215 research outputs found
Commissioning of the vacuum system of the KATRIN Main Spectrometer
The KATRIN experiment will probe the neutrino mass by measuring the
beta-electron energy spectrum near the endpoint of tritium beta-decay. An
integral energy analysis will be performed by an electro-static spectrometer
(Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a
volume of 1240 m^3, and a complex inner electrode system with about 120000
individual parts. The strong magnetic field that guides the beta-electrons is
provided by super-conducting solenoids at both ends of the spectrometer. Its
influence on turbo-molecular pumps and vacuum gauges had to be considered. A
system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter
strips has been deployed and was tested during the commissioning of the
spectrometer. In this paper the configuration, the commissioning with bake-out
at 300{\deg}C, and the performance of this system are presented in detail. The
vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is
demonstrated that the performance of the system is already close to these
stringent functional requirements for the KATRIN experiment, which will start
at the end of 2016.Comment: submitted for publication in JINST, 39 pages, 15 figure
Lady Gaga as (dis)simulacrum of monstrosity
Lady Gaga’s celebrity DNA revolves around the notion of monstrosity, an extensively
researched concept in postmodern cultural studies. The analysis that is offered in this
paper is largely informed by Deleuze and Guattari’s notion of monstrosity, as well as
by their approach to the study of sign-systems that was deployed in A Thousand
Plateaus. By drawing on biographical and archival visual data, with a focus on the
relatively underexplored live show, an elucidation is afforded of what is really monstrous
about Lady Gaga. The main argument put forward is that monstrosity as sign
seeks to appropriate the horizon of unlimited semiosis as radical alterity and openness
to signifying possibilities. In this context it is held that Gaga effectively delimits her
unique semioscape; however, any claims to monstrosity are undercut by the inherent
limits of a representationalist approach in sufficiently engulfing this concept. Gaga is
monstrous for her community insofar as she demands of her fans to project their
semiosic horizon onto her as a simulacrum of infinite semiosis. However, this simulacrum
may only be evinced in a feigned manner as a (dis)simulacrum. The analysis of
imagery from seminal live shows during 2011–2012 shows that Gaga’s presumed
monstrosity is more akin to hyperdifferentiation as simultaneous employment of
heterogeneous and potentially dissonant inter pares cultural representations. The article
concludes with a problematisation of audience effects in the light of Gaga’s adoption of
a schematic and post-representationalist strategy in the event of her strategy’s emulation
by competitive artists
Patient Perspectives of an Intensive Comprehensive Aphasia Program for Stroke Survivors
Introduction: Persons with aphasia (PWA) who participate in intensive comprehensive poststroke language rehabilitation programs make a variety of significant investments. While intensive aphasia programs and intensive comprehensive aphasia programs (ICAPs) are becoming increasingly prevalent across health care settings, patient perspectives of ICAPs have not been explored. The purpose of this qualitative study was to examine patient perspectives about the experience of participating in an ICAP at the University of Montana. The primary research question of this study was: “what is it like to be a PWA in an ICAP?” Methods: Researchers used an interpretive phenomenological approach to conduct nine structured interviews from PWAs who described their lived experiences in the ICAP. All interviews were audiovisually recorded and transcribed from the video recordings. Analysis involved an iterative and collaborative coding process. Transcripts were coded and themes were developed from the PWAs’ shared perspectives. Results: Three primary themes emerged from patient perspectives including: (1) experience with each of the ICAP components is generally positive, (2) we notice the impact of the ICAP on our communication, and (3) relationships with people in the ICAP are important. Discussion: Results support emerging evidence that ICAPs can be a positive experience for PWA due to the perceptible impact on communication improvement and frequent and varied opportunities to interact with others. ICAPs may be a worthwhile investment for PWA, thereby contributing to the cost-benefit utility and implementation feasibility of the service delivery model
Solving a Coupled Set of Truncated QCD Dyson-Schwinger Equations
Truncated Dyson-Schwinger equations represent finite subsets of the equations
of motion for Green's functions. Solutions to these non-linear integral
equations can account for non-perturbative correlations. A closed set of
coupled Dyson-Schwinger equations for the propagators of gluons and ghosts in
Landau gauge QCD is obtained by neglecting all contributions from irreducible
4-point correlations and by implementing the Slavnov-Taylor identities for the
3-point vertex functions. We solve this coupled set in an one-dimensional
approximation which allows for an analytic infrared expansion necessary to
obtain numerically stable results. This technique, which was also used in our
previous solution of the gluon Dyson-Schwinger equation in the Mandelstam
approximation, is here extended to solve the coupled set of integral equations
for the propagators of gluons and ghosts simultaneously. In particular, the
gluon propagator is shown to vanish for small spacelike momenta whereas the
previoulsy neglected ghost propagator is found to be enhanced in the infrared.
The running coupling of the non-perturbative subtraction scheme approaches an
infrared stable fixed point at a critical value of the coupling, alpha_c
approximately 9.5.Comment: 23 pages, 6 figures, LaTeX2
Problems and Prospects: Public Health Regulation of Dietary Supplements
Dietary supplements are a global business worth more than US$100 billion annually. These supplements are taken by up to 50% of adults and perhaps one-third of children in economically advanced economies. Definitions of dietary supplements differ from country to country, and regulation is generally lax and often seems to be directed more toward promoting commerce than protecting public health. Supplements may directly cause toxic reactions or may interact with other supplements or pharmaceuticals. Some supplements are found to have been contaminated with heavy metals, and others do not contain the expected quantities of active ingredients. In general, supplements are not needed except in cases of established deficiencies, and excess of some nutrients can increase cancer rates. There are important public health reasons for taking some supplements, including folate and iodine in pregnancy. This review discusses the public health concerns associated with dietary supplements and suggests directions for further regulation
Remote magnetic versus manual catheters: evaluation of ablation effect in atrial fibrillation by myocardial marker levels
Background A remote magnetic navigation (MN) system is available for radiofrequency ablation of atrial fibrillation (AF), challenging the conventional manual ablation technique. The myocardial markers were measured to compare the effects of the two types of MN catheters with those of a manual-irrigated catheter in AF ablation. Methods AF patients underwent an ablation procedure using either a conventional manual-irrigated catheter (CIR, n=65) or an MN system utilizing either an irrigated (RMI, n=23) or non-irrigated catheter (RMN, n=26). Levels of troponin T (TnT) and the cardiac isoform of creatin kinase (CKMB) were measured before and after ablation. Results Mean procedure times and total ablation times were longer employing the remote magnetic system. In all groups, there were pronounced increases in markers of myocardial injury after ablation, demonstrating a significant correlation between total ablation time and post-ablation levels of TnT and CKMB (CIR r=0.61 and 0.53, p<0.001; RMI r=0.74 and 0.73, p<0.001; and RMN r=0.51 and 0.59, p<0.01). Time-corrected release of TnT was significantly higher in the CIR group than in the other groups. Of the patients, 59.6% were free from AF at follow-up (12.2± 5.4 months) and there were no differences in success rate between the three groups. Conclusions Remote magnetic catheters may create more discrete and predictable ablation lesions measured by myocardial enzymes and may require longer total ablation time to reach the procedural endpoints. Remote magnetic non-irrigated catheters do not appear to be inferior to magnetic irrigated catheters in terms of myocardial enzyme release and clinical outcome
Prevalence, duration and risk factors for appendicular osteoarthritis in a UK dog population under primary veterinary care.
Osteoarthritis is the most common joint disease diagnosed in veterinary medicine and poses considerable challenges to canine welfare. This study aimed to investigate prevalence, duration and risk factors of appendicular osteoarthritis in dogs under primary veterinary care in the UK. The VetCompassTM programme collects clinical data on dogs attending UK primary-care veterinary practices. The study included all VetCompassTM dogs under veterinary care during 2013. Candidate osteoarthritis cases were identified using multiple search strategies. A random subset was manually evaluated against a case definition. Of 455,557 study dogs, 16,437 candidate osteoarthritis cases were identified; 6104 (37%) were manually checked and 4196 (69% of sample) were confirmed as cases. Additional data on demography, clinical signs, duration and management were extracted for confirmed cases. Estimated annual period prevalence (accounting for subsampling) of appendicular osteoarthritis was 2.5% (CI95: 2.4-2.5%) equating to around 200,000 UK affected dogs annually. Risk factors associated with osteoarthritis diagnosis included breed (e.g. Labrador, Golden Retriever), being insured, being neutered, of higher bodyweight and being older than eight years. Duration calculation trials suggest osteoarthritis affects 11.4% of affected individuals' lifespan, providing further evidence for substantial impact of osteoarthritis on canine welfare at the individual and population level
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