93 research outputs found
Asymmetry in the reconstructed deceleration parameter
We study the orientation dependence of the reconstructed deceleration
parameter as a function of redshift. We use the Union 2 and Loss datasets, by
using the well known preferred axis discussed in the literature, finding the
best fit reconstructed deceleration parameter. We found that a low redshift
transition of the reconstructed is clearly absent in one direction and
amazingly sharp in the opposite one. We discuss the possibility that such a
behavior can be associated with large scale structures affecting the data.Comment: 9 pages, 12 figure
Constraints on barotropic dark energy models by a new phenomenological parameterization
In this paper, we propose a new phenomenological two parameter
parametrization of to constrain barotropic dark energy models by
considering a spatially flat FRW universe, neglecting the radiation component,
and reconstructing the effective equation of state (EoS). This two
free-parameter EoS reconstruction shows a non-monotonic behavior, pointing to a
more general fitting for the scalar field models, like thawing and freezing
models. We constrain the free parameters using the observational data of
the Hubble parameter obtained from cosmic chronometers, the
joint-light-analysis type Ia Supernovae sample and a joint analysis from these
data. We obtain a value of today, , and
a transition redshift, (when the Universe
change from an decelerated phase to an accelerated one). The effective EoS
reconstruction and the - plane analysis pointed out a quintom
dark energy, which is consistent with a non parametric EoS reconstruction,
reported by other authors, and using the latest cosmological observations.Comment: This manuscript was accepted to be published in the European Physical
Journal C. 17 pages, 7 figures, 1 tabl
Quasar Microlensing Statistics and Flux-ratio Anomalies in Lens Models
Precise lens modeling is a critical step in time delay studies of multiply imaged quasars, which are key for measuring some important cosmological parameters (especially H0). However, lens models (in particular those semi-automatically generated) often show discrepancies with the observed flux ratios between the different quasar images. These flux-ratio anomalies are usually explained through differential effects between images (mainly microlensing) that alter the intrinsic magnification ratios predicted by the models. To check this hypothesis, we collect direct measurements of microlensing to obtain the histogram of microlensing magnifications. We compare this histogram with recently published model flux-ratio anomalies and conclude that they cannot be statistically explained by microlensing. The average value of the model anomalies (0.74 mag) significantly exceeds the mean impact of microlensing (0.33 mag). Moreover, the histogram of model anomalies presents a significant tail with high anomalies (∣Δm∣ ≥ 0.7 mag), which is completely unexpected from the statistics of microlensing observations. Microlensing simulations neither predict the high mean nor the fat tail of the histogram of model anomalies. We perform several statistical tests which exclude that microlensing can explain the observed flux-ratio anomalies (although Kolmogorov–Smirnov, which is less sensitive to the tail of the distributions, is not always conclusive). Thus, microlensing cannot statistically explain the bulk of flux-ratio anomalies, and models may explore different alternatives to try to reduce them. In particular, we propose to complement photometric observations with accurate flux ratios of the broad emission lines obtained from integral field spectroscopy to check and, ideally, constrain lens models.Grants PID2020-118687
GBC33 and PID2020-118687GB-C31, financed by MCIN/AEI/10.13039/501100011033Projects FQM-108, P20_00334, and A-FQM-510-UGR20/FEDER, financed by Junta de AndalucíaANID Fondecyt Regular #1231418Centro
de Astrofísica de Valparaís
Adopción del comercio electrónico en Micro, Pequeñas y Medianas empresas
En el presente trabajo se estudian los factores asociados con la adopción del comercio electrónico, así como el nivel de preparación digital de las micro, pequeñas y medianas empresas (MiPyMEs) comerciales y de servicios de Córdoba, Argentina. Siendo aún escasos los trabajos empíricos publicados sobre el tema en Latinoamérica, representa un aporte al conocimiento del estado del arte del comercio electrónico en la región. Mediante un estudio exploratorio-descriptivo, a partir del modelo teórico desarrollado por Molla & Licker (2004), se incorporan nuevos indicadores que enriquecen el modelo y el análisis de los resultados. Los datos provienen de una encuesta implementada a 108 empresas de la ciudad de Córdoba y alrededores, entre septiembre de 2012 y febrero de 2013. Los principales resultados señalan cómo los factores que más inciden en las diferencias en los niveles de adopción del comercio electrónico son el tamaño de las empresas y su nivel de madurez en la implementación de tecnologías de información (TIC).This paper addresses the study the factors associated with the adoption of e-commerce and e-readiness level onmicro, small and medium-sized commercial and service’s companies located in Córdoba, Argentina. Since there are still few empi- rical studies published on the subject in Latin America, this paper represents a contribution to the knowledge of the state of the art of e-commerce in the region. Taking as a starting point the theoretical model developed by Molla &Licker (2004), an exploratory- descriptive study is performed. New indicators are proposedin order to enrich the model and the analysis of the results. The data come from a survey implemented into 108 companies in Córdoba city area, between September 2012 and February 2013. The main results indicate that the size of the companies and their level of maturity or experience in the adoption of Information and Communication Technologies (ITC) are the two most influential factors on the differences at the levels of adoption of e-commerce in the enterprises.Fil: Jones, Carola. Universidad Nacional de Cordoba. Facultad de Cs.Economicas; Argentina;Fil: Alderete, Maria Veronica. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Investigaciones Economicas y Sociales del Sur; Argentina; Universidad Nacional del Sur. Departamento de Economia; Argentina;Fil: Motta, Jorge Jose. Universidad Nacional de Cordoba. Facultad de Cs.Economicas; Argentina
Real-world data mining meets clinical practice: Research challenges and perspective
As Big Data Analysis meets healthcare applications, domain-specific challenges and opportunities materialize in all aspects of data science. Advanced statistical methods and Artificial Intelligence (AI) on Electronic Health Records (EHRs) are used both for knowledge discovery purposes and clinical decision support. Such techniques enable the emerging Predictive, Preventative, Personalized, and Participatory Medicine (P4M) paradigm. Working with the Infectious Disease Clinic of the University Hospital of Modena, Italy, we have developed a range of Data-Driven (DD) approaches to solve critical clinical applications using statistics, Machine Learning (ML) and Big Data Analytics on real-world EHRs. Here, we describe our perspective on the challenges we encountered. Some are connected to medical data and their sparse, scarce, and unbalanced nature. Others are bound to the application environment, as medical AI tools can affect people's health and life. For each of these problems, we report some available techniques to tackle them, present examples drawn from our experience, and propose which approaches, in our opinion, could lead to successful real-world, end-to-end implementations.
DESY report number: DESY-22-153
Indicadores para medir el trabajo grupal en una feria de productores de la agricultura familiar
En 2014 comenzó a ejecutarse el PROFAM “Frutos de la tierra y el río: valorización de los emprendimientos de la agricultura familiar en el territorio Costa del Paraná, Provincia de Buenos Aires” . El mismo buscaba aportar a una experiencia de feria comenzada el año anterior, con la participación de distintas instituciones vinculadas a la agricultura familiar de San Pedro y Baradero. El aporte disciplinar del trabajo social en el marco de una pasantía de formación, permitió generar una herramienta para medir las transformaciones que se estaban dando en los protagonistas de la experiencia. El dispositivo fue ajustado en un equipo interdisciplinar, y validado a través de los años de la experiencia. El objetivo de este documento es explicar el modelo construido incluyendo los ajustes realizados en la validación del caso y sintetizar visualmente los resultados de su aplicación. El modelo puede adaptarse para su uso en otros casos donde se desee medir la interacción grupal en un proceso de feria.EEA San PedroFil: Motta, Anabela. Pasante PROCAGRA; ArgentinaFil: Marcozzi, Paula. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Piola, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Hansen, Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Liljesthrom, Verónica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; Argentin
Studying structure formation and evolution with strong-lensing galaxy groups
We present the analysis of a sample of strong-lensing galaxy group candidates. Our main findings are: confirmation of group-scale systems, complex light distributions, presence of large-scale structures in their surroundings, and evidence of a strong-lensing bias in the mass-concentration relation. We also report the detection of the first 'Bullet group'
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