Large magnetic circular dichroism in resonant inelastic x-ray scattering at the Mn L-edge of Mn-Zn ferrite

We report resonant inelastic x-ray scattering (RIXS) excited by circularly polarized x-rays on Mn-Zn ferrite at the Mn L2,3-resonances. We demonstrate that crystal field excitations, as expected for localized systems, dominate the RIXS spectra and thus their dichroic asymmetry cannot be interpreted in terms of spin-resolved partial density of states, which has been the standard approach for RIXS dichroism. We observe large dichroic RIXS at the L2-resonance which we attribute to the absence of metallic core hole screening in the insulating Mn-ferrite. On the other hand, reduced L3-RIXS dichroism is interpreted as an effect of longer scattering time that enables spin-lattice core hole relaxation via magnons and phonons occurring on a femtosecond time scale.Comment: 7 pages, 2 figures, http://link.aps.org/doi/10.1103/PhysRevB.74.17240

Identification of network modules by optimization of ratio association

We introduce a novel method for identifying the modular structures of a network based on the maximization of an objective function: the ratio association. This cost function arises when the communities detection problem is described in the probabilistic autoencoder frame. An analogy with kernel k-means methods allows to develop an efficient optimization algorithm, based on the deterministic annealing scheme. The performance of the proposed method is shown on a real data set and on simulated networks

Brownian motion in a non-homogeneous force field and photonic force microscope

The Photonic Force Microscope (PFM) is an opto-mechanical technique based on an optical trap that can be assumed to probe forces in microscopic systems. This technique has been used to measure forces in the range of pico- and femto-Newton, assessing the mechanical properties of biomolecules as well as of other microscopic systems. For a correct use of the PFM, the force field to measure has to be invariable (homogeneous) on the scale of the Brownian motion of the trapped probe. This condition implicates that the force field must be conservative, excluding the possibility of a rotational component. However, there are cases where these assumptions are not fulfilled Here, we show how to improve the PFM technique in order to be able to deal with these cases. We introduce the theory of this enhanced PFM and we propose a concrete analysis workflow to reconstruct the force field from the experimental time-series of the probe position. Furthermore, we experimentally verify some particularly important cases, namely the case of a conservative or rotational force-field

Research and applications: Artificial intelligence

The program is reported for developing techniques in artificial intelligence and their application to the control of mobile automatons for carrying out tasks autonomously. Visual scene analysis, short-term problem solving, and long-term problem solving are discussed along with the PDP-15 simulator, LISP-FORTRAN-MACRO interface, resolution strategies, and cost effectiveness

A Non-Sequential Representation of Sequential Data for Churn Prediction

We investigate the length of event sequence giving best predictions when using a continuous HMM approach to churn prediction from sequential data. Motivated by observations that predictions based on only the few most recent events seem to be the most accurate, a non-sequential dataset is constructed from customer event histories by averaging features of the last few events. A simple K-nearest neighbor algorithm on this dataset is found to give significantly improved performance. It is quite intuitive to think that most people will react only to events in the fairly recent past. Events related to telecommunications occurring months or years ago are unlikely to have a large impact on a customer’s future behaviour, and these results bear this out. Methods that deal with sequential data also tend to be much more complex than those dealing with simple nontemporal data, giving an added benefit to expressing the recent information in a non-sequential manner

Initial Validation of the Teacher-Created Empowering and Disempowering Motivational Climate Questionnaire in Physical Education

Purpose: Guided by Duda’s hierarchical conceptualization of the motivational climate that draws from self-determination and achievement goal theories, this study provides initial evidence of the psychometric properties of the Empowering and Disempowering Motivational Climate Questionnaire in physical education (EDMCQ-PE). Method: Questionnaire based with two samples of Welsh secondary school pupils. Results: Exploratory structural equation modeling provided a better fit of the data to the hypothesized model than confirmatory factor analysis. Moreover, a two-factor composite (i.e., empowering and disempowering) lower-order model provided an acceptable fit and clear parameter estimates. This two-factor model also demonstrated scalar gender measurement invariance. Discussion: The evidence from this study suggests the EDMCQ-PE is a promising scale for the assessment of secondary school pupils’ perceptions of the empowering and disempowering features of the motivational climate created by their physical education teachers. Conclusion: Moving forward, the statistical approach employed in this paper can inform future studies that develop questionnaire methodology in physical education and from an applied perspective; the EDMCQ-PE can be used by researchers and teachers to assess the motivational climate in PE and help inform the pedagogy underpinning teachers’ classes

Fractal Descriptors in the Fourier Domain Applied to Color Texture Analysis

The present work proposes the development of a novel method to provide descriptors for colored texture images. The method consists in two steps. In the first, we apply a linear transform in the color space of the image aiming at highlighting spatial structuring relations among the color of pixels. In a second moment, we apply a multiscale approach to the calculus of fractal dimension based on Fourier transform. From this multiscale operation, we extract the descriptors used to discriminate the texture represented in digital images. The accuracy of the method is verified in the classification of two color texture datasets, by comparing the performance of the proposed technique to other classical and state-of-the-art methods for color texture analysis. The results showed an advantage of almost 3% of the proposed technique over the second best approach.Comment: Chaos, Volume 21, Issue 4, 201

An Investigation of Coach Behaviors, Goal Motives, and Implementation Intentions as Predictors of Well-Being in Sport

The present study aimed to expand upon Smith, Ntoumanis, and Duda’s (2007) research by investigating the influence of coach behaviors and implementation intentions on goal striving in sport. Structural equation modeling analysis with a sample of 108 athletes revealed coach behaviors as predictors of goal motives, which in turn predicted psychological well-being after 8 weeks. Supplementary regression analyses showed no interaction between autonomous goal motives and implementation intentions; however, a synergistic effect was identified for controlled goal motives such that controlled motives furnished with implementation intentions resulted in lower well-being than controlled motives alone. In further analyses, the motives underlying an implementation intention were found to mediate the paths from goal motives to well-being. The findings are discussed in terms of the roles played by goal motives, implementation intentions, and implementation intention motives during goal striving

Designing fuzzy rule based classifier using self-organizing feature map for analysis of multispectral satellite images

We propose a novel scheme for designing fuzzy rule based classifier. An SOFM based method is used for generating a set of prototypes which is used to generate a set of fuzzy rules. Each rule represents a region in the feature space that we call the context of the rule. The rules are tuned with respect to their context. We justified that the reasoning scheme may be different in different context leading to context sensitive inferencing. To realize context sensitive inferencing we used a softmin operator with a tunable parameter. The proposed scheme is tested on several multispectral satellite image data sets and the performance is found to be much better than the results reported in the literature.Comment: 23 pages, 7 figure

Empowering youth sport environments: Implications for daily moderate-to-vigorous physical activity and adiposity

AbstractBackgroundEvidence suggests involvement in youth sport does not guarantee daily guidelines for moderate-to-vigorous physical activity (MVPA) are met, and participation may not mitigate the risks associated with physical inactivity. The need to promote higher habitual MVPA engagement amongst children active in the youth sport context has therefore been underlined. Framed by self-determination theory, the aim of the present study was to examine the implications of the motivational climate created in youth sport, for children's daily engagement in MVPA and associated adiposity. Specifically, we sought to test a motivational sequence in which children's perceptions of an empowering coach-created motivational climate were related to autonomous and controlled motivation, which in turn predicted sport-related enjoyment. Finally, enjoyment is assumed to predict accelerometer assessed daily MVPA and, following this, adiposity.MethodsMale and female youth sport participants aged 9–16 years (n = 112) completed multi-section questionnaires assessing their perceptions of the motivational climate created in youth sport (i.e., autonomy supportive, task involving, socially supportive), autonomous and controlled motivation, and sport-related enjoyment. Daily MVPA engagement was determined via 7 days of accelerometry. Percent body fat (BF%) was estimated using bio-electrical impedance analysis.ResultsPath analysis revealed perceptions of an empowering motivational climate positively predicted players' autonomous motivation, and in turn, sport-related enjoyment. Enjoyment was also significantly negatively related to players' BF%, via a positive association with daily MVPA.ConclusionFostering more empowering youth sport environments may hold implications for the prevention of excess adiposity, through encouraging higher habitual MVPA engagement. Findings may inform the optimal design of youth sport settings for MVPA promotion, and contribute towards associated healthy weight maintenance amongst youth active in this context. Longitudinal and intervention studies are required to confirm these results