Trunk and lower limb muscle activation in linear, circular and spin back kicks

As any martial art, taekwondo can be classified as a specialty that requires high technical skills, such as a fine motor control both in static and dynamic conditions. Practitioners predominantly use kicks with high amplitude in both combat and technique (poomse) modalities. The aim of this study was the knowledge about trunk and lower limb muscle activation according to the type of kick (circular, linear and spin back kick) in the taekwondo technique modality. Twelve healthy and elite male taekwondo athletes voluntarily participated in this study. Surface electromyography (EMG) during maximal isometric voluntary contractions (MVC) and execution of the kicks was bilaterally recorded from rectus abdominis (RA), external and internal oblique (EO and IO), erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius lateralis (GL), in the static phase of the three kicks

Hypogammaglobulinemia in BLT Humanized Mice – An Animal Model of Primary Antibody Deficiency

Primary antibody deficiencies present clinically as reduced or absent plasma antibodies without another identified disorder that could explain the low immunoglobulin levels. Bone marrow-liver-thymus (BLT) humanized mice also exhibit primary antibody deficiency or hypogammaglobulinemia. Comprehensive characterization of B cell development and differentiation in BLT mice revealed other key parallels with primary immunodeficiency patients. We found that B cell ontogeny was normal in the bone marrow of BLT mice but observed an absence of switched memory B cells in the periphery. PC-KLH immunizations led to the presence of switched memory B cells in immunized BLT mice although plasma cells producing PCor KLH- specific IgG were not detected in tissues. Overall, we have identified the following parallels between the humoral immune systems of primary antibody deficiency patients and those in BLT mice that make this in vivo model a robust and translational experimental platform for gaining a greater understanding of this heterogeneous array of humoral immunodeficiency disorders in humans: (i) hypogammaglobulinemia; (ii) normal B cell ontogeny in bone marrow; and (iii) poor antigen-specific IgG response to immunization. Furthermore, the development of strategies to overcome these humoral immune aberrations in BLT mice may in turn provide insights into the pathogenesis of some primary antibody deficiency patients which could lead to novel clinical interventions for improved humoral immune function

Web-based OERs in Computer Networks

Learning and teaching processes are continually changing. Therefore, design of learning technologies has gained interest in educators and educational institutions from secondary school to higher education. This paper describes the successfully use in education of social learning technologies and virtual laboratories designed by the authors, as well as videos developed by the students. These tools, combined with other open educational resources based on a blended-learning methodology, have been employed to teach the subject of Computer Networks. We have verified not only that the application of OERs into the learning process leads to a significantly improvement of the assessments, but also that the combination of several OERs enhances their effectiveness. These results are supported by, firstly, a study of both students’ opinion and students’ behaviour over five academic years, and, secondly, a correlation analysis between the use of OERs and the grades obtained by students

Safe cooperation between human operators and visually controlled industrial manipulators

Industrial tasks can be improved substantially by making humans and robots collaborate in the same workspace. The main goal of this chapter is the development of a human-robot interaction system which enables this collaboration and guarantees the safety of the human operator. This system is composed of two subsystems: the human tracking system and the robot control system. The human tracking system deals with the precise real-time localization of the human operator in the industrial environment. It is composed of two systems: an inertial motion capture system and an Ultra-WideBand localization system. The robot control system is based on visual servoing. A safety behaviour which stops the normal path tracking of the robot is performed when the robot and the human are too close. This safety behaviour has been implemented through a multi-threaded software architecture in order to share information between both systems. Thereby, the localization measurements obtained by the human tracking system are processed by the robot control system to compute the minimum human-robot distance and determine if the safety behaviour must be activated.Spanish Ministry of Science and Innovation and the Spanish Ministry of Education through the projects DPI2005-06222 and DPI2008-02647 and the grant AP2005-1458

On the early stages of wind-wave generation under accelerated wind conditions

International audienceWhen wind starts to blow, a momentum transfer initiates through the air-water interface generating ocean wave. This transfer is usually characterized in terms of the drag coefficient, CD, but its dependency with wind speed still presents remarkable scatter in the experimental studies. Besides, Babanin and Makin (2008) found that gustiness were responsible to the most distant outliers in drag coefficient values. Also, several studies showed the influence of the sea state and wave age in the roughness and drag coefficient behavior (Smith et al. 1992; Donelan et al. 1993; Drennan 2003). Most of the past studies of wind-waves generation considered uniform and stationary wind speeds. However, in open field it is common to have conditions of wind blowing with a certain acceleration before the constant wind condition is reached. In order to study the early stages of the generation of waves under accelerated wind conditions, a total of five experiments with a characteristic wind speed acceleration were conducted in a large wind-wave facility at the Institut Pytheas (Marseille-France). Momentum fluxes were estimated from hot wire anemometry and, the free surface displacement was measured along the channel tank by resistance and capacitance wire probes. High resolution wind speed and water elevation measurements were acquired at a high resolution rate. During experiments the wind speed was increased with a constant acceleration over time, reaching a constant maximum intensity of 13 m/s. It was observed that during accelerated wind conditions, drag coefficient values depends on the degree of development of the flow regime in the air section and on wave field generation and evolution. The acceleration of wind speed has a direct influence on water surface roughness and water wave evolution in time and in space

A NATO e os desafios até 2030

Este texto está organizado em duas partes interdependentes. A primeira aborda os fatores-chave do condicionamento geopolítico prevalecente; a segunda parte centra-se nos desafios que se colocam à Aliança nesse contexto. Defende, em síntese,a necessidade de um reposicionamento global da nato para o século xxi numa ótica dual track, como forma de continuar a assegurar a dissuasão e defesa coletiva dos aliados mas,simultaneamente, aportar uma atitude de empenhamento político construtivo que a torne uma entidade geradora da estabilidade mundial.Recomenda uma nova sistematizaçãodas relações nato-ue que pode passar pelo desenvolvimento de campanhas completamente integradas e caracteriza algumas das medidas necessárias perante os desafios securitários atuais.This paper and communication is two folded. Firstly, it analyses the key factors conditioning the ongoing world geopolitical dynamics and its impact in the West and particularly in NATO; secondly it focuses on the multiple new emerging challenges to the Alliance, and how NATO should adapt in order to cope with the threats of the upcoming decade. The paper argues for a role shift of the Alliance towards an international actor with global ‘dual track’ responsibility,i.e. to continue ensuring the defence of the Allied Members and deterrence of threats, but at the same time, serve as a democratic agent to promote and sponsor global stability. As a result, this work recommends a stronger relationship architecture between NATO and the EU, focused on the development of integrated capability development programs, as well as shared tactics, techniques and procedures, necessary to counter the multidimensional new rising threats.info:eu-repo/semantics/publishedVersio

Mineralogical and microstructural changes in alkali-activated and hybrid materials exposed to accelerated leaching

Alkali-activated materials (AAM) and hybrid cements (HC) have become sustainable alternatives to Portland cement (PC) due to their low carbon footprint. The main differences between AAM and HC lie in their content of clinker (none in the AAM and usually lower than 30% for HCs) and the type of activator used (strong alkaline solutions for AAM and small amounts of solid alkalis for HC). Durability problems related with microstructural changes due to decalcification and leaching of the cementitious paste have been well researched for PC pastes, but it is still not well known for AAM and HC. The present work aims to study the leaching process for cement pastes of both types of sustainable pastes. Blast furnace slag (BFS) was selected as a precursor to manufacture hybrid slag (HS) pastes and alkali-activated slag (AAS) pastes. A commercial CEM IV was selected as reference material. A 6 M NH4NO3 solution was used to accelerate leaching kinetics. After 28 days of immersion, the mineralogical and microstructural changes were evaluated. Results show that AAS pastes exhibited the highest leaching resistance of all the pastes under study, due to the absence of portlandite and the high level of polymerization of silicate chains. In HS pastes, the presence of portlandite (due to PC in the material) and gypsum (due to the activator) explains their intermediate performance, in between CEM IV and AAS.The authors have been able to carry out the present research thanks to financial support from the Ministerio de Ciencia, Innovación y Universidades of Spain (RTI2018-096428-B-I00 and PID2020-116738RJ-I00 projects) and Madrid Government (Comunidad de Madrid) under the Multiannual Agreement UC3M in the line of "Fostering Young Doctors Research" (HORATSO-CS-UC3M) in the context of the V PRICIT (Regional Programme of Research and Technological Innovation)

Propuesta didáctica para la detección y mejora de las actitudes posturales incorrectas de la columna

En este artículo realizamos una propuesta didáctica que tiene los siguientes objetivos: conocer la morfología normal de la columna, detectar anomalías en dicha morfología, así como discernir cuáles son debidas a hábitos posturales incorrectos. Finalmente proponemos un plan de ejercicios que los corrija