89 research outputs found

    Modeling and optimization of high-power Nd3+-Yb3+ codoped fiber lasers

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    Ethical and Practical Issues in Video Surveillance of Psychiatric Units

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    Objectives: Video surveillance is used in inpatient psychiatry in many countries and institutions. However, its use varies considerably because of a lack of research, discussion, and agreement on best practice. This review provides an overview of current issues in the use of video surveillance in psychiatry, with a focus on ethical questions and their practical implications. Methods: A narrative review of literature on video surveillance in psychiatry was conducted. References were identified through searches of PubMed, CINAHL, MEDLINE, PsycINFO, and Google Scholar for articles published before December 2018. Sixteen articles in English and German were reviewed. Results: The ethical challenges and practical implications differ between surveillance of public spaces versus private areas, such as bedrooms or seclusion rooms. The most common reason for video surveillance was to increase security and safety. However, empirical evidence suggests that it is not useful in increasing security of shared spaces on psychiatric wards. Some evidence exists for clinical benefits of video surveillance in private spaces (e.g., allowing patients to sleep undisturbed). Video surveillance can increase patients’ choices regarding monitoring options. The main ethical conflict lies in balancing patients’ autonomy and privacy versus patient and staff security and safety. Conclusions: Whether video monitoring is used in the most effective and ethical manner needs to be reconsidered. Available evidence does not support its use as a security measure. More research is needed to evaluate the benefits, risks, and best practices of using video monitoring for patient observation, with consideration given to increasing the role of patient consent

    Dynamics of executive functions, basic psychological needs, impulsivity, and depressive symptoms in american football players

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    Executive functions play an important role in sports since the ability to plan, organize, and regulate behavior to reach an objective or goal depends on these functions. Some of the components of executive functions, such as inhibition of impulsive behavior and cognitive flexibility, are necessary for contact sports (e.g., American football) to carry out successful plays on the sports field. Executive functions have been studied in the sporting environment, but their relationship with the athletes' basic psychological needs (BPN), such as autonomy, competence, and relatedness, remains unexplored. Due to the importance of motivational processes over cognitive functions and in the generated adaptive results in athletes, this relationship should be taken into account. Therefore, the aim of this study was to analyze and compare executive functioning and psychological need thwarting overimpulsivity and psychological distress, before and after the season (4 months) in 28 undergraduate football players. Neuropsychological and psychological tests were applied. The results showed that there was an improvement in inhibition and planning at the end of the season. There was also an increase in attention and motor impulsiveness, and a decrease in need thwarting at the end of the season. A positive association between executive function, impulsiveness, psychological needs, and affective symptoms were also found. Our findings reveal the dynamics of sport-related psychological variables throughout the sport season in American football players, the association of these for the achievement of sport success, and the importance of encouraging proper management of emotions

    Dynamics of Executive Functions, Basic Psychological Needs, Impulsivity, and Depressive Symptoms in American Football Players

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    Executive functions play an important role in sports since the ability to plan, organize,and regulate behavior to reach an objective or goal depends on these functions. Someof the components of executive functions, such as inhibition of impulsive behavior andcognitive flexibility, are necessary for contact sports (e.g., American football) to carryout successful plays on the sports field. Executive functions have been studied in thesporting environment, but their relationship with the athletes’ basic psychological needs(BPN), such as autonomy, competence, and relatedness, remains unexplored. Due tothe importance of motivational processes over cognitive functions and in the generatedadaptive results in athletes, this relationship should be taken into account. Therefore, theaim of this study was to analyze and compare executive functioning and psychologicalneed thwarting overimpulsivity and psychological distress, before and after the season(4 months) in 28 undergraduate football players. Neuropsychological and psychologicaltests were applied. The results showed that there was an improvement in inhibitionand planning at the end of the season. There was also an increase in attention andmotor impulsiveness, and a decrease in need thwarting at the end of the season.A positive association between executive function, impulsiveness, psychological needs,and affective symptoms were also found. Our findings reveal the dynamics of sport-related psychological variables throughout the sport season in American football players,the association of these for the achievement of sport success, and the importance ofencouraging proper management of emotions

    Observation of the screening signature in the lateral photovoltage of electrons in the Quantum Hall regime

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    The lateral photovoltage generated in the plane of a two-dimensional electron system (2DES) by a focused light spot, exhibits a fine-structure in the quantum oscillations in a magnetic field near the Quantum Hall conductivity minima. A double peak structure occurs near the minima of the longitudinal conductivity oscillations. This is the characteristic signature of the interplay between screening and Landau quantization.Comment: 4 pages, 4 figures, to be published in Phys. Rev.

    Quantization of the Hall conductivity well beyond the adiabatic limit in pulsed magnetic fields

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    We measure the Hall conductivity, σxy\sigma_{xy}, on a Corbino geometry sample of a high-mobility AlGaAs/GaAs heterostructure in a pulsed magnetic field. At a bath temperature about 80 mK, we observe well expressed plateaux in σxy\sigma_{xy} at integer filling factors. In the pulsed magnetic field, the Laughlin condition of the phase coherence of the electron wave functions is strongly violated and, hence, is not crucial for σxy\sigma_{xy} quantization.Comment: 4 pages, 4 figures, submitted to PR

    Electrostatics of Inhomogeneous Quantum Hall Liquid

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    The distribution of electron density in the quantum Hall liquid is considered in the presence of macroscopic density gradient caused by side electrodes or inhomogeneous doping. In this case different Landau levels are occupied in different regions of a sample. These regions are separated by incompressible liquid. It is shown that the applicability of the approach by Chklovskii et al. is substantially restricted if the density gradient is not very large and disorder is important. Due to the fluctuations of the remote donor's density the liquid in the transition region can not be considered as completely incompressible. In the typical situation, when the gap between Landau levels is not much larger than the energy of disorder, the transition region is a wide band where electron density, averaged over the fluctuations, is independent of magnetic field. The band is a random mixture of regions occupied by electrons of upper level, by holes of lower level and by incompressible liquid. The width of this band is calculated and an analytical expression for the fraction of incompressible liquid in different parts of this band is given.Comment: 12 pages, RevTe

    Self-consistent local-equilibrium model for density profile and distribution of dissipative currents in a Hall bar under strong magnetic fields

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    Recent spatially resolved measurements of the electrostatic-potential variation across a Hall bar in strong magnetic fields, which revealed a clear correlation between current-carrying strips and incompressible strips expected near the edges of the Hall bar, cannot be understood on the basis of existing equilibrium theories. To explain these experiments, we generalize the Thomas-Fermi--Poisson approach for the self-consistent calculation of electrostatic potential and electron density in {\em total} thermal equilibrium to a {\em local equilibrium} theory that allows to treat finite gradients of the electrochemical potential as driving forces of currents in the presence of dissipation. A conventional conductivity model with small values of the longitudinal conductivity for integer values of the (local) Landau-level filling factor shows that, in apparent agreement with experiment, the current density is localized near incompressible strips, whose location and width in turn depend on the applied current.Comment: 9 pages, 7 figure

    A model for cyclotron resonance scattering features

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    (abbreviated version of the abstract) We study the physics of cyclotron line formation in the high-energy spectra of accreting X-ray pulsars using Monte Carlo methods, assuming that the line-forming region is a low-density electron plasma in a sub-critical magnetic field. We investigate the dependence of the shape of the fundamental line on angle, geometry, optical depth and temperature. We also discuss variations of the line ratios for non-uniform magnetic fields. These numerical predictions for the line profiles are linked to results from observational data analysis using an XSPEC model based on the Monte Carlo simulations. We apply this model to observational data from RXTE and INTEGRAL. The predicted strong emission wings of the fundamental cyclotron feature are not found in observational data, hinting at a bottom illuminated slab geometry for line formation.Comment: 16 pages, 15 figures, Astron. Astrophys. (in press
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