613 research outputs found
On the existence of dyons and dyonic black holes in Einstein-Yang-Mills theory
We study dyonic soliton and black hole solutions of the
Einstein-Yang-Mills equations in asymptotically anti-de Sitter space. We prove
the existence of non-trivial dyonic soliton and black hole solutions in a
neighbourhood of the trivial solution. For these solutions the magnetic gauge
field function has no zeros and we conjecture that at least some of these
non-trivial solutions will be stable. The global existence proof uses local
existence results and a non-linear perturbation argument based on the (Banach
space) implicit function theorem.Comment: 23 pages, 2 figures. Minor revisions; references adde
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Development and calibration of an on-line aerosol monitor for PHEBUS test FPT1
An on-line aerosol monitor (OLAM2) has been developed and tested for PHEBUS test FPT1. OLAM2 utilizes new detachable fiber optic cables and sapphire light pipes for light transmission between the OLAM and the electronics. This light transmission system was tested and found to provide better signal-to-noise performance than was achieved with the continuous fibers used for test FPT0. An additional advantage of the detachable fiber/light pipe system is ease of installation. Aerosol testing (OLAM calibration) was performed in order to verify adequate signal-to-noise performance of the new fiber optic system over the specified operating conditions and to check the quantitative light attenuation measurements against theoretical predictions. Results of the testing indicated that light extinction measurements obtained during Phebus tests could be used to estimate aerosol volume concentrations, if diamond window fouling can be avoided. OLAM2 was also subjected to a proof pressure test and a long-term thermal stability test. These tests verified the mechanical and thermal integrity of the OLAM within design specifications. Long-term output signal stability was also verified with the system maintained at design temperature and half-design pressure
The acquisition of Sign Language: The impact of phonetic complexity on phonology
Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality
The search of higher multipole radiation in gravitational waves from compact binary coalescences by a minimally-modelled pipeline
The coherent WaveBurst (cWB) pipeline implements a minimally-modelled search to find a coherent response in the network of gravitational wave detectors of the LIGO-Virgo Col-laboration in the time-frequency domain. In this manuscript, we provide a timely introduction to an extension of the cWB analysis to detect spectral features beyond the main quadrupolar emission of gravitational waves during the inspiral phase of compact binary coalescences; more detailed discussion will be provided in a forthcoming paper [1]. The search is performed by defining specific regions in the time-frequency map to extract the energy of harmonics of main quadrupole mode in the inspiral phase. This method has already been used in the GW190814 discovery paper (Astrophys. J. Lett. 896 L44). Here we show the procedure to detect the (3, 3) multipole in GW190814 within the cWB framework
Anatomy of ethylene-induced floral-organ abscission in Chamelaucium uncinatum (Myrtaceae)
Postharvest abscission of Geraldton waxflower (Chamelaucium uncinatum Schauer) flower buds and flowers is ethylene-mediated. Exposure of floral organs to exogenous ethylene (1 mu L L-1) for 6 h at 20 degrees C induced separation at a morphologically and anatomically distinct abscission zone between the pedicel and. oral tube. Flower buds with opening petals and flowers with a nectiferous hypanthium were generally more responsive to exogenous ethylene than were flower buds enclosed in shiny bracteoles and aged (senescing) flowers. The anatomy of abscission-zone cells did not change at sequential stages of floral development from immature buds to aged flowers. The zone comprised a layer of small, laterally elongated-to-rounded, closely packed and highly protoplasmic parenchyma cells. Abscission occurred at a two- to four-cell-wide separation layer within the abscission zone. The process involved degradation of the middle lamella between separation layer cells. Following abscission, cells on both the proximal and distal faces of the separation layer became spherical, loosely packed and contained degenerating protoplasm. Central vascular tissues within the surrounding band of separation layer cells became torn and fractured. For flower buds, bracteoles that enclose the immature floral tube also separated at an abscission zone. However, this secondary abscission zone appeared less sensitive to ethylene than the primary ( central). oral-tube abscission zone as bracteoles generally only completely abscised when exposed to 10 mu L L-1 ethylene for the longer period of 24 h at 20 degrees C. The smooth surfaces of abscised separation-layer cells suggest that hydrolase enzymes degrade the middle lamella between adjacent cell walls
The long helical jet of the Lighthouse nebula, IGR J11014-6103
Jets from rotation-powered pulsars have so far only been observed in systems
moving subsonically trough their ambient medium and/or embedded in their
progenitor supernova remnant (SNR). Supersonic runaway pulsars are also
expected to produce jets, but they have not been confirmed so far. We
investigated the nature of the jet-like structure associated to the INTEGRAL
source IGR J11014-6103 (the "Lighthouse nebula"). The source is a neutron star
escaping its parent SNR MSH 11-61A supersonically at a velocity exceeding 1000
km/s. We observed the Lighthouse nebula and its jet-like X-ray structure
through dedicated high spatial resolution observations in X-rays (Chandra) and
radio band (ATCA). Our results show that the feature is a true pulsar's jet. It
extends highly collimated over >11pc, displays a clear precession-like
modulation, and propagates nearly perpendicular to the system direction of
motion, implying that the neutron star's spin axis in IGR J11014-6103 is almost
perpendicular to the direction of the kick received during the supernova
explosion. Our findings suggest that jets are common to rotation-powered
pulsars, and demonstrate that supernovae can impart high kick velocities to
misaligned spinning neutron stars, possibly through distinct, exotic,
core-collapse mechanisms.Comment: 8 pages, 6 figures, 1 table. Discussion (sec.3) expanded and typos
fixed; results unchanged. Published on A&
Guideline for the management of acute asthma in adults: 2013 update
Acute asthma attacks (asthma exacerbations) are increasing episodes of shortness of breath, cough, wheezing or chest tightness associated with a decrease in airflow that can be quantified and monitored by measurement of lung function (peak expiratory flow (PEF) or forced expiratory volume in the 1st second) and requiring emergency room treatment or admission to hospital for acute asthma and/or systemic glucocorticosteroids for management. The goals of treatment are to relieve hypoxaemia and airflow obstruction as quickly as possible, restore lung function, and provide a suitable plan to avoid relapse. Severe exacerbations are potentially life-threatening and their treatment requires baseline assessment of severity, close monitoring, and frequent reassessment using objective measures of lung function (PEF) and oxygen saturation. Patients at high risk of asthma-related death require particular attention. First-line therapy consists of oxygen supplementation, repeated administration of inhaled short-acting bronchodilators (beta-2-agonists and ipratropium bromide), and early systemic glucocorticosteroids. Intravenous magnesium sulphate and aminophylline are second- and third-line treatment strategies, respectively, for poorly responding patients. Intensive care is indicated for severe asthma that is not responsive to first-line treatment. Antibiotics are only indicated when there are definite features of bacterial infection. Factors that precipitated the acute asthma episode should be identified and preventive measures implemented. Acute asthma is preventable with optimal control of chronic asthma
Some Like It Fat: Comparative Ultrastructure of the Embryo in Two Demosponges of the Genus Mycale (Order Poecilosclerida) from Antarctica and the Caribbean
0000-0002-7993-1523© 2015 Riesgo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License [4.0], which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article
Benzodiazepine Use and Misuse Among Patients in a Methadone Program
<p>Abstract</p> <p>Background</p> <p>Benzodiazepines (BZD) misuse is a serious public health problem, especially among opiate-dependent patients with anxiety enrolled in methadone program because it puts patients at higher risk of life-threatening multiple drug overdoses. Both elevated anxiety and BZD misuse increase the risk for ex-addicts to relapse. However, there is no recent study to assess how serious the problem is and what factors are associated with BZD misuse. This study estimates the prevalence of BZD misuse in a methadone program, and provides information on the characteristics of BZD users compared to non-users.</p> <p>Methods</p> <p>An anonymous survey was carried out at a methadone program in Baltimore, MD, and all patients were invited to participate through group meetings and fliers around the clinic on a voluntary basis. Of the 205 returned questionnaires, 194 were complete and entered into final data analysis. Those who completed the questionnaire were offered a $5 gift card as an appreciation.</p> <p>Results</p> <p>47% of the respondents had a history of BZD use, and 39.8% used BZD without a prescription. Half of the BZD users (54%) started using BZD after entering the methadone program, and 61% of previous BZD users reported increased or resumed use after entering methadone program. Compared to the non-users, BZD users were more likely to be White, have prescribed medication for mental problems, have preexistent anxiety problems before opiate use, and had anxiety problems before entering methadone program. They reported more mental health problems in the past month, and had higher scores in anxiety state, depression and perceived stress (p < .05).</p> <p>Conclusions</p> <p>Important information on epidemiology of BZD misuse among methadone-maintenance patients suggests that most methadone programs do not address co-occurring anxiety problems, and methadone treatment may trigger onset or worsening of BZD misuse. Further study is needed to explore how to curb misuse and abuse of BZD in the addiction population, and provide effective treatments targeting simultaneously addiction symptoms, anxiety disorders and BZD misuse.</p
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