El pensamiento estadístico en la planificación de lecciones de estadística por profesores de secundaria

En este artículo se analiza el discurso de cinco profesores durante la planificación de una lección sobre gráficas y medidas de tendencia central como parte de tres actividades profesionales (planificación, enseñanza y análisis de lecciones de clase) que llevan a cabo en un proyecto de desarrollo profesional enfocado a la enseñanza-aprendizaje de la estadística. En este artículo sólo se estudia la fase de planificación con el objetivo de identificar las dificultades y posibilidades que los profesores poseen para diseñar estrategias de enseñanza; también, se estudia en qué medida se reflejan los elementos de un pensamiento estadístico en la lección planificada

Metallo-Dielectric Colloidal Films as SERS Substrate

Along this chapter, we probe that the discrete dipole approximation models fairly well the optical response of periodic systems. Herein, we use it to model the reflectance and transmittance, at normal incidence, of colloidal films made of SiO2 spheres. As the thickness increases from 1 to 12 layers, the photonic band gap shifts to the blue tending to the value corresponding to a 3D opal, 442 nm. A film with more than eight layers resembles the bulk properties of a 3D opal. Our results are compared to a real sample. Besides, we show that taking advantage of the wide and asymmetrical absorbance spectrum of an opal with Au NPs is possible to identify the contribution of each component in the overall spectrum, through a deconvolution analysis. Finally, we present the electric field intensity as the content of metal NP increases in a monolayer. We consider NPs one order of magnitude smaller than the silica spheres, and then, 6, 9, and 17 NPs are hosted in the void. Similar average electric field intensities, about 11 times the incident intensity, are obtained with Au and Ag NPs. But, the spots with these intensities cover a bigger area with Ag NPs than with Au NPs

The Conformational Stability and Biophysical Properties of the Eukaryotic Thioredoxins of Pisum Sativum Are Not Family-Conserved

Thioredoxins (TRXs) are ubiquitous proteins involved in redox processes. About forty genes encode TRX or TRX-related proteins in plants, grouped in different families according to their subcellular localization. For instance, the h-type TRXs are located in cytoplasm or mitochondria, whereas f-type TRXs have a plastidial origin, although both types of proteins have an eukaryotic origin as opposed to other TRXs. Herein, we study the conformational and the biophysical features of TRXh1, TRXh2 and TRXf from Pisum sativum. The modelled structures of the three proteins show the well-known TRX fold. While sharing similar pH-denaturations features, the chemical and thermal stabilities are different, being PsTRXh1 (Pisum sativum thioredoxin h1) the most stable isoform; moreover, the three proteins follow a three-state denaturation model, during the chemical-denaturations. These differences in the thermal- and chemical-denaturations result from changes, in a broad sense, of the several ASAs (accessible surface areas) of the proteins. Thus, although a strong relationship can be found between the primary amino acid sequence and the structure among TRXs, that between the residue sequence and the conformational stability and biophysical properties is not. We discuss how these differences in the biophysical properties of TRXs determine their unique functions in pea, and we show how residues involved in the biophysical features described (pH-titrations, dimerizations and chemical-denaturations) belong to regions involved in interaction with other proteins. Our results suggest that the sequence demands of protein-protein function are relatively rigid, with different protein-binding pockets (some in common) for each of the three proteins, but the demands of structure and conformational stability per se (as long as there is a maintained core), are less so

Platelet-derived extracellular vesicles promote tenogenic differentiation of stem cells on bioengineered living fibers

Tendon mimetic scaffolds that recreate the tendon hierarchical structure and niche have increasing potential to fully restore tendon functionality. However, most scaffolds lack biofunctionality to boost the tenogenic differentiation of stem cells. In this study, we assessed the role of platelet-derived extracellular vesicles (EVs) in stem cellsâ tenogenic commitment using a 3D bioengineered in vitro tendon model. First, we relied on fibrous scaffolds coated with collagen hydrogels encapsulating human adipose-derived stem cells (hASCs) to bioengineer our composite living fibers. We found that the hASCs in our fibers showed high elongation and cytoskeleton anisotropic organization, typical of tenocytes. Moreover, acting as biological cues, platelet-derived EVs boosted the hASCsâ tenogenic commitment, prevented phenotypic drift, enhanced the deposition of the tendon-like extracellular matrix, and induced lower collagen matrix contraction. In conclusion, our living fibers provided an in vitro system for tendon tissue engineering, allowing us to study not only the tendon microenvironment but also the influence of biochemical cues on stem cell behavior. More importantly, we showed that platelet-derived EVs are a promising biochemical tool for tissue engineering and regenerative medicine applications that are worthy of further exploration, as paracrine signaling might potentiate tendon repair and regeneration

Therapeutic effects of platelet-derived extracellular vesicles in a bioengineered tendon disease model

Tendon injuries represent over 30–50% of musculoskeletal disorders worldwide, yet the available therapies do not provide complete tendon repair/regeneration and full functionality restor-ing. Extracellular vesicles (EVs), membrane-enclosed nanoparticles, have emerged as the next breakthrough in tissue engineering and regenerative medicine to promote endogenous tissue regen-eration. Here, we developed a 3D human in vitro model mimicking the signature of pathological tendon and used it to evaluate the influence that different platelet-derived EVs might have in tendon tissue repair mechanisms. For this, different EV populations isolated from platelets, small EVs (sEVs) and medium EVs (mEVs), were added to the culture media of human tendon-derived cells (hTDCs) cultured on isotropic nanofibrous scaffolds. The platelet-derived EVs increased the expression of tenogenic markers, promoted a healthy extracellular matrix (ECM) remodeling, and the synthesis of anti-inflammatory mediators. These findings suggest that platelet EVs provided relevant biochemical cues that potentiated a recovery of hTDCs phenotype from a diseased to a healthy state. Thus, this study opens new perspectives for the translation of platelet-derived EVs as therapeutics.This research was funded by the ERC CoG MagTendon grant agreement 772817; EC Twinning project Achilles 810850; Fundacao para a Ciencia e a Tecnologia (FCT) for PhD grant PD/59/2013 and PD/BD/135255/2017, individual contracts CEECIND/01375/2017 (M.G.-F.) and 2020.03410.CEECIND (R.M.A.D), and project PTDC/NAN-MAT/30595/2017

Comparison of two-step transient evoked otoacoustic emissions (TEOAE) and automated auditory brainstem response (AABR) for universal newborn hearing screening programs

Producción CientíficaBoth transitory auditory otoemissions (TEOAE) and automated auditory brainstem responses (AABR) are considered adequate methods for universal hearing screening. The goal of this study was to compare the results obtained with each device, applying the same screening procedure. MATERIALS AND METHODS:From 2001 to 2003, all the newborns in our health area (2454 infants) were evaluated with TEOAE (ILO92, otodynamics) and all those born from 2004 to 2006 (3117) were evaluated with AABR (AccuScreen, Fischer-Zoth). The population studied included all well newborns and those admitted to neonatal intensive care units (NICU). The first screening was normally undertaken with well babies during the first 48h of life, before hospital discharge. Infants referred from this first step underwent a second screening after hospital discharge, before they were a month old. RESULTS:The results from each study group were compared and analyzed for significant differences. TEOAE screening yielded 10.2% fail results from the first screening step; AABR gave 2.6%. In the second screening step, 2% of the newborns screened with TEOAE were referred, whereas 0.32% of those screened with AABR were referred. These differences are statistically significant. CONCLUSIONS:Although AABR screening tests involve a slightly higher cost in time and money than TEOAE, the results obtained compensate this difference. AABR gives fewer false positives and a lower referral rate; the percent of infants lost during follow-up is consequently smaller. Therefore, in our environment, universal newborn auditory screening with AABR is more effective than that with TEOAE

Deuda viva municipal en un contexto de crisis económica: análisis de los factores determinantes y de las formas de gestión

ResumenLa especial situación de crisis económica, junto con las restricciones al endeudamiento impuestas a los ayuntamientos y el control del déficit público, han reducido los recursos de las administraciones locales. En este contexto, los gestores encuentran en la creación de entes instrumentales una herramienta que permite al ayuntamiento no computar en su presupuesto determinados niveles de deuda. El objetivo del presente trabajo es determinar si la cooperación intermunicipal, la colaboración público-privada y la descentralización, junto con los aspectos políticos y financieros de la entidad, son factores que condicionan que el ayuntamiento presente un determinado nivel de deuda en período de crisis económica. Para ello, utilizando diferentes bases de datos, se estudia sobre una muestra de 1.238 municipios, para el período 2008-2011, cuáles de estos factores influyen sobre la deuda de los municipios españoles. Los resultados muestran, tras la aplicación de un modelo de regresión agrupada, que las variables financieras influyen sobre el nivel de deuda del municipio, así como la tasa de inmigración y la presencia o no de fragmentación política en el gobierno local. Igualmente, se ha obtenido evidencia de que tanto los ayuntamientos con mayor cooperación intermunicipal como aquellos con un mayor grado de descentralización presentan un mayor nivel de deuda.AbstractAs a result of the current economic crisis, with the consequent borrowing constraints imposed on municipalities and curbs on public deficit, the resources of local governments have been severely reduced. In this context, the creation of devolved organizations provides municipalities with a means of eliminating certain forms of debt from their budget items. The aim of this study is to determine whether inter-municipal cooperation, public-private collaboration and decentralization, together with the political and financial characteristics of the local authority in question, are factors constraining it to present a particular level of debt in times of economic crisis. To achieve these goals, various databases were used to study a sample of 1,238 local authorities for the period 2008-2011, to determine which of these factors influence municipal debt in Spain. Application of a pooled regression model showed that financial variables are factors that influence the level of municipal debt, as does the political orientation of the governing local party. We also found that local councils presenting higher levels of inter-municipal cooperation and those with a higher degree of decentralization have higher levels of debt

Nutritional problems perceived by pediatricians in Spanish children younger than 3 years

Introducción: Los padres son los principales responsables de la educación nutricional de sus hijos y es labor del pediatra orientar y resolver problemas al respecto. En este estudio se pretende conocer la relevancia de las cuestiones nutricionales en la consulta del pediatra y los principales problemas nutricionales percibidos en los menores de 3 años. Métodos: Estudio descriptivo, transversal en dos fases. La primera consistió en entrevistas y grupos de discusión con 30 pediatras seleccionados aleatoriamente en Madrid y Barcelona. Los resultados se utilizaron para diseñar el cuestionario online (76 preguntas relacionadas con la nutrición en niños de 0-3 años) de la siguiente fase, en la que participaron pediatras seleccionados de forma aleatoria y representativa del territorio nacional. Resultados: De 258 pediatras seleccionados, completaron el cuestionario 151, que atendían a una media de 588 pacientes/mes. Los principales problemas nutricionales percibidos hasta los 12 meses fueron las deficiencias de hierro y vitaminas y la escasa ganancia de peso, y posteriormente la ingesta excesiva de carbohidratos y lípidos y el sobrepeso. Los padres fueron considerados los actores principales en la salud nutricional de sus hijos, pero su preocupación por esta cuestión se reduce significativamente (p < 0,0001) con la edad del niño. Los aspectos considerados más importantes para obtener unos buenos hábitos alimentarios fueron la alimentación adaptada a las necesidades del niño y respetar el tiempo de sueño. El porcentaje de pacientes que recibe recomendaciones de hábitos nutricionales varió del 88% (0-6 meses) al 61% (24-36 meses). Conclusiones: A pesar de considerar la salud nutricional importante, la intervención educativa del pediatra al respecto no es óptima. Los problemas nutricionales percibidos fueron distintos según la edadIntroduction: Parents are most responsible for nutritional education of children, and pediatritians must advise and help them with their doubts. The purpose of this study was to know the relevance of nutritional topics in daily practice and the main nutritional problems perceived by pediatritians in children under 3 years of age. Methods: Descriptive, cross-sectional study performed in 2 stages. First stage consisted on discussion meetings with 30 random-selected pediatritians from Madrid and Barcelona. Results were used to design the on-line questionnaire of the second stage (76 questions related to nutrition in children under 3 years). A random and representative sample of Spanish pediatritians was selected for this stage. Results: One hundred and fifty one pediatritians, among 258 sampled, completed the questionnaire. They referred to see a mean of 588 patients/month. The main perceived nutritional problems in the first year of life were iron and vitamin deficiencies and poor weight gain. In the next months, excess in carbohydrates and lipid intake and overweight were the main problems perceived. Parents were considered the main actors regarding their children’s nutritional health, but their concern in these questions significantly reduced with children’s age (p < 0,0001). Factors considered to have the greatest relevance in the acquisition of good nutritional habits were to provide a diet adjusted for children’s requirements and to observe the appropriate sleeping hours. The proportion of children who receive nutritional counseling varied from 88% (0-6 months) to 61% (24-36 months). Conclusions: Despite of the relevance given by pediatritians, educational intervention regarding nutritional health is not ideal. Nutritional problems perceived by pediatritians varied with children’s ageEste estudio ha sido financiado por Almiron/Danone Baby Nutrition