RESUMO
In this present paper, we showed that wavelet analysis (WA) has the potential for extracting specific features from measured arterial diameter and pressure waveforms. The fifth detail of the Daubechies 4 (Db4) wavelet appears to be the most appropriate level for application, in order to analyze artery waveforms and was used to characterized arterial de-endothelization (DE). Raises in smooth muscle tone induced by (DE) tended to increase arterial stiffness and therefore that WA details embed the information of the diameter and pressure pulse that contains the signature of effects of wave travel and reflection affected by arterial stiffness.
Assuntos
Artérias/anatomia & histologia , Artérias/fisiologia , Determinação da Pressão Arterial/métodos , Pressão Sanguínea/fisiologia , Diagnóstico por Computador/métodos , Embolização Terapêutica , Endotélio Vascular/anatomia & histologia , Endotélio Vascular/fisiologia , Análise de Ondaletas , Animais , Artérias/cirurgia , Endotélio Vascular/cirurgia , Masculino , OvinosRESUMO
The response time to judge the order relationship between two symbolic stimuli is frequently modeled as the time spent in a (constant-rate) accumulative sampling process until a threshold is reached. We will show that empirical descriptions of observed effects in number comparisons suggest an accrual process that reaches the threshold at an exponential rate. The model accrual equations and stopping conditions have an immediate interpretation in terms of a simple quantitative connectionist network. The encoded stimuli and thresholds are inputs to the network. The former are considered to result from the participant's learning history, and the latter modulate the rearrangement of the network parts; each arrangement models a different task. We have found a good correlation between model predictions and other authors' experimental data, both in number comparisons and in experiments in which the ordering of the symbolic stimuli has been artificially induced. Incorrect answers are discussed, and predictions are compared with data. We will explore differences and similarities with other approaches, such as random walk and the symbolic comparison model. In a limit case, our model becomes identical to the discriminability model.
Assuntos
Julgamento , Tempo de Reação , Simbolismo , Humanos , Modelos Psicológicos , Percepção VisualRESUMO
Passive diffusion samplers were employed in San Miguel (Buenos Aires Metropolitan Area) for a preliminary air pollution monitoring. The highest loads were observed in downtown, compared with an urban background site. Total suspended particulate matter (TSPM) varied from 0.257 to 0.033 mg cm(-2) month(-1); dust was examined for particle nature and size distribution. A similar trend was observed for nitrogen dioxide (NO2) and TSPM spatial distribution, suggesting that traffic is the major pollution source. Sulphur dioxide (SO2) values were low and rather homogeneous. Levels for the investigated pollutants are below EPA's guide line values. Geographic (flat area, near to Rio de La Plata) and climatologic factors (rainfalls and variable wind directions) contribute to disperse pollutants.