58 research outputs found
Advance care planning for patients with end-stage kidney disease on dialysis: narrative review of the current evidence, and future considerations
Patients with end-stage kidney disease (ESKD) have a high symptom-burden and high rates of morbidity and mortality. Despite this, evidence has shown that this patient group does not have timely discussions to plan for deterioration and death, and at the end of life there are unmet palliative care needs. Advance care planning is a process that can help patients share their personal values and preferences for their future care and prepare for declining health. Earlier, more integrated and holistic advance care planning has the potential to improve access to care services, communication, and preparedness for future decision-making and changing circumstances. However, there are many barriers to successful implementation of advance care planning in this population. In this narrative review we discuss the current evidence for advance care planning in patients on dialysis, the data around the barriers to advance care planning implementation, and interventions that have been trialled. The review explores whether the concepts and approaches to advance care planning in this population need to be updated to encompass current and future care. It suggests that a shift from a problem-orientated approach to a goal-orientated approach may lead to better engagement, with more patient-centred and satisfying outcomes
Effects of Magnetic Order on the Upper Critical Field of UPt
I present a Ginzburg-Landau theory for hexagonal oscillations of the upper
critical field of UPt near . The model is based on a
representation for the superconducting order parameter,
, coupled to an in-plane AFM order parameter,
. Hexagonal anisotropy of arises from the weak in-plane
anisotropy energy of the AFM state and the coupling of the superconducting
order parameter to the staggered field. The model explains the important
features of the observed hexagonal anisotropy [N. Keller, {\it et al.}, Phys.
Rev. Lett. {\bf 73}, 2364 (1994).] including: (i) the small magnitude, (ii)
persistence of the oscillations for , and (iii) the change in
sign of the oscillations for and (the temperature at the
tetracritical point). I also show that there is a low-field crossover
(observable only very near ) below which the oscillations should vanish.Comment: 9 pages in a RevTex (3.0) file plus 2 postscript figures (uuencoded).
Submitted to Physical Review B (December 20, 1994)
Surface superconductivity and order parameter suppression in UPt
We show that a recent measurement of surface superconductivity in UPt
(Keller {\it et. al.}, Phys. Rev. Lett. {\bf 73}, 2364 (1994)) can be
understood if the superconducting pair wavefunction is suppressed
anisotropically at a vacuum to superconductor interface. Further measurements
of surface superconductivity can distinguish between the various
phenomenological models of superconducting UPt.Comment: 4 pages, latex, 2 Figures available upon request
([email protected]
Phase diagram of UPt in the model
The phase diagram of the unconventional superconductor UPt is explained
under the long-standing hypothesis that the pair wavefunction belongs to the
representation of the point group. The main objection to this theory
has been that it disagrees with the experimental phase diagram when a field is
applied along the c-axis. By a careful analysis of the free energy this
objection is shown to be incorrect. This singlet theory also explains the
unusual anisotropy in the upper critical field curves, often thought to
indicate a triplet pair function.Comment: 11 pages, Revtex, 2 figures (uuencoded, gzip'ed Postscript
Magnetoelectric effects in ferromagnetic cobalt/ferroelectric copolymer multilayer films
Boron carbide based solid state neutron detectors: the effects of bias and time constant on detection efficiency
Surface superconductivity and in UPt
Surface superconductivity is studied within Ginzburg-Landau theory for two
classes of models for the order parameter of UPt. The first class assumes
two independent one-dimensional order parameters ( models), while the
second assumes a single two-dimensional order parameter ( models).
is calculated for all cases where the surface normal and magnetic field lie
along high symmetry directions. Assuming specular reflection, it is found that
except when , the ratio is either
unity or equals its `s-wave' value 1.695, although the precise vs.
curve predicted by the and models differs for various geometries. The
results are compared with recent experiments, and predictions are made for
future experiments.Comment: 26 pages, with 6 figure
model of superconducting UPt
The phase diagram of superconducting UPt is explained in a
Ginzburg-Landau theory starting from the hypothesis that the order parameter is
a pseudo-spin singlet which transforms according to the representation
of the point group. We show how to compute the positions of the phase
boundaries both when the applied field is in the basal plane and when it is
along the c-axis. The experimental phase diagrams as determined by longitudinal
sound velocity data can be fit using a single set of parameters. In particular
the crossing of the upper critical field curves for the two field directions
and the apparent isotropy of the phase diagram are reproduced. The former is a
result of the magnetic properties of UPt and their contribution to the free
energy in the superconducting state. The latter is a consequence of an
approximate particle-hole symmetry. Finally we extend the theory to finite
pressure and show that, in contrast to other models, the model
explains the observed pressure dependence of the phase boundaries.Comment: RevTex, 29 pages, 18 PostScript figures in a uuencoded, gzipped tar
file. PostScript version of paper, tar file of PostScript figures and
individual PostScript figures are also available via anonymous ftp at
ftp://nym.physics.wisc.edu/anonymou/papers/upt3
Unconventional Pairing in Heavy Fermion Metals
The Fermi-liquid theory of superconductivity is applicable to a broad range
of systems that are candidates for unconventional pairing. Fundamental
differences between unconventional and conventional anisotropic superconductors
are illustrated by the unique effects that impurities have on the
low-temperature transport properties of unconventional superconductors. For
special classes of unconventional superconductors the low-temperature transport
coefficients are {\it universal}, i.e. independent of the impurity
concentration and scattering phase shift. The existence of a universal limit
depends on the symmetry of the order parameter and is achieved at low
temperatures , where is the bandwidth
of the impurity induced Andreev bound states. In the case of UPt thermal
conductivity measurements favor an or ground state.
Measurements at ultra-low temperatures should distinguish different pairing
states.Comment: 8 pages in a LaTex (3.0) file plus 5 Figures in PostScript. To appear
in the Proceedings of the XXI International Conference on Low Temperature
Physics held in Prague, 8-14 August 199
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