Direction of a Figural Retroactive-Effect as a Function of Apparent Temporal Overlap of Test and Inducing Figures

1974 ◽  
Vol 38 (1) ◽  
pp. 91-101
Author(s):  
June Adam ◽  
Ruth Heron ◽  
Donna Cooper ◽  
Alain Hepner
Keyword(s):  
Visual Illusion ◽  
Stimulus Sequence ◽  
Test Figure ◽  
Retroactive Effect ◽  
Series Of Experiments ◽  
Concentric Circles ◽  
Attraction Effects ◽  
Temporal Overlap

In a series of experiments using a concentric circles figure the direction of the figural retroactive-effect is related to the frequency with which Ss report apparent temporal overlap of inducing and test figures under different conditions of testing. The results suggest that figural retroactive-effects showing attraction of the test figure toward the inducing figure result from S's perception of a visual illusion during the stimulus sequence. Factors determining the occurrence of both apparent temporal overlap and attraction effects are investigated.

Investigation of Interactions of Luminance Contrast and Temporal Factors in Figural Aftereffects

1968 ◽  
Vol 27 (1) ◽  
pp. 287-291 ◽  
Author(s):  
June Adam ◽  
Marion Ring
Keyword(s):  
Exposure Time ◽  
Interstimulus Interval ◽  
Luminance Contrast ◽  
Test Figure ◽  
Time Condition ◽  
Temporal Factors ◽  
Concentric Circles

An experiment was designed to investigate the possibility of interactions between luminance contrast factors and temporal factors in determining the magnitude of the concentric-circles aftereffect. 24 combinations of inducing figure exposure time, condition of test figure presentation (determined by test figure exposure time and interstimulus interval), inducing figure luminance contrast and test-figure luminance contrast, were used. No interactions were found.

Effects of Luminance Contrast Factors upon Figural Aftereffects Induced by Short Fixation Periods

1966 ◽  
Vol 22 (2) ◽  
pp. 535-541 ◽  
Author(s):  
Margaret Gibb ◽  
Ivan Freeman ◽  
June Adam
Keyword(s):  
Luminance Contrast ◽  
Test Figure ◽  
General Finding ◽  
Concentric Circles

An experiment was designed to investigate the effects of luminance contrast factors upon the concentric circles aftereffect for very short periods of fixation. The general finding was that the immediate aftereffect increased as the luminance contrast of the inducing figure increased and decreased as the luminance contrast of the test figure increased.

The Orbison Visual Illusion and Radar Scopes

1986 ◽  
Vol 30 (2) ◽  
pp. 168-169
Author(s):  
Paul N. Rose
Keyword(s):  
College Students ◽  
Moving Objects ◽  
Visual Illusion ◽  
Female College Students ◽  
Male And Female ◽  
Female College ◽  
Concentric Circles

In the Orbison visual illusion, the sides of a square, although straight, appear to be bowed when the square is superimposed over a set of concentric circles. In the present study, the illusion is demonstrated for moving objects. Male and female college students watched carets move either across a background of four concentric circles or across a plain background. The carets moved across the top or along the left side of the scene. A number of situations were assessed. It was found that subjects do make errors that can be attributed to the Orbison illusion.

scholarly journals A Force-Directed Algorithm for Drawing Directed Graphs Symmetrically

2018 ◽  
Vol 2018 ◽  
pp. 1-24
Author(s):  
Taihua Xu ◽  
Jie Yang ◽  
Guanglei Gou
Keyword(s):  
Graph Drawing ◽  
State Of The Art ◽  
Directed Graphs ◽  
Human Perception ◽  
Series Of Experiments ◽  
Concentric Circles ◽  
Deterministic Strategy

Symmetry is one of the most important aesthetic criteria on graph drawing. It is quite necessary to measure the extent to which the drawings can be considered symmetric. For this purpose, a symmetric metric based on vertex coordinate calculation is proposed in this paper. It is proven theoretically and experimentally that the proposed metric is robust to contraction, expansion, and rotation of drawings. This robustness conforms to human perception of symmetry. Star-subgraphs and cycles are two common structures in digraphs. Both of them have inherent symmetry which should be displayed in drawings. For this purpose, a force-directed algorithm named FDS is proposed which can draw star-subgraphs and cycles as symmetrically as possible. FDS algorithm draws cycles as circles whose positions are fixed to provide a scaffolding for overall layout, renders non-leaf vertices by a standard force-directed layout, and places leaf vertices on concentric circles via a deterministic strategy. A series of experiments are carried out to test FDS algorithm. The results show that FDS algorithm draws digraphs more symmetrically than the existing state-of-the-art algorithms and performs efficiency comparable to O(nlog⁡n) YFHu algorithm.

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.

What Iconic Gesture Fragments Reveal about Gesture–Speech Integration: When Synchrony Is Lost, Memory Can Help

2011 ◽  
Vol 23 (7) ◽  
pp. 1648-1663 ◽  
Author(s):  
Christian Obermeier ◽  
Henning Holle ◽  
Thomas C. Gunter
Keyword(s):  
Target Word ◽  
Sentence Processing ◽  
Present Series ◽  
Iconic Gesture ◽  
Temporal Synchrony ◽  
Active Memory ◽  
Series Of Experiments ◽  
Task Conditions ◽  
Delayed Consequences ◽  
Temporal Overlap

The present series of experiments explores several issues related to gesture–speech integration and synchrony during sentence processing. To be able to more precisely manipulate gesture–speech synchrony, we used gesture fragments instead of complete gestures, thereby avoiding the usual long temporal overlap of gestures with their coexpressive speech. In a pretest, the minimal duration of an iconic gesture fragment needed to disambiguate a homonym (i.e., disambiguation point) was therefore identified. In three subsequent ERP experiments, we then investigated whether the gesture information available at the disambiguation point has immediate as well as delayed consequences on the processing of a temporarily ambiguous spoken sentence, and whether these gesture–speech integration processes are susceptible to temporal synchrony. Experiment 1, which used asynchronous stimuli as well as an explicit task, showed clear N400 effects at the homonym as well as at the target word presented further downstream, suggesting that asynchrony does not prevent integration under explicit task conditions. No such effects were found when asynchronous stimuli were presented using a more shallow task (Experiment 2). Finally, when gesture fragment and homonym were synchronous, similar results as in Experiment 1 were found, even under shallow task conditions (Experiment 3). We conclude that when iconic gesture fragments and speech are in synchrony, their interaction is more or less automatic. When they are not, more controlled, active memory processes are necessary to be able to combine the gesture fragment and speech context in such a way that the homonym is disambiguated correctly.

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

Slip traces caused by plastic deformation during recrystallization of thin metal sheets

1994 ◽  
Vol 52 ◽  
pp. 620-621
Author(s):  
H. Lin ◽  
D. P. Pope
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Sample Thickness ◽  
List Type ◽  
Metal Sheets ◽  
Second Phases ◽  
Slip Traces ◽  
Series Of Experiments ◽  
Cold Rolled ◽  
Individual Grains

During a study of mechanical properties of recrystallized B-free Ni3Al single crystals, regularly spaced parallel traces within individual grains were discovered on the surfaces of thin recrystallized sheets, see Fig. 1. They appeared to be slip traces, but since we could not find similar observations in the literature, a series of experiments was performed to identify them. We will refer to them “traces”, because they contain some, if not all, of the properties of slip traces. A variety of techniques, including the Electron Backscattering Pattern (EBSP) method, was used to ascertain the composition, geometry, and crystallography of these traces. The effect of sample thickness on their formation was also investigated.In summary, these traces on the surface of recrystallized Ni3Al have the following properties:1.The chemistry and crystallographic orientation of the traces are the same as the bulk. No oxides or other second phases were observed.2.The traces are not grooves caused by thermal etching at previous locations of grain boundaries.3.The traces form after recrystallization (because the starting Ni3Al is a single crystal).4.For thicknesses between 50 μm and 720 μm, the density of the traces increases as the sample thickness decreases. Only one set of “protrusion-like” traces is visible in a given grain on the thicker samples, but multiple sets of “cliff-like” traces are visible on the thinner ones (See Fig. 1 and Fig. 2).5.They are linear and parallel to the traces of {111} planes on the surface, see Fig. 3.6.Some of the traces terminate within the interior of the grains, and the rest of them either terminate at or are continuous across grain boundaries. The portion of latter increases with decreasing thickness.7.The grain size decreases with decreasing thickness, the decrease is more pronounced when the grain size is comparable with the thickness, Fig. 4.8.Traces also formed during the recrystallization of cold-rolled polycrystalline Cu thin sheets, Fig. 5.

Dissection of the molecular mechanisms of protein targeting to the peroxisome using immunofluorescence and immunocryoelectron microscopies

1990 ◽  
Vol 48 (3) ◽  
pp. 44-45
Author(s):  
G-A. Keller ◽  
S. J. Gould ◽  
S. Subramani ◽  
S. Krisans
Keyword(s):  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Protein Targeting ◽  
Firefly Luciferase ◽  
Peroxisomal Enzyme ◽  
Transfected Cells ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Series Of Experiments ◽  
Peroxisomal Targeting Signal

Subcellular compartments within eukaryotic cells must each be supplied with unique sets of proteins that must be directed to, and translocated across one or more membranes of the target organelles. This transport is mediated by cis- acting targeting signals present within the imported proteins. The following is a chronological account of a series of experiments designed and carried out in an effort to understand how proteins are targeted to the peroxisomal compartment.-We demonstrated by immunocryoelectron microscopy that the enzyme luciferase is a peroxisomal enzyme in the firefly lantern. -We expressed the cDNA encoding firefly luciferase in mammalian cells and demonstrated by immunofluorescence that the enzyme was transported into the peroxisomes of the transfected cells. -Using deletions, linker insertions, and gene fusion to identify regions of luciferase involved in its transport to the peroxisomes, we demonstrated that luciferase contains a peroxisomal targeting signal (PTS) within its COOH-terminal twelve amino acid.

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