitality workers in the U.K. and Vietnam. A survey questionnaire (both in electronic and hard copy form) has been distributed in approximately 200 hospitality workers located in both countries. The survey questionnaire design was based on the Dutch Questionnaire on Emotional Labour (D-QEL), a well-established tool used also in different contexts and occupational groups such as nurses and teachers (Näring et al. 2012). The two sets of responses (from the UK and Vietnam) are presented and analysed by the employment of quantitative methods (descriptive statistics). The data also incorporate a qualitative element; this refers to the part of the survey questionnaire where participants had the opportunity to share their opinions about emotional labour in their own cultural context. Building on Hofstede’s (1983, 2001) interpretation of cultural differences based on the national context, the findings suggest that both differences and similarities among hospitality employees in the UK and Vietnam. More specifically, the key differences are focused on the level of assertiveness, empathy, commitment and teamwork. On the other hand employees from both contexts are willing to undertake risks and to consider uncertainty as part of their everyday life. There are both conceptual and managerial implications of this study. On a conceptual level, there are indications that culture affects the adoption and exercise of emotional labour; as a result this can lead to either ‘surface’ or ‘deep’ acting, depending on the employees’ cultural background. On the other hand, luxury hospitality managers should customise their people management policies and procedures in order to attract and retain talented hospitality employees who can understand and exceed customer expectations

Numerical evaluation of loop integrals

We present a new method for the numerical evaluation of arbitrary loop integrals in dimensional regularization. We first derive Mellin-Barnes integral representations and apply an algorithmic technique, based on the Cauchy theorem, to extract the divergent parts in the epsilon->0 limit. We then perform an epsilon-expansion and evaluate the integral coefficients of the expansion numerically. The method yields stable results in physical kinematic regions avoiding intricate analytic continuations. It can also be applied to evaluate both scalar and tensor integrals without employing reduction methods. We demonstrate our method with specific examples of infrared divergent integrals with many kinematic scales, such as two-loop and three-loop box integrals and tensor integrals of rank six for the one-loop hexagon topology

Wildfire monitoring using satellite images, ontologies and linked geospatial data

Advances in remote sensing technologies have allowed us to send an ever-increasing number of satellites in orbit around Earth. As a result, Earth Observation data archives have been constantly increasing in size in the last few years, and have become a valuable source of data for many scientific and application domains. When Earth Observation data is coupled with other data sources many pioneering applications can be developed. In this paper we show how Earth Observation data, ontologies, and linked geospatial data can be combined for the development of a wildfire monitoring service that goes beyond applications currently deployed in various Earth Observation data centers. The service has been developed in the context of European project TELEIOS that faces the challenges of extracting knowledge from Earth Observation data head-on, capturing this knowledge by semantic annotation encoded using Earth Observation ontologies, and combining these annotations with linked geospatial data to allow the development of interesting applications

Economic zones for future complex power systems

This paper examines the economics of the electricity market out to 2050. We propose a flexible zoning concept, built up around economic and technical layers, in networks of the order of hundreds of thousands or millions of nodes. The Economic Layer runs auctions to determine the electricity to be delivered and prices. The Economic Layer delivers suggestions after a fixed ordering, starting with suppliers and demands that generates the lowest overall system cost, then second-lowest overall network cost etc. These suggestions are delivered to the Technical Layer that checks for feasibility in terms of technical constraints. The first match between the ranked suggestions and non-violation of technical constraints is chosen. We demonstrate why this paper should be considered for future power systems. This paper extends previous work on reactive power exchange by introducing market considerations in zoning mechanisms for active power exchanges. We are also exhibit the potential for much higher price resolution in distribution networks via our concept of economic zoning

Duration of Perioperative Antibiotic Prophylaxis in Open Fractures:A Systematic Review and Critical Appraisal

Fracture-related infection (FRI) remains a serious complication in open fracture care. Adequate surgical treatment and perioperative antibiotic prophylaxis (PAP) are key factors influencing the outcome. However, data concerning the optimal duration of PAP is scarce. The aim of this systematic review was to provide an overview of current evidence on the association between PAP duration and FRI in open fractures. A comprehensive search on 13 January 2022, in Embase, Medline, Cochrane, Web of Science and Google Scholar revealed six articles. Most studies compared either 1 day versus 5 days of PAP or included a cut-off at 72 h. Although prolonged PAP was not beneficial in the majority of patients, the variety of antibiotic regimens, short follow-up periods and unclear description of outcome parameters were important limitations that were encountered in most studies. This systematic review demonstrates a lack of well-constructed studies investigating the effect of PAP duration on FRI. Based on the available studies, prolonged PAP does not appear to be beneficial in the prevention of FRI in open fractures. However, these results should be interpreted with caution since all included studies had limitations. Future randomized trials are necessary to answer this research question definitively