509 research outputs found
Elastic Properties and Magnetic Phase Diagrams of Dense Kondo Compound Ce0.75La0.25B6
We have investigated the elastic properties of the cubic dense Kondo compound
Ce0.75La0.25B6 by means of ultrasonic measurements. We have obtained magnetic
fields vs temperatures (H-T) phase diagrams under magnetic fields along the
crystallographic [001], [110] and [111] axes. An ordered phase IV showing the
elastic softening of c44 locates in low temperature region between 1.6 and 1.1
K below 0.7 T in all field directions. The phase IV shows an isotropic nature
with regard to the field directions, while the antiferro-magnetic phase III
shows an anisotropic character. A remarkable softening of c44 and a spontaneous
trigonal distortion εyz+εzx+εxy recently reported by Akatsu et
al. [J. Phys. Soc. Jpn. 72 (2003) 205] in the phase IV favor a ferro-quadrupole
(FQ) moment of Oyz+Ozx+Oxy induced by an octupole ordering.Comment: 9 figures, Strongly Correlated Electron
Magnetic edge states of impenetrable stripe
The electron motion in a strong perpendicular magnetic field close to the
impenetrable stripe is considered by making use of the singular integral
equation technique. The energy spectrum is calculated and compared with the
energy spectrum of the round antidot.Comment: REVTeX4 format, 9 pages with 9 figures (*.eps
Critical Phenomena at the Antiferromagnetic Phase Transition of Azurite
We report on high-resolution acoustic, specific-heat and thermal expansion
measurements in the vicinity of the antiferromagnetic phase transition at T_N =
1.88 K on a high-quality single crystal of the natural mineral azurite. A
detailed investigation of the critical contribution to the various quantities
at T_N is presented. The set of critical exponents and amplitude ratios of the
singular contributions above and below the transition indicate that the system
can be reasonably well described by a three-dimensional Heisenberg
antiferromagnet.Comment: 9 pages, 3 figures, proceedings of ICM 2012, JKP
Ultrasound Investigations of Orbital Quadrupolar Ordering in UPd_3
For a high-quality single crystal of UPd_3 we present the relevant elastic
constants and ultrasonic attenuation data. In addition to the magnetic phase
transition at T_2=4.4 +/- 0.1K and the quadrupolar transition at T_1~6.8K, we
find orbital ordering at T_0=7.6 +/- 0.1K concomitant with a symmetry change
from hexagonal to orthorhombic. A striking feature is the splitting of the
phase transition at T_1 into a second-order transition at T_{+1}=6.9 +/- 0.05K
and a first-order transition at T_{-1}=6.7 +/- 0.05K. For the four phase
transitions, the quadrupolar order parameters and the respective symmetry
changes are specified.Comment: 14 pages (RevTex), 3 eps-figures, accepted by PR
Continuous mode cooling and phonon routers for phononic quantum networks
We study the implementation of quantum state transfer protocols in phonon
networks, where in analogy to optical networks, quantum information is
transmitted through propagating phonons in extended mechanical resonator arrays
or phonon waveguides. We describe how the problem of a non-vanishing thermal
occupation of the phononic quantum channel can be overcome by implementing
optomechanical multi- and continuous mode cooling schemes to create a 'cold'
frequency window for transmitting quantum states. In addition, we discuss the
implementation of phonon circulators and switchable phonon routers, which rely
on strong coherent optomechanical interactions only, and do not require strong
magnetic fields or specific materials. Both techniques can be applied and
adapted to various physical implementations, where phonons coupled to spin or
charge based qubits are used for on-chip networking applications.Comment: 33 pages, 8 figures. Final version, a few minor changes and updated
reference
Measurement Properties of ID-PALL, A New Instrument for the Identification of Patients With General and Specialized Palliative Care Needs.
To improve access to palliative care, identification of patients in need of general or specialized palliative care is necessary. To our knowledge, no available identification instrument makes this distinction. ID-PALL is a screening instrument developed to differentiate between these patient groups.
To assess the structural and criterion validity and the inter-rater agreement of ID-PALL.
In this multicenter, prospective, cross-sectional study, nurses and physicians assessed medical patients hospitalized for 2 to 5 days in two tertiary hospitals in Switzerland using ID-PALL. For the criterion validity, these assessments were compared to a clinical gold standard evaluation performed by palliative care specialists. Structural validity, internal consistency and inter-rater agreement were assessed.
2232 patients were assessed between January and December 2018, 97% by nurses and 50% by physicians. The variances for ID-PALL G and S are explained by two factors, the first one explaining most of the variance in both cases. For ID-PALL G, sensitivity ranged between 0.80 and 0.87 and specificity between 0.56 and 0.59. ID-PALL S sensitivity ranged between 0.82 and 0.94, and specificity between 0.35 and 0.64. A cut-off value of 1 delivered the optimal values for patient identification. Cronbach's alpha was 0.78 for ID-PALL G and 0.67 for ID-PALL S. The agreement rate between nurses and physicians was 71.5% for ID-PALL G and 64.6% for ID-PALL S.
ID-PALL is a promising screening instrument allowing the early identification of patients in need of general or specialized palliative care. It can be used by nurses and physicians without a specialized palliative care training. Further testing of the finalized clinical version appears warranted
Impact of an interdisciplinary strategy on antibiotic use: a prospective controlled study in three hospitals
Objectives: Evaluation of the impact of the implementation of practice guidelines, with or without their reinforcement by a pharmacist, on the intra-hospital use of antibiotics. Materials and methods: The duration of antibiotic treatment, their cost, and the length of patient stay were compared in three secondary-care hospitals, before and after interventions that were designed to promote rational antibiotic use. After randomization, hospital A received no intervention (control), local practice guidelines were implemented in hospital B (low grade intervention), and these guidelines were reinforced by a clinical pharmacist in hospital C (high grade intervention). Adherence to the guidelines was measured in hospitals B and C. Multivariable statistical analyses were carried out to adjust for confounding factors. Results: None of the outcomes measured in the 1200 included patients decreased between the two study periods in any hospital. Hospital A was significantly and independently associated with an increase in the duration of antibiotic treatments, the cost of antibiotics (acquisition and global costs), and the length of stay. Although these differences were not statistically significant, increases in hospital B were higher than in hospital C. Adherence to guidelines was significantly higher in hospital C. Conclusions: Even though interdisciplinary interventions aiming at rationalizing antibiotic use could not diminish the duration of treatments, their costs or the length of stay, they proved useful to control the progression of these parameter
Anomalous elastic softening of SmRu_{4}P_{12} under high pressure
The filled skutterudite compound SmRu_4P_{12} undergoes a complex evolution
from a paramagnetic metal (phase I) to a probable multipolar ordering insulator
(phase II) at T_{MI} = 16.5 K, then to a magnetically ordered phase (phase III)
at T_{N} = 14 K. Elastic properties under hydrostatic pressures were
investigated to study the nature of the ordering phases. We found that distinct
elastic softening above T_{MI} is induced by pressure, giving evidence of
quadrupole degeneracy of the ground state in the crystalline electric field. It
also suggests that quadrupole moment may be one of the order parameters below
T_{MI} under pressure. Strangely, the largest degree of softening is found in
the transverse elastic constant C_{T} at around 0.5-0.6 GPa, presumably having
relevancy to the competing and very different Gruneisen parameters \Omega of
T_{MI} and T_{N}. Interplay between the two phase transitions is also verified
by the rapid increase of T_{MI} under pressure with a considerably large \Omega
of 9. Our results can be understood on the basis of the proposed octupole
scenario for SmRu_4P_{12}.Comment: 7 pages, 7 figure
Geometrical quadrupolar frustration in DyB
Physical properties of DyB have been studied by magnetization, specific
heat, and ultrasonic measurements. The magnetic entropy change and the
ultrasonic properties in the intermediate phase II indicate that the degeneracy
of internal degrees of freedom is not fully lifted in spite of the formation of
magnetic order. The ultrasonic attenuation and the huge softening of
in phase II suggests existence of electric-quadrupolar (orbital) fluctuations
of the 4-electron. These unusual properties originate from the geometrical
quadrupolar frustration.Comment: 4 pages, 4 figures, accepted for publication in Journal of the
Physical Society of Japa
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