611 research outputs found
Inelastic Multiple Scattering of Interacting Bosons in Weak Random Potentials
We develop a diagrammatic scattering theory for interacting bosons in a
three-dimensional, weakly disordered potential. We show how collisional energy
transfer between the bosons induces the thermalization of the inelastic
single-particle current which, after only few collision events, dominates over
the elastic contribution described by the Gross-Pitaevskii ansatz.Comment: 5 pages, 3 figures, very close to published versio
Stochastic Resonance: influence of a noise spectrum
Here, in order to study \textit{stochastic resonance} (SR) in a double-well
potential when the noise source has a spectral density of the form
with varying , we have extended a procedure, introduced
by Kaulakys et al (Phys. Rev. E \textbf{70}, 020101 (2004)). In order to have
an analytical understanding of the results, we have obtained an effective
Markovian approximation, that allows us to make a systematic study of the
effect of such kind of noises on the SR phenomenon. The comparison of numerical
and analytical results shows an excellent qualitative agreement indicating that
the effective Markovian approximation is able to correctly describe the general
trends.Comment: 11 pages, 6 figures, submitted to Euro.Phys.J.
Diagrammatic approach to coherent backscattering of laser light by cold atoms: Double scattering revisited
We present a diagrammatic derivation of the coherent backscattering spectrum
from two two-level atoms using the pump-probe approach, wherein the multiple
scattering signal is deduced from single-atom responses, and provide a physical
interpretation of the single-atom building blocks.Comment: 16 pages, 7 figure
Optimal Lewenstein-Sanpera Decomposition for some Biparatite Systems
It is shown that for a given bipartite density matrix and by choosing a
suitable separable set (instead of product set) on the separable-entangled
boundary, optimal Lewenstein-Sanpera (L-S) decomposition can be obtained via
optimization for a generic entangled density matrix. Based on this, We obtain
optimal L-S decomposition for some bipartite systems such as and
Bell decomposable states, generic two qubit state in Wootters
basis, iso-concurrence decomposable states, states obtained from BD states via
one parameter and three parameters local operations and classical
communications (LOCC), Werner and isotropic states, and a one
parameter state. We also obtain the optimal decomposition for
multi partite isotropic state. It is shown that in all systems
considered here the average concurrence of the decomposition is equal to the
concurrence. We also show that for some Bell decomposable states
the average concurrence of the decomposition is equal to the lower bound of the
concurrence of state presented recently in [Buchleitner et al,
quant-ph/0302144], so an exact expression for concurrence of these states is
obtained. It is also shown that for isotropic state where
decomposition leads to a separable and an entangled pure state, the average
I-concurrence of the decomposition is equal to the I-concurrence of the state.
Keywords: Quantum entanglement, Optimal Lewenstein-Sanpera decomposition,
Concurrence, Bell decomposable states, LOCC}
PACS Index: 03.65.UdComment: 31 pages, Late
Registered nurses in expanded roles improve care in nursing homes: Swiss perspective based on the modified Delphi method
To define both competencies and envisaged outcomes for registered nurses in expanded roles in Swiss nursing homes to be implemented and evaluated within a new model of care.; In regions where Advanced Practice Nurses are rare or absent, registered nurses take up clinical leadership and expanded roles. To allow effective implementation, monitoring and evaluation of these nurses, stakeholders need a shared understanding of the competencies they require and what outcomes they should achieve.; RAND/UCLA Appropriateness Method - a modified Delphi method.; A critical literature review and case studies were conducted to identify possible competencies and outcomes for registered nurses in expanded roles. In 2017, a two-round rating process and an in-person panel discussion was completed by a group of multi-professional stakeholders.; Two rounds generated 190 competencies and 72 outcomes relevant to registered nurses in expanded roles.; The relevant competencies and outcomes of registered nurses in expanded roles indicate their support for care teams and development of nursing care in nursing homes. Their geriatric expertise allows them to function as role models and innovators, reinforcing overall perceptions of nursing as a profession. These nurses are especially important in countries and settings where Advanced Practice Nurses are scarce or unavailable.; The identified competencies clarify the duties of expanded-role registered nurses, thereby differentiating them from other care providers. Although conducted in the Swiss healthcare system, our methods and findings can be adapted to other healthcare settings. The results of this study will guide the development of an educational programme in a multi-centre study to reduce avoidable hospitalizations, while the defined outcomes guide the evaluation of their impact
Diffractive Backside Structures via Nanoimprint Lithography
AbstractFor decreasing thicknesses of wafer based silicon solar cells, photon management structures to maintain high quantum efficiencies will gain importance. Diffractive gratings on the wafer back side can be designed to achieve very high path length enhancements, especially for weakly absorbed infrared radiation. This technologically demanding concept has to be realised using processes with upscaling potential. Therefore, we present a fabrication process for producing photonic structures in silicon based on interference lithography and nanoimprint lithography (NIL).We realised linear as well as crossed gratings of different depths, which were etched into the wafer back side. Polarisation dependent reflection measurements were made to get information about potential absorption enhancement as well as the occurrence of parasitic absorption in the metal reflector. This is conducted for a PECVD silicon oxide buffer layer between grating and reflector as well as a spin coated silicon oxide layer. Besides these optical characterisations, we further investigated the electrical properties of the back surface, where we applied a concept in which electrical and optical properties are decoupled. This is realised by a layer stack on the wafer back side, consisting of a thin Al2O3 passivation and a doped amorphous silicon layer
The interRAI Acute Care instrument incorporated in an eHealth system for standardized and web-based geriatric assessment: strengths, weaknesses, opportunities and threats in the acute hospital setting
BACKGROUND: The interRAI Acute Care instrument is a multidimensional geriatric assessment system intended to determine a hospitalized older personsâ medical, psychosocial and functional capacity and needs. Its objective is to develop an overall plan for treatment and long-term follow-up based on a common set of standardized items that can be used in various care settings. A Belgian web-based software system (BelRAI-software) was developed to enable clinicians to interpret the output and to communicate the patientsâ data across wards and care organizations. The purpose of the study is to evaluate the (dis)advantages of the implementation of the interRAI Acute Care instrument as a comprehensive geriatric assessment instrument in an acute hospital context. METHODS: In a cross-sectional multicenter study on four geriatric wards in three acute hospitals, trained clinical staff (nurses, occupational therapists, social workers, and geriatricians) assessed 410 inpatients in routine clinical practice. The BelRAI-system was evaluated by focus groups, observations, and questionnaires. The Strengths, Weaknesses, Opportunities and Threats were mapped (SWOT-analysis) and validated by the participants. RESULTS: The primary strengths of the BelRAI-system were a structured overview of the patientsâ condition early after admission and the promotion of multidisciplinary assessment. Our study was a first attempt to transfer standardized data between home care organizations, nursing homes and hospitals and a way to centralize medical, allied health professionals and nursing data. With the BelRAI-software, privacy of data is guaranteed. Weaknesses are the time-consuming character of the process and the overlap with other assessment instruments or (electronic) registration forms. There is room for improving the user-friendliness and the efficiency of the software, which needs hospital-specific adaptations. Opportunities are a timely and systematic problem detection and continuity of care. An actual shortage of funding of personnel to coordinate the assessment process is the most important threat. CONCLUSION: The BelRAI-software allows standardized transmural information transfer and the centralization of medical, allied health professionals and nursing data. It is strictly secured and follows strict privacy regulations, allowing hospitals to optimize (transmural) communication and interaction. However, weaknesses and threats exist and must be tackled in order to promote large scale implementation
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