163 research outputs found

    Estructuración bibliográfica acerca de Multiview learning para clasificación de imágenes

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    This article shows a bibliographic review of the academic literature related to "Image classification with Multiview learning" together with an analysis of the information present in each of the reviewed bibliographic sources, to propose a conceptual basis, theoretical and statistical for research works that develop or contain this theme. In the same way, the way in which the MVL is approached in the different application scenarios, both academic and practical, is briefly presented.En el presente artículo se muestra una revisión bibliográfica de la literatura académica relacionada con “Clasificación de imágenes con Multiview learning” junto con un análisis de la información presente en cada una de las fuentes bibliográficas revisadas, con la finalidad de proponer una base conceptual, teórica y estadística para trabajos de investigación que desarrollen o contengan esta temática. De igual manera se presenta brevemente la forma en la que se aborda el MVL en los diferentes escenarios de aplicación tanto académicos como prácticos

    Multiple late-Pleistocene colonisation events of the Antarctic pearlwort Colobanthus quitensis (Caryophyllaceae) reveal the recent arrival of native Antarctic vascular flora

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    Aim: Antarctica's remote and extreme terrestrial environments are inhabited by only two species of native vascular plants. We assessed genetic connectivity amongst Antarctic and South American populations of one of these species, Colobanthus quitensis, to determine its origin and age in Antarctica. Location: Maritime Antarctic, sub‐Antarctic islands, South America. Taxon: Antarctic pearlwort Colobanthus quitensis (Caryophyllaceae). Methods: Four chloroplast markers and one nuclear marker were sequenced from 270 samples from a latitudinal transect spanning 21–68° S. Phylogeographic, population genetic and molecular dating analyses were used to assess the demographic history of C. quitensis and the age of the species in Antarctica. Results: Maritime Antarctic populations consisted of two different haplotype clusters, occupying the northern and southern Maritime Antarctic. Molecular dating analyses suggested C. quitensis to be a young (<1 Ma) species, with contemporary population structure derived since the late‐Pleistocene. Main conclusions: The Maritime Antarctic populations likely derived from two independent, late‐Pleistocene dispersal events. Both clusters shared haplotypes with sub‐Antarctic South Georgia, suggesting higher connectivity across the Southern Ocean than previously thought. The overall findings of multiple colonization events by a vascular plant species to Antarctica, and the recent timing of these events, are of significance with respect to future colonizations of the Antarctic Peninsula by vascular plants, particularly with predicted increases in ice‐free land in this area. This study fills a significant gap in our knowledge of the age of the contemporary Antarctic terrestrial biota. Adding to previous inferences on the other Antarctic vascular plant species (the grass Deschampsia antarctica), we suggest that both angiosperm species are likely to have arrived on a recent (late‐Pleistocene) time‐scale. While most major groups of Antarctic terrestrial biota include examples of much longer‐term Antarctic persistence, the vascular flora stands out as the first identified terrestrial group that appears to be of recent origin

    Mid-IR Luminosities and UV/Optical Star Formation Rates at z<1.4

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    UV continuum and mid-IR emission constitute two widely used star formation indicators at intermediate and high redshifts. We study 2430 galaxies with z<1.4 in the Extended Groth Strip with MIPS 24 mic observations from FIDEL, spectroscopy from DEEP2, and UV, optical, and near-IR photometry from AEGIS. The data are coupled with stellar population models and Bayesian SED fitting to estimate dust-corrected SFRs. In order to probe the dust heating from stellar populations of various ages, the derived SFRs were averaged over various timescales--from 100 Myr for "current" SFR to 1--3 Gyr for long-timescale SFRs. These SED-based UV/optical SFRs are compared to total infrared luminosities extrapolated from 24 mic observations. We find that for the blue, actively star forming galaxies the correlation between the IR luminosity and the UV/optical SFR shows a decrease in scatter when going from shorter to longer SFR-averaging timescales. We interpret this as the greater role of intermediate age stellar populations in heating the dust than what is typically assumed. This holds over the entire redshift range. Many so-called green valley galaxies are simply dust-obscured actively star-forming galaxies. However, there exist 24 mic-detected galaxies, some with L>10^11 L_sun, yet with little current star formation. For them a reasonable amount of dust absorption of stellar light is sufficient to produce the observed levels of IR. In our sample optical and X-ray AGNs do not contribute on average more than ~50% to the mid-IR luminosity, and we see no evidence for a large population of "IR excess" galaxies (Abridged).Comment: Accepted for publication in ApJ. Content identical to arXiv version 1. No color figure

    Percepción de la ciberseguridad: : ciberdelitos, normas legales y políticas de seguridad

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    The objective of the study is to establish a relationship between cybersecurity, cybercrimes, current legal regulations and cybersecurity policies associated with electronic and computer media in Panama, an online form was applied remotely during the months of June-July year 2022, to the faculty coordinators and professors who belong to the School of Informatics for Educational and Business Management in eight academic units, and who have specialized studies in the area of ??Administration of Information Centers, Auditing and Security of Information Systems. A percentage 92.59% responded to this instrument, which compiled the results of the years of academic benefits and services, teaching category and academic-professional training in the specialty area, as well as information related to cybersecurity policies and backups of important information. As a conclusive aspect, it was determined that 96.96% of the respondents fully agree that teaching actions are required in terms of cybersecurity policies applied to the use and management of computer equipment, technological resources and digital media.Con el objetivo de establecer una relación entre la ciberseguridad, los ciberdelitos, las normas legales vigentes y las políticas de ciberseguridad asociados a los medios electrónicos e informáticos en Panamá, se aplicó un formulario en línea de manera remota durante los meses de junio-julio del año 2022, a los coordinadores de facultad y profesores que pertenecen a la Escuela de Informática para la Gestión Educativa y Empresarial en ocho unidades académicas, que cuentan con estudios especializados en el área de Administración de Centros de Información, Auditoría y Seguridad de Sistemas de Información. El 92.59% respondieron dicho instrumento, el cual recopiló los resultados de los años de prestaciones y servicios académicos, categoría docente y la formación académico-profesional en el área de especialidad, así como información relacionada con políticas de ciberseguridad y respaldos de información importante. Como aspecto concluyente, se determinó que el 96.96% de los encuestados está totalmente de acuerdo que se requieren de acciones de docencia en materia de políticas de ciberseguridad aplicadas al uso y manejo de los equipos informáticos, recursos tecnológicos y medios de comunicación digital

    Percepción de la ciberseguridad:

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    Con el objetivo de establecer una relación entre la ciberseguridad, los ciberdelitos, las normas legales vigentes y las políticas de ciberseguridad asociados a los medios electrónicos e informáticos en Panamá, se aplicó un formulario en línea de manera remota durante los meses de junio-julio del año 2022, a los coordinadores de facultad y profesores que pertenecen a la Escuela de Informática para la Gestión Educativa y Empresarial en ocho unidades académicas, que cuentan con estudios especializados en el área de Administración de Centros de Información, Auditoría y Seguridad de Sistemas de Información. El 92.59% respondieron dicho instrumento, el cual recopiló los resultados de los años de prestaciones y servicios académicos, categoría docente y la formación académico-profesional en el área de especialidad, así como información relacionada con políticas de ciberseguridad y respaldos de información importante. Como aspecto concluyente, se determinó que el 96.96% de los encuestados está totalmente de acuerdo que se requieren de acciones de docencia en materia de políticas de ciberseguridad aplicadas al uso y manejo de los equipos informáticos, recursos tecnológicos y medios de comunicación digital

    Galaxy Zoo: The Environmental Dependence of Bars and Bulges in Disc Galaxies

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    We present an analysis of the environmental dependence of bars and bulges in disc galaxies, using a volume-limited catalogue of 15810 galaxies at z<0.06 from the Sloan Digital Sky Survey with visual morphologies from the Galaxy Zoo 2 project. We find that the likelihood of having a bar, or bulge, in disc galaxies increases when the galaxies have redder (optical) colours and larger stellar masses, and observe a transition in the bar and bulge likelihoods, such that massive disc galaxies are more likely to host bars and bulges. We use galaxy clustering methods to demonstrate statistically significant environmental correlations of barred, and bulge-dominated, galaxies, from projected separations of 150 kpc/h to 3 Mpc/h. These environmental correlations appear to be independent of each other: i.e., bulge-dominated disc galaxies exhibit a significant bar-environment correlation, and barred disc galaxies show a bulge-environment correlation. We demonstrate that approximately half (50 +/- 10%) of the bar-environment correlation can be explained by the fact that more massive dark matter haloes host redder disc galaxies, which are then more likely to have bars. Likewise, we show that the environmental dependence of stellar mass can only explain a small fraction (25 +/- 10%) of the bar-environment correlation. Therefore, a significant fraction of our observed environmental dependence of barred galaxies is not due to colour or stellar mass dependences, and hence could be due to another galaxy property. Finally, by analyzing the projected clustering of barred and unbarred disc galaxies with halo occupation models, we argue that barred galaxies are in slightly higher-mass haloes than unbarred ones, and some of them (approximately 25%) are satellite galaxies in groups. We also discuss implications about the effects of minor mergers and interactions on bar formation.Comment: 20 pages, 18 figures; references updated; published in MNRA

    Trisubstituted Pyrimidines as Efficacious and Fast-acting Antimalarials

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    In this paper we describe the optimization of a phenotypic hit against Plasmodium falciparum, based on a trisubstituted pyrimidine scaffold. This led to compounds with good pharmacokinetics and oral activity in a P. berghei mouse model of malaria. The most promising compound (13) showed a reduction in parasitemia of 96% when dosed at 30 mg/kg orally once a day for 4 days in the P. berghei mouse model of malaria. It also demonstrated a rapid rate of clearance of the erythrocytic stage of P. falciparum in the SCID mouse model with an ED90 of 11.7 mg/kg when dosed orally. Unfortunately, the compound is a potent inhibitor of cytochrome P450 enzymes, probably due to a 4-pyridyl substituent. Nevertheless, this is a lead molecule with a potentially useful antimalarial profile, which could either be further optimized or be used for target hunting

    Galaxy Zoo: Quantifying Morphological Indicators of Galaxy Interaction

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    We use Galaxy Zoo 2 visual classifications to study the morphological signatures of interaction between similar-mass galaxy pairs in the Sloan Digital Sky Survey. We find that many observable features correlate with projected pair separation; not only obvious indicators of merging, disturbance and tidal tails, but also more regular features, such as spiral arms and bars. These trends are robustly quantified, using a control sample to account for observational biases, producing measurements of the strength and separation scale of various morphological responses to pair interaction. For example, we find that the presence of spiral features is enhanced at scales < 70 h^-1 kpc, probably due to both increased star formation and the formation of tidal tails. On the other hand, the likelihood of identifying a bar decreases significantly in pairs with separations < 30 h^-1 kpc, suggesting that bars are suppressed by close interactions between galaxies of similar mass. We go on to show how morphological indicators of physical interactions provide a way of significantly refining standard estimates for the frequency of close pair interactions, based on velocity offset and projected separation. The presence of loosely wound spiral arms is found to be a particularly reliable signal of an interaction, for projected pair separations up to ~100 h^-1 kpc. We use this indicator to demonstrate our method, constraining the fraction of low-redshift galaxies in truly interacting pairs, with M_* > 10^9.5 M_Sun and mass ratio < 4, to be between 0.4 - 2.7 per cent.Comment: Accepted to MNRAS on November 12, 201
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