7,642 research outputs found

    Use of ‘Elf Bar’ among youth and young adults who currently vape in England:cross-sectional associations with demographics, dependence indicators and reasons for use

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    Background and aims: Elf Bar is currently the leading e-cigarette (vape) brand in Great Britain. This study examined youth and young adults’ use of Elf Bar, socio-demographic characteristics and dependence indicators and reasons for use over other brands. Design: Cross-sectional survey. Setting and participants: Online 2022 International Tobacco Control Project Youth Tobacco and Vaping Survey (N = 1355 16-29-year-olds in England who had vaped in the past 30 days). Measurements: Currently using Elf Bar most often (versus other brands) and associations with: socio-demographics, owning a vaping device, dependence indicators and reasons for brand choice. Logistic regressions were used. Findings: Among 16–29-year-olds who vaped in the past 30 days, 48.4% (n = 732) reported Elf Bar as the brand they used most often. Among 16–17-year-olds, 40.7% used Elf Bar over other brands; this was lower than among 18–19-year-olds (60.1%) and 20–29-year-olds (47.4%) (P ≤ 0.002). Using Elf Bar over other brands was higher among those who were female (55.2 versus 41.5% male), identified as White (53.1 versus 30.9% other/mixed), a student (54.5 versus 44.3% not), did not own a vape (66.7 versus 44.4% who did) and typically vaped 5–8 hours after waking (62.7 versus 36.8% within 5 min) (P ≤ 0.044). Most who vaped but had never smoked used Elf Bar (64.3%), although use did not significantly differ from those who currently (45.4%), formerly (42.3%) or experimentally (48.7%) smoked (all P ≥ 0.060). Popular reasons for choosing Elf Bar over other brands were better flavour/taste (47.5%), less expensive (28.7%), easier to get (26.1%), smoother to inhale (24.0%) and popularity (23.1%). ‘Better for quitting smoking’ (10.1%) was least frequently selected reason for choosing Elf Bar over other brands. Conclusions: Elf Bar brand e-cigarettes were used by approximately half of 16–29-year-olds who vaped in England in 2022 and was mainly chosen over other brands for subjective responses (e.g. flavour/taste), rather than for quitting smoking.</p

    Jost Function for Coupled Partial Waves

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    An exact method for direct calculation of the Jost functions and Jost solutions for non-central potentials which couple partial waves of different angular momenta is presented. A combination of the variable-constant method with the complex coordinate rotation is used to replace the matrix Schr\"odinger equation by an equivalent system of linear first--order differential equations. Solving these equations numerically, the Jost functions can be obtained to any desired accuracy for all complex momenta of physical interest, including the spectral points corresponding to bound and resonant states. The effectiveness of the method is demonstrated using the Reid soft-core and Moscow nucleon-nucleon potentials which involve tensor forces.Comment: 32 pages, RevTex, only latex pseudo-figure

    Global aspects of the space of 6D N = 1 supergravities

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    We perform a global analysis of the space of consistent 6D quantum gravity theories with N = 1 supersymmetry, including models with multiple tensor multiplets. We prove that for theories with fewer than T = 9 tensor multiplets, a finite number of distinct gauge groups and matter content are possible. We find infinite families of field combinations satisfying anomaly cancellation and admitting physical gauge kinetic terms for T > 8. We find an integral lattice associated with each apparently-consistent supergravity theory; this lattice is determined by the form of the anomaly polynomial. For models which can be realized in F-theory, this anomaly lattice is related to the intersection form on the base of the F-theory elliptic fibration. The condition that a supergravity model have an F-theory realization imposes constraints which can be expressed in terms of this lattice. The analysis of models which satisfy known low-energy consistency conditions and yet violate F-theory constraints suggests possible novel constraints on low-energy supergravity theories.Comment: 41 pages, 1 figur

    Advanced surface treatments for medium-velocity superconducting RF cavities for high accelerating gradient continuous-wave operation

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    Nitrogen-doping and furnace-baking are advanced high-Q0 recipes developed for 1.3 GHz TESLA-type cavities. These treatments will significantly benefit the high-Q0 linear accelerator community if they can be successfully adapted to different cavity styles and frequencies. Strong frequency- and geometry- dependence of these recipes makes the technology transfer amongst different cavity styles and frequencies far from straightforward, and requires rigorous study. Upcoming high-Q0 continuous-wave linear accelerator projects, such as the proposed Michigan State University Facility for Rare Isotope Beam Energy Upgrade, and the underway Fermilab's Proton Improvement Plan-II, could benefit enormously from adapting these techniques to their beta_opt = 0.6 ~650 MHz 5-cell elliptical superconducting rf cavities, operating at an accelerating gradient of around ~17 MV/m. This is the first investigation of the adaptation of nitrogen doping and medium temperature furnace baking to prototype 644 MHz beta_opt = 0.65 cavities, with the aim of demonstrating the high-Q0 potential of these recipes in these novel cavities for future optimization as part of the FRIB400 project R&D. We find that nitrogen-doping delivers superior Q0, despite the sub-GHz operating frequency of these cavities, but is sensitive to the post-doping electropolishing removal step and experiences elevated residual resistance. Medium temperature furnace baking delivers reasonable performance with decreased residual resistance compared to the nitrogen doped cavity, but may require further recipe refinement. The gradient requirement for the FRIB400 upgrade project is comfortably achieved by both recipes.Comment: 16 pages, 5 figure

    Health care professionals’ experience, understanding and perception of need of advanced cancer patients with cachexia and their families: The benefits of a dedicated clinic.

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    BACKGROUND: Cachexia is defined as the on-going loss of skeletal muscle mass that cannot be fully reversed by conventional nutritional support. It is found in up to 80% of patients with advanced cancer and has profound psycho-social consequences for patients and their families. Previous studies demonstrate that many healthcare professionals receive little formal education in cachexia management leading them to feel that they have limited understanding of the syndrome and cannot intervene effectively. This study aims to examine the value of a dedicated cachexia clinic and its influence on staff understanding and practice. METHODS: An exploratory qualitative study was conducted. The study employed semi-structured interviews with a range of healthcare professionals responsible for designing and delivering cancer care in a large teaching hospital in Australia. This hospital had a dedicated cachexia clinic. RESULTS: In-depth interviews were conducted with 8 healthcare professionals and senior managers. Four themes were identified: formal and informal education; knowledge and understanding; truth telling in cachexia and palliative care; and, a multi-disciplinary approach. Findings show that improved knowledge and understanding across a staff body can lead to enhanced staff confidence and a willingness to address cancer cachexia and its consequences with patients and their families. CONCLUSION: Comparisons with similar previous research demonstrate the advantages of providing a structure for staff to gain knowledge about cachexia and how this can contribute to feelings of improved understanding and confidence necessary to respond to the challenge of cachexia

    SKU classification: A literature review and conceptual framework

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    Purpose - Stock keeping unit (SKU) classifications are widely used in the field of production and operations management. Although many theoretical and practical examples of classifications exist, there are no overviews of the current literature, and general guidelines are lacking with respect to method selection for classifying SKUs. The purpose of this paper is to systematically synthesise the earlier work in this area, and to conceptualise and discuss the factors that influence the choice of a specific SKU classification. Design/methodology/approach - The paper structurally reviews existing contributions and synthesises these into a conceptual framework for SKU classification. Findings - How SKUs are classified depends on the classification aim, the context and the method that is chosen. In total, three main production and operations management aims were found: inventory management, forecasting and production strategy. Within the method three decisions are identified to come to a classification: the characteristics, the classification technique and the operationalisation of the classes. Research limitations/implications - Drawing on the literature survey, the authors conclude with a conceptual framework describing the factors that influence SKU classification. Further research could use this framework to develop guidelines for real-life applications. Practical implications Examples from a variety of industries and general directions are provided which managers could use to develop their own SKU classification. Originality/value - The paper aims to advance the literature on SKU classification from the level of individual examples to a conceptual level and provides directions on how to develop a SKU classification

    On the Hodge structure of elliptically fibered Calabi-Yau threefolds

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    The Hodge numbers of generic elliptically fibered Calabi-Yau threefolds over toric base surfaces fill out the "shield" structure previously identified by Kreuzer and Skarke. The connectivity structure of these spaces and bounds on the Hodge numbers are illuminated by considerations from F-theory and the minimal model program. In particular, there is a rigorous bound on the Hodge number h_{21} <= 491 for any elliptically fibered Calabi-Yau threefold. The threefolds with the largest known Hodge numbers are associated with a sequence of blow-ups of toric bases beginning with the Hirzebruch surface F_{12} and ending with the toric base for the F-theory model with largest known gauge group.Comment: 16 pages, 4 figures; v2: minor corrections, references added; v3: minor corrections, improvements, reference added, version for JHE

    Aspects of ALE Matrix Models and Twisted Matrix Strings

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    We examine several aspects of the formulation of M(atrix)-Theory on ALE spaces. We argue for the existence of massless vector multiplets in the resolved An1A_{n-1} spaces, as required by enhanced gauge symmetry in M-Theory, and that these states might have the correct gravitational interactions. We propose a matrix model which describes M-Theory on an ALE space in the presence of wrapped membranes. We also consider orbifold descriptions of matrix string theories, as well as more exotic orbifolds of these models, and present a classification of twisted matrix string theories according to Reid's exact sequences of surface quotient singularities.Comment: 27 pages LaTeX2e, 7 figures, using utarticle.cls (included), array.sty, amsmath.sty, amsfonts.sty, cite.sty, epsf.sty. Bibtex style: utphys.bst (.bbl file included). Section on wrapped membrane states revised and expanded. We now argue for the existence of wrapped membranes and propose a matrix model which describes M-Theory on an ALE space in the presence of wrapped membrane

    Mathematical modelling of polyamine metabolism in bloodstream-form trypanosoma brucei: An application to drug target identification

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    © 2013 Gu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedThis article has been made available through the Brunel Open Access Publishing Fund.We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT) and ornithine production (OrnPt) have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione) were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.The work was carried out under a PhD programme partly funded by Prof. Ray Welland, School of Computing Science, University of Glasgo
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