12,815 research outputs found
Higher Order Approximation to the Hill Problem Dynamics about the Libration Points
An analytical solution to the Hill problem Hamiltonian expanded about the
libration points has been obtained by means of perturbation techniques. In
order to compute the higher orders of the perturbation solution that are needed
to capture all the relevant periodic orbits originated from the libration
points within a reasonable accuracy, the normalization is approached in complex
variables. The validity of the solution extends to energy values considerably
far away from that of the libration points and, therefore, can be used in the
computation of Halo orbits as an alternative to the classical
Lindstedt-Poincar\'e approach. Furthermore, the theory correctly predicts the
existence of the two-lane bridge of periodic orbits linking the families of
planar and vertical Lyapunov orbits.Comment: 28 pages, 8 figure
How secular staganation can affect income class structure in european countries: institutional and policy implications
In recent years, there has been increasing debate about the low economic growth and the risk of secular stagnation in economically advanced countries. Some authors point out possible links between secular stagnation and income inequality, causally in both directions. Taking as a reference point the theoretical literature on the relationship between economic growth and income distribution, this study examines the extent to which different levels of economic growth are associated with the income class structure in European countries between 1993 and 2016, focusing on income distribution before taxes and transfers (market incomes). We highlight that in recession periods the size and income share of the middle class decrease, while the opposite occurs in periods with strong economic growth rates. Nevertheless, when growth rates are modest the patterns are much less clearly defined. Some policy and institutional implications are discussed in order to tackle the concerns of secular stagnation and inequality simultaneously.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Testing the Mechanism for the LSP Stability at the LHC
The lightest supersymmetric particle (LSP) is a natural candidate for the
cold dark matter of the universe. In this Letter we discuss how to test the
mechanism responsible for the LSP stability at the LHC. We note that if
R-parity is conserved dynamically one should expect a Higgs boson which decays
mainly into two right-handed neutrinos (a "leptonic" Higgs) or into two
sfermions. The first case could exhibit spectacular lepton number violating
signals with four secondary vertices due to the long-lived nature of
right-handed neutrinos. These signals, together with the standard channels for
the discovery of SUSY, could help to establish the underlying theory at the TeV
scale.Comment: 4 pages, 3 figures, 1 table, minor corrections, published in Physics
Letters
Espectro de diseño y zonificación sísmica basada en periodos fundamentales de vibración de los suelos, en el área urbana de la ciudad de Mateare
La sismología es el estudio científico de las vibraciones mecánicas de la tierra. Dicho estudio se lleva a cabo mediante el análisis de datos contenidos en sismogramas, los cuales son grabaciones de vibraciones resultado de eventos naturales, como son: terremotos, erupciones volcánicas o explosiones hechas por el hombre. Tales fenómenos han atraído fuertemente la atención de la humanidad por siglos y aún en nuestro tiempo provocan sentimientos de miedo y misterio además de gran curiosidad intelectual. La modificación que sufre la señal sísmica en diferentes sitios es causada por las alteraciones que sufren las ondas debido a las condiciones geológicas, topográficas y de rigidez del subsuelo. La importancia de conocer estas alteraciones conocidas como “efectos locales”, conduce a la necesidad de realizar estudios de microzonificación en áreas urbanas para detectar aquellas zonas que exhiban problemas especiales. En esta investigación se realizara el estudio de algunas propiedades dinámicas de los suelos para la ciudad de Mateare con fines de microzonificación sísmica. Específicamente las propiedades dinámicas a determinar serán periodos fundamentales de vibración y velocidades de ondas S. Esto nos servirá para proponer microzonas en la ciudad así como para determinar el espectro de respuesta y compararlo con el espectro de diseño sugerido en el RNC-07. Esto es sumamente importante a la hora de realizar los diseños de edificaciones pues aporta herramientas a los diseñadores para realizar mejores análisis de acuerdo a las propiedades dinámicas de los suelos de la ciudad. Para obtener los periodos fundamentales de vibración del suelo se realizaran 50 mediciones de Microtremores en diferentes puntos del área de estudio. Posteriormente se realizara el análisis de datos obtenidos de las mediciones de Microtremores realizados con un sismógrafo, el análisis será determinado por el programa Geops
The Markyt visualisation, prediction and benchmark platform for chemical and gene entity recognition at BioCreative/CHEMDNER challenge
Biomedical text mining methods and technologies have improved significantly in the last decade. Considerable efforts have been invested in understanding the main challenges of biomedical literature retrieval and extraction and proposing solutions to problems of practical interest. Most notably, community-oriented initiatives such as the BioCreative challenge have enabled controlled environments for the comparison of automatic systems while pursuing practical biomedical tasks. Under this scenario, the present work describes the Markyt Web-based document curation platform, which has been implemented to support the visualisation, prediction and benchmark of chemical and gene mention annotations at BioCreative/CHEMDNER challenge. Creating this platform is an important step for the systematic and public evaluation of automatic prediction systems and the reusability of the knowledge compiled for the challenge. Markyt was not only critical to support the manual annotation and annotation revision process but also facilitated the comparative visualisation of automated results against the manually generated Gold Standard annotations and comparative assessment of generated results. We expect that future biomedical text mining challenges and the text mining community may benefit from the Markyt platform to better explore and interpret annotations and improve automatic system predictions. Database URL: http://www.markyt.org, https://github.com/sing-group/MarkytThis work was partially funded by the [14VI05] Contract-Programme from the University of Vigo and the Agrupamento INBIOMED from DXPCTSUG-FEDER unha maneira de facer Europa (2012/273) as well as by the Foundation for Applied Medical Research, University of Navarra (Pamplona, Spain). The research leading to these results has received funding from the European Union's Seventh Framework Programme FP7/REGPOT-2012-2013.1 under grant agreement no 316265, BIOCAPS
Benchmarking biomedical text mining web servers at BioCreative V.5: the technical Interoperability and Performance of annotation Servers - TIPS track
The TIPS track consisted in a novel experimental task under the umbrella
of the BioCreative text mining challenges with the aim to, for the first time
ever, carry out a text mining challenge with particular focus on the continuous
assessment of technical aspects of text annotation web servers, specifically of
biomedical online named entity recognition systems.
A total of 13 teams registered annotation servers, implemented in various programming
languages, supporting up to 12 different general annotation types. The
continuous evaluation period took place from February to March 2017. The systematic
and continuous evaluation of server responses accounted for testing periods
of low activity and moderate to high activity. Moreover three document
provider settings were covered, including also NCBI PubMed. For a total of
4,092,502 requests, the median response time for most servers was below 3.74 s
with a median of 10 annotations/document. Most of the servers showed great
reliability and stability, being able to process 100,000 requests in 5 days.info:eu-repo/semantics/publishedVersio
Valoración de los scores Apache II y Ranson como predictores de severidad en pancreatitis aguda al ingreso en el Hospital Nacional Dos de Mayo, agosto 2011 a julio del 2012
Publicación a texto completo no autorizada por el autorEl documento digital no refiere asesorValora los scores de Ranson y APACHE II, como predictivos de severidad en pacientes con diagnóstico de ingreso al Servicio de Medicina de pancreatitis aguda en el Hospital de Nacional Dos de Mayo. Agosto 2011 a julio de 2012. Se realizó un estudio observacional, descriptivo, retrospectivo y transversal. Se revisaron 81 historias de pacientes con diagnóstico de pancreatitis aguda a quienes se les aplicó los Scores Ranson y APACHE II como scores predictores de severidad en el servicio de Medicina del Hospital de Nacional Dos de Mayo en el periodo que comprendió el estudio. Para el análisis descriptivo de variables cuantitativas se empleó medidas de tendencia central y de dispersión, para el análisis cualitativo se utilizó frecuencias absolutas y relativas. La valoración de los indicadores predictivos se realizó a través de la sensibilidad, especificidad, Valor Predictivo Positivo (VPP) y Valor Predictivo Negativo (VPN). El 55.6% de pacientes con pancreatitis aguda fueron varones y el 44.4%, mujeres. La edad promedio fue 50,5 años donde el rango de edad estuvo comprendido entre 24 años a 76 años. La etiología de la pancreatitis aguda más frecuente fue de tipo biliar (65.4 %). El score APACHE II permitió clasificar a los pacientes como grado severo de pancreatitis aguda al 18.5 % de ellos mientras que el score Ranson clasificó como grado severo al 14.8 % de los pacientes con pancreatitis aguda. Los Scores de Ranson y APACHE II permitieron identificar una predominancia de casos leves de pancreatitis aguda. Los resultados de TAC evidenciaron que el 48,1% tuvieron resultado normal, en los pacientes con hallazgos anormales se encontró edema de páncreas en el 7,4% y necrosis (mayor al 50%) en el 7,4%. La evaluación de los valores predictivos del score Ranson fue: Sensibilidad 57.1%, Especificidad 100%, Valor Predictivo Negativo (VPN) 86.9% y Valor Predictivo Positivo de 100%. La Sensibilidad de APACHE II fue 71.4%, Especificidad 100%, VPN 90.9% y VPP de 100%. Se observó que los scores APACHE II y Ranson poseen un buen valor predictivo positivo como negativo, lo que permite descartar severidad dentro de las 24 horas de ingreso de los pacientes con pancreatitis aguda evaluados. Los scores APACHE II y Ranson tienen la capacidad de predecir severidad de la pancreatitis aguda en todos los pacientes que son evaluados dentro de las 24 horas al ingreso, no se observó diferencias en el valor predictivo entre ambas pruebas.Trabajo académic
Optimal Risk Management Before, During and After the 2008-09 Financial Crisis
In this paper we advance the idea that optimal risk management under the Basel II Accord will typically require the use of a combination of different models of risk. This idea is illustrated by analyzing the best empirical models of risk for five stock indexes before, during,and after the 2008-09 financial crisis. The data used are the Dow Jones Industrial Average, Financial Times Stock Exchange 100, Nikkei, Hang Seng and Standard and Poor’s 500 Composite Index. The primary goal of the exercise is to identify the best models for risk management in each period according to the minimization of average daily capital requirements under the Basel II Accord. It is found that the best risk models can and do vary before, during and after the 2008-09 financial crisis. Moreover, it is found that an aggressive risk management strategy, namely the supremum strategy that combines different models of risk, can result in significant gains in average daily capital requirements, relative to the strategy of using single models, while staying within the limits of the Basel II Accord.Financial portfolios, daily capital charges, frequency of violations, magnitude of violations, optimizing strategy, risk forecasts, value-at-risk, green zone, red zone.
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