A Delayed Induced-Motion Illusion

Perception ◽  
1978 ◽  
Vol 7 (1) ◽  
pp. 85-89 ◽  
Author(s):  
George M Robinson ◽  
Janice Moulton
Keyword(s):  
Eye Movements ◽  
Visual Illusion ◽  
Perceptual Processing ◽  
Moving Target ◽  
Fixed Target ◽  
Aircraft Accidents ◽  
Motion Cues ◽  
Wide Range ◽  
Induced Motion ◽  
Series Of Experiments

We report a striking visual illusion which involves an induced motion that is delayed in time. An observer visually tracks a moving target in the neighborhood of a fixed target. The fixed target appears to be entrained by the moving target and appears to follow its movements after a lag of 0.33 second. A series of experiments showed that while the illusion depends on low background salience it obtains with both smooth and oscillatory motion in all directions including depth, under monocular and binocular viewing, in the absence of vestibular and kinesthetic motion cues or eye movements, and under a wide range of relative and absolute target luminance and position. The strength of the illusion and the magnitude of the induced movement's delay seem not to depend on any of the above factors. The illusion, by resisting a peripheral explanation, may provide some clues to central perceptual processing. In addition, we suggest the possibility that errors of judgment based on the nonveridical perception of motion displaced in time may play a role in nighttime automobile and aircraft accidents.

Pulfrich Effect and the Filling in of Apparent Motion

Perception ◽  
1976 ◽  
Vol 5 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Michael J Morgan
Keyword(s):  
Eye Movements ◽  
Apparent Motion ◽  
Visual Direction ◽  
Moving Target ◽  
Alignment Technique ◽  
Pulfrich Effect ◽  
Series Of Experiments ◽  
Tracking Eye Movements ◽  
As If

In the stroboscopic version of the Pulfrich effect a filter is able to induce depth shifts in a target as if the latter were moving continuously, rather than merely occupying a series of discrete positions. This was examined in a further series of experiments, in which a visual alignment technique was used to measure the perceived visual direction of an apparently moving target in intervals between its presentations. Results showed that the target has approximately the visual direction that it would have if it were moving continuously. This ‘filling in’ of apparent motion was shown to occur before the level of stereopsis. The possible influence of tracking eye movements is discussed.

scholarly journals Transient spatiotopic integration across saccadic eye movements mediates visual stability

2013 ◽  
Vol 109 (4) ◽  
pp. 1117-1125 ◽  
Author(s):  
Guido M. Cicchini ◽  
Paola Binda ◽  
David C. Burr ◽  
M. Concetta Morrone
Keyword(s):  
Eye Movements ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Spatial Integration ◽  
Interaction Field ◽  
Wide Range ◽  
External Objects ◽  
Induced Motion ◽  
Integration Mechanisms ◽  
The Relationship

Eye movements pose major problems to the visual system, because each new saccade changes the mapping of external objects on the retina. It is known that stimuli briefly presented around the time of saccades are systematically mislocalized, whereas continuously visible objects are perceived as spatially stable even when they undergo large transsaccadic displacements. In this study we investigated the relationship between these two phenomena and measured how human subjects perceive the position of pairs of bars briefly displayed around the time of large horizontal saccades. We show that they interact strongly, with the perisaccadic bar being drawn toward the other, dramatically altering the pattern of perisaccadic mislocalization. The interaction field extends over a wide range (200 ms and 20°) and is oriented along the retinotopic trajectory of the saccade-induced motion, suggesting a mechanism that integrates pre- and postsaccadic stimuli at different retinal locations but similar external positions. We show how transient changes in spatial integration mechanisms, which are consistent with the present psychophysical results and with the properties of “remapping cells” reported in the literature, can create transient craniotopy by merging the distinct retinal images of the pre- and postsaccadic fixations to signal a single stable object.

scholarly journals Voluntary modification of rapid tactile-motor responses during reaching differs from its visuo-motor counterpart

2020 ◽  
Author(s):  
Sasha Reschechtko ◽  
J. Andrew Pruszynski
Keyword(s):  
Motor Response ◽  
Tactile Feedback ◽  
Moving Target ◽  
Visually Guided ◽  
Motor Responses ◽  
Tactile Stimuli ◽  
Rapid Responses ◽  
Wide Range ◽  
Series Of Experiments ◽  
Visual Motor

AbstractPeople commonly hold and manipulate a variety of objects in everyday life, and these objects have different physical properties. In order to successfully control this wide range of objects, people must associate new patterns of tactile stimuli with appropriate motor outputs. We performed a series of experiments investigating the extent to which people can voluntarily modify tactile-motor associations in the context of a rapid tactile-motor response guiding the hand to a moving target (previously described in Pruszynski et al. 2016) by using an anti-reach paradigm in which participants were instructed to move their hands in the opposite direction of a target jump. We compared performance to that observed when people make visually guided reaches to a moving target (cf. Day & Lyon 2000, Pisella et al. 2000). When participants had visual feedback, motor responses during the anti-reach task showed early automatic responses toward the moving target before voluntary modification to move in the instructed direction. When the same participants had only tactile feedback, however, they were able to suppress this early phase of the motor response, which occurs less than 100 ms after the target jump. Our results indicate that, while the tactile motor and visual motor systems both support rapid responses that appear similar under some conditions, these responses show sharp distinctions in terms of their malleability.

Research of the activity and viability of spermatozoa at different concentrations and proportions of diluents after incubation

2020 ◽  
pp. 88-95
Author(s):  
Svitlana Lobchenko ◽  
Tetiana Husar ◽  
Viktor Lobchenko
Keyword(s):  
Plasma Concentration ◽  
Incubation Time ◽  
Coefficient Of Variation ◽  
Incubation Medium ◽  
Wide Range ◽  
Series Of Experiments ◽  
The Subject ◽  
Boar Spermatozoa ◽  
Native Plasma ◽  
Better Than

The results of studies of the viability of spermatozoa with different incubation time at different concentrations and using different diluents are highlighted in the article. (Un) concentrated spermatozoa were diluented: 1) with their native plasma; 2) medium 199; 3) a mixture of equal volumes of plasma and medium 199. The experiment was designed to generate experimental samples with spermatozoa concentrations prepared according to the method, namely: 0.2; 0.1; 0.05; 0.025 billion / ml. The sperm was evaluated after 2, 4, 6 and 8 hours. The perspective of such a study is significant and makes it possible to research various aspects of the subject in a wide range. In this regard, a series of experiments were conducted in this area. The data obtained are statistically processed and allow us to highlight the results that relate to each stage of the study. In particular, in this article it was found out some regularities between the viability of sperm, the type of diluent and the rate of rarefaction, as evidenced by the data presented in the tables. As a result of sperm incubation, the viability of spermatozoa remains at least the highest trend when sperm are diluted to a concentration of 0.1 billion / ml, regardless of the type of diluent used. To maintain the viability of sperm using this concentration of medium 199 is not better than its native plasma, and its mixture with an equal volume of plasma through any length of time incubation of such sperm. Most often it is at this concentration of sperm that their viability is characterized by the lowest coefficient of variation, regardless of the type of diluent used, which may indicate the greatest stability of the result under these conditions. The viability of spermatozoa with a concentration of 0.1 billion / ml is statistically significantly reduced only after 6 or even 8 hours of incubation. If the sperm are incubated for only 2 hours, regardless of the type of diluent used, the sperm concentrations tested do not affect the viability of the sperm. Key words: boar, spermatozoa, sperm plasma, concentration, incubation, medium 199, activity, viability, rarefaction.

scholarly journals The effect of water immersion on vection in virtual reality

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Géraldine Fauville ◽  
Anna C. M. Queiroz ◽  
Erika S. Woolsey ◽  
Jonathan W. Kelly ◽  
Jeremy N. Bailenson
Keyword(s):  
Virtual Reality ◽  
Motion Sickness ◽  
Water Immersion ◽  
Sensory Information ◽  
Future Research ◽  
Visually Induced Motion Sickness ◽  
Wide Range ◽  
Induced Motion ◽  
Ground Condition ◽  
The Impact

AbstractResearch about vection (illusory self-motion) has investigated a wide range of sensory cues and employed various methods and equipment, including use of virtual reality (VR). However, there is currently no research in the field of vection on the impact of floating in water while experiencing VR. Aquatic immersion presents a new and interesting method to potentially enhance vection by reducing conflicting sensory information that is usually experienced when standing or sitting on a stable surface. This study compares vection, visually induced motion sickness, and presence among participants experiencing VR while standing on the ground or floating in water. Results show that vection was significantly enhanced for the participants in the Water condition, whose judgments of self-displacement were larger than those of participants in the Ground condition. No differences in visually induced motion sickness or presence were found between conditions. We discuss the implication of this new type of VR experience for the fields of VR and vection while also discussing future research questions that emerge from our findings.

The State of the Art of Rubber-Seal Technology

1987 ◽  
Vol 60 (3) ◽  
pp. 381-416 ◽  
Author(s):  
B. S. Nau
Keyword(s):  
State Of The Art ◽  
Test Procedure ◽  
Working Party ◽  
The State ◽  
Supporting Evidence ◽  
Wide Range ◽  
Lip Seals ◽  
Alternative Hypotheses ◽  
Series Of Experiments ◽  
Range Of Values

Abstract The understanding of the engineering fundamentals of rubber seals of all the various types has been developing gradually over the past two or three decades, but there is still much to understand, Tables V–VII summarize the state of the art. In the case of rubber-based gaskets, the field of high-temperature applications has scarcely been touched, although there are plans to initiate work in this area both in the U.S.A. at PVRC, and in the U.K., at BHRA. In the case of reciprocating rubber seals, a broad basis of theory and experiment has been developed, yet it still is not possible to design such a seal from first principles. Indeed, in a comparative series of experiments run recently on seals from a single batch, tested in different laboratories round the world to the same test procedure, under the aegis of an ISO working party, a very wide range of values was reported for leakage and friction. The explanation for this has still to be ascertained. In the case of rotary lip seals, theories and supporting evidence have been brought forward to support alternative hypotheses for lubrication and sealing mechanisms. None can be said to have become generally accepted, and it remains to crystallize a unified theory.

scholarly journals Crashworthiness of Safe Fuels

1972 ◽  
Author(s):  
R. A. Rockow ◽  
L. M. Shaw
Keyword(s):  
Performance Evaluation ◽  
Fire Hazard ◽  
Full Scale ◽  
Safety Performance ◽  
Screening Tests ◽  
Aircraft Accidents ◽  
The Past ◽  
Relative Safety ◽  
Series Of Experiments ◽  
Aircraft Crash

Safety fuels such as emulsified and gelled fuels have been studied over the past several years as one means for reducing the post-crash fire hazard associated with aircraft accidents. However, through the work described herein, only recently has a quantitative evaluation been made to characterize the safety performance of these fuels. The safety performance evaluation program described in this paper includes an initial series of screening tests designed to obtain the characteristics of safe fuels in the aircraft crash environment. The authenticity of the screening tests relative to the full-scale crash environment was evaluated through a second series of experiments designed to simulate a full-scale aircraft crash environment. A crashworthiness evaluation criterion was established in terms of an “ignition susceptibility parameter” to quantitize the relative safety performance of different fuels. The conclusions of this research clearly show that significant savings in lives and equipment can be realized if safe fuels which perform within the non-hazardous envelope of the ignition susceptibility parameter are operationally incorporated in present-day aircraft.

scholarly journals MEASURING DISPLACEMENT AND VELOCITY OF A STRIKER USING A RADIO-INTERFEROMETER

2019 ◽  
Vol 81 (1) ◽  
pp. 118-128
Author(s):  
V. V. Balandin ◽  
V. V. Balandin ◽  
V. V. Parkhachev
Keyword(s):  
High Speed ◽  
Radio Interferometer ◽  
Experimental Investigations ◽  
X Ray ◽  
Gas Gun ◽  
Impact Interaction ◽  
Ballistic Experiment ◽  
Wide Range ◽  
Series Of Experiments ◽  
Error Of Measurement

Investigating impact interaction of solid and deformed bodies with obstacles of various physical natures requires developing experimental methodologies of registering the parameters of the interaction process. In experimental investigations of impact interaction of solids, it is common practice to measure displacement of strikers as a function of time, as well as their velocity and deceleration. To determine the displacement and velocity of a striker, a radio-interferometric methodology of registering the displacement of its rear end is proposed. In contrast with the registration methods based on high-speed filming and pulsed X-ray photography, the method using a millimeter-range radio-interferometer provides continuous high-accuracy registering of the displacement of the rear end of a striker in a wide range of displacement values. To test the effectiveness of the methodology, a series of experiments have been conducted on registering the motion of a cylindrical striker of an aluminum alloy, fired from a 20mm-dia gas gun. The displacement of the striker was also monitored using high-speed filming. The results of measuring using the two methodologies differ within the limits of the error of measurement. Based on the results of the above experiments, it has been concluded that the methodology of determining the displacement and velocity of strikers in a ballistic experiment using a mm-range radio-interferometer makes it possible to measure practically continuously large displacements (100 mm and larger) to a safe accuracy. The present methodology can be used for measuring the displacement and velocity of the rear end of a striker interacting with obstacles of various physical natures (metals, ceramics, soils, concretes, etc.).

scholarly journals Silica-encapsulated DNA tracers for measuring aerosol distribution dynamics in real-world settings

2021 ◽  
Author(s):  
Anne M Luescher ◽  
Julian Koch ◽  
Wendelin J Stark ◽  
Robert N Grass
Keyword(s):  
Real World ◽  
Complex Dynamics ◽  
Quantitative Polymerase Chain Reaction ◽  
Cost Effective ◽  
Confined Space ◽  
Aerosol Dynamics ◽  
Novel Approach ◽  
Aerosol Distribution ◽  
Wide Range ◽  
Series Of Experiments

Aerosolized particles play a significant role in human health and environmental risk management. The global importance of aerosol-related hazards, such as the circulation of pathogens and high levels of air pollutants, have led to a surging demand for suitable surrogate tracers to investigate the complex dynamics of airborne particles in real-world scenarios. In this study, we propose a novel approach using silica particles with encapsulated DNA (SPED) as a tracing agent for measuring aerosol distribution indoors. In a series of experiments with a portable setup, SPED were successfully aerosolized, re-captured and quantified using quantitative polymerase chain reaction (qPCR). Position-dependency and ventilation effects within a confined space could be shown in a quantitative fashion achieving detection limits below 0.1 ng particles per m3 of sampled air. In conclusion, SPED show promise for a flexible, cost-effective and low-impact characterization of aerosol dynamics in a wide range of settings.

scholarly journals Experimental investigation of the parameters of water solution purposes by ceramic, coal filters and reverse-osmotic module

2019 ◽  
pp. 30-33
Author(s):  
S.V. Gulienko
Keyword(s):  
Reverse Osmosis ◽  
Water Solution ◽  
Ceramic Filter ◽  
Main Process ◽  
Working Pressure ◽  
Ceramic Filters ◽  
Quality Of Water ◽  
Urgent Task ◽  
Wide Range ◽  
Series Of Experiments

The urgent task is to research in detail the possibilities of operation of the reverse osmosis membrane in the conditions of changing various parameters, which include, first of all, the working pressure, the initial concentration of the cleaning solutions, as well as the working conditions and the complete set of cleaning stands with auxiliary filters: mechanical, ceramic and carbon, which improves the quality of water and increases the life of high-value reverse osmosis modules. Particular attention was paid in this series of experiments to the role of ceramic filters, since in the previous series of experiments the concentration of the solution did not change both after mechanical and after carbon filters. Therefore, it was decided to modernize the stand and use a ceramic filter in the flow chart. In this work the detailed scheme of bench-scale setup with using of ceramic and carbon filters and also reverse-osmosis module is represented. The experimental reseaches of purification of NaCl water solutions were carried out in wide range of concentrations (0,2∙10-3…6,5 g/l) and working pressures (0,2…0,65 MPa). The comparative characteristics of main process parameters with and without ceramic filter are represented. The experiments were carried out on a laboratory stand for complex purification of aqueous solutions by microfiltration, adsorption and reverse osmosis using the following process steps carried out in the respective apparatus.

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