1,528 research outputs found

    Two Tests for Dependence (of Unknown Form) between Time Series

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    This paper proposes two new nonparametric tests for independence between time series. Both tests are based on symbolic analysis, specifically on symbolic correlation integral, in order to be robust to potential unknown nonlinearities. The first test is developed for a scenario in which each considered time series is independent and therefore the interest is to ascertain if two internally independent time series share a relationship of an unknown form. This is especially relevant as the test is nuisance parameter free, as proved in the paper. The second proposed statistic tests for independence among variables, allowing these time series to exhibit within-dependence. Monte Carlo experiments are conducted to show the empirical properties of the tests.This research is the result of the activity performed under the program Groups of Excellence of the Region of Murcia, the Fundación Seneca, Science and Technology Agency of the region of Murcia project under grant 19884/GERM/15. All remaining errors are our responsibility

    Transference Impedance Estimation of IEC60318 Couplers by Image Processing and finite Element Modelling

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    In order to know the acoustic transference impedance of acoustic coupler described in IEC60318 standard it is necessary to make measures based on the reciprocity technique. This technique is used for microphones calibration as is defined in IEC61094-2 standard. This calibration method is complex enough to execute, and therefore it would be very interesting to look for alternative procedures that allow knowing the coupler acoustic impedance. In this paper an acoustic impedance calibration methodfor type I coupler is proposed based on non invasive X-ray inspection, virtual instrumentation image processing application and computer simulation. This new approach requires knowing the coupler's geometry and use offinite element model approach for acoustic coupler behavior determination. In order to establish a precise mechanical model of the couplers described in IEC60318 standard it is necessary to know the geometry and key dimensions of the coupler. These dimensions are obtained with non-invasive measurement techniques, based on X-ray inspection. Then the use of a finite element model allows prediction of the coupler acoustic impedance values. This modeling is quite differentfrom the "lumped parameter model" proposed in the IEC60318 standard Lumped parameter modeling has limitations in its application because the dimensions of the coupler's elements are comparable with the acoustic signal wavelength. Moreover, when the sound propagates in narrow cavities and ducts the losses produced by viscosity and thermal effects must be taken into account. All these effects are not reflected with accuracy in the classic lumped model. The result of finite element simulation can provide more detailed information about the interior acoustic behavior of the coupler and therefore provide a more realistic and accurate value of acoustic impedance in order to calibrate the device. The comparison of the data obtained with this new approach and the values defined in the current version of IEC60318-1 standard (291633/CDV) confirm the validity ofthe method

    CB2 cannabinoid receptor activation promotes colon cancer progression via AKT/GSK3β signaling pathway

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    The pharmacological activation of the cannabinoid receptor type 2, CB2, has been shown to elicit anti-tumoral mechanisms in different cancer types. However, little is known about its endogenous role in tumor pathophysiology, and different studies have attributed pro-tumorigenic properties to this receptor. In a previous work, we showed that CB2 expression is a poor prognostic factor in colon cancer patients. Here we report that activation of CB2 with low doses of specific agonists induce cell proliferation and favor the acquisition of aggressive molecular features in colon cancer cells. We show that sub-micromolar concentrations of CB2-specific agonists, JWH-133 and HU-308, promote an increase in cell proliferation rate through the activation of AKT/PKB pathway in colon cancer in vitro and in vivo. AKT activation promotes GSK3β inhibition and thus, a more aggressive cell phenotype with the subsequent elevation of SNAIL levels, E-cadherin degradation and β-catenin delocalization from cell membrane. Taken together, our data show that CB2 activation with sub-micromolar doses of agonists, which could be more similar to endogenous levels of cannabinoids, promote colon cancer progression, implicating that CB2 could have a pro-tumorigenic endogenous role in colon cancerThis work was supported by grants from Fondo de Investigaciones Sanitarias (ISCIII-PI10/00879 to JMG; Plan Nacional de I+D+I 2008-2011, FEDER funds co-financed), Red Temática de Investigación Cooperativa en Cáncer (ISCIII-RETIC RD12/0036/0041; Plan Estatal de I+D+I 2013-2016, FEDER funds cofinanced). JMG and PM were supported by ISCIII CP08/00217 and JR14/0018 contracts, respectively. EMM was recipient of ISCIII PFIS PhD studentship (FI11/00696) (Plan Nacional de I+D+I 2008-2011, FEDER funds co-financed); AMR was recipient of PhD contract from Department of Medical Oncology of H.U. Puerta de Hierro; VC was recipient of attending physician contract in Medical Oncology Department from H.U. Puerta de Hierro; MP was supported by Universidad Autónoma de Madrid (UAM) with Full Professor contrac

    Calibration of semi-analytic models of galaxy formation using Particle Swarm Optimization

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    We present a fast and accurate method to select an optimal set of parameters in semi-analytic models of galaxy formation and evolution (SAMs). Our approach compares the results of a model against a set of observables applying a stochastic technique called Particle Swarm Optimization (PSO), a self-learning algorithm for localizing regions of maximum likelihood in multidimensional spaces that outperforms traditional sampling methods in terms of computational cost. We apply the PSO technique to the SAG semi-analytic model combined with merger trees extracted from a standard Λ\LambdaCDM N-body simulation. The calibration is performed using a combination of observed galaxy properties as constraints, including the local stellar mass function and the black hole to bulge mass relation. We test the ability of the PSO algorithm to find the best set of free parameters of the model by comparing the results with those obtained using a MCMC exploration. Both methods find the same maximum likelihood region, however the PSO method requires one order of magnitude less evaluations. This new approach allows a fast estimation of the best-fitting parameter set in multidimensional spaces, providing a practical tool to test the consequences of including other astrophysical processes in SAMs.Comment: 11 pages, 4 figures, 1 table. Accepted for publication in ApJ. Comments are welcom

    Do You See What I See? Effectiveness of 360-Degree vs. 2D Video Ads Using a Neuroscience Approach

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    [EN] This study compares cognitive and emotional responses to 360-degree vs. static (2D) videos in terms of visual attention, brand recognition, engagement of the prefrontal cortex, and emotions. Hypotheses are proposed based on the interactivity literature, cognitive overload, advertising response model and motivation, opportunity, and ability theoretical frameworks, and tested using neurophysiological tools: electroencephalography, eye-tracking, electrodermal activity, and facial coding. The results revealed that gaze view depends on ad content, visual attention paid being lower in 360-degree FMCG ads than in 2D ads. Brand logo recognition is lower in 360-degree ads than in 2D video ads. Overall, 360-degree ads for durable products increase positive emotions, which carries the risk of non-exposure to some of the ad content. In testing four ads for durable goods and fast-moving consumer goods (FMCG) this research explains the mechanism through which 360-degree video ads outperform standard versionsThis work was supported by the Generalitat Valenciana funded project "Rebrand", grant number PROMETEU/2019/105, and by the European Regional Development Fund program of the Valencian Community 2014-2020 project "Interfaces de realidad mixta aplicada a salud y toma de decisiones", grant number IDIFEDER/2018/029.Ausin-Azofra, JM.; Bigné, E.; Ruiz, C.; Marín-Morales, J.; Guixeres Provinciale, J.; Alcañiz Raya, ML. (2021). Do You See What I See? Effectiveness of 360-Degree vs. 2D Video Ads Using a Neuroscience Approach. Frontiers in Psychology. 12:1-14. https://doi.org/10.3389/fpsyg.2021.612717S1141

    Advanced data acquisition system implementation for the ITER Neutron Diagnostic use case using EPICS and FlexRIO technology on a PXIe platform

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    In the framework of the ITER Control Breakdown Structure (CBS), Plant System Instrumentation & Control (I&C) defines the hardware and software required to control one or more plant systems [1]. For diagnostics, most of the complex Plant System I&C are to be delivered by ITER Domestic Agencies (DAs). As an example for the DAs, ITER Organization (IO) has developed several use cases for diagnostics Plant System I&C that fully comply with guidelines presented in the Plant Control Design Handbook (PCDH) [2]. One such use case is for neutron diagnostics, specifically the Fission Chamber (FC), which is responsible for delivering time-resolved measurements of neutron source strength and fusion power to aid in assessing the functional performance of ITER [3]. ITER will deploy four Fission Chamber units, each consisting of three individual FC detectors. Two of these detectors contain Uranium 235 for Neutron detection, while a third "dummy" detector will provide gamma and noise detection. The neutron flux from each MFC is measured by the three methods: . Counting Mode: measures the number of individual pulses and their location in the record. Pulse parameters (threshold and width) are user configurable. . Campbelling Mode (Mean Square Voltage): measures the RMS deviation in signal amplitude from its average value. .Current Mode: integrates the signal amplitude over the measurement perio

    Arterial stiffness is associated with adipokine dysregulation in non-hypertensive obese mice

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    This is the peer reviewed version of the following article: Vascular Pharmacology 77 (2016): 38-47, which has been published in final form at http://dx.doi.org/10.1016/j.vph.2015.05.012The aim of this study was to characterize alterations in vascular structure and mechanics in murine mesenteric arteries from obese non-hypertensive mice, as well as their relationship with adipokines. Four-week old C57BL/6J male mice were assigned either to a control (C, 10% kcal from fat) or a high-fat diet (HFD, 45% kcal from fat) for 32 weeks. HFD animals weighed 30% more than controls (p < 0.001), exhibited similar blood pressure, increased leptin, insulin and superoxide anion (O2radical dot−) levels, and reduced adiponectin levels and nitric oxide (NO) bioavailability. Arterial structure showed an outward remodeling with an increase in total number of both adventitial and smooth muscle cells in HFD. Moreover, HFD mice exhibited an increased arterial stiffness assessed by β-values (C = 2.4 ± 0.5 vs HFD = 5.3 ± 0.8; p < 0.05) and aortic pulse wave velocity (PWV, C = 3.4 ± 0.1 vs HFD = 3.9 ± 0.1; p < 0.05). β-Values and PWV positively correlated with leptin, insulin or O2radical dot− levels, whereas they negatively correlated with adiponectin levels and NO bioavailability (p < 0.01). A reduction in fenestrae number together with an increase in type-I collagen amount (p < 0.05) were observed in HFD. These data demonstrate that HFD accounts for the development of vascular remodeling and arterial stiffness associated with adipokine dysregulation and oxidative stress, independently of hypertension developmentThis work was supported by grants from Ministerio de Ciencia e Investigación (BFU2011-25303), Ministerio de Economía y Competitividad (SAF2009-09714, SAF2011-25303, BFU2012-35353), Grupos Universidad Complutense de Madrid (UCM; GR-921641), Fundación Universitaria CEU-San Pablo, Fundación Mutua Madrileña and Sociedad para el Estudio de la Salud Cardiometabólica (SESCAMET). MGO is recipient of a Ministerio de Educación y Ciencia fellowshi

    Car-following techniques: reconsidering the role of the human factor

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    Keeping correct distance between vehicles is a fundamental tenet in road traffic. New road signs and markings appearing on motorways aid drivers in determining this distance. However, the ‘Nagoya experiment’ (Sugiyama et al., 2008) revealed correct distance made following safe while also eventually destabilizing traffic flow. When traffic becomes dense, most drivers keep the minimum safety distance and brake when the vehicle ahead decelerates. The resultant chain reaction along the entire line of closely following vehicles causes for no apparent reason a traffic stoppage, known as a ‘phantom’ or ‘shockwave’ jam. The car-following models of Sugiyama et al. found certain speeds, traffic densities, and inter-vehicular distances combined to congest traffic. Drawing upon these and other phenomena (e.g., wave movement in Nature), car following by Driving to keep Inertia (DI) was conceived by us as an alternative to Driving to keep Distance (DD). Three studies explored possible prevention of ‘phantom’ jams by adopting DI. Using a driving simulator, affective and behavioural measures were taken (N=113). The results comparing the efficiency of DI vs. DD are summarized. DI promoted a more stable driver trajectory, in cognitive-affective and behavioural terms, and lowered fuel consumption by about 20%

    Identification of the design variables of e-learning tools using concept mapping techniques

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    Thanks to the use of stadisthic techniques is posible to stablish an technological acceptation model of e- Learning tools. This article describes the application of concept mapping techniques to identify the most relevant extern variables on the design process of an e-learning tool and a reliability analisys of the concept map obtained as result of the experimen

    Identification of Designing Variable of an Elearning Tool

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    En este artículo se muestran, a través de mapas bidimensionales, los resultados procedentes de un proyecto de investigación mediante el cual se han identificado las variables externas a tener en cuenta en el diseño de una herramienta de eLearning para conseguir evaluar, posteriormente, su uso real. La técnica empleada para ello es la "Elaboración de mapas conceptuales". Asimismo, se observa la necesidad de tener en cuenta cómo llevar a cabo la gestión de la herramienta por parte del usuario. Finalmente, se ha analizado la fiabilidad de nuestros mapasIn this paper the results from a research project1 are shown. A scientific technique called "Concept Mapping Process" has been used to identify the external variables to be kept in mind in the design of an eLearning tool, in order to evaluate its true usage later. Results are shown through two-dimensional maps. Another important result is the necessity of designing tools to carry out the management of the tool on the part of the user. Finally, there has been analysed the reliability of our mapsMinisterio de Educación y Ciencia EA2005-017
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