2,082,674 research outputs found

    Triplet Josephson effect with magnetic feedback

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    We study AC Josephson effect in a superconductor-ferromagnet heterostructure with a variable magnetic configuration. The system supports triplet proximity correlations whose dynamics is coupled to the magnetic dynamics. This feedback dramatically modifies the behavior of the junction. The current-phase relation becomes double-periodic at both very low and high Josephson frequencies ωJ\omega_J. At intermediate frequencies, the periodicity in ωJt\omega_J t may be lost.Comment: 4 pages, 3 figure

    Particle entrapment as a feedback effect

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    We consider a suspension of polarizable particles under the action of traveling wave dielectrophoresis (DEP) and focus on particle induced effects. In a situation where the particles are driven by the DEP force, but no external forces are exerted on the fluid, the joint motion of the particles can induce a steady fluid flow, which leads to particle entrapment. This feedback effect is proven to be non-negligible even for small volume concentration of particles.Comment: 4 pages, 4 figures, submitte

    The Effect of Haptic Feedback on Basic Social. Interaction within Shared Virtual Environments

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    This paper describes an experiment that studies the effect of basic haptic feedback in creating a sense of social interaction within a shared virtual environment (SVE). Although there have been a number of studies investigating the effect of haptic feedback on collaborative task performance, they do not address the effect it has in inducing social presence. The purpose of this experiment is to show that haptic feedback enhances the sense of social presence within a mediated environment. An experiment was carried out using a shared desktop based virtual environment where 20 remotely located couples who did not know one another had to solve a puzzle together. In 10 groups they had shared haptic communication through their hands, and in another group they did not. Hence the haptic feedback was not used for completing the task itself, but rather as a means of social interacting – communicating with the other participant. The results suggest that basic haptic feedback increases the sense of social presence within the shared VE

    Physical Dissipation and the Method of Controlled Lagrangians

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    We describe the effect of physical dissipation on stability of equilibria which have been stabilized, in the absence of damping, using the method of controlled Lagrangians. This method applies to a class of underactuated mechanical systems including “balance” systems such as the pendulum on a cart. Since the method involves modifying a system’s kinetic energy metric through feedback, the effect of dissipation is obscured. In particular, it is not generally true that damping makes a feedback-stabilized equilibrium asymptotically stable. Damping in the unactuated directions does tend to enhance stability, however damping in the controlled directions must be “reversed” through feedback. In this paper, we suggest a choice of feedback dissipation to locally exponentially stabilize a class of controlled Lagrangian systems

    A nod in the wrong direction : Does nonverbal feedback affect eyewitness confidence in interviews?

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    Eyewitnesses can be influenced by an interviewer's behaviour and report information with inflated confidence as a result. Previous research has shown that positive feedback administered verbally can affect the confidence attributed to testimony, but the effect of non-verbal influence in interviews has been given little attention. This study investigated whether positive or negative non-verbal feedback could affect the confidence witnesses attribute to their responses. Participants witnessed staged CCTV footage of a crime scene and answered 20 questions in a structured interview, during which they were given either positive feedback (a head nod), negative feedback (a head shake) or no feedback. Those presented with positive non-verbal feedback reported inflated confidence compared with those presented with negative non-verbal feedback regardless of accuracy, and this effect was most apparent when participants reported awareness of the feedback. These results provide further insight into the effects of interviewer behaviour in investigative interviewsPeer reviewedFinal Accepted Versio

    Feedback and its Feedback Effect on Feedback: Photoionization Suppression and its Impact on Galactic Outflows

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    We show that radiative feedback due to reionization has a pronounced effect on the extent of mechanical feedback due to galactic outflows. The photoionization of the Intergalactic Medium (IGM) suppresses low-mass galaxy formation by photoheating the gas and limiting atomic line cooling. The number of low-mass galaxies is central for the enrichment of the IGM as these objects have the capacity to enrich a significant fraction (by volume) of the Universe. We use a modified version of our galactic outflow model, combined with a simple criterion for suppression, to investigate the potential impact upon the IGM. We find that this suppression strongly reduces the enrichment of the IGM and is sensitive to the reionization history. We also investigate the contribution of halos of different masses with varying degrees of suppression.Comment: 4 pages, 3 figures, class file included, accepted by ApJ Letters, minor changes and expanded Figure

    Is Bank Portfolio Riskiness Procyclical? Evidence from Italy using a Vector Autoregression

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    This study analyzes the cyclical behaviour of the default rates of Italian bank borrowers over the last two decades. A vector autoregression (VAR) modelling technique is employed to assess the extent to which macroeconomic shocks affect the banking sector (first round effect). The VAR also helps to disentangle the feedback effects from the financial system to the real side of the economy. We find evidence of the first round effect and some support for the feedback effect which operates via the bank capital channel.First-round effect; procyclicality; feedback effects; VAR; banks; default rate

    Routinely administered questionnaires for depression and anxiety : systematic review

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    Objectives To examine the effect of routinely administered psychiatric questionnaires on the recognition, management, and outcome of psychiatric disorders in non-psychiatric settings. Data sources Embase, Medline, PsycLIT, Cinahl, Cochrane Controlled Trials Register,and hand searches of key journals. Methods A systematic review of randomised controlled trials of the administration and routine feedback of psychiatric screening and outcome questionnaires to clinicians in non-psychiatric settings. narrative overview of key design features and end points, together with a random effects quantitative synthesis of comparable studies. Main outcome measures Recognition of psychiatric disorders after feedback of questionnaire results; interventions for psychiatric disorders and outcome of psychiatric disorders. Results Nine randomised studies were identified that examined the use of common psychiatric instruments in primary care and general hospital settings. Studies compared the effect of the administration of these instruments followed by the feedback of the results to clinicians, with administration with no feedback. Meta-analytic pooling was possible for four of these studies (2457 participants), which measured the effect of feedback on the recognition of depressive disorders. Routine administration and feedback of scores for all patients (irrespective of score) did not increase the overall rate of recognition of mental disorders such as anxiety and depression (relative risk of detection of depression by clinician after feedback 0.95, 95% confidence interval 0.83 to 1.09). Two studies showed that routine administration followed by selective feedback for only high scores increased the rate of recognition of depression (relative risk of detection of depression after feedback 2.64, 1.62 to 4.31). This increased recognition, however, did not translate into an increased rate of intervention. Overall, studies of routine administration of psychiatric measures did not show an effect on patient outcome. Conclusions The routine measurement of outcome is a costly exercise. Little evidence shows that it is of benefit in improving psychosocial outcomes of those with psychiatric disorder managed in non-psychiatric settings

    Cosmological Simulations of Dwarf Galaxies with Cosmic Ray Feedback

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    We perform zoom-in cosmological simulations of a suite of dwarf galaxies, examining the impact of cosmic-rays generated by supernovae, including the effect of diffusion. We first look at the effect of varying the uncertain cosmic ray parameters by repeatedly simulating a single galaxy. Then we fix the comic ray model and simulate five dwarf systems with virial masses range from 8-30 ×1010\times 10^{10} Msun. We find that including cosmic ray feedback (with diffusion) consistently leads to disk dominated systems with relatively flat rotation curves and constant star formation rates. In contrast, our purely thermal feedback case results in a hot stellar system and bursty star formation. The CR simulations very well match the observed baryonic Tully-Fisher relation, but have a lower gas fraction than in real systems. We also find that the dark matter cores of the CR feedback galaxies are cuspy, while the purely thermal feedback case results in a substantial core.Comment: 11 pages, 10 figures, MNRAS in pres
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