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

Action-Research, Professional Development of the Physical Education Teachers in Rural Schools

La finalidad de este estudio es analizar la influencia de un grupo de trabajo de Investigación-Acción en el desarrollo profesional de maestros de Educación Física (EF) que ejercen su labor docente en la Escuela Rural. El diseño es un estudio multicaso. Para la recogida de datos se utilizaron: historias de vida, entrevistas en profundidad, análisis de documentos y diario de investigación. El análisis de datos se realizó a través de un proceso de categorización. Los resultados muestran que: (a)-los maestros de EF que ejercen su labor docente en la escuela rural pasan por situaciones difíciles y complicadas los primeros años, y que la pertenencia a grupos de Investigación-Acción les ayuda a que la adaptación a este contexto educativo sea más rápida y fácil; (b)-la metodología de Investigación-Acción genera procesos de reflexión que ayudan a mejorar su práctica docente, influye positivamente en su desarrollo profesional y supone un apoyo.The purpose of this paper is to analyze the influence of a Action Research group on professional development of physical education (PE) teachers in rural school. The research methodology used was case study. Data collection was conducted through interviews, life stories, document analysis and research notebook. Data analysis was performed through a categorization process. The results show that: (a)-PEF teachers in rural school engaged in difficult situations at early years, and to be a membership of Action Research group helps them adapt to this context educational faster and easier, (b)-the Action Research methodology generates reflective processes that help improve their teaching, has a positive influence on their professional development and represent a suppor

Children’s narratives on migrant refugees: a practice of global citizenship

Globalisation has brought about great social and economic impact, as well as great challenges. Major developments have taken place in the mobility of capital and, to a lesser extent, of goods; not so in the mobility of people seeking asylum due to persecution and war. This article approaches the phenomenon of migration, particularly of refugees, as learning content for early childhood. The research is presented from a qualitative approach based on the results of a project on this topic implemented in a rural school in Spain. The results of the data analysis reveal that children attribute external reasons, of survival, to the refugees’ forced departure from their country of origin. The children’s imaginary reproduces the social construction of adults on the status and situation of refugees, and they also show a critical attitude towards the violation of human rights and the abuse of fellow children. Finally, respect, cultural empathy and social commitment in the face of injustice are presented as fundamental values for education in global citizenship from the earliest stages of schooling

Sensitivity analysis in a camera-LiDAR calibration model

Recientemente, la fusión de datos entre una cámara y un sensor de profundidad del tipo LiDAR se ha convertido en un problema de gran interés en la industria y en la ingeniería. La calidad de los modelos 3D producidos depende, en buena manera, de un proceso correcto de calibración entre ambos sensores. En este artículo, se realiza un análisis de sensibilidad en un modelo de calibración cámara-LiDAR. Se ha calculado individualmente la variabilidad de cada parámetro por el método de Sobol, basado en la técnica de ANOVA, y el método FAST, que se basa en el análisis de Fourier. Se han definido los parámetros más sensibles y con mayor tendencia a introducir errores en nuestra plataforma de reconstrucción. Se han simulado múltiples conjuntos de parámetros para su análisis y comparación utilizando los métodos de Monte Carlo e Hipercubo Latino. Se muestran estadísticas sobre la sensibilidad total y global de cada parámetro. Además, se presentan resultados sobre la relación de sensibilidad en la calibración cámara-LiDAR, el costo computacional, el tiempo de simulación, la discrepancia y la homogeneidad en los datos simulados.Recently the data fusion between a camera and a depth sensor of LiDAR type, has become an issue of major concern in industry and engineering. The quality of the delivered 3D models depends greatly on a proper calibration between sensors. This paper presents a sensitivity analysis in a camera-lidar calibration model. The variability of each parameter was calculated individually by the Sobol method, based on ANOVA technique, and the FAST method, which is based on Fourier analysis. Multiple sets of parameters were simulated using Monte Carlo and Latin Hypercube methods for the purpose of comparing the results of the sensitivity analysis. We defined which parameters are the most sensitive and prone to introduce error into our reconstruction platform. Statistics for the total and global sensibility analysis for each sensor and for each parameter are presented. Furthermore, results on the sensitivity ratio on camera-LiDAR calibration, computational cost, time simulation, discrepancy and homogeneity in the simulated data are presented.Peer Reviewe

Validation of Ovine Excreta Using in vitro Gas to Assess Feed for Ruminants

Ovine excreta as inoculum for biogasification was used to assess in vitro and in sacco nutritive value of tropical pastures for ruminants. Pastures under study were: Paspalum notatum, Cynodon nlemfuensis, Panicum maximum, Sporobolus indicus, and Desmodium sp. Excreta were collected on grassy pastures areas. CO2  systematic injections prevented strict anaerobic microorganisms contact with oxygen. A positive and significant correlation resulted from biogasification using either ovine excreta or ovine ruminal fluid. Determinant coefficient was 0,79. Panicum maxi- mum and Cynodon nlemfuensis reached the highest nutritive value, while Sporobolus indicus showed the lowest one. Key Words: ovine excreta, digestibility, nutritive valu

Finite thin disc models of four galaxies in the Ursa Major cluster: NGC3877, NGC3917, NGC3949 and NGC4010

Finite thin disc models of four galaxies in the Ursa Major cluster are presented. The models are obtained by means of the Hunter method and the particular solutions are choosen in such a way that the circular velocities are adjusted very accurately to the observed rotation curves of some specific spiral galaxies. We present particular models for the four galaxies NGC3877, NGC3917, NGC3949 and NGC4010 with data taken from the recent paper by Verheijen & Sancici (2001). By integrating the corresponding surface mass densities, we obtain the total mass M of these four galaxies, all of them being of the order of 10^10 solar masses. These obtained values for M may be taken as a quite accurately estimative of the mass upper bound of these galaxies, since in the model was considered that all their mass was concentrated at the galactic disc. The models can be consider as a first approximation to the obtaining of quite realistic models of spiral galaxiesComment: Submitted to MNRA

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

MIS Transistor with Integrated Waveguide for Electrophotonics and the Effect of Channel Length in Light Detection

In this work, we study the optical response of MOS-like transistors with a Si3N4 integrated waveguide which serves also as the dielectric of the gate, and P-type substrate with 1´1012 cm-3 acceptor concentration and different channel length. Simulation results show the possibility to integrate this kind of MIS transistor as detectors in an electrophotonic circuit compatible with CMOS fabrication process and obtaining electrical gain for low power light signals (below 400 nW)

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.

Silicon-Rich Oxide Obtained by Low-Pressure Chemical Vapor Deposition to Develop Silicon Light Sources

Off stoichiometric silicon oxide, also known as silicon-rich oxide (SRO), is a light-emitting material that is compatible with silicon technology; therefore, it is a good candidate to be used as a light source in all-silicon optoelectronic circuits. The SRO obtained by low-pressure chemical vapor deposition (LPCVD) has shown the best luminescent properties compared to other techniques. In spite of LPCVD being a simple technique, it is not a simple task to obtain SRO with exact silicon excess in a reliable and repetitive way. In this work, the expertise obtained in our group to obtain SRO by LPCVD with precise variation is presented. Also, the characteristics of this SRO obtained in our group are revised and discussed. It is demonstrated that LPCVD is an excellent technique to obtain single layers and multilayers of nanometric single layers with good characteristics