310 research outputs found
Odd-frequency pairing and Kerr effect in the heavy-fermion superconductor UPt
We study the emergence of odd-frequency superconducting pairing in UPt.
Starting from a tight-binding model accounting for the nonsymmorphic crystal
symmetry of UPt and assuming an order parameter in the
representation, we demonstrate that odd-frequency pairing arises very
generally, as soon as inter-sublattice hopping or spin-orbit coupling is
present. We also show that in the low temperature superconducting phase,
the presence of a chiral order parameter together with spin-orbit coupling,
leads to additional odd-frequency pair amplitudes not present in the or
phases. Furthermore, we show that a finite Kerr rotation in the phase is
only present if odd- pairing also exists.Comment: 8 pages, 2 figure
Odd-frequency superconductivity induced by non-magnetic impurities
A growing body of literature suggests that odd-frequency superconducting pair
amplitudes can be generated in normal metal-superconductor junctions. The
emergence of odd-frequency pairing in these systems is often attributed to the
breaking of translation invariance. In this work, we study the pair symmetry of
a one-dimensional -wave superconductor in the presence of a single
non-magnetic impurity and demonstrate that translation symmetry breaking is not
sufficient for inducing odd-frequency pairing. We consider three kinds of
impurities: a local perturbation of the chemical potential, an impurity
possessing a quantum energy level, and a local perturbation of the
superconducting gap. Surprisingly, we find local perturbations of the chemical
potential do not induce any odd-frequency pairing, despite the fact that they
break translation invariance. Moreover, although odd-frequency can be induced
by both the quantum impurity and the perturbation of the gap, we find these
odd-frequency amplitudes emerge from entirely different kinds of scattering
processes. The quantum impurity generates odd-frequency pairs by allowing one
of the quasiparticles belonging to an equal-time Cooper pair to tunnel onto the
impurity state and then back to the superconductor, giving rise to
odd-frequency amplitudes with a temporal broadening inversely proportional to
the energy level of the impurity. In contrast to this, the perturbation of the
gap leads to odd-frequency pairing by "gluing-together" normal state
quasiparticles from different points in space and time, leading to
odd-frequency amplitudes which are very localized in the time domain.Comment: 7 pages, 1 figur
Efecte d'una mescla estival episòdica en la dinàmica i l'estructura de la comunitat de microorganismes fotosintètics planctònics a l'Estanyol d'en Sisó
Virtual patients design and its effect on clinical reasoning and student experience : a protocol for a randomised factorial multi-centre study
Background
Virtual Patients (VPs) are web-based representations of realistic clinical cases. They are proposed as being an optimal method for teaching clinical reasoning skills. International standards exist which define precisely what constitutes a VP. There are multiple design possibilities for VPs, however there is little formal evidence to support individual design features. The purpose of this trial is to explore the effect of two different potentially important design features on clinical reasoning skills and the student experience. These are the branching case pathways (present or absent) and structured clinical reasoning feedback (present or absent).
Methods/Design
This is a multi-centre randomised 2x2 factorial design study evaluating two independent variables of VP design, branching (present or absent), and structured clinical reasoning feedback (present or absent).The study will be carried out in medical student volunteers in one year group from three university medical schools in the United Kingdom, Warwick, Keele and Birmingham. There are four core musculoskeletal topics. Each case can be designed in four different ways, equating to 16 VPs required for the research. Students will be randomised to four groups, completing the four VP topics in the same order, but with each group exposed to a different VP design sequentially. All students will be exposed to the four designs. Primary outcomes are performance for each case design in a standardized fifteen item clinical reasoning assessment, integrated into each VP, which is identical for each topic. Additionally a 15-item self-reported evaluation is completed for each VP, based on a widely used EViP tool. Student patterns of use of the VPs will be recorded.
In one centre, formative clinical and examination performance will be recorded, along with a self reported pre and post-intervention reasoning score, the DTI. Our power calculations indicate a sample size of 112 is required for both primary outcomes
Factors influencing the implementation, adoption, use, sustainability and scalability of eLearning for family medicine specialty training:A systematic review protocol
Background In 2013, there was a shortage of approximately 7.2 million health workers worldwide, which is larger among family physicians than among specialists. eLearning could provide a potential solution to some of these global workforce challenges. However, there is little evidence on factors facilitating or hindering implementation, adoption, use, scalability and sustainability of eLearning. This review aims to synthesise results from qualitative and mixed methods studies to provide insight on factors influencing implementation of eLearning for family medicine specialty education and training. Additionally, this review aims to identify the actions needed to increase effectiveness of eLearning and identify the strategies required to improve eLearning implementation, adoption, use, sustainability and scalability for family medicine speciality education and training. Methods A systematic search will be conducted across a range of databases for qualitative studies focusing on experiences, barriers, facilitators, and other factors related to the implementation, adoption, use, sustainability and scalability of eLearning for family medicine specialty education and training. Studies will be synthesised by using the framework analysis approach. Discussion This study will contribute to the evaluation of eLearning implementation, adoption, use, sustainability and scalability for family medicine specialty training and education and the development of eLearning guidelines for postgraduate medical education
Hazing: What Ohio High School Teachers, Coaches and Administrators Need to Know
Once thought to be primarily an issue of concern for university fraternities and sororities, hazing has emerged as a disturbing trend with an increase in the number of incidents involving high school student athletes. High school coaches, athletic administrators, and teachers must understand that initiation rites of sport teams can sometimes spiral out of control with grave legal and financial consequences for student athletes and school officials. The purposes of this article are to: Define hazing and review the history of anti-hazing legislation in the United States of America. Describe hazing laws in the State of Ohio. Review current research related to hazing specifically at the high school level. Discuss proactive strategies coaches, administrators, students, teachers, parents, and the community can use to prevent the harmful practices of hazing
General Conditions for Proximity-Induced Odd-Frequency Superconductivity in Two-Dimensional Electronic Systems
We obtain the general conditions for the emergence of odd-frequency superconducting pairing in a two-dimensional (2D) electronic system proximity coupled to a superconductor, making minimal assumptions about both the 2D system and the superconductor. Using our general results we show that a simple heterostructure formed by a monolayer of a group VI transition metal dichalcogenide, such as molybdenum disulfide, and an s-wave superconductor with Rashba spin-orbit coupling exhibits odd-frequency superconducting pairing. Our results allow the identification of a new class of systems among van der Waals heterostructures in which odd-frequency superconductivity should be present
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