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61.
Gutiérrez G. de Guzmán I. P. Martínez J. Ojeda-Aciego M. Valverde A. 《Studia Logica》2002,72(1):85-112
The tree-based data structure of -tree for propositional formulas is introduced in an improved and optimised form. The -trees allow a compact representation for negation normal forms as well as for a number of reduction strategies in order to consider only those occurrences of literals which are relevant for the satisfiability of the input formula. These reduction strategies are divided into two subsets (meaning- and satisfiability-preserving transformations) and can be used to decrease the size of a negation normal form A at (at most) quadratic cost. The reduction strategies are aimed at decreasing the number of required branchings and, therefore, these strategies allow to limit the size of the search space for the SAT problem. 相似文献
62.
Petr Hájek 《Studia Logica》2002,71(2):149-164
63.
Jezová D Skultétyová I Makatsori A Moncek F Duncko R 《Stress (Amsterdam, Netherlands)》2002,5(3):177-183
Neuroendocrine activation during stress is affected by many factors contributing to the variability of the stress response. The present study was aimed at evaluating long-term changes in hypothalamo-pituitary-adrenocortical (HPA) axis function and in hedonic behavior in adult offspring prenatally stressed by maternal food restriction, with attention on possible gender differences. Adult offspring were blood sampled via a tail artery cannula. Prenatally stressed females had significantly higher adrenal weights compared to males. Plasma ACTH levels, which rose in response to acute stress induced by handling, were significantly higher in females compared to those in males. A similar pattern was found in plasma corticosterone. The rise in ACTH levels was more pronounced in prenatally stressed rats though the rise in corticosterone failed to be modified. Corticotropin releasing hormone (CRH) and proopiomelanocortin mRNA levels in the hypothalamic paraventricular nucleus and anterior pituitary, respectively, were found to be unchanged. The present experiments failed to reveal a decrease in hedonic behavior in prenatally stressed rats. In contrast, in male offspring a tendency to a higher sucrose preference was observed. These data together with observed changes in hormone and CRH mRNA levels indicate that the gestational stress used did not result in a depression-like state in adult offspring. 相似文献
64.
The positive effect of postlearning sleep on memory consolidation as well as the relationship between sleep-related memory processes and the hippocampal formation are increasingly clarified topics in neurobiology. However, the possibility of a stable relationship between waking mnemonic performance and sleep-dependent hippocampal electric activity is unexplored. Here we report a correlative analysis between sleep-dependent parahippocampal-hippocampal (pHip-Hip) electric activity recorded by foramen ovale (FO) electrodes and different types of memory performances in epileptic patients. Psychological testing was performed days or weeks before electrophysiological recordings. The relative spectral power of the slow activity (below 1.25 Hz) during deep non-REM (NREM) sleep at the right pHip-Hip region correlated positively with the visual memory performance according to Rey-Osterrieth Complex Figure Test (ROCFT). Along the posterior-anterior direction of the hippocampal formation a linear increasing of correlations was observed. The relative power of the activity below 1.25 Hz at the left pHip-Hip during phasic REM sleep correlated positively with verbal learning performance and mnemonic retention values according to ROCFT. It is concluded that the pHip-Hip structures' capacity of producing high amplitude and synchronized slow (< 1 Hz) oscillation during deep NREM sleep is related to the functional power of these structures. We hypothesize that the asymmetric (side-specific) propagation of ponto-geniculo-occipital (PGO) activity to the pHip-Hip region is related to the memory correlates of phasic REM sleep. 相似文献
65.
Attending, ignoring, and repetition: on the relation between negative priming and inhibition of return 总被引:8,自引:0,他引:8
A series of spatial localization experiments is reported that addresses the relation between negative priming and inhibition of return. The results of Experiment 1 demonstrate that slowed responses to repeated location stimuli can be obscured by repetition priming effects involving stimulus dimensions other than spatial location. The results of Experiments 2, 3A, and 3B demonstrate that these repetition priming effects may occur only when participants are required to respond to the prime display. Together, these results suggest that differences between attended and ignored repetition effects in selective attention studies of spatial localization do not provide a basis for distinguishing between spatial negative priming and inhibition of return. 相似文献
66.
Revisiting the constraint attunement hypothesis: reply to Ericsson, Patel, and Kintsch (2000) and Simon and Gobet (2000) 总被引:2,自引:0,他引:2
Vicente KJ 《Psychological review》2000,107(3):601-608
This article is part of an exchange concerning the contributions of the constraint attunement hypothesis (CAH) to the understanding of expertise effects in memory recall. K. A. Ericsson, V. Patel, and W. Kintsch (2000) and H. A. Simon and F. Gobet (2000) claim that the CAH is not novel and that existing theories of this phenomenon do not have the limitations that were attributed to them. In this reply, the CAH is argued to be the only theory of expertise effects in memory recall to adopt the abstraction hierarchy as a theory of the environment, a feature that has important theoretical implications. Also, other theories focus on psychological mechanisms but have not satisfied the burden of scientific proof required of process theories. Progress can be made by integrating the complementary advantages of existing theories into a unified theory that acknowledges the equally important roles of the organism and the environment. 相似文献
67.
A comparative analysis was conducted of five different methods for scoring the Rod-and-Frame Test to examine the convergent validities of each of the five methods with performance on the Embedded Figures Test for a sample of 408 13- to 16-yr.-olds. The scoring methods included the absolute error, the algebraic error, the absolute value of the algebraic error, the frame effect, and an assessment of relative field dependence. Correlations obtained among the five methods and the Embedded Figures Test indicated different patterns for boys and girls. In general, the method which employed the absolute value of the algebraic error yielded the strongest convergent validity coefficients with scores on the Embedded Figures Test and Group Embedded Figures Test for boys (.62 and -.54, respectively), although, for girls, the absolute algebraic error and absolute error both yielded coefficients of .50 with Embedded Figures Test scores and -.46 with Group Embedded Figures Test scores. 相似文献
68.
In search of remembrance: evidence for memory in visual search 总被引:2,自引:0,他引:2
Kristjánsson A 《Psychological science》2000,11(4):328-332
Observers searched for a target among distractors while the display items traded places every 110 ms. Search was slower when the target was always relocated to a position previously occupied by a distractor than when the items remained in place, showing the importance of memory for locations in a visual search task. Experiment 2 repeated a previous study in which items could move to any location within the display, but used a larger range of set sizes than tested in the earlier study. A cost in search times to relocating items was found at the larger set sizes, most likely reflecting that the probability that the target would replace a distractor increased witht he set size. The findings provide strong evidence for the role of memory for locations within trials in a visual search task. 相似文献
69.
The purpose of this study was to identify factors associated with early onset of sexual intercourse. Within an ecological system's conceptual framework, familial factors associated with early onset of sexual activity were identified in a sample of 425 adolescents from San Juan metro area schools. Measures included questions about sexual activity, sexual permissiveness, and such familial variables as: discipline, parental supervision, and parental support. Significant relationships were observed between early onset of sexual intercourse and parental supervision, discipline, parental support, and parents' marital status. Results suggest the key role of parents and family in prevention of HIV-risk behaviors among adolescents in terms of delaying sexual onset. Overall, the study described youths who postponed sexual activity as having greater support, supervision, and parental involvement. 相似文献
70.
The structure of goal contents across 15 cultures 总被引:4,自引:0,他引:4
Grouzet FM Kasser T Ahuvia A Dols JM Kim Y Lau S Ryan RM Saunders S Schmuck P Sheldon KM 《Journal of personality and social psychology》2005,89(5):800-816
The authors investigated the structure of goal contents in a group of 1,854 undergraduates from 15 cultures around the world. Results suggested that the 11 types of goals the authors assessed were consistently organized in a circumplex fashion across the 15 cultures. The circumplex was well described by positioning 2 primary dimensions underlying the goals: intrinsic (e.g., self-acceptance, affiliation) versus extrinsic (e.g., financial success, image) and self-transcendent (e.g., spirituality) versus physical (e.g., hedonism). The circumplex model of goal contents was also quite similar in both wealthier and poorer nations, although there were some slight cross-cultural variations. The relevance of these results for several theories of motivation and personality are discussed. 相似文献