138 research outputs found

    Comparing Psychology Undergraduates' Performance in Probabilistic Reasoning under Verbal-Numerical and Graphical-Pictorial Problem Presentation Format: What is the Role of Individual and Contextual Dimensions?

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    This study aims to investigate about the existence of a graphical facilitation effect on probabilistic reasoning. Measures of undergraduates’ performances on problems presented in both verbal-numerical and graphical-pictorial formats have been related to visuo-spatial and numerical prerequisites, to statistical anxiety, to attitudes towards statistics and to the confidence in response correctness. Psychology undergraduates in Italy and Spain with no statistical expertise (N= 676) completed a protocol under conditions of presence versus absence of time pressure. Hierarchical linear regressions and ANCOVAs with mixed design have been carried out separately for each sample. The best predictor of performance in both formats has been the confidence in solution correctness under the condition of time pressure administration, which seemed to promote the commitment to the task. The findings suggest that the eventual occurrence of a graphical facilitation could be the result of a multifactorial interaction among contextual and individual dimensions, rather than being strictly related to the problem presentation format

    Validation of the CAchexia SCOre (CASCO). Staging cancer patients: The use of miniCASCO as a simplified tool

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    The CAchexia SCOre (CASCO) was described as a tool for the staging of cachectic cancer patients. The aim of this study is to show the metric properties of CASCO in order to classify cachectic cancer patients into three different groups, which are associated with a numerical scoring. The final aim was to clinically validate CASCO for its use in the classification of cachectic cancer patients in clinical practice. We carried out a case -control study that enrolled prospectively 186 cancer patients and 95 age-matched controls. The score includes five components: (1) body weight loss and composition, (2) inflammation/metabolic disturbances/immunosuppression, (3) physical performance, (4) anorexia, and (5) quality of life. The present study provides clinical validation for the use of the score. In order to show the metric properties of CASCO, three different groups of cachectic cancer patients were established according to the results obtained with the statistical approach used: mild cachexia (15 â\u89¤ Ã\u97 â\u89¤ 28), moderate cachexia (29 â\u89¤ Ã\u97 â\u89¤ 46), and severe cachexia (47 â\u89¤ Ã\u97 â\u89¤ 100). In addition, a simplified version of CASCO, MiniCASCO (MCASCO), was also presented and it contributes as a valid and easy-to-use tool for cachexia staging. Significant statistically correlations were found between CASCO and other validated indexes such as Eastern Cooperative Oncology Group (ECOG) and the subjective diagnosis of cachexia by specialized oncologists. A very significant estimated correlation between CASCO and MCASCO was found that suggests that MCASCO might constitute an easy and valid tool for the staging of the cachectic cancer patients. CASCO and MCASCO provide a new tool for the quantitative staging of cachectic cancer patients with a clear advantage over previous classifications

    Stand-alone hybrid power plant based on SiC solar PV and wind inverters with smart spinning reserve management

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    Stand-alone hybrid power plants based on renewable energy sources are becoming a more and more interesting alternative. However, their management is a complex task because there are many variables, requirements and restrictions as well as a wide variety of possible scenarios. Though a proper sizing of the power plant is necessary to obtain a competitive cost of the energy, smart management is key to guarantee the power supply at a minimum cost. In this work, a novel hybrid power plant control strategy is designed, implemented and simulated under a wide variety of scenarios. Thereby, the proposed control algorithm aims to achieve maximum integration of renewable energy, reducing the usage of non-renewable generators as much as possible and guaranteeing the stability of the microgrid. Different scenarios and case studies have been analyzed by dynamic simulation to verify the proper operation of the power plant controller. The main novelties of this work are: (i) the stand-alone hybrid power plant management regarding a battery energy storage system as a part of the spinning reserve, (ii) the characterization of the largest loads as non-priority loads, (iii) the minimization of the needed spinning reserve and fuel consumption from diesel generators

    Assessing probabilistic reasoning in verbal-numerical and graphical-pictorial formats: An evaluation of the psychometric properties of an instrument

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    Research on the graphical facilitation of probabilistic reasoning has been characterised by the effort expended to identify valid assessment tools. The authors developed an assessment instrument to compare reasoning performances when problems were presented in verbal-numerical and graphical-pictorial formats. A sample of undergraduate psychology students (n=676) who had not developed statistical skills, solved problems requiring probabilistic reasoning. They attended universities in Spain (n=127; f=71.7%) and Italy (n=549; f=72.9%). In Italy 173 undergraduates solved these problems under time pressure. The remaining students solved the problems without time limits. Classical Test Theory (CTT) and Item Response Theory (IRT) were applied to assess the effect of two formats and to evaluate criterion and discriminant validity. The instrument showed acceptable psychometric properties, providing preliminary evidence of validity

    Dynamics of excitable cells: spike-adding phenomena in action

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    We study the dynamics of action potentials of some electrically excitable cells: neurons and cardiac muscle cells. Bursting, following a fast–slow dynamics, is the most characteristic behavior of these dynamical systems, and the number of spikes may change due to spike-adding phenomenon. Using analytical and numerical methods we give, by focusing on the paradigmatic 3D Hindmarsh–Rose neuron model, a review of recent results on the global organization of the parameter space of neuron models with bursting regions occurring between saddle-node and homoclinic bifurcations (fold/hom bursting). We provide a generic overview of the different bursting regimes that appear in the parametric phase space of the model and the bifurcations among them. These techniques are applied in two realistic frameworks: insect movement gait changes and the appearance of Early Afterdepolarizations in cardiac dynamics

    Inspiratory fraction as a marker of skeletal muscle dysfunction in patients with COPD

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    AbstractBackgroundAn inspiratory capacity to total lung capacity (IC/TLC) ratio of ≤25% has emerged as a better marker of mortality in chronic obstructive pulmonary disease (COPD) patients. The relationship among the IC/TLC ratio to lower extremity skeletal muscle function remains unknown.MethodsThirty-five men with moderate to severe COPD were divided into those with IC/TLC≤25% (n=16) and >25% (n=19). The subjects were tested for thigh muscle mass volume (MMT), maximal strength, power output of the lower extremities, and physical activity.ResultsTotal MMT in the IC/TLC<25% group was significantly lower (413.91±89.42cm3) (p<0.001) than in the IC/TLC>25% group (575.20±11.76cm3). In the IC/TLC≤25% group, maximal strength of the lower extremities and muscle peak power output of the lower extremities were 36–56% lower (p<0.01) than among the patients in the IC/TLC>25% group.ConclusionIC/TLC≤25% is associated with reduced maximal strength and peak power output of the lower extremities. IC/TLC≤25% may have an important clinical relevance as an index to determine peripheral muscle dysfunction

    Fabrication and microstructure of self-supporting thin ceramic electrolytes prepared by laser machining

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    Self-supporting thin Yttria Stabilized Zirconia (YSZ) ceramics electrolytes have been prepared by laser machining. They are carved from a sintered YSZ plate to shape a 20 µm thick and 8 mm in diameter central region, surrounded by an unprocessed 150 µm thick supporting zone. Scanning Electron Microscopy (SEM) and Electron BackScattering Diffraction (EBSD) studies confirmed that the strains produced by the laser processing are small and limited to only one or two layers of YSZ grains (~5 µm). SEM and Transmission Electron Microscopy (TEM) have been also used to characterize the surface of the membrane. It is corrugated and coated with YSZ nanoparticles as a result of the laser plasma deposition. Electrochemical characterization by Impedance Spectroscopy (EIS) showed that this surface morphology improves the electrical performance of the membrane slightly but clearly, reducing the cathode polarization resistance by about 5% in the 650-850 ºC range.This study was funded by the MAT2012-30763 project, which is financed by the Spanish Government (Ministerio de Economía y Competitividad) and the Feder program of the European Union.Peer Reviewe

    Empirical approach to the analysis of university student absenteeism. Proposal of a questionnaire for students to evaluate the possible causes

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    Works on student absenteeism in the universities have not been preferential for the authors in the field of educational research. Usually, what has been made is an approach to the available absenteeism data as an intervening variable or as a variable characteristic of the educational process, but not as a dependent variable in the strict sense of the term. In this work, we intend to make an empirical approach to the possible reasons of student absenteeism. There is a double point of view: the students" and the professors"; the reasons that justify it according to its protagonists are studied. This paper focuses on the six university degrees taught at the School of Economy and Business of the University of Barcelona (Facultat d"Economia i Empresa de la Universitat de Barcelona). An"ad-hoc" questionnaire has been prepared and the opinions of 1,162 undergraduates have been analyzed. The reasons given by each population differ in hierarchy and motivations

    Efectos de realizar actividad física en la función muscular en EPOC

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    The purpose of this study was to examine the effects of a 12-month physical activity (PA) programme consisting in walking on muscle function in patients with COPD (Chronic Obstructive Pulmonary Disease). Forty-four men (70.3 ± 6.7 years old) diagnosed with moderate-severe COPD were recruited. The intervention group (PAG) completed a physical activity programme and the control group (COG) followed their standard treatment. Upper-and lower-limb maximum strength (1RM), lower-limb muscle power (50% and 70% 1RM) and physical activity were measured before and after 12 months. After 12 months, lower-limb maximum strength increased by 8% in the PAG (P<0.01), while it did not change in the COG. Lower-limb muscle power at 50% 1RM increased by 12% in the PAG, while it decreased by 9% in the COG (P<0.05). A physical activity programme increased muscle strength and preserved muscle power of the lower limb. © 2021, Universidad Autonoma de Madrid y CV Ciencias del Deporte. All rights reserved

    Breast cancer PAM50 signature: Correlation and concordance between RNA-Seq and digital multiplexed gene expression technologies in a triple negative breast cancer series

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    Background: Full RNA-Seq is a fundamental research tool for whole transcriptome analysis. However, it is too costly and time consuming to be used in routine clinical practice. We evaluated the transcript quantification agreement between RNA-Seq and a digital multiplexed gene expression platform, and the subtype call after running the PAM50 assay in a series of breast cancer patients classified as triple negative by IHC/FISH. The goal of this study is to analyze the concordance between both expression platforms overall, and for calling PAM50 triple negative breast cancer intrinsic subtypes in particular. Results: The analyses were performed in paraffin-embedded tissues from 96 patients recruited in a multicenter, prospective, non-randomized neoadjuvant triple negative breast cancer trial (NCT01560663). Pre-treatment core biopsies were obtained following clinical practice guidelines and conserved as FFPE for further RNA extraction. PAM50 was performed on both digital multiplexed gene expression and RNA-Seq platforms. Subtype assignment was based on the nearest centroid classification following this procedure for both platforms and it was concordant on 96% of the cases (N = 96). In four cases, digital multiplexed gene expression analysis and RNA-Seq were discordant. The Spearman correlation to each of the centroids and the risk of recurrence were above 0.89 in both platforms while the agreement on Proliferation Score reached up to 0.97. In addition, 82% of the individual PAM50 genes showed a correlation coefficient > 0.80. Conclusions: In our analysis, the subtype calling in most of the samples was concordant in both platforms and the potential discordances had reduced clinical implications in terms of prognosis. If speed and cost are the main driving forces then the preferred technique is the digital multiplexed platform, while if whole genome patterns and subtype are the driving forces, then RNA-Seq is the preferred method
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