Validation of the cognitive structure of the test of signs by structural equation modeling

El objetivo de este trabajo es realizar un estudio de validación de los procesos cognitivos implicados en la resolución de ítems de un test de operaciones aritméticas básicas entre números enteros. La validación de la estructura cognitiva propuesta para la tarea se lleva a cabo mediante modelos de ecuaciones estructurales y triangulación. Los resultados muestran relaciones de subordinación fuertes y positivas entre los ítems en algunas de las rutas, apoyando solo parcialmente la estructura propuesta. Sin embargo, la triangulación aporta una mayor evidencia de validez.The present work is aimed to carry out a validation study of the cognitive operations required for the correct solution of items of a math test which includes basic arithmetic operations between integer numbers. The validation of the hypothesized cognitive structure is made by means of structural equation modeling and triangulation methods. Results show strong and positive cognitive subordination relationships between some items but the structural equation model fit only provides a partial support for the proposed structure. However, the triangulation procedure provides further evidence of validity.Este trabajo está financiado por el proyecto de la DGICYT (ref. SEJ2004-05872

Detection of Q-matrix misspecification using two criteria for validation of cognitive structures under the Least Squares Distance Model

Cognitive Diagnostic Models (CDMs) aim to provide information about the degree to which individuals have mastered specific attributes that underlie the success of these individuals on test items. The Q-matrix is a key element in the application of CDMs, because contains links item-attributes representing the cognitive structure proposed for solve the test. Using a simulation study we investigated the performance of two model-fit statistics (MAD and LSD) to detect misspecifications in the Q-matrix within the least squares distance modeling framework. The manipulated test design factors included the number of respondents (300, 500, 1000), attributes (1, 2, 3, 4), and type of model (conjunctive vs disjunctive). We investigated MAD and LSD behavior under correct Q-matrix specification, with Qmisspecifications and in a real data application. The results shows that the two model-fit indexes were sensitive to Q-misspecifications, consequently, cut points were proposed to use in applied context.Detección de errores de especificación en la matriz Q utilizando dos criterios de validación de estructuras cognitivas con el Modelo de las Distancias Mínimo Cuadráticas (LSDM). Los Modelos de Diagnóstico Cognitivo (MDC) tienen por objeto proporcionar información sobre el grado en que los individuos dominan atributos específicos para resolver correctamente los items de un test. La matriz Q es un elemento clave en la aplicación de los MDC porque contiene vínculos entre items y atributos que representan la estructura cognitiva propuesta para resolver la prueba. Por medio de un estudio de simulación, se determinó el rendimiento de dos estadísticos de ajuste (MAD y LSD) para detectar errores de especificación en la matriz Q dentro del marco del modelo de la distancia mínimo cuadrática. Los factores manipulados en el diseño del test incluyen: número de encuestados (300, 500, 1000), número de atributos (1, 2, 3, 4), y el tipo de modelo (conjuntivo vs. disyuntivo). Se investigó el comportamiento de los valores MAD y LSD bajo una correcta especificación de Q, con errores de especificación en Q y en una aplicación de datos reales. Los resultados muestran que los dos índices son sensibles a los errores de especificación de Q, por este motivo se proponen puntos de corte para usar en aplicaciones del modelo

Early prediction of undergraduate Student's academic performance in completely online learning: A five-year study

This decade, e-learning systems provide more interactivity to instructors and students than traditional systems and make possible a completely online (CO) education. However, instructors could not warn if a CO student is engaged or not in the course, and they could not predict his or her academic performance in courses. This work provides a collection of models (exploratory factor analysis, multiple linear regressions, cluster analysis, and correlation) to early predict the academic performance of students. These models are constructed using Moodle interaction data, characteristics, and grades of 802 undergraduate students from a CO university. The models result indicated that the major contribution to the prediction of the academic student performance is made by four factors: Access, Questionnaire, Task, and Age. Access factor is composed by variables related to accesses of students in Moodle, including visits to forums and glossaries. Questionnaire factor summarizes variables related to visits and attempts in questionnaires. Task factor is composed of variables related to consulted and submitted tasks. The Age factor contains the student age. Also, it is remarkable that Age was identified as a negative predictor of the performance of students, indicating that the student performance is inversely proportional to age. In addition, cluster analysis found five groups and sustained that number of interactions with Moodle are closely related to performance of students.2020-2

Estudio sobre el comportamiento ético en las organizaciones: ¿por qué la ética se queda en las palabras?

This research focuses on the behavioral factors of professional practice that enable or hinders the implementation of ethical business models. The paper aims to measure the degree to which present the «proto-ethical competence», in 187 Spanish companies, by means of the evaluation of the attitude that make possible the professional achievement from models committed with the environment and the people. The present study shows that the set of competencies defined (responsibility, commitment, respect, consistency, effort and sincerity) behaves as a single block. The study also analyzed differences of ethical behavior among different groups according to variables such as gender, age, sector, hierarchical level and organizational size. Additionally, the paper provides a tool to measure reliably the presence of these skills in a business environment.En esta investigación se estudian los factores comportamentales de la práctica profesional que posibilitan o dificultan la implantación de modelos empresariales éticos. El trabajo pretende medir el grado en el que están presentes las «competencias proto-éticas», en 187 empresas españolas, mediante la evaluación de las actitudes que hacen posible la ejecución profesional desde modelos comprometidos con la persona y el entorno. En el presente estudio encontramos que el conjunto de competencias éticas que se ha definido (responsabilidad, compromiso, respeto, coherencia, esfuerzo y sinceridad) se comporta como un único bloque. También se analizan las diferencias del comportamiento ético entre diferentes colectivos en función de variables como: género, edad, sector, nivel jerárquico y tamaño de la organización. Adicionalmente, se aporta una herramienta capaz de medir con fiabilidad la presencia de estas competencias en los entornos profesionales

Sliding mode control of switching converters: general theory in an integrated solution

The application of the sliding-mode control theory to the regulation of dc-to-dc switching converters is reviewed. Subsequently, linear dynamical models are derived and compensating networks are designed. An analog integrated circuit illustrating the theory has been designed, implemented and applied to regulate a buck converter in continuous conduction mode. Experimental verifications are provided.Peer ReviewedPostprint (published version

Las redes sociales en la Educación Primaria: conocimiento y uso por parte de maestros participantes en un entorno formativo

In recent years, the use of social networks has grown to currently become important communication tools. In school education it is possible to take profits to the potential of social networks to work with students of different educational stages several curricular contents. At the same time, pupils can develop skills to use social networks properly. In the present study we asses­sed the degree of knowledge about social networks and the kind of use of a sample of Primary teachers. Furthermore, we  compare teachers’ perception of utility and their disposition to use social networks after a training process. The majority of the parti­cipants consider social networks as useful or very useful. Nevertheless they have dee­per knowledge of common social networks than of specific educational networks. Addi­tionally, they seem to be unconscious of the characteristics and possibilities of the later. After training, the teachers increased their perception of utility and their disposition to incorporate social networks to their educa­tional activities.En los últimos años, el uso de las redes sociales ha aumentado hasta convertirse actualmente en importantes herramientas de comunicación. En la educación escolar se pueden aprovechar las posibilidades de las redes sociales para trabajar contenidos curriculares con alumnos de diferentes etapas a la vez que se fomenta que estos desarrollen competencias para su correcto uso. En este estudio indagamos el grado de conocimiento y el uso que hacen de las redes sociales una muestra de docentes de Primaria. Además, comparamos su percepción de utilidad y de disposición a usarlas tras un breve proceso formativo. La mayoría de los participantes consideran útiles o muy útiles las redes sociales, pero conocen y usan en mayor medida redes generalistas que redes específicamente educativas, mostrando desconocimiento sobre las características y posibilidades de estas últimas. Tras la formación, aumenta la percepción sobre su utilidad y se muestra una alta disposición a la incorporación a las actividades docentes

Identification of oxidative stress related proteins as biomarkers for lung cancer and chronic obstructive pulmonary disease in bronchoalveolar lavage

Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) commonly coexist in smokers, and the presence of COPD increases the risk of developing LC. Cigarette smoke causes oxidative stress and an inflammatory response in lung cells, which in turn may be involved in COPD and lung cancer development. The aim of this study was to identify differential proteomic profiles related to oxidative stress response that were potentially involved in these two pathological entities. Protein content was assessed in the bronchoalveolar lavage (BAL) of 60 patients classified in four groups: COPD, COPD and LC, LC, and control (neither COPD nor LC). Proteins were separated into spots by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) and examined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/TOF). A total of 16 oxidative stress regulatory proteins were differentially expressed in BAL samples from LC and/or COPD patients as compared with the control group. A distinct proteomic reactive oxygen species (ROS) protein signature emerged that characterized lung cancer and COPD. In conclusion, our findings highlight the role of the oxidative stress response proteins in the pathogenic pathways of both diseases, and provide new candidate biomarkers and predictive tools for LC and COPD diagnosis. © 2013 by the authors; licensee MDPI, Basel, Switzerland.LPA is funded by Fondo de Investigación Sanitaria (PI081156) and Fondo de Investigación Sanitaria (PI1102688). MDP is funded by Fondo de Investigación Sanitaria (CD 09/00148). AN is funded by the Portuguese Ministry of Science, Technology and Superior Education—FCT (Fundação para a Ciência e para a Tecnologia: SFRH/BD/48341/2008). SMP is funded by Fondo de Investigación Sanitaria (CD 11/00153).Peer Reviewe

Intra-individual effects of food upon the pharmacokinetics of rifampicin and isoniazid

Background: Poor response to TB therapy might be attributable to subtherapeutic levels in drug-compliant patients. Pharmacokinetic parameters can be affected by comorbidities or the interaction of drugs with food. Objectives: This study aimed to determine the effect of food intake upon pharmacokinetics of rifampicin and isoniazid in a Peruvian population with TB. Methods: Rifampicin and isoniazid levels were analysed at 2, 4 and 6 h after drug intake in both fasting and non-fasting states using LC-MS methods. Results: Sixty patients participated in the study. The median rifampicin Cmax and AUC0–6 were higher during fasting than non-fasting: 7.02 versus 6.59 mg/L (P = 0.054) and 28.64 versus 24.31 mg·h/L (P = 0.002). There was a statistically significant delay overall of non-fasting Tmax compared with the fasting state Tmax (P = 0.005). In the multivariate analysis, besides the effect of fasting, Cmax for females was 20% higher than for males (P = 0.03). Concerning isoniazid, there were significant differences in the Cmax during non-fasting (median = 3.51 mg/L) compared with fasting (4.54 mg/L). The isoniazid dose received had an effect upon the isoniazid levels (1.26, P = 0.038). In the multivariate analysis, isoniazid exposure during fasting was found to be 14% higher than during non-fasting (CI = 1.02–1.28, P < 0.001). Neither radiological extent of the disease nor consumption of food with drug intake nor pharmacokinetics of rifampicin or isoniazid was associated with a poorer treatment outcome. Conclusions: Rifampicin in particular and isoniazid pharmacokinetics were significantly affected by the intake of the drug with food between and within individuals

Generation and characterization of the human iPSC line PBMC1-iPS4F1 from adult peripheral blood mononuclear cells

AbstractHere we describe the generation and characterization of the human induced pluripotent stem cell (iPSC) line PBMC1-iPS4F1 from peripheral blood mononuclear cells from a healthy female with Spanish background. We used heat sensitive, non-integrative Sendai viruses containing the reprogramming factors Oct3/4, Sox2, Klf4 and c-Myc, whose expression was silenced in the established iPSC line. Characterization of the PBMC1-iPS4F1 cell line included analysis of typical pluripotency-associated factors at mRNA and protein level, alkaline phosphatase enzymatic activity, and in vivo and in vitro differentiation studies

COVID-19 in hospitalized HIV-positive and HIV-negative patients: A matched study

Objectives: We compared the characteristics and clinical outcomes of hospitalized individuals with COVID-19 with [people with HIV (PWH)] and without (non-PWH) HIV co-infection in Spain during the first wave of the pandemic. Methods: This was a retrospective matched cohort study. People with HIV were identified by reviewing clinical records and laboratory registries of 10 922 patients in active-follow-up within the Spanish HIV Research Network (CoRIS) up to 30 June 2020. Each hospitalized PWH was matched with five non-PWH of the same age and sex randomly selected from COVID-19@Spain, a multicentre cohort of 4035 patients hospitalized with confirmed COVID-19. The main outcome was all-cause in-hospital mortality. Results: Forty-five PWH with PCR-confirmed COVID-19 were identified in CoRIS, 21 of whom were hospitalized. A total of 105 age/sex-matched controls were selected from the COVID-19@Spain cohort. The median age in both groups was 53 (Q1-Q3, 46-56) years, and 90.5% were men. In PWH, 19.1% were injecting drug users, 95.2% were on antiretroviral therapy, 94.4% had HIV-RNA < 50 copies/mL, and the median (Q1-Q3) CD4 count was 595 (349-798) cells/μL. No statistically significant differences were found between PWH and non-PWH in number of comorbidities, presenting signs and symptoms, laboratory parameters, radiology findings and severity scores on admission. Corticosteroids were administered to 33.3% and 27.4% of PWH and non-PWH, respectively (P = 0.580). Deaths during admission were documented in two (9.5%) PWH and 12 (11.4%) non-PWH (P = 0.800). Conclusions: Our findings suggest that well-controlled HIV infection does not modify the clinical presentation or worsen clinical outcomes of COVID-19 hospitalization.This work was supported by the Instituto de Salud Carlos III (ISCII) (grant no. COV20/00108) and the Spanish AIDS Research Network (RD16/0025), which is included in the Spanish I+D+I Plan and is co- funded by ISCIII- Subdirección General de Evaluación and European Funding for Regional Development (FEDER)S