The bandwidth knowledge of results regarding the task of the overhand serve in volleyball

Abstract Aim: Motor learning is considered a complex process, providing numerous investigations. Knowledge of Results (KR), a kind of extrinsic feedback, is one of the variables that are used for investigations on motor learning. There are different ways to provide KR to optimize motor learning. The bandwidth KR is one of these forms, being a factor that affects motor learning, however, the specificity of the task needs to be considered in the investigation of this theme. Thus, the objective of the study is to analyze the bandwidth of KR in the acquisition of motor skills of the overhand serve in volleyball. Methods: The sample consisted of 24 volunteers of both sexes (12 men and 12 women), 18 to 35 years of age (M = 27, SD = 3.46) and inexperienced in the task. The effect of the bandwidth was analyzed in two groups (with range and without range), in which the volunteers had to learn to control their force by performing the volleyball tennis type service in order to hit a target line. Performance was inferred by the mean and standard deviation of absolute, constant and variable errors. Results: There was no statistically significant difference between the groups and the volunteers improved both the precision (absolute error and constant error) and in the consistency (variable error) during the acquisition. There was an improvement in the groups also in the transfer test in the precision measures. Conclusion: The variable bandwidth is similar to a control condition in which the volunteers have information at each attempt, causing dependence on external information.

Análisis de fase en estudios Gated-SPECT como predictor de mortalidad en pacientes con enfermedad coronaria y función ventricular izquierda deprimida / Phase analysis in Gated-SPECT studies as a predictor of mortality in patients with coronary diseases and impaired left ventricular function

Resumen Antecedentes: La enfermedad coronaria es una de las principales causas de morbimortalidad en los países occidentales. En etapas avanzadas de la enfermedad, los procesos de remodelación miocárdica pueden conducir a insuficiencia cardíaca progresiva y disfunción ventricular izquierda. El análisis de fase de los estudios de perfusión miocárdica Gated-SPECT muestra parámetros que han sido caracterizados como marcadores válidos de asincronía ventricular. Objetivo: Evaluar los parámetros del análisis de fase en Gated-SPECT como predictores independientes de mortalidad en pacientes con enfermedad coronaria avanzada e insuficiencia ventricular izquierda. Materiales y método: Estudio retrospectivo de cohortes históricas de 185 pacientes consecutivos (140 hombres; edad media=67,6±12,7 años) a los que, entre enero de 2009 y marzo de 2011, se les hizo estudio isotópico de perfusión miocárdica con estimulación farmacológica con resultado positivo para isquemia/necrosis con FEVI ≤ 55%. Adicionalmente, se les realizó seguimiento medio de 32,4±10,5 meses registrándose la aparición de eventos cardíacos mayores (infarto agudo de miocardio no mortal, ingreso hospitalario y revascularización coronaria tardía) y mortalidad total. Resultados: Durante el seguimiento se registraron eventos mayores en 51 pacientes así como 28 fallecimientos, de los cuales, 82,1% mostró valores alterados de los parámetros de fase: media=141,1(±17,6(; desviación estándar=15,8(±10,1(; ancho de banda=59,1(±36( y FEVI=42,4%±10,8%. El análisis de Cox mostró al ancho de banda como un predictor independiente de muerte, disminuyendo significativamente la supervivencia y aumentando el riesgo de muerte (hazard ratio=2,68; p<0,05). Conclusiones: El ancho de banda en el análisis de fase se comporta como un predictor independiente de muerte en pacientes con miocardiopatía conocida y FEVI deprimida.

Abstract Background: Coronary disease is one of the main causes of morbidity and mortality in western countries. In the advanced stages of the disease the myocardial remodelling processes can lead to progressive heart failure and left ventricular impairment. The phase analysis of Gated-SPECT studies of myocardial perfusion show parameters that have been characterised as valid marker of ventricular asynchrony. Objective: To evaluate the phase analysis parameters in Gated SPECT as independent predictors of mortality in patients with advanced coronary disease and left ventricular failure. Materials and method: A retrospective historic cohort study was conducted on 185 consecutive patients (140 males; mean age = 67.6±12.7 years) on whom, between January 2009 and March 2011, an isotope myocardial perfusion study was carried out with pharmacologic stimulation and with a positive result for ischaemia / necrosis, and with a LVEF ≤ 55%. A mean follow-up of 32.4 ±10.5 months was also performed, recording the appearance of major cardiac events (non-fatal acute myocardial infarctions, hospital admission, delayed coronary revascularisation, and total mortality. Results: Major events were recorded in 51 patients during follow-up. There were also 28 deaths, of which 82.1% showed abnormal values of the phase parameters: media=141.1(±17.6(; standard deviation=15.8(±10.1(; bandwidth=59.1(±36(, and LVEF = 42.4%±10.8%. The Cox analysis showed the bandwidth as an independent predictor of death, significantly reducing the survival and increasing the risk of death (hazard ratio=2.68; P<.05). Conclusions: The bandwidth in the phase analysis behaves as an independent predictive factor in patients with known myocardial disease and an impaired LVEF.

Faixa de amplitude de feedback aumenta a consistência do desempenho de habilidades motoras / Bandwidth feedback increases performance consistency of motor skills

Introdução: A faixa de amplitude de conhecimento de resultados pode auxiliar o desempenho de habilidades motoras. Objetivo: Investigar o efeito da faixa de amplitude de conhecimento de resultados na consistência do desempenho de habilidades motoras. Método: Participaram do estudo 30 voluntários separados aleatoriamente nos grupos faixa de amplitude 15%, que recebeu conhecimento de resultados quando o erro estava além da faixa estipulada; e controle, que recebeu conhecimento de resultados após cada tentativa. A tarefa consistiu em pressionar quatro teclas no teclado alfanumérico do computador, na sequência, 2,8,6,4 com o dedo indicador da mão direita com tempo alvo de 900ms. A variável independente foi manipulada nas 60 tentativas da fase de aquisição. O teste de retenção foi realizado após 24h, com 10 tentativas. Resultados: O desempenho do faixa de amplitude 15% foi mais consistente durante a fase de aquisição e no teste de retenção. Conclusão: A faixa de amplitude tem alta probabilidade de melhorar a consistência no desempenho de habilidades motoras.

Introduction: The bandwidth knowledge of results can assist the performance of motor skills. Objective: Investigate the effect of bandwidth knowledge of results on performance consistency of motor skills. Method: Participated of the study 30 volunteers randomly assigned on groups bandwidth of 15%, which received knowledge of results when the error was beyond the stipulated bandwidth; and control, which received knowledge of results after every trial. The task consisted of pressing four keys on a computer alphanumeric keyboard in the sequence, 2, 8, 6 and 4 using the index finger of the right hand, with the target time of 900ms. The independent variable was manipulated on the 60 trials of the acquisition phase. The retention was performed 24 hours later, with 10 trials. Results: The performance of the bandwidth of 15% was more consistent during the acquisition phase and the retention test. Conclusion: The bandwidth has high probability to improve performance consistency of motor skills.

Left ventricle segmentation in echocardiography based on adaptive mean shift / 生物医学工程学杂志

The use of echocardiography ventricle segmentation can obtain ventricular volume parameters, and it is helpful to evaluate cardiac function. However, the ultrasound images have the characteristics of high noise and difficulty in segmentation, bringing huge workload to segment the object region manually. Meanwhile, the automatic segmentation technology cannot guarantee the segmentation accuracy. In order to solve this problem, a novel algorithm framework is proposed to segment the ventricle. Firstly, faster region-based convolutional neural network is used to locate the object to get the region of interest. Secondly, -means is used to pre-segment the image; then a mean shift with adaptive bandwidth of kernel function is proposed to segment the region of interest. Finally, the region growing algorithm is used to get the object region. By this framework, ventricle is obtained automatically without manual localization. Experiments prove that this framework can segment the object accurately, and the algorithm of adaptive mean shift is more stable and accurate than the mean shift with fixed bandwidth on quantitative evaluation. These results show that the method in this paper is helpful for automatic segmentation of left ventricle in echocardiography.

Investigation and practice of magnetic field homogeneity evaluation methods for MRI equipment / 中国医学影像技术

Objective To explore the evaluation methods of magnetic field uniformity and the practical operations,in order to provide references for clinical quality control.Methods Based on MRS phantom and 32 cm uniform spherical phantom,the evaluation methods of magnetic field uniformity were used to detect MRI equipment in department of radiology,including spectral peak and the bandwidth difference.Results The full width at half maximum (FWHM) of MRS phantom was 0.08 ppm,the inhomogeneity values on coronal,sagittal and axial detected by the bandwidth difference method was 0.15 ppm,0.08 ppm and 0.18 ppm,respectively.Conclusion The magnetic field homogeneity of the above mentioned MRI equipment is favorable,which accords with magnetic field uniformity detection standard.

Efeitos de faixas de amplitude de CP na aprendizagem do saque tipo tênis do voleibol / Effects of the bandwidth KP on the learning of the volleyball tennis serve

Este estudo teve como objetivo investigar os efeitos de duas faixas de amplitude de Conhecimento de Performance (CP) na aprendizagem do saque tipo tênis do voleibol. Essa questão foi testada com uma faixa de amplitude estreita e uma ampla e mais um grupo controle. O estudo foi composto por um pré-teste, fase de aquisição e teste de retenção. Foram analisadas medidas de desempenho e dos componentes do padrão da habilidade. Apesar dos grupos mostrarem desempenho semelhante no teste de retenção, a faixa ampla foi a única que levou a melhora do desempenho. Além disso, a faixa ampla conduziu a mais mudanças no padrão da habilidade do que a faixa estreita ou o grupo controle.

This study aimed to investigate two bandwidth Knowledge of Performance (KP) effects on the learning of the volleyball tennis serve. This question was tested with a thin and wide bandwidth KP plus a control group. The study was composed by a pre test, acquisition phase and retention test. It was analyzed performance and components of the motor pattern measures. Although the groups showed similar performance on retention test, only wide bandwidth conducted to a better performance. Although all groups showed similar performance during retention test only the wide bandwidth conducted to performance improvement. Moreover, the wide bandwidth conducted to more changes in movement pattern than thin bandwidth or control group.

Influences of clock resolution of bandwidth measurement on packet pair algorithm / 药物分析学报

Influences of the clock resolution of bandwidth estimator on the accuracy and stability of the packet pair algorithm was analyzed. A mathematic model has been established to reveal the relationship between the result deviation coefficient and the packet size, clock resolution and real bandwidth(value)of the measured route. A bandwidth self-adapting packet pair algorithm was presented based on the mathematic model to reduce the estimation error resulting from the clock resolution and to improve the accuracy and stability of measurement by adjusting the deviation coefficient. Experimental results have verified the validity and stability of the algorithm.

Influences of clock resolution of bandwidth measurement on packet pair algorithm / 西安交通大学学报·英文版

Influences of the clock resolution of bandwidth estimator on the accuracy and stability of the packet pair algorithm was analyzed. A mathematic model has been established to reveal the relationship between the result deviation coefficient and the packet size, clock resolution and real bandwidth (value) of the measured route. A bandwidth self-adapting packet pair algorithm was presented based on the mathematic model to reduce the estimation error resulting from the clock resolution and to improve the accuracy and stability of measurement by adjusting the deviation coefficient. Experimental results have verified the validity and stability of the algorithm.

Small-signal pre-amplifying circuit for microwave-induced thermoacoustic tomography / 医疗卫生装备

In order to improve the noise ratio and stability of the amplified small-signal in microwave-induced thermoacoustic tomography,an amplifying circuit with wide band and high voltage gain is designed in this paper.The results show that the voltage gain is up to 80dB and the bandwidth is about 7MHz.

Medical Information Network Construction for the Large Scale General Hospital Information System: A Case of Seoul National University Hospital / 대한의료정보학회지

Recently, it becomes conspicuous that the network should have enough communication bandwidth and be organized with steadiness to operate and support hospital information system successfully. Seoul National University Hospital completed to reconstruct legacy network which had been used since 1995. We had a consultation to diagnose the current problems and reconstructed the network according to the consultation. The design of network architecture was mainly focused on the circuit route in case of error condition and the suitable bandwidth for the easy communication. We also regulated the use of unsuitable protocols which might broadcast inappropriate data packets over the whole network. After 6 months of operation we evaluated the performance of newly constructed network. The average traffic rate from the input port of main servers was 0.5% and that from the output port was 6% separately. The average traffic rate on the overall ATM backbone showed around 1 %.From the result, we concluded that the newly constructed network had such an enough capability supporting hospital information system without any interruption. Furthermore, we expect that it will be sufficient to support the additional traffic increment by PACS and group ware applications.

A modulation method for the data transmission of the telemedicine system / 医疗卫生装备

Telemedicine is the significant object of the medicine in the future. This paper introduces an available counteractive mechanism which is derived from the orthogonal Latin squares, and a modulation method for the data transmission of the telemedicine system is proposed. This method could resolve the problem of overlapping interference from multiple accesses on one channel efficiently. At the same time, it also has potential advantages in increasing the user numbers in one channel and improving the channel utilization.