Visuomotor Adaptation Without Vision?

In 1995, an aftereffect following treadmill running was described, in which people would inadvertently advance when attempting to run in place on solid ground with their eyes closed. Although originally induced from treadmill running, the running-in-place aftereffect is argued here to result from the absence of sensory information specifying advancement during running. In a series of experiments in which visual information was systematically manipulated, aftereffect strength (AE), measured as the proportional increase (post-test/pre-test) in forward drift while attempting to run in place with eyes closed, was found to be inversely related to the amount of geometrically correct optical flow provided during induction. In particular, experiment 1 (n=20) demonstrated that the same aftereffect was not limited to treadmill running, but could also be strongly generated by running behind a golf-cart when the eyes were closed (AE=1.93), but not when the eyes were open (AE=1.16). Conversely, experiment 2 (n=39) showed that simulating an expanding flow field, albeit crudely, during treadmill running was insufficient to eliminate the aftereffect. Reducing ambient auditory information by means of earplugs increased the total distances inadvertently advanced while attempting to run in one place by a factor of two, both before and after adaptation, but did not influence the ratio of change produced by adaptation. It is concluded that the running-in-place aftereffect may result from a recalibration of visuomotor control systems that takes place even in the absence of visual input

The Perceptual Experience Of Slope By Foot And By Finger

Historically, the bodily senses have often been regarded as impeccable sources of spatial information and as being the teacher of vision. Here, the authors report that the haptic perception of slope by means of the foot is greatly exaggerated. The exaggeration is present in verbal as well as proprioceptive judgments. It is shown that this misperception of pedal slope is not caused by calibration to the well-established visual misperception of slope because it is present in congenitally blind individuals as well. The pedal misperception of slope is contrasted with the perception of slope by dynamic touch with a finger in a force-feedback device. Although slopes feel slightly exaggerated even when explored by finger, they tend to show much less exaggeration than when equivalent slopes are stood on. The results are discussed in terms of a theory of coding efficiency. (PsycINFO Database Record (c) 2013 APA, all rights reserved)(journal abstract

Adaptation To Conflicting Visual And Physical Heading Directions During Walking

We investigated the role of global optic flow for visual–motor adaptation of walking direction. In an immersive virtual environment, observers walked to a circular target lying on either a homogeneous ground plane (target-motion condition) or a textured ground plane (ground-flow condition). During adaptation trials, we changed the mapping from physical to visual space to create a conflict between physical and visual heading directions. On these trials, the visual heading specified by optic flow deviated from an observer\u27s physical heading by ±10°. This conflict was not noticed by observers but caused them to walk along curved paths to the target. Over the course of 20 adaptation trials, observers adapted to partially compensate for the conflicts, resulting in straighter paths. When the conflicts were removed post-adaptation, observers showed aftereffects in the opposite direction. The amount of adaptation was similar for target-motion and ground-flow conditions (20–25%), with the ground-flow environment producing slightly faster adaptation and larger aftereffects. We conclude that the visual–motor system can rapidly recalibrate the mapping from physical to visual heading and that this adaptation does not strongly depend on full-field optic flow

The Underestimation Of Egocentric Distance: Evidence From Frontal Matching Tasks

There is controversy over the existence, nature, and cause of error in egocentric distance judgments. One proposal is that the systematic biases often found in explicit judgments of egocentric distance along the ground may be related to recently observed biases in the perceived declination of gaze (Durgin & Li, Attention, Perception, & Psychophysics, in press), To measure perceived egocentric distance nonverbally, observers in a field were asked to position themselves so that their distance from one of two experimenters was equal to the frontal distance between the experimenters. Observers placed themselves too far away, consistent with egocentric distance underestimation. A similar experiment was conducted with vertical frontal extents. Both experiments were replicated in panoramic virtual reality. Perceived egocentric distance was quantitatively consistent with angular bias in perceived gaze declination (1.5 gain). Finally, an exocentric distance-matching task was contrasted with a variant of the egocentric matching task. The egocentric matching data approximate a constant compression of perceived egocentric distance with a power function exponent of nearly 1; exocentric matches had an exponent of about 0.67. The divergent pattern between egocentric and exocentric matches suggests that they depend on different visual cues

Redesigning Engineering Education

In developing the PLAN, WPI sought to address concerns inherent to its then traditional curriculum that was rigid, unresponsive to differences among students, and was compartmentalized by independent departments so that intellectual growth was fragmented. The PLAN was an entirely new and different educational program responsive to the needs of students and society while nurturing sensitivity to the ideas and values of our society. It included fundamental departures from the traditional elements of technical education including: A. The achievement of competence rather than the accumulation of credits. B. Individual freedom and responsibility in planning the program of study. C. A large component of project and independent study learning. D. Emphasis on education as a cooperative venture between faculty and students. Frequently, changes to engineering curricula involve the addition of new material to a well-established body of knowledge. Deciding which components to eliminate becomes the central issue in curricula reform. To adopt and implement the PLAN, the WPI community necessarily employed a more fundamental approach by focusing on learning rather than information transfer. Additionally, the PLAN has been a dynamic entity undergoing continual and substantive revision in the best spirit of continuous improvement. In the following sections the processes invoked in the adoption and revision of the PLAN by the WPI community are outlined in the hope they may help guide other faculties in embracing substantive revision

Ultrasonic Technique for Investigation of the Effect of Grid-Generated Turbulence on Sound Wave Propagation

This paper concerns an experimental study of the effects of the grid-generated turbulence on the propagation of acoustical waves in a wind tunnel. Turbulence effects are investigated using ultrasound time-of-flight method, employing counter-propagating ultrasonic pulses. Turbulence effects are an important source of error in the active probing of the atmosphere using sound sources. The emphasis is on the propagation time fluctuations and their interpretation using theoretical analysis of Kolmogorov

Effect of Chaos and Stochastics Induced By Internal Waves on Acoustic Wave Propagation

In the present paper the eikonal equation is considered in the form of a second order, nonlinear ordinary differential equation with harmonic excitation due to internal wave. The harmonic excitation is taken imperfect, i.e. there is a random phase modulation due to Gaussian white noise. The amplitude and wavelength of the acoustic wave are used as the principle signal characteristics in bifurcation analysis. The regions of instability, identified using the bifurcation diagrams, examined through phase diagrams and Poincare maps. The effect of stochastic nature in addition to chaotic one of internal waves is demonstrated by means of comparison of the numerical data obtained for perfectly periodic excitation. Preliminary analysis shows very strong dependence on noise intensity at some values of amplitude and wave length of internal wave

Channel Capacities for Different Antenna Arrays with Various Transmitting Angles in Tunnels

[[abstract]]This paper focuses on the research of channel capacity of multiple-input multipleoutput (MIMO) system with different transmitting angles in straight and curvy tunnels.Araytracing technique is developed to calculate channel frequency responses for tunnels, and the channel frequency response is further used to calculate corresponding channel capacity. The channel capacities are calculated based on the realistic environment. The channel capacities of MIMO long term evolution system using spatial and polar antenna arrays by different transmitting angles are computed. Numerical results show that, The channel capacity for transmitting angle at 15◦ is largest compared to the other angles in the tunnels. Moreover, the channel capacity of polar array is better than that of spatial array both in the straight and curvy tunnels. Besides, the channel capacity for the tunnels with traffic is larger than that without traffic. Finally, it isworth noting that in these cases the presentwork provides not only comparative information but also quantitative information on the performance reduction.[[notice]]補正完畢[[incitationindex]]SC

Vitamin A requirements of growing chicks, Bulletin, no. 310

The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire

Using giant african pouched rats to detect human tuberculosis: a review

Despite its characteristically low sensitivity, sputum smear microscopy remains the standard for diagnosing tuberculosis (TB) in resource-poor countries. In an attempt to develop an alternative or adjunct to microscopy, researchers have recently examined the ability of pouched rats to detect TB-positive human sputum samples and the microbiological variables that affect their detection. Ten published studies, reviewed herein, suggest that the rats are able to detect the specific odor of Mycobacterium tuberculosis, which causes TB, and can substantially increase new-case detections when used for second-line TB screening following microscopy. Further research is needed to ascertain the rats' ability to detect TB in children and in HIV-positive patients, to detect TB when used for first-line screening, and to be useful in broad-scale applications where cost effectiveness is a major consideration