Optimization and performance criteria of a Stokes polarimeter based on two variable retarders

In this paper we present the analysis, optimization and implementation of several Stokes polarimeter configurations based on a setup including two variable retarders. The polarimeter analysis is based on the Mueller-Stokes formalism, and as a consequence, it is suitable to deal with depolarized light. Complete Stokes polarimeters are optimized by minimizing the amplification of simulated errors into the final solution. Different indicators useful to achieve this aim, as the condition number or the equally weighted variance, are compared in this paper. Moreover, some of the optimized polarimeters are experimentally implemented and it is studied the influence of small deviations from the theoretical ones on the amplification of the Stokes component error. In addition, the benefit of using incomplete polarimeters, when detecting specific ranges of states of polarization, is discussedFil: Peinado, Alba. Universitat Autonoma de Barcelona; EspañaFil: Lizana, Ángel. Universitat Autonoma de Barcelona; EspañaFil: Vidal, Josep. Universitat Autonoma de Barcelona; España. ALBA Synchrotron Light Source Facility; EspañaFil: Iemmi, Claudio Cesar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Campos, Juan. Universitat Autonoma de Barcelona; Españ

Microparticle manipulation and imaging through a self-calibrated liquid crystal on silicon display

We present in this paper a revision of three different methods we conceived in the framework of liquid crystal on silicon (LCoS) display optimization and application. We preliminarily demonstrate an LCoS self-calibration technique, from which we can perform a complete LCoS characterization. In particular, two important characteristics of LCoS displays are retrieved by using self-addressed digital holograms. On the one hand, we determine its phase-voltage curve by using the interference pattern generated by a digital two-sectorial split-lens configuration. On the other hand, the LCoS surface profile is also determined by using a self-addressed dynamic micro-lens array pattern. Second, the implementation of microparticle manipulation through optical traps created by an LCoS display is demonstrated. Finally, an LCoS display based inline (IL) holographic imaging system is described. By using the LCoS display to implement a double-sideband filter configuration, this inline architecture demonstrates the advantage of obtaining dynamic holographic imaging of microparticles independently of their spatial positions by avoiding the non-desired conjugate images

Compact LCOS–SLM Based Polarization Pattern Beam Generator

In this paper, a compact optical system for generating arbitrary spatial light polarization patterns is demonstrated. The system uses a single high-resolution liquid crystal (LC) on silicon (LCOS) spatial light modulator. A specialized optical mount is designed and fabricated using a 3D printer, in order to build a compact dual optical architecture, where two different phase patterns are encoded on two adjacent halves of the LCOS screen, with a polarization transformation in between. The final polarization state is controlled via two rotations of the Poincaré sphere. In addition, a relative phase term is added, which is calculated based on spherical trigonometry on the Poincaré sphere. Experimental results are presented that show the effectiveness of the system to produce polarization patterns

Prevalence of Diabetes Mellitus and Its Associated Unfavorable Outcomes in Patients With Acute Respiratory Syndromes Due to Coronaviruses Infection: A Systematic Review and Meta-Analysis

Introduction: Only 3 types of coronavirus cause aggressive respiratory disease in humans (MERS-Cov, SARS-Cov-1, and SARS-Cov-2). It has been reported higher infection rates and severe manifestations (ICU admission, need for mechanical ventilation, and death) in patients with comorbidities such as diabetes mellitus (DM). For this reason, this study aimed to determine the prevalence of diabetes comorbidity and its associated unfavorable health outcomes in patients with acute respiratory syndromes for coronavirus disease according to virus types. Methods: Systematic review of literature in Pubmed/Medline, Scopus, Web of Science, Cochrane, and Scielo until April of 2020. We included cohort and cross-sectional studies with no restriction by language or geographical zone. The selection and extraction were undertaken by 2 reviewers, independently. The study quality was evaluated with Loney’s instrument and data were synthesized by random effects model meta-analysis. The heterogeneity was quantified using an I2 statistic. Funnel plot, Egger, and Begg tests were used to evaluate publication biases, and subgroups and sensitivity analyses were performed. Finally, we used the GRADE approach to assess the evidence certainty (PROSPERO: CRD42020178049). Results: We conducted the pooled analysis of 28 studies (n = 5960). The prevalence analysis according to virus type were 451.9 diabetes cases per 1000 infected patients (95% CI: 356.74-548.78; I2 = 89.71%) in MERS-Cov; 90.38 per 1000 (95% CI: 67.17-118.38) in SARS-Cov-1; and 100.42 per 1000 (95% CI: 77.85, 125.26 I2 = 67.94%) in SARS-Cov-2. The mortality rate were 36%, 6%, 10% and for MERS-Cov, SARS-Cov-1, and SARS-Cov-2, respectively. Due to the high risk of bias (75% of studies had very low quality), high heterogeneity (I2 higher than 60%), and publication bias (for MERS-Cov studies), we down rate the certainty to very low. Conclusion: The prevalence of DM in patients with acute respiratory syndrome due to coronaviruses is high, predominantly with MERS-Cov infection. The unfavorable health outcomes are frequent in this subset of patients. Well-powered and population-based studies are needed, including detailed DM clinical profile (such as glycemic control, DM complications, and treatment regimens), comorbidities, and SARS-Cov-2 evolution to reevaluate the worldwide prevalence of this comorbidity and to typify clinical phenotypes with differential risk within the subpopulation of DM patients.Revisión por pare

Self-addressed diffractive lens schemes for the characterization of LCoS displays

Ponència presentada a: Emerging Liquid Crystal Technologies (San Francisco, California: 13th, 27 January - 1 February 2018)We proposed a self-calibration method to calibrate both the phase-voltage look-up table and the screen phase distribution of Liquid Crystal on Silicon (LCoS) displays by implementing different lens configurations on the studied device within a same optical scheme. On the one hand, the phase-voltage relation is determined from interferometric measurements, which are obtained by addressing split-lens phase distributions on the LCoS display. On the other hand, the surface profile is retrieved by self-addressing a diffractive micro-lens array to the LCoS display, in a way that we configure a Shack-Hartmann wavefront sensor that self-determines the screen spatial variations. Moreover, both the phase-voltage response and the surface phase inhomogeneity of the LCoS are measured within the same experimental set-up, without the necessity of further adjustments. Experimental results prove the usefulness of the above-mentioned technique for LCoS displays characterization

A influência de diferentes formatos de jogos nos aspectos técnicos e táticos de jogadores de futebol

O objetivo do estudo foi investigar a influência da dimensão do campo e do número de jogadores nos aspectos táticos e técnicos em diferentes formatos de jogos. Para tanto, quatorze jogadores de futebol pertencentes à categoria sub-20 participaram de três estruturas de jogos distintas: Gr+3vs3+Gr (27x18 m), Gr+6vs6+Gr (52x32 m) e Gr+10vs10+Gr (105x64 m), em duas condições: Jogo Controle e Jogo de Manutenção. Os jogos foram filmados por quatro câmeras de vídeos digitais. Posteriormente, as sequências de imagens foram analisadas no software Dvideo, que possibilitou obter a posição de todos os jogadores em função do tempo e o registro das ações técnicas ocorridas. Desse modo, foram analisadas as variáveis táticas “Centro de Jogo” e “Densidade Ofensiva” (igualdade numérica, superioridade ofensiva e defensiva), assim como as variáveis técnicas de passe, domínio, condução, finalização, desarme, interceptação e carga técnica. Os resultados mostraram diferenças significativas nos indicadores táticos de participação no centro de jogo (p<0.01), igualdade numérica (p<0.01), superioridade defensiva (p<0.01) e ofensiva(p<0.05). Em relação às ações técnicas, foi possível verificar diferenças significativas no passe (p<0.01), domínio (p<0.01), condução (p<0.01), finalização (p<0.01), desarme (p<0.05), interceptação (p<0.01) e na carga técnica (p<0.01). Concluímos que, a manipulação da dimensão do campo e do número de jogadores influencia a emergência de comportamentos técnico-táticos específicos, o que possibilita treinadores adequarem as estruturas dos jogos para a elaboração de exercícios que estejam de acordo com os seus objetivos pedagógicos

Generation of reconfigurable optical traps for microparticles spatial manipulation through dynamic split lens inspired light structures

We present an experimental method, based on the use of dynamic split-lens configurations, useful for the trapping and spatial control of microparticles through the photophoretic force. In particular, the concept of Split- lens configurations is exploited to experimentally create customized and reconfigurable three-dimensional light structures, in which carbon coated glass microspheres, with sizes in a range of 63-75 pm, can be captured. The generation of lightspatial structures is performed by properly addressing phase distributions corresponding to different split-lens configurations onto a spatial light modulator (SLM). The use of an SLM allows a dynamic variation of the light structures geometry just by modifying few control para meters of easy physical interpretation. We provide some examples in video format of particle trapping processes. What is more, we also perform further spatial manipulation, by controlling the spatial position of the particles in the axial direction, demonstrating the generation of reconfigurable three-dimensional photophoretic traps for microscopic manipulation of absorbing particles

Dynamic microparticle manipulation through light structures generated by a self-calibrated Liquid Crystal on Silicon display

Ponència presentada a: Unconventional Optical Imaging (Strasbourg, France: 22-26 April 2018)This paper is devoted to investigate the application of different dynamic light structures generated by a self-calibrated Liquid Crystal on Silicon (LCoS) display for microparticle manipulation. Two major studies based on implementing different DOEs, to thoroughly characterize the LCoS display and to achieve optical-inspired particle manipulation, are proposed, respectively. On the one hand, we dynamically introduced the billet-lens configuration and the micro-lens array pattern on the LCoS display, from which the self-calibration of the studied device is implemented. In this case, both the phase-voltage relation and the surface profile were determined and optimized to the optimal performance for microparticle manipulation. On the other hand, we performed the optical manipulation of microparticles by addressing configurable three-dimensional light structures obtained from different phase driven split-lens configurations initiated by the same but optimized LCoS display. Experimental results demonstrated that, by addressing certain phase distributions on the LCoS display, the microparticle can be trapped in the light cones and manipulated by providing certain continuous split-lens configurations

Effect of therapeutic exercise on joint range and strength in throwing athletes with dyskinesia. A systematic review

El objetivo de este estudio fue determinar los efectos del ejercicio terapéutico (ET) sobre los cambios de rangos de movimiento (ROM) y la fuerza muscular (FM) en deportistas lanzadores que presentan disquinesia escapular (DE). Se realizó la búsqueda en Pubmed, Scopus, Web of Science, ScienceDirect de los últimos cinco años según la metodología PRISMA, considerando estudios que describieran los efectos de los programas de ejercicio terapéutico en rango articular y fuerza muscular de deportistas lanzadores. Se incluyeron un total de seis artículos relacionado con deportistas lanzadores con disquinesia escapular. Se encontraron resultados favorables dentro de las intervenciones que contaban con ET, el cual obtuvo un efecto significativo en las variables de ROM y fuerza muscular en deportistas lanzadores. En conclusión, los ejercicios de estiramientos terapéuticos son la herramienta más favorable y eficaz frente a cualquier otro tipo de intervención, teniendo un efecto sobre la FM y el ROM de los atletas lanzadores, ayudando así a su rendimiento competitivo.The aim of this study was to determine the effect of using therapeutic exercise (TE) on changes in the range of motion (ROM) and muscle strength (MS) in throwing athletes with scapular dyskinesis (SD).A systematic review was carried out in databases (Pubmed, Scopus, WoS, ScienceDirect) over the last five years, searching for randomized clinical trials, cohort studies, meta-analyses and concept reviews that met the inclusion, exclusion, and methodological quality criteria.A total of six articles related to throwing athletes with scapular dyskinesia were included. Favorable results were found within the interventions that included TE, which obtained a significant effect on the variables of ROM and muscle strength in throwing athletes.In conclusion,therapeutic stretching exercises are the most favorable and effective tool compared to any other type of intervention, having an effect on the MS and ROM of throwing athletes, thus helping their competitive performance