205 research outputs found

    Análisis predictivo de la crypto moneda monero

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    El mercado de las crypto monedas ha crecido en los últimos años siendo la más conocida Bitcoin, pero se han creado otras crypto monedas con las características de encriptar todo tipo de transacción como lo es Monero (XMR). Utilizando esta crypto moneda vamos a identificar primero si la serie presenta un comportamiento estocástico o determinístico utilizando el método de surrogate data testing y por último conociendo una aproximación a la estructura de la serie vamos a predecir diferentes intervalos de tiempo para corroborar si nuestro modelo identifica adecuadamente la tendencia de la serie. Al realizar el método de surrogate data testing encontramos que los resultados obtenidos no fueron concluyentes utilizando diferentes estadísticos como Nolinear Prediction y Entropy complexity sobre la serie, por tal motivo no podemos afirmar que la serie se comporta como un proceso no lineal debido a este resultado realizamos una estimación lineal estocástica de la serie divida en dos periodos pues se encontró que la estructura de la serie fue afectada por la pandemia covid-19. Utilizando el último periodo comprendido desde 2020-03-12 hasta 2020-10-18 se obtuvo un modelo auto regresivo de orden uno AR(1), el cual explicaba adecuadamente la serie y cumpliendo con los supuestos del modelo además se realizaron predicciones para diferentes días desde 20202-10-20 comparando con los datos reales del mercado, el resultado obtenido fue la correcta identificación de la tendencia de la serie, la cual se encontraba en los intervalos de confianza considerados.The Crypto market has grown in the last years with different types of currencies, some of them are transaction public and other encrypted like Monero (XMR). Using this crypto currency, we want to identify if his behavior is described by a linear stochastic process or a deterministic no linear process using surrogate data testing and based on that create a model to predict the behavior of the series. The result obtained by the surrogate data testing method using Nolinear Prediction and Entropy complexity statistics were not conclusive, this shows us that an approximation of the underling process is not deterministic no-linear process based on that we model the series with a linear stochastic process and we found the necessity to split the series in two parts before COVID-19 and after because this event affected drastically the market behavior. The final model is an Auto Regressive with one lag using data from 2020-03-12 to 2020-10-18 being able to correctly identify the tendency of the Monero series in different time points

    Search for the standard model Higgs boson produced in association with top quarks and decaying into a bbˉb\bar{b} pair in pppp collisions at s\sqrt{s} = 13  TeV with the ATLAS detector

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    A search for the standard model Higgs boson produced in association with a top-quark pair, tt¯H, is presented. The analysis uses 36.1  fb-1 of pp collision data at s=13  TeV collected with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The search targets the H→bb¯ decay mode. The selected events contain either one or two electrons or muons from the top-quark decays, and are then categorized according to the number of jets and how likely these are to contain b-hadrons. Multivariate techniques are used to discriminate between signal and background events, the latter being dominated by tt¯+jets production. For a Higgs boson mass of 125 GeV, the ratio of the measured tt¯H signal cross-section to the standard model expectation is found to be μ=0.84-0.61+0.64. A value of μ greater than 2.0 is excluded at 95% confidence level (C.L.) while the expected upper limit is μ<1.2 in the absence of a tt¯H signal.Peer Reviewe

    Performance of the ATLAS Track Reconstruction Algorithms in Dense Environments in LHC Run 2

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    With the increase in energy of the Large Hadron Collider to a centre-of-mass energy of 13  TeV\text {TeV} for Run 2, events with dense environments, such as in the cores of high-energy jets, became a focus for new physics searches as well as measurements of the Standard Model. These environments are characterized by charged-particle separations of the order of the tracking detectors sensor granularity. Basic track quantities are compared between 3.2 fb−1^{-1} of data collected by the ATLAS experiment and simulation of proton–proton collisions producing high-transverse-momentum jets at a centre-of-mass energy of 13  TeV\text {TeV} . The impact of charged-particle separations and multiplicities on the track reconstruction performance is discussed. The track reconstruction efficiency in the cores of jets with transverse momenta between 200 and 1600 GeV\text {GeV} is quantified using a novel, data-driven, method. The method uses the energy loss,  dE/dx{\text { d}}{} \textit{E}/d\textit{x} , to identify pixel clusters originating from two charged particles. Of the charged particles creating these clusters, the measured fraction that fail to be reconstructed is 0.061±0.006 (stat.)±0.014 (syst.)0.061 \pm 0.006\ {\text {(stat.)}} \pm 0.014\ {\text {(syst.)}} and 0.093±0.017 (stat.)±0.021 (syst.)0.093 \pm 0.017\ {\text {(stat.)}}\pm 0.021\ {\text {(syst.)}} for jet transverse momenta of 200–400  GeV\text {GeV} and 1400–1600  GeV\text {GeV} , respectively.Peer Reviewe

    Combined search for the Standard Model Higgs boson in pppp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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    A combined search for the Standard Model Higgs boson with the ATLAS detector at the LHC is presented. The datasets used correspond to integrated luminosities from 4.6 fb^-1 to 4.9 fb^-1 of proton-proton collisions collected at sqrt(s) = 7 TeV in 2011. The Higgs boson mass ranges of 111.4 GeV to 116.6 GeV, 119.4 GeV to 122.1 GeV, and 129.2 GeV to 541 GeV are excluded at the 95% confidence level, while the range 120 GeV to 560 GeV is expected to be excluded in the absence of a signal. An excess of events is observed at Higgs boson mass hypotheses around 126 GeV with a local significance of 2.9 standard deviations (sigma). The global probability for the background to produce an excess at least as significant anywhere in the entire explored Higgs boson mass range of 110-600 GeV is estimated to be ~15%, corresponding to a significance of approximately one sigma.Peer Reviewe

    Measurements of ttˉt\bar{t} differential cross-sections of highly boosted top quarks decaying to all-hadronic final states in pppp collisions at s=13 \sqrt{s}=13\, TeV using the ATLAS detector

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    Measurements are made of differential cross-sections of highly boosted pair-produced top quarks as a function of top-quark and tt¯ system kinematic observables using proton-proton collisions at a center-of-mass energy of s=13  TeV. The data set corresponds to an integrated luminosity of 36.1  fb-1, recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Events with two large-radius jets in the final state, one with transverse momentum pT>500  GeV and a second with pT>350  GeV, are used for the measurement. The top-quark candidates are separated from the multijet background using jet substructure information and association with a b-tagged jet. The measured spectra are corrected for detector effects to a particle-level fiducial phase space and a parton-level limited phase space, and are compared to several Monte Carlo simulations by means of calculated χ2 values. The cross-section for tt¯ production in the fiducial phase-space region is 292±7(stat)±71(syst)  fb, to be compared to the theoretical prediction of 384±36  fb.Peer Reviewe

    Measurement of charged-particle distributions sensitive to the underlying event in s=13 \sqrt{s}=13 TeV proton-proton collisions with the ATLAS detector at the LHC

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    We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb−1^{−1}. The distributions were constructed using charged particles with absolute pseudorapidity less than 2.5 and with transverse momentum greater than 500 MeV, in events with at least one such charged particle with transverse momentum above 1 GeV. These distributions characterise the angular distribution of energy and particle flows with respect to the charged particle with highest transverse momentum, as a function of both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are compared to the predictions of various Monte Carlo event generators, experimentally establishing the level of underlying-event activity at LHC Run 2 energies and providing inputs for the development of event generator modelling. The current models in use for UE modelling typically describe this data to 5% accuracy, compared with data uncertainties of less than 1%.Peer Reviewe

    Ciprofibrate therapy in patients with hypertriglyceridemia and low high density lipoprotein (HDL)-cholesterol: greater reduction of non-HDL cholesterol in subjects with excess body weight (The CIPROAMLAT study)

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    BACKGROUND: Hypertriglyceridemia in combination with low HDL cholesterol levels is a risk factor for cardiovascular disease. Our objective was to evaluate the efficacy of ciprofibrate for the treatment of this form of dyslipidemia and to identify factors associated with better treatment response. METHODS: Multicenter, international, open-label study. Four hundred and thirty seven patients were included. The plasma lipid levels at inclusion were fasting triglyceride concentrations between 1.6–3.9 mM/l and HDL cholesterol ≤ 1.05 mM/l for women and ≤ 0.9 mM/l for men. The LDL cholesterol was below 4.2 mM/l. All patients received ciprofibrate 100 mg/d. Efficacy and safety parameters were assessed at baseline and at the end of the treatment. The primary efficacy parameter of the study was percentage change in triglycerides from baseline. RESULTS: After 4 months, plasma triglyceride concentrations were decreased by 44% (p < 0.001). HDL cholesterol concentrations were increased by 10% (p < 0.001). Non-HDL cholesterol was decreased by 19%. A greater HDL cholesterol response was observed in lean patients (body mass index < 25 kg/m(2)) compared to the rest of the population (8.2 vs 19.7%, p < 0.001). In contrast, cases with excess body weight had a larger decrease in non-HDL cholesterol levels (-20.8 vs -10.8%, p < 0.001). There were no significant complications resulting from treatment with ciprofibrate. CONCLUSIONS: Ciprofibrate is efficacious for the correction of hypertriglyceridemia / low HDL cholesterol. A greater decrease in non-HDL cholesterol was found among cases with excess body weight. The mechanism of action of ciprofibrate may be influenced by the pathophysiology of the disorder being treated

    Measurement of the cross section for isolated-photon plus jet production in pppp collisions at s=13\sqrt s=13 TeV using the ATLAS detector

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    The dynamics of isolated-photon production in association with a jet in proton–proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb −1 . Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- kt algorithm with radius parameter R=0.4 and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements.Peer Reviewe
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