Fatores intrínsecos associados a dor no ombro em praticantes de surf: um estudo de caso-controlo

Background: The demands of a sport such as surfing are high, paddling is one of the most common movements during a surfing session and therefore the load on the shoulder joint increases. Despite growing evidence regarding surf-related injuries, risk factors should be taking into consideration in a deeper analysis. This study was designed to contribute to greater knowledge of intrinsic factors that may be associated with shoulder injuries. Objective: The aim of this study is to determine if physical characteristics such as range of motion, shoulder strength, proprioception, scapular dyskinesia, core endurance and pectoralis minor length might be associated with shoulder injuries in surfers. Methods: Forty-one surfers aged between 18 and 45 years enrolled this study. Firstly, a socio-demographic questionnaire was filled out addressing anthropometric features and previous pain history (three months prior), the second part, an assessment was carried out: range of motion (ROM), shoulder muscle strength, proprioception (joint position sense), core endurance and pectoralis minor length was measured. Results: Shoulder active range of motion values did not differ between both groups. Normalized shoulder strength and IR:ER ratios for surfers with and without shoulder pain history was not significantly different. End-range position (80º) showed minor relative error scores on surfers who reported previous pain history. There is no correlation between dyskinesia and shoulder pain. Pectoralis minor length did not shown association with a painful shoulder. Symptomatic surfers did show differences in core endurance regarding prone bridge test. Conclusion: Shoulder pain is a recurring symptom both in competitive and free-surfers. All shoulder parameters: range of motion, strength, dyskinesia, pectoralis minor length, side bridge test, CKCUEST were independent of a history of pain story. End-range (80º) proprioception as well as prone bridge test shown significant differences between surfers who reported previous pain and surfers who did not have previous complains. This study provides a basis for more studies to carry on surf investigation

Structured Control of LPV Systems with Application to Wind Turbines

Abstract — This paper deals with structured control of linear parameter varying systems (LPV) with application to wind turbines. Instead of attempting to reduce the problem to linear matrix inequalities (LMI), we propose to design the controllers via an LMI-based iterative algorithm. The proposed algorithm can synthesize structured controllers like decentralized, static output and reduced order output feedback for discrete-time LPV systems. Based on a coordinate decent, it relies on a sufficient matrix inequality condition extended with slack variables to an upper bound on the induced L2-norm of the closed-loop system. Algorithms for the computation of feasible as well as optimal controllers are presented. The general case where no restrictions are imposed on the parameter dependence is treated here due to its suitability for modeling wind turbines. A comprehensive numerical example of a gain-scheduled LPV controller design with prescribed pattern for wind turbines illustrate the utilization of the proposed algorithm. I

Family or firm? Why are the women the hardest hit by the pandemic economic crisis

One striking effect of the pandemic economic crisis is the disproportionate adverse impact on women. This paper explores the roots of the gender heterogenous effects, using two rich and new micro-level data bases. By formulating two hypotheses -the gender role and the sectorial composition hypothesis-we find that women are being severely affected by the current pandemic economic crisis both due to their traditional role as mothers and wives but also due to their prevalence in the hardest hit sectors such as accommodation and food services

Comportamento do ácido aconítico e da vinhaça no solo.

A vinhaça é um efluente poluente, advindo de destilarias de álcool, no qual ocorre o ácido aconítico (AA), um componente com atividade alelopática sobre espécies de plantas daninhas. Dois experimentos foram instalados com o objetivo de determinar os efeitos da vinhaça na germinação e no crescimento do caule e raízes e raízes do amendoim-bravo (Euphorbia heterophylla), introduzido no Agar e no solo, em condições de laboratório. Tratamentos com doses de até 15 mM de AA e de vinhaça, complementados com maiores níveis de umidade no solo, foram estabelecidos. Os resultados indicaram comportamentos diferenciados do AA no meio de cultivo do amendoim-bravo, sendo mais inibitório no Agar. Doses de AA a 10 mM inibiram acentuadamente o amendoim-bravo no Agar, enquanto que doses de até 15 mM no solo não indicaram nehuma inibição. Por sua vez, a vinhaça inibiu totalmente o amendoim-bravo no Agar na dose diluída de até 1/8 de vinhaça, enquanto que no solo a dose de 1/2 tendeu a produzir uma inibição não significativa da germinação e crescimento do amendoim-bravo. A adição de maior nível de umidade no solo teve efeito negativo sobre a germinação. A aplicação de AA em Agar favoreceu o aumento de fungos sobre as sementes de amendoim-bravo, bem como aumentos de umidade do solo ou aumentos de vinhaça, na superfície do mesmo