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121.
Previous work had indicated that after prolonged exposure to a moving object, ducklings will direct filial responses toward that object even if it remains stationary during its presentation. The present experiment demonstrated the wide species generality of this effect by obtaining similar results in newly hatched chickens, pheasant, turkeys, and quail, as well as ducks.  相似文献   
122.
This article reports on a study in which an interactive computer‐based learning resource consisting of a tutorial with a decision support system and simulations, is evaluated in the context of a distance education business degree course. The primary purpose of the study was to develop and test an instrument for evaluation of the learning resource, with particular reference to simulations. The instrument adds further dimensions to factors such as learner support and engagement, to incorporate elements of motivation and transfer. Consequently, the scales that comprise the instrument include three key areas: features of the computer package, the effect on students” motivation, and the impact on their ability to transfer knowledge to the workplace. As a result of the analysis, a reliable and valid evaluation instrument that includes components of these three areas is provided. It is expected that other researchers will be able to develop and refine this instrument to evaluate various forms of computer‐based educational resources.  相似文献   
123.
In a recent paper Professor John Zeleny published curves obtained for ion mobilities at different ion ages in relatively pure N2 using his classical air blast method. Two features are of especial interest; one the apparent gradual displacement of the negative ion peak to lower mobilities as the ion age increases and the other a marked asymmetry of the electron peak on the low mobility side. This Zeleny interprets as an unresolved negative ion mobility of value about 100 cm./sec. per volt/cm. Such a mobility can only be explained by a carrier that is ion part of its life and electron part of its life, the electronic and ionic phases alternating frequently. The writers indicate that the latter interpretation cannot be correct on the basis of the energies and probabilities involved in electron attachment. Analysis shows that the whole series of the observed phenomena in N2 by this method are successfully accounted for on the proper application of the simplified theory of electron attachment to the air blast method. Since the attachment phenomena have to date not been applied to this type of mobility study it was felt of importance to present this analysis in order to guide future investigations by this method.  相似文献   
124.
The bearing of the recent results of Marshall on the theory of recombination of gaseous ions is discussed. It is shown, by solution of the Brownian movement equation for two ions of opposite sign, in a gas, that the average relative displacement in a time π is little influenced by the attractive forces, except for distances of the order of magnitude of 10?5 cm. or less, at ordinary temperatures. This conclusion, that in general the motion of the ions relative to each other is largely one of random diffusion, is in good agreement with the interpretation forced by Marshall's study of the variation of the coefficient of recombination α with time and concentration of ions. This also indicates that the theoretical approach of Langevin to the solution of the recombination problem is untenable, while that of Thomson is justified. The theory, of Thomson is discussed and, is compared with observation. It appears to fit qualitatively as accurately as the facts are known.It is then shown how the success of any theoretical treatment is limited due to our ignorance of the nature of the mass of the ion, a condition which, however, enables us to understand the very small range of variation of α among the different gases.  相似文献   
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The purpose of this experiment was to determine whether age differences in amounts of wheel running of starved rats were due to the frequency of bursts of running, to the average duration of bursts, to speed, or to any combination of these parameters. The experiment was carried out according to a 3 by 2 by 2 mixed model design. The independent variables were age (67, 293, and 746 days old at the start of starvation), food deprivation (total starvation vs ad lib), and occasion of measurement (initial vs maximum activity). The dependent variables were number of wheel revolutions, number of bursts of activity, number of seconds of running per burst, and revolutions per second. The results indicated that acutely starved rats run more often, for longer periods, and at higher speeds than do sated rats, and that with increased age rats run less often, for a shorter time, and at slower speeds.  相似文献   
130.
Siamese fighting fish (Betta splendens) were tested in aquatic versions of radial arm mazes. In the first experiment, the fish were trained to find tubifex worms in an eight-arm maze in which the optimal strategy was to choose each arm once without repetition. After initial training, the fish entered approximately 6.63 different arms in eight choices, showing a strong tendency to choose sequences of adjacent arms, moving about the maze in a Stereotypic direction. This algorithmic response pattern was not, however, sufficient to predict the high performance level of the fish. In the second experiment, a delay of .5 or 5 min was interposed between the fourth and fifth choices. Similar Stereotypic patterns continued in Experiment 2, but choice accuracy following the longer delay declined to a level not significantly above chance. In the third experiment, different fish were tested in a three-arm maze, reinforced either for returning from the second arm to the arm in which they had most recently been fed (win-stay) or for visiting a third arm (win-shift). The fish were significantly faster at acquiring the win-shift contingency than the win-stay contingency. These results demonstrate that solution of spatial tasks depends on the interaction of appropriate behavioral strategies and cognitive capacities that may have little generality across species.  相似文献   
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