1,109 research outputs found

    Мотив граалю як ідеологічний чинник у фентезійній Артуріані ХХ століття

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    У статті досліджено еволюцію традиційного мотиву Граалю в аспекті авторської інтерпретації, на матеріалі циклів фентезійних романів С.Лохеда, М.Ц.Бредлі та Г.Дж.Кея розглянуто особливості імплантації зазначеного мотиву у фантастичний текст та реалізацію його субмотивів і функцій у залежності від авторської ідеології.В статье исследуется эволюция традиционного мотива Грааля в аспекте авторской интерпретации, на материале циклов фэнтезийных романов С.Лохеда, М.Ц.Бредли та Г.Дж.Кея рассмотрены особенности имплантации указанного мотива в фантастический текст и реализацию его субмотивов и функций в зависимости от авторской идеологии.The article offers the analisys of traditional Grail motif in aspect of the author's interpretation; on a base of fantasy cycles by S.Lawhead, M.Z.Bradley and G.G.Key. There are examined specifics of such motif’s implantation into fantastic texts and instantiation of it’s submotifs and functions according to the author’s ideology

    Anisotropic Colossal Magnetoresistance Effects in Fe_{1-x}Cu_xCr_2S_4

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    A detailed study of the electronic transport and magnetic properties of Fe1x_{1-x}Cux_xCr2_2S4_4 (x0.5x \leq 0.5) on single crystals is presented. The resistivity is investigated for 2T3002 \leq T \leq 300 K in magnetic fields up to 14 Tesla and under hydrostatic pressure up to 16 kbar. In addition magnetization and ferromagnetic resonance (FMR) measurements were performed. FMR and magnetization data reveal a pronounced magnetic anisotropy, which develops below the Curie temperature, TCT_{\mathrm{C}}, and increases strongly towards lower temperatures. Increasing the Cu concentration reduces this effect. At temperatures below 35 K the magnetoresistance, MR=ρ(0)ρ(H)ρ(0)MR = \frac{\rho(0) - \rho(H)}{\rho(0)}, exhibits a strong dependence on the direction of the magnetic field, probably due to an enhanced anisotropy. Applying the field along the hard axis leads to a change of sign and a strong increase of the absolute value of the magnetoresistance. On the other hand the magnetoresistance remains positive down to lower temperatures, exhibiting a smeared out maximum with the magnetic field applied along the easy axis. The results are discussed in the ionic picture using a triple-exchange model for electron hopping as well as a half-metal utilizing a band picture.Comment: some typos correcte

    Tempo and mode of performance evolution across multiple independent origins of adhesive toe pads in lizards

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    Understanding macroevolutionary dynamics of trait evolution is an important endeavor in evolutionary biology. Ecological opportunity can liberate a trait as it diversifies through trait space, while genetic and selective constraints can limit diversification. While many studies have examined the dynamics of morphological traits, diverse morphological traits may yield the same or similar performance and as performance is often more proximately the target of selection, examining only morphology may give an incomplete understanding of evolutionary dynamics. Here, we ask whether convergent evolution of pad‐bearing lizards has followed similar evolutionary dynamics, or whether independent origins are accompanied by unique constraints and selective pressures over macroevolutionary time. We hypothesized that geckos and anoles each have unique evolutionary tempos and modes. Using performance data from 59 species, we modified Brownian motion (BM) and Ornstein–Uhlenbeck (OU) models to account for repeated origins estimated using Bayesian ancestral state reconstructions. We discovered that adhesive performance in geckos evolved in a fashion consistent with Brownian motion with a trend, whereas anoles evolved in bounded performance space consistent with more constrained evolution (an Ornstein–Uhlenbeck model). Our results suggest that convergent phenotypes can have quite distinctive evolutionary patterns, likely as a result of idiosyncratic constraints or ecological opportunities

    Optical polarization grating in semiconductors induced by exciton-polaritons

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    A scattering-state approach is proposed to study the propagation of extremely short optical pulses through semiconductor heterostructures. The formalism is applied to the propagation of exciton polaritons: Our simulated experiments predict the formation of an exciton-induced polarization grating when the light pulse is resonant with the excitonic transition, and suggest proper physical conditions for its experimental detection. Moreover, our analysis of the polariton transport in thick semiconductor layers reveals a decrease of the average polariton group velocity as a function of time, which we ascribe to a re-emission—reabsorption of light by excitons

    A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field

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    Objective The aim of this study was to compare the use of high-resolution phase and QSM images acquired at ultra-high field in the investigation of multiple sclerosis (MS) lesions with peripheral rings, and to discuss their usefulness for drawing inferences about underlying tissue composition. Materials and methods Thirty-nine Subjects were scanned at 7 T, using 3D T2*-weighted and T1-weighted sequences. Phase images were then unwrapped and filtered, and quantitative susceptibility maps were generated using a thresholded k-space division method. Lesions were compared visually and using a 1D profiling algorithm. Results Lesions displaying peripheral rings in the phase images were identified in 10 of the 39 subjects. Dipolar projections were apparent in the phase images outside of the extent of several of these lesions; however, QSM images showed peripheral rings without such projections. These projections appeared ring-like in a small number of phase images where no ring was observed in QSM. 1D profiles of six well-isolated example lesions showed that QSM contrast corresponds more closely to the magnitude images than phase contrast. Conclusions Phase images contain dipolar projections, which confounds their use in the investigation of tissue composition in MS lesions. Quantitative susceptibility maps correct these projections, providing insight into the composition of MS lesions showing peripheral rings

    Smoking and health-related quality of life in English general population: Implications for economic evaluations

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    Copyright @ 2012 Vogl et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.Background: Little is known as to how health-related quality of life (HRQoL) when measured by generic instruments such as EQ-5D differ across smokers, ex-smokers and never-smokers in the general population; whether the overall pattern of this difference remain consistent in each domain of HRQoL; and what implications this variation, if any, would have for economic evaluations of tobacco control interventions. Methods: Using the 2006 round of Health Survey for England data (n = 13,241), this paper aims to examine the impact of smoking status on health-related quality of life in English population. Depending upon the nature of the EQ-5D data (i.e. tariff or domains), linear or logistic regression models were fitted to control for biology, clinical conditions, socio-economic background and lifestyle factors that an individual may have regardless of their smoking status. Age- and gender-specific predicted values according to smoking status are offered as the potential 'utility' values to be used in future economic evaluation models. Results: The observed difference of 0.1100 in EQ-5D scores between never-smokers (0.8839) and heavy-smokers (0.7739) reduced to 0.0516 after adjusting for biological, clinical, lifestyle and socioeconomic conditions. Heavy-smokers, when compared with never-smokers, were significantly more likely to report some/severe problems in all five domains - mobility (67%), self-care (70%), usual activity (42%), pain/discomfort (46%) and anxiety/depression (86%) -. 'Utility' values by age and gender for each category of smoking are provided to be used in the future economic evaluations. Conclusion: Smoking is significantly and negatively associated with health-related quality of life in English general population and the magnitude of this association is determined by the number of cigarettes smoked. The varying degree of this association, captured through instruments such as EQ-5D, may need to be fed into the design of future economic evaluations where the intervention being evaluated affects (e.g. tobacco control) or is affected (e.g. treatment for lung cancer) by individual's (or patients') smoking status

    Shortâ TR, Coherent, Gradient Echo Imaging

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    When a spin system is repeatedly disturbed by a fast repetition of RF pulses, the transverse magnetization after each new RF pulse approaches a steadyâ state value which is smaller than the thermal equilibrium value. The spin system takes a finite number of pulses before this steadyâ state is reached in a time that depends on both the T1 of the tissue and the flip angle of the RF pulse. The focus of this unit is on understanding the buildâ up of the magnetization to steadyâ state and the practical implementation of the simplest forms of imaging in the steadyâ state. Sequences utilizing a steadyâ state approach can be broadly classified as steadyâ state coherent (SSC) and steadyâ state incoherent (SSI) sequences. The SSC behavior is the subject of this unit.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145400/1/cpmib0502.pd

    Standardisation of labial salivary gland histopathology in clinical trials in primary Sjögren's syndrome

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    Labial salivary gland (LSG) biopsy is used in the classification of primary Sjögren's syndrome (PSS) and in patient stratification in clinical trials. It may also function as a biomarker. The acquisition of tissue and histological interpretation is variable and needs to be standardised for use in clinical trials. A modified European League Against Rheumatism consensus guideline development strategy was used. The steering committee of the ad hoc working group identified key outstanding points of variability in LSG acquisition and analysis. A 2-day workshop was held to develop consensus where possible and identify points where further discussion/data was needed. These points were reviewed by a subgroup of experts on PSS histopathology and then circulated via an online survey to 50 stakeholder experts consisting of rheumatologists, histopathologists and oral medicine specialists, to assess level of agreement (0–10 scale) and comments. Criteria for agreement were a mean score ≥6/10 and 75% of respondents scoring ≥6/10. Thirty-nine (78%) experts responded and 16 points met criteria for agreement. These points are focused on tissue requirements, identification of the characteristic focal lymphocytic sialadenitis, calculation of the focus score, identification of germinal centres, assessment of the area of leucocyte infiltration, reporting standards and use of prestudy samples for clinical trials. We provide standardised consensus guidance for the use of labial salivary gland histopathology in the classification of PSS and in clinical trials and identify areas where further research is required to achieve evidence-based consensus
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