Preattentive processing of object size: implications for theories of size perception

Information about the visual angle size of objects is important for maintaining object constancy with variations in viewing distance. Although human observers are quite accurate at judging spatial separations (or cross-sectional size), they are prone to error when there are other spans nearby, as in classical illusions such as the Müller-Lyer illusion. It is possible to reconcile these aspects of size perception by assuming that the size domain is sampled sparsely. It was shown by means of a visual search procedure that the size of objects is processed preattentively and in parallel across the visual field. It was demonstrated that an object's size, rather than its boundary curvature or spatial-frequency content, provides the basis for parallel visual search. It was also shown that texture borders could be substituted for luminance borders, indicating that object boundaries at the relevant spatial scale provide the input to size perception. Parallel processing imposes a severe computational constraint which provides support for the assumption of sparse sampling. An economical model based on several broadly tuned layers of size detectors is proposed to account for the parallel extraction of size, the Weberian behaviour of size discrimination, and the occurrence of strong interference effects in the size domain.     

The role of grain size and strain in work hardening and texture development

Polycrystalline copper (99.999 pct) having four different grain sizes (from 4 to 220 μm) was strained in tension at room temperature to true plastic strains of 0.05, 0.10, 0.20, and 0.30. The initial texture of the materials was determined by neutron diffraction, as were the deformation textures. Both inverse pole figures and calculated TaylorM factors were then derived from the data. In general, it was observed that the texture strengthens at increasing strain and that the effect of grain size on this development is not very pronounced. The measured change in the volume concentration of the (111) texture component was compared to that obtained from a model simulation, and in general, the experiments and the simulations agreed well. The effect on the flow stress of the initial texture, and on the texture which develops during straining, could be accounted for on the basis of TaylorM factors calculated from the experimental results, and it was found that there is an effect of texture on the flow stress. The flow stress at strains above yield, expressed as a modified Hall-Petch relationship, was not greatly affected by corrections toM induced by strain and grain size.     

Haptic integration of planar size with hardness, texture, and planar contour.

Three experiments involving a total of 75 college students investigated the role of size information in haptic classification of custom-made planar objects when size covaries with hardness, texture, or planar contour. Exp 1 showed facilitation of classification by redundant (RD) size and shape cues, indicating the coprocessing of size and shape. Exps 2 and 3 used a withdrawal paradigm: Classification trials began with 2 RD properties, and 1 was then held constant (withdrawn). Exp 2 showed that when size and shape were RD, withdrawal of either impaired responses, whereas when size was RD with texture or hardness, only size withdrawal had an effect. Exp 3 demonstrated that this size weighting was not restricted to a single procedure for exploration. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of size, shape and hardness of particles in suspension on oral texture and palatability

Trans-species, multiple site (particularly common site between species), mutagenic rodent carcinogens are less affected by the influences of polymorphic genes than are chemicals inducing more limited carcinogenic effects. Trans-species carcinogens, therefore, should represent a first priority for attention for human health risk.     

Surface orientation from texture: ideal observers, generic observers and the information content of texture cues

Perspective views of textured, planar surfaces provide a number of cues about the orientations of the surfaces. These include the information created by perspective scaling of texture elements (scaling), the information created by perspective foreshortening of texels (foreshortening) and, for textures composed of discrete elements, the information created by the effects of both scaling and foreshortening on the relative positions of texels (position). We drive a general form for ideal observers for each of these cues as they appear in images of spatially extended textures, (e.g. those composed of solid 2-D figures). As an application of the formulation, we derive a set of 'generic' observers which we show perform near optimally for images of a broad range of surface textures, without special prior knowledge about the statistics of the textures. Using simulations of ideal observers, we analyze the informational structure of texture cues, including a quantification of lower bounds on reliability for the three different cues, how cue reliability varies with slant angle and how it varies with field of view. We also quantify how strongly the reliability of the foreshortening cue depends on a prior assumption of isotropy. Finally, we extend the analysis to a naturalistic class of textures, showing that the information content of textures particularly suited to psychophysical investigation can be quantified, at least to a first-order approximation. The results provide an important computational foundation for psychophysical work on perceiving surface orientation from texture.     

Effect of melt spinning on grain size and texture in Ni-Mo alloys

Chill block melt spun ribbons of nickel molybdenum alloys with molybdenum contents of 8 to 41.8 wt pct Mo have been examined for their microstructure and texture dependence on processing conditions. Linear features observed in grains solidified with a planar liquid-solid interface at the quench side of the ribbons have been identified to be due to the twins on (111),, plane formed during solidification. Grain size variation with the wheel surface speed and the alloy composition has been studied. Crystallographic texture on quench side and free surface side of the ribbons has been investigated.     

Minimum size of mammalian homeotherms: role of the thermal environment

The minimum size of a mammalian homeotherm appears to be related to the animal's maximum rate of endogenous heat production, the ambient thermal environment, and the animal's ability to be a facultative homeotherm.     

Eyewitness recall: Regulation of grain size and the role of confidence.

Eyewitness testimony plays a critical role in Western legal systems. Three experiments extended M. Goldsmith, A. Koriat, and A. Weinberg-Eliezer's (2002) framework of the regulation of grain size (precision vs. coarseness) of memory reports to eyewitness memory. In 2 experiments, the grain size of responses had a large impact on memory accuracy. Further, participants achieved a compromise between the accuracy and informativeness of their testimony by volunteering precise answers only when likely to be correct. The level of detail reported was strongly, positively related to confidence in the accuracy of the response. This highlights the importance of considering the level of detail, not just the accuracy, of eyewitness testimony. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of grain size and annealing texture on the cyclic response and the substructure evolution of polycrystalline copper

In attempting to interpret the mechanical response of polycrystalline copper, for which the results in the literature show marked scatter, the effects of microstructure on the cyclic behavior and the substructure evolution of copper polycrystals have been investigated. The microstructure is described by a complex factor—grain size and texture combined. It is found that there is a very significant effect of microstructure in the cyclic response of copper at low and intermediate strain amplitudes, where dislocation structures which localize deformation are expected to be present. In general, the cyclic response of coarse-grained copper shows a much more pronounced cyclic hardening and higher saturation stresses than those for fine-grained copper. This behavior is associated with a well defined hard 〈111〉−〈100〉 fiber texture, inherited in the coarse-grained material after annealing at relatively high temperatures. The multiple slip associated with the 〈111〉−〈001〉 oriented grains homogenizes the deformation very early, resulting in strong cyclic hardening, and a faster substructure evolution into cell structure.     

Effect of grain size and texture on the mechanical properties of warm worked cadmium-1.5 Pct zinc alloy

The structural changes occurring during warm working of Cd-1.5 pct Zn alloy and their effect on the subsequent mechanical properties are studied. It is observed that changes in grain size and preferred orientation are important to a large extent in controlling the mechanical strength. The Hall-Petch slope,R decreases in the warm worked material while the friction stress, σ_o increases. The lowerR values are attributed to the development of a {10-1t} texture and the higher σ_o values are interpreted on the basis of changes in the basal texture.     

Influence of simultaneous variation in size of type, width of line, and leading for newspaper type.

A speed of reading technique was employed with 820 readers to determine the effect on legibility of simultaneous variation of type size, line width, and leading for Excelsior newspaper type. 9 typographical variations were compared with text set in 8-point type in a 12-pica line width with 2-point leading. Results revealed that 7-, 8-, and 9-point type in a 12-pica line width with 2-point leading were read most rapidly and equally fast. But text in relatively long lines, very short lines, and small type size, or combinations of these with little or no leading were read significantly slower than the standard. Judgments for relative legibility and pleasingness revealed a reader preference for 8- or 9-point type with 2-point leading in a line width of 12 picas (12 or 18 picas for 9-point type). Text in relatively long or short lines, small type size, and no leading received low ratings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modification of the effects of prior residence in xiphophorus (Pisces, Poeciliidae): the role of isolation and differences in size

Laboratory experiments on pairs of male male of the genus Xiphophorus were carried out to test the hypothesis that the duration of a pre-experimental isolation period would modify the effects of prior residence on aggressive behaviour and dominance. Resident and intruder were isolated either both for 3 or both for 22 h (Exp. 1), or one for 3 and other other for 22 h (Exp. 2). Prior residence effects were only evident when the resident had been isolated for 3 h. Other connections between isolation conditions, reciprocal aggression and final dominance were also analysed, as was the influence of size differences between the opponents.     

Alterations in the charge and size selectivity barrier of the glomerular filter in aminonucleoside nephrosis in rats

The aminonucleoside of puromycin induces proteinuria and renal damage when given to rats. Aminonucleoside of puromycin was administered to male Wistar-Furth rats as a single intravenous injection in a dose of 15 mg. per 100 gm. of body weight. The animals were studied 9 days later when the mean urinary protein was 175 mg. per 24 hours. Evidence of glomerular epithelial cell injury included massive obliteration of foot processes, appearance of microvilli, protein reabsorption droplets, extreme attenuation of cytoplasm with formation of blebs, and focal detachment of epithelial cells from glomerular basement membrane. An increase in both the amount of mesangial matrix and the number of mesangial cells was also observed. The fractional clearance (C/GFR) of anionic horseradish peroxidase had increased 18.5 times as compared to control values and was nearly equal to the C/GFR of neutral horseradish peroxidase in the experimental rats. The C/GFR of cationic horseradish peroxidase was decreased by one-third so that it approximated the C/GFRs of both anionic and neutral horseradish peroxidase. These findings indicate a nearly complete loss of the charge-selective barrier to filtration. In addition, C/GFRs of tritiated uncharged dextrans with a range of molecular radii from 18 to 58 Angstrom (A) were determined. The C/GFRs of dextrans (alpha e less than 30 A) were decreased in the experimental rats as compared to C/GFRs of dextrans of corresponding molecular size in control rats. However, the C/GFRs of dextrans (alpha e greater than 38A) were increased in experimental as compared to control rats. Further, both anionic and cationic ferritin (alpha e = 61 A) were observed in the urinary space near denuded areas of glomerular basement membrane. These results indicate that the size-selective properties of the glomerular barrier to filtration have been modified with decreased C/GFR of small molecules and increased C/GFR of large molecules. Thus, the proteinuria of aminonucleoside nephrosis in rats occurs secondary to alterations in both the charge- and size-selective barriers to glomerular filtration.     

Tachycardia preconditions infarct size in dogs: role of adenosine and protein kinase C

BACKGROUND: Myocardial ischemic preconditioning is a well-known phenomenon, however there is scant information in regard to nonischemic preconditioning. METHODS AND RESULTS: We studied in anesthetized dogs the preconditioning effect of tachycardia and the mediation of adenosine and protein kinase C in this process. In a control group the anterior descending coronary artery was occluded for 60 minutes and reperfused for 270 minutes. Heart rate was kept constant at 120 +/- 5 cycles/min and aortic pressure changes were damped. The infarct size (necrotic volume/risk region volume x 100) was 15.8 +/- 1.5%. In another group of dogs a similar protocol was followed, but five periods of tachycardia (213 +/- 12 cycles/min), 5 minutes in duration each, with 5 minutes of intervening periods at control heart rate, were induced previous to the coronary occlusion. The infarct size was reduced by 46% (P<.001) with respect to the nonpreconditioned group. This effect was not due to changes in collateral flow nor risk region size. During tachycardia, myocardial interstitial adenosine increased about twofold (P<.05); no metabolic, hemodynamic, or ECG evidences of ischemia were observed and the transmural vasodilatory reserve was preserved. The blockade of adenosine receptors with 8 phenyltheophylline, before or after the preconditioning tachycardia, reverted its protecting effect but it did not modify infarct size in nonpreconditioned dogs. No changes in cytosolic or particulate protein kinase C activity or translocation of alpha-, beta-, epsilon-, and zeta- protein kinase C isozyme by effect of tachycardia or ischemia were observed between preconditioned and nonpreconditioned dogs. CONCLUSIONS: Tachycardia, in the absence of ischemia, mimics the preconditioning effect of ischemia in the dog. This effect is mediated by adenosine but not by changes in protein kinase C activity or its translocation.     

Variables related to premature terminations in a university counseling service: A comment on Rodolfa, Rapaport, and Lee.

Comments on the study of E. R. Rodolfa et al (see record 1983-11046-001) on the influence of the variables of sex and experience level of intaker and assigned counselor, sex of client, and administrative variables in premature termination in counseling. Their findings revealed that administrative variables were the major factors related to premature termination. The present author contends that despite the adherence to several well-accepted canons of scientific research reporting, the implementation of these principles was faulty because the authors were not familiar with relevant research. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)