2,326 research outputs found
Ergodic vs diffusive decoherence in mesoscopic devices
We report on the measurement of phase coherence length in a high mobility
two-dimensional electron gas patterned in two different geometries, a wire and
a ring. The phase coherence length is extracted both from the weak localization
correction in long wires and from the amplitude of the Aharonov-Bohm
oscillations in a single ring, in a low temperature regime when decoherence is
dominated by electronic interactions. We show that these two measurements lead
to different phase coherence lengths, namely and . This difference
reflects the fact that the electrons winding around the ring necessarily
explore the whole sample (ergodic trajectories), while in a long wire the
electrons lose their phase coherence before reaching the edges of the sample
(diffusive regime).Comment: LaTeX, 5 pages, 4 pdf figures ; v2: revised versio
Integer and fractional charge Lorentzian voltage pulses analyzed in the frame of Photon-assisted Shot Noise
The periodic injection of electrons in a quantum conductor using periodic
voltage pulses applied on a contact is studied in the energy and time-domain
using shot noise computation in order to make comparison with experiments. We
particularly consider the case of periodic Lorentzian voltage pulses. When
carrying integer charge, they are known to provide electronic states with a
minimal number of excitations, while other type of pulses are all accompanied
by an extra neutral cloud of electron and hole excitations. This paper focuses
on the low frequency shot noise which arises when the pulse excitations are
partitioned by a single scatterer in the framework of the Photo Assisted Shot
Noise (PASN) theory. As a unique tool to count the number of excitations
carried per pulse, shot noise reveals that pulses of arbitrary shape and
arbitrary charge show a marked minimum when the charge is integer. Shot noise
spectroscopy is also considered to perform energy-domain characterization of
the charge pulses. In particular it reveals the striking asymmetrical spectrum
of Lorentzian pulses. Finally, time-domain information is obtained from Hong Ou
Mandel like noise correlations when two trains of pulses generated on opposite
contacts collide on the scatterer. As a function of the time delay between
pulse trains, the noise is shown to measure the electron wavepacket
autocorrelation function for integer Lorentzian thanks to electron
antibunching. In order to make contact with recent experiments all the
calculations are made at zero and finite temperature
Identity Regulation, Identity Work and Phronesis
How do corporations attempt to regulate the ways middle managers draw on discourses centred on 'effectiveness' and 'ethics' in their identity work, and how do these individuals respond? We analyse the discursive struggle over what it meant to be a competent manager at Disneyland where middle managers were encouraged to construe their selves in ways which emphasized ‘being effective’ over ‘being ethical’, and managers responded with identity work which positioned them as searching for the practical wisdom (phronesis) to make decisions that were both effective and moral. The theoretical contribution we make is twofold. First, we analyse processes of identity regulation and identity work at Disneyland, highlighting divergences between corporate injunctions and middle managers appropriations of them, regarding what it meant to be a practically wise manager. Second, we discuss a phronetic identity narrative template, contestable both by organizations and managers, in which people are positioned as questing for the practical wisdom to make decisions that are both moral and effective, and phronesis as an image by which scholars may analyse identities and identity work. This leads us to a more nuanced understanding of middle manager identities and the scope they have to constitute their selves as moral agents
EFFECTS OF ZOLEDRONATE ON TWO- AND THREE-DIMENSIONAL OSTEOBLAST CULTURES
Oral Communication presented at the ";;Forum des Jeunes Chercheurs";;, Brest (France) 2011
Quantum Coherence at Low Temperatures in Mesoscopic Systems: Effect of Disorder
We study the disorder dependence of the phase coherence time of quasi
one-dimensional wires and two-dimensional (2D) Hall bars fabricated from a high
mobility GaAs/AlGaAs heterostructure. Using an original ion implantation
technique, we can tune the intrinsic disorder felt by the 2D electron gas and
continuously vary the system from the semi-ballistic regime to the localized
one. In the diffusive regime, the phase coherence time follows a power law as a
function of diffusion coefficient as expected in the Fermi liquid theory,
without any sign of low temperature saturation. Surprisingly, in the
semi-ballistic regime, it becomes independent of the diffusion coefficient. In
the strongly localized regime we find a diverging phase coherence time with
decreasing temperature, however, with a smaller exponent compared to the weakly
localized regime.Comment: 21 pages, 30 figure
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Real-Time Face Pose Estimation from Single Range Images
We present a real-time algorithm to estimate the 3D pose of a previously unseen face from a single range image. Based on a novel shape signature to identify noses in range images, we generate candidates for their positions, and then generate and evaluate many pose hypotheses in parallel using modern graphics processing units (GPUs). We developed a novel error function that compares the input range image to precomputed pose images of an average face model. The algorithm is robust to large pose variations of plusmn90deg yaw, plusmn45deg pitch and plusmn30deg roll rotation, facial expression, partial occlusion, and works for multiple faces in the field of view. It correctly estimates 97.8% of the poses within yaw and pitch error of 15deg at 55.8 fps. To evaluate the algorithm, we built a database of range images with large pose variations and developed a method for automatic ground truth annotation.Engineering and Applied Science
A systematic review of patient safety in mental health: a protocol based on the inpatient setting
BACKGROUND: Despite the growing international interest in patient safety as a discipline, there has been a lack of exploration of its application to mental health. It cannot be assumed that findings based upon physical health in acute care hospitals can be applied to mental health patients, disorders and settings. To the authors' knowledge, there has only been one review of the literature that focuses on patient safety research in mental health settings, conducted in Canada in 2008. We have identified a need to update this review and develop the methodology in order to strengthen the findings and disseminate internationally for advancement in the field. This systematic review will explore the existing research base on patient safety in mental health within the inpatient setting. METHODS: To conduct this systematic review, a thorough search across multiple databases will be undertaken, based upon four search facets ("mental health", "patient safety", "research" and "inpatient setting"). The search strategy has been developed based upon the Canadian review accompanied with input from the National Reporting and Learning System (NRLS) taxonomy of patient safety incidents and the Diagnostic and Statistical Manual of Mental Disorders (fifth edition). The screening process will involve perspectives from at least two researchers at all stages with a third researcher invited to review when discrepancies require resolution. Initial inclusion and exclusion criteria have been developed and will be refined iteratively throughout the process. Quality assessment and data extraction of included articles will be conducted by at least two researchers. A data extraction form will be developed, piloted and iterated as necessary in accordance with the research question. Extracted information will be analysed thematically. DISCUSSION: We believe that this systematic review will make a significant contribution to the advancement of patient safety in mental health inpatient settings. The findings will enable the development and implementation of interventions to improve the quality of care experienced by patients and support the identification of future research priorities. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016034057
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