Altered gravity environments, such as those experienced by astronauts, impact spatial orientation perception, and can lead to spatial disorientation and sensorimotor impairment. To more fully understand and quantify the impact of altered gravity on orientation perception, several mathematical models have been proposed. The utricular shear, tangent, and the idiotropic vector models aim to predic...

The aim of this study was to compare the thoracic and lumbar curvatures and pelvic tilt in relaxed standing and maximal trunk flexion among highlytrained young athletes from three different sports disciplines. Thirty-two male canoeists, 30 male kayakers and 24 male tennis players were recruited for the study. The Spinal Mouse® system was used to measure the thoracic and lumbar sagittal spinal c...

The control of upper body (UB) orientation relative to the pelvis in the frontal plane was characterized by analyzing responses to external perturbations consisting of continuous pelvis tilts (eyes open [EO] and eyes closed [EC]) and visual surround tilts (EO) at various amplitudes. Lateral sway of the lower body was prevented on all tests. UB sway was analyzed by calculating impulse-response f...

We measured the ability to report the tilt (direction of maximal slope) of a plane under monocular viewing conditions, from static depth cues (square grid patterns) and motion parallax (small rotations of the plane about a frontoparallel axis). These two cues were presented separately, or simultaneously. In the latter case they specified tilts that were either collinear (coherent case) or ortho...

Since humans are under ceaseless orthostatic stress, the mechanisms to maintain arterial pressure (AP) against gravitational fluid shift are important. As one mechanism, it was reported that upright tilt reset baroreflex control of renal sympathetic nerve activity (SNA) to a higher SNA in anesthetized rabbits. In the present study, we tested the hypothesis that upright tilt causes a parallel re...

Current interaction techniques for mobile map-based applications suffer from several usability problems. Tilt interaction provides an alternative form of interaction which combines the benefits of one handed interaction with intuitive physical gestures. Research has shown that tilt interaction suffers from a lack of controllability, high mental demand and practical concerns. In this paper, the ...

[Purpose] The purpose of this paper is to report the effect of individual strengthening exercises for the anterior pelvic tilt muscles on back pain, pelvic tilt angle, and lumbar ROM of a low back pain (LBP) patient with flat back. [Subject] A 37 year-old male, who complained of LBP pain at L3-5 levels with flat back, participated. [Methods] He performed the individual strengthening exercises f...

The paper is devoted to the study of tilt-stable local minimizers of general optimization problems in finite-dimensional spaces and its applications to classical nonlinear programs with twice continuously differentiable data. The importance of tilt stability has been well recognized from both theoretical and numerical aspects of optimization, and this notion has been extensively studied in the ...

BACKGROUND Head-down tilt is often used to assist cannulation of the internal jugular vein (IJV). However, the optimal duration of tilt before cannulation is not well defined. METHODS Fifteen healthy volunteers were studied by B-mode duplex sonography to assess changes in cross-sectional area (CSA) of the right IJV during 10 degrees head-down tilt. RESULTS Median CSA in the supine position ...

In this paper we give, for the first time, a complete description of the dynamics of tilted spatially homogeneous cosmologies of Bianchi type II. The source is assumed to be a perfect fluid with equation of state p = (γ − 1)µ, where γ is a constant. We show that unless the perfect fluid is stiff, the tilt destabilizes the Kasner solutions, leading to a Mixmaster-like initial singularity, with t...