338 resultados para Primary Resonances
Resumo:
We present results from complementary characterizations of the primary relaxation rate of a room temperature ionic liquid (RTIL), 1-hexyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl} imide, [C(6)mim][Tf2N], over a wide temperature range. This extensive data set is successfully merged with existing literature data for conductivity, viscosity, and NMR diffusion coefficients thus providing, for the case of RTILs, a unique description of the primary process relaxation map over more than 12 decades in relaxation rate and between 185 and 430 K. This unique data set allows a detailed characterization of the VTF parameters for the primary process, that are: B = 890 K, T-0 = 155.2 K, leading to a fragility index m = 71, corresponding to an intermediate fragility. For the first time neutron spin echo data from a fully deuteriated sample of RTIL at the two main interference peaks, Q = 0.76 and 1.4 angstrom(-1) are presented. At high temperature (T > 250 K), the collective structural relaxation rate follows the viscosity behavior; however at lower temperatures it deviates from the viscosity behavior, indicating the existence of a faster process.
Resumo:
The properties and characteristics of a recently proposed anisotropic metamaterial based upon layered arrays of tightly coupled pairs of "dogbone" shaped stripe conductors have been explored in detail. It has been found that a metamaterial composed of such stacked layers exhibits artificial magnetism and may support backward wave propagation. The equivalent network models of the constitutive conductor pairs arranged in the periodic array have been devised and applied to the identification of the specific types of resonances, and to the analysis of their contribution into the effective dielectric and magnetic properties of the artificial medium. The proposed "dogbone" configuration of conductor pairs has the advantage of being entirely realizable and assemblable in planar technology. It also appears more prospective than simple cut-wire or metal-plate pairs because the additional geometrical parameters provide an efficient control of separation between the electric and magnetic resonances that, in turn, makes it possible to obtain a fairly broadband left-handed behaviour of the structure at low frequencies.
Cardiac rehabilitation uptake following myocardial infarction: cross-sectional study in primary care
Resumo:
Background Policies suggest that primary care should be more involved in delivering cardiac rehabilitation. However, there is a lack of information about what is known in primary care regarding patients' invitation or attendance. Aim To determine, within primary care, how many patients are invited to and attend rehabilitation after myocardial infarction (MI), examine sociodemographic factors related to invitation, and compare quality of life between those who do and do not attend. Design of study Review of primary care paper and computer records; cross-sectional questionnaire. Setting Northern Ireland general practices (38); stratified sample, based on practice size and health board area. Method Patients, identified from primary care records, 12-16?weeks after a confirmed diagnosis of MI, were posted questionnaires, including a validated MacNew post-MI quality-of-life questionnaire. Practices returned anonymised data for non-responders. Results Information about rehabilitation was available for 332 of the 432 patients identified (76.9%): 162 (37.5%) returned questionnaires. Of the total sample, 54.4% (235/432) were invited and 37.0% (160/432) attended; of those invited, 68.1% (160/235) attended. Invited patients were younger than those not invited (mean age 63?years [standard deviation SD 16] versus 68.5?years [SD 16]); mean difference 5.5?years (95% confidence interval [CI] = 1.7 to 9.3). Among questionnaire responders, those who attended were younger and reported better emotional, physical, and social functioning than non-attenders (P = 0.01; mean differences 0.44 (95% CI = 0.11 to 0.77), 0.48 (95% CI = 0.10 to 0.85) and 0.54 (95% CI = 0.15 to 0.94) respectively). Conclusion Innovative strategies are needed to improve cardiac rehabilitation uptake, integration of hospital and primary care services, and healthcare professionals' awareness of patients' potential for health gain after MI.