Illusory Figures from Stereoscopically Three-Dimensional Inducers Depicting No Occlusion Event

Perception ◽  
1995 ◽  
Vol 24 (8) ◽  
pp. 905-918 ◽  
Author(s):  
Franco Purghé
Keyword(s):  
Three Dimensional ◽  
Illusory Figure ◽  
Pictorial Representations ◽  
Contrary Evidence

It has been claimed that an illusory figure is prevented from occurring when there is contrary evidence to occlusion, eg when the inducers are pictorial representations of ‘complete’ three-dimensional (3-D) objects. However, it was recently shown that illusory figures may also be induced by such pictorially 3-D inducers. Here, further evidence on this point is presented. Two experiments were carried out. The first was aimed at showing that an illusory figure can be induced even by stereoscopically 3-D ‘complete’ inducers; the second was aimed at checking whether inducers that are stereoscopically seen as closer than the induced figure can contribute to strengthen the illusion. The results show that stereoscopically 3-D inducing patterns can affect the illusion both in the absence of any occlusion cue and when there is contrary evidence to occlusion. These conclusions seriously challenge all the interpretations that regard occlusion, or interposition, cues as necessary for the formation of illusory figures.

Illusory Contours from Pictorially Three-Dimensional Inducing Elements: Counterevidence for Parks and Rock's Example

Perception ◽  
1993 ◽  
Vol 22 (7) ◽  
pp. 809-818 ◽  
Author(s):  
Franco Purghé
Keyword(s):  
Three Dimensional ◽  
Illusory Figure ◽  
Illusory Contours ◽  
Line Elements

In 1990 Parks and Rock claimed that, in pictorially three-dimensional (3-D) inducing patterns, an illusory figure does not emerge if a clear occlusion event is not present. A new pictorially 3-D pattern is presented which contradicts this claim. Two experiments were carried out. The first was aimed at ascertaining the presence of an illusory figure in the new 3-D pattern; the second was aimed at offering evidence that in Parks and Rock's pattern the disappearance of the illusory figure could be due to local interferences caused by the line elements in contact with the inducing borders. The results tend to contradict Parks and Rock's conclusions.

Can Illusory Figures Be Transparent and Opaque at the Same Time?

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 321-321
Author(s):  
F Purghé
Keyword(s):  
Visual System ◽  
Necker Cube ◽  
Special Kind ◽  
Illusory Figure ◽  
Cognitive Problem ◽  
Paradoxical Result ◽  
Contrary Evidence

A simple and convincing way of explaining illusory figures is based upon the idea that the visual system would infer the presence of an occluding object when the inducing pattern shows features, such as indentations or interruptions, that can be logically explained as due to an occlusion. This kind of explanation implies (a) that an illusory figure should be prevented from occurring if there is no logical need for it, and (b) that the illusory figure must be opaque to be effective as an occluding object. It can be shown, however, that illusory figures can emerge even when there is contrary evidence to occlusion. A special kind of stereoscopic Kanizsa-like pattern superimposed onto a picture (an Escher engraving) is capable of inducing clear illusory figures (two rectangles). In this pattern, the illusory figures seem to be transparent with respect to the picture on the background, which remains fully visible through them, but act as opaque surfaces with respect to the inducers. The inducers are parts of a Necker cube which can be clearly seen only when its fragments induce the illusory rectangles, but disappears if the same fragments, being only outlined, are not able to induce them. If this outcome can be regarded as a demonstration that the Necker cube can be seen as an amodally completed object only when it virtually completes itself ‘behind’ the illusory rectangles, one would have to conclude that the same illusory surfaces can be transparent and opaque at the same time. This paradoxical result seems to challenge any interpretation of illusory figures as being due to an intelligent solution to a cognitive problem.

Three-Dimensional Illusory Objects Produced by Rotation in Depth

Perception ◽  
1994 ◽  
Vol 23 (8) ◽  
pp. 905-912 ◽  
Author(s):  
Ilpo Kojo ◽  
Marja Liinasuo ◽  
Jyrki Rovamo
Keyword(s):  
Computer Animation ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Illusory Figure ◽  
Three Dimensional Objects ◽  
Dimensional Object

Rotation of a Kanizsa triangle in depth around its vertical axis causes a perception of a three-dimensional object with a flat, rigid illusory triangle between the inducing discs. When the inducing discs of a Kanizsa triangle were made thicker, the illusory triangle between the discs also became thicker. In the experiments both computer animation and real inducers made of plastic were used. The method promoted border perception in a three-dimensional illusory figure. We suggest that the perception of three-dimensional illusory objects is due to a process which is also used in the perception of real three-dimensional objects.

scholarly journals Gender Representation in EFL Textbooks in Saudi Arabia: A Critical Discourse Analysis Approach

2018 ◽  
Vol 7 (5) ◽  
pp. 151
Author(s):  
Wafa Aljuaythin
Keyword(s):  
Critical Discourse Analysis ◽  
Three Dimensional ◽  
Model Description ◽  
Three Dimensional Model ◽  
Representation Of Women ◽  
The Social ◽  
Three Stages ◽  
Underrepresentation Of Women ◽  
Pictorial Representations ◽  
Domestic Roles

This study investigates the representation of gender in two English as a Foreign Language textbooks for elementary students in Saudi schools. It employs the three stages of Fairclough’s (2015) three-dimensional model: description, interpretation, and explanation. The analysis phase of the description stage is concerned with analyzing four aspects: the frequency of male and female occurrences, the kinds of activity that the two genders engage in, the pictorial representations of the two genders, and the social and domestic roles associated with males and females. Subsequently, after compiling quantitative data on these aspects, the analysis moves to a qualitative interpretation of these aspects in relation to the social context. In the final stage of the analysis, when the discussion aims to reach a final critical explanation on the macro level, the underlying ideological functions of power relations and social struggles are explained in terms of the dominance approach to language (Spender, 1980). The analysis of the two textbooks reveals a gender imbalance in favor of males. This imbalance has led to the representation of women as marginalized and stereotypical figures. This study suggests that such an underrepresentation of women could create a false reality surrounding perceptions of women and hinder the process of ensuring equality to all humans.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

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