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Felipe Minozzo Carlos Leonardo Figueiredo Machado Eurico Nestor Wilhelm Rafael Grazioli Ronei Silveira Pinto 《European Journal of Sport Science》2018,18(10):1398-1404
Isokinetic hamstring-to-quadriceps (H:Q) ratios are frequently used to assess knee muscle strength imbalances and risk of injuries/re-injuries. The use of peak torque (PT) or total work (TW) to estimate joint stability may lead to different results because of the differences between these two neuromuscular variables. Thus, the current study aimed to compare the conventional and functional H:Q ratios calculated by PT and TW. Ninety-three male professional soccer players from Brazilian first division teams performed isokinetic concentric and eccentric contractions of the quadriceps and the hamstrings at 60°/s. Muscle strength balance was calculated using the conventional torque ratio (CTR) and conventional work ratio (CWR), functional torque ratio (FTR) and functional work ratio (FWR) were highly and moderately correlated between them (r?=?0.83 and r?=?0.73, respectively). The Wilcoxon statistical test revealed significant differences between CTR and CWR, as well as FTR and FWR (p?T-test demonstrated significant differences in mean CTR–CWR and FTR–FWR, whereas Bland–Altman plots showed non-consistent bias. In addition, the chi-square test demonstrated significant differences between players below the conventional reference values and functional reference values (p?相似文献
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This article introduces a new "real-time" model of classical conditioning that combines attentional, associative, and "flexible" configural mechanisms. In the model, attention to both conditioned (CS) and configural (CN) stimuli are modulated by the novelty detected in the environment. Novelty increases with the unpredicted presence or absence of any CS, unconditioned stimulus (US), or context. Attention regulates the magnitude of the associations CSs and CNs form with other CSs and the US. We incorporate a flexible configural mechanism in which attention to the CN stimuli increases only after the model has unsuccessfully attempted learn input-output combinations with CS-US associations. That is, CSs become associated with the US and other CSs on fewer trials than they do CNs. Because the CSs activate the CNs through unmodifiable connections, a CS can become directly and indirectly (through the CN) associated with the US or other CSs. In order to simulate timing processes, we simply assume that a CS is formed by a temporal spectrum of short-duration CSs that are activated by the nominal CS trace. The model accurately describes 94?% of the basic properties of classical conditioning, using fixed model parameters and simulation values in all simulations. 相似文献
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In the present special issue, the performance of current computational models of classical conditioning was evaluated under three requirements: (1) Models were to be tested against a list of previously agreed-upon phenomena; (2) the parameters were fixed across simulations; and (3) the simulations used to test the models had to be made available. These requirements resulted in three major products: (a) a list of fundamental classical-conditioning results for which there is a consensus about their reliability; (b) the necessary information to evaluate each of the models on the basis of its ordinal successes in accounting for the experimental data; and (c) a repository of computational models ready to generate simulations. We believe that the contents of this issue represent the 2012 state of the art in computational modeling of classical conditioning and provide a way to find promising avenues for future model development. 相似文献
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Anastasios J. Sakalis Nikolaos A. Kazakis Nikolaos Merousis Nestor C. Tsirliganis 《Journal of Cultural Heritage》2013,14(6):485-498
Various types of Late Neolithic decorated pottery excavated in Polyplatanos (Imathia, Greece) such as Crusted (C), Classical Dimini (CD), Black-on-Red (BoR), Cream-on-Red (CoR) and Graphite (G) were archaeometrically studied in order to investigate their provenance and to clarify specific technological features. The clay bodies, the paints and the slips were stereoscopically analyzed, while their elemental composition was determined, using non-destructive multi-elemental micro X-ray fluorescence spectroscopy. Furthermore, the analytical data were statistically treated using multivariate exploratory techniques (Principal Component Analysis, PCA). As a result, novel technological information was derived especially concerning the Crusted type ceramics, which have not been widely examined by archaeometric means up to now, while useful provenance associations were also derived from the statistical combination of the studied groups. 相似文献
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An attentional-associative model (Schmajuk, Lam, & Gray Journal of Experimental Psychology: Animal Behavior Processes, 22, 321–349, 1996) assumes that nonreinforced presentations of an inhibitory conditioned stimulus (CS) do not decrease its inhibitory associations.
However, the model predicts that extended presentations will decrease attention to the inhibitor, thereby decreasing both
(1) the expression of its inhibitory power in a summation test and (2) the rate of acquisition in a retardation test. The
model also predicts that subsequent presentations of the inhibitory CS with a novel CS will increase both (1) and (2). Using
a predictive learning design in humans, Experiment 1 examined the predictions involving the summation tests, whereas Experiments 2 and 3 examined the predictions involving the retardation tests. Experimental results were in agreement with the predictions of
the model. 相似文献