711 research outputs found
NLO Leptoquark Production and Decay: The Narrow-Width Approximation and Beyond
We study the leptoquark model of Buchm\"uller, R\"uckl and Wyler, focusing on
a particular type of scalar () and vector () leptoquark. The primary
aim is to perform the calculations for leptoquark production and decay at
next-to-leading order (NLO) to establish the importance of the NLO
contributions and, in particular, to determine how effective the
narrow-width-approximation (NWA) is at NLO. For both the scalar and vector
leptoquarks it is found that the NLO contributions are large, with the larger
corrections occurring for the case vector leptoquarks. For the scalar
leptoquark it is found that the NWA provides a good approximation for
determining the resonant peak, however the NWA is not as effective for the
vector leptoquark. For both the scalar and vector leptoquarks there are large
contributions away from the resonant peak, which are missing from the NWA
results, and these make a significant difference to the total cross-section.Comment: 22 pages, 17 figure
An Enhanced Nonlinear Critical Gradient for Electron Turbulent Transport due to Reversed Magnetic Shear
The first nonlinear gyrokinetic simulations of electron internal transport
barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed
magnetic shear can suppress thermal transport by increasing the nonlinear
critical gradient for electron-temperature-gradient-driven turbulence to three
times its linear critical value. An interesting feature of this turbulence is
nonlinearly driven off-midplane radial streamers. This work reinforces the
experimental observation that magnetic shear is likely an effective way of
triggering and sustaining e-ITBs in magnetic fusion devices.Comment: 4 pages, 5 figure
An Enhanced Nonlinear Critical Gradient for Electron Turbulent Transport due to Reversed Magnetic Shear
The first nonlinear gyrokinetic simulations of electron internal transport
barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed
magnetic shear can suppress thermal transport by increasing the nonlinear
critical gradient for electron-temperature-gradient-driven turbulence to three
times its linear critical value. An interesting feature of this turbulence is
nonlinearly driven off-midplane radial streamers. This work reinforces the
experimental observation that magnetic shear is likely an effective way of
triggering and sustaining e-ITBs in magnetic fusion devices.Comment: 4 pages, 5 figure
‘The Invisible Chain by Which All Are Bound to Each Other’: Civil Defence Magazines and the Development of Community During the Second World War
This article uses local collaboratively produced civil defence magazines to examine how community spirit was developed and represented within the civil defence services during the Second World War. It highlights the range of functions which the magazines performed, as well as the strategies employed by civil defence communities to manage their emotions in order to keep morale high and distract personnel from the fear and boredom experienced while on duty. The article also discusses silences in the magazines — especially around the experience of air raids — and argues that this too reflects group emotional management strategies. The significance of local social groups in developing narratives about civil defence and their workplace communities is demonstrated, and the article shows how personnel were able to engage with and refashion dominant cultural narratives of the ‘people’s war’ in order to assert their own status within the war effort
Visual adaptation alters the apparent speed of real-world actions
The apparent physical speed of an object in the field of view remains constant despite variations in retinal velocity due to viewing conditions (velocity constancy). For example, people and cars appear to move across the field of view at the same objective speed regardless of distance. In this study a series of experiments investigated the visual processes underpinning judgements of objective speed using an adaptation paradigm and video recordings of natural human locomotion. Viewing a video played in slow-motion for 30seconds caused participants to perceive subsequently viewed clips played at standard speed as too fast, so playback had to be slowed down in order for it to appear natural; conversely after viewing fast-forward videos for 30seconds, playback had to be speeded up in order to appear natural. The perceived speed of locomotion shifted towards the speed depicted in the adapting video (‘re-normalisation’). Results were qualitatively different from those obtained in previously reported studies of retinal velocity adaptation. Adapting videos that were scrambled to remove recognizable human figures or coherent motion caused significant, though smaller shifts in apparent locomotion speed, indicating that both low-level and high-level visual properties of the adapting stimulus contributed to the changes in apparent speed
17 ways to say yes:Toward nuanced tone of voice in AAC and speech technology
People with complex communication needs who use speech-generating devices have very little expressive control over their tone of voice. Despite its importance in human interaction, the issue of tone of voice remains all but absent from AAC research and development however. In this paper, we describe three interdisciplinary projects, past, present and future: The critical design collection Six Speaking Chairs has provoked deeper discussion and inspired a social model of tone of voice; the speculative concept Speech Hedge illustrates challenges and opportunities in designing more expressive user interfaces; the pilot project Tonetable could enable participatory research and seed a research network around tone of voice. We speculate that more radical interactions might expand frontiers of AAC and disrupt speech technology as a whole
A primary care, multi-disciplinary disease management program for opioid-treated patients with chronic non-cancer pain and a high burden of psychiatric comorbidity
BACKGROUND: Chronic non-cancer pain is a common problem that is often accompanied by psychiatric comorbidity and disability. The effectiveness of a multi-disciplinary pain management program was tested in a 3 month before and after trial. METHODS: Providers in an academic general medicine clinic referred patients with chronic non-cancer pain for participation in a program that combined the skills of internists, clinical pharmacists, and a psychiatrist. Patients were either receiving opioids or being considered for opioid therapy. The intervention consisted of structured clinical assessments, monthly follow-up, pain contracts, medication titration, and psychiatric consultation. Pain, mood, and function were assessed at baseline and 3 months using the Brief Pain Inventory (BPI), the Center for Epidemiological Studies-Depression Scale scale (CESD) and the Pain Disability Index (PDI). Patients were monitored for substance misuse. RESULTS: Eighty-five patients were enrolled. Mean age was 51 years, 60% were male, 78% were Caucasian, and 93% were receiving opioids. Baseline average pain was 6.5 on an 11 point scale. The average CESD score was 24.0, and the mean PDI score was 47.0. Sixty-three patients (73%) completed 3 month follow-up. Fifteen withdrew from the program after identification of substance misuse. Among those completing 3 month follow-up, the average pain score improved to 5.5 (p = 0.003). The mean PDI score improved to 39.3 (p < 0.001). Mean CESD score was reduced to 18.0 (p < 0.001), and the proportion of depressed patients fell from 79% to 54% (p = 0.003). Substance misuse was identified in 27 patients (32%). CONCLUSIONS: A primary care disease management program improved pain, depression, and disability scores over three months in a cohort of opioid-treated patients with chronic non-cancer pain. Substance misuse and depression were common, and many patients who had substance misuse identified left the program when they were no longer prescribed opioids. Effective care of patients with chronic pain should include rigorous assessment and treatment of these comorbid disorders and intensive efforts to insure follow up
On the Origin of Cosmic Magnetic Fields
We review the literature concerning how the cosmic magnetic fields pervading
nearly all galaxies actually got started. some observational evidence involves
the chemical abundance of the light elements Be and B, while another one is
based on strong magnetic fields seen in high red shift galaxies. Seed fields,
whose strength is of order 10^{-20} gauss, easily sprung up in the era
preceding galaxy formation. Several mechanisms are proposed to amplify these
seed fields to microgauss strengths. The standard mechanism is the Alpha-Omega
dynamo theory. It has a major difficulty that makes unlikely to provide the
sole origin. The difficulty is rooted in the fact that the total flux is
constant. This implies that flux must be removed from the galactic discs. This
requires that the field and flux be separated, for otherwise interstellar mass
must be removed from the deep galactic gravitational and then their strength
increased by the alpha omega theory.Comment: 90 pages and 6 figures; accepted for publication in Reports of
Progress in Physics as an invited revie
Moment Closure - A Brief Review
Moment closure methods appear in myriad scientific disciplines in the
modelling of complex systems. The goal is to achieve a closed form of a large,
usually even infinite, set of coupled differential (or difference) equations.
Each equation describes the evolution of one "moment", a suitable
coarse-grained quantity computable from the full state space. If the system is
too large for analytical and/or numerical methods, then one aims to reduce it
by finding a moment closure relation expressing "higher-order moments" in terms
of "lower-order moments". In this brief review, we focus on highlighting how
moment closure methods occur in different contexts. We also conjecture via a
geometric explanation why it has been difficult to rigorously justify many
moment closure approximations although they work very well in practice.Comment: short survey paper (max 20 pages) for a broad audience in
mathematics, physics, chemistry and quantitative biolog
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