751 research outputs found

    Frequency spectra of the sources 3C 295 and 3C 380

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    Interferometric flux density measurements on stellar light source

    Microwave Response and Spin Waves in Superconducting Ferromagnets

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    Excitation of spin waves is considered in a superconducting ferromagnetic slab with the equilibrium magnetization both perpendicular and parallel to the surface. The surface impedance is calculated and its behavior near propagation thresholds is analyzed. Influence of non-zero magnetic induction at the surface is considered in various cases. The results provide a basis for investigation of materials with coexisting superconductivity and magnetism by microwave response measurements.Comment: 10 pages, 7 figure

    Excitation of Spin Waves in Superconducting Ferromagnets

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    This Letter presents a theoretical analysis of propagation of spin waves in a superconducting ferromagnet. The surface impedance was calculated for the case when the magnetization is normal to the sample surface. We found the frequencies at which the impedance and the power absorption have singularities related to the spin wave propagation, and determined the form of these singularities. With a suitable choice of parameters, there is a frequency interval in which two propagating spin waves of the same circular polarization are generated, one of them having a negative group velocity.Comment: 4 pages, 2 figures, submitted to PR

    Comprehensive geriatric assessment in perioperative care: a protocol for a systematic review and qualitative synthesis

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    INTRODUCTION: Comprehensive geriatric assessment (CGA) is an intervention that has been deployed in the perioperative setting with the aim to improve outcomes for older patients admitted to hospital. Older patients undergoing surgery are more likely to have postoperative complications, a longer hospital stay and be discharged to a care facility. Despite the increasing application of this intervention within surgical services, the evidence for CGA remains limited in this group. The aim of this systematic review is to describe CGA as in intervention applied to surgical populations in randomised controlled trials (RCTs) as well as the outcomes assessed. METHODS AND ANALYSIS: A systematic search of RCTs of CGA in surgery will be run in Embase, Medline, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and Cochrane library. Further articles will be identified from reference lists in relevant studies found in the search. A narrative synthesis will be undertaken outlining specialties included, detailed descriptions of the intervention and outcomes. ETHICS AND DISSEMINATION: No ethical approval is required. The results of this review will be published and used as the basis of work to optimise this intervention for future trials in surgical populations. PROSPERO REGISTRATION NUMBER: This review is registered with PROSPERO CRD42020221797

    Vortex shear effects in layered superconductors

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    Motivated by recent transport and magnetization measurements in BSCCO samples [B. Khaykovich et. al., Phys. Rev. B 61, R9261 (2000)], we present a simple macroscopic model describing effects of inhomogeneous current distribution and shear in a layered superconductor. Parameters of the model are deduced from a microscopic calculation. Our model accounts for the strong current non-linearities and the re-entrant temperature dependence observed in the experiment.Comment: 11 pages, 7 figures, submitted to Phys. Rev.

    Magnetoresistive study of antiferromagnetic--weak ferromagnetic transition in single-crystal La2_{2}CuO4+δ_{4+\delta}

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    The resistive measurements were made to study the magnetic field-induced antiferromagnetic (AF) - weak ferromagnetic (WF) transition in La2_2CuO4_4 single-crystal. The magnetic field (DC or pulsed) was applied normally to the CuO2_2 layers. The transition manifested itself in a drastic decrease of the resistance in critical fields of ~5-7 T. The study is the first to display the effect of the AF -WF transition on the conductivity of the La2_2CuO4_4 single-crystal in the parallel - to - CuO2_2 layers direction. The results provide support for the 3-dimensional nature of the hopping conduction of this layered oxide.Comment: 8 pages, 7 figures, RevTe

    Microscopic derivation of Ginzburg-Landau equations for coexistent states of superconductivity and magnetism

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    Ginzburg-Landau (GL) equations for the coexistent states of superconductivity and magnetism are derived microscopically from the extended Hubbard model with on-site repulsive and nearest-neighbor attractive interactions. In the derived GL free energy a cubic term that couples the spin-singlet and spin-triplet components of superconducting order parameters (SCOP) with magnetization exists. This term gives rise to a spin-triplet SCOP near the interface between a spin-singlet superconductor and a ferromagnet, consistent with previous theoretical studies based on the Bogoliubov de Gennes method and the quasiclassical Green's function theory. In coexistent states of singlet superconductivity and antiferromagnetism it leads to the occurrence of pi-triplet SCOPs.Comment: 18 page

    Prevalence and correlates of depressive disorders in people with Type 2 diabetes: results from the International Prevalence and Treatment of Diabetes and Depression (INTERPRET‐DD) study, a collaborative study carried out in 14 countries

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    Aims To assess the prevalence and management of depressive disorders in people with Type 2 diabetes in different countries. Methods People with diabetes aged 18–65 years and treated in outpatient settings were recruited in 14 countries and underwent a psychiatric interview. Participants completed the Patient Health Questionnaire and the Problem Areas in Diabetes scale. Demographic and medical record data were collected. Results A total of 2783 people with Type 2 diabetes (45.3% men, mean duration of diabetes 8.8 years) participated. Overall, 10.6% were diagnosed with current major depressive disorder and 17.0% reported moderate to severe levels of depressive symptomatology (Patient Health Questionnaire scores >9). Multivariable analyses showed that, after controlling for country, current major depressive disorder was significantly associated with gender (women) (PPPPP<0.0001). The proportion of those with either current major depressive disorder or moderate to severe levels of depressive symptomatology who had a diagnosis or any treatment for their depression recorded in their medical records was extremely low and non-existent in many countries (0–29.6%). Conclusions Our international study, the largest of this type ever undertaken, shows that people with diabetes frequently have depressive disorders and also significant levels of depressive symptoms. Our findings indicate that the identification and appropriate care for psychological and psychiatric problems is not the norm and suggest a lack of the comprehensive approach to diabetes management that is needed to improve clinical outcomes
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