Search results for "SYSTEMS"
showing 10 items of 11952 documents
Dynamic accommodation without feedback does not respond to isolated blur cues
2016
Highlights • A new methodology is used to study a potential cue for dynamic accommodation. • We show that human accommodation is not driven correctly by defocus alone. • Accommodation is most efficient using changes in stimulus vergence with feedback.
The effect of longitudinal chromatic aberration on the lag of accommodation and depth of field.
2016
Purpose Longitudinal chromatic aberration is present in all states of accommodation and may play a role in the accommodation response and the emmetropisation process. We study the change of the depth of field (DOFi) with the state of accommodation, taking into account the longitudinal chromatic aberration. Methods Subjective DOFi was defined as the range of defocus beyond which the blur of the target (one line of optotypes of 0.1 logMAR shown on a black-and-white microdisplay, seen through different colour filters) was perceived as objectionable. The subject's eye was paralysed and different, previously-measured accommodative states (corresponding to the accommodative demands of 0D, 2D and …
Measuring and modeling real-time responses to music: the dynamics of tonality induction.
2003
We examined a variety of real-time responses evoked by a single piece of music, the organ Duetto BWV 805 by J S Bach. The primary data came from a concurrent probe-tone method in which the probe-tone is sounded continuously with the music. Listeners judged how well the probe tone fit with the music at each point in time. The process was repeated for all probe tones of the chromatic scale. A self-organizing map (SOM) [Kohonen 1997 Self-organizing Maps (Berlin: Springer)] was used to represent the developing and changing sense of key reflected in these judgments. The SOM was trained on the probe-tone profiles for 24 major and minor keys (Krumhansl and Kessler 1982 Psychological Review89 334–…
Reliability and factor structure of the Finnish version of the Sport Imagery Questionnaire.
2006
The aim of this study was to examine the reliability and factor structure of the Finnish version of the Sport Imagery Questionnaire, a measure which examines cognitive and motivational functions of imagery. The final sample comprised 231 participants drawn from 34 sports and ranging in age from 14 to 49 years ( M = 20.9, SD= 5.8). Internal consistency and confirmatory factor analyses were undertaken to evaluate the reliability and factorial validity of the scale. Fit indices and modification data generated from examining the 30-item five-factor model were equivocal, suggesting minor amendment and recategorization of several items rather than major adjustment to the proposed latent factor s…
Event-Related Potentials and Autonomic Responses to a Change in Unattended Auditory Stimuli
1992
Event-related brain potentials (ERPs) and autonomic nervous system (ANS) responses to occasional pitch and rise-time changes in a task-irrelevant auditory stimulus repeating at short intervals were measured while the subject performed a difficult intellectual task (Raven Matrices). It was found that deviant stimuli elicited the mismatch negativity (MMN) component of the ERP even when they elicited no ANS response. There was no significant difference in the mismatch negativity between trials in which the skin conductance response was or was not elicited. The pitch deviant tone also elicited heart rate deceleration, whereas the rise-time deviant tone tended to elicit a later heart rate accele…
Influence of cognitive-motor expertise on brain dynamics of anticipatory-based outcome processing.
2019
Motor experience plays an important role in the ability to anticipate action outcomes, but little is known about the brain processes through which it modulates the preparation for unexpected events. To address this issue, EEG was employed while table tennis players and novices observed videos of serves in order to predict the expected ball direction based on the kinematics of a model's movement. Furthermore, we manipulated the congruency between the model's body kinematics and the subsequent ball trajectory while assessing the cerebral cortical activity of novices and experts to understand how experts respond to unexpected outcomes. Experts were more accurate in predicting the ball trajecto…
The time course of orthography and phonology: ERP correlates of masked priming effects in Spanish
2009
Abstract One key issue for computational models of visual-word recognition is the time course of orthographic and phonological information during reading. Previous research, using both behavioral and event related brain potential (ERP) measures, has shown that orthographic codes are activated very early but that phonological activation starts to occur immediately afterward. Here we report an ERP masked priming experiment in Spanish that investigates this issue further by using very strict control conditions. The critical phonological comparison was between two pairs of primes having the same orthographic similarity to the target words but differing in phonological similarity (e.g., conal-CA…
A BRIEF NOTE ON THE RELATIONSHIP BETWEEN ANXIETY AND PERFORMANCE IN SCUBA DIVING IN ADOLESCENTS: A FIELD STUDY.
2015
This study explored the relationship between anxiety and scuba diving performance of young individuals ( N = 44; 16.9yr., SD = 1.2) participating in an introductory scuba diving activity. The question was whether the well-known negative correlation between anxiety and scuba diving performance found for experienced and middle-aged scuba divers will be observed in young participants in their first dive experience. Diving instructors rated standardized scuba diving skills that were correlated with individual state and trait anxiety. There was no relationship between anxiety and scuba diving performance, neither for state nor for trait anxiety. This non-significant correlation between anxiety …
Gentamicin, norfloxacin and lysozyme concentration in human tears: in vivo and in vitro study
1992
Hen's egg lysozyme (HEL) activity was measured in vitro with gentamicin and norfloxacin by a turbidimetric technique. Gentamicin at the concentration of 10(-3) M inhibited HEL activity by 39%, while 10(-3) M norfloxacin did not affect HEL activity. However, an in vivo study in healthy persons did not show any significant statistical difference in tear lysozyme activity when 0.3% gentamicin or 0.3% norfloxacin were topically applied.
Illusory contours from pictorially three-dimensional inducing elements: counterevidence for Parks and Rock's example.
1993
In 1990 Parks and Rock claimed that, in pictorially three-dimensional (3-D) inducing patterns, an illusory figure does not emerge if a clear occlusion event is not present. A new pictorially 3-D pattern is presented which contradicts this claim. Two experiments were carried out. The first was aimed at ascertaining the presence of an illusory figure in the new 3-D pattern; the second was aimed at offering evidence that in Parks and Rock's pattern the disappearance of the illusory figure could be due to local interferences caused by the line elements in contact with the inducing borders. The results tend to contradict Parks and Rock's conclusions.