313 research outputs found
Relativistic nature of a magnetoelectric modulus of Cr_2O_3-crystals: a new 4-dimensional pseudoscalar and its measurement
Earlier, the magnetoelectric effect of chromium sesquioxide Cr_2O_3 has been
determined experimentally as a function of temperature. One measures the
electric field-induced magnetization on Cr_2O_3 crystals or the magnetic
field-induced polarization. From the magnetoelectric moduli of Cr_2O_3 we
extract a 4-dimensional relativistic invariant pseudoscalar
. It is temperature dependent and of the order of
10^{-4}/Z_0, with Z_0 as vacuum impedance. We show that the new pseudoscalar is
odd under parity transformation and odd under time inversion. Moreover,
is for Cr_2O_3 what Tellegen's gyrator is for two port
theory, the axion field for axion electrodynamics, and the PEMC (perfect
electromagnetic conductor) for electrical engineering.Comment: Revtex, 36 pages, 9 figures (submitted in low resolution, better
quality figures are available from the authors
Analogue Models for T and CPT Violation in Neutral-Meson Oscillations
Analogue models for CP violation in neutral-meson systems are studied in a
general framework. No-go results are obtained for models in classical mechanics
that are nondissipative or that involve one-dimensional oscillators. A complete
emulation is shown to be possible for a two-dimensional oscillator with
rheonomic constraints, and an explicit example with spontaneous T and CPT
violation is presented. The results have implications for analogue models with
electrical circuits.Comment: 9 page
Effects of music therapy in the treatment of children with delayed speech development - results of a pilot study
<p>Abstract</p> <p>Background</p> <p>Language development is one of the most significant processes of early childhood development. Children with delayed speech development are more at risk of acquiring other cognitive, social-emotional, and school-related problems. Music therapy appears to facilitate speech development in children, even within a short period of time. The aim of this pilot study is to explore the effects of music therapy in children with delayed speech development.</p> <p>Methods</p> <p>A total of 18 children aged 3.5 to 6 years with delayed speech development took part in this observational study in which music therapy and no treatment were compared to demonstrate effectiveness. Individual music therapy was provided on an outpatient basis. An ABAB reversal design with alternations between music therapy and no treatment with an interval of approximately eight weeks between the blocks was chosen. Before and after each study period, a speech development test, a non-verbal intelligence test for children, and music therapy assessment scales were used to evaluate the speech development of the children.</p> <p>Results</p> <p>Compared to the baseline, we found a positive development in the study group after receiving music therapy. Both phonological capacity and the children's understanding of speech increased under treatment, as well as their cognitive structures, action patterns, and level of intelligence. Throughout the study period, developmental age converged with their biological age. Ratings according to the Nordoff-Robbins scales showed clinically significant changes in the children, namely in the areas of client-therapist relationship and communication.</p> <p>Conclusions</p> <p>This study suggests that music therapy may have a measurable effect on the speech development of children through the treatment's interactions with fundamental aspects of speech development, including the ability to form and maintain relationships and prosodic abilities. Thus, music therapy may provide a basic and supportive therapy for children with delayed speech development. Further studies should be conducted to investigate the mechanisms of these interactions in greater depth.</p> <p>Trial registration</p> <p>The trial is registered in the German clinical trials register; Trial-No.: DRKS00000343</p
Effect of shunted piezoelectric control for tuning piezoelectric power harvesting system responses – Analytical techniques
This paper presents new analytical modelling of shunt circuit control responses for tuning electromechanical piezoelectric vibration power harvesting structures with proof mass offset. For this combination, the dynamic closed-form boundary value equations reduced from strong form variational principles were developed using the extended Hamiltonian principle to formulate the new coupled orthonormalised electromechanical power harvesting equations showing combinations of the mechanical system (dynamical behaviour of piezoelectric structure), electromechanical system (electrical piezoelectric response) and electrical system (tuning and harvesting circuits). The reduced equations can be further formulated to give the complete forms of new electromechanical multi-mode FRFs and time waveform of the standard AC-DC circuit interface. The proposed technique can demonstrate self-adaptive harvesting response capabilities for tuning the frequency band and the power amplitude of the harvesting devices. The self-adaptive tuning strategies are demonstrated by modelling the shunt circuit behaviour of the piezoelectric control layer in order to optimise the harvesting piezoelectric layer during operation under input base excitation. In such situations, with proper tuning parameters the system performance can be substantially improved. Moreover, the validation of the closed-form technique is also provided by developing the Ritz method-based weak form analytical approach giving similar results. Finally, the parametric analytical studies have been explored to identify direct and relevant contributions for vibration power harvesting behaviours
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Applied Personality Assessment: A 'Cronbachian' Perspective in Open Peer Commentary and Author's Response
Lievens's proposal that personality psychology would benefit from using applied tools of assessment—situation judgement tests and assessment centre exercises—was appropriate, especially as these tools focus on real-world criteria in high-stakes situations. Their use would help to integrate (specific) situationally influenced intra-individual differences (variability) and (general) inter-individual differences (diversity). Lievens's proposal also raised a broader issue: each assessment tool yields unique information, and together they have potential to provide a truly comprehensive model of personality based on the ‘Cronbachian’ perspective that has, so far, not been realized. Copyright © 2017 European Association of Personality Psycholog
Networks of Emotion Concepts
The aim of this work was to study the similarity network and hierarchical clustering of Finnish emotion concepts. Native speakers of Finnish evaluated similarity between the 50 most frequently used Finnish words describing emotional experiences. We hypothesized that methods developed within network theory, such as identifying clusters and specific local network structures, can reveal structures that would be difficult to discover using traditional methods such as multidimensional scaling (MDS) and ordinary cluster analysis. The concepts divided into three main clusters, which can be described as negative, positive, and surprise. Negative and positive clusters divided further into meaningful sub-clusters, corresponding to those found in previous studies. Importantly, this method allowed the same concept to be a member in more than one cluster. Our results suggest that studying particular network structures that do not fit into a low-dimensional description can shed additional light on why subjects evaluate certain concepts as similar. To encourage the use of network methods in analyzing similarity data, we provide the analysis software for free use (http://www.becs.tkk.fi/similaritynets/)
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