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A non-periodic oscillatory behavior of the unscented Kalman filter (UKF) when used to filter noisy contaminated chaotic signals is reported. We show both theoretically and experimentally that the gain of the UKF may not converge or diverge but oscillate aperiodically. More precisely, when a nonlinear system is periodic, the Kalman gain and error covariance of the UKF converge to zero. However, when the system being considered is chaotic, the Kalman gain either converges to a fixed point with a magnitude larger than zero or oscillates aperiodically. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether low-intensity ergometer aerobic training has beneficial effect on glucose tolerance in nondiabetic patients with severely impaired stroke. Methods: Fifty-four severely impaired stroke survivors were recruited and randomly assigned to the experimental group and control group. They have no diabetes history with fasting plasma glucose less than 7 mmol/L. Both groups participated in a 6-week rehabilitation training program with low-intensity ergometer aerobic training added only in the experimental group 3 times per week. Primary outcome variables were fasting glucose, fasting insulin, 2-hour glucose, and homeostasis model assessment–insulin resistance (HOMA-IR) in oral glucose tolerance test before and after intervention. Results: Before intervention, 36 of 54 (66.7%) were diagnosed with impaired glucose status or diabetic glucose tolerance totally. The average 2-hour plasma glucose level was 9.14 ± 1.39 mmol/L. After intervention, aerobic training significantly improved fasting insulin (from 8.51 ± 2.01 μU/mL to 7.11 ± 2.02 μU/mL), 2-hour glucose level (from 9.13 ± 1.14 mmol/L to 7.22 ± 1.23 mmol/L), and HOMA-IR (from 1.62 ± 1.01 to 1.29 ± .79) in the intervention group compared with the control group (P < .05). Aerobic training also significantly improved their glucose tolerance state (P < .05). Conclusions: Preliminary findings suggest that abnormal glucose tolerance may be highly present among severely impaired nondiabetic stroke patients and low-intensity ergometer aerobic training may have beneficial role in improving glucose tolerance. [Copyright &y& Elsevier]