Distribution functions for a family of axially symmetric galaxy models

We present the derivation of distribution functions for the first four members of a family of disks, previously obtained in (MNRAS, 371, 1873, 2006), which represent a family of axially symmetric galaxy models with finite radius and well behaved surface mass density. In order to do this we employ several approaches that have been developed starting from the potential-density pair and, essentially using the method introduced by Kalnajs (Ap. J., 205, 751, 1976) we obtain some distribution functions that depend on the Jacobi integral. Now, as this method demands that the mass density can be properly expressed as a function of the gravitational potential, we can do this only for the first four discs of the family. We also find another kind of distribution functions by starting with the even part of the previous distribution functions and using the maximum entropy principle in order to find the odd part and so a new distribution function, as it was pointed out by Dejonghe (Phys. Rep., 133, 217, 1986). The result is a wide variety of equilibrium states corresponding to several self-consistent finite flat galaxy models.Comment: 12 pages, 7 figures, updated version, accepted for publication in Rev. Acad. Colomb. Cienc. Ex. Fis. Na

Geometric Aspects of Holographic Bit Threads

We revisit the recent reformulation of the holographic prescription to compute entanglement entropy in terms of a convex optimization problem, introduced by Freedman and Headrick. According to it, the holographic entanglement entropy associated to a boundary region is given by the maximum flux of a bounded, divergenceless vector field, through the corresponding region. Our work leads to two main results: (i) We present a general algorithm that allows the construction of explicit thread configurations in cases where the minimal surface is known. We illustrate the method with simple examples: spheres and strips in vacuum AdS, and strips in a black brane geometry. Studying more generic bulk metrics, we uncover a sufficient set of conditions on the geometry and matter fields that must hold to be able to use our prescription. (ii) Based on the nesting property of holographic entanglement entropy, we develop a method to construct bit threads that maximize the flux through a given bulk region. As a byproduct, we are able to construct more general thread configurations by combining (i) and (ii) in multiple patches. We apply our methods to study bit threads which simultaneously compute the entanglement entropy and the entanglement of purification of mixed states and comment on their interpretation in terms of entanglement distillation. We also consider the case of disjoint regions for which we can explicitly construct the so-called multi-commodity flows and show that the monogamy property of mutual information can be easily illustrated from our constructions.Comment: 48 pages, multiple figures. v3: matches published versio

Dirac materials in parallel non-uniform electromagnetic fields generated by SUSY: A new class of chiral Planar Hall Effect?

Within a Supersymmetric Quantum Mechanics (SUSY-QM) framework, the (3+1) Dirac equation describing a Dirac material in the presence of external parallel electric and magnetic fields is solved. Considering static but non-uniform electric and magnetic profiles with translational symmetry along the y-direction, the Dirac equation is transformed into two decoupled pairs of Schr\"odinger equations, one for each chirality of the fermion fields. Taking trigonometric and hyperbolic profiles for the vector and scalar potentials, respectively, we arrive at SUSY partner P\"oschl-Teller-like quantum potentials. Restricting to the conditions of the potentials that support an analytic zero-mode solution, we obtain a nontrivial current density in the same plane where the electric and magnetic fields lie, but perpendicular to both of them, indicating the possibility of realizing the Planar Hall Effect. Furthermore, this non-vanishing current density is the sum of current densities for the left- and right-chiralities, suggesting that the net current is a consequence of chiral symmetry.Comment: 10 pages, 6 figure

Classification Rule Mining with Iterated Greedy

In the context of data mining, classi cation rule discovering is the task of designing accurate rule based systems that model the useful knowledge that di erentiate some data classes from others, and is present in large data sets. Iterated greedy search is a powerful metaheuristic, successfully applied to di erent optimisation problems, which to our knowledge, has not previously been used for classi cation rule mining. In this work, we analyse the convenience of using iterated greedy algorithms for the design of rule classi cation systems. We present and study di erent alternatives and compare the results with state-of-the-art methodologies from the literature. The results show that iterated greedy search may generate accurate rule classi cation systems with acceptable interpretability level

Loss Functions and Metrics in Deep Learning

One of the essential components of deep learning is the choice of the loss function and performance metrics used to train and evaluate models. This paper reviews the most prevalent loss functions and performance measurements in deep learning. We examine the benefits and limits of each technique and illustrate their application to various deep-learning problems. Our review aims to give a comprehensive picture of the different loss functions and performance indicators used in the most common deep learning tasks and help practitioners choose the best method for their specific task.Comment: 53 pages, 5 figures, 7 tables, 86 equation

Energy, added sugar, and saturated fat contributions of taxed beverages and foods in Mexico

Objective. To estimate the dietary contribution of taxed beverages and foods. Materials and methods. Using 24-hour diet recall data from the Ensanut 2012 (n=10 096), we estimated the contribution of the items which were taxed in 2014 to the total energy, added sugar, and saturated fat intakes in the entire sample and by sociodemographic characteristics. Results. The contributions for energy, added sugar, and saturated fat were found to be 5.5, 38.1, and 0.4%, respectively, for the taxed beverages, and 14.4, 23.8, and 21.4%, respectively, for the taxed foods. Children and adolescents (vs. adults), medium and high socioeconomic status (vs. low), urban area (vs. rural), and North and Center region (vs. South) had higher energy contribution of taxed beverages and foods. The energy contribution was similar between males and females. Conclusions. These taxes covered an important proportion of Mexicans’ diet and therefore have the potential to improve it meaningfully

Historical reconstruction of the population dynamics of southern right whales in the southwestern Atlantic Ocean

Understanding the recovery of whale populations is critical for developing population-management and conservation strategies. The southern right whale (SRW) Eubalena australis was one of the baleen whale species that has experienced centuries of exploitation. We assess here for the first time the population dynamics of the SRW from the southwestern Atlantic Ocean at the regional level to measure numerically the effect of whaling and estimate the population trend and recovery level after depletion. We reconstructed the catch history of whaling for the period 1670–1973 by an extensive review of different literature sources and developed a Bayesian state-space model to estimate the demographic parameters. The population trajectory indicated that the pre-exploitation abundance was close to 58,000 individuals (median = 58,212; 95% CI = 33,329–100,920). The abundance dropped to its lowest abundance levels in the 1830s when fewer than 2,000 individuals remained. The current median population abundance was estimated at 4,742 whales (95% CI = 3,853–6,013), suggesting that the SRW population remains small relative to its pre-exploitation abundance (median depletion P2021 8.7%). We estimated that close to 36% of the SRW population visits the waters of the Península Valdés, the main breeding ground, every year. Our results provide insights into the severity of the whaling operation in the southwestern Atlantic along with the population´s response at low densities, thus contributing to understand the observed differences in population trends over the distributional range of the species worldwide.Fil: Romero, Maria Alejandra. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; ArgentinaFil: Coscarella, Mariano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Adams, G. A.. University of Washington; Estados UnidosFil: Pedraza, Juan C.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: González, Raul Alberto Candido. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; ArgentinaFil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentin

Hysteroscopic findings and intrauterine pathology treatment in Mexican infertile women

Background: Hysteroscopy is a minimally invasive approach in gynecologic surgery and one of the main procedures performed on women undergoing fertility treatments. Intrauterine pathology negatively affects fertility by decreasing endometrial receptivity and embryo implantation success, and its prevalence has been reported between 19% and 62%. The aim of our study was to describe the hysteroscopic findings, prevalence of intrauterine pathology, the instruments used for the treatment of structural lesions in Mexican infertile women; and to compare the relationship of positive findings with the type of infertility. Methods: This was a descriptive, cross-sectional study conducted at fertility clinic at a private hospital. Results: We evaluated 191 hysteroscopies; the mean age of women was 35.5+3.2 years and the mean time of infertility 5.7+3.2 years. Primary infertility was the most prevalent (79.1%). In 118 cases (61.8%), uterine cavity abnormalities were diagnosed, the most frequent findings were: polyps (n=51, 26.7%), endometritis (n=30, 15.7%), fibroids (n=15, 7.6 %), synechiae (n=12, 6.5%), and müllerian anomalies (n=10, 5.3%). For structural pathology treatment, cold scissors and bipolar energy were used in 65.5% and 34.5%, respectively. Conclusions: Overall intrauterine pathology prevalence in our study population was 61.8%. Cold scissors and bipolar energy were used for structural lesions treatment. When comparing the relationship of hysteroscopic findings, no statistically significant difference was found in the presence of positive findings, with the type of infertility.