This paper is concerned with a class of time-optimal control problems for the swing and the ski. We first consider the motion of a man standing on a swing. For simplicity, we neglect friction and air resistance and assume that the mass of the swinger is concentrated in his baricenter B. Let θ be the angle formed by the swing and the downward vertical direction and r the radius of oscillation, i...

To win elections, candidates attempt to mobilize supporters and persuade swing voters. With what magnitude each operates across American elections is not clear. I argue that the influence of swing voters should depend upon change in the candidates across elections and that the consequences of changes in composition should depend upon the relative balance of campaign expenditures. I estimate a B...

ing from what seem to be the transitory phenomena, like the post-Communist and East Asian crises, we seem to be in the presence of an interesting situation where world inequality is driven by what happens to the relative incomes of the three large areas: (1) the rich countries of the West, (2) urban incomes in China and India, and (3) rural incomes in these two countries. The ratio between (2) ...

Computerized posturography systems are commonly used to evaluate postural equilibrium and balance, usually performing a static balance test in which the person being tested tries to minimize the sway of the body. Most variations of static test are part of the modified Clinical Test of Sensor Integration in Balance (mCTSIB) test protocol. Given its importance in clinical practice, a recurrent qu...

We recommend the thesis prepared under our supervision by The integration of visual, vestibular, and somatosensory components are used to maintain one's postural balance. Postural control changes over time and body sway increases with age. The different sensory systems begin to develop and refine starting when children are young, while in older adults it begins to decline. Hence, it is importan...

conclusions examining postural control as an endophenotype or early diagnostic marker of autism is a conceptual premise which should be considered in future investigations. at the end of the review, methodological recommendations on the assessment of postural control have also been provided. results individuals with asd have problems in maintaining postural control in infancy that well persists...

Children with cerebral palsy often walk with diminished knee extension during the terminal-swing phase, resulting in a troublesome "crouched" posture at initial contact and a shortened stride. Treatment of this gait abnormality is challenging because the factors that extend the knee during normal walking are not well understood, and because the potential of individual muscles to limit terminal-...

Background: Poor balance performance and impaired postural control have been frequently reported in patients with low back pain. However, postural control is rarely monitored during the course of treatment even though poor postural control may contribute to chronicity and recurrence of symptoms. Therefore, the present study aimed at investigating the effect of a nonextensible lumbosacral orth...

To gain insight into the neural mechanisms controlling different forms of quadrupedal walking of normal cats, data on postural orientation, hindlimb kinematics, and motor patterns of selected hindlimb muscles were assessed for four grades of upslope walking, from 25 to 100% (45 degrees incline), and compared with similar data for level treadmill walking (0.6 m/s). Kinematic data for the hip, kn...