Effect of Varying and Nonvarying Stimulus Consequences on Visual Persistence in Twenty-Month-Old Infants

1968 ◽  
Vol 26 (3) ◽  
pp. 883-887 ◽  
Author(s):  
Paul Weisberg ◽  
Edward Fink
Keyword(s):  
Visual Persistence ◽  
The Other ◽  
Constant Light ◽  
Light Group ◽  
Screen Constant

40 Ss, divided into 4 groups, peered into a chamber and by so doing, exposed a slide. For half the Ss, continued peering regularly presented a new slide which consisted either of colorful pictures (varied-picture group) or a lighted screen of various brightness levels (varied-light group) while for the other half, continued peering always re-presented the same slide which consisted either of a colorful picture (constant-picture group) or a lighted screen (constant-light group). The varied-picture group relative to the other groups exposed the most slides and tended to take a single long look when a slide was exposed. In terms of this visual persistence pattern, the constant-picture group outperformed the remaining two groups. No significant differences were found between the constant-light and varied-light groups on any measure of persistence.

scholarly journals INFLUENCE OF LIGHT ON THE GROWTH AND MALIGNANCY OF A TRANSPLANTABLE NEOPLASM OF THE RABBIT

1927 ◽  
Vol 45 (3) ◽  
pp. 483-496 ◽  
Author(s):  
Louise Pearce ◽  
C. M. Van Allen
Keyword(s):  
Experimental Evidence ◽  
Malignant Disease ◽  
External Factor ◽  
Continuous Light ◽  
Ultra Violet ◽  
The Other ◽  
Constant Light ◽  
Constant Darkness ◽  
Light Conditions ◽  
The One

An experiment is reported in which an environment of constant and continuous light excluding the shorter ultra-violet rays, and one of constant darkness, have influenced the course and character of a malignant disease of rabbits induced by a transplantable neoplasm. Under the influence of constant light the level of malignancy was observed to be low; under the influence of constant darkness the level of malignancy was somewhat lower than in the control animals living under ordinary indoor light conditions, but the level was not as low as among the animals constantly illuminated. These observations furnish experimental evidence in support of the idea that there is a correlation between the external factor of light on the one hand and the manifestations of an experimental malignant disease on the other.

scholarly journals The Role of Ethylene in the Development of Constant-light Injury of Potato and Tomato

1998 ◽  
Vol 123 (2) ◽  
pp. 239-245 ◽  
Author(s):  
Kent E. Chushman ◽  
Theodore W. Tibbitts
Keyword(s):  
Starch Content ◽  
Chlorophyll Concentration ◽  
Acc Oxidase ◽  
Dry Mass ◽  
The Other ◽  
Constant Light ◽  
Antisense Gene ◽  
Silver Thiosulfate ◽  
Necrotic Spotting

The role of tehylene in the development of constant-light injury of potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum Mill.) was investigated. In one study, silver thiosulfate (STS) was applied to the foliage of four potato cultivars growing under constant light. Leaf area and shoot dry mass of `Kennebec' and `Superior', cultivars normally injured by constant light, were greater (P<0.05) than those of control plantsgiven foliar applications of distilled water. Examination of STS-treated `Kennebec' leaflets revealed significantly less injury (necrotic spotting and reduced starch content) than the water-treated controls. `Norland' and `Denali', cultivars tolerant of constant light, exhibited no differences in growth between treatments. In a second study, injury (necrotic spotting and reduced starch content) was induced in leaflets of `Denali' when exposed to spray applications of 0.5 mmol·L-1 ethephon or air containing 0.5 to 0.8 μL·L-1 ethylene. In a third study, three genotypes of `Ailsa Craig' tomato were grown under constant light. Leaves of the normal `Ailsa Craig' exhibited epinasty, reduced chlorophyll concentration, and reduced starch content. Leaves of a mutant `Ailsa Craig', containing the Never ripe mutation, did not exhibit epinasty but exhibited the same amount of reduced chlorophyll concentration and starch content as normal plants. Leaves of a transgenic `Ailsa Craig', containing an antisense gene of 1-aminocyclopropane 1-carboxylate (ACC) oxidase, were epinastic, but chlorophyll concentration and starch content were greater than in leaves of normal and mutant plants. These results suggest that transgenic plants were more tolerant of constant light than the other genotypes. Evidence from these studies indicates that ethylene, combined with constant light, has an important role in the development of constant-light injury.

EFFECTS OF CONTINUOUS LIGHT ON THE REPRODUCTIVE CYCLE OF THE FEMALE RAT: INDUCTION OF OVULATION AND PITUITARY GONADOTROPHINS DURING PERSISTENT OESTRUS

1967 ◽  
Vol 38 (4) ◽  
pp. 389-394 ◽  
Author(s):  
K. B. SINGH ◽  
G. S. GREENWALD
Keyword(s):  
Luteinizing Hormone ◽  
Single Injection ◽  
Follicle Stimulating Hormone ◽  
Continuous Light ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
The Other ◽  
Constant Light ◽  
Female Rat ◽  
Control Light

SUMMARY The majority of rats exposed to constant light for approximately 6 weeks ovulated within 24 hr. after an injection of human chorionic gonadotrophin (HCG), but required 24–48 hr. after a single injection of progesterone. This suggests that HCG acted directly on the ovary but that progesterone acted indirectly by way of the hypothalamo-hypophysial system. Animals injected with progesterone after 6 weeks of constant light failed to ovulate after single or spaced injections of progesterone at 90 days of constant light while HCG administration was still effective. Pituitary content and concentration of luteinizing hormone (LH) in constant-light animals (duration of constant light: 45 days) were below normal pituitary levels during prooestrus and were in the range of normal oestrous values. On the other hand, follicle-stimulating hormone (FSH) content and concentration were similar to those in cyclic rats. Single injections of 1 mg. progesterone changed neither LH nor FSH concentration, despite the fact that such treatment induced ovulation. Bilateral ovariectomy increased both LH and FSH content and concentration in constant-light animals to the same extent as in control light—dark animals.

Prior Exposure To Light and Pecking Accuracy in Chicks

Behaviour ◽  
1975 ◽  
Vol 52 (3-4) ◽  
pp. 196-201 ◽  
Author(s):  
J. Vauclair ◽  
P.P.G. Bateson
Keyword(s):  
White Light ◽  
Visual Pathways ◽  
The Other ◽  
Prior Exposure ◽  
Domestic Chicks ◽  
Millet Seed ◽  
Socially Isolated ◽  
Specific Stimulation ◽  
Light Group ◽  
Stimulation Of

AbstractTwo groups of day-old domestic chicks were exposed to constant white light for one hour. Chicks in one group were socially isolated but unrestrained; the others were unable to move their heads. Later the accuracy of their pecking at millet seed was compared with chicks kept in the dark up to the time of testing. The unrestrained chicks exposed to light were markedly more accurate than the dark-reared birds. The restrained chicks were intermediate in performance between the other two groups hitting seeds more frequently than the dark group but missing more and picking up and swallowing less than the unrestrained Light group. The effects of light on pecking accuracy are interpreted primarily in terms of non-specific stimulation of the visual pathways.

Visual Persistence as Measured by Reaction Time

1972 ◽  
Vol 24 (3) ◽  
pp. 318-325 ◽  
Author(s):  
Gary G. Briggs ◽  
Marcel Kinsbourne
Keyword(s):  
Reaction Time ◽  
Power Function ◽  
Stimulus Duration ◽  
Visual Display ◽  
Visual Persistence ◽  
The Other ◽  
Reaction Time Measure

Latency of reaction to onset of a visual display was subtracted from latency of reaction to offset. Persistence was defined as difference between the two latency values. Persistence was inversely related to stimulus duration and was comparable for monoptic presentation and for presentation of the first half of the stimulus duration to one eye and the second half to the other. A power function described the relation between persistence and stimulus duration. The possible effects of central intermittency on this type of reaction time measure are discussed.

Two-Part Stimulus Integration and Specific Reading Disability

1975 ◽  
Vol 41 (3) ◽  
pp. 873-874 ◽  
Author(s):  
Gordon Stanley
Keyword(s):  
Reading Disability ◽  
Significant Interaction ◽  
Visual Persistence ◽  
The Other ◽  
Specific Reading Disability ◽  
Specific Reading ◽  
Black Cross ◽  
Interstimulus Intervals

29 dyslexics and 29 control children were presented with two halves of a black cross, one-half being presented at varying interstimulus intervals after the other half. Both dichoptic and binocular presentations were used and separation thresholds were at greater interstimulus intervals for the dichoptic condition. Dyslexics had thresholds at greater intervals than controls. These differences were significant and there was no significant interaction of group by dichoptic condition. The relative magnitudes of difference between dyslexics and controls were as previously reported by Stanley and Hall (1973) and support the notion that dyslexics have longer visual persistence than controls.

Stromatoporoids from the Famennian (Devonian) Wabamun Formation, Normandville oilfield, north–central Alberta, Canada

1988 ◽  
Vol 62 (03) ◽  
pp. 411-419 ◽  
Author(s):  
Colin W. Stearn
Keyword(s):  
Patch Reef ◽  
Abundant Species ◽  
The Other ◽  
North Central ◽  
Biotic Crisis

Stromatoporoids are the principal framebuilding organisms in the patch reef that is part of the reservoir of the Normandville field. The reef is 10 m thick and 1.5 km2in area and demonstrates that stromatoporoids retained their ability to build reefal edifices into Famennian time despite the biotic crisis at the close of Frasnian time. The fauna is dominated by labechiids but includes three non-labechiid species. The most abundant species isStylostroma sinense(Dong) butLabechia palliseriStearn is also common. Both these species are highly variable and are described in terms of multiple phases that occur in a single skeleton. The other species described areClathrostromacf.C. jukkenseYavorsky,Gerronostromasp. (a columnar species), andStromatoporasp. The fauna belongs in Famennian/Strunian assemblage 2 as defined by Stearn et al. (1988).

D. The Line Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 207-244
Author(s):  
R. P. Kraft
Keyword(s):  
Variable Stars ◽  
The Other ◽  
Line Spectrum ◽  
Afternoon Session ◽  
Empirical Information ◽  
Pulsating Variable Stars ◽  
Almost Continuous ◽  
Informal Approach

(Ed. note:Encouraged by the success of the more informal approach in Christy's presentation, we tried an even more extreme experiment in this session, I-D. In essence, Kraft held the floor continuously all morning, and for the hour and a half afternoon session, serving as a combined Summary-Introductory speaker and a marathon-moderator of a running discussion on the line spectrum of cepheids. There was almost continuous interruption of his presentation; and most points raised from the floor were followed through in detail, no matter how digressive to the main presentation. This approach turned out to be much too extreme. It is wearing on the speaker, and the other members of the symposium feel more like an audience and less like participants in a dissective discussion. Because Kraft presented a compendious collection of empirical information, and, based on it, an exceedingly novel series of suggestions on the cepheid problem, these defects were probably aggravated by the first and alleviated by the second. I am much indebted to Kraft for working with me on a preliminary editing, to try to delete the side-excursions and to retain coherence about the main points. As usual, however, all responsibility for defects in final editing is wholly my own.)

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

Observing programme for the 24-inch/36-inch Schmidt telescope

1966 ◽  
Vol 24 ◽  
pp. 337
Author(s):  
W. Iwanowska
Keyword(s):  
The Other ◽  
Schmidt Telescope ◽  
Flint Glass

A new 24-inch/36-inch//3 Schmidt telescope, made by C. Zeiss, Jena, has been installed since 30 August 1962, at the N. Copernicus University Observatory in Toruń. It is equipped with two objective prisms, used separately, one of crown the other of flint glass, each of 5° refracting angle, giving dispersions of 560Å/mm and 250Å/ mm respectively.

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