535 research outputs found

    Wedge Local Deformations of Charged Fields leading to Anyonic Commutation Relations

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    The method of deforming free fields by using multiplication operators on Fock space, introduced by G. Lechner in [11], is generalized to a charged free field on two- and three-dimensional Minkowski space. In this case the deformation function can be chosen in such a way that the deformed fields satisfy generalized commutation relations, i.e. they behave like Anyons instead of Bosons. The fields are "polarization free" in the sense that they create only one-particle states from the vacuum and they are localized in wedges (or "paths of wedges"), which makes it possible to circumvent a No-Go theorem by J. Mund [12], stating that there are no free Anyons localized in spacelike cones. The two-particle scattering matrix, however, can be defined and is different from unity

    Massless, String Localized Quantum Fields for Any Helicity

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    For any massless, irreducible representation of the covering of the proper, orthochronous Poincar\'e group we construct covariant, free quantum fields that generate the representation space from the vacuum and are localized in semi-infinite strings in the sense of commutation or anti-commutation of the field operators at space-like separation of the strings.Comment: Minor corrections. To be published in Journal of Mathematical Physic

    Increased prevalence of sleep disturbances and daytime sleepiness in subjects with bronchial asthma: a population study of young adults in three European countries

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldThe aim of this study was to investigate whether asthma is associated with decreased quality of sleep and increased daytime sleepiness. The study involved a random population of 2,202 subjects supplemented by 459 subjects with suspected asthma, aged 20-45 yrs. The subjects were from Reykjavik (Iceland), Uppsala and Göteborg (Sweden) and Antwerp (Belgium), and participated in the European Community Respiratory Health Survey. The investigation included a structured interview, methacholine challenge, skinprick tests and a questionnaire on sleep disturbances. Participants in Iceland and Sweden also estimated their sleep times and made peak expiratory flow (PEF) recordings during a period of 1 week. Asthma was defined as self-reported physician-diagnosed asthma with current asthma-related symptoms (n = 267). Difficulties inducing sleep (DIS) and early morning awakenings (EMA) were about twice as common, and daytime sleepiness 50% more common, in asthmatics compared with subjects without asthma. After adjusting for possible confounders, a positive association was found between asthma and: DIS (odds ratio (OR) = 1.8); EMA (OR = 2.0); daytime sleepiness (OR = 1.6); snoring (OR = 1.7); and self reported apnoeas (OR = 3.7). Allergic rhinitis, which was reported by 71% of subjects with asthma, was independently related to DIS (OR = 2.0) and daytime sleepiness (OR = 1.3). A significant correlation was found between the number of asthma-related symptoms and sleep disturbances (p < 0.001). Asthma is associated with decreased subjective quality of sleep and increased daytime sleepiness. Concurrent allergic rhinitis may be an important underlying cause of sleep impairment in asthmatic patients

    A blinded comparison of fluticasone propionate with budesonide via powder devices in adult patients with moderate-to-severe asthma: a clinical evaluation

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    In Vitro and in vivo data have demonstrated that there are detectable differences between inhaled corticosteroids commonly used to treat asthma. However, controversy still remains as to whether these differences translate into clinical benefits. This 12-week, international, randomized, doubleblind, parallel-group study was undertaken to compare the efficacy and safety of fluticasone propionate (FP) 800 μg daily, administered as a powder via the Diskhaler®, and budesonide (BUD) 1600 μg daily, administered using the Turbuhaler®, in adult patients with moderate-tosevere asthma. A total of 518 patients participated in the study, 256 of whom received FP and 262 BUD. Assessment of mean morning peak expiratory flow (PEF) over the 12-week treatment period revealed a statistically significant difference in efficacy between FP 800 μg daily and BUD 1600 μg daily in favour of FP (p = 0.003), with an overall improvement of 20.9 l/min with FP compared with 12.4 l/min on BUD. Statistically significant differences in favour of FP were seen over the 12 weeks for mean evening PEF (p = 0.04), diurnal PEF variation (p = 0.03) and percentage predicted PEF (p = 0.003), as well as forced expiratory volume (p = 0.008), forced vital capacity (p = 0.02) and PEF (p = 0.005) measured at clinic visits. The median percentage of symptom-free nights increased over the 12-week study period in both treatment groups, with similar changes seen for the median percentage of days with symptom score < 2, rescue medication use and exacerbations of asthma. The incidence of adverse events was found to be comparable in the two treatment groups. The geometric mean ratios of serum cortisol levels were found to be 1.03 for FP, indicating no mean hypothalamic-pituitary-adrenal axis suppression from baseline, and 0.93 for BUD (p = 0.0002 compared with FP). In summary, FP 800 μg daily showed a greater efficacy/safety ratio in the treatment of moderate-to-severe asthma than BUD 1600 μg daily

    Near-Earth plasma sheet boundary dynamics during substorm dipolarization.

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    We report on the large-scale evolution of dipolarization in the near-Earth plasma sheet during an intense (AL ~ -1000 nT) substorm on August 10, 2016, when multiple spacecraft at radial distances between 4 and 15 R E were present in the night-side magnetosphere. This global dipolarization consisted of multiple short-timescale (a couple of minutes) B z disturbances detected by spacecraft distributed over 9 MLT, consistent with the large-scale substorm current wedge observed by ground-based magnetometers. The four spacecraft of the Magnetospheric Multiscale were located in the southern hemisphere plasma sheet and observed fast flow disturbances associated with this dipolarization. The high-time-resolution measurements from MMS enable us to detect the rapid motion of the field structures and flow disturbances separately. A distinct pattern of the flow and field disturbance near the plasma boundaries was found. We suggest that a vortex motion created around the localized flows resulted in another field-aligned current system at the off-equatorial side of the BBF-associated R1/R2 systems, as was predicted by the MHD simulation of a localized reconnection jet. The observations by GOES and Geotail, which were located in the opposite hemisphere and local time, support this view. We demonstrate that the processes of both Earthward flow braking and of accumulated magnetic flux evolving tailward also control the dynamics in the boundary region of the near-Earth plasma sheet.Graphical AbstractMultispacecraft observations of dipolarization (left panel). Magnetic field component normal to the current sheet (BZ) observed in the night side magnetosphere are plotted from post-midnight to premidnight region: a GOES 13, b Van Allen Probe-A, c GOES 14, d GOES 15, e MMS3, g Geotail, h Cluster 1, together with f a combined product of energy spectra of electrons from MMS1 and MMS3 and i auroral electrojet indices. Spacecraft location in the GSM X-Y plane (upper right panel). Colorcoded By disturbances around the reconnection jets from the MHD simulation of the reconnection by Birn and Hesse (1996) (lower right panel). MMS and GOES 14-15 observed disturbances similar to those at the location indicated by arrows

    First Results from ARTEMIS, a New Two-Spacecraft Lunar Mission: Counter-Streaming Plasma Populations in the Lunar Wake

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    We present observations from the first passage through the lunar plasma wake by one of two spacecraft comprising ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun), a new lunar mission that re-tasks two of five probes from the THEMIS magnetospheric mission. On Feb 13, 2010, ARTEMIS probe P1 passed through the wake at 3.5 lunar radii downstream from the Moon, in a region between those explored by Wind and the Lunar Prospector, Kaguya, Chandrayaan, and Chang'E missions. ARTEMIS observed interpenetrating proton, alpha particle, and electron populations refilling the wake along magnetic field lines from both flanks. The characteristics of these distributions match expectations from self-similar models of plasma expansion into vacuum, with an asymmetric character likely driven by a combination of a tilted interplanetary magnetic field and an anisotropic incident solar wind electron population. On this flyby, ARTEMIS provided unprecedented measurements of the interpenetrating beams of both electrons and ions naturally produced by the filtration and acceleration effects of electric fields set up during the refilling process. ARTEMIS also measured electrostatic oscillations closely correlated with counter-streaming electron beams in the wake, as previously hypothesized but never before directly measured. These observations demonstrate the capability of the comprehensively instrumented ARTEMIS spacecraft and the potential for new lunar science from this unique two spacecraft constellation

    Observations of whistler mode waves with nonlinear parallel electric fields near the dayside magnetic reconnection separatrix by the Magnetospheric Multiscale mission

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    We show observations from the Magnetospheric Multiscale (MMS) mission of whistler mode waves in the Earth's low-latitude boundary layer (LLBL) during a magnetic reconnection event. The waves propagated obliquely to the magnetic field toward the X line and were confined to the edge of a southward jet in the LLBL. Bipolar parallel electric fields interpreted as electrostatic solitary waves (ESW) are observed intermittently and appear to be in phase with the parallel component of the whistler oscillations. The polarity of the ESWs suggests that if they propagate with the waves, they are electron enhancements as opposed to electron holes. The reduced electron distribution shows a shoulder in the distribution for parallel velocities between 17,000 and 22,000 km/s, which persisted during the interval when ESWs were observed, and is near the phase velocity of the whistlers. This shoulder can drive Langmuir waves, which were observed in the high-frequency parallel electric field data
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