On the dc Magnetization, Spontaneous Vortex State and Specific Heat in the superconducting state of the weakly ferromagnetic superconductor RuSr2_{2}GdCu2_{2}O8_{8}

Magnetic-field changes $<$ 0.2 Oe over the scan length in magnetometers that necessitate sample movement are enough to create artifacts in the dc magnetization measurements of the weakly ferromagnetic superconductor RuSr$_{2}$GdCu$_{2}$O$_{8}$ (Ru1212) below the superconducting transition temperature $T_{c} \approx$ 30 K. The observed features depend on the specific magnetic-field profile in the sample chamber and this explains the variety of reported behaviors for this compound below $T_{c}$. An experimental procedure that combines improvement of the magnetic-field homogeneity with very small scan lengths and leads to artifact-free measurements similar to those on a stationary sample has been developed. This procedure was used to measure the mass magnetization of Ru1212 as a function of the applied magnetic field H (-20 Oe $\le$ H $\le$ 20 Oe) at $T < T_{c}$ and discuss, in conjunction with resistance and ac susceptibility measurements, the possibility of a spontaneous vortex state (SVS) for this compound. Although the existence of a SVS can not be excluded, an alternative interpretation of the results based on the granular nature of the investigated sample is also possible. Specific-heat measurements of Sr$_{2}$GdRuO$_{6}$ (Sr2116), the precursor for the preparation of Ru1212 and thus a possible impurity phase, show that it is unlikely that Sr2116 is responsible for the specific-heat features observed for Ru1212 at $T_{c}$.Comment: 17 pages, 6 figure

On Quadrirational Yang-Baxter Maps

We use the classification of the quadrirational maps given by Adler, Bobenko and Suris to describe when such maps satisfy the Yang-Baxter relation. We show that the corresponding maps can be characterized by certain singularity invariance condition. This leads to some new families of Yang-Baxter maps corresponding to the geometric symmetries of pencils of quadrics.Comment: Proceedings of the workshop "Geometric Aspects of Discrete and Ultra-Discrete Integrable Systems" (Glasgow, March-April 2009

A Trainable Object Detection System: Car Detection in Static Images

This paper describes a general, trainable architecture for object detection that has previously been applied to face and peoplesdetection with a new application to car detection in static images. Our technique is a learning based approach that uses a set of labeled training data from which an implicit model of an object class -- here, cars -- is learned. Instead of pixel representations that may be noisy and therefore not provide a compact representation for learning, our training images are transformed from pixel space to that of Haar wavelets that respond to local, oriented, multiscale intensity differences. These feature vectors are then used to train a support vector machine classifier. The detection of cars in images is an important step in applications such as traffic monitoring, driver assistance systems, and surveillance, among others. We show several examples of car detection on out-of-sample images and show an ROC curve that highlights the performance of our system

An optimisation framework for the strategic design of synthetic natural gas (BioSNG) supply chains

A general optimisation framework based on a spatially-explicit multiperiod mixed integer linear programming (MILP) model is proposed to address the strategic design of BioSNG supply chains. The framework considers procurement of feedstocks, plantation of energy crops, and different modes for transportation of feedstocks and final products. The mathematical framework allows researches and policy makers to investigate scenarios that promote the development of BioSNG supply chains in a regional and/or national context. The capabilities of the proposed model are illustrated through the implementation of a set of case studies based on the UK. The results revealed that domestic resources in the UK can supply up to 21.4% of the total gas demand projected by the UK National Grid in the scenario “Slow progression” for a planning horizon of 20 years. However, despite the considerable potential for production of BioSNG, the role of the government through subsidisation schemes such as feed-in tariff and Renewable Obligation Certificates (ROCs) is crucial in order to make the development of these resources economically attractive for private sectors

Evolution of Bilateral Capital Flows to Developing Countries at Intensive and Extensive Margins

The capital flows network has changed substantially, bringing new investors and target economies into play. Related, a recent intensification of capital flows to low income countries (LICs) has posed a number of questions. Most importantly, the very nature of those flows and important factors affecting foreign investors decision which can ultimately affect growth prospects of low income countries (together with an issue of sustainability) remain open for an academic probe. Due to an existence of a share of costs which is fixed in nature, there is a need to analyze capital flows and their evolution at two margins: intensive and extensive. This paper presents a parsimonious theoretical account that is consequently mapped into an econometric framework where we allow for two-tier decisions and cross-sectional dependence. Results indicate that market entry costs affect investment decisions pertinent to the LICs, consistently with the static theory. However, persistence in extensive margin eliminates this effect once dynamics is allowed for.Heterogeneous Panel

Do individual differences in emotion regulation mediate the relationship between mental toughness and symptoms of depression?

Mental Toughness (MT) provides crucial psychological capacities for achievement in sports, education, and work settings. Previous research examined the role of MT in the domain of mental health and showed that MT is negatively associated with and predictive of fewer depressive symptoms in nonclinical populations. The present study aimed at (1) investigating to what extent mentally tough individuals use two emotion regulation strategies: cognitive reappraisal and expressive suppression; (2) exploring whether individual differences in emotion regulation strategy use mediate the relationship between MT and depressive symptoms. Three hundred sixty-four participants (M = 24.31 years, SD = 9.16) provided self-reports of their levels of MT, depressive symptoms, and their habitual use of cognitive reappraisal and expressive suppression. The results showed a statistically significant correlation between MT and two commonly used measures of depressive symptoms. A small statistically significant positive correlation between MT and the habitual use of cognitive reappraisal was also observed. The correlation between MT and the habitual use of expressive suppression was statistically significant, but the size of the effect was small. A statistical mediation model indicated that individual differences in the habitual use of expressive suppression mediate the relationship between MT and depressive symptoms. No such effect was found for the habitual use of cognitive reappraisal. Implications of these findings and possible avenues for future research are discussed