6,613 research outputs found
Scaling Relations in the Vortex State of Nodal Superconductors
In contrast to multigap superconductors (e.g. MgB), the low-temperature
properties of nodal superconductors are dominated by nodal excitations. Here we
extend for a variety of nodal superocnductors the earlier work by Simon and Lee
and K\"ubert and Hirschfeld. The scaling relations seen in the thermodynamics
and the thermal conductivity will provide an unequivocal test of nodal
superconductivity.Comment: 9 pages, 3 figure
Out of plane optical conductivity in d-wave superconductors
We study theoretically the out of plane optical conductivity of d-wave
superconductors in the presence of impurities at T=0K. Unlike the usual
approach, we assume that the interlayer quasi-particle transport is due to
coherent tunneling. The present model describes the T^2 dependence of the out
of plane superfluid density observed in YBCO and Tl2201 for example. In the
optical conductivity there is no Drude peak in agreement with experiment, and
the interlayer Josephson tunneling is also assured in this model. In the
unitary limit we predict a step like behaviour around omega=Delta in both the
real and imaginary part of the optical conductivity.Comment: 7 pages, 7 figure
Urban School-Based Behavioral Health Providers\u27 Attitudes Towards Evidence Based Practices
Evidence Based Practices (EBPs) in schools show promise in meeting the behavioral health needs of urban students, however there are multiple barriers to implementation. Providers’ attitudes towards EBPs may be one of these barriers. Through a cross sectional survey design, this dissertation answers four major research questions: 1) Is the EBPAS-50 an appropriate tool to use with school based behavioral health providers, 2) Do attitudes vary depending on level of experience (student vs. professional), 3) Do attitudes vary depending on a practitioners’ hire status (school-hired vs. non-school hired), and 4) Do EBPAS-50 scores predict implementation of EBPs? Participants were 160 school behavioral health providers who provided at least one hour per week of direct or indirect services within the Boston Public Schools. Results indicated that the factor structures for the EBPAS-50 and EBPAS- 15 did not hold with this population, however the EBPAS-15 was used for further analysis as it has been validated many times since its introduction. Using the EBPAS-15: 1) graduate students reported more positive attitudes than professionals, 2) school-hired providers reported more positive attitudes than non-school hired providers, and 3) there was no correlation between attitudes and use of EBPs. Though differences may have been statistically significant, it is questionable as to whether these differences are practically significant as the average, rounded, response from providers indicated that they agreed with EBPs to “a great extent”. This suggests need for ongoing research to identify: 1) aspects of evidence based practices that are important to school-based providers, and 2) a revised tool to measure the attitudes of school-based providers towards EBPs
Half quantum vortex in superfluid He-A phase in parallel plate geometry
The half quantum vortex(HQV) in condensate has been studied, since it was
predicted by Salomaa and Volovik in superfluid He-A phase. However, an
experimental evidence for its existence has not been reported so far. Motivated
by a recent experimental report by Yamashita et al\cite{yamashita}, we study
the HQVs in superfluid He confined between two parallel plates with a gap D
10 m in the presence of a magnetic field H 26 mT
perpendicular to the parallel plates. We find that the bound HQVs are more
stable than the singular vortices and free pairs of HQVs, when the rotation
perpendicular to the parallel plates is below the critical speed, 2 rad/s. The bound pair of HQVs accompanies the tilting of -vector out of the plane, which leads to an additional absorption in NMR
spectra. Our study appears to describe the temperature and rotation dependence
of the observed satellite NMR signal, which supports the existence of the HQVs
in He.Comment: 5 pages, 5 figure
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