Kinematic analysis of the standing long jump in children 6- to 12-years-old     

Jorge R. Fernandez-Santos  Jose Luis Gonzalez-Montesinos  Jonatan R Ruiz  David Jiménez-Pavón  Jose Castro-Piñero 《Measurement in physical education and exercise science》2018,22(1):70-78

The purpose of this study was to analyze the kinematic variables that determine the performance of the standing long jump in children 6- to 12-years-old. There were 121 healthy children (58 girls) recorded while they performed the standing long jump test. All kinematic variables showed a significant correlation with calculated jump distance and measured jump distance, except for the knee joint angle at maximum shoulder extension angle, ankle joint angle at maximum shoulder extension angle, and shoulder joint angle at maximum knee flexion angle. Stepwise multiple regression analysis showed that sex, age, and body mass index accounted for 51.1% of the jump distance variance. Among all the kinematic variables, take-off distance and take-off speed were accounted for the most of the variation in the jump distance. Physical education teachers and coaches should consider special attention to these anthropometrics and kinematic aspects in improving the standing long jump performance in children.  相似文献   

Potential adverse cardiac remodelling in highly trained athletes: still unknown clinical significance     

Luigi Gabrielli  Marta Sitges  Mario Chiong  Jorge Jalil  María Ocaranza  Silvana Llevaneras 《European Journal of Sport Science》2018,18(9):1288-1297

Moderate endurance exercise has long been considered an essential element to maintain cardiovascular health, and sedentary behaviour in the general population has been related to a significant increase in all-causes of mortality, cardiovascular disease mortality and cardiovascular disease incidence. However, a growing group of people performs an intense exercise that leads to multiple heart adaptive changes that are collectively called “athlete’s heart”. In this review, we discussed the evidence of cardiac remodelling process secondary to repetitive and strenuous exercise in some predisposed athletes that produces intense and probably deleterious changes in cardiac morphology and function with no clear clinical significance in long-term follow-up. Moreover, we also discussed the individual biological response to exercise assessed by myocardial damage, inflammation, oxidative stress, fibrosis and ventricular hypertrophy biomarkers showing different intensities with equivalent exertion.  相似文献   

RHONN identifier-control scheme for nonlinear discrete-time systems with unknown time-delays     

Jorge D. Rios  Alma Y. Alanis  Carlos Lopez-Franco  Nancy Arana-Daniel 《Journal of The Franklin Institute》2018,355(1):218-249

This work presents a neural identifier-control scheme for uncertain nonlinear discrete-time systems with unknown time-delays. This scheme is based on a neural identifier to get a model of the system and a discrete-time block control technique based on sliding modes to generate the control law. The neural identifier is based on a Recurrent High Order Neural Network (RHONN) trained with an Extended Kalman Filter (EKF) based algorithm. Applicability is shown using real-time test results for linear induction motors. Also, a Lyapunov analysis is added in order to prove the semi-globally uniformly ultimately boundedness (SGUUB) of the proposed neural identifier-control scheme.  相似文献   

Robust sensorless observer-based adaptive sliding modes control of synchronous motors     

Jediael Machín Almeida  Alexander G. Loukianov  José M. Cañedo Castañeda  Jorge Rivera Dominguez 《Journal of The Franklin Institute》2018,355(7):3221-3248

Using a nonlinear complete order model of a synchronous motor, a robust second order sliding mode observer based control scheme is proposed. For that, a generalized super-twisting 3rd order observer is proposed for nonlinear systems. Based on the proposed observer scheme, a robust rotor flux observer is designed, then, a stator current observer is proposed using a classical super-twisting algorithm for extracting information of the rotor speed by means of the equivalent control method. The control design for the output tracking of a desired reference signal for the rotor speed is carried out with a classical super-twisting sliding mode algorithm and adaptive backstepping techniques. Due to the number of inputs, the flux in the excitation winding, and the direct component of the stator currents are also regulated. Numeric simulations predict a good performance of the closed-loop synchronous motor with parameter variations.  相似文献   

Uncovering the link between governance as an innovation process and socio-economic regime transition in cities     

Geoff Simmons  Jorge Esteban Diez Giraldo  Yann Truong  Mark Palmer 《Research Policy》2018,47(1):241-251

A major proportion of the world’s population will be located in cities by 2030. With cities globally facing challenges due to the social exclusion of significant proportions of their populace, new thinking is needed on ways to correlate the competing socio-economic goals of various actors. This study sought to uncover the link between governance in cities as an innovation process and socio-economic regime transition towards a more equitable urban society. To do so, we draw on transition management thinking to consider urban regime transitions evolving in a temporal and incremental manner and in a multi-level context. We sought expansion from a delimited focus on socio-technical regimes in transition management literature to incorporate the notion of urban socio-economic regimes. This involved integrating aspects of reflexive governance and politics in a city context with a basic ontology of complex social systems and their evolutionary dynamics that underlies transition management approaches. Our focus is on learning by doing and experimentation as well as participation of citizens with other key city actors in a radically new process of mutual learning that creates social inclusion. The juxtaposition of national, city and community level interactions and their impact on socio-economic regime transition brings into sharp relief the issue of spatial scale and a lack of consideration in transition approaches generally. The study findings reveal a spatial orientation for creating new urban forms of reflexive governance as an innovation process taking place in transition arenas that can trigger new pathways to socio-economic change.  相似文献   

When the clock starts ticking: Measuring strategic responses to TRIPS's patent term change     

Jorge Lemus  Guillermo Marshall 《Research Policy》2018,47(4):796-804

  相似文献   

The new supply chain's frontier: Information management     

Jorge Verissimo   《International Journal of Information Management》2009,29(5):372-379

The purpose of this paper is to understand the key issues faced by supply chain (SC), current strategies and trends of this field, understand IT technical issues and implication for business performance and how IT can foster IM and help sort out the SC problems. Studies from different and recognised authors are reviewed, compiled and analysed in two aspects. First, a detailed picture of SC trends, issues and strategies is depicted. After, main concerns about IT, such as its goals, importance, pitfalls, and features are presented. Moreover, current applications of IT in SC and critical problems and competitive advantages in the IT implementation in the supply chain management's competitive priorities are detailed. SC's new configuration and reality have increased the level of uncertainties and risks present in supply chain activities. Some strategies to mitigate these problems have undermined the SC efficiency. Therefore, a new strategy that uses IT to make SC more robust and resilient should be developed. As a holistic problem, a modelling approach (SDDES) should be used as a tool to support this study.  相似文献   

Paraprofessionals use of group school-based instrumental mentoring: Examining process and preliminary outcomes     

Gerald G. Strait  Jenna Turner  Diana Stinson  Samanthia Harrison  Rojan Bagheri  Tanya Perez  Bradley H. Smith  Jorge Gonzalez  Jacqueline R. Anderson  Jill Simpson  Sam D. McQuillin 《Psychology in the schools》2020,57(9):1492-1505

Many schools use paraprofessionals to implement and monitor interventions. Though paraprofessionals are cost-effective, many questions remain about the training and skills they need to implement a wide array of school-based interventions. In this study, we compare paraprofessionals' (i.e., undergraduates) implementation of the Group-Academic Mentoring Program for Education Development (Group-AMPED) to school psychology graduate students' implementation of Group-AMPED. Ten paraprofessionals and five school psychology graduate students provided approximately eight sessions of Group-AMPED to 35 sixth-grade students. Results indicated no significant differences between middle school students' engagement when groups were led by either school psychology graduate students or paraprofessionals. Similarly, self-reports of fidelity and supervisor postsession implementation confidence indicated no difference between paraprofessionals and graduate students' implementation of Group-AMPED. Follow-up measures indicated that mentors and proteges perceived Group-AMPED as feasible, acceptable, and understandable. Most importantly, middle school students participating in Group-AMPED had significantly higher second-semester grades in comparison to a small control group.  相似文献   

Application of antigenic biomarkers for Mycobacterium tuberculosis     

Rodríguez-Hernández  Elba  Quintas-Granados  Laura Itzel  Flores-Villalva  Susana  Cantó-Alarcón  Jorge Germinal  Milián-Suazo  Feliciano 《Journal of Zhejiang University. Science. B》2020,21(11):856-870

Journal of Zhejiang University-SCIENCE B - The study and characterization of biomolecules involved in the interaction between mycobacteria and their hosts are crucial to determine their roles in...  相似文献   

Towards the use of multidimensional performance indicators in football small-sided games: the effects of pitch orientation     

Hugo Folgado  Jorge Bravo  Paulo Pereira  Jaime Sampaio 《Journal of sports sciences》2019,37(9):1064-1071

This study aimed to compare youth football players’ performance during two small-sided games with different pitch orientation: i) 40x30m and ii) 30x40m formats. Twenty under-15 players (age = 14.1 ± 0.5 years) participated in nine GK+4vs4+GK situations in each format, with the duration of six minutes each. Positional data were collected using individual GPS units, and computed for tactical and physical performance indicators. The SSG were video recorded, using notational analysis for collecting technical indicators. A novel method that incorporates time dependent notational information with spatiotemporal data was used to compute multidimensional parameters. Standardised effect sizes and non-clinical magnitude-based inferences were used to compare formats. Results showed that players covered more distance at higher intensities, presented more passes and dribbles and were more synchronised in the longitudinal axis while playing in the 40x30m pitch. In the 30x40m pitch, results showed a lower distance between team centroids, higher number of shots, more lateral passes and a wider team positioning. Multidimensional indicators, as players position and distance to the closest defender while shooting, revealed a more constant distance between attacker and defender in the 40x30m pitch. These results highlight the importance of integrating information from different indicators for a contextually valid information.  相似文献