Magnetoresistance of YBa2Cu3O7 in the "cold spots" model

We calculate the in-plane magnetoresistance $\Delta\rho_{xx}/\rho_{xx}$ of YBa$_2$Cu$_3$O$_7$ in a magnetic field applied perpendicular to the $CuO_2$ planes for the ``cold spots'' model. In this model, the electron relaxation time $\tau_2\propto1/T^2$ at small regions on the Fermi surface near the Brillouin zone diagonals is much longer than the relaxation time $\tau_1\propto1/T$ at the rest of the Fermi surface ($T$ is temperature). In qualitative agreement with the experiment, we find that Kohler's rule is strongly violated, but the ratio $\Delta\rho_{xx}/\rho_{xx}\tan^2\theta_H$, where $\tan\theta_H$ is the Hall angle, is approximately temperature-independent. We find the ratio is about 5.5, which is of the same order of magnitude as in the experiment.Comment: RevTeX, 4 pages, 6 figures. V.2: 2 references adde

Statistical nature of non-Gaussianity from cubic order primordial perturbations: CMB map simulations and genus statistic

We simulate CMB maps including non-Gaussianity arising from cubic order perturbations of the primordial gravitational potential, characterized by the non-linearity parameter $g_{NL}$. The maps are used to study the characteristic nature of the resulting non-Gaussian temperature fluctuations. We measure the genus and investigate how it deviates from Gaussian shape as a function of $g_{NL}$ and smoothing scale. We find that the deviation of the non-Gaussian genus curve from the Gaussian one has an antisymmetric, sine function like shape, implying more hot and more cold spots for $g_{NL}>0$ and less of both for $g_{NL}<0$. The deviation increases linearly with $g_{NL}$ and also exhibits mild increase as the smoothing scale increases. We further study other statistics derived from the genus, namely, the number of hot spots, the number of cold spots, combined number of hot and cold spots and the slope of the genus curve at mean temperature fluctuation. We find that these observables carry signatures of $g_{NL}$ that are clearly distinct from the quadratic order perturbations, encoded in the parameter $f_{NL}$. Hence they can be very useful tools for distinguishing not only between non-Gaussian temperature fluctuations and Gaussian ones but also between $g_{NL}$ and $f_{NL}$ type non-Gaussianities.Comment: 18+1 page

Identification and location of hot and cold spots of treated prevalence of depression in Catalonia (Spain)

Abstract Background Spatial analysis is a relevant set of tools for studying the geographical distribution of diseases, although its methods and techniques for analysis may yield very different results. A new hybrid approach has been applied to the spatial analysis of treated prevalence of depression in Catalonia (Spain) according to the following descriptive hypotheses: 1) spatial clusters of treated prevalence of depression (hot and cold spots) exist and, 2) these clusters are related to the administrative divisions of mental health care (catchment areas) in this region. Methods In this ecological study, morbidity data per municipality have been extracted from the regional outpatient mental health database (CMBD-SMA) for the year 2009. The second level of analysis mapped small mental health catchment areas or groups of municipalities covered by a single mental health community centre. Spatial analysis has been performed using a Multi-Objective Evolutionary Algorithm (MOEA) which identified geographical clusters (hot spots and cold spots) of depression through the optimization of its treated prevalence. Catchment areas, where hot and cold spots are located, have been described by four domains: urbanicity, availability, accessibility and adequacy of provision of mental health care. Results MOEA has identified 6 hot spots and 4 cold spots of depression in Catalonia. Our results show a clear spatial pattern where one cold spot contributed to define the exact location, shape and borders of three hot spots. Analysing the corresponding domain values for the identified hot and cold spots no common pattern has been detected. Conclusions MOEA has effectively identified hot/cold spots of depression in Catalonia. However these hot/cold spots comprised municipalities from different catchment areas and we could not relate them to the administrative distribution of mental care in the region. By combining the analysis of hot/cold spots, a better statistical and operational-based visual representation of the geographical distribution is obtained. This technology may be incorporated into Decision Support Systems to enhance local evidence-informed policy in health system research.</p

Understanding the careers cold spots.

This paper sets out our cold spots analysis which provides us with some important insights about how opportunities are organised in England. In the report we examine which areas have: high levels of engagement between schools and employers; young people who are making opportunity informed decisions and achieving positive outcomes in terms of education and employment. We also examine the areas in which young people are most likely to experience substantial barriers. This analysis allows The Careers & Enterprise Company to understand where more career support is needed and to direct our resources towards these areas. We hope that it this analysis will also guide the activities of others working in this space.N/