scholarly journals Universal kinetics of imperfect reactions in confinement

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Thomas Guérin ◽  
Maxim Dolgushev ◽  
Olivier Bénichou ◽  
Raphaël Voituriez
Keyword(s):  
Reaction Time ◽  
Transport Process ◽  
Reaction Times ◽  
Complex Environments ◽  
Analytical Treatment ◽  
Volume Limit ◽  
Normal Diffusion ◽  
The Mean ◽  
Kinetics Of ◽  
Mean Reaction Time

AbstractChemical reactions generically require that particles come into contact. In practice, reaction is often imperfect and can necessitate multiple random encounters between reactants. In confined geometries, despite notable recent advances, there is to date no general analytical treatment of such imperfect transport-limited reaction kinetics. Here, we determine the kinetics of imperfect reactions in confining domains for any diffusive or anomalously diffusive Markovian transport process, and for different models of imperfect reactivity. We show that the full distribution of reaction times is obtained in the large confining volume limit from the knowledge of the mean reaction time only, which we determine explicitly. This distribution for imperfect reactions is found to be identical to that of perfect reactions upon an appropriate rescaling of parameters, which highlights the robustness of our results. Strikingly, this holds true even in the regime of low reactivity where the mean reaction time is independent of the transport process, and can lead to large fluctuations of the reaction time - even in simple reaction schemes. We illustrate our results for normal diffusion in domains of generic shape, and for anomalous diffusion in complex environments, where our predictions are confirmed by numerical simulations.

Effect of Visual Complexity in Identification of Tachistoscopic Images

1994 ◽  
Vol 78 (3) ◽  
pp. 971-978 ◽  
Author(s):  
Robert Geheb ◽  
Keith E. Whitfield ◽  
Linda Brannon
Keyword(s):  
Reaction Time ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Visual Complexity ◽  
Reaction Times ◽  
Right Cerebral Hemisphere ◽  
The Mean ◽  
The Times ◽  
The Right ◽  
Mean Reaction Time

The present study of gender differences in hemispheric processing involved identification of tachistoscopically presented images of varying complexity. A computerized tachistoscopic program was administered to 24 men and 34 women. Time to identify contour and detailed pictures presented to the left or right cerebral hemisphere was recorded. Mean reaction time for contour pictures was significantly faster than for detailed pictures, and mean reaction time to the right hemisphere was significantly faster than that to the left hemisphere. The mean reaction time for men to identify pictures exposed to the left hemisphere was significantly slower than that for exposure to the right hemisphere for women. The mean reaction time for both men and women to identify contour pictures exposed to the right hemisphere was significantly faster than the mean time to identify detailed pictures presented to the left hemisphere. The interaction of gender, hemisphere, and complexity was also significant in that mean reaction times for men to identify detailed pictures presented to the left hemisphere were slower than the times for women to identify contour pictures presented to the right hemisphere. The results are discussed in relation to theories about hemispheres, gender, and differences in picture features.

Evidence for Psychological Refractory Effect in Motor Inhibition for a Dual-Response Go/No-Go Task

1997 ◽  
Vol 85 (2) ◽  
pp. 563-568
Author(s):  
Miya Muroi ◽  
Eiichi Naito ◽  
Michikazu Matsumura
Keyword(s):  
Reaction Time ◽  
Human Subjects ◽  
Reaction Times ◽  
Motor Programming ◽  
Motor Inhibition ◽  
Motor Execution ◽  
Dual Response ◽  
Discrete Responses ◽  
The Mean ◽  
Mean Reaction Time

Human subjects exhibit difficulty in initiating two independent, discrete responses in close succession, a difficulty known as the ‘psychological refractory effect.’ It is not yet known whether motor-inhibition processes are under the influence of this effect, as are motor-execution processes. This study examined the temporal changes of subjects' reaction times, interpreted in terms of motor programming for inhibition, in a dual-response Go/No-Go task that required two independent responses in close succession Light subjects performed the task with both a shorter (400 msec.) and a longer interstunulus interval (800 msec). The mean reaction time for the second stimulus (RT2) in the Go response of the 400-msec. condition was significantly longer than that of the 800-msec. condition. For committed error responses during the No-Go trials, the mean RT2 in the 400-msec. condition was longer than that in the 800-msec. condition. The total number of these errors in the 400-msec. condition was significantly greater than that in the 800-msec. condition. These results suggested that both the motor-execution processes and motor-inhibition processes were influenced by the psychological refractory effect.

Reaction Time of the Fingers with Responses Measured on a Typewriter Keyboard

1978 ◽  
Vol 47 (3) ◽  
pp. 863-867 ◽  
Author(s):  
V. Hayes ◽  
Gerald Halpin
Keyword(s):  
Reaction Time ◽  
Repeated Measures ◽  
Rank Order ◽  
Reaction Times ◽  
Left Hand ◽  
Repeated Measures Analysis ◽  
The Mean ◽  
The Right ◽  
Mechanical Timer ◽  
Mean Reaction Time

Reaction times on each of the eight fingers were obtained for 24 skilled typists using an electric typewriter and a mechanical timer. Repeated-measures analysis of variance indicated significant differences among the mean reaction times of the eight fingers. Scheffé's multiple-comparison procedure indicated that the mean reaction time of each finger differed from that of every other finger and that the mean reaction time of the fingers on the left hand was significantly slower than the mean reaction time of fingers on the right hand. The average inter-class correlation coefficient among the fingers was .92 which indicated rank-order of reaction times to be similar across fingers.

Modeling Within-Person Variance in Reaction Time Data of Older Adults

GeroPsych ◽  
2011 ◽  
Vol 24 (4) ◽  
pp. 169-176 ◽  
Author(s):  
Philippe Rast ◽  
Daniel Zimprich
Keyword(s):  
Reaction Time ◽  
Cognitive Aging ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Reaction Time Data ◽  
Scale Model ◽  
Time Data ◽  
Time Task ◽  
The Mean ◽  
Second Wave

In order to model within-person (WP) variance in a reaction time task, we applied a mixed location scale model using 335 participants from the second wave of the Zurich Longitudinal Study on Cognitive Aging. The age of the respondents and the performance in another reaction time task were used to explain individual differences in the WP variance. To account for larger variances due to slower reaction times, we also used the average of the predicted individual reaction time (RT) as a predictor for the WP variability. Here, the WP variability was a function of the mean. At the same time, older participants were more variable and those with better performance in another RT task were more consistent in their responses.

Reaction Time and Time Course of Neuronal Responses in MT and MST at Different Stimulus Contrasts

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 157-157 ◽  
Author(s):  
A Thiele ◽  
K-P Hoffmann
Keyword(s):  
Reaction Time ◽  
Single Cell ◽  
Single Cells ◽  
Direction Selectivity ◽  
Contrast Level ◽  
Population Activity ◽  
Temporal Area ◽  
Population Mean ◽  
The Mean ◽  
Mean Reaction Time

Direction-selective neurons from the middle temporal area (MT) and the middle superior temporal area (MST) were recorded while a monkey performed a direction discrimination task. Stimuli consisted of evenly spaced bars moving in one of the four cardinal directions. Monkey's reaction time, single-cell latency, and direction selectivity were calculated when stimuli of 53%, 24%, and 4% contrast were presented, and the monkey indicated a correct decision. Mean reaction time was 359±77 ms at 53% contrast, 391±107 ms at 24% contrast, and 582±374 ms at 4% contrast. Most neurons exhibiting direction selective responses at 53% contrast was also active at 24% contrast (MT, 99%; MST, 88%). The number of neurons still exhibiting stimulus-related activity at 4% contrast dramatically decreased (MT to 28%; MST to 41%). Shortest latencies were found at high contrast level (53% contrast; MT, 29 ms; population mean, 76±40 ms; MST, 35 ms; population mean, 77±27 ms). Single cell and population latency increased at lower contrast (4% contrast: MT minimum, 86 ms; population mean, 180±76 ms; MST minimum, 97 ms; population mean, 205±56 ms). This indicates that the mean increase in latency at the single-cell level only partially reflects the increase in reaction time (mean reaction time increased by 223 ms, while mean single-cell latency increased by ∼100 ms in MT and MST). We therefore calculated the normalised population response at different contrast levels. The maximal population activity was always found at the highest contrast level and this was set to 1. In MT it took 75 – 80 ms from stimulus onset until half maximal activity (0.5) was reached at 53% contrast. To reach 0.5 took 85 – 90 ms at 24% contrast and 205 – 210 ms at 4% contrast. For MST the respective values were 85 ms (53% contrast), 90 ms (24% contrast) and 255 ms (4%) contrast. Thus the time to reach half the maximal population activity much better reflects the reaction time than the mean of the latencies calculated from single cells.

Emphasizing Nonword Decisions in Word-Decision Performance

2008 ◽  
Vol 103 (1) ◽  
pp. 97-101
Author(s):  
C. Darren Piercey
Keyword(s):  
Reaction Time ◽  
Lexical Decision ◽  
Reaction Times ◽  
Instruction Condition ◽  
Decision Performance ◽  
The Difference ◽  
Speed And Accuracy ◽  
Mean Reaction Time

A robust finding in the lexical decision literature is that decisions to words are made more quickly and accurately than decisions to nonwords. When instructions are presented to participants prior to an experiment, an emphasis is usually placed on identifying words. This study assessed whether instructing participants to emphasize nonword decisions would affect the performance of the speed and accuracy of identification. A total of 98 individuals took part, 49 in a Word Instruction condition and 49 in a Nonword Instruction condition. Analysis indicated changes in emphasis on words versus nonwords decreased the difference in mean reaction time between word and nonword decisions. An interesting finding is that the manipulation of instructions affected reaction times to words but not to nonwords. The analysis of accuracy yielded no significant comparisons. Further research is required to assess the importance of the finding that the manipulation of instructions affects only word decisions.

scholarly journals Oral Associative Reactions of Russians and Germans to Names of Mental States: Comparative and Quantitative Analysis

2020 ◽  
Vol 2020 (3) ◽  
pp. 46-57
Author(s):  
Ekaterina M. Alekseeva
Keyword(s):  
Quantitative Analysis ◽  
Reaction Time ◽  
Mental States ◽  
Cross Cultural ◽  
Experimental Procedure ◽  
Cross Cultural Study ◽  
Quantitative Content ◽  
The Mean ◽  
Speech Response ◽  
Mean Reaction Time

The article describes a cross-cultural study of associative oral representation of mental states. 32 Russian and 33German students – 53 female and 12 male aged from 20 up to 24 years participated in the research. The experimental procedure was developed on the basis of the DMDX program allowed to measure the time of speech response to the shown stimuli – names of 25 mental states. In the conditions of time deficiency probands had to call free and estimated associations (adjectives). The mean reaction time was calculated, quantitative content of associative fields was analyzed. In the Russian group associations (both free and estimated in the form of an adjective) to names of mental states were more quickly named. The average time of free oral associative reaction in the Russian group was 2114.6 ms, in the German - 2163.6 ms. The estimated associative response proved slower than the free associative response in both groups: the average time of the estimated oral associative reaction in the Russian group was 2246.9 ms, in the German – 2384.6 ms. During the experiment more evaluation associations in the form of adjectives were named than free ones. The vast majority of free associations to names of mental states were nouns. Most of the associations to names of mental states are unique.

scholarly journals Decreased ability to acquire food of a captive deaf dolphin (Tursiops truncatus): Slower reaction times and lower success rates

SURG Journal ◽  
2011 ◽  
Vol 4 (2) ◽  
pp. 63-70
Author(s):  
Katherine A. Wright
Keyword(s):  
Hearing Loss ◽  
Reaction Time ◽  
Success Rate ◽  
Tursiops Truncatus ◽  
Reaction Times ◽  
Anthropogenic Noise ◽  
Success Rates ◽  
Noise Levels ◽  
Atlantic Bottlenose Dolphin ◽  
Mean Reaction Time

Oceanic anthropogenic noise, such as naval sonar, can cause temporary hearing loss in cetaceans, but it is not known to what extent hearing loss affects cetacean behaviours such as feeding. This study used a captive deaf Atlantic bottlenose dolphin (Tursiops truncatus) to test the hypothesis that hearing loss would decrease a dolphin’s ability to acquire food by preventing echolocation (using echoes to locate fish). Reaction time (time to acquire dropped fish) and success rate (percentage of successfully acquired fish) were measured for the deaf dolphin and for two dolphins with no known hearing disabilities at Dolphins Plus in Florida in May 2009. The deaf dolphin had a significantly slower mean reaction time and a significantly lower mean success rate than those of the two other dolphins. A hydrophone suggested that the deaf dolphin could not echolocate, and thus relied mainly on vision. The results illustrate that hearing loss can negatively affect a dolphin’s ability to acquire food. Therefore, sources and effects of dolphin hearing loss require further investigation in order to provide targets for anthropogenic noise levels.

Temporal Characteristics of Interstimulus Interval in Serial Choice Reaction Time,

1973 ◽  
Vol 37 (3) ◽  
pp. 723-726
Author(s):  
Robert P. Fishburne ◽  
Wayne L. Waag
Keyword(s):  
Reaction Time ◽  
Choice Reaction Time ◽  
Interstimulus Interval ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Choice Reaction Time Task ◽  
Interval Duration ◽  
Random Interval ◽  
Temporal Characteristics ◽  
The Mean

The present study investigated the effects of presentation schedule and interstimulus interval duration in a serial choice reaction-time task. 45 Ss were randomly assigned to fixed, patterned, and random schedules having durations of interstimulus intervals of 2, 3, and 4 sec. As the regularity of the presentation schedule decreased, reaction time increased. For fixed-interval presentation, reaction time increased as a function of duration while the quickest reaction times occurred at the mean interstimulus interval for random-interval presentation. Reaction times remained the same under the patterned-interval presentation schedule.

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