Postural Instability and Seasickness in a Motion-Based Shooting Simulation

2020 ◽  
Vol 91 (9) ◽  
pp. 703-709
Author(s):  
Kyle A. Pettijohn ◽  
Dominick V. Pistone ◽  
Andrew L. Warner ◽  
Grant J. Roush ◽  
Adam T. Biggs
Keyword(s):  
Motion Sickness ◽  
Military Personnel ◽  
Postural Instability ◽  
The Other ◽  
Free Condition ◽  
Life And Death ◽  
Instability Theory ◽  
Fixed Condition ◽  
Moving Platform ◽  
Motion Profile

BACKGROUND: Motion sickness is a problem for many; however, it is especially pressing for military personnel who need to operate in life and death environments. The current study investigated the underlying cause of motion sickness by testing postural instability theory.METHODS: Subjects experienced realistic motion profiles while performing a virtual reality shooting task and reporting any motion sickness symptoms. Postural instability was manipulated within 20 subjects across 2 conditions. In one condition, subjects could readily adapt their posture to the motion profile by adjusting their feet on the platform (Free), and in the other condition, their feet were fixed in place on the moving platform (Fixed). This Free condition decreased postural instability by allowing adjustment, while the Fixed condition increased postural instability by restricting adjustment. The same subjects completed both conditions to control for individual differences in motion sickness susceptibility.RESULTS: Overall, motion sickness was mild as measured by SSQ (M 14.41, Free; M 18.89, Fixed), and no statistically significant differences were observed between the conditions. Performance on the shooting task was reduced in accuracy by approximately 40%, although this result did not differ between conditions.DISCUSSION: The results do not support postural instability as a contributing factor in motion sickness symptomology. They also demonstrate the importance of accounting for motion when conducting training.Pettijohn KA, Pistone DV, Warner AL, Roush GJ, Biggs AT. Postural instability and seasickness in a motion-based shooting simulation. Aerosp Med Hum Perform. 2020; 91(9):703709.

The Parallel Mechanism and Variable Acceleration Control Method

2013 ◽  
Vol 579-580 ◽  
pp. 659-664
Author(s):  
Xiang Bo Ouyang ◽  
Ke Tian Li ◽  
Hong Jian Xia ◽  
Su Juan Wang ◽  
Huan Wei Zhou ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Control Method ◽  
The Other ◽  
Connecting Rod ◽  
Motion Platform ◽  
The Third ◽  
Symmetric Structure ◽  
Slide Block ◽  
Operation Process ◽  
Moving Platform

t presents the parallel mechanism and variable acceleration control method, which is composed of slider, connecting rod, moving platform and linear guide etc. The motion platform is supported by three connecting rods through hinging, the other end of the connecting rods are respectively hinged with two sliders. Among them two pairs of connecting rod, two sliders and the moving platform formed a symmetric structure that is the so called Parallel Mechanism. The third connecting rod is parallel to one of two connecting rods, so that the two parallel connecting rods, slide block and the moving platform formed a parallelogram structure, it makes that the moving platform is always parallel to liner guiderail in the process of movement. By controlling the two sliders moving in the way of variable acceleration, it can make the trajectory curve, speed curve and acceleration curve of the moving platform are continuous, smooth, so impact and vibration of the moving platform is limited in the operation process.

Ein föderales Imperium?

2021 ◽  
Author(s):  
Patrick Rummel
Keyword(s):  
South Africa ◽  
New Zealand ◽  
Great Britain ◽  
British Empire ◽  
19Th Century ◽  
Military Personnel ◽  
The Other ◽  
The 19Th Century

The previously ignored model of Greek colonisation attracted numerous actors from the 19th century British empire: historians, politicians, administrators, military personnel, journalists or anonymous commentators used the ancient paradigm to advocate a global federation exclusively encompassing Great Britain and the settler colonies in Canada, Australia, New Zealand and South Africa. Unlike other historical templates, Greek colonisation could be viewed as innovative and unspent: innovative because of the possibility of combining empire and liberty and unspent due to its very novelty, which did not contain the ‘imperial vice’ the other models had so often shown and which had always led to their political and cultural decline.

scholarly journals Van wie zegt de profeet dit? Een een-voudige vraag en een meervoudig antwoord

2005 ◽  
Vol 61 (4) ◽  
Author(s):  
Rein Bos
Keyword(s):  
Old Testament ◽  
The Other ◽  
Biblical Criticism ◽  
Life And Death ◽  
Other Hand ◽  
Christian Perspective ◽  
Practical Theological ◽  
The One ◽  
Christian Congregations ◽  
Single Question

Of whom does the prophet say this? A single question and a multifaceted answerTheologians seeking to preach Old Testament texts meaningful way in Christian congregations face a great challenge. On the one hand, very little has been written in homiletical textbooks about hermeneutical problems facing those who wish to read the Old Testament from the perspective of Christ’s life and death. On the other hand, advances in biblical criticism seemed to have made any such attempt problematic to begin with. In this article, the author attempts to provide a practical-theological contribution to this hermeneutical challenge by reconsidering the heuristic value of mediaeval fourfold interpretation of scriptural passages. By focussing on the servant song of deutero-Isaiah (53) in light of its reinterpretation in Acts 8, this paper aims to provide some suggestions on how Christological interpretation of the Old Testament can be done in a way that takes the original context seriously and is able to read the text from a Christian perspective without the one reading infringing on the other.

scholarly journals Comparable behaviour of ring and little fingers due to an artificial reduction in thumb contribution to hold objects

2020 ◽  
Author(s):  
Banuvathy Rajakumar ◽  
Varadhan SKM
Keyword(s):  
Normal Force ◽  
Safety Margin ◽  
Ring Finger ◽  
Middle Finger ◽  
Human Hand ◽  
Mechanical Advantage ◽  
Free Condition ◽  
Normal Forces ◽  
Fixed Condition ◽  
Little Finger

AbstractBackgroundThe human hand plays a crucial role in accomplishing activities of daily living. The contribution of each finger in the human hand is remarkably unique in establishing object stabilization. According to the mechanical advantage hypothesis, the little finger tends to exert a greater normal force than the ring finger during a supination moment production task to stabilize the object. Similarly, during pronation, the index finger produces more normal force when compared with the middle finger. Hence, the central nervous system employs the peripheral fingers for torque generation to establish the equilibrium as they have a mechanical advantage of longer moment arms for normal force. In our study, we tested whether the mechanical advantage hypothesis is supported in a task in which the contribution of thumb was artificially reduced. We also computed the safety margin of the individual fingers and thumb.MethodologyFifteen participants used five-finger prismatic precision grip to hold a custom-built handle with a vertical railing on the thumb side. A slider platform was placed on the railing such that the thumb sensor could move either up or down. There were two experimental conditions. In the “Fixed” condition, the slider was mechanically fixed, and hence the thumb sensor could not move. In the “Free” condition, the slider platform on which the thumb sensor was placed could freely move. In both conditions, the instruction was to grasp and hold the handle (and the platform) in static equilibrium. We recorded tangential and normal forces of all the fingers.ResultsThe distribution of fingertip forces and moments changed depending on whether the thumb platform was movable (or not). In the free condition, the drop in the tangential force of thumb was counteracted by an increase in the normal force of the ring and little finger. Critically, the normal forces of the ring and little finger were statistically equivalent. The safety margin of the index and middle finger did not show a significant drop in the free condition when compared to fixed condition.ConclusionWe conclude that our results does not support the mechanical advantage hypothesis at least for the specific mechanical task considered in our study. In the free condition, the normal force of little finger was comparable to the normal force of the ring finger. Also, the safety margin of the thumb and ring finger increased to prevent slipping of the thumb platform and to maintain the handle in static equilibrium during the free condition. However, the rise in the safety margin of the ring finger was not compensated by a drop in the safety margin of the index and middle finger.

scholarly journals ‘Between life and death’: On land, silence and liberation in the capital city

2014 ◽  
Vol 70 (1) ◽  
Author(s):  
Stephan F. De Beer
Keyword(s):  
Social Movement ◽  
Mission Statement ◽  
The Other ◽  
Capital City ◽  
Capital Cities ◽  
Life And Death ◽  
University Of Pretoria ◽  
The One ◽  
The University ◽  
The City

This article reflects on the unfinished task of liberation – as expressed in issues of land – and drawing from the work of Franz Fanon and the Durban-based social movement Abahlali baseMjondolo. It locates its reflections in four specific sites of struggle in the City of Tshwane, and against the backdrop of the mission statement of the Faculty of Theology at the University of Pretoria, as well as the Capital Cities Research Project based in the same university. Reflecting on the ‘living death’ of millions of landless people on the one hand, and the privatisation of liberation on the other, it argues that a liberating praxis of engagement remains a necessity in order to break the violent silences that perpetuate exclusion.

Morale Operations and Talking Their Way Into Japan

2021 ◽  
pp. 93-111
Author(s):  
Brian Masaru Hayashi
Keyword(s):  
Asian Americans ◽  
Military Personnel ◽  
Chinese Language ◽  
The Other ◽  
Japanese Military ◽  
Media Communications ◽  
Pictorial Representations ◽  
Chinese Public

The Morale Operations section of the OSS recruited Asian Americans with the requisite skills in media communications. They hired individuals to help with propaganda materials aimed at two targets. One was to the Chinese public, to help stiffen their resolve to resist the Imperial Japanese forces. The other was aimed at the Japanese public and Imperial Japanese military personnel, to weaken their morale and willingness to continue with the war. The means of communication was in print or over the radio. For the former, some were graphic artists and employed to design cartoons and other pictorial representations for those not sufficiently literate in the Chinese language. Others were experienced typesetters and printers. Still others were writers who produced propaganda leaflets that Morale Operations distributed throughout the countryside in China.

If Romeo and Juliet had mobile phones

2013 ◽  
Vol 1 (1) ◽  
pp. 166-171 ◽  
Author(s):  
Barry Wellman ◽  
Lee Rainie
Keyword(s):  
Mobile Phones ◽  
Personal Communication ◽  
The Other ◽  
Romeo And Juliet ◽  
Life And Death ◽  
Location Aware ◽  
The Social ◽  
True Love ◽  
The Difference ◽  
Networked Individualism

How did the absence of mobile phones affect the romantic life and death of Shakespeare’s Romeo and Juliet? The difference in their situation would have been part of the social change to networked individualism from group-based societies. The Mobile Revolution would have afforded personal communication rather than the household-centered communication of the Montagues and the Capulets. Romeo and Juliet would have been always available to each other, instead of wondering where the other might be. Location-aware apps would have plotted their whereabouts. The course of true love would have been more connected.

Segmentary State Formation and the Ritual Control of Water Under the Incas

1993 ◽  
Vol 35 (3) ◽  
pp. 480-514 ◽  
Author(s):  
Peter Gose
Keyword(s):  
The Other ◽  
Political Organization ◽  
The Political ◽  
Political Structure ◽  
Life And Death ◽  
Plant Life ◽  
Kinship Relations ◽  
Human Animal ◽  
The One ◽  
Divine Kingship

There is a strange and unacknowledged paradox in the historiography of the Incas. On the one hand, few would deny that theirs was a typically theocratic archaic state, a divine kingship in which the Inca was thought to.be the son of the Sun. On the other hand, the standard descriptions of Inca political structure barely mention religion and seem to assume a formal separation between state and cult.1I believe that these secularizing accounts are misguided and will show in this essay that the political structure of the pre-Columbian Andes took form primarily around a system of sacred ancestral relics and origin points known generically ashuacas. Each huaca defined a level of political organization that might nest into units of a higher order or subdivide into smaller groupings. Collectively they formed a segmentary hierarchy that transcended the boundaries of local ethnic polities and provided the basis for empires like that of the Incas. However, these huacas were also the focus of local kinship relations and agrarian fertility rituals. The political structure that they articulated therefore had a built-in concern for the metaphysical reproduction of human, animal, and plant life. Political power in the pre-Columbian Andes was particularly bound up with attempts to control the flow of water across the frontier of life and death, resulting in no clear distinction between ritual and administration.

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