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71.
Dynamic retinoscopy has suggested that near vision may be more acute than far vision during early infancy. To test this, acuity thresholds were determined by presenting square wave gratings in a preference paradigm to 1- and 2-month-old human infants at 4 viewing distances. Gratings were paired with unpatterned fields; direction of first fixation was the dependent measure. Infants exhibited the same acuity at each of the distances at which gratings were presented. The results were interpreted as compatible with the fact that considerable optical defocusing does not seriously affect a visual system, such as the infant's, that is sensitive only to low spatial frequencies.  相似文献   
72.
The chief purpose of this study was to identify characteristics that distinguish approach as an attachment behavior from approach serving other behavioral systems. Locomotor approaches of 16 male and 10 female white middle-class infants to an attachment figure (the mother) and to a nonattachment figure (the visitor-observer) were examined under naturalistic conditions at home. Observations were made during 4-hour home visits at 3-week intervals; those from 26 to 54 weeks were used. When approach was examined in a free-choice situation and without regard to behavioral context, infants approached the mother proportionally (though slightly) more often than the visitor (p less than .05). In 2 behavioral contexts, however, spontaneous infant approaches were sharply differential to the mother; approaches accompanied by crying and approaches terminating in a pickup appeal were directed almost exclusively to the mother (p less than .0001 for both). Touching upon completion of the approach was not differential, except in the context of a pickup appeal. Object-oriented approaches were more often directed to the visitor than to the mother (p less than .002) and may be either exploratory or affiliative. It is suggested that neither approach nor touching can be assumed to serve the attachment system without consideration of context- both environmental and behavioral.  相似文献   
73.
48 healthy neonates born to multiparae were randomly assigned to view a moving stimulus either in the horizontal or the upright position, with or without added vestibular stimulation and with or without pacifier sucking. The infant was shown a moving black line inside a strictly controlled visual environment provided by an apparatus which permitted horizontal and upright positioning and displacement of the infant. Visual tracking was recorded by a concealed TV camera positioned at a constant distance and angle from the infants' eyes in both positions. Quality of tracking during each of 4 trials was scored on a 7-point scale. Results indicate that vestibularproprioceptive stimulation provided to the infant either horizontally or semivertically significantly enhanced his visual tracking, whereas the upright position did not. Pacifier sucking also improved his performace.  相似文献   
74.
75.
First-grade males performed a 30-min visual vigilance task under 5 conditions of auditory background stimulation. The 5 conditions consisted of (1) continuous conversation, in which subjects listened to a tape of conversation spliced so that there were no intervals of silence lasting longer than 3 sec; (2) continuous reverse, in which subjects heard the continuous conversation tape played in reverse; (3) intermittent conversation, in which subjects heard alternating segments of conversation and silence; (4) intermittent reverse, in which subjects heard alternating segments of reverse conversation and silence; and (5) silence control. Compared with silence or continuous stimulation, intermittent stimulation produced better detection regardless of whether or not it was meaningful. High achievers made more correct detections than low achievers, but only in the second and third time periods. Few subjects made errors of commission.  相似文献   
76.
The research reported in this article was carried out as part of a larger prefect investigating the impact of the US Space Program on the American economy. The author describes the influence of governmental programs in space and defense on the growth of the computer and semiconductor industries. Three types of economic impacts are analyzed: the role of the federal government in financing research and development; the importance of the government as a market, particularly in the early stages of an industry's growth; and the extent to which government policy encouraged the entrance of new firms and permitted the survival of companies that might otherwise have failed. The paper also deals with the contribution of Defense and NASA to the acceleration of technological changes and the development of specialized manpower on which the progress of the industry largely depended.The author concludes that large government programs can play an essential role in the growth of high technology industries. The significance of space-defense programs for US semiconductor and computer firms can only be perceived by reviewing each type of impact-economic, technological and manpower. The government's early R & D support, assured demand during startup periods, encouragement of competition, acceleration of technological progress and its facilitating of professional mobility, are the separate impacts which together greatly aided US firms in their rise to a dominant position in the world semiconductor and computer industries.  相似文献   
77.
Second graders, fifth graders, and adults participated in 2 experiments designed to study the effects of sorting on subsequent recall of unrelated words. 1 group sorted the items freely, while a second group was constrained to learn the sorting schemes generated by free subjects. In the first experiment, subjects sorted until they reached a criterion of organizational stability. In Experiment 2, sorting was terminated prior to reaching a stable criterion. Recall and output clustering were reduced in Experiment 2, relative to Experiment 1, because of organizational instability. No meaningful differences were found in either experiment in the sorting schemes generated by free subjects in the 3 age groups, nor was there an effect of age of yoking partner on performance of constrained subjects. This result differed from previous research, and it was concluded that the sorting technique diminished differences in organizational behavior usually found between older and younger subjects.  相似文献   
78.
The behavior of narcotics-addicted and nonaddicted newborns on the first 2 days of life was assessed with the Brazelton Neonatal Behavioral Assessment Scale. In addition to classic signs of narcotics abstinence, addicted infants were less able to be maintained in an alert state and less able to orient to auditory and visual stimuli. These deficits were especially pronounced at 48 hours of age. Addicted infants were as capable of self-quieting and responding to soothing intervention as normal neonates, although they were substantially more irritable. These characteristics and addicted infants' greater resistance to cuddling are discussed in terms of their potential impact on early infant-care-giver interaction.  相似文献   
79.
A mathematical theory is developed for an imagined device termed a “junctor”. A junctor could be used to interconnect two n-terminal networks giving rise to another n-terminal network. Actually a junctor is itself a simple network with three banks of n-terminals internally connected in some fashion by perfectly conducting wires. Adjacency matrices are formulated to analyze various junctors and their current flows. The main problem treated concerns conditions which would ensure that the junctor operation is associative.  相似文献   
80.
Part I provided an overview of PPBS, some discussion of PPBS implementation in the U.S. government, and a review of the arguments for adopting PPBS in postsecondary education and the various kinds of work that have been done toward this end. In part II, we discuss the experience of the University of California with PPBS from 1966 to 1971. Part III, to be published subsequently, will suggest some new departures in model construction and policy analysis which we believe represent a useful spirit in which further development can and should occur, and will also contain some general concluding observations.
Résumé Dans la première partie, publiée antérieurement, on trouvait les principes généraux du PPBS (Program Planning Budgeting Systems) une discussion rapide de la mise en oeuvre du PPBS par les autorités gouvernementals aux Etats-Unis, quelques uns des arguments qui militent en faveur de l'adoption du PPBS dans l'enseignement post-secondaire ainsi que ce qui a été entrepris à cette fin. Dans la deuxième partie, nous soumettons à la discussion ce qu'a été l'expérience de l'Université de Californie en matière de PPBS de 1966 à 1971. La troisième partie, qui sera publiée ensuite, proposera quelques points de départ nouveaux pour la construction du modèle directeur et l'analyse des politiques; nous pensons qui'il s'agit là d'un point de vue utilisable qui peut et devrait donner lieu à de nouveaux développements; cette troisième partie présentera aussi quelques observations générales en forme de conclusion.
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