Repercusiones posturales con los estiramientos en flexión de tronco y las pruebas de distancia dedos-planta y distancia dedos-suelo

La postura corporal no es un concepto estrictamente estático, siendo preciso analizar aquellos movimientos y ejercicios que se realizan con gran frecuencia en la actividad física y que repercuten de forma directa en diversas estructuras del aparato locomotor, fundamentalmente en el raquis. En el presente artículo de revisión se ofrece un estudio de dos ejercicios ampliamente utilizados en el ámbito clínico y de la actividad física, como son los estiramiento en flexión de tronco y los tests de flexibilidad de Distancia Dedos-Planta y Distancia Dedos-Suelo, que frecuentemente se efectúan con dudosa corrección. Podremos comprobar cómo su ejecución incorrecta influye negativamente sobre la estabilidad del raquis y estableceremos estrategias para su realización de forma correcta

Use of Tyre-Derived Aggregate as Backfill Material for Wave Barriers to Mitigate Railway-Induced Ground Vibrations

[Abstract] The use of piles as barriers to mitigate vibrations from rail traffic has been increasing in theoretical and practical engineering during the last years. Tyre-derived aggregate (TDA) is a recycled material with some interesting applications in civil engineering, including those related to railway engineering. As a novelty, this paper combines the concept of pile wave barriers and TDA material and investigates the mitigation effect of pile barriers made of TDA on the vibrations transmitted by rail traffic. This solution has a dual purpose: the reduction of railway vibrations and the recycling of a highly polluting material. The mitigation potential of this material when used as backfill for piles is analysed using a numerical scheme based on a 3D finite-difference numerical model formulated in the space/time domain, which is also experimentally validated in this paper in a real case without pile barriers. The numerical results show insertion loss (IL) values of up to 11 dB for a depth closed to the wavelength of Rayleigh wave. Finally, this solution is compared with more common backfills, such as concrete and steel tubular piles, showing that the TDA pile is a less effective measure although from an environmental and engineering point of view it is a very competitive solution

A High-Efficiency Isolated Wide Voltage Range DC-DC Converter Using WBG Devices

The recent release of the standard USB-PD 3.1 speci es variable output voltages from 5 V to 48 V featuring a step forward towards a universal adaptor but rising new challenges for the converter topologies used up to now. In such applications, a rst AC-DC stage is followed by a DC-DC stage. In this paper, emerging WBG technologies are applied to the asymmetrical half-bridge yback topology, demonstrating the potential of such combination as a wide voltage range DC-DC stage. Its suitability for high-density and high-ef ciency USB-PD Extended Power Range (EPR) and battery charger applications is discussed. The impact of different switching technologies, silicon and wide band gap, is analyzed. A general method to dimension the converter is presented and an iterative process is used to evaluate the theoretical ef ciency under different conditions and switching devices. Finally, the advantages of the presented converter using Gallium Nitride (GaN) devices are demonstrated in a 240 W DC-DC prototype. It achieves a full load ef ciency of 98%, and it is able to deliver an output voltage from 5 V to 48 V with input voltage range from 120 V to 420 V, as well an outstanding power density of 112 W/inch3 uncased.Infineon Technologies AG through the Spanish Regional Project P20_00265 BRNM-680-UGR20Spanish Ministry of Science MCIN/AEI PID2020-117344RB-I0

Histoplasma capsulatum in the bone marrow of an HIV-infected patient

A 41-year-old man was admitted to the emergency department with a 1-month history of weight loss, intermittent fever, and malaise. Generalized pallor, mild dehydration, and a temperature of 37.5 �C were found on physical examination. Initial blood workup revealed pancytopenia, elevated lactate dehydrogenase, and hypoalbuminemia. A fourth-generation HIV ELISA test was positive. His HIV-1 RNA viral load was 13 800 copies/ml and the CD4+ T-cell count was 3 cells/mm3 . Urine, blood, and cerebrospinal fluid cultures were without microbiological isolatio

Early Serpukhovian conodonts from the Guadiato Area (Córdoba, Spain)

The conodont assemblages of three stratigraphic sections from lower Serpukhovian rocks of the Guadiato Area (southwestern Spain) are composed of fifteen taxa, included in nine genera. Many of them are identified in open nomenclature due to the poor preservation of the specimens, of which most of them are fragmented, the presence of juvenile specimens, and the current controversy in the recognition of some multielement apparatuses. Generally, the faunas are not highly diversified and there is a low abundance of specimens in the horizons that yield conodonts. The assemblages include: Cavusgnathus navicula, Cavusgnathus cf. navicula, Gnathodus girtyi, of which two subspecies were identified, Gnathodus girtyi girtyi and Gnathodus girtyi meischneri, Hindeodontoides? sp., Hindeodus cristula, Idioprioniodus healdi, Idioprioniodus spp., Kladognathus macrodentata?, Kladognathus tenuis-complectens, Lochriea? sp., Mestognathus bipluti, Synclydognathus geminus, Synclydognathus spp. and many unidentifiable fragments

Resonant Hybrid Flyback, a New Topology for High Density Power Adaptors

In this article, an innovative power adaptor based on the asymmetrical pulse width modulation (PWM) flyback topology will be presented. Its benefits compared to other state-of-the-art topologies, such as the active clamp flyback, are analyzed in detail. It will also describe the control methods to achieve high efficiency and power density using zero-voltage switching (ZVS) and zero-current switching (ZCS) techniques over the full range of the input voltage and the output load, providing comprehensive guidelines for the practical design. Finally, we demonstrate the convenience of the proposed design methods with a 65 W adaptor prototype achieving a peak efficiency of close to 95% and a minimum efficiency of 93.4% at full load over the range of the input voltage, as well as a world-class power density of 22 W/inch3 cased.This research is financed by Infineon Tecnologias AG

Motivation and Perceived Learning of Secondary Education History Students. Analysis of a Programme on Initial Teacher Training

This paper presents the results of research on the initial teacher training in Spain. The aim is to verify whether the development of a training program for teachers based on methodological and epistemological aspects has a positive repercussion on the learning of secondary school pupils. We evaluated to what degree this training was reflected in secondary education pupils (n = 467, Mage = 14.74, SD = 1.97) taught by the participating trainee teachers during their period of teaching practice. A pretest and a postest were employed to obtain data on the methodology and the motivation and perceived learning on the part of the pupils. A confirmatory factor analysis was carried out to verify the validity and internal consistency of the tools and, later, the longitudinal invariance in each of the dimensions analyzed. The results confirm the internal consistency and validity of the tools employed and the improvement in the pupils' evaluation regarding methodology, motivation, and learningThis article has been possible thanks to the research project funded by Ministry of Science, University and Innovation, co-funded by FEDER funding Conceptos Metodológicos y Métodos Activos de Aprendizaje para la Mejora de las Competencias Docentes del Profesorado (PGC2018-094491-B-C33) (MCI/AEI/FEDER, UE), and project Competencias Docentes y Métodos Activos de Aprendizaje. Una Investigación Evaluativa con el Profesorado en Formación de Ciencias Sociales (20638/JLI/18), funded by Seneca Foundation [35500/20638/JLI/18]; Ministry of Science, Innovation and Universities [11550/PGC2018-094491-B-C33] (MCI/AEI/FEDER, UE)S

An evaluation of an intervention programme in teacher training for geography and history: A reliability and validity analysis

Producción CientíficaWe evaluated a teacher training intervention programme aimed at improving the teaching and learning process relating to history in the secondary classroom. This was carried out via the implementation of several teaching units during the period of teaching practice of trainee teachers specialising in geography and history. The design of the teaching units was based on historical thinking competencies and on the introduction of active learning strategies. The programme was evaluated via a quasi-experimental A-B type methodological approach employing a pretest and a post-test. Both tools were designed on the basis of four dimensions (methodology, motivation, satisfaction and perception). The content of the tools was validated using the interjudge process via a discussion group in the first round and with a Likert scale questionnaire (1–4) with seven experts in the second round. The reliability of the tools has been estimated via three indices (Cronbach’s alpha, composite reliability and omega), and the validity of the construct via an exploratory (EFA) and confirmatory factor analysis (CFA) with the structural equation model. The results regarding reliability and validity have been adequate. Furthermore, the descriptive results show an improvement in all of the dimensions following the implementation of the teaching units, particularly with regard to group work, the use of digital resources and work with primary sources.Ministerio de Ciencia, Innovación y Universidades - Fondo Europeo de Desarrollo Regional (project PGC2018-094491-B-C33)Fundación Séneca-Agencia de Ciencia y Tecnología de la Región de Murcia (project 20638/JLI/18

Numerical Simulation of Bitumen Emulsion-Stabilised Base Course Mixtures With C&D Waste Aggregates Considering Nonlinear Elastic Behaviour

[Abstract:] This study presents the numerical modelling of a load-volume road pavement section with bitumen emulsion-stabilised base courses. The base courses used natural and construction and demolition aggregates. A 3D finite difference model was used to determine the peak responses of the pavement sections when subjected to loads. Three nonlinear models were adopted in the two base courses. The response predictions of the three models were similar. Both the resilient and permanent behaviours of these materials were modelled. An analysis was conducted on the rutting resistance of the base course materials. Both base courses were suitable for use in low-volume roads. The base course made with construction and demolition aggregates was more resistant to rutting.Ministerio de Economía y Competitividad; BIA2016-80317-

Advanced control methods for Asymmetrical Half-bridge Flyback

—In this article, a power converter based on an asymmetrical half-bridge flyback topology is analyzed and optimized for small form factor and fast-charging power adaptors. Two resonant control methods, taking advantage of the forward and flyback characteristics of the converter, as well as the benefits of each of them depending of the operation point are discussed. The analysis is nourished with the equivalent circuits in each phase of operation and the equations that define them. Particularly innovative is the proposed zero voltage resonant valley switching control method for the mentioned converter; in this case, it is operated similarly to a flyback converter, allowing safe output voltage ramp up, which is one of the challenges that has limited the usage of this topology up to now. The manuscript also describes how to achieve high efficiency and power density using zero-voltage switching and zero-current switching techniques over the full range of the input voltage and the output load. Finally, the advantages of the proposed control methods are demonstrated in a 65-W adaptor prototype achieving a peak efficiency over 94.6% and an efficiency of 93.8% @ Vac ≥ 100 V at full load over the range of the input voltage, as well as a world-class power density of 35 W/in3 uncasedhis work was supported by Infineon Technologies AG by Contract OTRI 3770-05 and Contract OTRI 3770-0