Modifying the temperature dependence of magnetic garnet film coercivity by etching

The temperature dependence of the domain-wall coercive field of epitaxial magnetic garnet films was modified in a defined temperature range by removing the surface layer of the films. Outside the given temperature range the coercivity versus temperature curve did not change. The result supports a model of coercivity according to which different sets of material imperfections are responsible for pinning the domain walls in different temperature regions. Appropriate processing of the samples enables some of the pinning sets to be modified independently of each other

Radiation generated by accelerating and rotating charged black holes in (anti-)de Sitter space

Asymptotic behaviour of gravitational and electromagnetic fields of exact type D solutions from the large Plebanski-Demianski family of black hole spacetimes is analyzed. The amplitude and directional structure of radiation is evaluated in cases when the cosmological constant is non-vanishing, so that the conformal infinities have either de Sitter-like or anti-de Sitter-like character. In particular, explicit relations between the parameters that characterize the sources (that is their mass, electric and magnetic charges, NUT parameter, rotational parameter, and acceleration) and properties of the radiation generated by them are presented. The results further elucidate the physical interpretation of these solutions and may help to understand radiative characteristics of more general spacetimes than those that are asymptotically flat.Comment: 24 pages, 18 figures. To appear in Classical and Quantum Gravit

Gyratons on Melvin spacetime

We present and analyze new exact gyraton solutions of algebraic type II on a background which is static, cylindrically symmetric Melvin universe of type D. For a vanishing electromagnetic field it reduces to previously studied gyratons on Minkowski background. We demonstrate that the solutions are member of a more general family of the Kundt spacetimes. We show that the Einstein equations reduce to a set of mostly linear equations on a transverse 2-space and we discuss the properties of polynomial scalar curvature invariants which are generally non-constant but unaffected by the presence of gyratons.Comment: 15 pages, no figures, journal version extended by appendices B and

Higher-dimensional Kundt waves and gyratons

We present and analyze exact solutions of the Einstein-Maxwell equations in higher dimensions which form a large subclass of the Kundt family of spacetimes. We assume that the cosmological constant may be nonvanishing, and the matter consists of a background aligned electromagnetic field and an additional pure radiation (gyratonic) field with a spin. We show that the field equations reduce to a set of linear equations on the transverse space which can be solved exactly and expressed in terms of the Green functions. We thus find explicit exact gyratonic gravitational and electromagnetic fields created by a radiation beam of null matter with arbitrary profiles of energy density and angular momenta. In the absence of the gyratonic matter we obtain pure nonexpanding higher-dimensional gravitational waves. In particular, we investigate gyratons and waves propagating on backgrounds which are a direct-product of 2-spaces of constant curvature. Such type D or 0 background spacetimes generalize 4-dimensional Nariai, anti-Nariai and Plebanski-Hacyan universes, and conformally flat Bertotti-Robinson and Minkowski spaces. These spacetimes belong to a wider class of spaces which admit the Kahler structure related to the background magnetic field. The obtained wave and gyraton solutions are also members of the recently discussed class of spacetimes with constant scalar invariants (CSI) of the curvature tensor.Comment: 18 pages, no figure

Safety of Statin Pretreatment in Intravenous Thrombolysis for Acute Ischemic Stroke

PubMed ID: 26173726Background and Purpose - A recent meta-analysis investigating the association between statins and early outcomes in acute ischemic stroke (AIS) patients treated with intravenous thrombolysis (IVT) indicated that prestroke statin treatment was associated with increased risk of 90-day mortality and symptomatic intracranial hemorrhage. We investigated the potential association of statin pretreatment with early outcomes in a large, international registry of AIS patients treated with IVT. Methods - We analyzed prospectively collected data from the Safe Implementation of Treatments in Stroke-East registry (SITS-EAST) registry on consecutive AIS patients treated with IVT during an 8-year period. Early clinical recovery within 24 hours was defined as reduction in baseline National Institutes of Health Stroke Scale score of ?10 points. Favorable functional outcome at 3 months was defined as modified Rankin Scale scores of 0 to 1. Symptomatic intracranial hemorrhage was diagnosed using National Institute of Neurological Disorders and Stroke, European-Australasian Acute Stroke Study-II and SITS definitions. Results - A total of 1660 AIS patients treated with IVT fulfilled our inclusion criteria. Patients with statin pretreatment (23%) had higher baseline stroke severity compared with cases who had not received any statin at symptom onset. After adjusting for potential confounders, statin pretreatment was not associated with a higher likelihood of symptomatic intracranial hemorrhage defined by any of the 3 definitions. Statin pretreatment was not related to 3-month all-cause mortality (odds ratio, 0.92; 95% confidence interval, 0.57-1.49; P=0.741) or 3-month favorable functional outcome (odds ratio, 0.81; 95% confidence interval, 0.52-1.27; P=0.364). Statin pretreatment was independently associated with a higher odds of early clinical recovery (odds ratio, 1.91; 95% confidence interval, 1.25-2.92; P=0.003). Conclusions - Statin pretreatment seems not to be associated with adverse outcomes in AIS patients treated with IVT. The effect of statin pretreatment on early functional outcomes in thrombolysed AIS patients deserves further investigation. © 2015 American Heart Association, Inc

Factors influencing in-hospital delay in treatment with intravenous thrombolysis

PubMed ID: 22426311Background and Purpose-: Shortening door-to-needle time (DNT) for the thrombolytic treatment of stroke can improve treatment efficacy by reducing onset-to-treatment time. The goal of our study was to explore the association between DNT and outcome and to identify factors influencing DNT to better understand why some patients are treated late. Methods-: Prospectively collected data from the Safe Implementation of Treatments in Stroke-East registry (SITS-EAST: 9 central and eastern European countries) on all patients treated with thrombolysis between February 2003 and February 2010 were analyzed. Multiple logistic regression analysis was used to identify predictors of DNT ?60 minutes. Results-: Altogether, 5563 patients were treated with thrombolysis within 4.5 hours of symptom onset. Of these, 2097 (38%) had DNT ?60 minutes. In different centers, the proportion of patients treated with DNT ?60 minutes ranged from 18% to 84% (P<0.0001). Patients with longer DNT (in 60-minute increments) had less chance of achieving a modified Rankin Scale score of 0 to 1 at 3 months (adjusted OR, 0.86; 95% CI, 0.77-0.97). DNT ?60 minutes was independently predicted by younger age (in 10-year increments; OR, 0.92; 95% CI, 0.87-0.97), National Institutes of Health Stroke Scale score 7 to 24 (OR, 1.44; 95% CI, 1.2-1.7), onset-to-door time (in 10-minute increments; OR, 1.19; 95% CI, 1.17-1.22), treatment center (P<0.001), and country (P<0.001). Conclusions-: Thrombolysis of patients with older age and mild or severe neurological deficit is delayed. The perception that there is sufficient time before the end of the thrombolytic window also delays treatment. It is necessary to improve adherence to guidelines and to treat patients sooner after arrival to hospital. © 2012 American Heart Association, Inc

Labe IV:Využití 15N a 18O izotopů při studiu napájení a šíření dusičnanové kontaminace na vybraných vodních zdrojích v povodí Labe

Zpráva zpracovává výsledky získané během druhého roku řešení projektu. Sledovány jsou zdroje v povodí Orlice a na pravém břehu Labe mezi Jizerou a Mělníkem. Zdroje byly studovány, jak reagují na srážky a původ dusičnanové kontaminace v závislosti na čase. Pro území jednotlivých zdrojů byly zpracovány hydraulické modely v programu MODFLOW. Proudnice a simulované doby zdržení jsou počítány pomocí programu MODPATH