310 research outputs found

    Towards Portability of Models for Predicting Students’ Final Performance in University Courses Starting from Moodle Logs

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    Predicting students’ academic performance is one of the older challenges faced by the educational scientific community. However, most of the research carried out in this area has focused on obtaining the best accuracy models for their specific single courses and only a few works have tried to discover under which circumstances a prediction model built on a source course can be used in other different but similar courses. Our motivation in this work is to study the portability of models obtained directly from Moodle logs of 24 university courses. The proposed method intends to check if grouping similar courses by the degree or the similar level of usage of activities provided by the Moodle logs, and if the use of numerical or categorical attributes affect in the portability of the prediction models. We have carried out two experiments by executing the well-known classification algorithm over all the datasets of the courses in order to obtain decision tree models and to test their portability to the other courses by comparing the obtained accuracy and loss of accuracy evaluation measures. The results obtained show that it is only feasible to directly transfer predictive models or apply them to different courses with an acceptable accuracy and without losing portability under some circumstances

    The Arabidopsis Polycomb Repressive Complex 1 (PRC1) components AtBMI1A, B and C impact gene networks throughout all stages of plant development.

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    Polycomb Group regulation in Arabidopsis (Arabidopsis thaliana) is required to maintain cell differentiation and allow developmental phase transitions. This is achieved by the activity of three PcG repressive complex 2s (PRC2s) and the participation of a yet poorly defined PRC1. Previous results showed that apparent PRC1 components perform discrete roles during plant development, suggesting the existence of PRC1 variants; however, it is not clear in how many processes these components participate. We show that AtBMI1 proteins are required to promote all developmental phase transitions and to control cell proliferation during organ growth and development, expanding their proposed range of action. While AtBMI1 function during germination is closely linked to B3 domain transcription factors VAL1/2 possibly in combination with GT-box binding factors, other AtBMI1 regulatory networks require participation of different factor combinations. Conversely, EMF1 and LHP1 bind many H3K27me3 positive genes up-regulated in atbmi1a/b/c mutants; however, loss of their function affects expression of a different subset, suggesting that even if EMF1, LHP1, and AtBMI1 exist in a common PRC1 variant, their role in repression depends on the functional context

    Arabidopsis SWC4 Binds DNA and Recruits the SWR1 Complex to Modulate Histone H2A.Z Deposition at Key Regulatory Genes

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    Deposition of the H2A.Z histone variant by the SWR1 complex (SWR1-C) in regulatory regions of specific loci modulates transcription. Characterization of mutations in Arabidopsis thaliana homologs of yeast SWR1-C has revealed a role for H2A.Z exchange in a variety of developmental processes. Nevertheless, the exact composition of plant SWR1-C and how it is recruited to target genes remains to be established. Here we show that SWC4, the Arabidopsis homolog of yeast SANT domain protein Swc4/Eaf2, is a DNA-binding protein that interacts with SWR1-C subunits. We demonstrate that the swc4-1 knockout mutant is embryo-lethal, while SWC4 RNAi knockdown lines display pleiotropic phenotypic alterations in vegetative and reproductive traits, including acceleration of flowering time, indicating that SWC4 controls post-embryonic processes. Transcriptomic analyses and genome-wide profiling of H2A.Z indicate that SWC4 represses transcription of a number of genes, including the floral integrator FT and key transcription factors, mainly by modulating H2A.Z deposition. Interestingly, SWC4 silencing does not affect H2A.Z deposition at the FLC locus nor expression of this gene, a master regulator of flowering previously shown to be controlled by SWR1-C. Importantly, we find that SWC4 recognizes specific AT-rich DNA elements in the chromatin regions of target genes and that SWC4 silencing impairs SWR1-C binding at FT. Collectively, our data suggest that SWC4 regulates plant growth and development by aiding SWR1-C recruitment and modulating H2A.Z deposition.This work was supported by grants BIO2010-15589, BIO2013-43098-R, and BIO2016-77559-R to J.A.J. and M.P., and grant RYC-2013-14689 to P.C. from the Spanish Ministerio de Economia y Competitividad (MINECO/FEDER, EU), and Marie Curie FP7-PEOPLE-2011-IEF grant 298790 to P.C. and J.A.J. from the European Commission. The CBGP is a Severo Ochoa Center of Excellence (SEV-2016-0672). The CNIC is supported by the Spanish Ministerio de Economia, Industria y Competitividad and the Pro CNIC Foundation, and is also a Severo Ochoa Center of Excellence (SEV-2015-0505).S

    POSICIONAMIENTO WEB EN ATRACTIVOS TURÍSTICOS DEL CANTÓN SUCRE, ECUADOR

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    La presente investigaciĂłn realizĂł un anĂĄlisis de posicionamiento web a partir del entorno de los canales publicitarios digitales, ademĂĄs la evaluaciĂłn de la presencia online de los atractivos que posee el cantĂłn Sucre, para determinar la calidad o grado de optimizaciĂłn de los medios publicitarios empleados para su promociĂłn y la implementaciĂłn de acciones que permitan la difusiĂłn de la oferta turĂ­stica a travĂ©s de motores de bĂșsqueda mediante la utilizaciĂłn de estrategias OptimizaciĂłn para Motores de BĂșsqueda (SEO) y Marketing en Buscadores (SEM) que mejoren la visibilidad de sitios web orientados a la promociĂłn turĂ­stica; la mejora de visibilidad en medios sociales populares como Facebook, YouTube, Twitter e Instagram mediante la utilizaciĂłn de tĂ©cnicas de Marketing en Medios Sociales (SMM) y OptimizaciĂłn en Medios Sociales (SMO). El uso de marketing mĂłvil a travĂ©s de aplicaciones destinadas a brindar informaciĂłn turĂ­stica de los atractivos, la captaciĂłn de emails para el desarrollo de marketing por correo electrĂłnico y la ejecuciĂłn de campañas de publicidad pagada en internet, destacando ademĂĄs las grandes ventajas competitivas y oportunidades de crecimiento sostenido que brinda la utilizaciĂłn de los medios digitales en relaciĂłn con los medios publicitarios tradicionales en costos, alcance, usabilidad y mediciĂłn de resultados.PALABRAS CLAVE: Posicionamiento web; atractivos; medios publicitarios; marketing digital; motores de bĂșsquedas.WEB POSITIONING IN CANTON SUCRE TOURIST ATTRACTIONS, ECUADORABSTRACTThe present research carried out a web positioning analysis based on the environment of the digital advertising channels, besides the evaluation of the online presence of the attractions that has the canton Sucre, to determine the quality or degree of optimization of the publicity means employed for its Promotion and implementation of actions that allow the dissemination of tourism through search engines through the use of search engine optimization (SEO) and Search Engine Marketing (SEM) strategies that improve the visibility of web sites oriented to the Tourist promotion; Improving visibility on popular social media such as Facebook, YouTube, Twitter and Instagram through the use of Social Media Marketing (SMM) and Social Media Optimization (SMO) techniques. The use of mobile marketing through applications designed to provide tourist information about attractiveness, the capture of emails for the development of email marketing and the execution of paid advertising campaigns on the Internet, also highlighting the great competitive advantages and opportunities of Sustained growth in the use of digital media in relation to traditional advertising media in terms of costs, scope, usability and results measurement.KEYWORDS: Web positioning; Attractive; Advertising media; digital marketing; Search engines

    Liver injury in non-alcoholic fatty liver disease is associated with urea cycle enzyme dysregulation

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    The main aim was to evaluate changes in urea cycle enzymes in NAFLD patients and in two preclinical animal models mimicking this entity. Seventeen liver specimens from NAFLD patients were included for immunohistochemistry and gene expression analyses. Three-hundred-and-eighty-two biopsy-proven NAFLD patients were genotyped for rs1047891, a functional variant located in carbamoyl phosphate synthetase-1 (CPS1) gene. Two preclinical models were employed to analyse CPS1 by immunohistochemistry, a choline deficient high-fat diet model (CDA-HFD) and a high fat diet LDLr knockout model (LDLr −/−). A significant downregulation in mRNA was observed in CPS1 and ornithine transcarbamylase (OTC1) in simple steatosis and NASH-fibrosis patients versus controls. Further, age, obesity (BMI > 30 kg/m2), diabetes mellitus and ALT werefound to be risk factors whereas A-allele from CPS1 was a protective factor from liver fibrosis. CPS1 hepatic expression was diminished in parallel with the increase of fibrosis, and its levels reverted up to normality after changing diet in CDA-HFD mice. In conclusion, liver fibrosis and steatosis were associated with a reduction in both gene and protein expression patterns of mitochondrial urea cycle enzymes. A-allele from a variant on CPS1 may protect from fibrosis development. CPS1 expression is restored in a preclinical model when the main trigger of the liver damage disappears

    Freshwater fishes and water status in Mexico: A country-wide appraisal.

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    Mexico is the southernmost country in North America, and extends into Central America, south of the Isthmus of Tehuantepec. The northern half of M®exico is located on the Temperate belt and is arid in character (Nearctic), while the rest is within the Tropical belt (Neotropical). Climate varies from extremely temperate desert in the north, to tropical humid in the south.M®exico has more than 500 freshwater fish species, about 271 of them country endemics, and approximately 48 endemics from binational basins. There are still some 30–40 fish species not yet described. There are 563 fish species colonizing coastal flood plain species. In addition to the numbers of colonizing fishes, the burden of introduced exotics has also been growing. In 1904, only 4 species were recognized as exotics; by 1997 the number had increased to 94, and by 2008 to 11

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon Ό\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, ΌΌ\mu\mu or eΌe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction
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