scholarly journals Sensorimotor impairment from a new analog of spaceflight-altered neurovestibular cues

2020 ◽  
Vol 123 (1) ◽  
pp. 209-223
Author(s):  
Jordan B. Dixon ◽  
Torin K. Clark
Keyword(s):  
Head Tilt ◽  
Semicircular Canals ◽  
Control Groups ◽  
Head Restraint ◽  
The Subject ◽  
Sensorimotor Impairment ◽  
Self Motion ◽  
Future Work ◽  
Extended Exposure ◽  
Sensorimotor Performance

Exposure to microgravity during spaceflight causes central reinterpretations of orientation sensory cues in astronauts, leading to sensorimotor impairment upon return to Earth. Currently there is no ground-based analog for the neurovestibular system relevant to spaceflight. We propose such an analog, which we term the “wheelchair head-immobilization paradigm” (WHIP). Subjects lie on their side on a bed fixed to a modified electric wheelchair, with their head restrained by a custom facemask. WHIP prevents any head tilt relative to gravity, which normally produces coupled stimulation to the otoliths and semicircular canals, but does not occur in microgravity. Decoupled stimulation is produced through translation and rotation on the wheelchair by the subject using a joystick. Following 12 h of WHIP exposure, subjects systematically felt illusory sensations of self-motion when making head tilts and had significant decrements in balance and locomotion function using tasks similar to those assessed in astronauts postspaceflight. These effects were not observed in our control groups without head restraint, suggesting the altered neurovestibular stimulation patterns experienced in WHIP lead to relevant central reinterpretations. We conclude by discussing the findings in light of postspaceflight sensorimotor impairment, WHIP’s uses beyond a spaceflight analog, limitations, and future work. NEW & NOTEWORTHY We propose, implement, and demonstrate the feasibility of a new analog for spaceflight-altered neurovestibular stimulation. Following extended exposure to the analog, we found subjects reported illusory self-motion perception. Furthermore, they demonstrated decrements in balance and locomotion, using tasks similar to those used to assess astronaut sensorimotor performance postspaceflight.

THE EFFECT OF APPLYING DEMONSTRATION METHOD ON STUDENTS’ ACHIEVEMENT IN SPEAKING SKILL AT THE THIRD GRADE OF SMK PAB 3 MEDAN ESTATE

2015 ◽  
Vol 4 (2) ◽  
Author(s):  
Meryanti Napitupulu And Anni Holila Pulungan
Keyword(s):  
High School ◽  
Control Group ◽  
Vocational High School ◽  
Control Groups ◽  
Speaking Test ◽  
The Third ◽  
Speaking Skill ◽  
The Subject ◽  
And Control ◽  
Experimental Group

This study was conducted as an attempt to discover the effect of applying Demonstration Method on students’ achievement in speaking skill. It was an experimental research. The subject was students of Grade XII, Vocational High School (Sekolah Menengah Kejuruan: SMK), which consisted of 79 students. The research was divided into two groups: experimental and control groups. The instrument used to collect the data was speaking test. To obtain the reliability of the test, the writer applied Kuder Richardson 21 formula. The result of the reliability was 0.7, and it was found that the test was reliable. The data were analyzed by using t-test formula. The analysis showed that the scores of the students in the experimental group were significantly higher than the scores of the students in the control group at the level of significant m = 0.05 with the degree of freedom (df) 77, t-observed value 8.9 > t-table value 1.99. The findings indicate that using Demonstration Method significantly affected the students’ achievement in speaking skill. So, English teachers are suggested to use Demonstration Method in order to improve students’ achievement in speaking skill.

Impacts of Rotation Axis and Frequency on Vestibular Perceptual Thresholds

2022 ◽  
pp. 1-29
Author(s):  
Andrew R. Wagner ◽  
Megan J. Kobel ◽  
Daniel M. Merfeld
Keyword(s):  
Multisensory Integration ◽  
Rotation Axis ◽  
Semicircular Canals ◽  
Rotation Velocity ◽  
Pass Filter ◽  
Motion Cues ◽  
Left Posterior ◽  
Rotation Plane ◽  
Self Motion ◽  
Lower Frequencies

Abstract In an effort to characterize the factors influencing the perception of self-motion rotational cues, vestibular self-motion perceptual thresholds were measured in 14 subjects for rotations in the roll and pitch planes, as well as in the planes aligned with the anatomic orientation of the vertical semicircular canals (i.e., left anterior, right posterior; LARP, and right anterior, left posterior; RALP). To determine the multisensory influence of concurrent otolith cues, within each plane of motion, thresholds were measured at four discrete frequencies for rotations about earth-horizontal (i.e., tilts; EH) and earth-vertical axes (i.e., head positioned in the plane of the rotation; EV). We found that the perception of rotations, stimulating primarily the vertical canals, was consistent with the behavior of a high-pass filter for all planes of motion, with velocity thresholds increasing at lower frequencies of rotation. In contrast, tilt (i.e, EH rotation) velocity thresholds, stimulating both the canals and otoliths (i.e., multisensory integration), decreased at lower frequencies and were significantly lower than earth-vertical rotation thresholds at each frequency below 2 Hz. These data suggest that multisensory integration of otolithic gravity cues with semicircular canal rotation cues enhances perceptual precision for tilt motions at frequencies below 2 Hz. We also showed that rotation thresholds, at least partially, were dependent on the orientation of the rotation plane relative to the anatomical alignment of the vertical canals. Collectively these data provide the first comprehensive report of how frequency and axis of rotation influence perception of rotational self-motion cues stimulating the vertical canals.

Perceived self-motion in two visual contexts: Dissociable mechanisms underlie perception

2006 ◽  
Vol 16 (1-2) ◽  
pp. 23-28 ◽  
Author(s):  
W. Geoffrey Wright ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Motion Perception ◽  
Path Integration ◽  
Visual Input ◽  
Visual Scene ◽  
Spatial Context ◽  
Immersive Virtual Environment ◽  
Physical Context ◽  
The Subject ◽  
Self Motion ◽  
Visual Acceleration

We evaluated the influence of moving visual scenes and knowledge of spatial and physical context on visually induced self-motion perception in an immersive virtual environment. A sinusoidal, vertically oscillating visual stimulus induced perceptions of self-motion that matched changes in visual acceleration. Subjects reported peaks of perceived self-motion in synchrony with peaks of visual acceleration and opposite in direction to visual scene motion. Spatial context was manipulated by testing subjects in the environment that matched the room in the visual scene or by testing them in a separate chamber. Physical context was manipulated by testing the subject while seated in a stable, earth-fixed desk chair or in an apparatus capable of large linear motions, however, in both conditions no actual motion occurred. The compellingness of perceived self-motion was increased significantly when the spatial context matched the visual input and actual body displacement was possible, however, the latency and amplitude of perceived self-motion were unaffected by the spatial or physical context. We propose that two dissociable processes are involved in self-motion perception: one process, primarily driven by visual input, affects vection latency and path integration, the other process, receiving cognitive input, drives the compellingness of perceived self-motion.

Sensorimotor aspects of high-speed artificial gravity: II. The effect of head position on illusory self motion

2003 ◽  
Vol 12 (5-6) ◽  
pp. 283-289
Author(s):  
Fred W. Mast ◽  
Nathaniel J. Newby ◽  
Laurence R. Young
Keyword(s):  
Healthy Subjects ◽  
Horizontal Plane ◽  
High Speed ◽  
Semicircular Canals ◽  
Vertical Axis ◽  
Head Position ◽  
Artificial Gravity ◽  
Axis Of Rotation ◽  
Self Motion

The effects of cross-coupled stimuli on the semicircular canals are shown to be influenced by the position of the subject's head with respect to gravity and the axis of rotation, but not by the subject's head position relative to the trunk. Seventeen healthy subjects made head yaw movements out of the horizontal plane while lying on a horizontal platform (MIT short radius centrifuge) rotating at 23 rpm about an earth-vertical axis. The subjects reported the magnitude and duration of the illusory pitch or roll sensations elicited by the cross-coupled rotational stimuli acting on the semicircular canals. The results suggest an influence of head position relative to gravity. The magnitude estimation is higher and the sensation decays more slowly when the head's final position is toward nose-up (gravity in the subject's head x-z-plane) compared to when the head is turned toward the side (gravity in the subject's head y-z-plane). The results are discussed with respect to artificial gravity in space and the possible role of pre-adaptation to cross-coupled angular accelerations on earth.

SELECTIVE AUDIO-VISUAL INSTRUCTION FOR MENTALLY RETARDED PUPILS, Edward Goldstein. Springfield, Ill.: Charles C Thomas, 1964, 96 pp., $5.25

PEDIATRICS ◽  
1964 ◽  
Vol 34 (2) ◽  
pp. 282-282
Author(s):  
Randolph K. Byers
Keyword(s):  
Motion Pictures ◽  
Mentally Retarded ◽  
Food Preparation ◽  
Control Groups ◽  
Visual Instruction ◽  
Commercial Use ◽  
The Subject ◽  
Mentally Retarded Children ◽  
Special Classes

This little book is primarily educationally oriented. It does, however, provide a very useful review of the subject of education of mentally retarded children and the theories underlying it. It also reviews the subject of the development of motion pictures in relation to commercial use and in education. Finally, it records an experiment conducted among three experimental and two control groups of children in special classes in relation to learning about the process of food preparation and service.

A Program for an Investigation of the Rudder-Torque Problem

1965 ◽  
Vol 2 (03) ◽  
pp. 282-298
Author(s):  
Karl E. Schoenherr
Keyword(s):  
Research Program ◽  
Current Knowledge ◽  
Lateral Force ◽  
The Status ◽  
The Subject ◽  
Future Work ◽  
Marine Engineers

Panel H-10 (Controllability) of The Society of Naval Architects and Marine Engineers Technical and Research Program was requested to undertake an investigation of existing uncertainties in pre-calculating rudder torque and lateral force. In order to become quickly familiar with the subject and prospects therein, the Panel commissioned the author of this paper to survey the status of current knowledge of the subject and prepare a report of the findings. In particular, this report was to identify the most promising approaches for future work leading to an ultimate solution of the problem and to include technical descriptions of proposed programs for an exhaustive investigation, all of which are discussed in this paper.

Lax and Dense-Eared Wheats

1914 ◽  
Vol 6 (3) ◽  
pp. 371-386
Author(s):  
W. H. Parker
Keyword(s):  
Quantitative Character ◽  
General Importance ◽  
External Conditions ◽  
The Subject ◽  
Future Work

The present paper is written with no pretence at finality, and consequently some excuse is due for its publication at the present time. The author was induced to write it since the results so far obtained by him do not seem to agree, in all points, with the work previously done on the subject, and tend to show that there is much scope for future work both on this matter and also on a matter of much greater general importance, namely, on the influence of external conditions on a quantitative character.

scholarly journals Mid-Cretaceous acanthomorph fishes with the description of a new species from the Turonian of Lac des Bois, Northwest Territories, Canada

2016 ◽  
Vol 1 ◽  
pp. 101 ◽  
Author(s):  
Alison M Murray
Keyword(s):  
Northwest Territories ◽  
Neural Spine ◽  
Single Specimen ◽  
Western Interior Seaway ◽  
Incertae Sedis ◽  
Comprehensive Survey ◽  
The Subject ◽  
Future Work ◽  
A New Species ◽  
Cretaceous Deposits

A single specimen of a new acanthomorph fish is described from a Turonian locality sampling the northern part of the Cretaceous Western Interior Seaway. This brings to three the number of acanthomorphs from Lac des Bois, Northwest Territories, Canada. The previously named acanthomorph, Boreiohydrias dayi (Boriohydriidae), was placed in the Polymixiiformes. The second, represented by a poorly preserved fish, was left unnamed and incertae sedis in Acanthomorpha. The new one described here, Cumbaaichthys oxyrhynchus gen. et sp. nov. cannot be easily placed in any previously described families. This fish is placed in the Polymixiiformes based on the caudal skeleton having 18 principal rays (16 branched), and having a full neural spine on the second preural centrum. Polymixiiform relationships are not well established but they are the subject of several current studies; therefore, the new acanthomorph is placed incertae sedis within this order but with the understanding that this placement may be refined with future work. Previous studies have suggested that acanthomorphs may have flourished with warming climates of the Cenomanian–Turonian. A comprehensive survey of named acanthomorphs from mid-Cretaceous deposits shows there are more species known from the Cenomanian rather than the Turonian, although this may be biased by the age of known fossiliferous deposits.

Application of Satellite Based Augmentation Systems to Altitude Separation

1999 ◽  
Vol 52 (3) ◽  
pp. 313-317
Author(s):  
Jean Pierre Magny
Keyword(s):  
Design Principles ◽  
Preliminary Design ◽  
Vertical Separation ◽  
Safety Issues ◽  
The Subject ◽  
Future Work

This paper presents the application of GNSS1, or more precisely of Satellite Based Augmentation Systems (SBAS), to vertical separation for en-route, approach and landing operations. Potential improvements in terms of operational benefit and of safety are described for two main applications. First, vertical separation between en-route aircraft, which requires a system available across wide areas. SBAS (EGNOS, WAAS, and MSAS) are very well suited for this purpose before GNSS2 becomes available. And secondly, vertical separation from the ground during approach and landing, for which preliminary design principles of instrument approach procedures and safety issues are presented. Approach and landing phases are the subject of discussions within ICAO GNSS-P. En-route phases have been listed as GNSS-P future work and by RTCA for development of new equipments.

II. Bishop Wren and the Suppression of the Norwich Lecturers

1968 ◽  
Vol 11 (2) ◽  
pp. 237-254 ◽  
Author(s):  
Peter King
Keyword(s):  
Rapid Growth ◽  
Religious Organizations ◽  
The Subject ◽  
Future Work

One of the most serious problems facing Archbishop Laud was the rapid growth of the Lecturer Movement during the 1620s and 1630s. The increasing numbers of graduates available, and the increasing amount of money donated to support them meant that the weekly lectures had become one of the chief “religious … organizations of the opposition”, and were beginning to “undermine the hierarchical principle”. The gravity of the situation was marked by the increasingly stringent regulation of the lecturers. They had originally been allowed to preach with very little control, but from the Canons of 1604 onwards they were made the subject of several new regulations. These culminated in the Directions of March 16296 which, although issued by Archbishop Abbot, were based upon suggestions made by Laud to the king. Soon afterwards the lecturers in London Diocese were curtailed as a prelude to Laud's future work as archbishop. The Directions were reissued in January 1634, and a policy of deliberately reducing certain kinds of lecturer was initiated in several dioceses, pursued in the Metropolitical Visitation, and completed by Laud's supporters amongst the bishops.

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