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Information about the intent to emigrate was collected for a sample of 960 adolescents living in the northern region of Portugal. This question was part of a detailed questionnaire designed to assess specific issues concerning social representations of migration-namely, information, attitude, and fields of representation. Using information about the sociodemographic characteristics and the components of social representation mentioned above, our aim was to identify the independent predictors underlying the adolescent's intent to emigrate. Due to the great number of factors involved in the analysis, we conducted a preliminary selection of independent predictors within each of the aforementioned components and created a global index describing their importance. The findings indicate that, among all components of a social representation, attitude and representation of detachment and adaptation are the most important predictors of intent to emigrate. The relatively poor ability of sociodemographic variables to predict a future emigration does not mean that they are not important, but rather that they are more likely to condition attitude, the strongest predictor of a future emigration in the northern region of Portugal. The implication of these findings for handling intervening migration policies is discussed.  相似文献   
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ABSTRACT It has been hypothesized that individuals who are high on the attribute of self-criticism are particularly vulnerable to failure stress. To test this hypothesis, we examined the relationship between self-criticism and changes in plasma homovanillic acid (HVA; the metabolite of dopamine) and emotion during exposure to an induced-failure task. Participants consisted of 21 women. Plasma HVA and emotion were assessed at three time points: baseline (T1), during stress exposure (T2), and 40 minutes after cessation of the stressor (T3). We found that self-criticism was significantly and positively related to changes in plasma HVA during stress exposure. In addition, the personality attribute was significantly and positively related to subjective ratings of stress and changes in scores on the Confusion-Bewilderment scale of the Profile of Mood States during the task. To our knowledge, this is the first study to report that self-criticism is related to stress-induced changes in biochemistry.  相似文献   
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In the behavior systems view, a long CS–US interval should differentially condition a general search mode and related behavior, while a short CS–US interval should differentially condition a focal search mode and related behavior. Two experiments paired a long or a short CS with food, and then, during an extinction test, compounded the CS with an unconditioned probe-stimulus of a rolling ball-bearing. Presuming that the long CS differentially conditions a general search mode, and that unconditioned contact of a moving stimulus is characteristic of that mode, presentation of the long CS should facilitate interaction with the ball-bearing. Similarly, presuming that a short CS differentially conditions a focal search mode, and that feeder-directed responses are characteristic of this mode, presentation of a short CS should facilitate nosing in the food-tray. Consistent with these predictions, ball-bearing contact increased in rats receiving the long CS, while nosing in the food-tray was higher with the short CS.  相似文献   
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Fourier analysis describes the amount of variation in a time series by partitioning it into sinusoids of different amplitudes and wavelengths and quantifying the extent to which these waves are synchronized. The importance of a given wave is represented by its contribution to the explained variance of the time series. To illustrate its potential application to the study of movement, Fourier analysis was used to quantify the movement patterns of 2 pigeons on a variable-interval (VI) and a variable-time (VT) schedule of reinforcement. For comparison, the movements of 2 pigeons that did not receive reinforcement were similarly analyzed. Characteristic frequencies were higher during VI than during VT, and relatively low during nonreinforcement. We concluded that Fourier analysis can be used to represent movement patterns compactly, study their periodicity, stereotypy, and resonance, and assist in computer simulations and models of movement.  相似文献   
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Judged distance in a large open field, scaled by the method of magnitude estimation, is related to physical distance by a power function with an exponent smaller than unity. The exponents obtained with two ranges of distance were not affected by the availability of a standard. The mean exponent for all 80 individual power functions was 0.86, with a standard deviation of 0.11.  相似文献   
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Several studies have shown a negative linear relationship between speech rate and memory span. This relationship has implications for bilingual studies, as span could be larger in a bilingual's secondary language provided that pronunciation rate is faster than in the mother language. The purpose of this study was to investigate the effects of digit word length on digit span in bilinguals. Experiment 1 tested the effects of digit syllable length on speech rate in five different bilingual groups. Results revealed that digit-reading rates were significantly faster in all mother languages. Experiment 2 examined more closely the correspondence between speech rate and digit span with Portuguese-English bilinguals. Results showed that digit-reading rates were faster and digit span larger in the mother language even if the mean number of syllables per digit was higher. The superiority of mother tongue was discussed according to the view that digits are subject to massive practice in one's native language with a strong tendency to be abbreviated, thus reducing its spoken duration.  相似文献   
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This study investigated the relationship between manifest handedness and the localization of EEG abnormalities in a large group of mentally retarded persons. Persons who had abnormal EEG recordings, regardless of whether the dysfunction was bilateral or asymmetric, exhibited approximately twice the incidence of left-handedness than persons who had normal EEG's. Data for persons having asymmetric damage support a model of pathological left-handedness, with left-handers showing a substantially higher probability of having left brain dysfunction than right-handers.  相似文献   
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The automatic skeletal motor responses of 20 male and 20 female student subjects (aged 20–36) receiving a painful stimulation (electric shock) were studied by examining voluntary concomitant extensions and flexions of the arm. These movements were either of long duration, allowing for an on-line control of their execution or, of short duration, requiring extensive pre-programming. Subjects were instructed either to push or to pull a lever upon receipt of an acoustic signal, which was paired or unpaired with an electric shock. Latencies for long duration movements (regardless of direction) were reduced by reception of painful stimulation. Latencies of short duration extensions and flexions were respectively reduced and increased by painful stimulation. Latencies of short duration movements were larger for females than males, regardless of movement direction. These data suggest that painful stimulation elicits automatic movements which affect programming of the termination of simultaneous voluntary movements. Implications of these findings for the study of aggressive behavior are discussed. © 1994 Wiley-Liss, Inc.  相似文献   
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