Corrigendum to "Cartesian Control of Sit-to-Stand Motion Using Head Position Feedback".

[This corrects the article DOI: 10.1155/2020/1979342.].

Cartesian Control of Sit-to-Stand Motion Using Head Position Feedback.

Sit-to-stand (STS) motion is an indicator of an individual's physical independence and well-being. Determination of various variables that contribute to the execution and control of STS motion is an active area of research. In this study, we evaluate the clinical hypothesis that besides numerous other factors, the central nervous system (CNS) controls STS motion by tracking a prelearned head position trajectory. Motivated by the evidence for a task-oriented encoding of motion by the CNS, we adopt a robotic approach for the synthesis of STS motion and propose this scheme as a solution to this hypothesis. We propose an analytical biomechanical human CNS modeling framework where the head position trajectory defines the high-level task control variable. The motion control is divided into low-level task generation and motor execution phases. We model CNS as STS controller and its Estimator subsystem plans joint trajectories to perform the low-level task. The motor execution is done through the Cartesian controller subsystem that generates torque commands to the joints. We do extensive motion and force capture experiments on human subjects to validate our analytical modeling scheme. We first scale our biomechanical model to match the anthropometry of the subjects. We do dynamic motion reconstruction through the control of simulated custom human CNS models to follow the captured head position trajectories in real time. We perform kinematic and kinetic analyses and comparison of experimental and simulated motions. For head position trajectories, root mean square (RMS) errors are 0.0118 m in horizontal and 0.0315 m in vertical directions. Errors in angle estimates are 0.55 rad, 0.93 rad, 0.59 rad, and 0.0442 rad for ankle, knee, hip, and head orientation, respectively. RMS error of ground reaction force (GRF) is 50.26 N, and the correlation between ground reaction torque and the support moment is 0.72. Low errors in our results validate (1) the reliability of motion/force capture methods and anthropometric technique for customization of human models and (2) high-level task control framework and human CNS modeling as a solution to the hypothesis. Accurate modeling and detailed understanding of human motion can have significant scope in the fields of rehabilitation, humanoid robotics, and virtual characters' motion planning based on high-level task control schemes.

Gender differences in weight status and misperception patterns among university students: A cross sectional study.

Perceived body weight is a better predictor of weight management behaviour than actual weight of a person. We conducted a cross sectional study to examine the prevalence of weight status and investigate gender difference between actual and perceived body weight among the students of Bahaudin Zakariya University, Multan Pakistan. Data was collected from 475 students. Height and weight were measured and weight status defined according to WHO criterion for Asian populations. Weight perception was assessed by short interviews. Chi square test was used to analyze difference by gender and through various BMI groups. Incidence of underweight, overweight and obesity remained 11.3%, 14.6% and 14% among boys and 24.6%, 11.3% and 14.15% among girls respectively (P <0.001). About one third (31.7%) of the participants misclassified themselves. The most accurate estimation (76.9%) was encountered in overweight. (P value= 0.00001). Measured weight status and weight perception differed significantly between male and female students (P <0.05).

Influence of free drug samples on prescribing by physicians: A cross sectional survey.

Free drug samples are distributed among doctors as a promotional tool. We investigated the effects of dispensing samples on prescriptions by the doctors and their opinion about samples through a cross-sectional survey. A questionnaire was distributed among the doctors in the Department of Medicine, Nishtar Hospital Multan. It contained drug choices for two hypothetical scenarios, options and reasons for using free samples and doctors' views about them. Response rate remained 83% (166/198). In scenario 1 (rheumatoid arthritis), 100 % and in scenario 2 (acid peptic disease), 13% of sample users dispensed against their preference while in both cases 78 % prescribed the same brand afterwards. Trainees used samples more frequently in both vignettes (p value 0.24 and 0.001 respectively). Mainly, samples were used as a cost-effective measure and were considered a source of medication for poor, significantly. (p value 0.007). But in this process, physicians ignored their first choice and inadvertently increased the total expenditure.