5,987 research outputs found
Higgs and new physics at high energy
The observation of a new particle in the search for the Standard Model (SM)
Higgs boson at the LHC, reported by the ATLAS and CMS collaborations, is a
milestone in the quest to understand electroweak symmetry breaking. The
evidence at the level of 5 for a Higgs boson-like particle has been
published by both experiments after a preliminary analysis of the data from the
LHC Run-I. Precision measurements of the new particle are of critical
importance. This document reviews the mass and spin measurement, the couplings
scale factor measurements and the limits on new physics derived from these
results.Comment: Presented at the 2014 Flavor Physics and CP Violation (FPCP-2014),
Marseille, France, May 26-30 2014, 9 pages, 9 figure
Evolutionary game theory: Temporal and spatial effects beyond replicator dynamics
Evolutionary game dynamics is one of the most fruitful frameworks for
studying evolution in different disciplines, from Biology to Economics. Within
this context, the approach of choice for many researchers is the so-called
replicator equation, that describes mathematically the idea that those
individuals performing better have more offspring and thus their frequency in
the population grows. While very many interesting results have been obtained
with this equation in the three decades elapsed since it was first proposed, it
is important to realize the limits of its applicability. One particularly
relevant issue in this respect is that of non-mean-field effects, that may
arise from temporal fluctuations or from spatial correlations, both neglected
in the replicator equation. This review discusses these temporal and spatial
effects focusing on the non-trivial modifications they induce when compared to
the outcome of replicator dynamics. Alongside this question, the hypothesis of
linearity and its relation to the choice of the rule for strategy update is
also analyzed. The discussion is presented in terms of the emergence of
cooperation, as one of the current key problems in Biology and in other
disciplines.Comment: Review, 48 pages, 26 figure
Time Scales in Evolutionary Dynamics
Evolutionary game theory has traditionally assumed that all individuals in a
population interact with each other between reproduction events. We show that
eliminating this restriction by explicitly considering the time scales of
interaction and selection leads to dramatic changes in the outcome of
evolution. Examples include the selection of the inefficient strategy in the
Harmony and Stag-Hunt games, and the disappearance of the coexistence state in
the Snowdrift game. Our results hold for any population size and in the
presence of a background of fitness.Comment: Final version with minor changes, accepted for publication in
Physical Review Letter
GAMES: A new Scenario for Software and Knowledge Reuse
Games are a well-known test bed for testing search algorithms and learning methods, and many authors have presented numerous reasons for the research in this area. Nevertheless, they have not received the attention they deserve as software projects.
In this paper, we analyze the applicability of software
and knowledge reuse in the games domain. In spite of the
need to find a good evaluation function, search algorithms
and interface design can be said to be the primary concerns.
In addition, we will discuss the current state of the main
statistical learning methods and how they can be addressed
from a software engineering point of view. So, this paper
proposes a reliable environment and adequate tools, necessary in order to achieve high levels of reuse in the games domain
Diavideos: a Diabetes Health Video Portal
Diavideos1 is a web platform that collects trustworthy
diabetes health videos from YouTube and offers them in a easy
way. YouTube is a big repository of health videos, but good
content is sometimes mixed with misleading and harmful
videos such as promoting anorexia [1].Diavideos is a web
portal that provides easy access to a repository of trustworthy
diabetes videos. This poster describes Diavideos and explains
the crawling method used to retrieve these videos from trusted
channels
Universal temporal features of rankings in competitive sports and games
Many complex phenomena, from the selection of traits in biological systems to
hierarchy formation in social and economic entities, show signs of competition
and heterogeneous performance in the temporal evolution of their components,
which may eventually lead to stratified structures such as the wealth
distribution worldwide. However, it is still unclear whether the road to
hierarchical complexity is determined by the particularities of each phenomena,
or if there are universal mechanisms of stratification common to many systems.
Human sports and games, with their (varied but simplified) rules of competition
and measures of performance, serve as an ideal test bed to look for universal
features of hierarchy formation. With this goal in mind, we analyse here the
behaviour of players and team rankings over time for several sports and games.
Even though, for a given time, the distribution of performance ranks varies
across activities, we find statistical regularities in the dynamics of ranks.
Specifically the rank diversity, a measure of the number of elements occupying
a given rank over a length of time, has the same functional form in sports and
games as in languages, another system where competition is determined by the
use or disuse of grammatical structures. Our results support the notion that
hierarchical phenomena may be driven by the same underlying mechanisms of rank
formation, regardless of the nature of their components. Moreover, such
regularities can in principle be used to predict lifetimes of rank occupancy,
thus increasing our ability to forecast stratification in the presence of
competition
Estructura comunitaria de la ictiofauna bentónica del delta del Orinoco y Golfo de Paria (Venezuela), 50 años después de la construcción del dique del caño Manamo
To evaluate the impacts of water flow restriction and regulation caused by the construction of a dike across Manamo Channel, variations in the benthic fish communities were studied in the mouths of three streams or channels (Pedernales, Angostura and Manamo) of the Orinoco River Delta and one stream (Venado) that flows directly into the Gulf of Paria, during one (annual) hydrological cycle. Fishes were sampled with a shrimp trawl net. Of the 78 species collected, five were resident, 12 temporary and 62 occasional. Juvenile phases of all species were collected. Species with greater IVI values were Cathorops sp., Achirus achirus, Stellifer naso and Colomesus psittacus. No significant differences were obtained for the physical and chemical habitat parameters measured: depth, salinity and transparency, nor in the water levels of the streams even in different hydro-phases of the year. Salinity never dropped to zero and no changes in fish species composition were detected. These results lead us to hypothesize that the impacts of the dike constructed in Manamo Channel also extend to other streams of the Orinoco River Delta and even the one studied (Venado) that empties into the Gulf of Paria, where estuarine conditions prevailed during the entire study period of one year, with no observed changed in the hydrological regimen.Con el objetivo de evaluar el efecto de la regulación de las aguas del caño Manamo (por la construcción de un dique), sobre la ictiofauna bentónica de algunos caños del delta del río Orinoco y Golfo de Paria, se estudió la variación de la estructura comunitaria de peces bentónicos en la desembocadura de tres caños del delta del río Orinoco (Pedernales, Angostura y Manamo) y un caño del golfo de Paria (Venado) durante un ciclo hidrológico anual. De las 78 especies colectadas, cinco fueron residentes, 12 temporales y 61 ocasionales; todas registraron ejemplares en estado juvenil. Las especies con mayores valores de IVI fueron Cathorops sp., Achirus achirus, Stellifer naso y Colomesus psittacus. No se observaron diferencias significativas entre los parámetros físico-químicos analizados (profundidad, salinidad y transparencia), ni a nivel de caños, ni entre hidrofases. La salinidad nunca registró valores menores de 4 % y no se observaron cambios en la composición de especies de la comunidad. Con los resultados obtenidos se plantea la hipótesis de que la construcción del dique sobre el caño Manamo en los años 60, afectó el comportamiento natural de este sistema y de otros caños del delta e incluso del golfo de Paria (caño Venado), registrando en las desembocaduras de todos los caños características de un estuario continuo (sin cambios en el régimen hidrológico y salinidad) durante todo el año
Calidad técnica del instrumento de evaluación de los proyectos de investigación y tesis de la maestría
16 p.El trabajo de grado de maestría en Psicología de la Universidad Católica de Colombia es un requisito central en el proceso de formación del estudiante, dado que se trata de un programa con énfasis investigativo, cuya pretensión, además de fortalecer habilidades en lo disciplinar, atiende a las orientaciones del Decreto 1295 de 2010. En este sentido, el Centro de Estudios e Investigaciones en Psicología (CEIPS) de la Facultad de Psicología de la Universidad Católica de Colombia ha realizado jornadas de comité de investigaciones desde el año 2010 orientadas a la generación de un instrumento estandarizado que permita obtener una evaluación objetiva de los evaluadores de los proyectos. A lo largo de estos años se han generado tres versiones del formato de evaluación: la primera incluía criterios de calidad y solicitaba una evaluación cualitativa de la percepción del par evaluador; la segunda, elaborada en 2013, contenía los mismos aspectos que la anterior, pero en ella había la posibilidad de emitir un concepto en el que el jurado decidía si el proyecto quedaba pendiente de aprobación hasta que se verificara la completitud de las sugerencias o modificaciones; y, finalmente, la versión actual, vigente desde el año 2015, busca implementar un sistema de calificación de los criterios asociados a los proyectos de grado, utilizando una escala numérica con referencia en el formato de informe técnico de avance de proyectos implementado por Conciencias.Introducción
Materiales y método
Resultados
Calidad técnica del instrumento
Discusión
Conclusiones
Referencia
Synthesis of geopolymers from alkaline activation of gold mining wastes
Resumen
Este trabajo presenta los resultados preliminares relacionados con el desarrollo de polímeros inorgánicos
(geopolímeros) a partir de la activación alcalina de residuos de la minería de oro. La caracterización mineralógica
y fisicoquímica de estos residuos de minería de oro muestra su gran potencial como fuente de precursores
geopoliméricos como una alternativa razonable para el desarrollo de aglutinantes activados alcalinamente amigables
con el medio ambiente. El proceso de geopolimerización es un camino viable para transformar estos residuos en
materiales con alta resistencia mecánica, alta inercia química y alta durabilidad en el tiempo, dando valor agregado
a los subproductos de la actividad minera. Abstract
This paper reports preliminary results related to the development of inorganic polymers (geopolymers) from alkaliactivation
of gold mining wastes. Mineralogical and physicochemical characterization of these gold mining wastes
shows their significant potential as geopolymeric source precursors as a reasonable alternative to the development
of alkali-activated friendly environmental binders. Geopolymerization process is a viable way to transform these
residues in materials with high mechanical strength, high chemical inertness and high durability over time, giving
add value to the by-products of the mining industry
Reflectionless discrete perfectly matched layers for higher-order finite difference schemes
This paper introduces discrete-holomorphic Perfectly Matched Layers (PMLs)
specifically designed for high-order finite difference (FD) discretizations of
the scalar wave equation. In contrast to standard PDE-based PMLs, the proposed
method achieves the remarkable outcome of completely eliminating numerical
reflections at the PML interface, in practice achieving errors at the level of
machine precision. Our approach builds upon the ideas put forth in a recent
publication [Journal of Computational Physics 381 (2019): 91-109] expanding the
scope from the standard second-order FD method to arbitrary high-order schemes.
This generalization uses additional localized PML variables to accommodate the
larger stencils employed. We establish that the numerical solutions generated
by our proposed schemes exhibit an exponential decay rate as they propagate
within the PML domain. To showcase the effectiveness of our method, we present
a variety of numerical examples, including waveguide problems. These examples
highlight the importance of employing high-order schemes to effectively address
and minimize undesired numerical dispersion errors, emphasizing the practical
advantages and applicability of our approach
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