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Sample records for reaction time preparacao

  1. Reaction Time (Polish language)

    OpenAIRE

    Iermakov, Sergii

    2014-01-01

    Reaction time is the interval time between the presentation of a stimulus and the initiation of the muscular response to that stimulus.If there is only one possible response (simple reaction time) it will only take a short time to react. If there are several possible responses (choice reaction time) then it will take longer to determine which response to carry out.

  2. Mesopic visual efficiency II: Reaction time experiments

    NARCIS (Netherlands)

    Walkey, H.; Orrevetelainen, P.; Barbur, J.; Halonen, L.; Goodman, T.; Alferdinck, J.W.A.M.; Freiding, A.; Szalmas, A.

    2007-01-01

    Reaction times are recorded to chromatic, mesopic stimuli to investigate mesopic reaction time spectral sensitivity. Measurements are made using three laboratory setups and a driving simulator. The chromatic stimuli have spectral distributions that range from quasi-monochromatic to broadband.

  3. Synthesis by the Pechini method and reaction combustion for the preparation of TiO{sub 2}: a comparative analysis; Sintese pelo metodo Pechini e reacao de combustao para preparacao de TiO{sub 2}: uma analise comparativa

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, E.P.; Ribeiro, P.C.; Freitas, N.L.; Lira, H.L.; Costa, A.C.F.M. da [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2009-07-01

    The aim of this work is to prepare TiO{sub 2} powder by Pechini and combustion reaction methods. A comparative analysis between the structural and morphological results obtained by the two methods was investigated. The powders were characterized by X-ray diffractions (XRD), infrared analysis, nitrogen adsorption (BET) and particle size distribution. The results from XRD show that the powders prepared by Pechini method and by combustion reaction using aniline as fuel, present anatase as major phase and traces of rutile phase. The values of crystallite size and surface area from BET were: 30 e 44 nm; 6.2 e 4.4 m{sup 2}/g, for the powders prepared by Pechini and combustion reaction, respectively. The values of particle size were: 21.9 e 5.3 {mu}m, for the powders prepared by Pechini and combustion reaction, respectively. The Pechini method was more suitable to obtain powders with irregular agglomerates, in the block shape with particles bonded softly and small crystallite size. (author)

  4. Reaction Time and Anticipation Time: Effects of Development.

    Science.gov (United States)

    Thomas, Jerry R.; And Others

    1981-01-01

    Results of a study indicated that, as age increased from seven to 20 years, reaction time decreased, with males having a more rapid reaction time than females. Beginning at age 10 or 11, subjects developed better motor plans and relied less on rapid reaction time to achieve good anticipation time. (FG)

  5. Attention and Reaction Time in Shotokan Athletes

    OpenAIRE

    António VencesBrito; Carlos Silva; Luis Cid; Dora Ferreira; Ana Marques

    2012-01-01

    The aim of this study is to analyze the attention capacity and the reaction time in Portuguese karate Shotokan athletes. Participated 96 Shotokan athletes from the Portuguese Karate Association. We physically characterized the sample (weight, height, body mass index, and body fat mass percentage) and evaluated Simple Reaction Time (TRS), Choice Reaction Time (TRE), Decision Time (TD) and the Distributed Attention (AD). Data was analyzed according to athletes’ group age (15 to 19 yr, 20 to 35 ...

  6. Normobaric hypoxia overnight impairs cognitive reaction time.

    Science.gov (United States)

    Pramsohler, Stephan; Wimmer, Stefan; Kopp, Martin; Gatterer, Hannes; Faulhaber, Martin; Burtscher, Martin; Netzer, Nikolaus Cristoph

    2017-05-15

    Impaired reaction time in patients suffering from hypoxia during sleep, caused by sleep breathing disorders, is a well-described phenomenon. High altitude sleep is known to induce periodic breathing with central apneas and oxygen desaturations, even in perfectly healthy subjects. However, deficits in reaction time in mountaineers or workers after just some nights of hypoxia exposure are not sufficiently explored. Therefore, we aimed to investigate the impact of sleep in a normobaric hypoxic environment on reaction time divided by its cognitive and motoric components. Eleven healthy non acclimatized students (5f, 6m, 21 ± 2.1 years) slept one night at a simulated altitude of 3500 m in a normobaric hypoxic room, followed by a night with polysomnography at simulated 5500 m. Preexisting sleep disorders were excluded via BERLIN questionnaire. All subjects performed a choice reaction test (SCHUHFRIED RT, S3) at 450 m and directly after the nights at simulated 3500 and 5500 m. We found a significant increase of cognitive reaction time with higher altitude (p = 0.026). No changes were detected in movement time (p = n.s.). Reaction time, the combined parameter of cognitive- and motoric reaction time, didn't change either (p = n.s.). Lower SpO2 surprisingly correlated significantly with shorter cognitive reaction time (r = 0.78, p = 0.004). Sleep stage distribution and arousals at 5500 m didn't correlate with reaction time, cognitive reaction time or movement time. Sleep in hypoxia does not seem to affect reaction time to simple tasks. The component of cognitive reaction time is increasingly delayed whereas motoric reaction time seems not to be affected. Low SpO2 and arousals are not related to increased cognitive reaction time therefore the causality remains unclear. The fact of increased cognitive reaction time after sleep in hypoxia, considering high altitude workers and mountaineering operations with overnight stays, should be further investigated.

  7. Effect of Mobile Use on Reaction Time

    OpenAIRE

    Chinmay Shah; P. A. Gokhale; H B Mehta

    2010-01-01

    The use of cellular phones has skyrocketed in recent years, with more than 118 million subscribers in the United States as of July 1, 2001. Recent estimates suggest that cell phone users spend 60% of their cell phone time while driving. Reaction time is one of the important methods used to study a person's central information processing speed and fast coordinated peripheral movement response. The purpose of this study was to compare the reaction time without mobile use and with mobile use. It...

  8. Reaction Time for Trimolecular Reactions in Compartment-based Reaction-Diffusion Models

    OpenAIRE

    Li, F; Chen, M; Erban, R; Cao, Y

    2016-01-01

    Trimolecular reaction models are investigated in the compartment-based (lattice-based) framework for stochastic reaction-diffusion modelling. The formulae for the first collision time and the mean reaction time are derived for the case where three molecules are present in the solution.

  9. AUDITORY REACTION TIME IN BASKETBALL PLAYERS AND HEALTHY CONTROLS

    OpenAIRE

    Ghuntla Tejas P.; Mehta Hemant B.; Gokhale Pradnya A.; Shah Chinmay J.

    2013-01-01

    Reaction is purposeful voluntary response to different stimuli as visual or auditory stimuli. Auditory reaction time is time required to response to auditory stimuli. Quickness of response is very important in games like basketball. This study was conducted to compare auditory reaction time of basketball players and healthy controls. The auditory reaction time was measured by the reaction time instrument in healthy controls and basketball players. Simple reaction time and choice reaction time...

  10. Autonomous Vehicles: Disengagements, Accidents and Reaction Times.

    Science.gov (United States)

    Dixit, Vinayak V; Chand, Sai; Nair, Divya J

    2016-01-01

    Autonomous vehicles are being viewed with scepticism in their ability to improve safety and the driving experience. A critical issue with automated driving at this stage of its development is that it is not yet reliable and safe. When automated driving fails, or is limited, the autonomous mode disengages and the drivers are expected to resume manual driving. For this transition to occur safely, it is imperative that drivers react in an appropriate and timely manner. Recent data released from the California trials provide compelling insights into the current factors influencing disengagements of autonomous mode. Here we show that the number of accidents observed has a significantly high correlation with the autonomous miles travelled. The reaction times to take control of the vehicle in the event of a disengagement was found to have a stable distribution across different companies at 0.83 seconds on average. However, there were differences observed in reaction times based on the type of disengagements, type of roadway and autonomous miles travelled. Lack of trust caused by the exposure to automated disengagements was found to increase the likelihood to take control of the vehicle manually. Further, with increased vehicle miles travelled the reaction times were found to increase, which suggests an increased level of trust with more vehicle miles travelled. We believe that this research would provide insurers, planners, traffic management officials and engineers fundamental insights into trust and reaction times that would help them design and engineer their systems.

  11. Autonomous Vehicles: Disengagements, Accidents and Reaction Times.

    Directory of Open Access Journals (Sweden)

    Vinayak V Dixit

    Full Text Available Autonomous vehicles are being viewed with scepticism in their ability to improve safety and the driving experience. A critical issue with automated driving at this stage of its development is that it is not yet reliable and safe. When automated driving fails, or is limited, the autonomous mode disengages and the drivers are expected to resume manual driving. For this transition to occur safely, it is imperative that drivers react in an appropriate and timely manner. Recent data released from the California trials provide compelling insights into the current factors influencing disengagements of autonomous mode. Here we show that the number of accidents observed has a significantly high correlation with the autonomous miles travelled. The reaction times to take control of the vehicle in the event of a disengagement was found to have a stable distribution across different companies at 0.83 seconds on average. However, there were differences observed in reaction times based on the type of disengagements, type of roadway and autonomous miles travelled. Lack of trust caused by the exposure to automated disengagements was found to increase the likelihood to take control of the vehicle manually. Further, with increased vehicle miles travelled the reaction times were found to increase, which suggests an increased level of trust with more vehicle miles travelled. We believe that this research would provide insurers, planners, traffic management officials and engineers fundamental insights into trust and reaction times that would help them design and engineer their systems.

  12. Attention and Reaction Time in Shotokan Athletes

    Directory of Open Access Journals (Sweden)

    António VencesBrito

    2012-07-01

    Full Text Available The aim of this study is to analyze the attention capacity and the reaction time in Portuguese karate Shotokan athletes. Participated 96 Shotokan athletes from the Portuguese Karate Association. We physically characterized the sample (weight, height, body mass index, and body fat mass percentage and evaluated Simple Reaction Time (TRS, Choice Reaction Time (TRE, Decision Time (TD and the Distributed Attention (AD. Data was analyzed according to athletes’ group age (15 to 19 yr, 20 to 35 yr and more than 35 yr, level of graduation (9th to 4th kyu, 3rd to 1st kyu, DAN and by gender (male and female. Male athletes present significant differences from female athletes in height, weight, years of practice and body fat mass. In relation to TRS all groups tend to a value near to 300 ms without significant differences among them, but the TRE and the TD are significantly higher in the Dan athletes and in the +35 yrs athletes than in the other groups. On the other hand the Dan and +35 yrs athletes tend to do less mistakes. Gender does not influence significantly the reaction time in the Shotokan karate athletes, but it seems that women tend to have smaller reaction times than men. Athletes with more years of practice and more graduation need more time to reply to the stimulus than the other athletes, but they tend to do fewer mistakes on their choices than other subjects. As for distributed attention, no significant differences were found in function of the athlete graduation, nor in function of gender. However, for distributed attention, we found statistical significant differences in function of the age, with the oldest athletes presenting lower levels of distributed attention. Our results seem to show that is necessary to do some modifications in the training process of Portuguese Shotokan karate athletes.

  13. Real-Time Polymerase Chain Reaction

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 4. Real-Time Polymerase Chain Reaction - A Revolution in ... Author Affiliations. Simarjot Singh Pabla1 Sarabjot Singh Pabla1. GH Patel Post Graduate Department of Computer Science and Technology Sardar Patel University Gujarat.

  14. No Evidence of Reaction Time Slowing in Autism Spectrum Disorder

    Science.gov (United States)

    Ferraro, F. Richard

    2016-01-01

    A total of 32 studies comprising 238 simple reaction time and choice reaction time conditions were examined in individuals with autism spectrum disorder (n?=?964) and controls (n?=?1032). A Brinley plot/multiple regression analysis was performed on mean reaction times, regressing autism spectrum disorder performance onto the control performance as…

  15. Exploring Listeners' Real-Time Reactions to Regional Accents

    Science.gov (United States)

    Watson, Kevin; Clark, Lynn

    2015-01-01

    Evaluative reactions to language stimuli are presumably dynamic events, constantly changing through time as the signal unfolds, yet the tools we usually use to capture these reactions provide us with only a snapshot of this process by recording reactions at a single point in time. This paper outlines and evaluates a new methodology which employs…

  16. Effect of Reaction Developing Training on Audio-Visual Feet Reaction Time in Wrestlers

    Science.gov (United States)

    Kaya, Mustafa

    2016-01-01

    Reaction time is one of the most determinative elements for a successful sports performance. The purpose of this study was to investigate the effect of 12-week feet reaction developing trainings upon feet reaction time of females at 11-13 age interval. Volunteer sportsmen between 11 and 13 age interval who were active in Tokat Provincial…

  17. Extreme reaction times determine fluctuation scaling in human color vision

    Science.gov (United States)

    Medina, José M.; Díaz, José A.

    2016-11-01

    In modern mental chronometry, human reaction time defines the time elapsed from stimulus presentation until a response occurs and represents a reference paradigm for investigating stochastic latency mechanisms in color vision. Here we examine the statistical properties of extreme reaction times and whether they support fluctuation scaling in the skewness-kurtosis plane. Reaction times were measured for visual stimuli across the cardinal directions of the color space. For all subjects, the results show that very large reaction times deviate from the right tail of reaction time distributions suggesting the existence of dragon-kings events. The results also indicate that extreme reaction times are correlated and shape fluctuation scaling over a wide range of stimulus conditions. The scaling exponent was higher for achromatic than isoluminant stimuli, suggesting distinct generative mechanisms. Our findings open a new perspective for studying failure modes in sensory-motor communications and in complex networks.

  18. A study of systolic time intervals in lepra reaction.

    Science.gov (United States)

    Zawar, P B; Chawhan, R N; Mahajani, V V

    1983-10-01

    Systolic time intervals (STI) were measured in 20 control subjects and 20 cases of lepromatous leprosy in lepra reaction. Significant differences in the pre-ejection period (PEP), PEP/LVET and isovolumic contraction (IVCT) were observed between the groups. The abnormalities of STI observed in patients of lepra reaction are characteristic of left ventricular dysfunction in patients of lepra reaction.

  19. Reaction Time as a Predictor of PPVT Performance in Preschoolers.

    Science.gov (United States)

    Telzrow, Cathy F.; Hartlage, Lawrence C.

    The relationships between reaction time (RT), movement time (MT), visual hemi-space preferences in RT and MT, and the Peabody Picture Vocabulary Test (PPVT) were investigated in order to evaluate reaction time as a measurement practice with very young children. The sample was composed of 49 white, middle-class children ranging in age from 24 to 77…

  20. Reaction Time of a Group of Physics Students

    CERN Document Server

    Saxena, Charu; Arun, P

    2007-01-01

    The reaction time of a group of students majoring in Physics is reported here. Strong co-relation between fatigue, reaction time and performance have been seen and may be useful for academicians and administrators responsible of working out time-tables, course structures, students counsellings etc.

  1. Reading and a diffusion model analysis of reaction time.

    Science.gov (United States)

    Naples, Adam; Katz, Leonard; Grigorenko, Elena L

    2012-01-01

    Processing speed is associated with reading performance. However, the literature is not clear either on the definition of processing speed or on why and how it contributes to reading performance. In this study we demonstrated that processing speed, as measured by reaction time, is not a unitary construct. Using the diffusion model of two-choice reaction time, we assessed processing speed in a series of same-different reaction time tasks for letter and number strings. We demonstrated that the association between reaction time and reading performance is driven by processing speed for reading-related information, but not motor or sensory encoding speed.

  2. Are accuracy and reaction time affected via different processes?

    NARCIS (Netherlands)

    Mulder, M.J.; van Maanen, L.

    2013-01-01

    A recent study by van Ede et al. (2012) shows that the accuracy and reaction time in humans of tactile perceptual decisions are affected by an attentional cue via distinct cognitive and neural processes. These results are controversial as they undermine the notion that accuracy and reaction time are

  3. Reaction Time of a Group of Physics Students

    Science.gov (United States)

    Saxena, Charu; Kaur, Rini; Arun, P.

    2008-01-01

    The reaction time of a group of students majoring in physics is reported here. Strong correlation between fatigue, reaction time and performance has been observed and may be useful for academicians and administrators responsible for working out timetables, course structures, student counsellings, etc. (Contains 5 figures, 1 table, and 1 footnote.)

  4. [Reaction time of drivers who caused road traffic accidents].

    Science.gov (United States)

    Durić, Predrag; Filipović, Danka

    2009-01-01

    Human factor is the single cause of road traffic injuries in 57%, and together with other factors in more than 90% of all road traffic accidents. Human factor includes many aspects, where reaction time is very important. Thirty healthy drivers 28-40 y.o. with 50-500 km passed per week, having caused at least one road traffic accident in the last ten years were selected, provided they were not under the influence of alcohol and drugs during traffic accident. The same number of control were selected. Both cases and controls were tested to reaction time. We found statistically significant difference between car drivers who caused car accidents and those who did not in both simple and choice reaction times. Car drivers who caused road traffic accidents have longer reaction time (both simple and choice reaction time), but as the tasks were more complex, that difference was less visible. Since drivers involved in this study had introductory phase before measuring their reaction times, they faced with unpleasant sound when they made mistake, which forced them to be aware not to make a mistake in further tasks, so they showed longer reaction times. Measuring of reaction time seems to be important, and as we have showed they are different in drivers who have caused road traffic accidents and those who have do not.

  5. Predicting Fluid Intelligence by Components of Reaction Time Distributions from Simple Choice Reaction Time Tasks

    Directory of Open Access Journals (Sweden)

    Yoanna Schulz-Zhecheva

    2016-07-01

    Full Text Available Mean reaction times (RT and the intra-subject variability of RT in simple RT tasks have been shown to predict higher-order cognitive abilities measured with psychometric intelligence tests. To further explore this relationship and to examine its generalizability to a sub-adult-aged sample, we administered different choice RT tasks and Cattell’s Culture Fair Intelligence Test (CFT 20-R to n = 362 participants aged eight to 18 years. The parameters derived from applying Ratcliff’s diffusion model and an ex-Gaussian model to age-residualized RT data were used to predict fluid intelligence using structural equation models. The drift rate parameter of the diffusion model, as well as σ of the ex-Gaussian model, showed substantial predictive validity regarding fluid intelligence. Our findings demonstrate that stability of performance, more than its mere speed, is relevant for fluid intelligence and we challenge the universality of the worst performance rule observed in adult samples.

  6. A complex reaction time study (Sternberg) in space flight

    Science.gov (United States)

    Thornton, W.; Uri, John; Moore, Tom

    1993-01-01

    Simple and complex (Sternberg) reaction time studies were flown on three and seven day Shuttle flights in 1985. Three subjects did selftesting with an onboard handheld calculator without difficulty. There was little change in simple reaction time. One subject demonstrated a decrease in the processing rate during space motion sickness while a second exhibited an increase in complex reaction time without a change in processing rate during a period of high work load. The population was too small to demonstrate significant changes. This study demonstrates the ease and practicality of such measurements and indicates the potential value of such studies in space.

  7. Evolution of Complex Maillard Chemical Reactions, Resolved in Time.

    Science.gov (United States)

    Hemmler, Daniel; Roullier-Gall, Chloé; Marshall, James W; Rychlik, Michael; Taylor, Andrew J; Schmitt-Kopplin, Philippe

    2017-06-12

    In this study, we monitored the thermal formation of early ribose-glycine Maillard reaction products over time by ion cyclotron resonance mass spectrometry. Here, we considered sugar decomposition (caramelization) apart from compounds that could only be produced in the presence of the amino acid. More than 300 intermediates as a result of the two initial reactants were found after ten hours (100 °C) to participate in the interplay of the Maillard reaction cascade. Despite the large numerical variety the majority of intermediates follow simple and repetitive reaction patterns. Dehydration, carbonyl cleavage, and redox reactions turned out to have a large impact on the diversity the Maillard reaction causes. Although the Amadori breakdown is considered as the main Maillard reaction pathway, other reactive intermediates, often of higher molecular weight than the Amadori rearrangement product, contribute to a large extent to the multitude of intermediates we observed.

  8. Comparison of Sprint Reaction and Visual Reaction Times of Athletes in Different Branches

    Science.gov (United States)

    Akyüz, Murat; Uzaldi, Basar Basri; Akyüz, Öznur; Dogru, Yeliz

    2017-01-01

    The aims of this study are to analyse sprint reaction and visual reaction times of female athletes of different branches competing in Professional leagues and to show the differences between them. 42 voluntary female athletes from various branches of Professional leagues of Istanbul (volleyball, basketball, handball) were included in the…

  9. Genetic analysis of reaction time variability : room for improvement?

    NARCIS (Netherlands)

    Kuntsi, J.; Frazier-Wood, A. C.; Banaschewski, T.; Gill, M.; Miranda, A.; Oades, R. D.; Roeyers, H.; Rothenberger, A.; Steinhausen, H. -C.; van der Meere, J. J.; Faraone, S. V.; Asherson, P.; Rijsdijk, F.

    Background. Increased reaction time variability (RTV) on cognitive tasks requiring a speeded response is characteristic of several psychiatric disorders. In attention deficit hyperactivity disorder (ADHD), the association with RTV is strong phenotypically and genetically, yet high RTV is not a

  10. Improved perception-reaction time information for intersection sight distance

    Science.gov (United States)

    2002-08-01

    Perception-reaction time (PRT) data were obtained in an operational setting to assess the adequacy of existing PRT specifications for intersection sight distance standards. A sample of 124 subjects traversed a 3-hour driving circuit in an instrumente...

  11. Overlap of movement planning and movement execution reduces reaction time.

    Science.gov (United States)

    Orban de Xivry, Jean-Jacques; Legrain, Valéry; Lefèvre, Philippe

    2017-01-01

    Motor planning is the process of preparing the appropriate motor commands in order to achieve a goal. This process has largely been thought to occur before movement onset and traditionally has been associated with reaction time. However, in a virtual line bisection task we observed an overlap between movement planning and execution. In this task performed with a robotic manipulandum, we observed that participants (n = 30) made straight movements when the line was in front of them (near target) but often made curved movements when the same target was moved sideways (far target, which had the same orientation) in such a way that they crossed the line perpendicular to its orientation. Unexpectedly, movements to the far targets had shorter reaction times than movements to the near targets (mean difference: 32 ms, SE: 5 ms, max: 104 ms). In addition, the curvature of the movement modulated reaction time. A larger increase in movement curvature from the near to the far target was associated with a larger reduction in reaction time. These highly curved movements started with a transport phase during which accuracy demands were not taken into account. We conclude that an accuracy demand imposes a reaction time penalty if processed before movement onset. This penalty is reduced if the start of the movement consists of a transport phase and if the movement plan can be refined with respect to accuracy demands later in the movement, hence demonstrating an overlap between movement planning and execution. In the planning of a movement, the brain has the opportunity to delay the incorporation of accuracy requirements of the motor plan in order to reduce the reaction time by up to 100 ms (average: 32 ms). Such shortening of reaction time is observed here when the first phase of the movement consists of a transport phase. This forces us to reconsider the hypothesis that motor plans are fully defined before movement onset. Copyright © 2017 the American Physiological Society.

  12. EFFECT OF GENDER DIFFERENCE ON BRAKE REACTION TIME

    Directory of Open Access Journals (Sweden)

    Ashok

    2016-02-01

    Full Text Available BACKGROUND OF THE STUDY Reaction time is the time taken to respond to a stimulus or change in the environment. It is a method to assess the time taken from the perception of a stimulus followed by mental processing for a motor response. Reaction time in various day to day activities as in driving a car is very important. Brake reaction time (BRT is the time taken for the driver to respond to visualize an object and to press the brake pedal. It is affected by many features like age, gender, neuromuscular disorders. OBJECTIVE OF THE STUDY Study has been undertaken to compare the BRT in male and female drivers and to analyze the effect of sex difference on Brake reaction time. MATERIALS & METHODS Male and female subjects between the age group of 25 – 35 years with driving license were included. Study is conducted in a stationary car. An in-house built; braking timer is fixed to the electric circuit of the braking system in the car. This device is wirelessly connected to the reaction time software installed in the laptop. The subject is instructed to press the brake pedal when the light changed from red to green in the laptop screen. 5 readings are taken and the mean BRT is recorded. STATISTICAL ANALYSIS & RESULTS Statistical analysis done with unpaired student t test indicates that the BRT was more in the females than the males and was statistically significant (p value - 0007. CONCLUSION Gender difference has a significant effect on BRT and reaction time in female is longer than for the males.

  13. Evolution of Complex Maillard Chemical Reactions, Resolved in Time

    OpenAIRE

    Hemmler, Daniel; Roullier-Gall, Chlo?; Marshall, James W.; Rychlik, Michael; Taylor, Andrew J.; Schmitt-Kopplin, Philippe

    2017-01-01

    In this study, we monitored the thermal formation of early ribose-glycine Maillard reaction products over time by ion cyclotron resonance mass spectrometry. Here, we considered sugar decomposition (caramelization) apart from compounds that could only be produced in the presence of the amino acid. More than 300 intermediates as a result of the two initial reactants were found after ten hours (100??C) to participate in the interplay of the Maillard reaction cascade. Despite the large numerical ...

  14. The Effect of Road Traffic Noise on Reaction Time.

    Science.gov (United States)

    Alimohammadi, Iraj; Zokaei, Mojtaba; Sandrock, Stephan

    2015-01-01

    Traffic noise is one of the main important sources in urban noise pollution, which causes various physiological and psychological effects that can cause disturbs in performance, sleep disturbances, hearing loss and impact on job performance. This study was conducted to verify the impact of road traffic noise on reaction time in terms of extraversion and sex. Traffic noise was measured and recorded in 10 arterial streets in Tehran, and then the recorded noise was emitted towards participants in an acoustic room. The participants were 80 (40 cases and 40 controls) students. Personality type was determined by Eysenck Personality Inventory (EPI) questioner. Reaction time before and after exposure to traffic noise was measured. Reaction time before exposure to traffic noise did not differ (P=0.437) significantly between introverts and extraverts. However, it was increased significantly in both groups after exposure to traffic noise (PTraffic noise augmented reaction time of both males and females. This study also revealed that exposure to traffic noise leads to increase in reaction time.

  15. Effects of partial sleep deprivation on reaction time in anesthesiologists.

    Science.gov (United States)

    Saadat, Haleh; Bissonnette, Bruno; Tumin, Dmitry; Raman, Vidya; Rice, Julie; Barry, N'Diris; Tobias, Joseph

    2017-04-01

    Fatigue in anesthesiologists may have implications that extend beyond individual well-being. The aim of the present study was to evaluate the impact of sleep deprivation on the reaction time in anesthesiologists either after an overnight call or regular working hours. Moderation of this effect by coping strategies was observed. Psychomotor vigilance test was used to assess reaction time in 23 anesthesiologists at two time-points: (i) on a regular non-call day and (ii) after a 17-h in-house call. Student's paired t-test was used to compare Psychomotor Vigilance Task data at these two moments. Change score regression was performed to determine the association between coping strategies, assessed using the Coping Strategy Indicator instrument, and decline in reaction time after night call. Twenty-one colleagues completed the psychomotor vigilance test measurements after two decided to end their participation for personal reasons. Post-call psychomotor vigilance test mean reaction time decreased by an average of 31.2 ms (95% CI: 0.5, 61.9; P = 0.047) when compared to regular day. Reliance on specific coping mechanisms, indicated by Coping Strategy Indicator scale scores, included problem-solving (28 ± 4), followed by seeking social support (23 ± 5) and avoidance (19 ± 4). The change score regression model (r2 = 0.48) found that greater reliance on avoidance was associated with greater increase in reaction time after night call. Reaction time increased considerably in anesthesiologists after a night call duty. Greater subjective reliance on avoidance as a coping strategy was associated with greater deterioration in performance. © 2016 John Wiley & Sons Ltd.

  16. Quantification of reaction time and time perception during Space Shuttle operations

    Science.gov (United States)

    Ratino, D. A.; Repperger, D. W.; Goodyear, C.; Potor, G.; Rodriguez, L. E.

    1988-01-01

    A microprocessor-based test battery containing simple reaction time, choice reaction time, and time perception tasks was flown aboard a 1985 Space Shuttle flight. Data were obtained from four crew members. Individual subject means indicate a correlation between change in reaction time during the flight and the presence of space motion sickness symptoms. The time perception task results indicate that the shortest duration task time (2 s) is progressively overestimated as the mission proceeds and is statistically significant when comparing preflight and postflight baselines. The tasks that required longer periods of time to estimate (8, 12, and 16 s) are less affected.

  17. Conditioning reaction time: evidence for a process of conditioned automatization.

    Science.gov (United States)

    Montare, A

    1992-12-01

    The classical conditioning of the standard, simple reaction time (RT) in 140 college men and women is described. Consequent to an anticipatory instructed conditioning procedure, two experimental and two control groups acquired voluntary, controlled US(light)-URTR (unconditioned reaction-time response) associations which then served as the foundation for subsequent classical conditioning when a novel CS (auditory click) was simultaneously paired with the US. Conditioned reaction-time responses (CRTRs) occurred significantly more often during test trials in the two experimental groups than in the two control groups. Statistical and introspective findings support the notion that observed CRTRs may be products of cognitively unconscious conditioned automatization whereby the conditioning of relatively slow, voluntary, and controlled US-URTR associations leads to the acquisition of relatively fast, involuntary, and automatic CS-CRTR associations.

  18. Reaction time in relation to duration of heroin abuse

    Directory of Open Access Journals (Sweden)

    Martinović-Mitrović Slađana

    2011-01-01

    Full Text Available Introduction. Consequences of heroin abuse include organic damage of cerebral structures. The level of impairments is in a direct and positive relation with the length of heroin abuse. Objective. The aim of this research was the evaluation of the reaction time with heroin addicts with different length of substance abuse. Methods. Research method: 90 examinees were divided into three groups with relation to the length of heroin abuse. Data collection included a questionnaire referring to socio-demographic and addictive characteristics. A specially designed programme was used for the evaluation of reaction time to audio/ visual signal. Results. In relation to the reaction time as overall model, the difference between examinees with different length of heroin abuse can be found on the marginal level of significance (F=1.69; df=12; p=0.07. In visual modality, with the increase of length of heroin abuse leads to a significant prolongation of simple (the first visual sign: F=3.29; df=2; p=0.04 and choice reaction time (the second visual sign: F=4.97; df=2; p=0.00; the third visual sign: F=3.08; df=2; p=0.05. Longer heroin consumption also leads to the prolongation of the simple (the first auditory task: F=3.41; df=2; p=0.04 and the complex auditory reaction time (the second auditory task: F=5.67; df=2; p=0.01; the third auditory task: F=6.42; df=2; p=0.00. Conclusion. Heroin abuse leads to the prolongation of both simple and choice reaction time in visual as well as auditory modality. The average daily dose of opiates was the most important predictor of the abovementioned cognitive dysfunction.

  19. Dwell time analysis of a single-molecule mechanochemical reaction.

    Science.gov (United States)

    Szoszkiewicz, Robert; Ainavarapu, Sri Rama Koti; Wiita, Arun P; Perez-Jimenez, Raul; Sanchez-Ruiz, Jose M; Fernandez, Julio M

    2008-02-19

    Force-clamp spectroscopy is a novel technique for studying mechanochemistry at the single-bond level. Single disulfide bond reduction events are accurately detected as stepwise increases in the length of polyproteins that contain disulfide bonds and that are stretched at a constant force with the cantilever of an atomic force microscope (AFM). The kinetics of this reaction has been measured from single-exponential fits to ensemble averages of the reduction events. However, exponential fits are notoriously ambiguous to use in cases of kinetic data showing multiple reaction pathways. Here we introduce a dwell time analysis technique, of widespread use in the single ion channel field, that we apply to the examination of the kinetics of reduction of disulfide bonds measured from single-molecule force-clamp spectroscopy traces. In this technique, exponentially distributed dwell time data is plotted as a histogram with a logarithmic time scale and a square root ordinate. The advantage of logarithmic histograms is that exponentially distributed dwell times appear as well-defined peaks in the distribution, greatly enhancing our ability to detect multiple kinetic pathways. We apply this technique to examine the distribution of dwell times of 4488 single disulfide bond reduction events measured in the presence of two very different kinds of reducing agents: tris-(2-carboxyethyl)phosphine hydrochloride (TCEP) and the enzyme thioredoxin (TRX). A different clamping force is used for each reducing agent to obtain distributions of dwell times on a similar time scale. In the case of TCEP, the logarithmic histogram of dwell times showed a single peak, corresponding to a single reaction mechanism. By contrast, similar experiments done with TRX showed two well-separated peaks, marking two distinct modes of chemical reduction operating simultaneously. These experiments demonstrate that dwell time analysis techniques are a powerful approach to studying chemical reactions at the single

  20. Is Reaction Time Variability in ADHD Mainly at Low Frequencies?

    Science.gov (United States)

    Karalunas, Sarah L.; Huang-Pollock, Cynthia L.; Nigg, Joel T.

    2013-01-01

    Background: Intraindividual variability in reaction times (RT variability) has garnered increasing interest as an indicator of cognitive and neurobiological dysfunction in children with attention deficit hyperactivity disorder (ADHD). Recent theory and research has emphasized specific low-frequency patterns of RT variability. However, whether…

  1. TaqMan Real-Time Polymerase Chain Reaction and ...

    African Journals Online (AJOL)

    TaqMan Real-Time Polymerase Chain Reaction and. Pyrosequencing using Single Nucleotide Polymorphism. Protocol for Rapid Determination of ALDH2 *2 in a Chinese. Population. Ju-yi Li1, Jin-hu Wu2, Yan Zhang2, Xiu-fang Wang2, Jie Jin2 and Yi Wang1*. 1Department of Pharmacy, The Central Hospital of Wuhan, ...

  2. Reaction + movement-time and sidedness in Shotokan karate students.

    Science.gov (United States)

    Layton, C

    1993-06-01

    Reaction + movement-times on four counter-offensive techniques of Shotokan karate were found not to differ with regard to sidedness, despite right-sided bias in such techniques in Shotokan kata (forms) previously recorded, and with no attempt to correct the bias in basics and/or sparring over a long period.

  3. Brain microstructural correlates of visuospatial choice reaction time in children

    DEFF Research Database (Denmark)

    Madsen, Kathrine Skak; Baaré, William F C; Skimminge, Arnold

    2011-01-01

    in the corticospinal tracts and neostriatum. In a cohort of 75 typically-developing children aged 7 to 13years, mean 5-choice reaction times (RTs) were assessed. We hypothesised that children with faster choice RTs would show lower mean diffusivity (MD) in the corticospinal tracts and neostriatum and higher fractional...

  4. Reaction schemes, escape times and geminate recombinations in particle-based spatial simulations of biochemical reactions.

    Science.gov (United States)

    Klann, Michael; Koeppl, Heinz

    2013-08-01

    Modeling the spatiotemporal dynamics of biochemical reaction systems at single-molecule resolution has become feasible with the increase of computing power and is applied especially to cellular signal transduction. For an association reaction the two molecules have to be in contact. Hence, a physically faithful model of the molecular interaction assumes non-overlapping molecules that interact at their surfaces (boundary scheme). For performance reasons, this model can be replaced by particles that can overlap and react when they are closer than a certain distance with a reaction probability (volume scheme). Here we present an analytical approximation for the reaction probability in the volume scheme and compare the volume- with the boundary scheme. A dissociation reaction, in contrast, creates two molecules next to each other. If the reaction is reversible, these two products can directly re-bind again, leading to an overestimation of the dimerized state in the simulation. We show how the correct recombination rate can be achieved if the products of the dissociation are placed at identical positions, but cannot react for a certain timespan. This refractory time corresponds to the completion of the diffusion-controlled dissociation of the two molecules to their contact distance r(i)+r(j) at t = τ ×(r(i)+r(j))²/(D(i)+D(j) with τ = 1/10 for molecules with radii r(i) and r(j) and diffusion coefficients D(i) and D(j), respectively.

  5. Reaction time on fencing and karate high level athletes

    OpenAIRE

    Martínez de Quel Pérez, Óscar; Saucedo Morales, Francisco; López Adán, Enrique; Sillero Quintana, Manuel

    2008-01-01

    The great speed of the actions in combat sports makes very difficult to react quickJy without mistakes. If the fighter had longer time to react, their reaction would be more accurate. This fact gives relevance to choice lime reaction (CRT) studies on these kinds of sports. The importance of the athletes1 physical or psychological abilities varies depending on the sporl played. According to the requirements of the speciality, players who reach Ihe maximum level will be those who have the chara...

  6. Visual evoked potentials, reaction times and eye dominance in cricketers.

    Science.gov (United States)

    Thomas, N G; Harden, L M; Rogers, G G

    2005-09-01

    Few studies have examined the physiology of cricket, including the difference in ability between batsmen to make controlled contact with a ball bowled at high speed. We therefore measured visual evoked potentials and choice reaction times with dominant eyes, non-dominant eyes, and both eyes together, in 15 elite batsmen and 10 elite bowlers (aged 20.9 SD 1.9 years) and 9 control subjects (aged 20.2 SD 1.5 years). The latency and amplitude of waves N70, P100 and N145 were determined for each visual evoked potential (VEP). In addition interpeak latencies and peak to peak amplitudes were measured. The subjects also completed a choice reaction test to a visual stimulus. We found that cricketers were not more likely to have crossed dominance (dominant eye contralateral to dominant hand) than controls. Cricketers had a faster latency for VEP wave N70 than controls (p=0.03). However reaction time was not different between cricketers and the control group. Across all subjects, in comparison to monocular testing, binocular testing led to a faster choice reaction time (p=0.02) and larger amplitudes of VEP wave N70 (p=0.01). Visual processing during the first 100(-1)50 ms of the balls flight together with binocular vision facilitates retinal activation in talented cricketers.

  7. The time course of corticospinal excitability during a simple reaction time task.

    Science.gov (United States)

    Kennefick, Michael; Maslovat, Dana; Carlsen, Anthony N

    2014-01-01

    The production of movement in a simple reaction time task can be separated into two time periods: the foreperiod, which is thought to include preparatory processes, and the reaction time interval, which includes initiation processes. To better understand these processes, transcranial magnetic stimulation has been used to probe corticospinal excitability at various time points during response preparation and initiation. Previous research has shown that excitability decreases prior to the "go" stimulus and increases following the "go"; however these two time frames have been examined independently. The purpose of this study was to measure changes in CE during both the foreperiod and reaction time interval in a single experiment, relative to a resting baseline level. Participants performed a button press movement in a simple reaction time task and excitability was measured during rest, the foreperiod, and the reaction time interval. Results indicated that during the foreperiod, excitability levels quickly increased from baseline with the presentation of the warning signal, followed by a period of stable excitability leading up to the "go" signal, and finally a rapid increase in excitability during the reaction time interval. This excitability time course is consistent with neural activation models that describe movement preparation and response initiation.

  8. The effect of ego depletion on sprint start reaction time.

    Science.gov (United States)

    Englert, Chris; Bertrams, Alex

    2014-10-01

    In the current study, we consider that optimal sprint start performance requires the self-control of responses. Therefore, start performance should depend on athletes' self-control strength. We assumed that momentary depletion of self-control strength (ego depletion) would either speed up or slow down the initiation of a sprint start, where an initiation that was sped up would carry the increased risk of a false start. Applying a mixed between- (depletion vs. nondepletion) and within- (before vs. after manipulation of depletion) subjects design, we tested the start reaction times of 37 sport students. We found that participants' start reaction times decelerated after finishing a depleting task, whereas it remained constant in the nondepletion condition. These results indicate that sprint start performance can be impaired by unrelated preceding actions that lower momentary self-control strength. We discuss practical implications in terms of optimizing sprint starts and related overall sprint performance.

  9. Effect of reaction time on the formation of disinfection byproducts

    Science.gov (United States)

    Rathbun, R.E.

    1997-01-01

    The effect of reaction time on the trihalomethane and nonpurgeable total organic-halide formation potentials was determined by chlorinating water samples from the Mississippi, Missouri, and Ohio Rivers. Samples were collected for three seasons at 12 locations on the Mississippi from Minneapolis, Minnesota, to New Orleans, Louisiana, and on the Missouri and Ohio 1.6 kilometers above their confluences with the Mississippi. Both types of compounds formed rapidly during the initial stages of the reaction-time period, with formation rates decreasing with time. The ratio of the nonpurgeable total organic-halide and trihalomethane concentrations decreased with time, with the nonpurgeable total organic-halide compounds forming faster during the first stages of the time period and the trihalomethane compounds forming faster during the latter stages of the time period. Variation with distance along the Mississippi River of the formation rates approximately paralleled the variation of the dissolved organic carbon concentration, indicating that the rates of formation, as well as the concentrations of the compounds formed, depended on the dissolved organic carbon concentration.

  10. Timing of Gun Fire Influences Sprinters’ Multiple Joint Reaction Times of Whole Body in Block Start

    OpenAIRE

    Mitsuo Otsuka; Toshiyuki Kurihara; Tadao Isaka

    2017-01-01

    Experienced sprinters are specifically adapted to pre-planning an advanced motor program. Herein, sprinters are able to immediately accelerate their center of mass forward with a whole-body coordinated motion, following a steady state crouched position. We examined the effect of variable timing of reaction signals on multiple joint reaction times (RT) and whole-body RT for specialist sprinters. Twenty well-experienced male sprinters performed five start-dashes from a block start under five va...

  11. Perceived smoking availability differentially affects mood and reaction time.

    Science.gov (United States)

    Ross, Kathryn C; Juliano, Laura M

    2015-06-01

    This between subjects study explored the relationship between smoking availability and smoking motivation and is the first study to include three smoking availability time points. This allowed for an examination of an extended period of smoking unavailability, and a test of the linearity of the relationships between smoking availability and smoking motivation measures. Ninety 3-hour abstinent smokers (mean ~15 cigarettes per day) were randomly assigned to one of three availability manipulations while being exposed to smoking stimuli (i.e., pack of cigarettes): smoke in 20 min, smoke in 3 h, or smoke in 24 h. Participants completed pre- and post-manipulation measures of urge, positive affect and negative affect, and simple reaction time. The belief that smoking would next be available in 24 h resulted in a significant decrease in positive affect and increase in negative affect relative to the 3 h and 20 min conditions. A Lack of Fit test suggested a linear relationship between smoking availability and affect. A quadratic model appeared to be a better fit for the relationship between smoking availability and simple reaction time with participants in the 24 h and 20 min conditions showing a greater slowing of reaction time relative to the 3 h condition. There were no effects of the manipulations on self-reported urge, but baseline ceiling effects were noted. Future investigations that manipulate three or more periods of time before smoking is available will help to better elucidate the nature of the relationship between smoking availability and smoking motivation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Microsecond time-scale kinetics of transient biochemical reactions.

    Directory of Open Access Journals (Sweden)

    Sandra Mitić

    Full Text Available To afford mechanistic studies in enzyme kinetics and protein folding in the microsecond time domain we have developed a continuous-flow microsecond time-scale mixing instrument with an unprecedented dead-time of 3.8 ± 0.3 μs. The instrument employs a micro-mixer with a mixing time of 2.7 μs integrated with a 30 mm long flow-cell of 109 μm optical path length constructed from two parallel sheets of silver foil; it produces ultraviolet-visible spectra that are linear in absorbance up to 3.5 with a spectral resolution of 0.4 nm. Each spectrum corresponds to a different reaction time determined by the distance from the mixer outlet, and by the fluid flow rate. The reaction progress is monitored in steps of 0.35 μs for a total duration of ~600 μs. As a proof of principle the instrument was used to study spontaneous protein refolding of pH-denatured cytochrome c. Three folding intermediates were determined: after a novel, extremely rapid initial phase with τ = 4.7 μs, presumably reflecting histidine re-binding to the iron, refolding proceeds with time constants of 83 μs and 345 μs to a coordinatively saturated low-spin iron form in quasi steady state. The time-resolution specifications of our spectrometer for the first time open up the general possibility for comparison of real data and molecular dynamics calculations of biomacromolecules on overlapping time scales.

  13. Equilibrium distributions of simple biochemical reaction systems for time-scale separation in stochastic reaction networks.

    Science.gov (United States)

    Mélykúti, Bence; Hespanha, João P; Khammash, Mustafa

    2014-08-06

    Many biochemical reaction networks are inherently multiscale in time and in the counts of participating molecular species. A standard technique to treat different time scales in the stochastic kinetics framework is averaging or quasi-steady-state analysis: it is assumed that the fast dynamics reaches its equilibrium (stationary) distribution on a time scale where the slowly varying molecular counts are unlikely to have changed. We derive analytic equilibrium distributions for various simple biochemical systems, such as enzymatic reactions and gene regulation models. These can be directly inserted into simulations of the slow time-scale dynamics. They also provide insight into the stimulus-response of these systems. An important model for which we derive the analytic equilibrium distribution is the binding of dimer transcription factors (TFs) that first have to form from monomers. This gene regulation mechanism is compared to the cases of the binding of simple monomer TFs to one gene or to multiple copies of a gene, and to the cases of the cooperative binding of two or multiple TFs to a gene. The results apply equally to ligands binding to enzyme molecules.

  14. Reaction times to weak test lights. [psychophysics biological model

    Science.gov (United States)

    Wandell, B. A.; Ahumada, P.; Welsh, D.

    1984-01-01

    Maloney and Wandell (1984) describe a model of the response of a single visual channel to weak test lights. The initial channel response is a linearly filtered version of the stimulus. The filter output is randomly sampled over time. Each time a sample occurs there is some probability increasing with the magnitude of the sampled response - that a discrete detection event is generated. Maloney and Wandell derive the statistics of the detection events. In this paper a test is conducted of the hypothesis that the reaction time responses to the presence of a weak test light are initiated at the first detection event. This makes it possible to extend the application of the model to lights that are slightly above threshold, but still within the linear operating range of the visual system. A parameter-free prediction of the model proposed by Maloney and Wandell for lights detected by this statistic is tested. The data are in agreement with the prediction.

  15. Critical time scales for advection-diffusion-reaction processes

    Science.gov (United States)

    Ellery, Adam J.; Simpson, Matthew J.; McCue, Scott W.; Baker, Ruth E.

    2012-04-01

    The concept of local accumulation time (LAT) was introduced by Berezhkovskii and co-workers to give a finite measure of the time required for the transient solution of a reaction-diffusion equation to approach the steady-state solution [A. M. Berezhkovskii, C. Sample, and S. Y. Shvartsman, Biophys. J.BIOJAU0006-349510.1016/j.bpj.2010.07.045 99, L59 (2010); A. M. Berezhkovskii, C. Sample, and S. Y. Shvartsman, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.83.051906 83, 051906 (2011)]. Such a measure is referred to as a critical time. Here, we show that LAT is, in fact, identical to the concept of mean action time (MAT) that was first introduced by McNabb [A. McNabb and G. C. Wake, IMA J. Appl. Math.IJAMDM0272-496010.1093/imamat/47.2.193 47, 193 (1991)]. Although McNabb's initial argument was motivated by considering the mean particle lifetime (MPLT) for a linear death process, he applied the ideas to study diffusion. We extend the work of these authors by deriving expressions for the MAT for a general one-dimensional linear advection-diffusion-reaction problem. Using a combination of continuum and discrete approaches, we show that MAT and MPLT are equivalent for certain uniform-to-uniform transitions; these results provide a practical interpretation for MAT by directly linking the stochastic microscopic processes to a meaningful macroscopic time scale. We find that for more general transitions, the equivalence between MAT and MPLT does not hold. Unlike other critical time definitions, we show that it is possible to evaluate the MAT without solving the underlying partial differential equation (pde). This makes MAT a simple and attractive quantity for practical situations. Finally, our work explores the accuracy of certain approximations derived using MAT, showing that useful approximations for nonlinear kinetic processes can be obtained, again without treating the governing pde directly.

  16. Effect of fatigue on reaction time, response time, performance time, and kick impact in taekwondo roundhouse kick.

    Science.gov (United States)

    Sant'Ana, Jader; Franchini, Emerson; da Silva, Vinicius; Diefenthaeler, Fernando

    2017-06-01

    Reaction time and response time are considered important abilities and can potentially affect combat performance. This study investigated the effect of a specific fatigue protocol on reaction time, response time, performance time, and kick impact. Seven male athletes reported to the laboratory on two different days. During day one, athletes performed a specific progressive taekwondo test, and on day two, a protocol for determining reaction time, response time, performance time, and kick impact before and after a time to exhaustion test at an intensity level corresponding to the maximal kick frequency obtained during the specific progressive taekwondo test. Muscle activation from rectus femoris and kick impact of the preferred limb were assessed. No differences were observed for response time and performance time. However, kick impact decreased (43 ± 27 to 13 ± 10 g, p reaction time increased (145 ± 51 to 223 ± 133 ms, p time (r = 0.565; p time (r = 0.494; p time and to reduce fatigue effects in order to improve technique effectiveness and enhance the possibilities of scoring in a competitive situation.

  17. Measuring individual corrective reaction time using the intermittent illumination model.

    Science.gov (United States)

    Lin, Ray F; Hsu, Chih-Hsiang

    2014-01-01

    The corrective reaction time (tcr) is an essential motor property when modelling hand control movements. Many studies designed experiments to estimate tcr, but reported only group means with inconsistent definitions. This study proposes an alternative methodology using Drury's (1994) intermittent illumination model. A total of 24 participants performed circular tracking movements under five levels of visual information delay using a modified monitor in a darkened room. Measured movement speeds and the manipulated delays were used with the model to estimate tcr of individuals and test effects of gender and path width. The results showed excellent model fits and demonstrated individual differences of tcr, which was 273 ms on average and ranged from 87 to 441 ms. The wide range of tcr values was due to significant effects of gender and path width. Male participants required shorter tcr compared to female participants, especially for narrow path widths. This study reports the corrective reaction time (tcr) of individuals using a novel methodology. The estimated tcr ranged from 87 to 441 ms, helping model hand control movements, such as aiming and tracking. The methodology can be continuously applied to study tcr under conditions with various performers and movements.

  18. Waiting for a hand: saccadic reaction time increases in proportion to hand reaction time when reaching under a visuomotor reversal

    Directory of Open Access Journals (Sweden)

    Irene eArmstrong

    2013-07-01

    Full Text Available Although eye movement onset typically precedes hand movement onset when reaching to targets presented in peripheral vision, arm motor commands appear to be issued at around the same time, and possibly in advance, of eye motor commands. A fundamental question, therefore, is whether eye movement initiation is linked or yoked to hand movement. We addressed this issue by having participants reach to targets after adapting to a visuomotor reversal (or 180° rotation between the position of the unseen hand and the position of a cursor controlled by the hand. We asked whether this reversal, which we expected to increase hand reaction time (HRT, would also increase saccadic reaction time (SRT. As predicted, when moving the cursor to targets under the reversal, HRT increased in all participants. SRT also increased in all but one participant, even though the task for the eyes – shifting gaze to the target – was unaltered by the reversal of hand position feedback. Moreover, the effects of the reversal on SRT and HRT were positively correlated across participants; those who exhibited the greatest increases in HRT also showed the greatest increases in SRT. These results indicate that the mechanisms underlying the initiation of eye and hand movements are linked. In particular, the results suggest that the initiation of an eye movement to a manual target depends, at least in part, on the specification of hand movement.

  19. Time-dependent kinetic complexities in cholinesterase-catalyzed reactions.

    Science.gov (United States)

    Masson, P

    2012-10-01

    Cholinesterases (ChEs) display a hysteretic behavior with certain substrates and inhibitors. Kinetic cooperativity in hysteresis of ChE-catalyzed reactions is characterized by a lag or burst phase in the approach to steady state. With some substrates damped oscillations are shown to superimpose on hysteretic lags. These time dependent peculiarities are observed for both butyrylcholinesterase and acetylcholinesterase from different sources. Hysteresis in ChE-catalyzed reactions can be interpreted in terms of slow transitions between two enzyme conformers E and E'. Substrate can bind to E and/or E', both Michaelian complexes ES and Ε'S can be catalytically competent, or only one of them can make products. The formal reaction pathway depends on both the chemical structure of the substrate and the type of enzyme. In particular, damped oscillations develop when substrate exists in different, slowly interconvertible, conformational, and/or micellar forms, of which only the minor form is capable of binding and reacting with the enzyme. Biphasic pseudo-first-order progressive inhibition of ChEs by certain carbamates and organophosphates also fits with a slow equilibrium between two reactive enzyme forms. Hysteresis can be modulated by medium parameters (pH, chaotropic and kosmotropic salts, organic solvents, temperature, osmotic pressure, and hydrostatic pressure). These studies showed that water structure plays a role in hysteretic behavior of ChEs. Attempts to provide a molecular mechanism for ChE hysteresis from mutagenesis studies or crystallographic studies failed so far. In fact, several lines of evidence suggest that hysteresis is controlled by the conformation of His438, a key residue in the catalytic triad of cholinesterases. Induction time may depend on the probability of His438 to adopt the operative conformation in the catalytic triad. The functional significance of ChE hysteresis is puzzling. However, the accepted view that proteins are in equilibrium between

  20. Reaction time and rhythm of movement in Huntington's disease.

    Science.gov (United States)

    Martínez Pueyo, A; García-Ruiz, P J; Feliz, C E; Garcia Caldentey, J; Del Val, J; Herranz, A

    2016-03-15

    Huntington disease (HD) is characterized by several hyperkinesias though motor slowness is also another cardinal in this disease. In addition, self-paced timing movements are also disturbed in HD, which may also affect several rhythmic voluntary movements such as gait. Motor slowness can be measured with clinical scales such as the Unified Huntington's Disease Rating Scale (UHDRS) and timed tests, but also with the reaction time (RT) paradigm. We evaluated RT as a measure of motor slowness in 30 patients with genetically confirmed Huntington's disease and 24 control subjects. We also evaluated self-paced timing precision (SPTP) by applying a simple software program devised by our group. Clinical assessment was performed according to the UHDRS, including motor section, total functional capacity (TFC) and cognitive section (verbal fluency test, symbol digit, and Stroop test) The mean values obtained for RT and SPTP were statistically different in HD as compared with those from controls (p<0.0005). We observed a statistically significant correlation between RT and TFC scores (rs=-0.57, p<0.005 Spearman's correlation) and also between SPTP values and TFC scores (rs=-0.40, p<0.05 Spearman's correlation). In addition, RT and SPTP significantly correlated with cognitive scores (including digit symbol, verbal fluency and Stroop tests). Simple tests such as RT and SPTP provide an objective evaluation of motor impairment in HD yielding measures that correlate with clinical assessment and functional disability. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. The Simplest Chronoscope V: A Theory of Dual Primary and Secondary Reaction Time Systems.

    Science.gov (United States)

    Montare, Alberto

    2016-12-01

    Extending work by Montare, visual simple reaction time, choice reaction time, discriminative reaction time, and overall reaction time scores obtained from college students by the simplest chronoscope (a falling meterstick) method were significantly faster as well as significantly less variable than scores of the same individuals from electromechanical reaction timers (machine method). Results supported the existence of dual reaction time systems: an ancient primary reaction time system theoretically activating the V5 parietal area of the dorsal visual stream that evolved to process significantly faster sensory-motor reactions to sudden stimulations arising from environmental objects in motion, and a secondary reaction time system theoretically activating the V4 temporal area of the ventral visual stream that subsequently evolved to process significantly slower sensory-perceptual-motor reactions to sudden stimulations arising from motionless colored objects. © The Author(s) 2016.

  2. A comparative study on visual choice reaction time for different colors in females.

    Science.gov (United States)

    Balakrishnan, Grrishma; Uppinakudru, Gurunandan; Girwar Singh, Gaur; Bangera, Shobith; Dutt Raghavendra, Aswini; Thangavel, Dinesh

    2014-01-01

    Reaction time is one of the important methods to study a person's central information processing speed and coordinated peripheral movement response. Visual choice reaction time is a type of reaction time and is very important for drivers, pilots, security guards, and so forth. Previous studies were mainly on simple reaction time and there are very few studies on visual choice reaction time. The aim of our study was to compare the visual choice reaction time for red, green, and yellow colors of 60 healthy undergraduate female volunteers. After giving adequate practice, visual choice reaction time was recorded for red, green, and yellow colors using reaction time machine (RTM 608, Medicaid, Chandigarh). Repeated measures of ANOVA and Bonferroni multiple comparison were used for analysis and P reaction (P values time for yellow color is more than red and green.

  3. Real-Time Polymerase Chain Reaction: Applications in Diagnostic Microbiology

    Directory of Open Access Journals (Sweden)

    Kordo B. A. Saeed

    2013-11-01

    Full Text Available The polymerase chain reaction (PCR has revolutionized the detection of DNA and RNA. Real-Time PCR (RT-PCR is becoming the gold standard test for accurate, sensitive and fast diagnosis for a large range of infectious agents. Benefits of this procedure over conventional methods for measuring RNA include its sensitivity, high throughout and quantification. RT-PCR assays have advanced the diagnostic abilities of clinical laboratories particularly microbiology and infectious diseases. In this review we would like to briefly discuss RT-PCR in diagnostic microbiology laboratory, beginning with a general introduction to RT-PCR and its principles, setting up an RT PCR, including multiplex systems and the avoidance and remediation of contamination issues. A segment of the review would be devoted to the application of RT-PCR in clinical practice concentrating on its role in the diagnosis and treatment of infectious diseases.

  4. Acute effects of static and dynamic stretching on balance, agility, reaction time and movement time.

    Science.gov (United States)

    Chatzopoulos, Dimitris; Galazoulas, Christos; Patikas, Dimitrios; Kotzamanidis, Christos

    2014-05-01

    The purpose of this study was to compare the acute effects of three different stretching protocols on balance, agility, reaction time and movement time of the upper limbs. Participants were thirty one female high school athletes (age = 17.3 ± 0.5 yr.). All participants performed one of the following protocols on different days: (a) 3 min jogging followed by 7 min static stretching (SS), (b) 3 min jogging followed by 7 min dynamic stretching (DS), and (c) 3 min jogging followed by 7 min of rest (NS). After the protocols participants performed the following tests: dynamic balance, 505 agility test, reaction time (time between a sound stimulus and release of a button) and movement time (movement of the upper extremity over a 0.5 m distance). The order of stretching protocols and performance tests were counterbalanced to avoid carryover effects. Repeated measures analysis of variance revealed significant main effects for all variables except reaction time. The DS protocol compared to SS performed significantly better in balance, agility and movement time. Additionally, the DS protocol compared to NS performed significantly better in agility. According to the results of the study, a DS protocol is more appropriate than SS for activities that require balance, rapid change of running direction (agility) and movement time of the upper extremities. Key pointsStatic stretching has a negative effect on balance and agility performance compared to dynamic stretching.There was no effect of the stretching protocols on reaction time.Dynamic stretching was more effective than static stretching for increasing movement time of the upper extremities.

  5. Factors influencing the latency of simple reaction time

    Directory of Open Access Journals (Sweden)

    David L Woods

    2015-03-01

    Full Text Available Simple reaction time (SRT, the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by computer hardware and software used for SRT measurement. We developed a calibrated and temporally-precise SRT paradigm to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs. Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231 ms, 213 ms when corrected for hardware delays and increased significantly with age (0.55 ms/year, but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT was estimated by subtracting movement-initiation time, measured in a speeded finger-tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms. SRT latencies increased with age while SDT latencies did not. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in those from the Victorian era and that age-related increases in SRT latencies are due primarily to slowed motor output.

  6. Factors influencing the latency of simple reaction time.

    Science.gov (United States)

    Woods, David L; Wyma, John M; Yund, E William; Herron, Timothy J; Reed, Bruce

    2015-01-01

    Simple reaction time (SRT), the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century, who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by the computer hardware and software used for SRT measurement. We developed a calibrated and temporally precise SRT test to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT) was estimated by subtracting movement initiation time, measured in a speeded finger tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms). SRT latencies increased with age while SDT latencies remained stable. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output.

  7. Online psychophysics: reaction time effects in cognitive experiments.

    Science.gov (United States)

    Semmelmann, Kilian; Weigelt, Sarah

    2017-08-01

    Using the Internet to acquire behavioral data is currently on the rise. However, very basic questions regarding the feasibility of online psychophysics are still open. Here, we aimed to replicate five well-known paradigms in experimental psychology (Stroop, Flanker, visual search, masked priming, attentional blink) in three settings (classical "lab", "web-in-lab", "web") to account for possible changes in technology and environment. Lab and web-in-lab data were both acquired in an in-lab setting with lab using "Gold Standard" methods, while web-in-lab used web technology. This allowed for a direct comparison of potential differences in acquisition software. To account for additional environmental differences, the web technology experiments were published online to participate from home (setting web), thereby keeping the software and experimental design identical and only changing the environmental setting. Our main results are: First, we found an expected fixed additive timing offset when using web technology (M = 37 ms, SD = 8.14) and recording online (M = 87 ms, SD = 16.04) in comparison to lab data. Second, all task-specific effects were reproduced except for the priming paradigm, which couldn't be replicated in any setting. Third, there were no differences in error rates, which are independent of the timing offset. This finding further supports the assumption of data equality over all settings. Fourth, we found that browser type might be influencing absolute reaction times. Together, these results contribute to the slowly but steadily growing literature that online psychophysics is a suitable complement - or even substitute - to lab data acquisition.

  8. A comparative study of visual reaction time in table tennis players and healthy controls.

    Science.gov (United States)

    Bhabhor, Mahesh K; Vidja, Kalpesh; Bhanderi, Priti; Dodhia, Shital; Kathrotia, Rajesh; Joshi, Varsha

    2013-01-01

    Visual reaction time is time required to response to visual stimuli. The present study was conducted to measure visual reaction time in 209 subjects, 50 table tennis (TT) players and 159 healthy controls. The visual reaction time was measured by the direct RT computerized software in healthy controls and table tennis players. Simple visual reaction time was measured. During the reaction time testing, visual stimuli were given for eighteen times and average reaction time was taken as the final reaction time. The study shows that table tennis players had faster reaction time than healthy controls. On multivariate analysis, it was found that TT players had 74.121 sec (95% CI 98.8 and 49.4 sec) faster reaction time compared to non-TT players of same age and BMI. Also playing TT has a profound influence on visual reaction time than BMI. Our study concluded that persons involved in sports are having good reaction time as compared to controls. These results support the view that playing of table tennis is beneficial to eye-hand reaction time, improve the concentration and alertness.

  9. Novel chemical kinetics for a single enzyme reaction: relationship between substrate concentration and the second moment of enzyme reaction time.

    Science.gov (United States)

    Jung, Won; Yang, Seongeun; Sung, Jaeyoung

    2010-08-05

    We report a robust quadratic relation between the inverse substrate concentration and the second moment, , of the catalytic turnover time distribution for enzyme reactions. The results hold irrespective of the mechanism and dynamics of the enzyme reaction and suggest a novel single molecule experimental analysis that provides information about reaction processes of the enzyme-substrate complex and ergodicity of the enzyme reaction system, which is beyond the reach of the conventional analysis for the mean reaction time, . It turns out that - 2(2) is linear in inverse substrate concentration for an ergodic homogeneous enzyme system given that the enzyme substrate encounter is a simple rate process, and its value at the high substrate concentration limit provides direct information about if any non-Poisson reaction process of the enzyme-substrate complex. For a nonergodic heterogeneous reaction system, the corresponding quantity becomes a quadratic function of the inverse substrate concentration. This leads us to suggest an ergodicity measure for single enzyme reaction systems. We obtain a simple analytic expression of the randomness parameter for the single catalytic turnover time, which could provide a quantitative explanation about the previously reported randomness data of the beta-galactosidase enzyme. In obtaining the results, we introduce novel chemical kinetics applicable to a non-Poisson reaction network with arbitrary connectivity, as a generalization of the conventional chemical kinetics.

  10. Simple reaction time to the onset of time-varying sounds.

    Science.gov (United States)

    Schlittenlacher, Josef; Ellermeier, Wolfgang

    2015-10-01

    Although auditory simple reaction time (RT) is usually defined as the time elapsing between the onset of a stimulus and a recorded reaction, a sound cannot be specified by a single point in time. Therefore, the present work investigates how the period of time immediately after onset affects RT. By varying the stimulus duration between 10 and 500 msec, this critical duration was determined to fall between 32 and 40 milliseconds for a 1-kHz pure tone at 70 dB SPL. In a second experiment, the role of the buildup was further investigated by varying the rise time and its shape. The increment in RT for extending the rise time by a factor of ten was about 7 to 8 msec. There was no statistically significant difference in RT between a Gaussian and linear rise shape. A third experiment varied the modulation frequency and point of onset of amplitude-modulated tones, producing onsets at different initial levels with differently rapid increase or decrease immediately afterwards. The results of all three experiments results were explained very well by a straightforward extension of the parallel grains model (Miller and Ulrich Cogn. Psychol. 46, 101-151, 2003), a probabilistic race model employing many parallel channels. The extension of the model to time-varying sounds made the activation of such a grain depend on intensity as a function of time rather than a constant level. A second approach by mechanisms known from loudness produced less accurate predictions.

  11. Simple reaction time for broadband sounds compared to pure tones.

    Science.gov (United States)

    Schlittenlacher, Josef; Ellermeier, Wolfgang; Avci, Gül

    2017-02-01

    Although many studies have explored the relation between reaction time (RT) and loudness, including effects of intensity, frequency, and binaural summation, comparable work on spectral summation is rare. However, most real-world sounds are not pure tones and typically have bandwidths covering several critical bands. Since comparing to a 1-kHz pure tone, the reference tone, is important for loudness measurement and standardization, the present work focuses on comparing RTs for broadband noise to those for 1-kHz pure tones in three experiments using different spectral and binaural configurations. The results of Experiments 1 and 2 yield good quantitative agreement with spectral loudness summation models for moderate and high sound pressure levels, measured using both pink noise covering almost the entire hearing range and bandpass-filtered pink noise with different center frequencies. However, at lower levels, the RT measurements yield an interaction of level and bandwidth, which is not in line with loudness scaling data. In Experiment 3, which investigated the binaural summation of broadband sounds, the binaural gain for white noise was determined to be 9 dB, which is somewhat larger than what had been found in previous RT measurements using 1-kHz pure tones.

  12. Can post-error dynamics explain sequential reaction time patterns?

    Directory of Open Access Journals (Sweden)

    Stephanie eGoldfarb

    2012-07-01

    Full Text Available We investigate human error dynamics in sequential two-alternative choice tasks. When subjects repeatedly discriminate between two stimuli, their error rates and mean reaction times (RTs systematically depend on prior sequences of stimuli. We analyze these sequential effects on RTs, separating error and correct responses, and identify a sequential RT tradeoff: a sequence of stimuli which yields a relatively fast RT on error trials will produce a relatively slow RT on correct trials and vice versa. We reanalyze previous data and acquire and analyze new data in a choice task with stimulus sequences generated by a first-order Markov process having unequal probabilities of repetitions and alternations. We then show that relationships among these stimulus sequences and the corresponding RTs for correct trials, error trials, and averaged over all trials are significantly influenced by the probability of alternations; these relationships have not been captured by previous models. Finally, we show that simple, sequential updates to the initial condition and thresholds of a pure drift diffusion model can account for the trends in RT for correct and error trials. Our results suggest that error-based parameter adjustments are critical to modeling sequential effects.

  13. Brake Reaction Time After Ankle and Subtalar Arthroscopy.

    Science.gov (United States)

    Sittapairoj, Tinnart; Anthony, Chris A; Rungprai, Chamnanni; Gao, Yubo; Barg, Alexej; Phisitkul, Phinit

    2017-11-01

    To evaluate preoperative and postoperative brake reaction time (BRT) of patients undergoing right-sided ankle or subtalar arthroscopy. Patients who underwent right-sided ankle or subtalar arthroscopy were evaluated between May 2015 and February 2017. The inclusion criteria consisted of patients older than 18 years who possessed a valid driver's license, primarily drove vehicles that had automatic transmission, and used their right foot to depress the brake pedal. Patients were excluded if they had medical problems that precluded safe and legal driving. An automotive simulation device was used to calculate BRT from all participants. Each patient underwent testing on a computerized driving simulator preoperatively and then postoperatively at 2, 6, and 12 weeks or until their BRT was equal to or less than 0.7 seconds. BRT was defined as the time from stop stimulus until brake depression of 5%. The study enrolled 17 patients and 19 age-matched normal subjects. Patients showed an average BRT at 2 weeks postoperatively (0.57 ± 0.06 seconds) that was greater than the BRT in the control group (0.55 ± 0.06 seconds, P = .84) and lower than the patients' preoperative BRT (0.59 ± 0.06 seconds, P = .08). These BRTs were lower than the 0.70-second BRT threshold for safe driving in the United States. The results of this study show that emergency BRT after right-sided ankle or subtalar arthroscopy improves by 2 weeks after surgery and is under the previously set benchmark of 0.7 seconds. In patients who undergo right-sided ankle or subtalar arthroscopic procedures, it is not unsafe to drive a vehicle at 2 weeks. Level III, retrospective comparative study. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  14. Exploration of Reaction Time: Ideas for an Inquiry Investigation in Physics Education

    Science.gov (United States)

    Brown, Todd; Brown, Katrina; Barnot, Vickilyn

    2012-01-01

    Reaction time, the time between a stimulus and a person's reaction to it, is a concept familiar to most teenagers, particularly in the context of driving. We describe a simple inexpensive activity that utilizes students' creativity and invokes the scientific method in order to explore reaction time. The goal of the activity is to give students a…

  15. Reaction time variability and related brain activity in methamphetamine psychosis.

    Science.gov (United States)

    Fassbender, Catherine; Lesh, Tyler A; Ursu, Stefan; Salo, Ruth

    2015-03-01

    This study investigated the dynamics of cognitive control instability in methamphetamine (MA) abuse, as well its relationship to substance-induced psychiatric symptoms and drug use patterns. We used an ex-Gaussian reaction time (RT) distribution to examine intraindividual variability (IIV) and excessively long RTs (tau) in an individual's RT on a Stroop task in 30 currently drug-abstinent (3 months to 2 years) MA abusers compared with 27 nonsubstance-abusing control subjects. All subjects underwent functional magnetic resonance imaging while performing the Stroop task, which allowed us to measure the relationship between IIV and tau to functional brain activity. Elevated IIV in the MA compared with the control group did not reach significance; however, when the MA group was divided into those subjects who had experienced MA-induced psychosis (MAP+) (n = 19) and those who had not (n = 11), the MAP+ group had higher average IIV compared with the other groups (p < .03). In addition, although control subjects displayed a relationship between IIV and conflict-related brain activity in bilateral prefrontal cortex such that increased IIV was associated with increased activity, the MAP+ group displayed this relationship in right prefrontal cortex only, perhaps reflecting elevated vigilance in the MAP+ group. Greater IIV did not correlate with severity of use or months MA abstinent. No group differences emerged in tau values. These results suggest increased cognitive instability in those MA-dependent subjects who had experienced MA-induced psychosis. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  16. Reaction times and anticipatory skills of karate athletes.

    Science.gov (United States)

    Mori, Shuji; Ohtani, Yoshio; Imanaka, Kuniyasu

    2002-07-01

    Two experiments were conducted to investigate the reaction times (RTs) and anticipation of karate athletes. In Experiment 1, choice RTs and simple RTs were measured with two types of stimuli. One was videotaped scenes of opponent's offensive actions, which simulated the athletes' view in real situations, and the other was static filled circles, or dots. In the choice RT task, participants were required to indicate as soon as possible whether the offensive actions would be aimed at the upper or middle level of their body, or the dot was presented either at a higher or a lower position. In the simple RT task, they were required to respond as soon as possible when the offensive action started from a static display of the opponent's ready stance, or a dot appeared on the display. The results showed significant differences between the karate athletes and the novices in the choice RT task, the difference being more marked for the video stimuli than for the dot stimuli. There was no significant difference in simple RT between the two groups of participants, for either type of stimuli. In Experiment 2, the proportions of correct responses (PCRs) were measured for video stimuli which were cut off at the seventh frame from the onset of the opponent's offensive action. The athletes yielded significantly higher PCRs than the novices. Collectively the results of the two experiments demonstrate the superior anticipatory skills of karate athletes regarding the target area of an opponent's attack (Scott, Williams, & Davids, Studies in perception and action II: Posters presented at the VIIth International conference on Event Perception and Action, Erlbaum, Hillsdale, NJ, 1993, p. 217; Wiiliams & Elliot, Journal of Sport & Exercise Psychology 21 (1999) 362), together with their advantage over novices in non-specific sensory functions (e.g., vertical discrimination).

  17. Reaction time and anticipatory skill of athletes in open and closed skill-dominated sport.

    Science.gov (United States)

    Nuri, Leila; Shadmehr, Azadeh; Ghotbi, Nastaran; Attarbashi Moghadam, Behrouz

    2013-01-01

    In sports, reaction time and anticipatory skill are critical aspects of perceptual abilities. To date, no study has compared reaction time and anticipatory skill of athletes from open and closed skill-dominated sport. Accordingly, the present study investigated whether a difference exists in sensory-cognitive skills between these two different sport domains. Eleven volleyball players and 11 sprinters participated in this experiment. Reaction time and anticipatory skill of both groups were recorded by a custom-made software called SART (speed anticipation and reaction time test). This software consists of six sensory-cognitive tests that evaluate visual choice reaction time, visual complex choice reaction time, auditory choice reaction time, auditory complex choice reaction time, and anticipatory skill of the high speed and low speed of the ball. For each variable, an independent t-test was performed. Results suggested that sprinters were better in both auditory reaction times (Pvolleyball players were better in both anticipatory skill tests (P = 0.007 and P = 0.04 for anticipatory skill of the high speed and low speed of the ball, respectively). However, no significant differences were found in both visual choice reaction time tests (P > 0.05 for both visual reaction time tests). It is concluded that athletes have greater sensory-cognitive skills related to their specific sport domain either open or closed.

  18. Effect of Nicotine on Audio and Visual Reaction Time in Dipping ...

    African Journals Online (AJOL)

    Nicotine through blood is harmful and as there are fewer studies in India with respect to nicotines influence on reaction time especially in the smokeless tobacco users we studied this. Reaction time is a measure of the sensorimotor integration in a person. We used a PC 1000 Hz reaction timer to record the audio and visual ...

  19. Genetic and environmental contributions to the associations between intraindividual variability in reaction time and cognitive function.

    Science.gov (United States)

    Finkel, Deborah; Pedersen, Nancy L

    2014-01-01

    Intraindividual variability (IIV) in reaction time has been related to cognitive decline, but questions remain about the nature of this relationship. Mean and range in movement and decision time for simple reaction time were available from 241 individuals aged 51-86 years at the fifth testing wave of the Swedish Adoption/Twin Study of Aging. Cognitive performance on four factors was also available: verbal, spatial, memory, and speed. Analyses indicated that range in reaction time could be used as an indicator of IIV. Heritability estimates were 35% for mean reaction and 20% for range in reaction. Multivariate analysis indicated that the genetic variance on the memory, speed, and spatial factors is shared with genetic variance for mean or range in reaction time. IIV shares significant genetic variance with fluid ability in late adulthood, over and above and genetic variance shared with mean reaction time.

  20. Timing of Gun Fire Influences Sprinters’ Multiple Joint Reaction Times of Whole Body in Block Start

    Directory of Open Access Journals (Sweden)

    Mitsuo Otsuka

    2017-05-01

    Full Text Available Experienced sprinters are specifically adapted to pre-planning an advanced motor program. Herein, sprinters are able to immediately accelerate their center of mass forward with a whole-body coordinated motion, following a steady state crouched position. We examined the effect of variable timing of reaction signals on multiple joint reaction times (RT and whole-body RT for specialist sprinters. Twenty well-experienced male sprinters performed five start-dashes from a block start under five variable foreperiod (FP length conditions (1.465, 1.622, 1.780, 1.938, and 2.096 s, with trials randomly timed between a warning and an imperative tone. Participants’ sprinting motion and ground reaction forces of their four limbs during the block start were measured simultaneously. Whole-body RT was significantly shorter when FP length was longer; the values of whole-body RT were 117 ± 5 ms, 129 ± 5 ms, 125 ± 4 ms, 133 ± 6 ms, and 156 ± 8 ms in the 2.096, 1.938, 1.780, 1.622, and 1.465-s FP-length conditions, respectively. A repeated-measures analysis of variance found a significant joint-by-FP length interaction in joint-moment RT. These findings suggest that FP length affects coordinated motion in four limbs and whole-body RT. This information will be able to lead to new methods for start signals in sprint running events and advance our understanding of the association between FP length and dynamic coordinated motion.

  1. Locus of the intensity effect in simple reaction time tasks

    NARCIS (Netherlands)

    Jaśkowski, Piotr; Kurczewska, Marta; Nowik, Agnieszka; van der Lubbe, Robert Henricus Johannes; Verleger, Rolf

    2007-01-01

    Evidence is still inconclusive regarding the locus of the stimulus intensity effect on information processing in reaction tasks. Miller, Ulrich, and Rinkenauer (1999) addressed this question by assessing the intensity effect on stimulus- and response-locked lateralized readiness potentials (LRPs) as

  2. Effect of Grain Size and Reaction Time in Characterisation of Aggregates for Alkali Silica Reaction Using Chemical Method

    Directory of Open Access Journals (Sweden)

    R.P. Pathak

    2016-04-01

    Full Text Available Concrete can deteriorate as a result of alkali aggregate reaction, an interaction between alkalis present in alkaline pore solution originating from the Portland cement and reactive minerals in certain types of aggregates. Potential reactivity of aggregates with regard to alkalis present in concrete mix can be determined by Mortar Bar method, Chemical Method and Petrographic analysis. Of these the chemical method though is quick and does not require a large quantity of material for testing yet have its own inherent limitations. It does not ensure completion of reaction as the observations are limited to 24hour only and also does not assess the effect of varying the combination of coarse and fine aggregates. A study on chemical method by allowing the reaction for a prolonged time up to 96 hours and also on different grain size ranged matrix was carried at Central Soil and Materials Research Station, New Delhi. Simultaneously the test results of the modified method are compared to the existing Mortar Bar method, Chemical Method and Petrographic analysis The outcome of the studies clearly reflects that the grain size play an important role in the reaction, the reaction time has a demarked impact on reactivity, in the cases having a high value of silica release the choice of reduction in alkalinity as an indicator of degree of reaction is not reliable, instead measuring remaining Na2O concentration in Sodium hydroxide solution after the reaction seems to be much more meaningful in justifying the silica release.

  3. The immediate effects of keyboard-based music therapy on probe reaction time.

    Science.gov (United States)

    Zhang, Xiaoying; Zhou, Yue; Liu, Songhuai

    2016-07-01

    [Purpose] This study examined the immediate effects of keyboard-based music therapy on Probe Reaction Time. [Subjects and Methods] Probe Reaction Time was determined in 10 subjects by self-evaluation before and after music therapy intervention. The Probe Reaction Time was separately measured 4 times. [Results] After completion of music therapy intervention, the Probe Reaction Time in the 10 subjects was significantly decreased. [Conclusion] The results suggest that keyboard-based music therapy is an effective and novel treatment, and should be applied in clinical practice.

  4. Factoring out nondecision time in choice reaction time data: Theory and implications.

    Science.gov (United States)

    Verdonck, Stijn; Tuerlinckx, Francis

    2016-03-01

    Choice reaction time (RT) experiments are an invaluable tool in psychology and neuroscience. A common assumption is that the total choice response time is the sum of a decision and a nondecision part (time spent on perceptual and motor processes). While the decision part is typically modeled very carefully (commonly with diffusion models), a simple and ad hoc distribution (mostly uniform) is assumed for the nondecision component. Nevertheless, it has been shown that the misspecification of the nondecision time can severely distort the decision model parameter estimates. In this article, we propose an alternative approach to the estimation of choice RT models that elegantly bypasses the specification of the nondecision time distribution by means of an unconventional convolution of data and decision model distributions (hence called the D*M approach). Once the decision model parameters have been estimated, it is possible to compute a nonparametric estimate of the nondecision time distribution. The technique is tested on simulated data, and is shown to systematically remove traditional estimation bias related to misspecified nondecision time, even for a relatively small number of observations. The shape of the actual underlying nondecision time distribution can also be recovered. Next, the D*M approach is applied to a selection of existing diffusion model application articles. For all of these studies, substantial quantitative differences with the original analyses are found. For one study, these differences radically alter its final conclusions, underlining the importance of our approach. Additionally, we find that strongly right skewed nondecision time distributions are not at all uncommon. (c) 2016 APA, all rights reserved).

  5. Optimal multisensory decision-making in a reaction-time task.

    Science.gov (United States)

    Drugowitsch, Jan; DeAngelis, Gregory C; Klier, Eliana M; Angelaki, Dora E; Pouget, Alexandre

    2014-06-14

    Humans and animals can integrate sensory evidence from various sources to make decisions in a statistically near-optimal manner, provided that the stimulus presentation time is fixed across trials. Little is known about whether optimality is preserved when subjects can choose when to make a decision (reaction-time task), nor when sensory inputs have time-varying reliability. Using a reaction-time version of a visual/vestibular heading discrimination task, we show that behavior is clearly sub-optimal when quantified with traditional optimality metrics that ignore reaction times. We created a computational model that accumulates evidence optimally across both cues and time, and trades off accuracy with decision speed. This model quantitatively explains subjects's choices and reaction times, supporting the hypothesis that subjects do, in fact, accumulate evidence optimally over time and across sensory modalities, even when the reaction time is under the subject's control.

  6. Reaction Time and Joint Kinematics during Functional Movement in Recently Concussed Individuals.

    Science.gov (United States)

    Lynall, Robert C; Blackburn, J Troy; Guskiewicz, Kevin M; Marshall, Stephen W; Plummer, Prudence; Mihalik, Jason P

    2018-01-11

    To compare movement reaction time and joint kinematics between recently concussed and matched control recreational athletes during 3 functional tasks. Cross-sectional. Laboratory. Thirty college-aged recreational athletes comprising two groups (15 participants each): 1) Recent concussion group (median time since concussion 126 days, range 28-432 days), and 2) Age- and sex-matched control group with no recent concussions. We investigated movement reaction time and joint kinematics during 3 tasks: 1) Jump-landing, 2) Anticipated-cut, and 3) Unanticipated-cut. Reaction time and reaction time cost (reaction timejump landing-reaction timecut/reaction timejump landingx100%), along with trunk, hip, and knee joint angles in the sagittal and frontal planes at initial ground contact. There were no reaction time between-group differences, but the control group displayed improved reaction time cost (10.7%) during anticipated cutting as compared to the concussed group (0.8%; p=0.030). The control group displayed less trunk flexion than the concussed group during the non-dominant anticipated cut (5.1° difference; p=0.022). There were no other kinematic between-group differences (p≥0.079). We observed subtle reaction time and kinematic differences between recently concussed and non-concussed individuals more than a month after return-to-activity following concussion. The clinical interpretation of these findings remains unclear, but may have future implications for post-concussion management and rehabilitation. Copyright © 2018. Published by Elsevier Inc.

  7. Effects of reaction time variability and age on brain activity during Stroop task performance.

    Science.gov (United States)

    Tam, Angela; Luedke, Angela C; Walsh, Jeremy J; Fernandez-Ruiz, Juan; Garcia, Angeles

    2015-09-01

    Variability in reaction time during task performance may reflect fluctuations in attention and cause reduced performance in goal-directed tasks, yet it is unclear whether the mechanisms behind this phenomenon change with age. Using fMRI, we tested young and cognitively healthy older adults with the Stroop task to determine whether aging affects the neural mechanisms underlying intra-individual reaction time variability. We found significant between-group differences in BOLD activity modulated by reaction time. In older adults, longer reaction times were associated with greater activity in frontoparietal attentional areas, while in younger adults longer reaction times were associated with greater activity in default mode network areas. Our results suggest that the neural correlates of reaction time variability change with healthy aging, reinforcing the concept of functional plasticity to maintain high cognitive function throughout the lifespan.

  8. Vestibular stimulation after head injury: effect on reaction times and motor speech parameters

    DEFF Research Database (Denmark)

    Engberg, A

    1989-01-01

    Earlier studies by other authors indicate that vestibular stimulation may improve attention and dysarthria in head injured patients. In the present study of five severely head injured patients and five controls, the effect of vestibular stimulation on reaction times (reflecting attention) and some...... motor speech parameters (reflecting dysarthria) was investigated. After eight weeks with regular stimulation, it was concluded that reaction time changes were individual and consistent for a given subject. Only occasionally were they shortened after stimulation. However, reaction time was lengthened...

  9. Reaction times and face discrimination with emotional content

    Directory of Open Access Journals (Sweden)

    ANA MARÍA MARTÍNEZ

    2002-07-01

    Full Text Available Sixty-two university subjects students located in two groups, with a stocking of age of 21.6 for thegroup of women and 22 for the group of men with the purpose to carry out a study upon visual timesof reaction TRV with emotional content keeping in mind the position: start, half and end; the emotionalcontent: neutral, friendly and threatening; and the combinations of the stimuli. The group of womenI present TR more prolonged than that of the men in all the experimental conditions. Also it wasobserved, that more are prolonged when the stimulus to discriminate this located in the half so muchin men as women.

  10. Application of the Law of Additive Reaction Times to Fluid-Solid Reactions in Porous Pellets with Changing Effective Diffusivity

    Science.gov (United States)

    Sohn, Hong Yong; Perez-Fontes, Silvia E.

    2010-12-01

    An approximate closed-form solution, which is based on the Law of Additive Reaction Times for a fluid-solid reaction formulated previously, is presented for the reaction of a fluid with a porous solid in which there is a change of porosity and, thus, effective diffusivity during the reaction. The proposed solution was compared with exact solutions reported in the literature in terms of the effects of various parameters on the fractional conversion. The closed-form expression was found to give satisfactory results and, thus, makes it unnecessary to use a numerical solution. This study represents another of many examples in which Sohn’s Law has provided useful closed-form solutions.

  11. Reaction and Movement Time as a Function of Age and Physical Activity Level

    Science.gov (United States)

    Spirduso, Waneen Wyrick

    1975-01-01

    This sample reaction time, discrimination reaction time and the movement time of older men who have experienced a life style of chronic physical activity were compared to those of nonactive men of similar age and also to active and nonactive young men. (Author)

  12. The time window of multisensory integration: relating reaction times and judgments of temporal order.

    Science.gov (United States)

    Diederich, Adele; Colonius, Hans

    2015-04-01

    Even though visual and auditory information of 1 and the same event often do not arrive at the sensory receptors at the same time, due to different physical transmission times of the modalities, the brain maintains a unitary perception of the event, at least within a certain range of sensory arrival time differences. The properties of this "temporal window of integration" (TWIN), its recalibration due to task requirements, attention, and other variables, have recently been investigated intensively. Up to now, however, there has been no consistent definition of "temporal window" across different paradigms for measuring its width. Here we propose such a definition based on our TWIN model (Colonius & Diederich, 2004). It applies to judgments of temporal order (or simultaneity) as well as to reaction time (RT) paradigms. Reanalyzing data from Mégevand, Molholm, Nayak, & Foxe (2013) by fitting the TWIN model to data from both paradigms, we confirmed the authors' hypothesis that the temporal window in an RT task tends to be wider than in a temporal-order judgment (TOJ) task. This first step toward a unified concept of TWIN should be a valuable tool in guiding investigations of the neural and cognitive bases of this so-far-somewhat elusive concept. (c) 2015 APA, all rights reserved).

  13. The effect of an acute ingestion of Turkish coffee on reaction time and time trial performance.

    Science.gov (United States)

    Church, David D; Hoffman, Jay R; LaMonica, Michael B; Riffe, Joshua J; Hoffman, Mattan W; Baker, Kayla M; Varanoske, Alyssa N; Wells, Adam J; Fukuda, David H; Stout, Jeffrey R

    2015-01-01

    The purpose of this study was to examine the ergogenic benefits of Turkish coffee consumed an hour before exercise. In addition, metabolic, cardiovascular, and subjective measures of energy, focus and alertness were examined in healthy, recreationally active adults who were regular caffeine consumers (>200 mg per day). Twenty males (n = 10) and females (n = 10), age 24.1 ± 2.9 y; height 1.70 ± 0.09 m; body mass 73.0 ± 13.0 kg (mean ± SD), ingested both Turkish coffee [3 mg · kg(-1) BW of caffeine, (TC)], and decaffeinated Turkish coffee (DC) in a double-blind, randomized, cross-over design. Performance measures included a 5 km time trial, upper and lower body reaction to visual stimuli, and multiple object tracking. Plasma caffeine concentrations, blood pressure (BP), heart rate and subjective measures of energy, focus and alertness were assessed at baseline (BL), 30-min following coffee ingestion (30+), prior to endurance exercise (PRE) and immediately-post 5 km (IP). Metabolic measures [VO2, V E , and respiratory exchange rate (RER)] were measured during the 5 km. Plasma caffeine concentrations were significantly greater during TC (p  0.05) were noted in any of the other performance or metabolic measures. Acute ingestion of TC resulted in a significant elevation in plasma caffeine concentrations within 30-min of consumption. TC ingestion resulted in significant performance benefits in reaction time and an increase in subjective feelings of energy in habitual caffeine users. No significant differences were noted in time for the 5 km between trials, however 60 % of the participants performed the 5 km faster during the TC trial and were deemed responders. When comparing TC to DC in responders only, significantly faster times were noted when consuming TC compared to DC. No significant benefits were noted in measures of cognitive function.

  14. Competitive autocatalytic reactions in chaotic flows with diffusion: Prediction using finite-time Lyapunov exponents

    Energy Technology Data Exchange (ETDEWEB)

    Schlick, Conor P., E-mail: conorschlick2015@u.northwestern.edu [Department of Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois 60208 (United States); Umbanhowar, Paul B. [Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Ottino, Julio M. [Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); The Northwestern Institute on Complex Systems (NICO), Northwestern University, Evanston, Illinois 60208 (United States); Lueptow, Richard M., E-mail: r-lueptow@northwestern.edu [Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); The Northwestern Institute on Complex Systems (NICO), Northwestern University, Evanston, Illinois 60208 (United States)

    2014-03-15

    We investigate chaotic advection and diffusion in autocatalytic reactions for time-periodic sine flow computationally using a mapping method with operator splitting. We specifically consider three different autocatalytic reaction schemes: a single autocatalytic reaction, competitive autocatalytic reactions, which can provide insight into problems of chiral symmetry breaking and homochirality, and competitive autocatalytic reactions with recycling. In competitive autocatalytic reactions, species B and C both undergo an autocatalytic reaction with species A such that A+B→2B and A+C→2C. Small amounts of initially spatially localized B and C and a large amount of spatially homogeneous A are advected by the velocity field, diffuse, and react until A is completely consumed and only B and C remain. We find that local finite-time Lyapunov exponents (FTLEs) can accurately predict the final average concentrations of B and C after the reaction completes. The species that starts in the region with the larger FTLE has, with high probability, the larger average concentration at the end of the reaction. If B and C start in regions with similar FTLEs, their average concentrations at the end of the reaction will also be similar. When a recycling reaction is added, the system evolves towards a single species state, with the FTLE often being useful in predicting which species fills the entire domain and which is depleted. The FTLE approach is also demonstrated for competitive autocatalytic reactions in journal bearing flow, an experimentally realizable flow that generates chaotic dynamics.

  15. In Reaction to Columbine, "Times" Focuses on Culture of Violence.

    Science.gov (United States)

    Donofrio, Leana; Richards, Megan

    1999-01-01

    Describes how "The Lakewood Times" (Lakewood, Ohio) covered the shootings at Columbine High School. Suggests that the newspaper covered the story differently than other media by taking many different angles to the story. (RS)

  16. A Joint Modeling Approach for Reaction Time and Accuracy in Psycholinguistic Experiments

    Science.gov (United States)

    Loeys, T.; Rosseel, Y.; Baten, K.

    2011-01-01

    In the psycholinguistic literature, reaction times and accuracy can be analyzed separately using mixed (logistic) effects models with crossed random effects for item and subject. Given the potential correlation between these two outcomes, a joint model for the reaction time and accuracy may provide further insight. In this paper, a Bayesian…

  17. Temporal Frequency Modulates Reaction Time Responses to First-Order and Second-Order Motion

    Science.gov (United States)

    Hutchinson, Claire V.; Ledgeway, Tim

    2010-01-01

    This study investigated the effect of temporal frequency and modulation depth on reaction times for discriminating the direction of first-order (luminance-defined) and second-order (contrast-defined) motion, equated for visibility using equal multiples of direction-discrimination threshold. Results showed that reaction times were heavily…

  18. Comparing of the Reaction Time in Substance-Dependent and Non-Dependent Individuals

    Directory of Open Access Journals (Sweden)

    Mohammad Narimani

    2012-11-01

    Full Text Available Aim: The aim of this study was to compare the simple, selective, and discrimination reaction time in substance-dependent and non-dependent individuals. Method: In this causal-comparative study, the population included of 425 males (opium and crystal dependents who were referred to addiction rehabilitation centers in Tabriz. By random sampling, 16 opium dependents, 16 crystal dependents, and 16 non-dependent individuals with no history of dependency as the compare group were selected. All groups peered in age, and marital status. For gathering data, “Addicts Admit Questionnaire” and laboratory device known as the "Reaction Time Assay" have been used. Results: The results of this study showed that there are significant differences among all groups in simple reaction time, choice reaction time and reaction time to auditory stimuli, but no significant difference in discrimination reaction time and reaction time to visual stimulus observed. Conclusion: The reaction time of substance-dependent groups is slower than non-dependent groups.

  19. Inter-session reliability and sex-related differences in hamstrings total reaction time, pre-motor time and motor time during eccentric isokinetic contractions in recreational athlete.

    Science.gov (United States)

    Ayala, Francisco; De Ste Croix, Mark; Sainz de Baranda, Pilar; Santonja, Fernando

    2014-04-01

    The purposes were twofold: (a) to ascertain the inter-session reliability of hamstrings total reaction time, pre-motor time and motor time; and (b) to examine sex-related differences in the hamstrings reaction times profile. Twenty-four men and 24 women completed the study. Biceps femoris and semitendinosus total reaction time, pre-motor time and motor time measured during eccentric isokinetic contractions were recorded on three different occasions. Inter-session reliability was examined through typical percentage error (CVTE), percentage change in the mean (CM) and intraclass correlations (ICC). For both biceps femoris and semitendinosus, total reaction time, pre-motor time and motor time measures demonstrated moderate inter-session reliability (CVTE0.7). The results also indicated that, although not statistically significant, women reported consistently longer hamstrings total reaction time (23.5ms), pre-motor time (12.7ms) and motor time (7.5ms) values than men. Therefore, an observed change larger than 5%, 9% and 8% for total reaction time, pre-motor time and motor time respectively from baseline scores after performing a training program would indicate that a real change was likely. Furthermore, while not statistically significant, sex differences were noted in the hamstrings reaction time profile which may play a role in the greater incidence of ACL injuries in women. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. A comparative study of simple auditory reaction time in blind (congenitally) and sighted subjects.

    Science.gov (United States)

    Gandhi, Pritesh Hariprasad; Gokhale, Pradnya A; Mehta, H B; Shah, C J

    2013-07-01

    Reaction time is the time interval between the application of a stimulus and the appearance of appropriate voluntary response by a subject. It involves stimulus processing, decision making, and response programming. Reaction time study has been popular due to their implication in sports physiology. Reaction time has been widely studied as its practical implications may be of great consequence e.g., a slower than normal reaction time while driving can have grave results. To study simple auditory reaction time in congenitally blind subjects and in age sex matched sighted subjects. To compare the simple auditory reaction time between congenitally blind subjects and healthy control subjects. STUDY HAD BEEN CARRIED OUT IN TWO GROUPS: The 1(st) of 50 congenitally blind subjects and 2(nd) group comprises of 50 healthy controls. It was carried out on Multiple Choice Reaction Time Apparatus, Inco Ambala Ltd. (Accuracy±0.001 s) in a sitting position at Government Medical College and Hospital, Bhavnagar and at a Blind School, PNR campus, Bhavnagar, Gujarat, India. Simple auditory reaction time response with four different type of sound (horn, bell, ring, and whistle) was recorded in both groups. According to our study, there is no significant different in reaction time between congenital blind and normal healthy persons. Blind individuals commonly utilize tactual and auditory cues for information and orientation and they reliance on touch and audition, together with more practice in using these modalities to guide behavior, is often reflected in better performance of blind relative to sighted participants in tactile or auditory discrimination tasks, but there is not any difference in reaction time between congenitally blind and sighted people.

  1. Mantra, music and reaction times: a study of its applied aspects

    Directory of Open Access Journals (Sweden)

    Varun Malhotra, Rinku Garg, Usha Dhar, Neera Goel, Yogesh Tripathy, Iram Jaan, Sachit Goyal, Sumit Arora

    2014-11-01

    Full Text Available Aims &Objectives: The mechanism of the effects of music is still under scientific study and needs to be understood in a better way. We designed this study to see how music affects reaction time and concentration. The aim of our study was to study the effect of Gayatri mantra on reaction time. Material and Methods: 30 healthy subjects were selected for the study. Baseline record of Visual online Reaction time test was taken. Online visual reaction time was measured during listening to Gayatri Mantra was taken. Results:The reaction times decreased significantly p<0.001. Conclusion: Listening to music at work area reduces distractions, helps increase concentration and delays fatigue. It can be used to heal tinnitus, as an educational tool to develop children with special needs, Alzheimers disease, to improve motor skills in Parkinsonism and help alleviate pain after surgery.

  2. Reaction time for processing visual stimulus in a computer-assisted rehabilitation environment.

    Science.gov (United States)

    Sanchez, Yerly; Pinzon, David; Zheng, Bin

    2017-10-01

    To examine the reaction time when human subjects process information presented in the visual channel under both a direct vision and a virtual rehabilitation environment when walking was performed. Visual stimulus included eight math problems displayed on the peripheral vision to seven healthy human subjects in a virtual rehabilitation training (computer-assisted rehabilitation environment (CAREN)) and a direct vision environment. Subjects were required to verbally report the results of these math calculations in a short period of time. Reaction time measured by Tobii Eye tracker and calculation accuracy were recorded and compared between the direct vision and virtual rehabilitation environment. Performance outcomes measured for both groups included reaction time, reading time, answering time and the verbal answer score. A significant difference between the groups was only found for the reaction time (p = .004). Participants had more difficulty recognizing the first equation of the virtual environment. Participants reaction time was faster in the direct vision environment. This reaction time delay should be kept in mind when designing skill training scenarios in virtual environments. This was a pilot project to a series of studies assessing cognition ability of stroke patients who are undertaking a rehabilitation program with a virtual training environment. Implications for rehabilitation Eye tracking is a reliable tool that can be employed in rehabilitation virtual environments. Reaction time changes between direct vision and virtual environment.

  3. Voice reaction times with recognition for Commodore computers

    Science.gov (United States)

    Washburn, David A.; Putney, R. Thompson

    1990-01-01

    Hardware and software modifications are presented that allow for collection and recognition by a Commodore computer of spoken responses. Responses are timed with millisecond accuracy and automatically analyzed and scored. Accuracy data for this device from several experiments are presented. Potential applications and suggestions for improving recognition accuracy are also discussed.

  4. Influence of a concurrent cognitive task on foot pedal reaction time following traumatic, unilateral transtibial amputation.

    Science.gov (United States)

    Pauley, Tim; Devlin, Michael

    2011-11-01

    To evaluate the influence of a secondary task on foot pedal reaction time, movement time and total response time in patients with transtibial amputation. Controlled trial without randomization. Ten patients with transtibial amputation and 13 age-matched controls. Foot pedal reaction time and movement time were measured for both legs under simple and dual-task conditions. To evaluate the influence of a secondary task on foot pedal reaction time, movement time and total response time in patients with transtibial amputation. Controlled trial without randomization. Ten patients with transtibial amputation and 13 age-matched controls. Foot pedal reaction time and movement time were measured for both legs under simple and dual-task conditions. While mean simple reaction time was similar for both groups (258 (standard deviation (SD) 53) vs 239 (SD 34) ms), a group by reaction time condition interaction (p transtibial amputation (432 (SD 109)vs 317 (SD 63) ms), apparently affecting the prosthetic and intact legs equally (426 (SD 110) vs 438 (SD 107) ms). Among patients with transtibial amputation faster movement time was achieved with the intact leg (185 (SD 61) vs 232 (SD 58)ms, p transtibial amputation, affecting the prosthetic and intact lower limbs equally.

  5. Substrate-Coated Illumination Droplet Spray Ionization: Real-Time Monitoring of Photocatalytic Reactions.

    Science.gov (United States)

    Zhang, Hong; Li, Na; Zhao, Dandan; Jiang, Jie; You, Hong

    2017-09-01

    Real-time monitoring of photocatalytic reactions facilitates the elucidation of the mechanisms of the reactions. However, suitable tools for real-time monitoring are lacking. Herein, a novel method based on droplet spray ionization named substrate-coated illumination droplet spray ionization (SCI-DSI) for direct analysis of photocatalytic reaction solution is reported. SCI-DSI addresses many of the analytical limitations of electrospray ionization (ESI) for analysis of photocatalytic-reaction intermediates, and has potential for both in situ analysis and real-time monitoring of photocatalytic reactions. In SCI-DSI-mass spectrometry (MS), a photocatalytic reaction occurs by loading sample solutions onto the substrate-coated cover slip and by applying UV light above the modified slip; one corner of this slip adjacent to the inlet of a mass spectrometer is the high-electric-field location for launching a charged-droplet spray. After both testing and optimizing the performance of SCI-DSI, the value of this method for in situ analysis and real-time monitoring of photocatalytic reactions was demonstrated by the removal of cyclophosphamide (CP) in TiO 2 /UV. Reaction times ranged from seconds to minutes, and the proposed reaction intermediates were captured and identified by tandem mass spectrometry. Moreover, the free hydroxyl radical (·OH) was identified as the main radicals for CP removal. These results show that SCI-DSI is suitable for in situ analysis and real-time monitoring of CP removal under TiO 2 -based photocatalytic reactions. SCI-DSI is also a potential tool for in situ analysis and real-time assessment of the roles of radicals during CP removal under TiO 2 -based photocatalytic reactions.Graphical Abstract.

  6. Stochastic modeling of biochemical systems with multistep reactions using state-dependent time delay

    Science.gov (United States)

    Wu, Qianqian; Tian, Tianhai

    2016-08-01

    To deal with the growing scale of molecular systems, sophisticated modelling techniques have been designed in recent years to reduce the complexity of mathematical models. Among them, a widely used approach is delayed reaction for simplifying multistep reactions. However, recent research results suggest that a delayed reaction with constant time delay is unable to describe multistep reactions accurately. To address this issue, we propose a novel approach using state-dependent time delay to approximate multistep reactions. We first use stochastic simulations to calculate time delay arising from multistep reactions exactly. Then we design algorithms to calculate time delay based on system dynamics precisely. To demonstrate the power of proposed method, two processes of mRNA degradation are used to investigate the function of time delay in determining system dynamics. In addition, a multistep pathway of metabolic synthesis is used to explore the potential of the proposed method to simplify multistep reactions with nonlinear reaction rates. Simulation results suggest that the state-dependent time delay is a promising and accurate approach to reduce model complexity and decrease the number of unknown parameters in the models.

  7. Evaluating the Recovery Curve for Clinically Assessed Reaction Time After Concussion.

    Science.gov (United States)

    Del Rossi, Gianluca

    2017-08-01

      A change in reaction time is one of various clinical measures of neurocognitive function that can be monitored after concussion and has been reported to be among the most sensitive indicators of cognitive impairment.   To determine the timeline for clinically assessed simple reaction time to return to baseline after a concussion in high school athletes.   Observational study.   Athletic training room.   Twenty-one high school-aged volunteers.   Participants completed 8 trials of the ruler-drop test during each session. Along with baseline measures, a total of 6 additional test sessions were completed over the course of 4 weeks after a concussion (days 3, 7, 10, 14, 21, and 28).   The mean reaction times calculated for all participants from each of the 7 test sessions were analyzed to assess the change in reaction time over the 7 time intervals.   After a concussion and compared with baseline, simple reaction time was, on average, 26 milliseconds slower at 48 to 72 hours postinjury (P reaction time did not return to baseline levels until day 14 postinjury.   Clinically assessed simple reaction time appeared to return to baseline levels within a timeframe that mirrors other measures of cognitive performance (approximately 14 days).

  8. Spontaneous fluctuations in sensory processing predict within-subject reaction time variability

    Directory of Open Access Journals (Sweden)

    Maria José Ribeiro

    2016-05-01

    Full Text Available When engaged in a repetitive task our performance fluctuates from trial-to-trial. In particular, inter-trial reaction time variability has been the subject of considerable research. It has been claimed to be a strong biomarker of attention deficits, increases with frontal dysfunction, and predicts age-related cognitive decline. Thus, rather than being just a consequence of noise in the system, it appears to be under the control of a mechanism that breaks down under certain pathological conditions. Although the underlying mechanism is still an open question, consensual hypotheses are emerging regarding the neural correlates of reaction time inter-trial intra-individual variability. Sensory processing, in particular, has been shown to covary with reaction time, yet the spatio-temporal profile of the moment-to-moment variability in sensory processing is still poorly characterized. The goal of this study was to characterize the intra-individual variability in the time course of single-trial visual evoked potentials and its relationship with inter-trial reaction time variability. For this, we chose to take advantage of the high temporal resolution of the electroencephalogram (EEG acquired while participants were engaged in a 2-choice reaction time task. We studied the link between single trial event-related potentials (ERPs and reaction time using two different analyses: 1 time point by time point correlation analyses thereby identifying time windows of interest, and 2 correlation analyses between single trial measures of peak latency and amplitude and reaction time. To improve extraction of single trial ERP measures related with activation of the visual cortex, we used an independent component analysis procedure.Our ERP analysis revealed a relationship between the N1 visual evoked potential and reaction time. The earliest time point presenting a significant correlation of its respective amplitude with reaction time occurred 175 ms after stimulus

  9. Spontaneous Fluctuations in Sensory Processing Predict Within-Subject Reaction Time Variability.

    Science.gov (United States)

    Ribeiro, Maria J; Paiva, Joana S; Castelo-Branco, Miguel

    2016-01-01

    When engaged in a repetitive task our performance fluctuates from trial-to-trial. In particular, inter-trial reaction time variability has been the subject of considerable research. It has been claimed to be a strong biomarker of attention deficits, increases with frontal dysfunction, and predicts age-related cognitive decline. Thus, rather than being just a consequence of noise in the system, it appears to be under the control of a mechanism that breaks down under certain pathological conditions. Although the underlying mechanism is still an open question, consensual hypotheses are emerging regarding the neural correlates of reaction time inter-trial intra-individual variability. Sensory processing, in particular, has been shown to covary with reaction time, yet the spatio-temporal profile of the moment-to-moment variability in sensory processing is still poorly characterized. The goal of this study was to characterize the intra-individual variability in the time course of single-trial visual evoked potentials and its relationship with inter-trial reaction time variability. For this, we chose to take advantage of the high temporal resolution of the electroencephalogram (EEG) acquired while participants were engaged in a 2-choice reaction time task. We studied the link between single trial event-related potentials (ERPs) and reaction time using two different analyses: (1) time point by time point correlation analyses thereby identifying time windows of interest; and (2) correlation analyses between single trial measures of peak latency and amplitude and reaction time. To improve extraction of single trial ERP measures related with activation of the visual cortex, we used an independent component analysis (ICA) procedure. Our ERP analysis revealed a relationship between the N1 visual evoked potential and reaction time. The earliest time point presenting a significant correlation of its respective amplitude with reaction time occurred 175 ms after stimulus onset

  10. Donders revisited: Discrete or continuous temporal processing underlying reaction time distributions?

    Science.gov (United States)

    Bao, Yan; Yang, Taoxi; Lin, Xiaoxiong; Pöppel, Ernst

    2016-09-01

    Differences of reaction times to specific stimulus configurations are used as indicators of cognitive processing stages. In this classical experimental paradigm, continuous temporal processing is implicitly assumed. Multimodal response distributions indicate, however, discrete time sampling, which is often masked by experimental conditions. Differences in reaction times reflect discrete temporal mechanisms that are pre-semantically implemented and suggested to be based on entrained neural oscillations. © 2016 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

  11. Choice-reaction time to visual motion with varied levels of simultaneous rotary motion

    Science.gov (United States)

    Clark, B.; Stewart, J. D.

    1974-01-01

    Twelve airline pilots were studied to determine the effects of whole-body rotation on choice-reaction time to the horizontal motion of a line on a cathode-ray tube. On each trial, one of five levels of visual acceleration and five corresponding proportions of rotary acceleration were presented simultaneously. Reaction time to the visual motion decreased with increasing levels of visual motion and increased with increasing proportions of rotary acceleration. The results conflict with general theories of facilitation during double stimulation but are consistent with neural-clock model of sensory interaction in choice-reaction time.

  12. Visual reaction times during prolonged angular acceleration parallel the subjective perception of rotation

    Science.gov (United States)

    Mattson, D. L.

    1975-01-01

    The effect of prolonged angular acceleration on choice reaction time to an accelerating visual stimulus was investigated, with 10 commercial airline pilots serving as subjects. The pattern of reaction times during and following acceleration was compared with the pattern of velocity estimates reported during identical trials. Both reaction times and velocity estimates increased at the onset of acceleration, declined prior to the termination of acceleration, and showed an aftereffect. These results are inconsistent with the torsion-pendulum theory of semicircular canal function and suggest that the vestibular adaptation is of central origin.

  13. A Computational Approach to Increase Time Scales in Brownian Dynamics–Based Reaction-Diffusion Modeling

    Science.gov (United States)

    Frazier, Zachary

    2012-01-01

    Abstract Particle-based Brownian dynamics simulations offer the opportunity to not only simulate diffusion of particles but also the reactions between them. They therefore provide an opportunity to integrate varied biological data into spatially explicit models of biological processes, such as signal transduction or mitosis. However, particle based reaction-diffusion methods often are hampered by the relatively small time step needed for accurate description of the reaction-diffusion framework. Such small time steps often prevent simulation times that are relevant for biological processes. It is therefore of great importance to develop reaction-diffusion methods that tolerate larger time steps while maintaining relatively high accuracy. Here, we provide an algorithm, which detects potential particle collisions prior to a BD-based particle displacement and at the same time rigorously obeys the detailed balance rule of equilibrium reactions. We can show that for reaction-diffusion processes of particles mimicking proteins, the method can increase the typical BD time step by an order of magnitude while maintaining similar accuracy in the reaction diffusion modelling. PMID:22697237

  14. Lying takes time: A meta-analysis on reaction time measures of deception.

    Science.gov (United States)

    Suchotzki, Kristina; Verschuere, Bruno; Van Bockstaele, Bram; Ben-Shakhar, Gershon; Crombez, Geert

    2017-04-01

    Lie detection techniques are frequently used, but most of them have been criticized for the lack of empirical support for their predictive validity and presumed underlying mechanisms. This situation has led to increased efforts to unravel the cognitive mechanisms underlying deception and to develop a comprehensive theory of deception. A cognitive approach to deception has reinvigorated interest in reaction time (RT) measures to differentiate lies from truths and to investigate whether lying is more cognitively demanding than truth telling. Here, we provide the results of a meta-analysis of 114 studies (n = 3307) using computerized RT paradigms to assess the cognitive cost of lying. Results revealed a large standardized RT difference, even after correction for publication bias (d = 1.049; 95% CI [0.930; 1.169]), with a large heterogeneity amongst effect sizes. Moderator analyses revealed that the RT deception effect was smaller, yet still large, in studies in which participants received instructions to avoid detection. The autobiographical Implicit Association Test produced smaller effects than the Concealed Information Test, the Sheffield Lie Test, and the Differentiation of Deception paradigm. An additional meta-analysis (17 studies, n = 348) showed that, like other deception measures, RT deception measures are susceptible to countermeasures. Whereas our meta-analysis corroborates current cognitive approaches to deception, the observed heterogeneity calls for further research on the boundary conditions of the cognitive cost of deception. RT-based measures of deception may have potential in applied settings, but countermeasures remain an important challenge. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. A Novel Assessment of Braking Reaction Time Following THA Using a New Fully Interactive Driving Simulator.

    Science.gov (United States)

    Ruel, Allison V; Lee, Yuo-Yu; Boles, John; Boettner, Friedrich; Su, Edwin; Westrich, Geoffrey H

    2015-07-01

    After total hip replacement surgery, patients are eager to resume the activities of daily life, particularly driving. Most surgeons recommend waiting 6 weeks after surgery to resume driving; however, there is no evidence to indicate that patients cannot resume driving earlier. Our purpose was to evaluate when in the recovery period following THA that patients regain or improve upon their preoperative braking reaction time, allowing them to safely resume driving. We measured and compared pre- and postoperative braking reaction times of 90 patients from 3 different surgeons using a Fully Interactive Driving Simulator (Simulator Systems International, Tulsa, OK). We defined a return to safe braking reaction time as a return to a time value that is either equal to or less than the preoperative braking reaction time. Patients tested at 2 and 3 weeks after surgery had slower braking reaction times than preoperative times by an average of 0.069 and 0.009 s, respectively. At 4 weeks after surgery, however, patients improved their reaction times by 0.035 s (p = 0.0398). In addition, at 2, 3, and 4 weeks postoperatively, the results also demonstrated that patient less than 70 years of age recovered faster. Based upon the results of this study, most patients should be allowed to return to driving 4 weeks following minimally invasive primary total hip arthroplasty.

  16. Thin liquid films with time-dependent chemical reactions sheared by an ambient gas flow

    Science.gov (United States)

    Bender, Achim; Stephan, Peter; Gambaryan-Roisman, Tatiana

    2017-08-01

    Chemical reactions in thin liquid films are found in many industrial applications, e.g., in combustion chambers of internal combustion engines where a fuel film can develop on pistons or cylinder walls. The reactions within the film and the turbulent outer gas flow influence film stability and lead to film breakup, which in turn can lead to deposit formation. In this work we examine the evolution and stability of a thin liquid film in the presence of a first-order chemical reaction and under the influence of a turbulent gas flow. Long-wave theory with a double perturbation analysis is used to reduce the complexity of the problem and obtain an evolution equation for the film thickness. The chemical reaction is assumed to be slow compared to film evolution and the amount of reactant in the film is limited, which means that the reaction rate decreases with time as the reactant is consumed. A linear stability analysis is performed to identify the influence of reaction parameters, material properties, and environmental conditions on the film stability limits. Results indicate that exothermic reactions have a stabilizing effect whereas endothermic reactions destabilize the film and can lead to rupture. It is shown that an initially unstable film can become stable with time as the reaction rate decreases. The shearing of the film by the external gas flow leads to the appearance of traveling waves. The shear stress magnitude has a nonmonotonic influence on film stability.

  17. Efficient Constant-Time Complexity Algorithm for Stochastic Simulation of Large Reaction Networks.

    Science.gov (United States)

    Thanh, Vo Hong; Zunino, Roberto; Priami, Corrado

    2017-01-01

    Exact stochastic simulation is an indispensable tool for a quantitative study of biochemical reaction networks. The simulation realizes the time evolution of the model by randomly choosing a reaction to fire and update the system state according to a probability that is proportional to the reaction propensity. Two computationally expensive tasks in simulating large biochemical networks are the selection of next reaction firings and the update of reaction propensities due to state changes. We present in this work a new exact algorithm to optimize both of these simulation bottlenecks. Our algorithm employs the composition-rejection on the propensity bounds of reactions to select the next reaction firing. The selection of next reaction firings is independent of the number reactions while the update of propensities is skipped and performed only when necessary. It therefore provides a favorable scaling for the computational complexity in simulating large reaction networks. We benchmark our new algorithm with the state of the art algorithms available in literature to demonstrate its applicability and efficiency.

  18. Creation, validation, and reliability of a shooting simulator instrument for reaction time evaluation

    Directory of Open Access Journals (Sweden)

    Ellen dos Santos Soares

    Full Text Available Abstract "Creation, validation, and reliability of a shooting simulator instrument for reaction time evaluation." The aim of this study was to develop, validate, and verify the reliability of a shooting simulator instrument for reaction time evaluation. 90 Santa Maria Air Base military personnel participated on the study. Software was developed for use with an electronic gun where participants performed two shooting task tests: simple reaction time and choice reaction time. The results of concurrent validity were satisfactory, no significant differences were found between the two instruments and good agreement was observed. The reliability results were significant in both tests. The instrument can be used for research purposes, or for the purposes of military training as a simple, low-cost tool involving speed, accuracy, and decision-making shooting tasks.

  19. Delay Activity in Rodent Frontal Cortex During a Simple Reaction Time Task

    National Research Council Canada - National Science Library

    Nandakumar S. Narayanan; Mark Laubach

    2009-01-01

    ...—dorsomedial prefrontal cortex (dmPFC) and motor cortex—during a simple reaction time task. Principal component analysis was used to identify major patterns of delay-related activity in frontal cortex...

  20. Loudness Perception in the Domestic Cat: Reaction Time Estimates of Equal Loudness Contours and Recruitment Effects

    National Research Council Canada - National Science Library

    May, Bradford J; Little, Nicole; Saylor, Stephanie

    2009-01-01

    .... At present, there are no published descriptions of loudness perception in this species. This study used a reaction time task to characterize loudness perception in six behaviorally trained cats...

  1. Design Factors Affecting the Reaction Time for Identifying Toilet Signs: A Preliminary Study.

    Science.gov (United States)

    Chen, Yi-Lang; Sie, Cai-Cin

    2016-04-01

    This study focused on the manner in which design factors affect the reaction time for identifying toilet signs. Taiwanese university students and staff members (50 men, 50 women; M age = 23.5 year, SD = 5.7) participated in the study. The 36 toilet signs were modified on three factors (six presenting styles, two figure-ground exchanges, and three colors), and the reaction time data of all participants were collected when the signs were presented in a simulation onscreen. Participants were quickest when reading Chinese text, followed by graphics and English texts. The findings also showed that men and women had different reaction times across various design combinations. These findings can serve as a reference for practically designing toilet signs, since design factors can lead to difficulties with comprehension based on reaction time measurements. © The Author(s) 2016.

  2. QRTEngine: An easy solution for running online reaction time experiments using Qualtrics

    NARCIS (Netherlands)

    Barnhoorn, Jonathan Sebastiaan; Haasnoot, Erwin; Bocanegra, Bruno R.; van Steenbergen, Henk

    2015-01-01

    Performing online behavioral research is gaining increased popularity among researchers in psychological and cognitive science. However, the currently available methods for conducting online reaction time experiments are often complicated and typically require advanced technical skills. In this

  3. The effect of sleep deprivation on choice reaction time and anaerobic power of college student athletes.

    Science.gov (United States)

    Taheri, Morteza; Arabameri, Elaheh

    2012-03-01

    The aim of this study was to determine the effect of one night's sleep deprivation on anaerobic performance and Reaction time of subjects in the morning of the following day. Eighteen male college student athletes were studied twice in a balanced, randomized design. Subjects were measured for peak power, mean power and Reaction time. The performance showed no significant difference in both tests of anaerobic power (peak power, mean power) over the sleep deprivation period (P= 0.3; P= 0.4 respectively), but reaction time differed significantly from baseline (P=0.003). Results support the hypothesis that sleep serves a function of cognitive restitution, particularly in the maintenance of attentional mechanisms. In the light of the above considerations. It was concluded that short-term sleep deprivation is not effective on anaerobic performance, but adversely affects cognitive function such as Reaction Time.

  4. Entropy-based critical reaction time for mixing-controlled reactive transport

    DEFF Research Database (Denmark)

    Chiogna, Gabriele; Rolle, Massimo

    2017-01-01

    the concentration distribution of the transported species is Gaussian and we observe that, even in case of an instantaneous complete bimolecular reaction, dilution caused by dispersive processes dominates the entropy balance at early times and results in the net increase of the entropy density of a reactive species...... on the dimensionality of the problem, on the stoichiometry of the reaction and on the initial concentrations of the reactants. Furthermore, we provide simple analytical expressions to compute the critical reaction time, i.e., the time at which the critical dilution index is reached, for selected flow configurations....... Our results show that, differently from the critical dilution index, the critical reaction time depends on solute transport processes such as advection and hydrodynamic dispersion....

  5. Neutron Scattering in Hydrogenous Moderators, Studied by Time Dependent Reaction Rate Method

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, L.G.; Moeller, E.; Purohit, S.N.

    1966-03-15

    The moderation and absorption of a neutron burst in water, poisoned with the non-1/v absorbers cadmium and gadolinium, has been followed on the time scale by multigroup calculations, using scattering kernels for the proton gas and the Nelkin model. The time dependent reaction rate curves for each absorber display clear differences for the two models, and the separation between the curves does not depend much on the absorber concentration. An experimental method for the measurement of infinite medium reaction rate curves in a limited geometry has been investigated. This method makes the measurement of the time dependent reaction rate generally useful for thermalization studies in a small geometry of a liquid hydrogenous moderator, provided that the experiment is coupled to programs for the calculation of scattering kernels and time dependent neutron spectra. Good agreement has been found between the reaction rate curve, measured with cadmium in water, and a calculated curve, where the Haywood kernel has been used.

  6. Space and time-resolved probing of heterogeneous catalysis reactions using lab-on-a-chip.

    Science.gov (United States)

    Navin, Chelliah V; Krishna, Katla Sai; Theegala, Chandra S; Kumar, Challa S S R

    2016-03-14

    Probing catalytic reactions on a catalyst surface in real time is a major challenge. Herein, we demonstrate the utility of a continuous flow millifluidic chip reactor coated with a nanostructured gold catalyst as an effective platform for in situ investigation of the kinetics of catalytic reactions by taking 5-(hydroxymethyl)furfural (HMF) to 2,5-furandicarboxylic acid (FDCA) conversion as a model reaction. The idea conceptualized in this paper can not only dramatically change the ability to probe the time-resolved kinetics of heterogeneous catalysis reactions but also used for investigating other chemical and biological catalytic processes, thereby making this a broad platform for probing reactions as they occur within continuous flow reactors.

  7. Modifications of the optimal velocity traffic model to include delay due to driver reaction time

    Science.gov (United States)

    Davis, L. C.

    2003-03-01

    Straightforward inclusion of a delay time due to driver reaction time in the optimal velocity (OV) model reveals an unphysical sensitivity to driver reaction times. For delay times of nearly 1 s, which are typical for most drivers, oscillations in vehicle velocity induced by encountering a slower vehicle grow until limited by non-linear effects. Simulations demonstrate that unrealistically small delay times are needed for lengthy platoons of vehicles to avoid collisions. This is a serious limitation of the OV model. Other models, such as the inertial car-following model, allow somewhat larger delay times, but also show unphysical effects. Modifications of the OV model to overcome this deficiency are demonstrated. In addition, unphysical short-period oscillations of vehicle velocity are eliminated by introducing partial car-following into the model. Traffic jams are caused primarily by the delay due to driver reaction time in the modified OV model.

  8. The Effect of Sleep Deprivation on Choice Reaction Time and Anaerobic Power of College Student Athletes

    OpenAIRE

    Taheri, Morteza; Arabameri, Elaheh

    2012-01-01

    Purpose The aim of this study was to determine the effect of one night's sleep deprivation on anaerobic performance and Reaction time of subjects in the morning of the following day. Methods Eighteen male college student athletes were studied twice in a balanced, randomized design. Subjects were measured for peak power, mean power and Reaction time. Results The performance showed no significant difference in both tests of anaerobic power (peak power, mean power) over the sleep deprivation per...

  9. The sound of a mobile phone ringing affects the complex reaction time of its owner

    OpenAIRE

    Zajdel, Radoslaw; Zajdel, Justyna; Zwolińska, Anna; Śmigielski, Janusz; Beling, Piotr; Cegliński, Tomasz; Nowak, Dariusz

    2012-01-01

    Introduction Mobile phone conversation decreases the ability to concentrate and impairs the attention necessary to perform complex activities, such as driving a car. Does the ringing sound of a mobile phone affect the driver's ability to perform complex sensory-motor activities? We compared a subject's reaction time while performing a test either with a mobile phone ringing or without. Material and methods The examination was performed on a PC-based reaction time self-constructed system React...

  10. The time dependent propensity function for acceleration of spatial stochastic simulation of reaction-diffusion systems

    OpenAIRE

    Fu, J; Wu, S; Li, H; Petzold, LR

    2014-01-01

    The inhomogeneous stochastic simulation algorithm (ISSA) is a fundamental method for spatial stochastic simulation. However, when diffusion events occur more frequently than reaction events, simulating the diffusion events by ISSA is quite costly. To reduce this cost, we propose to use the time dependent propensity function in each step. In this way we can avoid simulating individual diffusion events, and use the time interval between two adjacent reaction events as the simulation stepsize. W...

  11. Acute physical exercise under hypoxia improves sleep, mood and reaction time.

    Science.gov (United States)

    de Aquino-Lemos, Valdir; Santos, Ronaldo Vagner T; Antunes, Hanna Karen Moreira; Lira, Fabio S; Luz Bittar, Irene G; Caris, Aline V; Tufik, Sergio; de Mello, Marco Tulio

    2016-02-01

    This study aimed to assess the effect of two sessions of acute physical exercise at 50% VO2peak performed under hypoxia (equivalent to an altitude of 4500 m for 28 h) on sleep, mood and reaction time. Forty healthy men were randomized into 4 groups: Normoxia (NG) (n = 10); Hypoxia (HG) (n = 10); Exercise under Normoxia (ENG) (n = 10); and Exercise under Hypoxia (EHG) (n = 10). All mood and reaction time assessments were performed 40 min after awakening. Sleep was reassessed on the first day at 14 h after the initiation of hypoxia; mood and reaction time were measured 28 h later. Two sessions of acute physical exercise at 50% VO2peak were performed for 60 min on the first and second days after 3 and 27 h, respectively, after starting to hypoxia. Improved sleep efficiency, stage N3 and REM sleep and reduced wake after sleep onset were observed under hypoxia after acute physical exercise. Tension, anger, depressed mood, vigor and reaction time scores improved after exercise under hypoxia. We conclude that hypoxia impairs sleep, reaction time and mood. Acute physical exercise at 50% VO2peak under hypoxia improves sleep efficiency, reversing the aspects that had been adversely affected under hypoxia, possibly contributing to improved mood and reaction time.

  12. Optimal vibration stimulation to the neck extensor muscles using hydraulic vibrators to shorten saccadic reaction time.

    Science.gov (United States)

    Fujiwara, Katsuo; Kunita, Kenji; Furune, Naoe; Maeda, Kaoru; Asai, Hitoshi; Tomita, Hidehito

    2006-09-01

    Optimal vibration stimulation to the neck extensor muscles using hydraulic vibrators to shorten the saccadic reaction time was examined. Subjects were 14 healthy young adults. Visual targets (LEDs) were located 10 degrees left and right of a central point. The targets were alternately lit for random durations of 2-4 seconds in a resting neck condition and various vibration conditions, and saccadic reaction times were measured. Vibration amplitude was 0.5 mm in every condition. The upper trapezius muscles were vibrated at 40, 60, 80, and 100 Hz in a sub-maximum stretch condition in which the muscles were stretched at 70% of maximum stretch. In addition, the muscles were vibrated at 60 Hz with the muscles maximally stretched, with 70% vertical pressure without stretching, and with vibration applied to the skin in the same area as the muscle vibration. At 60, 80, and 100 Hz at 70% maximum stretch, saccadic reaction time shortened significantly compared with the resting neck condition. However, no significant difference in the reaction time was observed among the frequencies. The saccadic reaction times in the maximum stretch condition, muscle pressure condition, and skin contact condition did not differ significantly from that in the resting neck condition. Vibration stimulation to the trapezius with 60-100 Hz frequencies at 0.5 mm amplitude in the sub-maximum stretch condition was effective for shortening saccadic reaction time. The main mechanism appears to be Ia information originating from the muscle spindle.

  13. Multiplicative processes and power laws in human reaction times derived from hyperbolic functions

    Energy Technology Data Exchange (ETDEWEB)

    Medina, José M., E-mail: jmanuel@fisica.uminho.pt [Center for Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2012-04-09

    In sensory psychophysics reaction time is a measure of the stochastic latency elapsed from stimulus presentation until a sensory response occurs as soon as possible. A random multiplicative model of reaction time variability is investigated for generating the reaction time probability density functions. The model describes a generic class of hyperbolic functions by Piéron's law. The results demonstrate that reaction time distributions are the combination of log-normal with power law density functions. A transition from log-normal to power law behavior is found and depends on the transfer of information in neurons. The conditions to obtain Zipf's law are analyzed. -- Highlights: ► I have examined human reaction time variability by random multiplicative processes. ► A transition from power law to log-normal distributions is described. ► The transition depends on the transfer of information in neurons. ► Zipf's law in reaction time distributions depends on the exponent of Piéron's law.

  14. Reaction time as a measure of enhanced blue-light mediated cognitive function following cataract surgery.

    Science.gov (United States)

    Schmoll, Conrad; Tendo, Christelle; Aspinall, Peter; Dhillon, Bal

    2011-12-01

    Since 2002 the discovery of a novel population of intrinsically photosensitive retinal ganglion cells, expressing the photopigment melanopsin, has attracted broad interest in human blue-light mediated non-visual effects including circadian regulation and cognitive function. Ageing is associated with insomnia and cognitive decline. It has been postulated that reduced blue-light transmission through the formation of cataract impairs melanopsin dependant non-visual brain responses mediated by intrinsically photosensitive retinal ganglion cells. We aimed to establish if any objective improvement in cognition could be demonstrated using a reaction time task (RTT) following cataract surgery and intraocular lens implantation. Following strict inclusion and exclusion criteria, 15 patients (age range 59-87, mean 75.4 years) with bilateral cataract performed the RTT before and after surgery on one eye. The mean and the SD of two modalities of reaction time, namely complex reaction time and simple reaction time, were measured and analysed. Responses became both quicker and more consistent following surgery, with statistically significant improvements in the complex reaction time (p=0.016) and the complex reaction time SD (p=0.055), which were not due to a learning effect or improved vision. The results suggest that improved blue-light transmission following cataract surgery has a beneficial effect on cognitive function. We advocate the RTT as an objective platform for exploring these benefits in large sample randomised controlled trials.

  15. Real-time data acquisition and alerts may reduce reaction time and improve perfusionist performance during cardiopulmonary bypass.

    Science.gov (United States)

    Beck, J R; Fung, K; Lopez, H; Mongero, L B; Argenziano, M

    2015-01-01

    Delayed perfusionist identification and reaction to abnormal clinical situations has been reported to contribute to increased mortality and morbidity. The use of automated data acquisition and compliance safety alerts has been widely accepted in many industries and its use may improve operator performance. A study was conducted to evaluate the reaction time of perfusionists with and without the use of compliance alert. A compliance alert is a computer-generated pop-up banner on a pump-mounted computer screen to notify the user of clinical parameters outside of a predetermined range. A proctor monitored and recorded the time from an alert until the perfusionist recognized the parameter was outside the desired range. Group one included 10 cases utilizing compliance alerts. Group 2 included 10 cases with the primary perfusionist blinded to the compliance alerts. In Group 1, 97 compliance alerts were identified and, in group two, 86 alerts were identified. The average reaction time in the group using compliance alerts was 3.6 seconds. The average reaction time in the group not using the alerts was nearly ten times longer than the group using computer-assisted, real-time data feedback. Some believe that real-time computer data acquisition and feedback improves perfusionist performance and may allow clinicians to identify and rectify potentially dangerous situations. © The Author(s) 2014.

  16. Electrophysiological correlates of changes in reaction time based on stimulus intensity.

    Directory of Open Access Journals (Sweden)

    Bimal Lakhani

    Full Text Available Although reaction time is commonly used as an indicator of central nervous system integrity, little is currently understood about the mechanisms that determine processing time. In the current study, we are interested in determining the differences in electrophysiological events associated with significant changes in reaction time that could be elicited by changes in stimulus intensity. The primary objective is to assess the effect of increasing stimulus intensity on the latency and amplitude of afferent inputs to the somatosensory cortex, and their relation to reaction time.Median nerve stimulation was applied to the non-dominant hand of 12 healthy young adults at two different stimulus intensities (HIGH & LOW. Participants were asked to either press a button as fast as possible with their dominant hand or remain quiet following the stimulus. Electroencephalography was used to measure somatosensory evoked potentials (SEPs and event related potentials (ERPs. Electromyography from the flexor digitorum superficialis of the button-pressing hand was used to assess reaction time. Response time was the time of button press.Reaction time and response time were significantly shorter following the HIGH intensity stimulus compared to the LOW intensity stimulus. There were no differences in SEP (N20 & P24 peak latencies and peak-to-peak amplitude for the two stimulus intensities. ERPs, locked to response time, demonstrated a significantly larger pre-movement negativity to positivity following the HIGH intensity stimulus over the Cz electrode.This work demonstrates that rapid reaction times are not attributable to the latency of afferent processing from the stimulated site to the somatosensory cortex, and those latency reductions occur further along the sensorimotor transformation pathway. Evidence from ERPs indicates that frontal planning areas such as the supplementary motor area may play a role in transforming the elevated sensory volley from the

  17. Choice reaction time in patients with post-operative cognitive dysfunction

    DEFF Research Database (Denmark)

    Steinmetz, J.; Rasmussen, L.S.

    2008-01-01

    BACKGROUND: Post-operative cognitive dysfunction (POCD) is detected by administration of a neuropsychological test battery. Reaction time testing is at present not included as a standard test. Choice reaction time (CRT) data from the first International Study of Post-operative Cognitive Dysfunction...... in nine countries. CRT was measured 52 times using the four boxes test. Patients performed the test before surgery (n=1083), at 1 week (n=926) and at 3 months (n=852) post-operatively. CRT for the individual patient was determined as the median time of correct responses. The usefulness of the CRT...... had a significantly longer CRT. ROC curves revealed that a reaction time of 813 ms was the most appropriate cut-off at 1 week and 762 ms at 3 months but the positive predictive value for POCD was low: 34.4% and 14.7%, respectively. CONCLUSIONS: Post-operative cognitive dysfunction is associated...

  18. Practice effects associated with repeated assessment of a clinical test of reaction time.

    Science.gov (United States)

    Del Rossi, Gianluca; Malaguti, Alfonso; Del Rossi, Samanta

    2014-01-01

    Researchers have confirmed that the ruler-drop test could be included as part of a multifaceted concussion-assessment battery and potentially as a way to track recovery from head injury. However, it is unclear if this clinical test of reaction time would be characterized by inconsistent performance because of practice effects. To determine if the ruler-drop test is susceptible to practice effects after serial administration. Descriptive laboratory study. Sports medicine research laboratory. Forty-three persons (age = 21.8 ± 2.6 years). Ten sessions were completed over 5 weeks. Participants completed 10 trials of the ruler-drop test during each session. The mean reaction times calculated for all participants from each test session were analyzed to determine if there was any meaningful change (ie, improvement) in reaction time over the course of the investigation. Simple reaction time improved (ie, decreased) after repeated administration of the ruler-drop test, and the most pronounced improvement occurred between the first 2 test sessions. Between the first and second test sessions, reaction time decreased by almost 7 milliseconds, and there was an overall improvement of almost 13 milliseconds between the first and tenth sessions. Although the pairwise comparisons between the first and second and the first and third sessions were not significant, the change in mean reaction time between the first session and most of the other sessions was significant. We noted no differences when successive sessions were compared. To prevent practice-related improvements in reaction time, practitioners should allow at least 1 practice session before recording baseline results on the ruler-drop test.

  19. [Reaction times (RTS) and cognitive visual evoked potentials during reading--a compared study].

    Science.gov (United States)

    Dionisie, B; Luca, Veronica

    2011-01-01

    The main aim of the experiment is to prove the Paivio's theory about the concrete-abstract effect. A psychoverbal stimulation interface, created by us, was experimented as an IT extension of an EEG/EMG device dedicated for the human brain Evoked Potentials acquisitions (EPs) and reaction times techniques in reading mechanisms assessment. The shortest reaction time was achieved in tests at which the reading has no access to the meaning of words, for concrete word, in both hemisphere. But, in left hemisphere the reaction times for abstract words was shorter than for the abstract word in right hemisphere. EPs acquisition exhibits more negativity of N400 for concrete word and more reverberation of P650-N750 for abstract words. The difference in mean reaction times sustain the Paivio's theory and the difference in amplitude of N400, P650-N750 for concrete and abstract nouns show that the electric activities of brain are correlated in time and in amplitude with the same effort of processing the words. The psycho-verbal stimulation interface can be used as a medical research tool for studying and assessment the cognitive processes of reading, memory or learning using the endogenous visual event related potentials and the psychometric reaction times.

  20. Time-resolved FTIR emission studies of laser photofragmentation and radical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Leone, S.R. [Univ. of Colorado, Boulder (United States)

    1993-12-01

    Recent studies have focused specifically on collision processes, such as single collision energy transfer, reaction dynamics, and radical reactions. The authors employ novel FTIR techniques in the study of single collision energy transfer processes using translationally fast H atom, as well as radical-radical reactions, e.g. CH{sub 3} + O, CF{sub 3} + H(D), and Cl + C{sub 2}H{sub 5}. The fast atoms permit unique high energy regions of certain transition states of combustion species to be probed for the first time.

  1. An analytic algorithm for the space-time fractional reaction-diffusion equation

    Directory of Open Access Journals (Sweden)

    M. G. Brikaa

    2015-11-01

    Full Text Available In this paper, we solve the space-time fractional reaction-diffusion equation by the fractional homotopy analysis method. Solutions of different examples of the reaction term will be computed and investigated. The approximation solutions of the studied models will be put in the form of convergent series to be easily computed and simulated. Comparison with the approximation solution of the classical case of the studied modeled with their approximation errors will also be studied.

  2. Developmental changes in shortening of pro-saccade reaction time while maintaining neck flexion position.

    Science.gov (United States)

    Kunita, Kenji; Fujiwara, Katsuo; Kiyota, Naoe; Yaguchi, Chie; Kiyota, Takeo

    2018-01-10

    We investigated developmental changes in shortening of pro-saccade reaction time while maintaining neck flexion. Subjects comprised 135 children (3-14 years) and 29 young adults (19-23 years). Children were divided into six groups in 2-year age strata. Pro-saccade reaction tasks for 30 s were performed in neck rest and flexion positions. Reaction times under each position were averaged in every 10-s period. Under neck rest position, reaction time in the 0-10 s period was significantly longer in the 3- to 4-year-old group than in the 5- to 6-year-old group and above. No significant age effect was found for reaction time in the 0-10 s period in the 5- to 6-year-old group and above. Although a significant effect of neck flexion was not observed until the 9- to 10-year-old group, significant shortening of reaction time with neck flexion was found in the 11- to 12-year-old group and above. Furthermore, this shortening was maintained until the first 20-s period in the 11- to 12-year-old group and during the entire 30 s in the 13- to 14-year-old and above. These results suggest that brain activation with the maintenance of neck flexion, related to shortening of the pro-saccade reaction time, was found from a later age of approximately 11 years and above, compared with the age at which information-processing function in the pro-saccade was enhanced. In addition, brain activation with the maintenance of neck flexion was sustained longer with age.

  3. Choice reaction time to visual motion during prolonged rotary motion in airline pilots

    Science.gov (United States)

    Stewart, J. D.; Clark, B.

    1975-01-01

    Thirteen airline pilots were studied to determine the effect of preceding rotary accelerations on the choice reaction time to the horizontal acceleration of a vertical line on a cathode-ray tube. On each trial, one of three levels of rotary and visual acceleration was presented with the rotary stimulus preceding the visual by one of seven periods. The two accelerations were always equal and were presented in the same or opposite directions. The reaction time was found to increase with increases in the time the rotary acceleration preceded the visual acceleration, and to decrease with increased levels of visual and rotary acceleration. The reaction time was found to be shorter when the accelerations were in the same direction than when they were in opposite directions. These results suggest that these findings are a special case of a general effect that the authors have termed 'gyrovisual modulation'.

  4. Gender and age effects on the continuous reaction times method in volunteers and patients with cirrhosis

    DEFF Research Database (Denmark)

    Lauridsen, Mette Enok Munk; Grønbæk, Henning; Næser, Esben

    2012-01-01

    Abstract Minimal hepatic encephalopathy (MHE) is a metabolic brain disorder occurring in patients with liver cirrhosis. MHE lessens a patient's quality of life, but is treatable when identified. The continuous reaction times (CRT) method is used in screening for MHE. Gender and age effects......, identifies brain dysfunction rather than effects of gender and age....... on the CRT method are unknown and may confound the results. The aim of this study was to standardise the CRT method outcomes for age and gender effects. We studied 121 volunteers without known disease and 181 patients with cirrhosis by a CRT test. Reaction time to an auditory signal was measured 100 times...

  5. Mean Transit Time and Mean Residence Time for Linear Diffusion–Convection–Reaction Transport System

    Directory of Open Access Journals (Sweden)

    Jacek Waniewski

    2007-01-01

    Full Text Available Characteristic times for transport processes in biological systems may be evaluated as mean transit times (MTTs (for transit states or mean residence times (MRT (for steady states. It is shown in a general framework of a (linear reaction–diffusion–convection equation that these two times are related. Analytical formulas are also derived to calculate moments of exit time distribution using solutions for a stationary state of the system.

  6. Immediate effects of different treatments for the wrist joints of subdominant hands, using electromechanical reaction time.

    Science.gov (United States)

    Hu, Chunying; Huang, Qiuchen; Yu, Lili; Zhou, Yue; Gu, Rui; Cui, Yao; Ge, Meng; Xu, Yanfeng; Liu, Jianfeng

    2016-08-01

    [Purpose] The aim of this study was to examine the immediate effects of muscle strength training and neuromuscular joint facilitation distal resistance training on wrist joints by using electromechanical reaction time. [Subjects and Methods] The subjects were 12 healthy young people (24.2 ± 3.1 years, 169.7 ± 6.5 cm, 65.3 ± 12.6 kg). Two kinds of isotonic contraction techniques were applied on the wrist joint: the wrist joint extension muscle strength training and the wrist joint extension pattern of neuromuscular joint facilitation. The electromechanical reaction time, premotor time, and motor time of the left upper limb were measured before and after each intervention session of muscle strength training and neuromuscular joint facilitation. [Results] The neuromuscular joint facilitation group showed significant shortening of the electromechanical reaction time and motor time after the intervention. [Conclusion] These results suggest that the electromechanical reaction time and motor time of the wrist joint can be improved by neuromuscular joint facilitation together with proximal resistance training, which can be used as a new form of exercise for improving the functions of subdominant hand wrist joints.

  7. Effects of uncertainty, transmission type, driver age and gender on brake reaction and movement time.

    Science.gov (United States)

    Warshawsky-Livne, Lora; Shinar, David

    2002-01-01

    Braking time (BT) is a critical component in safe driving, and various approaches have been applied to minimize it. This study analyzed the components of BT in order to assess the effects of age, gender, vehicle transmission type, and event uncertainty, on its two primary components, perception-reaction time and brake-movement time. Perception-reaction time and brake-movement time were measured at the onset of lights for 72 subjects in a simulator. The six experimental conditions were three levels of uncertainty conditions (none, some, and some + false alarms) and two types of transmission (manual and automatic). The 72 subjects, half male and half female, were further divided into three age groups (mean of 23, 30, and 62 years). Each subject had 10 trials in each of the three levels of uncertainty conditions. Transmission type did not significantly affect either perception-reaction time or brake-movement time. Perception-reaction time increased significantly from 0.32 to 0.42 s (P car travels 0.25 m in 0.01 s. Consequently, even such small effects multiplied by millions of vehicle-kilometers can contribute to significant savings in lives and damages.

  8. Intra-Individual Reaction Time Variability in Schizophrenia, Depression and Borderline Personality Disorder

    Science.gov (United States)

    Kaiser, Stefan; Roth, Alexander; Rentrop, Mirjam; Friederich, Hans-Christoph; Bender, Stephan; Weisbrod, Matthias

    2008-01-01

    Intra-individual reaction time variability (IIV) in neuropsychological task performance reflects short term fluctuations in performance. Increased IIV has been reported in patients with schizophrenia and could be related to a deficient neural timing mechanism, but the role of IIV in adult patients with other psychiatric disorders has not been…

  9. THE RELATIONSHIP BETWEEN DEPRESSION, ANXIETY AND VISUAL REACTION TIMES IN ATHLETES

    Directory of Open Access Journals (Sweden)

    Hasan Ulas Yavuz

    2012-07-01

    Full Text Available The aim of the study was to evaluate depression, state and trait anxiety scores and visual reaction times, and to define the impact of these variables on each other in swimmers and track and field athletes. One hundred athletes participated in this study including 25 female and 25 male national level swimmers and track and field athletes. Application of Spielberger’s State-Trait Anxiety Inventory, Beck Depression Inventory (BDI and Donder’s Reaction Time Test to all participants revealed no significant relationship among obtained data except for a correlation between state and trait anxiety and depression scores (r =0.53, r=0.73 respectively, p<0.001. The mean trait anxiety score in female athletes was higher than that in males (42.60 ± 8.04 and 38.66 ± 7.13 respectively, p<0.05, whereas no gender differences were found for simple, choice or recognition reaction times and depression or state anxiety scores. Even though clinical depression and anxiety may affect the reaction times in patients, these results suggest that there is no correlation between anxiety and depression scores and reaction times in healthy athletes.

  10. Lifespan development of the bilateral deficit in a simple reaction time task.

    Science.gov (United States)

    Vieluf, Solveig; Aschersleben, Gisa; Panzer, Stefan

    2017-04-01

    Performing an action at a maximum speed or with a maximum strength simultaneously with two limbs leads to a lower performance than the sum of unimanual performances. This phenomenon is known as bilateral deficit. There is some evidence that the bilateral deficit changes over the lifespan, in a way that children and older adults show lower deficits than young adults. Inverse developmental changes of childrens' and older adults' brain structures connecting both hemispheres, i.e., the corpus callosum, might importantly contribute to this phenomenon. The seemingly similar developments have been observed with different experimental protocols in the different age groups, respectively. To test for similarities and differences in changes of the bilateral deficit at critical periods of the lifespan development of bimanual actions, children, young adults, and older adults performed a simple reaction time task uni- and bimanually. Reaction times and the resulting bilateral deficit, as well as reaction time variability were analyzed. As expected, reaction times were different for the young adults between the uni- and the bimanual task. Children and older adults performed both conditions with similar reaction times. However, a difference in the direction of the %bilateral deficit occurred between the two age groups. The findings demonstrated an absence of the bilateral deficit for children, but not for younger and older adults.

  11. Influence of rotating shift work on visual reaction time and visual evoked potential.

    Science.gov (United States)

    R V, Hemamalini; N, Krishnamurthy; A, Saravanan

    2014-10-01

    The present day life style is changing the circadian rhythm of the body especially in rotating night shift workers. The impact of this prolongs their reaction time. Night shift also interferes with the circadian variation of pupil size which may affect the visual evoked potential. To compare the visual reaction time, visual evoked potential (VEP) in rotating night shift workers & day workers and also to correlate the changes in visual reaction time with visual evoked potential. Forty healthy male security guards & staff (25 - 35 y) who did rotating night shifts at least for six months & 40 d workers (25 - 35 y) who did not do night shift in last two years were involved in the study. Visual reaction time and the latency & amplitude of VEP were recorded. Kolmogorov- Smirnov test for normalcy showed the latencies & amplitude of VEP to be normally distributed. Student's unpaired t test showed significant difference (ptime and in the latencies of VEP between night shift & day workers. There was no significant difference in the amplitude of VEP. Night shift workers who are prone to circadian rhythm alteration will have prolonged visual reaction time & visual evoked potential abnormalities. Implementation of Bright Light Therapy would be beneficial to the night shift worker.

  12. Does listening to music with an audio ski helmet impair reaction time to peripheral stimuli?

    Science.gov (United States)

    Ruedl, G; Pocecco, E; Wolf, M; Schöpf, S; Burtscher, M; Kopp, M

    2012-12-01

    With the recent worldwide increase in ski helmet use, new market trends are developing, including audio helmets for listening to music while skiing or snowboarding. The aim of this study was to evaluate whether listening to music with an audio ski helmet impairs reaction time to peripheral stimuli. A within-subjects design study using the Compensatory-Tracking-Test was performed on 65 subjects (36 males and 29 females) who had a mean age of 23.3 ± 3.9 years. Using repeated measures analysis of variance, we found significant differences in reaction times between the 4 test conditions (p=0.039). The lowest mean reaction time (± SE) was measured for helmet use while listening to music (507.9 ± 13.2 ms), which was not different from helmet use alone (514.6 ± 12.5 ms) (p=0.528). However, compared to helmet use while listening to music, reaction time was significantly longer for helmet and ski goggles used together (535.8 ± 14.2 ms, p=0.005), with a similar trend for helmet and ski goggles used together while listening to music (526.9 ± 13.8 ms) (p=0.094). In conclusion, listening to music with an audio ski helmet did not increase mean reaction time to peripheral stimuli in a laboratory setting. © Georg Thieme Verlag KG Stuttgart · New York.

  13. A temperature programmed reaction/single-photon ionization time-of-flight mass spectrometry system for rapid investigation of gas-solid heterogeneous catalytic reactions under realistic reaction conditions

    NARCIS (Netherlands)

    He, Songbo; Cui, Huapeng; Lai, Yulong; Sun, Chenglin; Luo, Sha; Li, Haiyang; Seshan, Kulathuiyer

    2015-01-01

    A Temperature-Programmed Reaction (TPRn)/Single-Photon Ionization Time-of-Flight Mass Spectrometry (SPI-TOF-MS) system is described. The TPRn/SPI-TOF-MS system allows rapid characterization of heterogeneous catalytic reactions under realistic reaction conditions and at the same time allows for the

  14. Caffeine Reduces Reaction Time and Improves Performance in Simulated-Contest of Taekwondo

    Directory of Open Access Journals (Sweden)

    Victor G. F. Santos

    2014-02-01

    Full Text Available The aim of this study was to investigate the effects of caffeine on reaction time during a specific taekwondo task and athletic performance during a simulated taekwondo contest. Ten taekwondo athletes ingested either 5 mg·kg−1 body mass caffeine or placebo and performed two combats (spaced apart by 20 min. The reaction-time test (five kicks “Bandal Tchagui” was performed immediately prior to the first combat and immediately after the first and second combats. Caffeine improved reaction time (from 0.42 ± 0.05 to 0.37 ± 0.07 s only prior to the first combat (P = 0.004. During the first combat, break times during the first two rounds were shorter in caffeine ingestion, followed by higher plasma lactate concentrations compared with placebo (P = 0.029 and 0.014, respectively. During the second combat, skipping-time was reduced, and relative attack times and attack/skipping ratio was increased following ingestion of caffeine during the first two rounds (all P < 0.05. Caffeine resulted in no change in combat intensity parameters between the first and second combat (all P > 0.05, but combat intensity was decreased following placebo (all P < 0.05. In conclusion, caffeine reduced reaction time in non-fatigued conditions and delayed fatigue during successive taekwondo combats.

  15. Poststimulation time interval-dependent effects of motor cortex anodal tDCS on reaction-time task performance.

    Science.gov (United States)

    Molero-Chamizo, Andrés; Alameda Bailén, José R; Garrido Béjar, Tamara; García López, Macarena; Jaén Rodríguez, Inmaculada; Gutiérrez Lérida, Carolina; Pérez Panal, Silvia; González Ángel, Gloria; Lemus Corchero, Laura; Ruiz Vega, María J; Nitsche, Michael A; Rivera-Urbina, Guadalupe N

    2018-01-12

    Anodal transcranial direct current stimulation (tDCS) induces long-term potentiation-like plasticity, which is associated with long-lasting effects on different cognitive, emotional, and motor performances. Specifically, tDCS applied over the motor cortex is considered to improve reaction time in simple and complex tasks. The timing of tDCS relative to task performance could determine the efficacy of tDCS to modulate performance. The aim of this study was to compare the effects of a single session of anodal tDCS (1.5 mA, for 15 min) applied over the left primary motor cortex (M1) versus sham stimulation on performance of a go/no-go simple reaction-time task carried out at three different time points after tDCS-namely, 0, 30, or 60 min after stimulation. Performance zero min after anodal tDCS was improved during the whole course of the task. Performance 30 min after anodal tDCS was improved only in the last block of the reaction-time task. Performance 60 min after anodal tDCS was not significantly different throughout the entire task. These findings suggest that the motor cortex excitability changes induced by tDCS can improve motor responses, and these effects critically depend on the time interval between stimulation and task performance.

  16. Estimating Reaction Rate Coefficients Within a Travel-Time Modeling Framework

    Energy Technology Data Exchange (ETDEWEB)

    Gong, R [Georgia Institute of Technology; Lu, C [Georgia Institute of Technology; Luo, Jian [Georgia Institute of Technology; Wu, Wei-min [Stanford University; Cheng, H. [Stanford University; Criddle, Craig [Stanford University; Kitanidis, Peter K. [Stanford University; Gu, Baohua [ORNL; Watson, David B [ORNL; Jardine, Philip M [ORNL; Brooks, Scott C [ORNL

    2011-03-01

    A generalized, efficient, and practical approach based on the travel-time modeling framework is developed to estimate in situ reaction rate coefficients for groundwater remediation in heterogeneous aquifers. The required information for this approach can be obtained by conducting tracer tests with injection of a mixture of conservative and reactive tracers and measurements of both breakthrough curves (BTCs). The conservative BTC is used to infer the travel-time distribution from the injection point to the observation point. For advection-dominant reactive transport with well-mixed reactive species and a constant travel-time distribution, the reactive BTC is obtained by integrating the solutions to advective-reactive transport over the entire travel-time distribution, and then is used in optimization to determine the in situ reaction rate coefficients. By directly working on the conservative and reactive BTCs, this approach avoids costly aquifer characterization and improves the estimation for transport in heterogeneous aquifers which may not be sufficiently described by traditional mechanistic transport models with constant transport parameters. Simplified schemes are proposed for reactive transport with zero-, first-, nth-order, and Michaelis-Menten reactions. The proposed approach is validated by a reactive transport case in a two-dimensional synthetic heterogeneous aquifer and a field-scale bioremediation experiment conducted at Oak Ridge, Tennessee. The field application indicates that ethanol degradation for U(VI)-bioremediation is better approximated by zero-order reaction kinetics than first-order reaction kinetics.

  17. The Influence of Different Performance Level of Fencers on Simple and Choice Reaction Time

    Directory of Open Access Journals (Sweden)

    Štefan Balkó

    2016-09-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n4p391   In many sport disciplines reaction time plays a key role in the sport performance. It is good to point out for example ball games or fighting sports (fencing, karate etc.. The research is focused on detection of the differences in the simple and choice reaction time during visual stimulation among elite, sub-elite fencers and beginners. For the measurement a Fitrosword device and the SWORD software were used. An additional stimulus was added during measuring which should increase the overall number of stimuli, but shouldn’t force fencer to any reaction whatsoever. The results from presented study can be compared with Hicks law. The next focus of the study was to identify the difference in reaction time during two different movement tasks with different complexity movement requirements. The research was built up on a hypothesis that the results will differ among different performance groups of fencers. The difference however was overt among beginners and elite fencers (p = 0.0088, d = 0.5 in reaction time during different movement tasks (direct hit vs. lunge. The results of this research could be useful to trainers for training process organisation and increase the effectivity of muscle coordination during several movements in fencing.

  18. Sex differences in relations of muscle power, lung function, and reaction time in athletes.

    Science.gov (United States)

    Gursoy, Recep

    2010-06-01

    In an earlier study, relations of nonverbal abilities with several bodily measures such as height, weight, and lung capacity were observed. The present aim was estimation of associations of muscle power and lung function with simple eye-hand reaction time. Sex differences for muscle power were significant even with the covariates of height, weight, and age included; however, these disappeared for lung functions (forced vital capacity and peak expiratory flow) and reaction time. The effects of leg power, forced vital capacity, and peak expiratory flow on the left eye-hand reaction time were significant after adjustment for height, weight, right- and left-hand powers and age. The positive effect of exercise may be especially associated with the right brain activity or left hand speed.

  19. A domain decomposition method for time fractional reaction-diffusion equation.

    Science.gov (United States)

    Gong, Chunye; Bao, Weimin; Tang, Guojian; Jiang, Yuewen; Liu, Jie

    2014-01-01

    The computational complexity of one-dimensional time fractional reaction-diffusion equation is O(N²M) compared with O(NM) for classical integer reaction-diffusion equation. Parallel computing is used to overcome this challenge. Domain decomposition method (DDM) embodies large potential for parallelization of the numerical solution for fractional equations and serves as a basis for distributed, parallel computations. A domain decomposition algorithm for time fractional reaction-diffusion equation with implicit finite difference method is proposed. The domain decomposition algorithm keeps the same parallelism but needs much fewer iterations, compared with Jacobi iteration in each time step. Numerical experiments are used to verify the efficiency of the obtained algorithm.

  20. Early, low-level auditory-somatosensory multisensory interactions impact reaction time speed

    Directory of Open Access Journals (Sweden)

    Holger F Sperdin

    2009-03-01

    Full Text Available Several lines of research have documented early-latency non-linear response interactions between audition and touch in humans and non-human primates. That these effects have been obtained under anesthesia, passive stimulation, as well as speeded reaction time tasks would suggest that some multisensory effects are not directly influencing behavioral outcome. We investigated whether the initial non-linear neural response interactions have a direct bearing on the speed of reaction times. Electrical neuroimaging analyses were applied to event-related potentials (ERPs in response to auditory, somatosensory, or simultaneous auditory-somatosensory multisensory stimulation that were in turn averaged according to trials leading to fast and slow reaction times (using a median split of individual subject data for each experimental condition. Responses to multisensory stimulus pairs were contrasted with each unisensory response as well as summed responses from the constituent unisensory conditions. Behavioral analyses indicated that neural response interactions were only implicated in the case of trials producing fast reaction times, as evidenced by facilitation in excess of probability summation. In agreement, supra-additive non-linear neural response interactions between multisensory and the sum of the constituent unisensory stimuli were evident over the 40-84ms post-stimulus period only when reaction times were fast, whereas subsequent effects (86-128ms were observed independently of reaction time speed. Distributed source estimations further revealed that these earlier effects followed from supra-additive modulation of activity within posterior superior temporal cortices. These results indicate the behavioral relevance of early multisensory phenomena.

  1. Reaction Time Is Negatively Associated with Corpus Callosum Area in the Early Stages of CADASIL.

    Science.gov (United States)

    Delorme, S; De Guio, F; Reyes, S; Jabouley, A; Chabriat, H; Jouvent, E

    2017-11-01

    Reaction time was recently recognized as a marker of subtle cognitive and behavioral alterations in the early clinical stages of CADASIL, a monogenic cerebral small-vessel disease. In unselected patients with CADASIL, brain atrophy and lacunes are the main imaging correlates of disease severity, but MR imaging correlates of reaction time in mildly affected patients are unknown. We hypothesized that reaction time is independently associated with the corpus callosum area in the early clinical stages of CADASIL. Twenty-six patients with CADASIL without dementia (Mini-Mental State Examination score > 24 and no cognitive symptoms) and without disability (modified Rankin Scale score ≤ 1) were compared with 29 age- and sex-matched controls. Corpus callosum area was determined on 3D-T1 MR imaging sequences with validated methodology. Between-group comparisons were performed with t tests or χ2 tests when appropriate. Relationships between reaction time and corpus callosum area were tested using linear regression modeling. Reaction time was significantly related to corpus callosum area in patients (estimate = -7.4 × 103, standard error = 3.3 × 103, P = .03) even after adjustment for age, sex, level of education, and scores of depression and apathy (estimate = -12.2 × 103, standard error = 3.8 × 103, P = .005). No significant relationship was observed in controls. Corpus callosum area, a simple and robust imaging parameter, appears to be an independent correlate of reaction time at the early clinical stages of CADASIL. Further studies will determine whether corpus callosum area can be used as an outcome in future clinical trials in CADASIL or in more prevalent small-vessel diseases. © 2017 by American Journal of Neuroradiology.

  2. Effect of Abstinence on Audio-Visual Reaction Time in Chronic Smokers Pursuing a Professional Course.

    Science.gov (United States)

    Vallath, Aditya Lal; Joshi, Anuradha Rajiv; Vaidya, Savita Madhukar

    2015-12-01

    It has now been proven that tobacco abuse is the leading cause for various carcinomas such as oral, lung and oesophageal. It also leads to atherosclerosis of major vessels, development of hypertension, autoimmune disorders, COPD, bronchitis, asthma, bronchiectasis, etc. Most smokers are dependent on nicotine and abstinence from smoking results in tobacco withdrawal and craving. It also affects cognitive skills and reaction time. Many students in professional college have the habit of smoking. In spite of awareness programmes carried out in schools, colleges and having ban on smoking, prevalence of smoking is rising in India. To observe the effect of abstinence on audiovisual reaction time and to note the cause for reverting to smoking by the students pursing professional course. Sixty male volunteers in the age group of 18-25 years participated in the study. The volunteers were divided in to two groups (control group and study group). Cigarette smokers consuming at least 10-19 cigarettes per day for more than 2-3 years were included as subjects in study group. The study was conducted using a audiovisual reaction time apparatus in a quiet and bright lit room. All volunteers were subjected to baseline readings after demonstrating working of the apparatus. Auditory (high pitched and low pitched sound) and visual (red light and green light) reaction time was recorded. Thirty students in study group were subjected to these tests immediately after smoking and after 12 hours of abstinence. After all the individuals were tested, the recorded values were compared by Student's t-test. Statistically significant difference was recorded in auditory and visual reaction time in study group subjects immediately after smoking and after 12 hours of abstinence as compared to base line readings. It was observed that auditory and visual reaction time was prolonged in chronic smokers after 12 hours of abstinence.

  3. TIMES-SS - A mechanistic evaluation of an external validation study using reaction chemistry principles

    DEFF Research Database (Denmark)

    Roberts, David W.; Patlewicz, Grace; Dimitrov, Sabcho D.

    2007-01-01

    chemicals in the murine local lymph node assay (LLNA) and then compared with predictions made by TIMES-SS. The results were promising with an overall good concordance (83%) between experimental and predicted values. The LLNA results were evaluated with respect to reaction chemistry principles...... for sensitization. Additional testing on a further four chemicals was carried out to explore some of the specific reaction chemistry findings in more detail. Improvements for TIMES-SS, where appropriate, were put forward together with proposals for further research work. TIMES-SS is a promising tool to aid......The TImes MEtabolism Simulator platform used for predicting skin sensitization (TIMES-SS) is a hybrid expert system that was developed at Bourgas University using funding and data from a consortium comprised of industry and regulators. TIMES-SS encodes structure-toxicity and structure...

  4. Postural stability, clicker reaction time and bow draw force predict performance in elite recurve archery.

    Science.gov (United States)

    Spratford, Wayne; Campbell, Rhiannon

    2017-06-01

    Recurve archery is an Olympic sport that requires extreme precision, upper body strength and endurance. The purpose of this research was to quantify how postural stability variables both pre- and post-arrow release, draw force, flight time, arrow length and clicker reaction time, collectively, impacted on the performance or scoring outcomes in elite recurve archery athletes. Thirty-nine elite-level recurve archers (23 male and 16 female; mean age = 24.7 ± 7.3 years) from four different countries volunteered to participate in this study prior to competing at a World Cup event. An AMTI force platform (1000Hz) was used to obtain centre of pressure (COP) measurements 1s prior to arrow release and 0.5s post-arrow release. High-speed footage (200Hz) allowed for calculation of arrow flight time and score. Results identified clicker reaction time, draw force and maximum sway speed as the variables that best predicted shot performance. Specifically, reduced clicker reaction time, greater bow draw force and reduced postural sway speed post-arrow release were predictors of higher scoring shots. It is suggested that future research should focus on investigating shoulder muscle tremors at full draw in relation to clicker reaction time, and the effect of upper body strength interventions (specifically targeting the musculature around the shoulder girdle) on performance in recurve archers.

  5. Minimal hepatic encephalopathy characterized by parallel use of the continuous reaction time and portosystemic encephalopathy tests

    DEFF Research Database (Denmark)

    Lauridsen, M M; Schaffalitzky de Muckadell, O B; Vilstrup, H

    2015-01-01

    based vs. paper and pencil). To compare results of the Continuous Reaction time (CRT) and the Portosystemic Encephalopathy (PSE) tests in a large unselected cohort of cirrhosis patients without clinically detectable brain impairment and to clinically characterize the patients according to their test...... results. The CRT method is a 10-minute computerized test of a patient's motor reaction time stability (CRTindex) to 150 auditory stimuli. The PSE test is a 20-minute paper-pencil test evaluating psychomotor speed. Both tests were performed at the same occasion in 129 patients. Both tests were normal...

  6. The Time Dependent Propensity Function for Acceleration of Spatial Stochastic Simulation of Reaction-Diffusion Systems

    Science.gov (United States)

    Wu, Sheng; Li, Hong; Petzold, Linda R.

    2015-01-01

    The inhomogeneous stochastic simulation algorithm (ISSA) is a fundamental method for spatial stochastic simulation. However, when diffusion events occur more frequently than reaction events, simulating the diffusion events by ISSA is quite costly. To reduce this cost, we propose to use the time dependent propensity function in each step. In this way we can avoid simulating individual diffusion events, and use the time interval between two adjacent reaction events as the simulation stepsize. We demonstrate that the new algorithm can achieve orders of magnitude efficiency gains over widely-used exact algorithms, scales well with increasing grid resolution, and maintains a high level of accuracy. PMID:26609185

  7. Response preparation and intra-individual reaction time variability in schizophrenia.

    Science.gov (United States)

    Dankinas, Denisas; Mėlynytė, Sigita; Šiurkutė, Aldona; Dapšys, Kastytis

    2016-01-01

    Background. It is important to prepare response in advance to increase the efficiency of its execution. The process of response preparation is usually studied using the precueing paradigm. In this paradigm subjects have to employ the preceding information about further imperative stimulus to perform proper response preparation, which shortens the reaction time of subsequent response execution. Previous studies detected the impairment of response preparation in schizophrenia only with the help of electroencephalographic parameters, but not with the assessing of reaction time. Therefore, in this study we attempted to find a behavioural parameter that could detect impairment in response preparation of schizophrenia patients. It was recently found that appropriate response preparation not only shortens the reaction time but also increases its stability, which is measured with the intra-individual reaction time variability. It was also revealed that response stability could better find cognitive dysfunction in some studies of schizophrenia disorder than classical behavioural parameters. Hence, the main goal of this study was to verify if intra-individual reaction time variability could detect the impairment of response preparation in schizophrenia patients. Materials and methods. In order to achieve the main purpose, we carried out a study with 14 schizophrenia patients and 14 control group subjects. We used precueing paradigm in our research, in which participants had to employ information about stimulus probability for the proper response preparation. Results. Our main result showed that despite the responses of schizophrenia patients were faster to the high-probability stimulus than to the low-probability one (F (1, 13) = 30.9, p reaction time variability did not differ in this group between the responses to more and less probable stimuli (F (1, 13) = 0.64, p = 0.44). Conclusions. Results of the study suggest that people with schizophrenia were able to use precueing

  8. Stochastic binary modeling of cells in continuous time as an alternative to biochemical reaction equations.

    Science.gov (United States)

    Teraguchi, Shunsuke; Kumagai, Yutaro; Vandenbon, Alexis; Akira, Shizuo; Standley, Daron M

    2011-12-01

    We have developed a coarse-grained formulation for modeling the dynamic behavior of cells quantitatively, based on stochasticity and heterogeneity, rather than on biochemical reactions. We treat each reaction as a continuous-time stochastic process, while reducing each biochemical quantity to a binary value at the level of individual cells. The system can be analytically represented by a finite set of ordinary linear differential equations, which provides a continuous time course prediction of each molecular state. Here we introduce our formalism and demonstrate it with several examples.

  9. The Time Dependent Propensity Function for Acceleration of Spatial Stochastic Simulation of Reaction-Diffusion Systems.

    Science.gov (United States)

    Fu, Jin; Wu, Sheng; Li, Hong; Petzold, Linda R

    2014-10-01

    The inhomogeneous stochastic simulation algorithm (ISSA) is a fundamental method for spatial stochastic simulation. However, when diffusion events occur more frequently than reaction events, simulating the diffusion events by ISSA is quite costly. To reduce this cost, we propose to use the time dependent propensity function in each step. In this way we can avoid simulating individual diffusion events, and use the time interval between two adjacent reaction events as the simulation stepsize. We demonstrate that the new algorithm can achieve orders of magnitude efficiency gains over widely-used exact algorithms, scales well with increasing grid resolution, and maintains a high level of accuracy.

  10. Analysis of agility, reaction time and balance variables at badminton players aged 9-14 years

    Directory of Open Access Journals (Sweden)

    Seydi Ahmet Ağaoğlu

    2017-12-01

    Full Text Available Aim: The aim of this study was investigated agility, static and dynamic balance and reaction time variables of badminton players aged between 9-14 and relate with among variables. Material and Methods: In Samsun, 19 males (sport age, 3.42±1.64 years and 12 females (3.00±1.28 years active badminton players were voluntarily participated in who are in 9-14 ages range. Agility was measured by “T” test, CSMI-Tecnobody Pk-252 isokinetic balance system measuring instrument was used to test static balance and dynamic balance and Mozart Lafayette reaction measuring instrument was used to test visual and auditory reaction times of players. Spearman correlation analysis was applied so as to correlation analysis. The level of significance was taken as p<0.05. Results: For female athletes, a positive relation was determined between the agility and the perimeter (mm used (r=0.727; p<0.01 through the static balance measure double foot and eyes are open. For male athletes, a positive relation was determined between the visual reaction time and the perimeter (mm used (r=0.725; p<0.01 through the static balance measure dominant foot and eyes are open. For male and female athletes were not found any correlation between reaction time and dynamic balance. Conclusion: It was determined that audio (ears and visual (eyes reaction time was effective on balance. While badminton players are closed eyes, audio sensors are more influence on balance test through measure dominant foot.

  11. OPTIMIZATION OF TIME REACTION AND HYDROXIDE ION CONCENTRATION ON FLAVONOID SYNTHESIS FROM BENZALDEHYDE AND ITS DERIVATIVES

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2010-06-01

    Full Text Available The aim of this research is to determine the optimum time of reaction and concentration of hydroxide ion on chalcone, 4-methoxychalcone and 3,4-dimethoxychalcone synthesis. Chalcone and its derivatives were synthesized by dissolving KOH in ethanol followed by dropwise addition of acetophenone and benzaldehyde. Then, the mixture was stirred for several hours. Three benzaldehydes has been used, i.e : benzaldehyde, p-anysaldehyde and veratraldehyde. The time of reaction was varied for, 12, 18, 24, 30 and 36 hours. Furthermore, on the optimum reaction time for each benzaldehyde the hydroxyl ion concentration was varied from 5,7,9,11 and 13%(w/v. The results of this research suggested that the optimum time of chalchone synthesis was 12 hours, while, 4-methoxychalcone and 3,4-dimethoxychalcone were 30 hours. The optimum concentration of hydroxide ion of chalcone synthesis was 13% and for 4-methoxychalcone and 3,4-dimethoxychalcone were 11%. Keywords: Chalcone synthesis, time of reaction, hydroxide ion concentration.

  12. [Influence of solvent and drug preparation time on Shuanghuanglian injections induce pseudo-allergic reaction].

    Science.gov (United States)

    Yi, Yan; Liang, Ai-hua; Li, Chun-ying; Zhang, Yu-shi; Zhao, Yong; Han, Jia-yin; Lu, Yu-ting

    2015-07-01

    Choosing the right solvent and timely use is the basis of rational drug use and the most direct and efficient way to improve the safety of traditional Chinese medicine injections. This study aimed to evaluate the influence of solvent and drug preparation time on Shuanghuanglian injection inducing pseudo-allergic reactions with mouse mode. The two tests were carried out: (1) Comparative experiment between different solvent: Shuanghuanglian injection preparation to the appropriate concentration with 0.9% sodium chloride injection and 5% dextrose injection, mixed with Evans blue, at one time intravenous injected into mice, 30 minutes later, the mouse ears vascular permeability were observed and compared. (2) Comparative experiment among different preparation time: placed 10 min, 2.5 h, 6 h and 24 h after Shuanghuanglian injection were prepared and then to detect the pseudo-allergic reactions in mice using the same methods as in (1). The results showed that there was no significant difference in the pseudo-allergic reactions in mice which induced by the same dose of Shuanghuanglian injection, respectively with 0.9% sodium chloride injection and 5% dextrose injection preparation, and with the extension of preparation time, the degree of pseudo-allergic reactions of Shuanghuanglian injection was gradually severe.

  13. An analysis on driver drowsiness based on reaction time and EEG band power.

    Science.gov (United States)

    Ruyi Foong; Kai Keng Ang; Chai Quek; Cuntai Guan; Aung Aung Phyo Wai

    2015-08-01

    Falling asleep during driving is a serious problem that has resulted in fatal accidents worldwide. Thus, there is a need to detect driver drowsiness to counter it. This study analyzes the changes in the electroencephalography (EEG) collected from 4 subjects driving under monotonous road conditions using a driving simulator. The drowsiness level of the subjects is inferred from the time taken to react to events. The results from the analysis of the reaction time shows that drowsiness occurs in cycles, which correspond to short sleep cycles known as `microsleeps'. The results from a time-frequency analysis of the four frequency bands' power reveals differences between trials with fast and slow reaction times; greater beta band power is present in all subjects, greater alpha power in 2 subjects, greater theta power in 2 subjects, and greater delta power in 3 subjects, for fast reaction trials. Overall, this study shows that reaction time can be used to infer the drowsiness, and subject-specific changes in the EEG band power may be used to infer drowsiness. Thus the study shows a promising prospect of developing Brain-Computer Interface to detect driver drowsiness.

  14. AN INVESTIGATION OF LEG AND TRUNK STRENGTH AND REACTION TIMES OF HARD-STYLE MARTIAL ARTS PRACTITIONERS

    OpenAIRE

    Oliver O'Donovan; Jeanette Cheung; Maria Catley; Alison H. McGregor; Paul H. Strutton

    2006-01-01

    The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response...

  15. A parametric duration model of the reaction times of drivers distracted by mobile phone conversations.

    Science.gov (United States)

    Haque, Md Mazharul; Washington, Simon

    2014-01-01

    The use of mobile phones while driving is more prevalent among young drivers-a less experienced cohort with elevated crash risk. The objective of this study was to examine and better understand the reaction times of young drivers to a traffic event originating in their peripheral vision whilst engaged in a mobile phone conversation. The CARRS-Q advanced driving simulator was used to test a sample of young drivers on various simulated driving tasks, including an event that originated within the driver's peripheral vision, whereby a pedestrian enters a zebra crossing from a sidewalk. Thirty-two licensed drivers drove the simulator in three phone conditions: baseline (no phone conversation), hands-free and handheld. In addition to driving the simulator each participant completed questionnaires related to driver demographics, driving history, usage of mobile phones while driving, and general mobile phone usage history. The participants were 21-26 years old and split evenly by gender. Drivers' reaction times to a pedestrian in the zebra crossing were modelled using a parametric accelerated failure time (AFT) duration model with a Weibull distribution. Also tested where two different model specifications to account for the structured heterogeneity arising from the repeated measures experimental design. The Weibull AFT model with gamma heterogeneity was found to be the best fitting model and identified four significant variables influencing the reaction times, including phone condition, driver's age, license type (provisional license holder or not), and self-reported frequency of usage of handheld phones while driving. The reaction times of drivers were more than 40% longer in the distracted condition compared to baseline (not distracted). Moreover, the impairment of reaction times due to mobile phone conversations was almost double for provisional compared to open license holders. A reduction in the ability to detect traffic events in the periphery whilst distracted

  16. The cortisol awakening response is associated with performance of a serial sequence reaction time task.

    Science.gov (United States)

    Hodyl, Nicolette A; Schneider, Luke; Vallence, Ann-Maree; Clow, Angela; Ridding, Michael C; Pitcher, Julia B

    2016-02-01

    There is emerging evidence of a relationship between the cortisol awakening response (CAR) and the neural mechanisms underlying learning and memory. The aim of this study was to determine whether the CAR is associated with acquisition, retention and overnight consolidation or improvement of a serial sequence reaction time task. Salivary samples were collected at 0, 15, 30 and 45 min after awakening in 39 healthy adults on 2 consecutive days. The serial sequence reaction time task was repeated each afternoon. Participants completed the perceived stress scale and provided salivary samples prior to testing for cortisol assessment. While the magnitude of the CAR (Z score) was not associated with either baseline performance or the timed improvement during task acquisition of the serial sequence task, a positive correlation was observed with reaction times during the stable performance phase on day 1 (r=0.373, p=0.019). Residuals derived from the relationship between baseline and stable phase reaction times on day 1 were used as a surrogate for the degree of learning: these residuals were also correlated with the CAR mean increase on day 1 (r=0.357, p=0.048). Task performance on day 2 was not associated with the CAR obtained on this same day. No association was observed between the perceived stress score, cortisol at testing or task performance. These data indicate that a smaller CAR in healthy adults is associated with a greater degree of learning and faster performance of a serial sequence reaction time task. These results support recognition of the CAR as an important factor contributing to cognitive performance throughout the day. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Assumption-free analysis of quantitative real-time polymerase chain reaction (PCR) data

    NARCIS (Netherlands)

    Ramakers, Christian; Ruijter, Jan M.; Deprez, Ronald H. Lekanne; Moorman, Antoon F. M.

    2003-01-01

    Quantification of mRNAs using real-time polymerase chain reaction (PCR) by monitoring the product formation with the fluorescent dye SYBR Green I is being extensively used in neurosciences, developmental biology, and medical diagnostics. Most PCR data analysis procedures assume that the PCR

  18. Processing of Emotion Words by Patients with Autism Spectrum Disorders: Evidence from Reaction Times and EEG

    Science.gov (United States)

    Lartseva, Alina; Dijkstra, Ton; Kan, Cornelis C.; Buitelaar, Jan K.

    2014-01-01

    This study investigated processing of emotion words in autism spectrum disorders (ASD) using reaction times and event-related potentials (ERP). Adults with (n = 21) and without (n = 20) ASD performed a lexical decision task on emotion and neutral words while their brain activity was recorded. Both groups showed faster responses to emotion words…

  19. Back to the future: brake reaction times for manual and automated vehicles.

    Science.gov (United States)

    Young, Mark S; Stanton, Neville A

    2007-01-15

    Rear-end collisions are often quoted as being a major cause of road traffic accidents. In response to this, a great deal of ergonomics research effort has been directed towards the analysis of brake reaction times. However, the engineering solution has been to develop advanced systems for longitudinal control, which, it is argued, will mitigate the problem of rear-end collisions. So far, though, there have been few empirical studies to determine how brake reaction times will be affected by such vehicle automation. This paper presents a literature review summarizing the current state of knowledge about driver responses in non-automated vehicles. The review covers driver factors, vehicle factors and situational factors. Following the review, some empirical data are presented from a driving simulator experiment assessing brake reaction times of skilled and unskilled drivers under two different levels of automation. When compared to previous data gathered during manual driving, there seems to be a striking increase in reaction times for these automated conditions. Implications for the design and safety of automated vehicle systems are discussed.

  20. Cognitive performance and BMI in childhood: Shared genetic influences between reaction time but not response inhibition

    Science.gov (United States)

    The aim of this work is to understand whether shared genetic influences can explain the associationbetween obesity and cognitive performance, including slower and more variable reaction times(RTs) and worse response inhibition. RT on a four-choice RT task and the go/no-go task, and commission errors...

  1. The Importance of Reaction Times for Developmental Science: What a Difference Milliseconds Make

    Science.gov (United States)

    Lange-Küttner, Christiane

    2012-01-01

    Reaction times are still rarely reported in developmental psychology although they are an indicator of the neural maturity of children's information processing system. Competence and capacity are confounded in development, where children may be able to reason, or remember, but are unable to cope with information processing load. Furthermore, there…

  2. Reaction Time in Grade 5: Data Collection within the Practice of Statistics

    Science.gov (United States)

    Watson, Jane; English, Lyn

    2017-01-01

    This study reports on a classroom activity for Grade 5 students investigating their reaction times. The investigation was part of a 3-year research project introducing students to informal inference and giving them experience carrying out the practice of statistics. For this activity the focus within the practice of statistics was on introducing…

  3. The Effect of Intervention on Accuracy of Students' Responses and Reaction Times to Geometry Problems

    Science.gov (United States)

    Babai, Reuven; Zilber, Hanna; Stavy, Ruth; Tirosh, Dina

    2010-01-01

    This study investigates the effect on student performance in drawing their attention to relevant task variables, focusing on accuracy of responses and reaction times. We chose this methodology in order to better understand how such interventions affect the reasoning process. The study employs a geometry task in which the irrelevant salient…

  4. The Effect of Feedback Schedule Manipulation on Speech Priming Patterns and Reaction Time

    Science.gov (United States)

    Slocomb, Dana; Spencer, Kristie A.

    2009-01-01

    Speech priming tasks are frequently used to delineate stages in the speech process such as lexical retrieval and motor programming. These tasks, often measured in reaction time (RT), require fast and accurate responses, reflecting maximized participant performance, to result in robust priming effects. Encouraging speed and accuracy in responding…

  5. Naturally Biased? In Search for Reaction Time Evidence for a Natural Number Bias in Adults

    Science.gov (United States)

    Vamvakoussi, Xenia; Van Dooren, Wim; Verschaffel, Lieven

    2012-01-01

    A major source of errors in rational number tasks is the inappropriate application of natural number rules. We hypothesized that this is an instance of intuitive reasoning and thus can persist in adults, even when they respond correctly. This was tested by means of a reaction time method, relying on a dual process perspective that differentiates…

  6. Intraindividual Stepping Reaction Time Variability Predicts Falls in Older Adults With Mild Cognitive Impairment.

    Science.gov (United States)

    Bunce, David; Haynes, Becky I; Lord, Stephen R; Gschwind, Yves J; Kochan, Nicole A; Reppermund, Simone; Brodaty, Henry; Sachdev, Perminder S; Delbaere, Kim

    2017-06-01

    Reaction time measures have considerable potential to aid neuropsychological assessment in a variety of health care settings. One such measure, the intraindividual reaction time variability (IIV), is of particular interest as it is thought to reflect neurobiological disturbance. IIV is associated with a variety of age-related neurological disorders, as well as gait impairment and future falls in older adults. However, although persons diagnosed with Mild Cognitive Impairment (MCI) are at high risk of falling, the association between IIV and prospective falls is unknown. We conducted a longitudinal cohort study in cognitively intact (n = 271) and MCI (n = 154) community-dwelling adults aged 70-90 years. IIV was assessed through a variety of measures including simple and choice hand reaction time and choice stepping reaction time tasks (CSRT), the latter administered as a single task and also with a secondary working memory task. Logistic regression did not show an association between IIV on the hand-held tasks and falls. Greater IIV in both CSRT tasks, however, did significantly increase the risk of future falls. This effect was specific to the MCI group, with a stronger effect in persons exhibiting gait, posture, or physiological impairment. The findings suggest that increased stepping IIV may indicate compromised neural circuitry involved in executive function, gait, and posture in persons with MCI increasing their risk of falling. IIV measures have potential to assess neurobiological disturbance underlying physical and cognitive dysfunction in old age, and aid fall risk assessment and routine care in community and health care settings.

  7. Sentence Processing in High Proficient Kannada--English Bilinguals: A Reaction Time Study

    Science.gov (United States)

    Ravi, Sunil Kumar; Chengappa, Shyamala K.

    2015-01-01

    The present study aimed at exploring the semantic and syntactic processing differences between native and second languages in 20 early high proficient Kannada--English bilingual adults through accuracy and reaction time (RT) measurements. Subjects participated in a semantic judgement task (using 50 semantically correct and 50 semantically…

  8. Physical attraction to reliable, low variability nervous systems: Reaction time variability predicts attractiveness.

    Science.gov (United States)

    Butler, Emily E; Saville, Christopher W N; Ward, Robert; Ramsey, Richard

    2017-01-01

    The human face cues a range of important fitness information, which guides mate selection towards desirable others. Given humans' high investment in the central nervous system (CNS), cues to CNS function should be especially important in social selection. We tested if facial attractiveness preferences are sensitive to the reliability of human nervous system function. Several decades of research suggest an operational measure for CNS reliability is reaction time variability, which is measured by standard deviation of reaction times across trials. Across two experiments, we show that low reaction time variability is associated with facial attractiveness. Moreover, variability in performance made a unique contribution to attractiveness judgements above and beyond both physical health and sex-typicality judgements, which have previously been associated with perceptions of attractiveness. In a third experiment, we empirically estimated the distribution of attractiveness preferences expected by chance and show that the size and direction of our results in Experiments 1 and 2 are statistically unlikely without reference to reaction time variability. We conclude that an operating characteristic of the human nervous system, reliability of information processing, is signalled to others through facial appearance. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. More Symmetrical Children Have Faster and More Consistent Choice Reaction Times

    Science.gov (United States)

    Hope, David; Bates, Timothy C.; Dykiert, Dominika; Der, Geoff; Deary, Ian J.

    2015-01-01

    Greater cognitive ability in childhood is associated with increased longevity, and speedier reaction time (RT) might account for much of this linkage. Greater bodily symmetry is linked to both higher cognitive test scores and faster RTs. It is possible, then, that differences in bodily system integrity indexed by symmetry may underlie the…

  10. Reaction Time and Mortality from the Major Causes of Death: The NHANES-III Study

    Science.gov (United States)

    Hagger-Johnson, Gareth; Deary, Ian J.; Davies, Carolyn A.; Weiss, Alexander; Batty, G. David

    2014-01-01

    Objective Studies examining the relation of information processing speed, as measured by reaction time, with mortality are scarce. We explored these associations in a representative sample of the US population. Methods Participants were 5,134 adults (2,342 men) aged 20–59 years from the Third National Health and Nutrition Examination Survey (NHANES III, 1988–94). Results Adjusted for age, sex, and ethnic minority status, a 1 SD slower reaction time was associated with a raised risk of mortality from all-causes (HR = 1.25, 95% CI 1.12, 1.39) and cardiovascular disease (CVD) (HR = 1.36, 95% CI 1.17, 1.58). Having 1 SD more variable reaction time was also associated with greater risk of all-cause (HR = 1.36, 95% CI 1.19, 1.55) and CVD (HR = 1.50, 95% CI 1.33, 1.70) mortality. No associations were observed for cancer mortality. The magnitude of the relationships was comparable in size to established risk factors in this dataset, such as smoking. Interpretation Alongside better-established risk factors, reaction time is associated with increased risk of premature death and cardiovascular disease. It is a candidate risk factor for all-cause and cause-specific mortality. PMID:24489645

  11. Influence of Rotating Shift Work on Visual Reaction Time and Visual Evoked Potential

    OpenAIRE

    R.V., Hemamalini; N, Krishnamurthy; A, Saravanan

    2014-01-01

    Background: The present day life style is changing the circadian rhythm of the body especially in rotating night shift workers. The impact of this prolongs their reaction time. Night shift also interferes with the circadian variation of pupil size which may affect the visual evoked potential.

  12. Reaction time, processing speed and sustained attention in schizophrenia: impact on social functioning.

    Science.gov (United States)

    Lahera, Guillermo; Ruiz, Alicia; Brañas, Antía; Vicens, María; Orozco, Arantxa

    Previous studies have linked processing speed with social cognition and functioning of patients with schizophrenia. A discriminant analysis is needed to determine the different components of this neuropsychological construct. This paper analyzes the impact of processing speed, reaction time and sustained attention on social functioning. 98 outpatients between 18 and 65 with DSM-5 diagnosis of schizophrenia, with a period of 3 months of clinical stability, were recruited. Sociodemographic and clinical data were collected, and the following variables were measured: processing speed (Trail Making Test [TMT], symbol coding [BACS], verbal fluency), simple and elective reaction time, sustained attention, recognition of facial emotions and global functioning. Processing speed (measured only through the BACS), sustained attention (CPT) and elective reaction time (but not simple) were associated with functioning. Recognizing facial emotions (FEIT) correlated significantly with scores on measures of processing speed (BACS, Animals, TMT), sustained attention (CPT) and reaction time. The linear regression model showed a significant relationship between functioning, emotion recognition (P=.015) and processing speed (P=.029). A deficit in processing speed and facial emotion recognition are associated with worse global functioning in patients with schizophrenia. Copyright © 2017 SEP y SEPB. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Effect of reaction time on formation of silica core/shell particles

    Directory of Open Access Journals (Sweden)

    Milan P. Nikolić

    2015-12-01

    Full Text Available The silica core/shell nanostructures were prepared by a wet-chemical process. Silica core particles were prepared by hydrolysis and condensation of tetraethylorthosilicate. The obtained particles (average size ∼0.4 µm were used as templates for assembling of silica nanoparticles generated from highly basic sodium silicate solution. The silica core particles were functionalized with 3-aminopropyltriethoxysilane (APTES to allow electrostatic assembling of silica nanoparticles on the surface of silica core particles. In order to find the optimal conditions for synthesis of silica core/shell particles with mesoporous shells, the effect of reaction time on formation of silica nanoparticles was investigated. The effect of process parameters on generation and aggregation of silica nanoparticles prepared from highly basic sodium silicate solution was also investigated. It was shown that the size of silica nanoparticles and tendency towards aggregation increase with increasing the reaction time and temperature. These behaviours were reflected on the formation of mesoporous silica shell around silica core particles. Thin and uniform mesoporous silica layers were obtained if reaction times were kept short. When the reaction time was prolonged, the thicker and non-uniform shells were obtained.

  14. Reference data on reaction time and aging using the Nintendo Wii Balance Board

    DEFF Research Database (Denmark)

    Blomkvist, Andreas W.; Eika, Fredrik; Rahbek, Martin T.

    2017-01-01

    Background Falls among older adults is one of the major public health challenges facing the rapidly changing demography. The valid assessment of reaction time (RT) and other well-documented risk factors for falls are mainly restricted to specialized clinics due to the equipment needed. The Nintendo...

  15. Agreement and Null Subjects in German L2 Development: New Evidence from Reaction-Time Experiments.

    Science.gov (United States)

    Clahsen, Harald; Hong, Upyong

    1995-01-01

    Reports on reaction time experiments investigating subject-verb agreement and null subjects in 33 Korean learners of German and a control group of 20 German native speakers. Results found that the two phenomena do not covary in the Korean learners, indicating that properties of agreement and null subjects are acquired separately from one another.…

  16. A new Sumudu transform iterative method for time-fractional Cauchy reaction-diffusion equation.

    Science.gov (United States)

    Wang, Kangle; Liu, Sanyang

    2016-01-01

    In this paper, a new Sumudu transform iterative method is established and successfully applied to find the approximate analytical solutions for time-fractional Cauchy reaction-diffusion equations. The approach is easy to implement and understand. The numerical results show that the proposed method is very simple and efficient.

  17. Increased reaction times and reduced response preparation already starts at middle age

    NARCIS (Netherlands)

    Wolkorte, Ria; Kamphuis, Janine; Zijdewind, Inge

    2014-01-01

    Generalized slowing characterizes aging and there is some evidence to suggest that this slowing already starts at midlife. This study aims to assess reaction time changes while performing a concurrent low-force and high-force motor task in young and middle-aged subjects. The high-force motor task is

  18. Cerebral activation related to implicit sequence learning in a Double Serial Reaction Time task

    NARCIS (Netherlands)

    van der Graaf, FHCE; Maguire, RP; Leenders, KL; de Jong, BM

    2006-01-01

    Using functional magnetic resonance imaging (fMRI), we examined the distribution of cerebral activations related to implicitly learning a series of fixed stimulus-response combinations. In a novel - bimanual - variant of the Serial Reaction Time task (SRT), simultaneous finger movements of the two

  19. Processing of Emotion Words by Patients with Autism Spectrum Disorders: Evidence from Reaction Times and EEG

    NARCIS (Netherlands)

    Lartseva, A.V.; Dijkstra, A.F.J.; Kan, C.C.; Buitelaar, J.K.

    2014-01-01

    This study investigated processing of emotion words in autism spectrum disorders (ASD) using reaction times and event-related potentials (ERP). Adults with (n = 21) and without (n = 20) ASD performed a lexical decision task on emotion and neutral words while their brain activity was recorded. Both

  20. Processing of emotion words by patients with autism spectrum disorders: evidence from reaction times and EEG

    NARCIS (Netherlands)

    Lartseva, A.; Dijkstra, T.; Kan, C.C.; Buitelaar, J.K.

    2014-01-01

    This study investigated processing of emotion words in autism spectrum disorders (ASD) using reaction times and event-related potentials (ERP). Adults with (n = 21) and without (n = 20) ASD performed a lexical decision task on emotion and neutral words while their brain activity was recorded. Both

  1. Effects of visual-field and matching instruction on event-related potentials and reaction time.

    NARCIS (Netherlands)

    Kok, A.; van de Vijver, R.; Bouma, A.

    1985-01-01

    Vertical letter pairs were presented randomly in the left and right visual hemifields of 20 right-handed male undergraduates in physical-identity match and name-identity match conditions. Reaction times (RTs) showed a right visual-field superiority for name matches and a left visual-field

  2. Effect of intermittent exercise on multiple-choice reaction times of soccer players

    NARCIS (Netherlands)

    Lemmink, K.A.P.M.; Visscher, C.

    The influence of intermittent exercise on a choice-response time task was investigated. Two groups of 8 male soccer players (M age 20.9, SD=2.0) participated. They spent 4.4 (SD= 1.3) weekly hours on soccer training and had been playing soccer for 13 (SD=3.3) years. Multiple-choice reaction speed

  3. Core Muscle Response Times and Postural Reactions in Soccer Players and Nonplayers

    NARCIS (Netherlands)

    Borghuis, Arend Jan; Lemmink, Koen A. P. M.; Hof, At L.

    BORGHUIS, A. J., K. A. P. M. LEMMINK, and A. L. HOF. Core Muscle Response Times and Postural Reactions in Soccer Players and Nonplayers. Med. Sci. Sports Exerc., Vol. 43, No. 1, pp. 108-114, 2011. Decreased core stability has been suggested to be associated with a higher occurrence of lower

  4. Auditory event-related potentials and reaction time during decompression from hyperbaric trimix conditions.

    Science.gov (United States)

    Philipova, D

    1998-06-01

    Auditory event-related potentials (ERP) and sensomotor reaction time (RT) were investigated in divers during decompression from hyperbaric trimix conditions in order to assess the auditory information processing of the divers. Two passive series, 30 low (800 Hz) and 30 high (1200 Hz) tones were presented as well as one simple reaction task (SRT) and one choice reaction task (CRT) series. In both task series, the subjects were instructed to press the button as quickly as possible with the right-hand thumb after a low tone was heard. The individual analyses of the decompression period ERPs and RT data were compared with the pre-diving results for the series. Despite the interindividual differences, the sensomotor reactions were retarded during the decompression period, most clearly in the CRT. A prolongation of the N2 and P3 latency in this series gives grounds to accept that a cognitive slowing takes part in the longer reaction times during decompression. The slowing of the auditory information processing during decompression manifests with task manipulation difficulties.

  5. Contaminant transport in soil with depth-dependent reaction coefficients and time-dependent boundary conditions.

    Science.gov (United States)

    Gao, Guangyao; Fu, Bojie; Zhan, Hongbin; Ma, Ying

    2013-05-01

    Predicting the fate and movement of contaminant in soils and groundwater is essential to assess and reduce the risk of soil contamination and groundwater pollution. Reaction processes of contaminant often decreased monotonously with depth. Time-dependent input sources usually occurred at the inlet of natural or human-made system such as radioactive waste disposal site. This study presented a one-dimensional convection-dispersion equation (CDE) for contaminant transport in soils with depth-dependent reaction coefficients and time-dependent inlet boundary conditions, and derived its analytical solution. The adsorption coefficient and degradation rate were represented as sigmoidal functions of soil depth. Solute breakthrough curves (BTCs) and concentration profiles obtained from CDE with depth-dependent and constant reaction coefficients were compared, and a constant effective reaction coefficient, which was calculated by arithmetically averaging the depth-dependent reaction coefficient, was proposed to reflect the lumped depth-dependent reaction effect. With the effective adsorption coefficient and degradation rate, CDE could produce similar BTCs and concentration profiles as those from CDE with depth-dependent reactions in soils with moderate chemical heterogeneity. In contrast, the predicted concentrations of CDE with fitted reaction coefficients at a certain depth departed significantly from those of CDE with depth-dependent reactions. Parametric analysis was performed to illustrate the effects of sinusoidally and exponentially decaying input functions on solute BTCs. The BTCs and concentration profiles obtained from the solutions for finite and semi-infinite domain were compared to investigate the effects of effluent boundary condition. The finite solution produced higher concentrations at the increasing limb of the BTCs and possessed a higher peak concentration than the semi-infinite solution which had a slightly long tail. Furthermore, the finite solution gave

  6. The influenced of reaction time on the degradation of palm oil empty fruit bunch (EFB) in hydrothermal carbonization

    Science.gov (United States)

    Sarwono, Rakhman; Kurniawan, Hendris Hendarsyah

    2017-11-01

    Hydrothermal carbonization (HTC) of empty fruit bunch (EFB) of palm oil in different reaction times were investigated. Experiments were carried out in an autoclave at different reaction time of 3,6,9, 15, 20, 25 and 40 hours. With a fixed solid/liquid ratio of 5 gram of EFB in 50 ml water as a solvent, and temperature reaction of 250 °C. Increase the reaction time the soluble products are also increased. The liquid products were analyzed using GCMS to determine the chemical composition. The chemical composition were greatly affected by the reaction time. The main component was glycolic acid, by increasing the reaction time made the varieties of chemical compositions in liquid products, especially for the glycolic acid component, it was decreased slightly. The higher heating value (HHV) also increase slighly by increasing the reaction time both solid and liquid products.

  7. Mix and Inject: Reaction Initiation by Diffusion for Time-Resolved Macromolecular Crystallography

    Directory of Open Access Journals (Sweden)

    Marius Schmidt

    2013-01-01

    Full Text Available Time-resolved macromolecular crystallography unifies structure determination with chemical kinetics, since the structures of transient states and chemical and kinetic mechanisms can be determined simultaneously from the same data. To start a reaction in an enzyme, typically, an initially inactive substrate present in the crystal is activated. This has particular disadvantages that are circumvented when active substrate is directly provided by diffusion. However, then it is prohibitive to use macroscopic crystals because diffusion times become too long. With small micro- and nanocrystals diffusion times are adequately short for most enzymes and the reaction can be swiftly initiated. We demonstrate here that a time-resolved crystallographic experiment becomes feasible by mixing substrate with enzyme nanocrystals which are subsequently injected into the X-ray beam of a pulsed X-ray source.

  8. A novel approach to sports concussion assessment: Computerized multilimb reaction times and balance control testing.

    Science.gov (United States)

    Vartiainen, Matti V; Holm, Anu; Lukander, Jani; Lukander, Kristian; Koskinen, Sanna; Bornstein, Robert; Hokkanen, Laura

    2016-01-01

    Mild traumatic brain injuries (MTBI) or concussions often result in problems with attention, executive functions, and motor control. For better identification of these diverse problems, novel approaches integrating tests of cognitive and motor functioning are needed. The aim was to characterize minor changes in motor and cognitive performance after sports-related concussions with a novel test battery, including balance tests and a computerized multilimb reaction time test. The cognitive demands of the battery gradually increase from a simple stimulus response to a complex task requiring executive attention. A total of 113 male ice hockey players (mean age = 24.6 years, SD = 5.7) were assessed before a season. During the season, nine concussed players were retested within 36 hours, four to six days after the concussion, and after the season. A control group of seven nonconcussed players from the same pool of players with comparable demographics were retested after the season. Performance was measured using a balance test and the Motor Cognitive Test battery (MotCoTe) with multilimb responses in simple reaction, choice reaction, inhibition, and conflict resolution conditions. The performance of the concussed group declined at the postconcussion assessment compared to both the baseline measurement and the nonconcussed controls. Significant changes were observed in the concussed group for the multilimb choice reaction and inhibition tests. Tapping and balance showed a similar trend, but no statistically significant difference in performance. In sports-related concussions, complex motor tests can be valuable additions in assessing the outcome and recovery. In the current study, using subtasks with varying cognitive demands, it was shown that while simple motor performance was largely unaffected, the more complex tasks induced impaired reaction times for the concussed subjects. The increased reaction times may reflect the disruption of complex and integrative cognitive

  9. Alterations of Visual Reaction Time and Short Term Memory in Military Radar Personnel

    Science.gov (United States)

    MORTAZAVI, Seyed Mohammad Javad; TAEB, Shahram; DEHGHAN, Naser

    2013-01-01

    Background Radar transmitters emit high-power radiofrequency radiation by creation of a high-voltage and high-frequency alternating electrical current. Methods: Health effects of occupational exposure to military radar were investigated. Visual reaction time was recorded with a simple blind computer-assisted-visual reaction time test. To assess the short-term memory, modified Wechsler Memory Scale test was performed. Results: The mean +/- SD reaction time in radar works (N=100) and the control group (N=57) were 238.58 +/− 23.47 milliseconds and 291.86 +/− 28.26 milliseconds (P<0.0001), respectively. The scores of forward digit span in radar works and the control group were 3.56 +/− 0.77 and 4.29 +/− 1.06 (P<0.0001), while the scores of backward digit span in radar works and the control group were 2.70 +/− 0.69 and 3.62 +/− 0.95 (P<0.0001). The scores of word recognition in radar works and the control group were 3.37 +/− 1.13 and 5.86 +/− 1.11 (P<0.0001). Finally, the scores of paired words in radar works and the control group were 13.56 +/− 1.78 and 15.21 +/− 2.20 (P<0.0001). It can be concluded that occupational exposures to radar radiations decreases reaction time, which may lead to a better response to different hazards. Conclusion: To the best of our knowledge, this is the first study to show that occupational exposure to radar microwave radiation leads to decreased reaction time and the lower performance of short-term memory. Altogether, these results indicate that occupational exposure to radar microwave radiations may be linked to some non-detrimental and detrimental health effects. PMID:23785684

  10. Cognitive decline and slower reaction time in elderly individuals with mild cognitive impairment.

    Science.gov (United States)

    Chen, Ko-Chia; Weng, Chia-Ying; Hsiao, Sigmund; Tsao, Wen-Long; Koo, Malcolm

    2017-11-01

    The relationship between declining performance, as measured by changes in reaction time, and declining cognitive function has not been critically studied. The aim of the present study was to investigate the association between reaction time during a task and cognitive ability in elderly Taiwanese individuals. Patients aged 65 years or older with mild cognitive impairment (MCI) (n = 33) and Alzheimer's disease (n = 26) were recruited from the neurology clinic of a regional hospital in southern Taiwan. In addition, 28 healthy controls aged 65 years or older were recruited from the community. The cognitive performance of the study participants was assessed using the Cognitive Abilities Screening Instrument (CASI). A computer-administered simple reaction time (SRT) task and a flanker reaction time (FRT) task were administered to assess participants' cognitive function. A non-parametric Kruskal-Wallis test was performed to compare CASI scores, SRT, and FRT among the three groups. anova was also used to compare CASI scores, inverse-transformed SRT, and inverse-transformed FRT among the three groups, with adjustment for age and years of education. Additionally, Pearson's partial correlation coefficients were used to assess the association of CASI scores with inverse-transformed SRT, and inverse-transformed FRT within each of the three groups. Significant differences in CASI scores, SRT, and FRT were found between the Alzheimer's disease group and the other two groups, either with or without adjustment for age or education. The reaction time of patients with Alzheimer's disease was significantly slower than the other two groups. Moreover, significant correlation between CASI and FRT was found in patients with MCI. Altered performance in a speed task was observed in patients with MCI. The FRT task should further be explored for its role as a marker for cognitive decline in elderly individuals, particularly in those with MCI. © 2017 Japanese Psychogeriatric

  11. THE INFLUENCE OF BALL VELOCITY AND COURT ILLUMINATION ON REACTION TIME FOR TENNIS VOLLEY

    Directory of Open Access Journals (Sweden)

    Jui-hung Tu

    2010-03-01

    Full Text Available The he purpose of this study is to examine the effects of ball velocity, court illumination, and volley type on the reaction time (RT of a tennis athlete for a volley stroke. Eights cases with two different ball velocities (high and low, two volley types (forehand and backhand and two court illumination levels (dark and bright were studied. The 30 participating subjects consisted of 18 male and 12 female college tennis athletes (age: 24 ± 3.2 yr, with a United States Tennis Association (USTA ranking above 2.5. In order to ensure the validity of real-world correlations, the experiments were designed to simulate real competition situations. Reaction times were measured for volley strokes in response to different approaching ball velocities (high: 25.05 ± 0.37 m/s and low: 17.56 ± 0.92 m·s-1 for several volley types (forehand and backhand and court illumination levels (55649 ± 4292 lux and 363.24 ± 6.53 lux on the court. During the tests, the signals from an electromyogram sensor and a 3-axis accelerometer (± 50 g were recorded using an NI DAQ card (NI PXI-6251 and then analyzed to determine reaction time (RT, premotor reaction time (PRT, and motor reaction time (MRT through the LabVIEW system. Subsequent 3-way ANOVA analysis indicated no RT, PRT, or MRT interaction between ball velocity, volley type and illumination. The ball velocity and illumination parameters did affect RT and PRT values significantly with p < 0.05, no significant variation in MRT was observed across any implemented experimental conditions. All experimental results indicate that ball velocity and illumination levels strongly affect the value of PRT, but have no significant effect on the value of MRT, the changes in RT were dominated by PRT

  12. Multi-scale approach for simulating time-delay biochemical reaction systems.

    Science.gov (United States)

    Niu, Yuanling; Burrage, Kevin; Zhang, Chengjian

    2015-02-01

    This study presents a multi-scale approach for simulating time-delay biochemical reaction systems when there are wide ranges of molecular numbers. The authors construct a new efficient approach based on partitioning into slow and fast subsets in conjunction with predictor-corrector methods. This multi-scale approach is shown to be much more efficient than existing methods such as the delay stochastic simulation algorithm and the modified next reaction method. Numerical testing on several important problems in systems biology confirms the accuracy and computational efficiency of this approach.

  13. Fixating at far distance shortens reaction time to peripheral visual stimuli at specific locations.

    Science.gov (United States)

    Kokubu, Masahiro; Ando, Soichi; Oda, Shingo

    2017-11-07

    The purpose of the present study was to examine whether the fixation distance in real three-dimensional space affects manual reaction time to peripheral visual stimuli. Light-emitting diodes were used for presenting a fixation point and four peripheral visual stimuli. The visual stimuli were located at a distance of 45cm and at 25° in the left, right, upper, and lower directions from the sagittal axis including the fixation point. Near (30cm), Middle (45cm), Far (90cm), and Very Far (300cm) fixation distance conditions were used. When one of the four visual stimuli was randomly illuminated, the participants released a button as quickly as possible. Results showed that overall peripheral reaction time decreased as the fixation distance increased. The significant interaction between fixation distance and stimulus location indicated that the effect of fixation distance on reaction time was observed at the left, right, and upper locations but not at the lower location. These results suggest that fixating at far distance would contribute to faster reaction and that the effect is specific to locations in the peripheral visual field. The present findings are discussed in terms of viewer-centered representation, the focus of attention in depth, and visual field asymmetry related to neurological and psychological aspects. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A constant-time kinetic Monte Carlo algorithm for simulation of large biochemical reaction networks

    Science.gov (United States)

    Slepoy, Alexander; Thompson, Aidan P.; Plimpton, Steven J.

    2008-05-01

    The time evolution of species concentrations in biochemical reaction networks is often modeled using the stochastic simulation algorithm (SSA) [Gillespie, J. Phys. Chem. 81, 2340 (1977)]. The computational cost of the original SSA scaled linearly with the number of reactions in the network. Gibson and Bruck developed a logarithmic scaling version of the SSA which uses a priority queue or binary tree for more efficient reaction selection [Gibson and Bruck, J. Phys. Chem. A 104, 1876 (2000)]. More generally, this problem is one of dynamic discrete random variate generation which finds many uses in kinetic Monte Carlo and discrete event simulation. We present here a constant-time algorithm, whose cost is independent of the number of reactions, enabled by a slightly more complex underlying data structure. While applicable to kinetic Monte Carlo simulations in general, we describe the algorithm in the context of biochemical simulations and demonstrate its competitive performance on small- and medium-size networks, as well as its superior constant-time performance on very large networks, which are becoming necessary to represent the increasing complexity of biochemical data for pathways that mediate cell function.

  15. Chemical dynamics in the gas phase: Time-dependent quantum mechanics of chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Gray, S.K. [Argonne National Laboratory, IL (United States)

    1993-12-01

    A major goal of this research is to obtain an understanding of the molecular reaction dynamics of three and four atom chemical reactions using numerically accurate quantum dynamics. This work involves: (i) the development and/or improvement of accurate quantum mechanical methods for the calculation and analysis of the properties of chemical reactions (e.g., rate constants and product distributions), and (ii) the determination of accurate dynamical results for selected chemical systems, which allow one to compare directly with experiment, determine the reliability of the underlying potential energy surfaces, and test the validity of approximate theories. This research emphasizes the use of recently developed time-dependent quantum mechanical methods, i.e. wave packet methods.

  16. Reactions of 1-Hydroxy-1-methylethyl Radicals with NO2-: Time-Resolved Electron Spin Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Filipiak, Piotr; Camaioni, Donald M.; Fessenden, Richard W.; Carmichael, Ian; Hug, Gordon L.

    2006-09-11

    The reaction of the ?-hydroxyalkyl radical of 2-propanol (1-hydroxy-1-methylethyl radical) with nitrite ions was characterized. A product of the reaction was assigned as the adduct nitro radical anion, [HO-C(CH3)2NO2]??. This radical was identified using time-resolved electron spin resonance (TRESR). The radical?s magnetic parameters, the nitrogen hyperfine coupling constant aN of 26.39 G and its g-factor of 2.0052, are the same as those of the nitro radical anion previously discovered in ?OH spin-trapping experiments with the aci-anion of (CH3)2CHNO2. The rate constant for the decay of the ESR kinetic trace of (CH3)2C?-OH is of the same order of magnitude as the rate constant for the growth of the ESR kinetic trace of [HO-C(CH3)2NO2]??, further confirming the nature of the reaction. The bimolecular rate constant for the reaction at pH 7 is {approx}1.7 ? 106 M?1 s?1 measured by following ESR kinetic traces of (CH3)2C?-OH and 2.4 ? 106 M?1 s?1 following the growth of [HO-C(CH3)2NO2]??. The lack of better match in these two measurements is discussed. The yield of [HO-C(CH3)2NO2]?? was measured to be {approx}27% of the reaction of (CH3)2C?-OH with nitrite. Pulse radiolysis-conductivity experiments at lower pH (4.7) also show that electron transfer or the equivalent formation of [HO-C(CH3)2ONO]?? followed by rapid loss of ?NO represent only part of the reaction. These reactions are discussed with guidance by computations using density functional theory.

  17. Analysis of Thermal and Reaction Times for Hydrogen Reduction of Lunar Regolith

    Science.gov (United States)

    Hegde, U.; Balasubramaniam, R.; Gokoglu, S.

    2009-01-01

    System analysis of oxygen production by hydrogen reduction of lunar regolith has shown the importance of the relative time scales for regolith heating and chemical reaction to overall performance. These values determine the sizing and power requirements of the system and also impact the number and operational phasing of reaction chambers. In this paper, a Nusselt number correlation analysis is performed to determine the heat transfer rates and regolith heat up times in a fluidized bed reactor heated by a central heating element (e.g., a resistively heated rod, or a solar concentrator heat pipe). A coupled chemical and transport model has also been developed for the chemical reduction of regolith by a continuous flow of hydrogen. The regolith conversion occurs on the surfaces of and within the regolith particles. Several important quantities are identified as a result of the above analyses. Reactor scale parameters include the void fraction (i.e., the fraction of the reactor volume not occupied by the regolith particles) and the residence time of hydrogen in the reactor. Particle scale quantities include the particle Reynolds number, the Archimedes number, and the time needed for hydrogen to diffuse into the pores of the regolith particles. The analysis is used to determine the heat up and reaction times and its application to NASA s oxygen production system modeling tool is noted.

  18. Effects of aging on temporal predictive mechanisms of speech and hand motor reaction time.

    Science.gov (United States)

    Johari, Karim; den Ouden, Dirk-Bart; Behroozmand, Roozbeh

    2018-02-01

    Evidence from previous studies has suggested that movement execution in younger adults is accelerated in response to temporally predictable vs. unpredictable sensory stimuli. This effect indicates that external temporal information can modulate motor behavior; however, how aging can influence temporal predictive mechanisms in motor system has yet to be understood. The objective of the present study was to investigate aging effects on the initiation and inhibition of speech and hand movement reaction times in response to temporally predictable and unpredictable sensory stimuli. Fifteen younger (mean age 22.6) and fifteen older (mean age 63.8) adults performed a randomized speech vowel vocalization or button press initiation and inhibition tasks in two counterbalanced blocks in response to temporally predictable and unpredictable visual cue stimuli. Results showed that motor reaction time was accelerated in both younger and older adults for predictable vs. unpredictable stimuli during initiation and inhibition of speech and hand movement. However, older adults were significantly slower than younger adults in motor execution of speech and hand movement when stimulus timing was unpredictable. Moreover, we found that overall, motor inhibition of speech and hand was executed faster than their initiation. Our findings suggest that older adults can compensate age-related decline in motor reaction times by incorporating external temporal information and execute faster movement in response to predictable stimuli, whereas unpredictable temporal information cannot counteract aging effects efficiently and lead to less accurate motor timing predictive codes for speech production and hand movement.

  19. The effects of reactants ratios, reaction temperatures and times on Maillard reaction products of the L-ascorbic acid/L-glutamic acid system

    Directory of Open Access Journals (Sweden)

    Yong-Yan ZHOU

    2016-01-01

    Full Text Available Abstract The transformation law of the Maillard reaction products with three different reactants ratios - equimolar reactants, excess L-glutamic acid and excess L-ascorbic acid reaction respectively, five different temperatures, and different time conditions for the L-ascorbic acid / L-glutamic acid system were investigated. Results showed that, the increase of the reaction time and temperature led to the increase of the browning products, uncoloured intermediate products, as well as aroma compounds. Compared with the equimolar reaction system, the excess L-ascorbic acid reaction system produced more browning products and uncoloured intermediate products, while the aroma compounds production remained the same. In the excess L-glutamic acid system, the uncoloured intermediate products increased slightly, the browning products remained the same, while the aroma compounds increased.

  20. Considerations for the independent reaction times and step-by-step methods for radiation chemistry simulations

    Science.gov (United States)

    Plante, Ianik; Devroye, Luc

    2017-10-01

    Ionizing radiation interacts with the water molecules of the tissues mostly by ionizations and excitations, which result in the formation of the radiation track structure and the creation of radiolytic species such as H.,.OH, H2, H2O2, and e-aq. After their creation, these species diffuse and may chemically react with the neighboring species and with the molecules of the medium. Therefore radiation chemistry is of great importance in radiation biology. As the chemical species are not distributed homogeneously, the use of conventional models of homogeneous reactions cannot completely describe the reaction kinetics of the particles. Actually, many simulations of radiation chemistry are done using the Independent Reaction Time (IRT) method, which is a very fast technique to calculate radiochemical yields but which do not calculate the positions of the radiolytic species as a function of time. Step-by-step (SBS) methods, which are able to provide such information, have been used only sparsely because these are time-consuming in terms of calculation. Recent improvements in computer performance now allow the regular use of the SBS method in radiation chemistry. The SBS and IRT methods are both based on the Green's functions of the diffusion equation (GFDE). In this paper, several sampling algorithms of the GFDE and for the IRT method are presented. We show that the IRT and SBS methods are exactly equivalent for 2-particles systems for diffusion and partially diffusion-controlled reactions between non-interacting particles. We also show that the results obtained with the SBS simulation method with periodic boundary conditions are in agreement with the predictions by classical reaction kinetics theory, which is an important step towards using this method for modelling of biochemical networks and metabolic pathways involved in oxidative stress. Finally, the first simulation results obtained with the code RITRACKS (Relativistic Ion Tracks) are presented.

  1. The effect of repetitive ankle perturbations on muscle reaction time and muscle activity.

    Science.gov (United States)

    Thain, Peter Kevin; Hughes, Gerwyn Trefor Gareth; Mitchell, Andrew Charles Stephen

    2016-10-01

    The use of a tilt platform to simulate a lateral ankle sprain and record muscle reaction time is a well-established procedure. However, a potential caveat is that repetitive ankle perturbation may cause a natural attenuation of the reflex latency and amplitude. This is an important area to investigate as many researchers examine the effect of an intervention on muscle reaction time. Muscle reaction time, peak and average amplitude of the peroneus longus and tibialis anterior in response to a simulated lateral ankle sprain (combined inversion and plantar flexion movement) were calculated in twenty-two physically active participants. The 40 perturbations were divided into 4 even groups of 10 dominant limb perturbations. Within-participants repeated measures analysis of variance (ANOVA) tests were conducted to assess the effect of habituation over time for each variable. There was a significant reduction in the peroneus longus average amplitude between the aggregated first and last 10 consecutive ankle perturbations (F2.15,45.09=3.90, P=0.03, ɳp(2)=0.16). Authors should implement no more than a maximum of 30 consecutive ankle perturbations (inclusive of practice perturbations) in future protocols simulating a lateral ankle sprain in an effort to avoid significant attenuation of muscle activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Existence and Stability of Traveling Waves for Degenerate Reaction-Diffusion Equation with Time Delay

    Science.gov (United States)

    Huang, Rui; Jin, Chunhua; Mei, Ming; Yin, Jingxue

    2018-01-01

    This paper deals with the existence and stability of traveling wave solutions for a degenerate reaction-diffusion equation with time delay. The degeneracy of spatial diffusion together with the effect of time delay causes us the essential difficulty for the existence of the traveling waves and their stabilities. In order to treat this case, we first show the existence of smooth- and sharp-type traveling wave solutions in the case of c≥c^* for the degenerate reaction-diffusion equation without delay, where c^*>0 is the critical wave speed of smooth traveling waves. Then, as a small perturbation, we obtain the existence of the smooth non-critical traveling waves for the degenerate diffusion equation with small time delay τ >0 . Furthermore, we prove the global existence and uniqueness of C^{α ,β } -solution to the time-delayed degenerate reaction-diffusion equation via compactness analysis. Finally, by the weighted energy method, we prove that the smooth non-critical traveling wave is globally stable in the weighted L^1 -space. The exponential convergence rate is also derived.

  3. The Effect of Lateral Ankle Ligament Repair in Muscle Reaction Time in Patients with Mechanical Ankle Instability.

    Science.gov (United States)

    Li, H-Y; Zheng, J-J; Zhang, J; Hua, Y-H; Chen, S-Y

    2015-11-01

    Studies have shown that functional ankle instability can result in prolonged muscle reaction time. However, the deficit in muscle reaction time in patients with mechanical ankle instability (MAI) and the effect of lateral ankle ligament repair on muscle reaction time are unclear. The purpose of this study was to identify the deficit in muscle reaction time, and to evaluate the role of lateral ligament repair in improving muscle reaction time in MAI patients. Sixteen MAI patients diagnosed with lateral ankle ligament tears by ultrasonography and magnetic resonance imaging underwent arthroscopic debridement and open lateral ankle ligament repair with a modified Broström procedure. One day before the operation, reaction times of the tibialis anterior and peroneus longus muscles were recorded following sudden inversion perturbation while walking on a custom walkway, and anterior drawer test (ADT) and American Orthopaedic Foot and Ankle Society (AOFAS) scale score were evaluated. Six months postoperatively, muscle reaction time, ADT and AOFAS scale score were reevaluated, and muscle reaction times in 15 healthy controls were also recorded. Preoperatively, the affected ankles in the MAI group had significantly delayed tibialis anterior and peroneus longus muscles reaction times compared with controls. Six months after the operation, median AOFAS scale scores were significantly greater than preoperatively, and ADT was negative in the MAI group. However, the affected ankles in the MAI group showed no difference in muscle reaction time compared with preoperative values. MAI patients had prolonged muscle reaction time. The modified Broström procedure produced satisfactory clinical outcomes in MAI patients, but did not shorten reaction times of the tibialis anterior and peroneus longus muscles. © Georg Thieme Verlag KG Stuttgart · New York.

  4. A time-dependent quantum dynamical study of the H + HBr reaction.

    Science.gov (United States)

    Fu, Bina; Zhang, Dong H

    2007-09-27

    Time-dependent wave packet calculations were carried out to study the exchange and abstraction processes in the title reaction on the Kurosaki-Takayanagi potential energy surface (Kurosaki, Y.; Takayanagi, T. J. Chem. Phys. 2003, 119, 7838). Total reaction probabilities and integral cross sections were calculated for the reactant HBr initially in the ground state, first rotationally excited state, and first vibrationally excited state for both the exchange and abstraction reactions. At low collision energy, only the abstraction reaction occurs because of its low barrier height. Once the collision energy exceeds the barrier height of the exchange reaction, the exchange process quickly becomes the dominant process presumably due to its larger acceptance cone. It is found that initial vibrational excitation of HBr enhances both processes, while initial rotational excitation of HBr from j(0) = 0 to 1 has essentially no effect on both processes. For the abstraction reaction, the theoretical cross section at E(c) = 1.6 eV is 1.06 A(2), which is smaller than the experimental result of 3 +/- 1 A(2) by a factor of 2-3. On the other hand, the theoretical rate constant is larger than the experimental results by about a factor of 2 in the temperature region between 220 and 550 K. It is also found that the present quantum rate constant is larger than the TST result by a factor of 2 at 200 K. However, the agreement between the present quantum rate constant and the TST result improves as the temperature increases.

  5. Reaction Wheel Installation Deviation Compensation for Overactuated Spacecraft with Finite-Time Attitude Control

    Directory of Open Access Journals (Sweden)

    Aihua Zhang

    2013-01-01

    Full Text Available A novel attitude tracking control scheme is presented for overactuated spacecraft to address the attitude stabilization problem in presence of reaction wheel installation deviation, external disturbance and uncertain mass of moment inertia. An adaptive sliding mode control technique is proposed to track the uncertainty. A Lyapunov-based analysis shows that the compensation control law can guarantee that the desired attitude trajectories are followed in finite-time. The key feature of the proposed control strategy is that it globally asymptotically stabilizes the system, even in the presence of reaction wheel installation deviation, external disturbances, and uncertain mass of moment inertia. The attitude track performance using the proposed finite-time compensation control is evaluated through a numerical example.

  6. Binaural Sound Reduces Reaction Time in a Virtual Reality Search Task

    DEFF Research Database (Denmark)

    Høeg, Emil Rosenlund; Gerry, Lynda; Thomsen, Lui Albæk

    2017-01-01

    Salient features in a visual search task can direct attention and increase competency on these tasks. Simple cues, such as color change in a salient feature, called the "pop-out effect" can increase task solving efficiency [6]. Previous work has shown that nonspatial auditory signals temporally...... synched with a pop-out effect can improve reaction time in a visual search task, called the "pip and pop effect" [14]. This paper describes a within-group study on the effect of audiospatial attention in virtual reality given a 360-degree visual search. Three cue conditions were compared (no sound, stereo......, and binaural), with rising degrees of difficulty by increasing the set size. The results (n=10) indicate a statistically significant difference in reaction time between the three conditions. Overall, in spite of the small sample size, our results seem to indicate that binaural audio renders a clear advantage...

  7. Loudness Perception in the Domestic Cat: Reaction Time Estimates of Equal Loudness Contours and Recruitment Effects

    OpenAIRE

    May, Bradford J.; Little, Nicole; Saylor, Stephanie

    2009-01-01

    The domestic cat is the primary physiological model of loudness coding and recruitment. At present, there are no published descriptions of loudness perception in this species. This study used a reaction time task to characterize loudness perception in six behaviorally trained cats. The psychophysical approach was based on the assumption that sounds of equal loudness elicit responses of equal latency. The resulting equal latency contours reproduced well-known features of human equal loudness c...

  8. A Strongly A-Stable Time Integration Method for Solving the Nonlinear Reaction-Diffusion Equation

    OpenAIRE

    Wenyuan Liao

    2014-01-01

    The semidiscrete ordinary differential equation (ODE) system resulting from compact higher-order finite difference spatial discretization of a nonlinear parabolic partial differential equation, for instance, the reaction-diffusion equation, is highly stiff. Therefore numerical time integration methods with stiff stability such as implicit Runge-Kutta methods and implicit multistep methods are required to solve the large-scale stiff ODE system. However those methods are computationally expensi...

  9. Analysis of Reaction Times and Aerobic Capacities of Soccer Players According to Their Playing Positions

    Science.gov (United States)

    Taskin, Cengiz; Karakoc, Onder; Taskin, Mine; Dural, Murat

    2016-01-01

    70 soccer players in Gaziantep amateur league voluntarily participated in this study, (average of their ages 19,17±1,34years, average of their heights 181,28±5,06 cm, average of their body weights 76,75±4,43 kg and average of their sports experiences 3,78±0,95 years) to analyze visual and auditory reaction times and aerobic capacities of amateur…

  10. Decision-Making in Adolescents According to reaction Time, HEG and PASS

    OpenAIRE

    Pérez Álvarez, Frederic; Serra Sala, Mireia; Timoneda Gallart, Carme

    2016-01-01

    Background: The Planning, Attention, Simultaneous and Successive (PASS) theory of intelligence allows us cognitive assessment. Hemoencephalography (HEG) allows us to assess cortical prefrontal activity. Reaction time (RT) allows us to assess decision-making. We aim to find teenager profile according to the PASS, HEG, and RT. Methods and findings: 59 secondary education adolescent students (30 females and 29 males, 14-16- year-old, mean=15.29, SD=0.67) were tested by two RT + HEG expe...

  11. Effects of Mood on Learning in the Serial Reaction Time Task

    OpenAIRE

    Jones, Emma Marie

    2011-01-01

    After a brief overview of existing research on the relationship between mood and implicit learning, some methodological concerns are addressed and an empirical study is reported. Participants (N = 80) were trained on a serial reaction time (SRT) task. Mood was induced by the target stimuli being pictures of human faces expressing happiness (positive mood condition) or sadness (negative mood condition). Response stimulus interval (RSI) was 0 or 500 ms, traditionally associ...

  12. The effects of spinal manipulative therapy on reaction and response time of cricket players

    OpenAIRE

    2010-01-01

    M. Tech. Method The purpose of this study was to determine whether spinal manipulative therapy (SMT) of the cervical spinal segments would have any influence on the reaction and response time of a cricket player. It has been suggested that a dysfunctional vertebral subluxation complex can cause a decrease in visual performance. The decreased visual performance may be due to decreased blood flow to the visual centers of the brain. Thirty six participants (3 cricket teams) participated in th...

  13. Simple reaction time in soccer players from differing categories and field positions

    Directory of Open Access Journals (Sweden)

    C. Ruschel

    2011-01-01

    Full Text Available This study aimed at analyzing the visual and auditory simple reaction times in soccer players from differing categories and field positions. Participated in the study 49 male soccer players, amateurs and professionals, occupying the field positions of goalkeeper, center defender, right and left defender, halfback, midfielder, and forward. Data collection was carried out through a system composed by a switch, a mechanism of visual and auditory stimuli and appropriate acquisition software. Data were analyzed through descriptive and inferential statistics (p < .05. When comparing categories, there was no difference in visual reaction time (VRT. Professionals showed faster auditory reaction times (ART than amateurs did. Regarding field positions, goalkeepers showed significantly faster VRT than midfielders and there was no difference in terms of ART. Main differences between players from differing categories and field positions may be due to the adoption of more complex strategies in retaining and using visual information in specific situations. ART may be less important in soccer, since this is essentially a visual game.

  14. Influence of temperature and reaction time on the conversion of polystyrene waste to pyrolysis liquid oil.

    Science.gov (United States)

    Miandad, R; Nizami, A S; Rehan, M; Barakat, M A; Khan, M I; Mustafa, A; Ismail, I M I; Murphy, J D

    2016-12-01

    This paper aims to investigate the effect of temperature and reaction time on the yield and quality of liquid oil produced from a pyrolysis process. Polystyrene (PS) type plastic waste was used as a feedstock in a small pilot scale batch pyrolysis reactor. At 400°C with a reaction time of 75min, the gas yield was 8% by mass, the char yield was 16% by mass, while the liquid oil yield was 76% by mass. Raising the temperature to 450°C increased the gas production to 13% by mass, reduced the char production to 6.2% and increased the liquid oil yield to 80.8% by mass. The optimum temperature and reaction time was found to be 450°C and 75min. The liquid oil at optimum conditions had a dynamic viscosity of 1.77mPas, kinematic viscosity of 1.92cSt, a density of 0.92g/cm3, a pour point of -60°C, a freezing point of -64°C, a flash point of 30.2°C and a high heating value (HHV) of 41.6MJ/kg this is similar to conventional diesel. The gas chromatography with mass spectrophotometry (GC-MS) analysis showed that liquid oil contains mainly styrene (48%), toluene (26%) and ethyl-benzene (21%) compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Relationships Between Countermovement Jump Ground Reaction Forces and Jump Height, Reactive Strength Index, and Jump Time.

    Science.gov (United States)

    Barker, Leland A; Harry, John R; Mercer, John A

    2018-01-01

    Barker, LA, Harry, JR, and Mercer, JA. Relationships between countermovement jump ground reaction forces and jump height, reactive strength index, and jump time. J Strength Cond Res 32(1): 248-254, 2018-The purpose of this study was to determine the relationship between ground reaction force (GRF) variables to jump height, jump time, and the reactive strength index (RSI). Twenty-six, Division-I, male, soccer players performed 3 maximum effort countermovement jumps (CMJs) on a dual-force platform system that measured 3-dimensional kinetic data. The trial producing peak jump height was used for analysis. Vertical GRF (Fz) variables were divided into unloading, eccentric, amortization, and concentric phases and correlated with jump height, RSI (RSI = jump height/jump time), and jump time (from start to takeoff). Significant correlations were observed between jump height and RSI, concentric kinetic energy, peak power, concentric work, and concentric displacement. Significant correlations were observed between RSI and jump time, peak power, unload Fz, eccentric work, eccentric rate of force development (RFD), amortization Fz, amortization time, second Fz peak, average concentric Fz, and concentric displacement. Significant correlations were observed between jump time and unload Fz, eccentric work, eccentric RFD, amortization Fz, amortization time, average concentric Fz, and concentric work. In conclusion, jump height correlated with variables derived from the concentric phase only (work, power, and displacement), whereas Fz variables from the unloading, eccentric, amortization, and concentric phases correlated highly with RSI and jump time. These observations demonstrate the importance of countermovement Fz characteristics for time-sensitive CMJ performance measures. Researchers and practitioners should include RSI and jump time with jump height to improve their assessment of jump performance.

  16. Designing driver assistance systems with crossmodal signals: multisensory integration rules for saccadic reaction times apply.

    Directory of Open Access Journals (Sweden)

    Rike Steenken

    Full Text Available Modern driver assistance systems make increasing use of auditory and tactile signals in order to reduce the driver's visual information load. This entails potential crossmodal interaction effects that need to be taken into account in designing an optimal system. Here we show that saccadic reaction times to visual targets (cockpit or outside mirror, presented in a driving simulator environment and accompanied by auditory or tactile accessories, follow some well-known spatiotemporal rules of multisensory integration, usually found under confined laboratory conditions. Auditory nontargets speed up reaction time by about 80 ms. The effect tends to be maximal when the nontarget is presented 50 ms before the target and when target and nontarget are spatially coincident. The effect of a tactile nontarget (vibrating steering wheel was less pronounced and not spatially specific. It is shown that the average reaction times are well-described by the stochastic "time window of integration" model for multisensory integration developed by the authors. This two-stage model postulates that crossmodal interaction occurs only if the peripheral processes from the different sensory modalities terminate within a fixed temporal interval, and that the amount of crossmodal interaction manifests itself in an increase or decrease of second stage processing time. A qualitative test is consistent with the model prediction that the probability of interaction, but not the amount of crossmodal interaction, depends on target-nontarget onset asynchrony. A quantitative model fit yields estimates of individual participants' parameters, including the size of the time window. Some consequences for the design of driver assistance systems are discussed.

  17. Theory of Visual Attention (TVA) applied to mice in the 5-choice serial reaction time task

    DEFF Research Database (Denmark)

    Fitzpatrick, C. M.; Caballero-Puntiverio, M.; Gether, U.

    2017-01-01

    Rationale The 5-choice serial reaction time task (5-CSRTT) is widely used to measure rodent attentional functions. In humans, many attention studies in healthy and clinical populations have used testing based on Bundesen’s Theory of Visual Attention (TVA) to estimate visual processing speeds...... thresholds and motor response baselines. Conclusions This study shows for the first time how 5-CSRTT performance in mice can be mathematically modelled to yield estimates of attentional capacity that are directly comparable to estimates from human studies....

  18. Development and validation of a Myxoma virus real-time polymerase chain reaction assay.

    Science.gov (United States)

    Albini, Sarah; Sigrist, Brigitte; Güttinger, Regula; Schelling, Claude; Hoop, Richard K; Vögtlin, Andrea

    2012-01-01

    To aid in the rapid diagnosis of myxomatosis in rabbits, a real-time polymerase chain reaction (PCR) for the specific detection of Myxoma virus is described. Primers and probe were designed to amplify a 147-bp fragment within the Serp2 gene. The assay was able to detect 23 copies of a synthesized oligo indicating a reliable sensitivity. In addition, the real-time PCR did not detect the Rabbit fibroma virus used in myxomatosis vaccines. The novel PCR was shown to be able to detect Myxoma virus in fresh and paraffin-embedded rabbit tissues originating from myxomatosis cases from various regions in Switzerland.

  19. Intra-individual reaction time variability and all-cause mortality over 17 years: a community-based cohort study.

    Science.gov (United States)

    Batterham, Philip J; Bunce, David; Mackinnon, Andrew J; Christensen, Helen

    2014-01-01

    very few studies have examined the association between intra-individual reaction time variability and subsequent mortality. Furthermore, the ability of simple measures of variability to predict mortality has not been compared with more complex measures. a prospective cohort study of 896 community-based Australian adults aged 70+ were interviewed up to four times from 1990 to 2002, with vital status assessed until June 2007. From this cohort, 770-790 participants were included in Cox proportional hazards regression models of survival. Vital status and time in study were used to conduct survival analyses. The mean reaction time and three measures of intra-individual reaction time variability were calculated separately across 20 trials of simple and choice reaction time tasks. Models were adjusted for a range of demographic, physical health and mental health measures. greater intra-individual simple reaction time variability, as assessed by the raw standard deviation (raw SD), coefficient of variation (CV) or the intra-individual standard deviation (ISD), was strongly associated with an increased hazard of all-cause mortality in adjusted Cox regression models. The mean reaction time had no significant association with mortality. intra-individual variability in simple reaction time appears to have a robust association with mortality over 17 years. Health professionals such as neuropsychologists may benefit in their detection of neuropathology by supplementing neuropsychiatric testing with the straightforward process of testing simple reaction time and calculating raw SD or CV.

  20. The Effects of Repeated Testing, Simulated Malingering, and Traumatic Brain Injury on Visual Choice Reaction Time

    Directory of Open Access Journals (Sweden)

    David L Woods

    2015-11-01

    Full Text Available Choice reaction time (CRT, the time required to discriminate and respond appropriately to different stimuli, is a basic measure of attention and processing speed. Here, we describe the reliability and clinical sensitivity of a new CRT test that presents lateralized visual stimuli and adaptively adjusts stimulus onset asynchronies (SOAs using a staircase procedure. Experiment 1 investigated the test-retest reliability in three test sessions at weekly intervals. Performance in the first test session was accurately predicted from age and computer-use regression functions obtained in a previously studied normative cohort. Central processing time (CentPT, the difference between the CRTs and simple reaction time latencies measured in a separate experiment, accounted for 55% of CRT latency and more than 50% of CRT latency variance. Performance improved significantly across the three test sessions. High intraclass correlation coefficients (ICCs were seen for CRTs (0.90, CentPTs (0.87, and an omnibus performance measure (0.81 that combined CRT and minimal SOA (mSOA z-scores. Experiment 2 investigated performance in the same participants when instructed to feign symptoms of traumatic brain injury (TBI: 87% produced abnormal omnibus z-scores. Simulated malingerers showed greater elevations in simple than choice reaction times, and hence reduced CentPTs. Latency-consistency z-scores, based on the difference between the CRTs obtained and those predicted from CentPT latencies, discriminated malingering participants from controls with high sensitivity and specificity. Experiment 3 investigated CRT test performance in military veterans who had suffered combat-related TBI and symptoms of post-traumatic stress disorder and revealed small but significant deficits in performance. The results indicate that the new CRT test shows high test-retest reliability, can assist in detecting participants performing with suboptimal effort, and is sensitive to the effects of

  1. Reaction Times to Consecutive Automation Failures: A Function of Working Memory and Sustained Attention.

    Science.gov (United States)

    Jipp, Meike

    2016-12-01

    This study explored whether working memory and sustained attention influence cognitive lock-up, which is a delay in the response to consecutive automation failures. Previous research has demonstrated that the information that automation provides about failures and the time pressure that is associated with a task influence cognitive lock-up. Previous research has also demonstrated considerable variability in cognitive lock-up between participants. This is why individual differences might influence cognitive lock-up. The present study tested whether working memory-including flexibility in executive functioning-and sustained attention might be crucial in this regard. Eighty-five participants were asked to monitor automated aircraft functions. The experimental manipulation consisted of whether or not an initial automation failure was followed by a consecutive failure. Reaction times to the failures were recorded. Participants' working-memory and sustained-attention abilities were assessed with standardized tests. As expected, participants' reactions to consecutive failures were slower than their reactions to initial failures. In addition, working-memory and sustained-attention abilities enhanced the speed with which participants reacted to failures, more so with regard to consecutive than to initial failures. The findings highlight that operators with better working memory and sustained attention have small advantages when initial failures occur, but their advantages increase across consecutive failures. The results stress the need to consider personnel selection strategies to mitigate cognitive lock-up in general and training procedures to enhance the performance of low ability operators. © 2016, Human Factors and Ergonomics Society.

  2. Reaction mechanisms and their interaction time in dissipative heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    De Rosa, A.; Fioretto, E.; Inglima, G.; Romoli, M.; Sandoli, M.; Setola, R. (Dipartimento di Scienze Fisiche Universita di Napoli Federico II Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Pad. 20 Mostra d' Oltremare, Napoli, (Italy)); Cardella, G.; Papa, M.; Pappalardo, G.; Rizzo, F.; Wang, Q. (Dipartimento di Fisica Universita di Catania Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia, 57 Catania, (Italy)); Napoli, D.R.; Scarlassara, F.; Segato, G.F.; Signorini, C.; Stefanini, A.M. (Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, Padova, (Italy))

    1990-05-01

    Angular distributions of fragments emitted in the reaction {sup 19}F+{sup 63}Cu measured in the range {theta}{sub lab}=10{degree} to 120{degree} at incident energy between 100 to 108 MeV (lab) have been analyzed according to available models for deep inelastic collisions with the aim to evidence different mechanisms contributing to such reactions. The analysis was performed in the framework of Strutinsky model taking into account both the development of Kun and of Abul-Magd and Simbel. To determine the interaction times, previously published excitation functions were also analyzed in the framework of Kun's model of cross section statistical fluctuations and near-side and far-side scattering were taken into account separately. It was pointed out that the rotational energy dissipation occurs in a limited angular range around the grazing angle. The presence of two distinct reaction mechanisms, each of them characterized by an interaction time, was also evidenced by comparing the energy averaged angular distributions to the Abul-Magd and Simbel model for dissipative collisions.

  3. Development of Capillary Loop Convective Polymerase Chain Reaction Platform with Real-Time Fluorescence Detection

    Directory of Open Access Journals (Sweden)

    Wen-Pin Chou

    2017-02-01

    Full Text Available Polymerase chain reaction (PCR has been one of the principal techniques of molecular biology and diagnosis for decades. Conventional PCR platforms, which work by rapidly heating and cooling the whole vessel, need complicated hardware designs, and cause energy waste and high cost. On the other hand, partial heating on the various locations of vessels to induce convective solution flows by buoyancy have been used for DNA amplification in recent years. In this research, we develop a new convective PCR platform, capillary loop convective polymerase chain reaction (clcPCR, which can generate one direction flow and make the PCR reaction more stable. The U-shaped loop capillaries with 1.6 mm inner diameter are designed as PCR reagent containers. The clcPCR platform utilizes one isothermal heater for heating the bottom of the loop capillary and a CCD device for detecting real-time amplifying fluorescence signals. The stable flow was generated in the U-shaped container and the amplification process could be finished in 25 min. Our experiments with different initial concentrations of DNA templates demonstrate that clcPCR can be applied for precise quantification. Multiple sample testing and real-time quantification will be achieved in future studies.

  4. Mathematical Modeling and Dynamic Simulation of Metabolic Reaction Systems Using Metabolome Time Series Data

    Directory of Open Access Journals (Sweden)

    Kansuporn eSriyudthsak

    2016-05-01

    Full Text Available The high-throughput acquisition of metabolome data is greatly anticipated for the complete understanding of cellular metabolism in living organisms. A variety of analytical technologies have been developed to acquire large-scale metabolic profiles under different biological or environmental conditions. Time series data are useful for predicting the most likely metabolic pathways because they provide important information regarding the accumulation of metabolites, which implies causal relationships in the metabolic reaction network. Considerable effort has been undertaken to utilize these data for constructing a mathematical model merging system properties and quantitatively characterizing a whole metabolic system in toto. However, there are technical difficulties between benchmarking the provision and utilization of data. Although hundreds of metabolites can be measured, which provide information on the metabolic reaction system, simultaneous measurement of thousands of metabolites is still challenging. In addition, it is nontrivial to logically predict the dynamic behaviors of unmeasurable metabolite concentrations without sufficient information on the metabolic reaction network. Yet, consolidating the advantages of advancements in both metabolomics and mathematical modeling remain to be accomplished. This review outlines the conceptual basis of and recent advances in technologies in both the research fields. It also highlights the potential for constructing a large-scale mathematical model by estimating model parameters from time series metabolome data in order to comprehensively understand metabolism at the systems level.

  5. Effect of Salivary Reaction Time on Flow Properties of Commercial Food Thickeners Used for Dysphagic Patients.

    Science.gov (United States)

    Lee, Hwa-Young; Yoon, Seung-Ro; Yoo, Whachun; Yoo, Byoungseung

    2016-01-01

    The effect of human saliva on the flow properties of pudding-like thickened water prepared with commercial food thickeners was investigated, and their viscosity differences were also compared as a function of salivary reaction time (0-60 min after the addition of saliva). Food thickeners used in this study were starch-based (SB), gum-containing starch-based (GSB), and gumbased (GB) commercial thickeners marketed in Korea. GB showed no significant reduction in viscosity upon contact with human saliva during the salivary reaction. In contrast, SB almost completely lost its viscosity shortly after the addition of saliva, and GSB significantly reduced its viscosity after 20 min of reaction time but retained its viscosity. The results of this study indicate that GB can enhance the swallowing safety of dysphagic patients by retaining a stable viscosity level without the reduction of viscosity during consumption of thickened fluids, whereas SB may increase the possibility of aspiration owing to a rapid decrease of viscosity upon contact with human saliva.

  6. Mathematical Modeling and Dynamic Simulation of Metabolic Reaction Systems Using Metabolome Time Series Data.

    Science.gov (United States)

    Sriyudthsak, Kansuporn; Shiraishi, Fumihide; Hirai, Masami Yokota

    2016-01-01

    The high-throughput acquisition of metabolome data is greatly anticipated for the complete understanding of cellular metabolism in living organisms. A variety of analytical technologies have been developed to acquire large-scale metabolic profiles under different biological or environmental conditions. Time series data are useful for predicting the most likely metabolic pathways because they provide important information regarding the accumulation of metabolites, which implies causal relationships in the metabolic reaction network. Considerable effort has been undertaken to utilize these data for constructing a mathematical model merging system properties and quantitatively characterizing a whole metabolic system in toto. However, there are technical difficulties between benchmarking the provision and utilization of data. Although, hundreds of metabolites can be measured, which provide information on the metabolic reaction system, simultaneous measurement of thousands of metabolites is still challenging. In addition, it is nontrivial to logically predict the dynamic behaviors of unmeasurable metabolite concentrations without sufficient information on the metabolic reaction network. Yet, consolidating the advantages of advancements in both metabolomics and mathematical modeling remain to be accomplished. This review outlines the conceptual basis of and recent advances in technologies in both the research fields. It also highlights the potential for constructing a large-scale mathematical model by estimating model parameters from time series metabolome data in order to comprehensively understand metabolism at the systems level.

  7. Monitoring Acidophilic Microbes with Real-Time Polymerase Chain Reaction (PCR) Assays

    Energy Technology Data Exchange (ETDEWEB)

    Frank F. Roberto

    2008-08-01

    Many techniques that are used to characterize and monitor microbial populations associated with sulfide mineral bioleaching require the cultivation of the organisms on solid or liquid media. Chemolithotrophic species, such as Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, or thermophilic chemolithotrophs, such as Acidianus brierleyi and Sulfolobus solfataricus can grow quite slowly, requiring weeks to complete efforts to identify and quantify these microbes associated with bioleach samples. Real-time PCR (polymerase chain reaction) assays in which DNA targets are amplified in the presence of fluorescent oligonucleotide primers, allowing the monitoring and quantification of the amplification reactions as they progress, provide a means of rapidly detecting the presence of microbial species of interest, and their relative abundance in a sample. This presentation will describe the design and use of such assays to monitor acidophilic microbes in the environment and in bioleaching operations. These assays provide results within 2-3 hours, and can detect less than 100 individual microbial cells.

  8. Preconditioned time-difference methods for advection-diffusion-reaction equations

    Energy Technology Data Exchange (ETDEWEB)

    Aro, C.; Rodrigue, G. [Lawrence Livermore National Lab., CA (United States); Wolitzer, D. [California State Univ., Hayward, CA (United States)

    1994-12-31

    Explicit time differencing methods for solving differential equations are advantageous in that they are easy to implement on a computer and are intrinsically very parallel. The disadvantage of explicit methods is the severe restrictions placed on stepsize due to stability. Stability bounds for explicit time differencing methods on advection-diffusion-reaction problems are generally quite severe and implicit methods are used instead. The linear systems arising from these implicit methods are large and sparse so that iterative methods must be used to solve them. In this paper the authors develop a methodology for increasing the stability bounds of standard explicit finite differencing methods by combining explicit methods, implicit methods, and iterative methods in a novel way to generate new time-difference schemes, called preconditioned time-difference methods.

  9. Attentional cues affect accuracy and reaction time via different cognitive and neural processes.

    Science.gov (United States)

    van Ede, Freek; de Lange, Floris P; Maris, Eric

    2012-07-25

    We investigated whether symbolic endogenous attentional cues affect perceptual accuracy and reaction time (RT) via different cognitive and neural processes. We recorded magnetoencephalography in 19 humans while they performed a cued somatosensory discrimination task in which the cue-target interval was varied between 0 and 1000 ms. Comparing behavioral and neural measures, we show that (1) attentional cueing affects accuracy and RT with different time courses and (2) the time course of our neural measure (anticipatory suppression of neuronal oscillations in stimulus-receiving sensory cortex) only accounts for the accuracy time course. A model is proposed in which the effect on accuracy is explained by a single process (preparatory excitability increase in sensory cortex), whereas the effect on RT is explained by an additional process that is sensitive to cue-target compatibility (post-target comparison between expected and actual stimulus location). These data provide new insights into the mechanisms underlying behavioral consequences of attentional cueing.

  10. Effect of Silane Reaction Time on the Repair of a Nanofilled Composite Using Tribochemical Treatment.

    Science.gov (United States)

    Pilo, Raphael; Brosh, Tamar; Geron, Valery; Levartovsky, Shifra; Eliades, George

    2016-01-01

    To investigate the influence of silane reaction time on the repair strength of an aged nanofilled composite and to characterize the bonding mechanism. Nanofilled composite disks (n = 110, Filtek Supreme XT) were aged for 90 days in water. After tribochemical treatment (CoJet-Sand), the specimens were assigned to 5 groups (n = 22), primed with silane (Espe-Sil), and left to react for 1, 2, 3, 4, and 5 min. A thin layer of adhesive (Visio-Bond) was applied and a new composite with the same dimension was placed and cured. Non-aged specimens immediately layered and cured using the incremental technique served as controls. After aging (30 days in water plus 5000 thermal cycles), the interface was subjected to a shearing force until failure. Failure mode was evaluated under a stereomicroscope and scanning electron microscopy (SEM). Additional aged and treated surfaces were evaluated for morphology as well as elemental and molecular composition using SEM/EDX and ATR-FTIR. The mean shear bond strength (SBS) of the repaired specimens was 53.9 ± 8.6 MPa, with no significant difference among the various reaction times, but significantly lower compared to the control (88.1 ± 12.5 MPa). Tribochemical treatment created an irregular surface morphology with particles imbedded in the aged surface. Interfacial SEM/EDX analysis showed a 5-μm non-uniform high atomic number zone rich in Al and Si. Tribochemical treatments for repairing composite using a short silane reaction period (1 min) are equally effective as the prolonged reaction periods (2 to 5 min), yielding interfacial shear strength of ~60% of unrepaired material.

  11. Rate of information processing and reaction time of aircraft pilots and non-pilots

    Directory of Open Access Journals (Sweden)

    Werner Barkhuizen

    2002-09-01

    Full Text Available Reaction time and rate of information processing are cited as critical components in the make-up of pilots. A need was identified to establish the validity of various chronometric measures in the selection of pilots. Fifty-eight military and commercial pilots and twenty non-pilots were subjected to Schepers’ Computerised Information Processing Test Battery, which measures reaction time, form discrimination time, colour discrimination time, rate of information processing (perceptual and rate of information processing (conceptual. Five hypotheses and one postulate were formulated and tested. The results indicate that pilots could be differentiated from non-pilots with 92,3% accuracy. However, the results need to be cross-validated before they are used for selection. Opsomming Reaksietyd en tempo van inligtingverwerking word as kritieke komponente in die samestelling van vlieëniers beskou. ‘n Behoefte is geïdentifiseer om die geldigheid van verskeie chronometriese metinge in vlieënierskeuring te bepaal. Agt en vyftig militêre en kommersiële vlieëniers en twintig nie-vlieëniers is onderwerp aan Schepers se Gerekenariseerde Inligtingverwerkingstoets-battery wat reaksietyd, vormdiskriminasietyd, kleurdiskriminasietyd, tempo van inligtingverwerking (perseptueel en tempo van inligtingverwerking (konseptueel meet. Vyf hipoteses en een postulaat is gestel en getoets. Die resultate dui daarop dat vlieëniers met 92,3% akkuraatheid van nievlieëniers onderskei kan word. Die resultate behoort egter eers gekruisvalideer te word voordat dit finaal vir keuring gebruik kan word.

  12. Assessment and Training of Visuomotor Reaction Time for Football Injury Prevention.

    Science.gov (United States)

    Wilkerson, Gary B; Simpson, Kevin A; Clark, Ryan A

    2017-01-01

    Neurocognitive reaction time has been associated with musculoskeletal injury risk, but visuomotor reaction time (VMRT) derived from tests that present greater challenges to visual stimulus detection and motor response execution may have a stronger association. To assess VMRT as a predictor of injury and the extent to which improvement may result from VMRT training. Cohort study. University athletic performance center. 76 National Collegiate Athletic Association Division-I FCS football players (19.5 ± 1.4 y, 1.85 ± 0.06 m, 102.98 ± 19.06 kg). Preparticipation and postseason assessments. A subset of players who exhibited slowest VMRT in relation to the cohort's postseason median value participated in a 6-wk training program. Injury occurrence was related to preparticipation VMRT, which was represented by both number of target hits in 60 s and average elapsed time between hits (ms). Receiver operating characteristic analysis identified the optimum cut point for a binary injury risk classification. A nonparametric repeated-measures analysis of ranks procedure was used to compare posttraining VMRT values for slow players who completed at least half of the training sessions (n = 15) with those for untrained fast players (n = 27). A preparticipation cut point of ≤85 hits (≥705 ms) discriminated injured from noninjured players with odds ratio = 2.30 (90% confidence interval, 1.05-5.06). Slow players who completed the training exhibited significant improvement in visuomotor performance compared with baseline (standardized response mean = 2.53), whereas untrained players exhibited a small performance decrement (group × trial interaction effect, L2 = 28.74; P injury risk factor for college football players. More research is needed to refine visuomotor reaction-time screening and training methods and to determine the extent to which improved performance values can reduce injury incidence.

  13. Defective sensorimotor integration in preparation for reaction time tasks in patients with multiple sclerosis.

    Science.gov (United States)

    Cabib, Christopher; Llufriu, Sara; Casanova-Molla, Jordi; Saiz, Albert; Valls-Solé, Josep

    2015-03-01

    Slowness of voluntary movements in patients with multiple sclerosis (MS) may be due to various factors, including attentional and cognitive deficits, delays in motor conduction time, and impairment of specific central nervous system circuits. In 13 healthy volunteers and 20 mildly disabled, relapsing-remitting MS patients, we examined simple reaction time (SRT) tasks requiring sensorimotor integration in circuits involving the corpus callosum and the brain stem. A somatosensory stimulus was used as the imperative signal (IS), and subjects were requested to react with either the ipsilateral or the contralateral hand (uncrossed vs. crossed SRT). In 33% of trials, a startling auditory stimulus was presented together with the IS, and the percentage reaction time change with respect to baseline SRT trials was measured (StartReact effect). The difference between crossed and uncrossed SRT, which requires interhemispheric conduction, was significantly larger in patients than in healthy subjects (P = 0.021). The StartReact effect, which involves activation of brain stem motor pathways, was reduced significantly in patients with respect to healthy subjects (uncrossed trials: P = 0.015; crossed trials: P = 0.005). In patients, a barely significant correlation was found between SRT delay and conduction abnormalities in motor and sensory pathways (P = 0.02 and P = 0.04, respectively). The abnormalities found specifically in trials reflecting interhemispheric transfer of information, as well as the evidence for reduced subcortical motor preparation, indicate that a delay in reaction time execution in MS patients cannot be explained solely by conduction slowing in motor and sensory pathways but suggest, instead, defective sensorimotor integration mechanisms in at least the two circuits examined. Copyright © 2015 The American Physiological Society.

  14. Opposite effects of sleep deprivation on the continuous reaction times in patients with liver cirrhosis and normal persons.

    Science.gov (United States)

    Lauridsen, Mette Munk; Frøjk, Jesper; de Muckadell, Ove B Schaffalitzky; Vilstrup, Hendrik

    2014-09-01

    The continuous reaction times (CRT) method describes arousal functions. Reaction time instability in a patient with liver disease indicates covert hepatic encephalopathy (cHE). The effects of sleep deprivation are unknown although cirrhosis patients frequently suffer from sleep disorders. The aim of this study was to determine if sleep deprivation influences the CRT test. Eighteen cirrhosis patients and 27 healthy persons were tested when rested and after one night's sleep deprivation. The patients filled out validated sleep quality questionnaires. Seven patients (38%) had unstable reaction times (a CRTindex sleep that was not related to their CRT tests before or after the sleep deprivation. In the healthy participants, the sleep deprivation slowed their reaction times by 11% (p sleep deprivation normalized or improved the reaction time stability of the patients with a CRTindex below 1.9 and had no effect in the patients with a CRTindex above 1.9. There was no relation between reported sleep quality and reaction time results. Thus, in cirrhosis patients, sleep disturbances do not lead to 'falsely' slowed and unstable reaction times. In contrast, the acute sleep deprivation slowed and destabilized the reaction times of the healthy participants. This may have negative consequences for decision-making.

  15. A Reaction Time Advantage for Calculating Beliefs over Public Representations Signals Domain Specificity for "Theory of Mind"

    Science.gov (United States)

    Cohen, Adam S.; German, Tamsin C.

    2010-01-01

    In a task where participants' overt task was to track the location of an object across a sequence of events, reaction times to unpredictable probes requiring an inference about a social agent's beliefs about the location of that object were obtained. Reaction times to false belief situations were faster than responses about the (false) contents of…

  16. Measuring Metacognition and Reaction Time: Further Findings on the Performances of General Education, Low-Achieving, and Institutionally Raised Students

    Science.gov (United States)

    Al-Hilawani, Yasser A.; Abdullah, Ahmad A.

    2010-01-01

    The purpose of this study was to use the picture format to examine in depth the metacognitive performances and reaction time in general education, low-achieving, and institutionally raised students. Results revealed that institutionally raised students, unlike low-achieving students, took significantly the longest reaction time to finish the test…

  17. Neuroticism Combined With Slower and More Variable Reaction Time: Synergistic Risk Factors for 7-Year Cognitive Decline in Females

    Science.gov (United States)

    Shickle, Darren A.; Roberts, Beverly A.; Deary, Ian J.

    2012-01-01

    Objective. Among adults, slower and more variable reaction times are associated with worse cognitive function and increased mortality risk. Therefore, it is important to elucidate risk factors for reaction time change over the life course. Method. Data from the Health and Lifestyle Survey (HALS) were used to examine predictors of 7-year decline in reaction time (N = 4,260). Regression-derived factor scores were used to summarize general change across 4 reaction time variables: simple mean, 4-choice mean, simple variability, and 4-choice variability (53.52% of variance). Results. Age (B = .02, p reaction time (B = −.10, p = .001) were significant risk factors for males (N = 1,899). In addition to these variables, in females (N = 2,361), neuroticism was significant and interacted synergistically with baseline reaction time (B = .06, p = .04). Adjustment for physiological variables explained the interaction with neuroticism, suggesting that candidate mechanisms had been identified. Discussion. A priority for future research is to replicate interactions between personality and reaction time in other samples and find specific mechanisms. Stratification of population data on cognitive health by personality and reaction time could improve strategies for identifying those at greater risk of cognitive decline. PMID:22367712

  18. Choice reaction times for human head rotations are shortened by startling acoustic stimuli, irrespective of stimulus direction

    NARCIS (Netherlands)

    Oude Nijhuis, L.B.; Janssen, L.; Bloem, B.R.; Dijk, J.G. van; Gielen, C.C.A.M.; Borm, G.F.; Overeem, S.

    2007-01-01

    Auditory startle reflexes can accelerate simple voluntary reaction times (StartReact effect). To investigate the role of startle reflexes on more complex motor behaviour we formulated two questions: (1) can auditory startle reflexes shorten choice reaction times?; (2) is the StartReact effect

  19. Reliability of the dynavision™ d2 for assessing reaction time performance.

    Science.gov (United States)

    Wells, Adam J; Hoffman, Jay R; Beyer, Kyle S; Jajtner, Adam R; Gonzalez, Adam M; Townsend, Jeremy R; Mangine, Gerald T; Robinson, Edward H; McCormack, William P; Fragala, Maren S; Stout, Jeffrey R

    2014-01-01

    Recently, the Dynavision™ D2 Visuomotor Training Device (D2) has emerged as a tool in the assessment of reaction time (RT); however, information regarding the reliability of the D2 have been limited, and to date, reliability data have been limited to non- generalizable samples. Therefore, the purpose of this study was to establish intraclass correlation coefficients (ICC2,1) for the D2 that are generalizable across a population of recreationally active young adults. Forty-two recreationally active men and women (age: 23.41 ± 4.84 years; height: 1.72 ± 0.11 m; mass: 76.62 ± 18.26 Kg) completed 6 trials for three RT tasks of increasing complexity. Each trial was separated by at least 48-hours. A repeated measures ANOVA was used to detect differences in performance across the six trials. Intraclass correlation coefficients (ICC2,1) standard error of measurement (SEM), and minimal differences (MD) were used to determine the reliability of the D2 from the two sessions with the least significant difference score. Moderate to strong reliability was demonstrated for visual RT (ICC2,1: 0.84, SEM: 0.033), and reactive ability in both Mode A and Mode B tasks (Mode A hits: ICC2,1: 0.75, SEM: 5.44; Mode B hits: ICC2,1: 0.73, SEM: 8.57). Motor RT (ICC2,1: 0.63, SEM: 0.035s) showed fair reliability, while average RT per hit for Modes A and B showed moderate reliability (ICC2,1: 0.68, SEM: 0.43 s and ICC2,1: 0.72, SEM: 0.03 s respectively). It appears that one familiarization trial is necessary for the choice reaction time (CRT) task while three familiarization trials are necessary for reactive RT tasks. In conclusion, results indicate that the Dynavision™ D2 is a reliable device to assess neuromuscular reactivity given that an adequate practice is provided. The data presented are generalizable to a population of recreationally active young adults. Key PointsThe Dynavision™ D2 is a light-training reaction device, developed to train sensory motor integration through the

  20. Opposite effects of sleep deprivation on the continuous reaction times in patients with liver cirrhosis and normal persons

    DEFF Research Database (Denmark)

    Lauridsen, Mette Munk; Frøjk, Jesper; de Muckadell, Ove B Schaffalitzky

    2014-01-01

    The continuous reaction times (CRT) method describes arousal functions. Reaction time instability in a patient with liver disease indicates covert hepatic encephalopathy (cHE). The effects of sleep deprivation are unknown although cirrhosis patients frequently suffer from sleep disorders. The aim...... no effect in the patients with a CRTindex above 1.9. There was no relation between reported sleep quality and reaction time results. Thus, in cirrhosis patients, sleep disturbances do not lead to 'falsely' slowed and unstable reaction times. In contrast, the acute sleep deprivation slowed and destabilized...... of this study was to determine if sleep deprivation influences the CRT test. Eighteen cirrhosis patients and 27 healthy persons were tested when rested and after one night's sleep deprivation. The patients filled out validated sleep quality questionnaires. Seven patients (38 %) had unstable reaction times (a...

  1. Use of virtual reality intervention to improve reaction time in children with cerebral palsy: A randomized controlled trial.

    Science.gov (United States)

    Pourazar, Morteza; Mirakhori, Fatemeh; Hemayattalab, Rasool; Bagherzadeh, Fazlolah

    2017-09-21

    The purpose of this study was to investigate the training effects of Virtual Reality (VR) intervention program on reaction time in children with cerebral palsy. Thirty boys ranging from 7 to 12 years (mean = 11.20; SD = .76) were selected by available sampling method and randomly divided into the experimental and control groups. Simple Reaction Time (SRT) and Discriminative Reaction Time (DRT) were measured at baseline and 1 day after completion of VR intervention. Multivariate analysis of variance (MANOVA) and paired sample t-test were performed to analyze the results. MANOVA test revealed significant effects for group in posttest phase, with lower reaction time in both measures for the experimental group. Based on paired sample t-test results, both RT measures significantly improved in experimental group following the VR intervention program. This paper proposes VR as a promising tool into the rehabilitation process for improving reaction time in children with cerebral palsy.

  2. Emotions over time: synchronicity and development of subjective, physiological, and facial affective reactions to music.

    Science.gov (United States)

    Grewe, Oliver; Nagel, Frederik; Kopiez, Reinhard; Altenmüller, Eckart

    2007-11-01

    Most people are able to identify basic emotions expressed in music and experience affective reactions to music. But does music generally induce emotion? Does it elicit subjective feelings, physiological arousal, and motor reactions reliably in different individuals? In this interdisciplinary study, measurement of skin conductance, facial muscle activity, and self-monitoring were synchronized with musical stimuli. A group of 38 participants listened to classical, rock, and pop music and reported their feelings in a two-dimensional emotion space during listening. The first entrance of a solo voice or choir and the beginning of new sections were found to elicit interindividual changes in subjective feelings and physiological arousal. Quincy Jones' "Bossa Nova" motivated movement and laughing in more than half of the participants. Bodily reactions such as "goose bumps" and "shivers" could be stimulated by the "Tuba Mirum" from Mozart's Requiem in 7 of 38 participants. In addition, the authors repeated the experiment seven times with one participant to examine intraindividual stability of effects. This exploratory combination of approaches throws a new light on the astonishing complexity of affective music listening.

  3. Reaction time in the agility test under simulated competitive and noncompetitive conditions.

    Science.gov (United States)

    Zemková, Erika; Vilman, Tomáš; Kováčiková, Zuzana; Hamar, Dušan

    2013-12-01

    The study evaluates a reaction time in the Agility Test under simulated competitive and noncompetitive conditions. A group of 16 fit men performed, in random order, 2 versions of the Agility Test: non-competitive Agility Single and Agility Dual in form of simulated competition. In both cases, subjects had to touch, as fast as possible, with either the left or the right foot 1 of 4 mats located in 4 corners outside of an 80 cm square. Mats had to be touched in accordance with the location of the stimulus in one of the corners of the screen. The test consisted of 20 visual stimuli with random generation of their location on the screen and time generation from 500 to 2,500 milliseconds. The result was total reaction time (RT) for all 20 reactions measured by a PC-based system FiTRO Agility Check. Results showed significantly (p Agility Dual than in the Agility Single Test (690.6 ± 83.8 milliseconds and 805.8 ± 101.1 milliseconds, respectively). Further comparisons of RT under noncompetitive and simulated competitive conditions for the best 8 subjects proceeded in the second match showed a decrease from 781.3 ± 111.2 milliseconds to 693.6 ± 97.8 milliseconds in the first match and to 637.0 ± 53.0 milliseconds in the second match. It may be concluded that RT is better when the Agility Test is performed in simulated competitive than noncompetitive conditions. The Agility Test in form of competition may be used for children and young athletes to enhance their attention level and motivation.

  4. Anticipation measures of sequence learning: manual versus oculomotor versions of the serial reaction time task.

    Science.gov (United States)

    Vakil, Eli; Bloch, Ayala; Cohen, Haggar

    2017-03-01

    The serial reaction time (SRT) task has generated a very large amount of research. Nevertheless the debate continues as to the exact cognitive processes underlying implicit sequence learning. Thus, the first goal of this study is to elucidate the underlying cognitive processes enabling sequence acquisition. We therefore compared reaction time (RT) in sequence learning in a standard manual activated (MA) to that in an ocular activated (OA) version of the task, within a single experimental setting. The second goal is to use eye movement measures to compare anticipation, as an additional indication of sequence learning, between the two versions of the SRT. Performance of the group given the MA version of the task (n = 29) was compared with that of the group given the OA version (n = 30). The results showed that although overall, RT was faster for the OA group, the rate of sequence learning was similar to that of the MA group performing the standard version of the SRT. Because the stimulus-response association is automatic and exists prior to training in the OA task, the decreased reaction time in this version of the task reflects a purer measure of the sequence learning that occurs in the SRT task. The results of this study show that eye tracking anticipation can be measured directly and can serve as a direct measure of sequence learning. Finally, using the OA version of the SRT to study sequence learning presents a significant methodological contribution by making sequence learning studies possible among populations that struggle to perform manual responses.

  5. DHA- RICH FISH OIL IMPROVES COMPLEX REACTION TIME IN FEMALE ELITE SOCCER PLAYERS

    Directory of Open Access Journals (Sweden)

    José F. Guzmán

    2011-06-01

    Full Text Available Omega-3 fatty acids (n-3 has shown to improve neuromotor function. This study examined the effects of docosahexaenoic acid (DHA on complex reaction time, precision and efficiency, in female elite soccer players. 24 players from two Spanish female soccer Super League teams were randomly selected and assigned to two experimental groups, then administered, in a double-blind manner, 3.5 g·day-1 of either DHA-rich fish oil (FO =12 or olive oil (OO = 12 over 4 weeks of training. Two measurements (pre- and post-treatment of complex reaction time and precision were taken. Participants had to press different buttons and pedals with left and right hands and feet, or stop responding, according to visual and auditory stimuli. Multivariate analysis of variance displayed an interaction between supplement administration (pre/post and experimental group (FO/OO on complex reaction time (FO pre = 0.713 ± 0.142 ms, FO post = 0.623 ± 0.109 ms, OO pre = 0.682 ± 1.132 ms, OO post = 0.715 ± 0.159 ms; p = 0.004 and efficiency (FO pre = 40.88 ± 17.41, FO post = 57.12 ± 11.05, OO pre = 49.52 ± 14.63, OO post = 49. 50 ± 11.01; p = 0.003. It was concluded that after 4 weeks of supplementation with FO, there was a significant improvement in the neuromotor function of female elite soccer players

  6. Inattention and Reaction Time Variability Are Linked to Ventromedial Prefrontal Volume in Adolescents.

    Science.gov (United States)

    Albaugh, Matthew D; Orr, Catherine; Chaarani, Bader; Althoff, Robert R; Allgaier, Nicholas; D'Alberto, Nicholas; Hudson, Kelsey; Mackey, Scott; Spechler, Philip A; Banaschewski, Tobias; Brühl, Rüdiger; Bokde, Arun L W; Bromberg, Uli; Büchel, Christian; Cattrell, Anna; Conrod, Patricia J; Desrivières, Sylvane; Flor, Herta; Frouin, Vincent; Gallinat, Jürgen; Goodman, Robert; Gowland, Penny; Grimmer, Yvonne; Heinz, Andreas; Kappel, Viola; Martinot, Jean-Luc; Paillère Martinot, Marie-Laure; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Penttila, Jani; Poustka, Luise; Paus, Tomáš; Smolka, Michael N; Struve, Maren; Walter, Henrik; Whelan, Robert; Schumann, Gunter; Garavan, Hugh; Potter, Alexandra S

    2017-11-01

    Neuroimaging studies of attention-deficit/hyperactivity disorder (ADHD) have most commonly reported volumetric abnormalities in the basal ganglia, cerebellum, and prefrontal cortices. Few studies have examined the relationship between ADHD symptomatology and brain structure in population-based samples. We investigated the relationship between dimensional measures of ADHD symptomatology, brain structure, and reaction time variability-an index of lapses in attention. We also tested for associations between brain structural correlates of ADHD symptomatology and maps of dopaminergic gene expression. Psychopathology and imaging data were available for 1538 youths. Parent ratings of ADHD symptoms were obtained using the Development and Well-Being Assessment and the Strengths and Difficulties Questionnaire (SDQ). Self-reports of ADHD symptoms were assessed using the youth version of the SDQ. Reaction time variability was available in a subset of participants. For each measure, whole-brain voxelwise regressions with gray matter volume were calculated. Parent ratings of ADHD symptoms (Development and Well-Being Assessment and SDQ), adolescent self-reports of ADHD symptoms on the SDQ, and reaction time variability were each negatively associated with gray matter volume in an overlapping region of the ventromedial prefrontal cortex. Maps of DRD1 and DRD2 gene expression were associated with brain structural correlates of ADHD symptomatology. This is the first study to reveal relationships between ventromedial prefrontal cortex structure and multi-informant measures of ADHD symptoms in a large population-based sample of adolescents. Our results indicate that ventromedial prefrontal cortex structure is a biomarker for ADHD symptomatology. These findings extend previous research implicating the default mode network and dopaminergic dysfunction in ADHD. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  7. Evaluation of a real-time polymerase chain reaction assay for the detection of Dientamoeba fragilis.

    Science.gov (United States)

    Calderaro, Adriana; Gorrini, Chiara; Montecchini, Sara; Peruzzi, Simona; Piccolo, Giovanna; Rossi, Sabina; Gargiulo, Franco; Manca, Nino; Dettori, Giuseppe; Chezzi, Carlo

    2010-07-01

    The diagnostic value of a real-time polymerase chain reaction (PCR) assay targeting the 5.8S rDNA of Dientamoeba fragilis was investigated as compared with conventional parasitologic methods including cultivation testing 959 fecal samples from 491 patients attending a tertiary-care hospital and suspected of having an intestinal parasitosis. The real-time PCR assay revealed 117 additional D. fragilis-positive samples as compared with conventional methods, showing 100% sensitivity and specificity in our experience. On the whole, D. fragilis infection was detected in 186 samples from 105 patients (21.4%, third in frequency among the diagnosed intestinal parasitoses). The evaluated real-time PCR assay represents an effective tool to obtain both an accurate diagnosis and a reliable epidemiologic picture of dientamoebiasis.

  8. Measurement of Visual Reaction Times Using Hand-held Mobile Devices

    Science.gov (United States)

    Mulligan, Jeffrey B.; Arsintescu, Lucia; Flynn-Evans, Erin

    2015-01-01

    Modern mobile devices provide a convenient platform for collecting research data in the field. But,because the working of these devices is often cloaked behind multiple layers of proprietary system software, it can bedifficult to assess the accuracy of the data they produce, particularly in the case of timing. We have been collecting datain a simple visual reaction time experiment, as part of a fatigue testing protocol known as the Psychomotor Vigilance Test (PVT). In this protocol, subjects run a 5-minute block consisting of a sequence of trials in which a visual stimulus appears after an unpredictable variable delay. The subject is required to tap the screen as soon as possible after the appearance of the stimulus. In order to validate the reaction times reported by our program, we had subjects perform the task while a high-speed video camera recorded both the display screen, and a side view of the finger (observed in a mirror). Simple image-processing methods were applied to determine the frames in which the stimulus appeared and disappeared, and in which the finger made and broke contact with the screen. The results demonstrate a systematic delay between the initial contact by the finger and the detection of the touch by the software, having a value of 80 +- 20 milliseconds.

  9. Studies of the accuracy of time integration methods for reaction-diffusion equations

    Science.gov (United States)

    Ropp, David L.; Shadid, John N.; Ober, Curtis C.

    2004-03-01

    In this study we present numerical experiments of time integration methods applied to systems of reaction-diffusion equations. Our main interest is in evaluating the relative accuracy and asymptotic order of accuracy of the methods on problems which exhibit an approximate balance between the competing component time scales. Nearly balanced systems can produce a significant coupling of the physical mechanisms and introduce a slow dynamical time scale of interest. These problems provide a challenging test for this evaluation and tend to reveal subtle differences between the various methods. The methods we consider include first- and second-order semi-implicit, fully implicit, and operator-splitting techniques. The test problems include a prototype propagating nonlinear reaction-diffusion wave, a non-equilibrium radiation-diffusion system, a Brusselator chemical dynamics system and a blow-up example. In this evaluation we demonstrate a "split personality" for the operator-splitting methods that we consider. While operator-splitting methods often obtain very good accuracy, they can also manifest a serious degradation in accuracy due to stability problems.

  10. Computational solutions of unified fractional reaction-diffusion equations with composite fractional time derivative

    Science.gov (United States)

    Saxena, R. K.; Mathai, A. M.; Haubold, H. J.

    2015-10-01

    This paper deals with the investigation of the computational solutions of an unified fractional reaction-diffusion equation, which is obtained from the standard diffusion equation by replacing the time derivative of first order by the generalized fractional time-derivative defined by Hilfer (2000), the space derivative of second order by the Riesz-Feller fractional derivative and adding the function ϕ (x, t) which is a nonlinear function governing reaction. The solution is derived by the application of the Laplace and Fourier transforms in a compact and closed form in terms of the H-function. The main result obtained in this paper provides an elegant extension of the fundamental solution for the space-time fractional diffusion equation obtained earlier by Mainardi et al. (2001, 2005) and a result very recently given by Tomovski et al. (2011). Computational representation of the fundamental solution is also obtained explicitly. Fractional order moments of the distribution are deduced. At the end, mild extensions of the derived results associated with a finite number of Riesz-Feller space fractional derivatives are also discussed.

  11. Interhemispheric versus stimulus-response spatial compatibility effects in bimanual reaction times to lateralized visual stimuli

    Directory of Open Access Journals (Sweden)

    Antonello ePellicano

    2013-06-01

    Full Text Available In the present study, we tested right- and left-handed participants in a Poffenberger paradigm with bimanual responses and hands either in an anatomical or in a left-right inverted posture. We observed a significant positive crossed-uncrossed difference (CUD in reaction times for both manual dominance groups and both response postures. These results rule out an explanation of the CUD in terms of stimulus-response spatial compatibility and provide convincing evidence on the important role of interhemispheric callosal transfer in bimanual responding in right- as well as left-handed individuals.

  12. The Visual and Auditory Reaction Time of Adolescents with Respect to Their Academic Achievements

    Science.gov (United States)

    Taskin, Cengiz

    2016-01-01

    The aim of this study was to examine in visual and auditory reaction time of adolescents with respect to their academic achievement level. Five hundred adolescent children from the Turkey, (age=15.24±0.78 years; height=168.80±4.89 cm; weight=65.24±4.30 kg) for two hundred fifty male and (age=15.28±0.74; height=160.40±5.77 cm; weight=55.32±4.13 kg)…

  13. Density-Dependent Conformable Space-time Fractional Diffusion-Reaction Equation and Its Exact Solutions

    Science.gov (United States)

    Hosseini, Kamyar; Mayeli, Peyman; Bekir, Ahmet; Guner, Ozkan

    2018-01-01

    In this article, a special type of fractional differential equations (FDEs) named the density-dependent conformable fractional diffusion-reaction (DDCFDR) equation is studied. Aforementioned equation has a significant role in the modelling of some phenomena arising in the applied science. The well-organized methods, including the \\exp (-φ (\\varepsilon )) -expansion and modified Kudryashov methods are exerted to generate the exact solutions of this equation such that some of the solutions are new and have been reported for the first time. Results illustrate that both methods have a great performance in handling the DDCFDR equation.

  14. Useful Field of View in Simulated Driving: Reaction Times and Eye Movements of Drivers

    Directory of Open Access Journals (Sweden)

    Yasuhiro Seya

    2013-06-01

    Full Text Available To examine the spatial distribution of a useful field of view (UFOV in driving, reaction times (RTs and eye movements were measured in simulated driving. In the experiment, a normal or mirror-reversed letter “E” was presented on driving images with different eccentricities and directions from the current gaze position. The results showed significantly slower RTs in the upper and upper left directions than in the other directions. The RTs were significantly slower in the left directions than in the right directions. These results suggest that the UFOV in driving may be asymmetrical among the meridians in the visual field.

  15. Reaction time as a stochastic process implemented by functional brain networks.

    Science.gov (United States)

    Siettos, Constantinos I; Smyrnis, Nikolaos

    2017-04-01

    Many studies focus on anatomical brain connectivity in an effort to explain the effect of practice on reaction time (RT) that is observed in many cognitive tasks. In this commentary, we suggest that RT reflects a stochastic process that varies in each single repetition of any cognitive task and cannot be attributed only to anatomical properties of the underlying neuronal circuit. Based on recent evidence from Magnetoencephalographic, Electroencephalographic, and fMRI studies, we further propose that the functional properties of key brain areas and their self-organization into functional connectivity networks contribute to the RT and could also explain the effects of training on the distribution of the RT.

  16. [Antigenemia and real time polymerase chain reaction for diagnosis of cytomegalovirus disease in HIV infected adults].

    Science.gov (United States)

    Luchsinger, Vivían; Vásquez, Patricia; Silva, Matías; Bruno, M José; Siches, Izkia; Villarroel, Javier; Garmendia, M Luisa; Larrañaga, Carmen

    2015-12-01

    Cytomegalovirus (CMV) infection is frequent in HIV adults. It is unknown usefulness of quantitative methods for diagnosing the CMV disease in Chilean patients. To determine the performance of antigenemia and real time polymerase chain reaction (rtPCR) in the diagnosis of CMV disease in Chilean HIV adults. Detection of CMV by viral isolation (AVR), antigenemia and quantitative rtPCR in HIV adults. The 102 adults with suspected CMV disease had lower LTCD4 count and higher HIV viral load than 77 patients without suspicion (p HIV adults. AVR is inappropriate as a gold standard for its low performance.

  17. The continuous reaction times method for diagnosing, grading, and monitoring minimal/covert hepatic encephalopathy

    DEFF Research Database (Denmark)

    Lauridsen, Mette Enok Munk; Thiele, Maja; Kimer, N

    2013-01-01

    ) as a parameter of reaction time variability. The index is a measure of alertness stability and is used to assess attention and cognition deficits. The CRTindex identifies half of patients in a Danish cohort with chronic liver disease, as having m/cHE, a normal value safely precludes HE, it has a broad outcome...... span reflecting the degree of brain impairment, it shows no learning effect, and it is independent on age and gender. The CRTindex is, therefore, a candidate tool for routine screening, detecting, grading, and monitoring m/cHE. Still, however, further methodological and clinical validation trials...

  18. The continuous reaction times method for diagnosing, grading, and monitoring minimal/covert hepatic encephalopathy

    DEFF Research Database (Denmark)

    Lauridsen, Mette Enok Munk; Thiele, Maja; Kimer, Nina

    2013-01-01

    -10) percentile) as a parameter of reaction time variability. The index is a measure of alertness stability and is used to assess attention and cognition deficits. The CRTindex identifies half of patients in a Danish cohort with chronic liver disease, as having m/cHE, a normal value safely precludes HE, it has...... a broad outcome span reflecting the degree of brain impairment, it shows no learning effect, and it is independent on age and gender. The CRTindex is, therefore, a candidate tool for routine screening, detecting, grading, and monitoring m/cHE. Still, however, further methodological and clinical validation...

  19. Is reaction time an index of white matter connectivity during training?

    Science.gov (United States)

    Kuang, Shenbing

    2017-04-01

    Voelker et al. (this issue) discuss the idea of linking white matter (WM) plasticity to improved reaction time (RT) during training. While compelling, this argument has important confounds and should be taken with cautions. RT is constrained not only by the speed of signal transmission in WM, but also by the properties of synaptic and neural processing in cortical gray matter. It is still unclear to what extent RT variability could be explained by WM plasticity and cortical plasticity. Future studies should examine both WM plasticity and cortical plasticity in relation to RT changes, to fully understand the brain mechanisms underlying RT improvement during training.

  20. Reference data on reaction time and aging using the Nintendo Wii Balance Board

    DEFF Research Database (Denmark)

    Blomkvist, Andreas W.; Eika, Fredrik; Rahbek, Martin T.

    2017-01-01

    Background Falls among older adults is one of the major public health challenges facing the rapidly changing demography. The valid assessment of reaction time (RT) and other well-documented risk factors for falls are mainly restricted to specialized clinics due to the equipment needed. The Nintendo...... participants were recruited at various locations and their RT in hands and feet were tested by six assessors using the Nintendo Wii Balance Board. Reference data were ana-lysed and presented in age-groups, while the age-related change in RT was tested and characterized with linear regression models. Results...... and gender on RT....

  1. Estimating time-to-onset of adverse drug reactions from spontaneous reporting databases.

    Science.gov (United States)

    Leroy, Fanny; Dauxois, Jean-Yves; Théophile, Hélène; Haramburu, Françoise; Tubert-Bitter, Pascale

    2014-02-03

    Analyzing time-to-onset of adverse drug reactions from treatment exposure contributes to meeting pharmacovigilance objectives, i.e. identification and prevention. Post-marketing data are available from reporting systems. Times-to-onset from such databases are right-truncated because some patients who were exposed to the drug and who will eventually develop the adverse drug reaction may do it after the time of analysis and thus are not included in the data. Acknowledgment of the developments adapted to right-truncated data is not widespread and these methods have never been used in pharmacovigilance. We assess the use of appropriate methods as well as the consequences of not taking right truncation into account (naive approach) on parametric maximum likelihood estimation of time-to-onset distribution. Both approaches, naive or taking right truncation into account, were compared with a simulation study. We used twelve scenarios for the exponential distribution and twenty-four for the Weibull and log-logistic distributions. These scenarios are defined by a set of parameters: the parameters of the time-to-onset distribution, the probability of this distribution falling within an observable values interval and the sample size. An application to reported lymphoma after anti TNF- α treatment from the French pharmacovigilance is presented. The simulation study shows that the bias and the mean squared error might in some instances be unacceptably large when right truncation is not considered while the truncation-based estimator shows always better and often satisfactory performances and the gap may be large. For the real dataset, the estimated expected time-to-onset leads to a minimum difference of 58 weeks between both approaches, which is not negligible. This difference is obtained for the Weibull model, under which the estimated probability of this distribution falling within an observable values interval is not far from 1. It is necessary to take right truncation into

  2. Factors Affecting the Timing of Signal Detection of Adverse Drug Reactions.

    Directory of Open Access Journals (Sweden)

    Masayuki Hashiguchi

    Full Text Available We investigated factors affecting the timing of signal detection by comparing variations in reporting time of known and unknown ADRs after initial drug release in the USA. Data on adverse event reactions (AERs submitted to U.S. FDA was used. Six ADRs associated with 6 drugs (rosuvastatin, aripiprazole, teriparatide, telithromycin, exenatide, varenicline were investigated: Changes in the proportional reporting ratio, reporting odds ratio, and information component as indexes of signal detection were followed every 3 months after each drugs release, and the time for detection of signals was investigated. The time for the detection of signal to be detected after drug release in the USA was 2-10 months for known ADRs and 19-44 months for unknown ones. The median lag time for known and unknown ADRs was 99.0-122.5 days and 185.5-306.0 days, respectively. When the FDA released advisory information on rare but potentially serious health risks of an unknown ADR, the time lag to report from the onset of ADRs to the FDA was shorter. This study suggested that one factor affecting signal detection time is whether an ADR was known or unknown at release.

  3. [Methods Used for Monitoring Cure Reactions in Real-time in an Autoclave

    Science.gov (United States)

    Cooper, John B.; Wise, Kent L.; Jensen, Brian J. (Technical Monitor)

    2000-01-01

    The goal of the research was to investigate methods for monitoring cure reactions in real-time in an autoclave. This is of particular importance to NASA Langley Research Center because polyimides were proposed for use in the High Speed Civil Transport (HSCT) program. Understanding the cure chemistry behind the polyimides would allow for intelligent processing of the composites made from their use. This work has led to two publications in peer-reviewed journals and a patent. The journal articles are listed as Appendix A which is on the instrument design of the research and Appendix B which is on the cure chemistry. Also, a patent has been awarded for the instrumental design developed under this grant which is given as Appendix C. There has been a significant amount of research directed at developing methods for monitoring cure reactions in real-time within the autoclave. The various research efforts can be categorized as methods providing either direct chemical bonding information or methods that provide indirect chemical bonding information. Methods falling into the latter category are fluorescence, dielectric loss, ultrasonic and similar type methods. Correlation of such measurements with the underlying chemistry is often quite difficult since these techniques do not allow monitoring of the curing chemistry which is ultimately responsible for material properties. Direct methods such as vibrational spectroscopy, however, can often be easily correlated with the underlying chemistry of a reaction. Such methods include Raman spectroscopy, mid-IR absorbance, and near-IR absorbance. With the recent advances in fiber-optics, these spectroscopic techniques can be applied to remote on-line monitoring.

  4. New time-scale criteria for model simplification of bio-reaction systems

    Directory of Open Access Journals (Sweden)

    Lee Sang

    2008-08-01

    Full Text Available Abstract Background Quasi-steady state approximation (QSSA based on time-scale analysis is known to be an effective method for simplifying metabolic reaction system, but the conventional analysis becomes time-consuming and tedious when the system is large. Although there are automatic methods, they are based on eigenvalue calculations of the Jacobian matrix and on linear transformations, which have a high computation cost. A more efficient estimation approach is necessary for complex systems. Results This work derived new time-scale factor by focusing on the problem structure. By mathematically reasoning the balancing behavior of fast species, new time-scale criteria were derived with a simple expression that uses the Jacobian matrix directly. The algorithm requires no linear transformation or decomposition of the Jacobian matrix, which has been an essential part for previous automatic time-scaling methods. Furthermore, the proposed scale factor is estimated locally. Therefore, an iterative procedure was also developed to find the possible multiple boundary layers and to derive an appropriate reduced model. Conclusion By successive calculation of the newly derived time-scale criteria, it was possible to detect multiple boundary layers of full ordinary differential equation (ODE models. Besides, the iterative procedure could derive the appropriate reduced differential algebraic equation (DAE model with consistent initial values, which was tested with simple examples and a practical example.

  5. Reaction time effects in lab- versus Web-based research: Experimental evidence.

    Science.gov (United States)

    Hilbig, Benjamin E

    2016-12-01

    Although Web-based research is now commonplace, it continues to spur skepticism from reviewers and editors, especially whenever reaction times are of primary interest. Such persistent preconceptions are based on arguments referring to increased variation, the limits of certain software and technologies, and a noteworthy lack of comparisons (between Web and lab) in fully randomized experiments. To provide a critical test, participants were randomly assigned to complete a lexical decision task either (a) in the lab using standard experimental software (E-Prime), (b) in the lab using a browser-based version (written in HTML and JavaScript), or (c) via the Web using the same browser-based version. The classical word frequency effect was typical in size and corresponded to a very large effect in all three conditions. There was no indication that the Web- or browser-based data collection was in any way inferior. In fact, if anything, a larger effect was obtained in the browser-based conditions than in the condition relying on standard experimental software. No differences between Web and lab (within the browser-based conditions) could be observed, thus disconfirming any substantial influence of increased technical or situational variation. In summary, the present experiment contradicts the still common preconception that reaction time effects of only a few hundred milliseconds cannot be detected in Web experiments.

  6. Real-time and in situ monitoring of mechanochemical milling reactions

    Science.gov (United States)

    Friščić, Tomislav; Halasz, Ivan; Beldon, Patrick J.; Belenguer, Ana M.; Adams, Frank; Kimber, Simon A. J.; Honkimäki, Veijo; Dinnebier, Robert E.

    2013-01-01

    Chemical and structural transformations have long been carried out by milling. Such mechanochemical steps are now ubiquitous in a number of industries (such as the pharmaceutical, chemical and metallurgical industries), and are emerging as excellent environmentally friendly alternatives to solution-based syntheses. However, mechanochemical transformations are typically difficult to monitor in real time, which leaves a large gap in the mechanistic understanding required for their development. We now report the real-time study of mechanochemical transformations in a ball mill by means of in situ diffraction of high-energy synchrotron X-rays. Focusing on the mechanosynthesis of metal-organic frameworks, we have directly monitored reaction profiles, the formation of intermediates, and interconversions of framework topologies. Our results reveal that mechanochemistry is highly dynamic, with reaction rates comparable to or greater than those in solution. The technique also enabled us to probe directly how catalytic additives recently introduced in the mechanosynthesis of metal-organic frameworks, such as organic liquids or ionic species, change the reactivity pathways and kinetics.

  7. Detecting multimodality in saccadic reaction time distributions in gap and overlap tasks.

    Science.gov (United States)

    Gezeck, S; Timmer, J

    1998-04-01

    In many cases the distribution of saccadic reaction times (SRT) deviates considerably from a unimodal distribution and may often exhibit several peaks. We present a statistical approach to determining the number and form of the individual peaks. The overall density of the reaction times fi(t), i = 1...M obtained in M different experiments with the same subject is described as the sum of K basis functions xk(t), k = 1...K with different weights and an error term. A change in the experimental conditions is assumed to cause a change in the weights, not in the basis functions. We minimize the square of the difference (measured data minus approximation), divided by the error of the data. Incrementing K step by step we determine the necessary number of basis functions. This method is applied to data of six subjects tested in different saccade tasks. We detect five different modes: two in the range 80-140 ms (express modes), two in the range 145-190 ms (fast-regular mode) and one at about 230 ms (slow-regular mode). These modes are located at about the same positions for different subjects. The method presented here not only proves statistically the existence of several modes in SRT distributions but also allows the distributions to be described by a few characteristic numbers that go beyond the mean values and standard deviations.

  8. Time-resolved structural studies of protein reaction dynamics: a smorgasbord of X-ray approaches.

    Science.gov (United States)

    Westenhoff, Sebastian; Nazarenko, Elena; Malmerberg, Erik; Davidsson, Jan; Katona, Gergely; Neutze, Richard

    2010-03-01

    Proteins undergo conformational changes during their biological function. As such, a high-resolution structure of a protein's resting conformation provides a starting point for elucidating its reaction mechanism, but provides no direct information concerning the protein's conformational dynamics. Several X-ray methods have been developed to elucidate those conformational changes that occur during a protein's reaction, including time-resolved Laue diffraction and intermediate trapping studies on three-dimensional protein crystals, and time-resolved wide-angle X-ray scattering and X-ray absorption studies on proteins in the solution phase. This review emphasizes the scope and limitations of these complementary experimental approaches when seeking to understand protein conformational dynamics. These methods are illustrated using a limited set of examples including myoglobin and haemoglobin in complex with carbon monoxide, the simple light-driven proton pump bacteriorhodopsin, and the superoxide scavenger superoxide reductase. In conclusion, likely future developments of these methods at synchrotron X-ray sources and the potential impact of emerging X-ray free-electron laser facilities are speculated upon.

  9. Driver contrast sensitivity and reaction times as measured through a salt-covered windshield.

    Science.gov (United States)

    Bachman, W Gary; Wingert, Timothy A; Bassi, Carl J

    2006-02-01

    The objective of this study was to use contrast sensitivity measurements to determine the effect of windshield salt film on driver vision. This effect simulates road salt spray that dries in place on a vehicle windshield during winter driving conditions. Ten emmetropic subjects were tested to assess contrast sensitivity functions through windshields that were clear compared with the same stimuli as viewed through windshields coated with salt film. Achromatic stimuli were generated by a VisionWorks system and were presented at 4 spatial frequencies (0.5, 3, 10, and 20 cycles per degree). A significant reduction in contrast sensitivity through the salt film was found at all spatial frequencies. In addition, reaction time to detect the stimuli was also found to be increased significantly at 2 of the 4 spatial frequencies through the saline-covered windshield. The results of this study indicate that windshield salt film reduces the ability to detect high and low contrast objects in a simulated driving environment as well as increases the subjects' reaction times.

  10. Influence of Shift Work on Manual Dexterity and Reaction Time in Tunisian Nurses.

    Science.gov (United States)

    Merchaoui, Irtyah; Chaari, N; Bouhlel, Mohamed; Bouzgarrou, Lamia; Malchaire, Jacques; Akrout, Mohamed

    2017-10-26

    Major effects of shift schedule are related to sleep alertness and performance , but also to long term health outcomes. For nurses, these negative effects have consequences not only on the individual, but also on the workplace, as decreased alertness and reduced job performance could endanger human lives. The specific aim of our study is to assess the influence of shift schedule on nurses´ cognitive ability and rapidity of execution. Our survey is a cross sectional study which had been conducted for 15 months; it involved a sample of 293 participants representative of 1118 nurses working in two Tunisian university hospitals. It included an evaluation of the rapidity of execution performance through the manual dexterity test and the reaction time test. The study was completed by an assessment of the workability Index through a 7-item survey. No association was found between the groups of work schedules and the cognitive ability of execution speed. However, we found a significant decrease in cognitive performance in the nurses exceeding 10 years of job seniority for both schedules. We concluded to an impaired cognitive performance speed in the over 10-year seniority groups in both schedules. Recommendations should be focused on implementing periodic assessment of cognitive performance based on O'Connor finger dexterity test and time reaction test and on implementing effective preventive measures in hospitals after ten years of seniority at work. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Associations between reaction time measures and white matter hyperintensities in very old age.

    Science.gov (United States)

    Haynes, Becky I; Bunce, David; Kochan, Nicole A; Wen, Wei; Brodaty, Henry; Sachdev, Perminder S

    2017-02-01

    In old age, a relationship has been reported between intraindividual variability (IIV) in reaction time and white matter integrity as evidenced by white matter hyperintensities (WMH). However, it is unclear how far such associations are due to incipient neurodegenerative pathology in the samples investigated. The present study examined the relationship between IIV and WMH in older individuals (N=526) drawn from the Sydney Memory and Ageing Study. Using a complex reaction time (RT) task, greater IIV and mean-RT were related to a higher WMH burden in the frontal lobe. Critically, significant associations remained having taken future dementia into account suggesting that they were not explained by incipient dementia. Additionally, independent measures of executive function accounted for the association between RT metrics and WHM. The results are consistent with the view that frontally-supported cognitive processes are involved in IIV-WMH relations, and that RT measures are sensitive to compromise in white matter structures in non-demented older individuals. Copyright © 2017. Published by Elsevier Ltd.

  12. A Chemical Reaction Network to Generate Random, Power-Law-Distributed Time Intervals.

    Science.gov (United States)

    Krauss, Patrick; Schulze, Holger; Metzner, Claus

    2017-10-06

    In Lévy walks (LWs), particles move with a fixed speed along straight line segments and turn in new directions after random time intervals that are distributed according to a power law. Such LWs are thought to be an advantageous foraging and search strategy for organisms. While complex nervous systems are certainly capable of producing such behavior, it is not clear at present how single-cell organisms can generate the long-term correlated control signals required for a LW. Here, we construct a biochemical reaction system that generates long-time correlated concentration fluctuations of a signaling substance, with a tunable fractional exponent of the autocorrelation function. The network is based on well-known modules, and its basic function is highly robust with respect to the parameter settings.

  13. EEG-Based User Reaction Time Estimation Using Riemannian Geometry Features.

    Science.gov (United States)

    Wu, Dongrui; Lance, Brent J; Lawhern, Vernon J; Gordon, Stephen; Jung, Tzyy-Ping; Lin, Chin-Teng

    2017-11-01

    Riemannian geometry has been successfully used in many brain-computer interface (BCI) classification problems and demonstrated superior performance. In this paper, for the first time, it is applied to BCI regression problems, an important category of BCI applications. More specifically, we propose a new feature extraction approach for electroencephalogram (EEG)-based BCI regression problems: a spatial filter is first used to increase the signal quality of the EEG trials and also to reduce the dimensionality of the covariance matrices, and then Riemannian tangent space features are extracted. We validate the performance of the proposed approach in reaction time estimation from EEG signals measured in a large-scale sustained-attention psychomotor vigilance task, and show that compared with the traditional powerband features, the tangent space features can reduce the root mean square estimation error by 4.30%-8.30%, and increase the estimation correlation coefficient by 6.59%-11.13%.

  14. A solution for measuring accurate reaction time to visual stimuli realized with a programmable microcontroller.

    Science.gov (United States)

    Ohyanagi, Toshio; Sengoku, Yasuhito

    2010-02-01

    This article presents a new solution for measuring accurate reaction time (SMART) to visual stimuli. The SMART is a USB device realized with a Cypress Programmable System-on-Chip (PSoC) mixed-signal array programmable microcontroller. A brief overview of the hardware and firmware of the PSoC is provided, together with the results of three experiments. In Experiment 1, we investigated the timing accuracy of the SMART in measuring reaction time (RT) under different conditions of operating systems (OSs; Windows XP or Vista) and monitor displays (a CRT or an LCD). The results indicated that the timing error in measuring RT by the SMART was less than 2 msec, on average, under all combinations of OS and display and that the SMART was tolerant to jitter and noise. In Experiment 2, we tested the SMART with 8 participants. The results indicated that there was no significant difference among RTs obtained with the SMART under the different conditions of OS and display. In Experiment 3, we used Microsoft (MS) PowerPoint to present visual stimuli on the display. We found no significant difference in RTs obtained using MS DirectX technology versus using the PowerPoint file with the SMART. We are certain that the SMART is a simple and practical solution for measuring RTs accurately. Although there are some restrictions in using the SMART with RT paradigms, the SMART is capable of providing both researchers and health professionals working in clinical settings with new ways of using RT paradigms in their work.

  15. Human short-term exposure to electromagnetic fields emitted by mobile phones decreases computer-assisted visual reaction time.

    Science.gov (United States)

    Mortazavi, S M J; Rouintan, M S; Taeb, S; Dehghan, N; Ghaffarpanah, A A; Sadeghi, Z; Ghafouri, F

    2012-06-01

    The worldwide dramatic increase in mobile phone use has generated great concerns about the detrimental effects of microwave radiations emitted by these communication devices. Reaction time plays a critical role in performing tasks necessary to avoid hazards. As far as we know, this study is the first survey that reports decreased reaction time after exposure to electromagnetic fields generated by a high specific absorption rate mobile phone. It is also the first study in which previous history of mobile phone use is taken into account. The aim of this study was to assess both the acute and chronic effects of electromagnetic fields emitted by mobile phones on reaction time in university students. Visual reaction time (VRT) of young university students was recorded with a simple blind computer-assisted-VRT test, before and after a 10 min real/sham exposure to electromagnetic fields of mobile phones. Participants were 160 right-handed university students aged 18-31. To assess the effect of chronic exposures, the reaction time in sham-exposed phases were compared among low level, moderate and frequent users of mobile phones. The mean ± SD reaction time after real exposure and sham exposure were 286.78 ± 31.35 ms and 295.86 ± 32.17 ms (P reaction time either in talk or in standby mode. The reaction time either in talk or in standby mode was shorter in male students. The students' VRT was significantly affected by exposure to electromagnetic fields emitted by a mobile phone. It can be concluded that these exposures cause decreased reaction time, which may lead to a better response to different hazards. In this light, this phenomenon might decrease the chances of human errors and fatal accidents.

  16. Cold-Curing Structural Epoxy Resins: Analysis of the Curing Reaction as a Function of Curing Time and Thickness.

    Science.gov (United States)

    Corcione, Carola Esposito; Freuli, Fabrizio; Frigione, Mariaenrica

    2014-09-22

    The curing reaction of a commercial cold-curing structural epoxy resin, specifically formulated for civil engineering applications, was analyzed by thermal analysis as a function of the curing time and the sample thickness. Original and remarkable results regarding the effects of curing time on the glass transition temperature and on the residual heat of reaction of the cold-cured epoxy were obtained. The influence of the sample thickness on the curing reaction of the cold-cured resin was also deeply investigated. A highly exothermal reaction, based on a self-activated frontal polymerization reaction, was supposed and verified trough a suitable temperature signal acquisition system, specifically realized for this measurement. This is one of the first studies carried out on the curing behavior of these peculiar cold-cured epoxy resins as a function of curing time and thickness.

  17. A New Approach and Solution Technique to Solve Time Fractional Nonlinear Reaction-Diffusion Equations

    Directory of Open Access Journals (Sweden)

    Inci Cilingir Sungu

    2015-01-01

    Full Text Available A new application of the hybrid generalized differential transform and finite difference method is proposed by solving time fractional nonlinear reaction-diffusion equations. This method is a combination of the multi-time-stepping temporal generalized differential transform and the spatial finite difference methods. The procedure first converts the time-evolutionary equations into Poisson equations which are then solved using the central difference method. The temporal differential transform method as used in the paper takes care of stability and the finite difference method on the resulting equation results in a system of diagonally dominant linear algebraic equations. The Gauss-Seidel iterative procedure then used to solve the linear system thus has assured convergence. To have optimized convergence rate, numerical experiments were done by using a combination of factors involving multi-time-stepping, spatial step size, and degree of the polynomial fit in time. It is shown that the hybrid technique is reliable, accurate, and easy to apply.

  18. Multiplexed real-time polymerase chain reaction on a digital microfluidic platform.

    Science.gov (United States)

    Hua, Zhishan; Rouse, Jeremy L; Eckhardt, Allen E; Srinivasan, Vijay; Pamula, Vamsee K; Schell, Wiley A; Benton, Jonathan L; Mitchell, Thomas G; Pollack, Michael G

    2010-03-15

    This paper details the development of a digital microfluidic platform for multiplexed real-time polymerase chain reactions (PCR). Liquid samples in discrete droplet format are programmably manipulated upon an electrode array by the use of electrowetting. Rapid PCR thermocycling is performed in a closed-loop flow-through format where for each cycle the reaction droplets are cyclically transported between different temperature zones within an oil-filled cartridge. The cartridge is fabricated using low-cost printed-circuit-board technology and is intended to be a single-use disposable device. The PCR system exhibited remarkable amplification efficiency of 94.7%. To test its potential application in infectious diseases, this novel PCR system reliably detected diagnostic DNA levels of methicillin-resistant Staphylococcus aureus (MRSA), Mycoplasma pneumoniae , and Candida albicans . Amplification of genomic DNA samples was consistently repeatable across multiple PCR loops both within and between cartridges. In addition, simultaneous real-time PCR amplification of both multiple different samples and multiple different targets on a single cartridge was demonstrated. A novel method of PCR speed optimization using variable cycle times has also been proposed and proven feasible. The versatile system includes magnetic bead handling capability, which was applied to the analysis of simulated clinical samples that were prepared from whole blood using a magnetic bead capture protocol. Other salient features of this versatile digital microfluidic PCR system are also discussed, including the configurability and scalability of microfluidic operations, instrument portability, and substrate-level integration with other pre- and post-PCR processes.

  19. Intraindividual variability in reaction time before and after neoadjuvant chemotherapy in women diagnosed with breast cancer.

    Science.gov (United States)

    Yao, Christie; Rich, Jill B; Tirona, Kattleya; Bernstein, Lori J

    2017-12-01

    Women treated with chemotherapy for breast cancer experience subtle cognitive deficits. Research has focused on mean performance level, yet recent work suggests that within-person variability in reaction time performance may underlie cognitive symptoms. We examined intraindividual variability (IIV) in women diagnosed with breast cancer and treated with neoadjuvant chemotherapy. Patients (n = 28) were assessed at baseline before chemotherapy (T1), approximately 1 month after chemotherapy but prior to surgery (T2), and after surgery about 9 months post chemotherapy (T3). Healthy women of similar age and education (n = 20) were assessed at comparable time intervals. Using a standardized regression-based approach, we examined changes in mean performance level and IIV (eg, intraindividual standard deviation) on a Stroop task and self-report measures of cognitive function from T1 to T2 and T1 to T3. At T1, women with breast cancer were more variable than controls as task complexity increased. Change scores from T1 to T2 were similar between groups on all Stroop performance measures. From T1 to T3, controls improved more than women with breast cancer. IIV was more sensitive than mean reaction time in capturing group differences. Additional analyses showed increased cognitive symptoms reported by women with breast cancer from T1 to T3. Specifically, change in language symptoms was positively correlated with change in variability. Women with breast cancer declined in attention and inhibitory control relative to pretreatment performance. Future studies should include measures of variability, because they are an important sensitive indicator of change in cognitive function. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Ramadan fasting does not adversely affect neuromuscular performances and reaction times in trained karate athletes.

    Science.gov (United States)

    Zarrouk, Nidhal; Hammouda, Omar; Latiri, Imed; Adala, Hela; Bouhlel, Ezzedine; Rebai, Haithem; Dogui, Mohamed

    2016-01-01

    The present study aimed to investigate the concomitant effects of Ramadan intermittent fast (RIF) and muscle fatigue on neuromuscular performances and reaction times in young trained athletes. Eight karate players (17.2 ± 0.5 years) were tested on three sessions: during a control period (S1: one week before Ramadan), and during the first (S2) and the fourth week of RIF (S3). Dietary intake and anthropometric measurements were assessed before each session. During each test session, participants performed maximal voluntary isometric contractions (MVC) and a submaximal contraction at 75 % MVC until exhaustion (T lim ) of the right elbow flexors. Surface electromyography was recorded from biceps brachii muscle during MVC and T lim . Simple (SRT) and choice (CRT) reaction times were evaluated at rest and just after T lim in a random order. The total daily energy (S2: +19.5 %, p < 0.05; S3: +27.4 %, p < 0.01) and water (S2: +26.8 %, p < 0.01; S3: +23.2 %, p < 0.05) intake were significantly increased during RIF. However, neither body mass nor body mass index was altered by RIF (F (2,14) = 0.80, p = 0.47 and F (2,14) = 0.78, p = 0.48, respectively). In addition, T lim (F (2,14) = 2.53, p = 0.12), MVC (F (2,14) = 0.51, p = 0.61) and associated electrical activity (F (2,14) = 0.13, p = 0.88) as well as neuromuscular efficiency (F (2,14) = 0.27, p = 0.76) were maintained during RIF. Moreover, neither SRT nor CRT was affected by RIF (F (2,14) = 1.82, p = 0.19 and F (2,14) = 0.26, p = 0.78, respectively) or neuromuscular fatigue (F (1,7) = 0.0002, p = 0.98 and F (1,7) = 3.78, p = 0.09, respectively). The present results showed that RIF did not adversely affect the neuromuscular performances and anthropometric parameters of elite karate athletes who were undertaking their usual training schedule. In addition, neither RIF nor neuromuscular fatigue poorly affects reaction

  1. Validating the Accuracy of Reaction Time Assessment on Computer-Based Tablet Devices.

    Science.gov (United States)

    Schatz, Philip; Ybarra, Vincent; Leitner, Donald

    2015-08-01

    Computer-based assessment has evolved to tablet-based devices. Despite the availability of tablets and "apps," there is limited research validating their use. We documented timing delays between stimulus presentation and (simulated) touch response on iOS devices (3rd- and 4th-generation Apple iPads) and Android devices (Kindle Fire, Google Nexus, Samsung Galaxy) at response intervals of 100, 250, 500, and 1,000 milliseconds (ms). Results showed significantly greater timing error on Google Nexus and Samsung tablets (81-97 ms), than Kindle Fire and Apple iPads (27-33 ms). Within Apple devices, iOS 7 obtained significantly lower timing error than iOS 6. Simple reaction time (RT) trials (250 ms) on tablet devices represent 12% to 40% error (30-100 ms), depending on the device, which decreases considerably for choice RT trials (3-5% error at 1,000 ms). Results raise implications for using the same device for serial clinical assessment of RT using tablets, as well as the need for calibration of software and hardware. © The Author(s) 2015.

  2. Real-time polymerase chain reaction for detection of Strongyloides stercoralis in stool.

    Science.gov (United States)

    Sultana, Yasmin; Jeoffreys, Neisha; Watts, Matthew R; Gilbert, Gwendolyn L; Lee, Rogan

    2013-06-01

    The use of real-time polymerase chain reaction (PCR) for detection of Strongyloides stercoralis in stool has recently been described. We compared five DNA extraction methods by using normal human stool spiked with Strongyloides ratti and tested by using a real-time PCR. The PowerSoil kit was found to be the best technique in terms of sensitivity and ease of use. The PCR detected DNA extracted from one spiked S. ratti larva diluted 10⁻². The PowerSoil kit was then used to extract DNA from 160 human survey samples. All culture positive specimens with a high and moderate larval load were identified by real-time PCR, but only 15% of specimens with low larval load were positive. Specificity was greater than 99%. The combination of the PowerSoil kit and real-time PCR reliably detected high to moderate larval numbers of S. stercoralis in stools but was less sensitive when the larval load was low.

  3. Development of a real time polymerase chain reaction for quantitation of Schistosoma mansoni DNA

    Directory of Open Access Journals (Sweden)

    Ana Lisa do Vale Gomes

    2006-10-01

    Full Text Available This report describes the development of a SYBR Green I based real time polymerase chain reaction (PCR protocol for detection on the ABI Prism 7000 instrument. Primers targeting the gene encoding the SSU rRNA were designed to amplify with high specificity DNA from Schistosoma mansoni, in a real time quantitative PCR system. The limit of detection of parasite DNA for the system was 10 fg of purified genomic DNA, that means less than the equivalent to one parasite cell (genome ~580 fg DNA. The efficiency was 0.99 and the correlation coefficient (R² was 0.97. When different copy numbers of the target amplicon were used as standards, the assay could detect at least 10 copies of the specific target. The primers used were designed to amplify a 106 bp DNA fragment (Tm 83ºC. The assay was highly specific for S. mansoni, and did not recognize DNA from closely related non-schistosome trematodes. The real time PCR allowed for accurate quantification of S. mansoni DNA and no time-consuming post-PCR detection of amplification products by gel electrophoresis was required. The assay is potentially able to quantify S. mansoni DNA (and indirectly parasite burden in a number of samples, such as snail tissue, serum and feces from patients, and cercaria infested water. Thus, these PCR protocols have potential to be used as tools for monitoring of schistosome transmission and quantitative diagnosis of human infection.

  4. Changes in Choice Reaction Time During and After 8 Days Exhaustive Cycling are not Related to Changes in Physical Performance.

    Science.gov (United States)

    Ten Haaf, Twan; van Staveren, Selma; Iannetta, Danilo; Roelands, Bart; Meeusen, Romain; Piacentini, Maria F; Foster, Carl; Koenderman, Leo; Daanen, Hein A M; de Koning, Jos J

    2017-09-05

    Reaction time has been proposed as a training monitoring tool, but to date results are equivocal. Therefore, it was investigated whether reaction time can be used as a monitoring tool to establish overreaching. The study included 30 subjects (11 female/19 male, age: 40.8±10.8 y, VO2max: 51.8±6.3 ml/kg/min) who participated in an 8-day cycling event. The external exercise load increased approximately 900% compared to the preparation period. Performance was measured before and after the event using a maximal incremental cycling test. Subjects with decreased performance after the event were classified as functionally overreached (FOR), others as acutely fatigued (AF). A choice reaction time test was performed 2 weeks before (pre), 1 week after (post) and 5 weeks after (follow-up), as well as at the start and end of the event. Fourteen subjects were classified as AF and 14 as FOR (2 subjects were excluded). During the event, reaction time at the end was 68 ms (95% CI [46, 89]) faster than at the start. Reaction time post event was 41 ms (95% CI [12, 71]) faster than pre, and follow-up 55 ms faster (95% CI [26, 83]). The time by class interaction was not significant during (p=.26) and after (p=.43) the event. Correlations between physical performance and reaction time were not significant (all p>.30). No differences in choice reaction time between AF and FOR subjects were observed. It is suggested that choice reaction time is not valid for early detection of overreaching in the field.

  5. Neck-shortening effect on prosaccade reaction time formed through saccadic training accompanied by maintenance of neck flexion.

    Science.gov (United States)

    Kunita, Kenji; Fujiwara, Katsuo

    2009-11-01

    We investigated the effect of neck-shortening on prosaccade reaction time formed through saccadic training accompanied by maintenance of neck flexion. The subjects were 30 university students who exhibited no significant shortening of prosaccade reaction time during maintenance of neck flexion, assigned to three groups: prosaccade training subjects at rest neck position (rest training group); prosaccade training subjects at 20 degrees neck flexion position (neck training group); and untrained subjects (control group). Saccadic training for 1 min was performed ten times per day, and the training period was 14 days. For the control group, no significant postural or training effects on reaction time were found. For both training groups, reaction time at the rest position after training was significantly shorter than that before training. For the neck training group, reaction time after training was significantly shorter at the neck flexion position than at the rest position. Conversely, no significant neck effect was found for the rest training group. This indicates that the shortening effect associated with maintenance of neck flexion on prosaccade reaction time is formed through saccadic training accompanied by maintenance of neck flexion.

  6. Effects of morning caffeine' ingestion on mood States, simple reaction time, and short-term maximal performance on elite judoists

    National Research Council Canada - National Science Library

    Souissi, Makram; Abedelmalek, Salma; Chtourou, Hamdi; Atheymen, Rim; Hakim, Ahmed; Sahnoun, Zouhair

    2012-01-01

    The purpose of the present study was to evaluate the ergogenic effect of caffeine ingestion on mood state, simple reaction time, and muscle power during the Wingate test recorded in the morning on elite Judoists...

  7. The effects of arm movement on reaction time in patients with latent and active upper trapezius myofascial trigger point

    National Research Council Canada - National Science Library

    Yassin, Marzieh; Talebian, Saeed; Ebrahimi Takamjani, Ismail; Maroufi, Nader; Ahmadi, Amir; Sarrafzadeh, Javad; Emrani, Anita

    2015-01-01

    Myofascial pain syndrome is a significant source of mechanical pain. The aim of this study was to investigate the effects of arm movement on reaction time in females with latent and active upper trapezius myofascial trigger point...

  8. Study of Auditory, Visual Reaction Time and Glycemic Control (HBA1C) in Chronic Type II Diabetes Mellitus

    OpenAIRE

    M, Muhil; Sembian, Umapathy; Babitha,; N, Ethiya; K, Muthuselvi

    2014-01-01

    Background: Diabetes mellitus is a disease of insulin deficiencyleads to micro and macro vascular disorder. Neuropathy is one of the major complication of chronic uncontrolled Diabetes affecting the Reaction time.

  9. Sustained attention is associated with error processing impairment: evidence from mental fatigue study in four-choice reaction time task

    National Research Council Canada - National Science Library

    Xiao, Yi; Ma, Feng; Lv, Yixuan; Cai, Gui; Teng, Peng; Xu, FengGang; Chen, Shanguang

    2015-01-01

    .... In this study, we examined how error-related negativity (ERN) of a four-choice reaction time task was reduced in the mental fatigue condition and investigated the role of sustained attention in error processing...

  10. A robot for verifying the precision of total reaction time measurement

    Directory of Open Access Journals (Sweden)

    Tânia Brusque Crocetta

    2015-03-01

    Full Text Available The level of variability in psychomotor behavior and the use of several distinct sets of equipments in Reaction Time (RT assessments might jeopardize the validity and reliability of such measures. This study presents the development and verification of Emboici Robot-a robot capable of performing accurate RT assessments consisting of response to a visual stimulus by pressing a button-whose purpose is to measure the accuracy of RT assessments. We evaluated the accuracy and precision on four different days, each providing 300 measurements. These assessments generated a RT of 46.95ms (+6.04. No significant effects were found in the RTs obtained and, as a result, there is evidence that the Emboici Robotis stable, reliable, and precise. The robot can be a viable solution for verifying precision and accuracy of any given software with simple RT assessments with visual stimulus requiring as response the pressing of a button or key.

  11. Placebo response to caffeine improves reaction time performance in sleepy people.

    Science.gov (United States)

    Anderson, Clare; Horne, James A

    2008-06-01

    Caffeine is the most widely used stimulant to counteract sleepiness. However, little is known about any placebo effect of caffeine in sleepy people and the effect of suggestibility. Over a 95 min test period, and in a counterbalanced design, 16 young healthy adults underwent 3 x 30 min sessions at the psychomotor vigilance test (PVT), during an early afternoon 'dip' enhanced by a prior night's sleep restriction (5 h). On both occasions they were given a cup of a decaffeinated coffee; once when the participant was verbally primed to suggest the coffee was caffeinated (Placebo) and on the other under neutral priming (Control). There were significantly fewer lapses and shorter reaction times following Placebo, for the initial two 30 min sessions, indicating that suggestion about consuming caffeine was effective in improving performance in moderately sleepy people. (c) 2008 John Wiley & Sons, Ltd.

  12. Adobe Flash as a medium for online experimentation: a test of reaction time measurement capabilities.

    Science.gov (United States)

    Reimers, Stian; Stewart, Neil

    2007-08-01

    Adobe Flash can be used to run complex psychological experiments over the Web. We examined the reliability of using Flash to measure reaction times (RTs) using a simple binary-choice task implemented both in Flash and in a Linux-based system known to record RTs with millisecond accuracy. Twenty-four participants were tested in the laboratory using both implementations; they also completed the Flash version on computers of their own choice outside the lab. RTs from the trials run on Flash outside the lab were approximately 20 msec slower than those from trials run on Flash in the lab, which in turn were approximately 10 msec slower than RTs from the trials run on the Linux-based system (baseline condition). RT SDs were similar in all conditions, suggesting that although Flash may overestimate RTs slightly, it does not appear to add significant noise to the data recorded.

  13. Wavefronts in time-delayed reaction-diffusion systems. Theory and comparison to experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fort, Joaquim [Departament de Fisica, Universitat de Girona, Girona (Spain)]. E-mail: joaquim.fort@udg.es; Mendez, Vicenc [Facultat de Ciencies de la Salut, Universitat Internacional de Catalunya, Ssant Cugat del Valles (Spain)]. E-mail: vmendez@csc.unica.edu

    2002-06-01

    We review the recent theoretical progress in the formulation and solution of the front speed problem for time-delayed reaction-diffusion systems. Most of the review is focused on hyperbolic equations. They have been widely used in recent years, because they allow for analytical solutions and yield a realistic description of some relevant phenomena. The theoretical methods are applied to a range of applications, including population dynamics, forest fire models, bistable systems and combustion wavefronts. We also present a detailed account of successful predictions of the models, as assessed by comparison to experimental data for some biophysical systems, without making use of any free parameters. Areas where the work reviewed may contribute to future progress are discussed. (author)

  14. Action Video Games Improve Direction Discrimination of Parafoveal Translational Global Motion but Not Reaction Times.

    Science.gov (United States)

    Pavan, Andrea; Boyce, Matthew; Ghin, Filippo

    2016-10-01

    Playing action video games enhances visual motion perception. However, there is psychophysical evidence that action video games do not improve motion sensitivity for translational global moving patterns presented in fovea. This study investigates global motion perception in action video game players and compares their performance to that of non-action video game players and non-video game players. Stimuli were random dot kinematograms presented in the parafovea. Observers discriminated the motion direction of a target random dot kinematogram presented in one of the four visual quadrants. Action video game players showed lower motion coherence thresholds than the other groups. However, when the task was performed at threshold, we did not find differences between groups in terms of distributions of reaction times. These results suggest that action video games improve visual motion sensitivity in the near periphery of the visual field, rather than speed response. © The Author(s) 2016.

  15. Chunking by colors: assessing discrete learning in a continuous serial reaction-time task.

    Science.gov (United States)

    Jiménez, Luis; Méndez, Amavia; Pasquali, Antoine; Abrahamse, Elger; Verwey, Willem

    2011-07-01

    Chunk learning (the process by which a sequence is learned and retrieved from memory in smaller, decomposed units of information) has been postulated as the main learning mechanism underlying sequence learning (Perruchet & Pacton, 2006). However, the evidence for chunk formation has been elusive in the continuous serial reaction-time task, whereas other continuous, statistical processes of learning account well for the results observed in this task. This article proposes a new index to capture segmentation in learning, based on the variance of responding to different parts of a sequence. We assess the validity of this measure by comparing performance in a control group with that of another group in which color codes were used to induce a uniform segmentation. Results showed that evidence of chunking was obtained when the color codes were consistently coupled to responses, but that chunking was not maintained after the colors were removed. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Critical flicker frequency and continuous reaction times for the diagnosis of minimal hepatic encephalopathy

    DEFF Research Database (Denmark)

    Lauridsen, Mette Enok Munk; Jepsen, Peter; Vilstrup, Hendrik

    2011-01-01

    Abstract Minimal hepatic encephalopathy (MHE) is intermittently present in up to 2/3 of patients with chronic liver disease. It impairs their daily living and can be treated. However, there is no consensus on diagnostic criteria except that psychometric methods are required. We compared two easy......-to-perform reproducible bedside methods: the critical flicker frequency (CFF) and continuous reaction times (CRT) tests. A CFF disease with out overt hepatic.......005). The two tests were weakly linearly correlated (r(2) = 0.14, p metabolic liver function measured by the Galactose Elimination Capacity (GEC), nor with the blood ammonia concentration. Both tests identified a large fraction of the patients as having MHE...

  17. Reaction time and efficiency of the goalball player in interception/ defense of throwing/attack

    Directory of Open Access Journals (Sweden)

    Gilberto Pereira da Silva

    2010-12-01

    Full Text Available Goalball is a team sport designed for the blind and the visually impaired. This research aimed at analyzing the motor behavior of goalball players in order to evaluate the influence of reaction time (TR in the efficiency of defense actions. Nine athletes from the national team of goalball, who played in the 3rd World Games of IBSA (São Caetano do Sul/SP, August 2007, participated in this study. Data were collected through cinemetry in order to obtain images of motor movements during defense actions and then analyzed and developed using the biomechanics model of motor control of human movements, and treated using a software specific for analyzing movement, the DgeeMe Version 1.0b. Participants' TR met the standard mentioned in the literature. Repetition of movements and promptness to act influenced the quality of their responses and facilitated a decrease in TR.

  18. Reaction time and efficiency of the goalball player in interception/defense of throwing/attack

    Directory of Open Access Journals (Sweden)

    J.I. Gorla

    2010-01-01

    Full Text Available Goalball is a team sport designed for the blind and the visually impaired. This research aimed at analyzing the motor behavior of goalball players in order to evaluate the influence of reaction time (TR in the efficiency of defense actions. Nine athletes from the national team of goalball, who played in the 3rd World Games of IBSA (São Caetano do Sul/SP, August 2007, participated in this study. Data were collected through cinemetry in order to obtain images of motor movements during defense actions and then analyzed and developed using the biomechanics model of motor control of human movements, and treated using a software specific for analyzing movement, the DgeeMe Version 1.0b. Participants' TR met the standard mentioned in the literature. Repetition of movements and promptness to act influenced the quality of their responses and facilitated a decrease in TR.

  19. Determination of SFC, FFA, and equivalent reaction time for enzymatically interestified oils using NIRS

    DEFF Research Database (Denmark)

    Houmøller, Lars P.; Kristensen, Dorthe; Rosager, Helle

    2007-01-01

    The use of near infrared spectroscopy (NIRS) for rapid determination of the degree of interesterification of blends of palm stearin, coconut oil, and rapeseed oil obtained using an immobilized Thermomyces lanuginosa lipase at 70 ◦C was investigated. Interesterification was carried out by applying...... that NIRS could be used to replace the traditional methods for determining FFA and SFC in vegetable oils.It was possible to monitor the activity of the immobilized enzyme for interesterification of margarine oils by predicting the equivalent reaction time in a batch reactor from NIR spectra. Root mean...... square errors of prediction for two different oil blends interesterified for 300 and 170 min were 21 and 12 min, respectively....

  20. Cybersickness provoked by head-mounted display affects cutaneous vascular tone, heart rate and reaction time.

    Science.gov (United States)

    Nalivaiko, Eugene; Davis, Simon L; Blackmore, Karen L; Vakulin, Andrew; Nesbitt, Keith V

    2015-11-01

    Evidence from studies of provocative motion indicates that motion sickness is tightly linked to the disturbances of thermoregulation. The major aim of the current study was to determine whether provocative visual stimuli (immersion into the virtual reality simulating rides on a rollercoaster) affect skin temperature that reflects thermoregulatory cutaneous responses, and to test whether such stimuli alter cognitive functions. In 26 healthy young volunteers wearing head-mounted display (Oculus Rift), simulated rides consistently provoked vection and nausea, with a significant difference between the two versions of simulation software (Parrot Coaster and Helix). Basal finger temperature had bimodal distribution, with low-temperature group (n=8) having values of 23-29 °C, and high-temperature group (n=18) having values of 32-36 °C. Effects of cybersickness on finger temperature depended on the basal level of this variable: in subjects from former group it raised by 3-4 °C, while in most subjects from the latter group it either did not change or transiently reduced by 1.5-2 °C. There was no correlation between the magnitude of changes in the finger temperature and nausea score at the end of simulated ride. Provocative visual stimulation caused prolongation of simple reaction time by 20-50 ms; this increase closely correlated with the subjective rating of nausea. Lastly, in subjects who experienced pronounced nausea, heart rate was elevated. We conclude that cybersickness is associated with changes in cutaneous thermoregulatory vascular tone; this further supports the idea of a tight link between motion sickness and thermoregulation. Cybersickness-induced prolongation of reaction time raises obvious concerns regarding the safety of this technology. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Mood induction effects on motor sequence learning and stop signal reaction time.

    Science.gov (United States)

    Greeley, Brian; Seidler, Rachael D

    2017-01-01

    The neurobiological theory of positive affect proposes that positive mood states may benefit cognitive performance due to an increase of dopamine throughout the brain. However, the results of many positive affect studies are inconsistent; this may be due to individual differences. The relationship between dopamine and performance is not linear, but instead follows an inverted "U" shape. Given this, we hypothesized that individuals with high working memory capacity, a proxy measure for dopaminergic transmission, would not benefit from positive mood induction and in fact performance in dopamine-mediated tasks would decline. In contrast, we predicted that individuals with low working memory capacities would receive the most benefit after positive mood induction. Here, we explored the effect of positive affect on two dopamine-mediated tasks, an explicit serial reaction time sequence learning task and the stop signal task, predicting that an individual's performance is modulated not only by working memory capacity, but also on the type of mood. Improvements in explicit sequence learning from pre- to post-positive mood induction were associated with working memory capacity; performance declined in individuals with higher working memory capacities following positive mood induction, but improved in individuals with lower working memory capacities. This was not the case for negative or neutral mood induction. Moreover, there was no relationship between the change in stop signal reaction time with any of the mood inductions and individual differences in working memory capacity. These results provide partial support for the neurobiological theory of positive affect and highlight the importance of taking into account individual differences in working memory when examining the effects of positive mood induction.

  2. Cell phone ringtone, but not landline phone ringtone, affects complex reaction time

    Directory of Open Access Journals (Sweden)

    Radosław Zajdel

    2013-02-01

    Full Text Available Introduction: Legislation systems of most countries prohibited using the handheld mobile phone while driving due to the fact that it disturbs concentration and causes hand involvement. Every phone owner is accustomed to the ringtone of his phone and almost involuntarily endeavors to pick it up or check who calls. This engages one’s psychomotor skills, which in our opinion contributes to the attenuation of reaction time needed for performing other crucial functions. Objectives: The aim of the study was: (1 to evaluate the infl uence of the sound of a ringing mobile phone on the complex reaction time (RT score in healthy subjects (owners, and (2 to check if there are any differences in RT when a landline phone and mobile phone ring. Methods: To assess RT we used our system and protocol of examination, previously validated. The examination conditions were standardized. All tests were performed in the same room with the same light and general acoustic conditions. The test group consisted of 23 women and 24 men, aged 19–24 years. The examination comprised 4 sessions: Training Session (TS during which the subjects were accustomed with the application and sample stimuli, Control Session (CS with no telephone ringing, Landline Session (LS with landline phone ringing, Mobile Session (MS with mobile phone ringing. Results: The median RT in the study population was signifi cantly elongated (p 0.05. Conclusions: We think that the specifi c ‘bond’ between a person and their private phone can signifi cantly disrupt their attention and thus affect the attention-demanding activities.

  3. Effects of prefrontal anodal transcranial direct current stimulation on working-memory and reaction time.

    Science.gov (United States)

    Verissimo, Ines S; Barradas, Isabel M; Santos, Tiago T; Miranda, Pedro C; Ferreira, Hugo A

    2016-08-01

    Transcranial direct current stimulation (tDCS) has proven to be a useful tool in the scientific research community, particularly for clinical investigation purposes. Neuroimaging studies indicate that there is a connection between the prefrontal cortex (PFC) and working memory (WM), as well as between the primary motor cortex and reaction time (RT). Thus, our goal was to evaluate the effect of anodal stimulation of the PFC, with respect to WM and RT. We tested 20 healthy subjects randomized into two groups - half received active stimulation and the other half sham stimulation. Participants underwent two stimulation sessions of 10 minutes each, separated by a 10-minute interval for rest. The task was performed during the stimulation periods, and consisted in the display of a list of words for the subject to read and memorize. Afterwards, a new list was shown and the subject was asked to to press a key when a repeated word appeared. A current of 1 mA was delivered via a foc.us gamer headset. After both stimulations, the participants answered an Adverse Effects Questionnaire. Statistical tests were performed to compare the accuracy, error rate, and reaction time values for active vs. sham and first vs. second stimulations. The results obtained led us to infer that there were no significant improvements in the performance of the active group in comparison with the sham group, in terms of WM and overall RT values. However, RT data analysis indicated that active simulation subjects showed significantly lower values when compared to the sham group, only for the first stimulation period. Due to emerging technological advances, the videogame industry has started to invest in the commercialization of products that promise to enhance neural functions and, thus, improve gamers' performance. The results obtained provide evidence of the importance of testing such commercial devices. The scientific community should have an active role in the validation of these claims.

  4. Study of gas-phase reactions of NO2+ with aromatic compounds using proton transfer reaction time-of-flight mass spectrometry.

    Science.gov (United States)

    Li, Jianquan; Du, Xubing; Guo, Teng; Peng, Zhen; Xu, Li; Dong, Junguo; Cheng, Ping; Zhou, Zhen

    2017-12-01

    The study of ion chemistry involving the NO2+ is currently the focus of considerable fundamental interest and is relevant in diverse fields ranging from mechanistic organic chemistry to atmospheric chemistry. A very intense source of NO2+ was generated by injecting the products from the dielectric barrier discharge of a nitrogen and oxygen mixture upstream into the drift tube of a proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) apparatus with H3 O+ as the reagent ion. The NO2+ intensity is controllable and related to the dielectric barrier discharge operation conditions and ratio of oxygen to nitrogen. The purity of NO2+ can reach more than 99% after optimization. Using NO2+ as the chemical reagent ion, the gas-phase reactions of NO2+ with 11 aromatic compounds were studied by PTR-TOF-MS. The reaction rate coefficients for these reactions were measured, and the product ions and their formation mechanisms were analyzed. All the samples reacted with NO2+ rapidly with reaction rate coefficients being close to the corresponding capture ones. In addition to electron transfer producing [M]+ , oxygen ion transfer forming [MO]+ , and 3-body association forming [M·NO2 ]+ , a new product ion [M-C]+ was also formed owing to the loss of C═O from [MO]+ .This work not only developed a new chemical reagent ion NO2+ based on PTR-MS but also provided significant interesting fundamental data on reactions involving aromatic compounds, which will probably broaden the applications of PTR-MS to measure these compounds in the atmosphere in real time. Copyright © 2017 John Wiley & Sons, Ltd.

  5. Diagnosis of neonatal sepsis by broad-range 16S real-time polymerase chain reaction.

    Science.gov (United States)

    Ohlin, Andreas; Bäckman, Anders; Ewald, Uwe; Schollin, Jens; Björkqvist, Maria

    2012-01-01

    The standard diagnostic test (blood culture) for suspected neonatal sepsis has limitations in sensitivity and specificity, and 16S polymerase chain reaction (PCR) has been suggested as a new diagnostic tool for neonatal sepsis. To develop and evaluate a new real-time PCR method for detection of bacterial DNA in blood samples collected from infants with suspected neonatal sepsis. Immediately after blood culture, a study sample of 0.5-1.0 ml whole blood was collected and used for a novel 16S real-time PCR assay. All positive samples were sequenced. Detailed case studies were performed in all cases with conflicting results, to verify if PCR could detect pathogens in culture negative sepsis. 368 samples from 317 infants were included. When compared with blood culture, the assay yielded a sensitivity of 79%, a specificity of 90%, a positive predictive value of 59%, and a negative predictive value of 96%. Seven of the 31 samples with a positive PCR result and a negative blood culture had definite or suspected bacterial sepsis. In five samples, PCR (but not blood culture) could detect a pathogen that was present in a blood culture collected more than 24 h prior to the PCR sample. This study presents an evaluation of a new real-time PCR technique that can detect culture-positive sepsis, and suggests that PCR has the potential to detect bacteria in culture-negative samples even after the initiation of intravenous antibiotics. Copyright © 2011 S. Karger AG, Basel.

  6. Temporal predictive mechanisms modulate motor reaction time during initiation and inhibition of speech and hand movement.

    Science.gov (United States)

    Johari, Karim; Behroozmand, Roozbeh

    2017-08-01

    Skilled movement is mediated by motor commands executed with extremely fine temporal precision. The question of how the brain incorporates temporal information to perform motor actions has remained unanswered. This study investigated the effect of stimulus temporal predictability on response timing of speech and hand movement. Subjects performed a randomized vowel vocalization or button press task in two counterbalanced blocks in response to temporally-predictable and unpredictable visual cues. Results indicated that speech and hand reaction time was decreased for predictable compared with unpredictable stimuli. This finding suggests that a temporal predictive code is established to capture temporal dynamics of sensory cues in order to produce faster movements in responses to predictable stimuli. In addition, results revealed a main effect of modality, indicating faster hand movement compared with speech. We suggest that this effect is accounted for by the inherent complexity of speech production compared with hand movement. Lastly, we found that movement inhibition was faster than initiation for both hand and speech, suggesting that movement initiation requires a longer processing time to coordinate activities across multiple regions in the brain. These findings provide new insights into the mechanisms of temporal information processing during initiation and inhibition of speech and hand movement. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Reaction Time is a Marker of Early Cognitive and Behavioral Alterations in Pure Cerebral Small Vessel Disease.

    Science.gov (United States)

    Jouvent, Eric; Reyes, Sonia; De Guio, François; Chabriat, Hugues

    2015-01-01

    The assessment of early and subtle cognitive and behavioral effects of cerebral small vessel disease (SVD) requires specific and long-lasting evaluations performed by experienced neuropsychologists. Simpler tools would be helpful for daily clinical practice. To determine whether a simple reaction time task that lasts 5 minutes and can be performed without external supervision on any tablet or laptop can be used as a proxy of early cognitive and behavioral alterations in CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), a monogenic form of pure SVD related to NOTCH3 mutations. Twenty-two genetically confirmed patients with CADASIL having preserved global cognitive abilities and without disability (MMSE >24 and modified Rankin's scale ≤1) were compared to 29 age-and-gender matched controls to determine group differences according to: 1) conventional neuropsychological and behavioral testing; 2) a computerized battery evaluating reaction time, processing speed, and executive functions. In a second step, correlations between reaction time and cognitive and behavioral alterations detected using both conventional and computerized testing were tested in patients. Reaction time was significantly higher in patients than in controls (mean in patients: 283 ms - in controls: 254 ms, p = 0.03). In patients, reaction time was significantly associated with conventional and chronometric tests of executive functions, working memory, and apathy. Reaction time obtained using a very simple task may serve as a proxy of early cognitive and behavioral alterations in SVD and could be easily used in daily clinical practice.

  8. Attention-Deficit/Hyperactivity Disorder (ADHD) and Motor Timing in Adolescents and Their Parents : Familial Characteristics of Reaction Time Variability Vary With Age

    NARCIS (Netherlands)

    Thissen, Andrieke J. A. M.; Luman, Marjolein; Hartman, Catharina; Hoekstra, Pieter; van Lieshout, Marloes; Franke, Barbara; Oosterlaan, Jaap; Rommelse, Nanda N. J.; Buitelaar, Jan K.

    Objective: There is consistent evidence that attention-deficit/hyperactivity disorder (ADHD) is strongly related to impaired motor timing as reflected in decreased accuracy and increased reaction time variability (RTV). It is not known whether motor timing impairments are present in adolescents and

  9. Development and application of a real-time polymerase chain reaction method for Campylobacter jejuni detection.

    Science.gov (United States)

    Zhang, Mao-Jun; Qiao, Bo; Xu, Xue-Bin; Zhang, Jian-Zhong

    2013-05-28

    To develop a real-time polymerase chain reaction (PCR) method to detect and quantify Campylobacter jejuni (C. jejuni) from stool specimens. Primers and a probe for real-time PCR were designed based on the specific DNA sequence of the hipO gene in C. jejuni. The specificity of the primers and probe were tested against a set of Campylobacter spp. and other enteric pathogens. The optimal PCR conditions were determined by testing a series of conditions with standard a C. jejuni template. The detection limits were obtained using purified DNA from bacterial culture and extracted DNA from the stool specimen. Two hundred and forty-two specimens were analyzed for the presence of C. jejuni by direct bacterial culture and real-time PCR. The optimal PCR system was determined using reference DNA templates, 1 × uracil-DNA glycosylase, 3.5 mmol/L MgCl2, 1.25 U platinum Taq polymerase, 0.4 mmol/L PCR nucleotide mix, 0.48 μmol/L of each primer, 0.2 μmol/L of probe and 2 μL of DNA template in a final volume of 25 μL. The PCR reaction was carried as follows: 95 °C for 4 min, followed by 45 cycles of 10 s at 95 °C and 30 s at 59 °C. The detection limit was 4.3 CFU/mL using purified DNA from bacterial culture and 10(3) CFU/g using DNA from stool specimens. Twenty (8.3%, 20/242) C. jejuni strains were isolated from bacterial culture, while 41 (16.9%, 41/242) samples were found to be positive by real-time PCR. DNA sequencing of the PCR product indicated the presence of C. jejuni in the specimen. One mixed infection of C. jejuni and Salmonella was detected in one specimen and the PCR test for this specimen was positive. The sensitivity of detection of C. jejuni from stool specimens was much higher using this PCR assay than using the direct culture method.

  10. Sleep restriction may lead to disruption in physiological attention and reaction time

    Directory of Open Access Journals (Sweden)

    Arbind Kumar Choudhary

    2016-07-01

    Full Text Available Sleepiness is the condition where for some reason fails to go into a sleep state and will have difficulty in remaining awake even while carrying out activities. Sleep restriction occurs when an individual fails to get enough sleep due to high work demands. The mechanism between sleep restriction and underlying brain physiology deficits is not well assumed. The objective of the present study was to investigate the mental attention (P300 and reaction time [visual (VRT and auditory (ART] among night watchmen, at subsequent; first (1st day, fourth (4th day and seventh (7th day of restricted sleep period. After exclusion and inclusion criteria, the study was performed among 50 watchmen (age=18–35 years (n=50 after providing written informed consent and divided into two group. Group I-(Normal sleep (n=28 working in day time and used to have normal sleep in night (≥8 h; Group II-(Restricted sleep (n=22 - working in night time and used to have less sleep in night (≤3 h. Statistical significance between the different groups was determined by the independent student ʻtʼ test and the significance level was fixed at p≤0.05. We observed that among all normal and restricted sleep watchmen there was not any significant variation in Karolinska Sleepiness Scale (KSS score, VRT and ART, along with latency and amplitude of P300 on 1st day of restricted sleep. However at subsequent on 4th day and 7th day of restricted sleep, there was significant increase in (KSSscore, and prolongation of VRT and ART as well as alteration in latency and amplitude of P300 wave in restricted sleep watchmen when compare to normal sleep watchmen. The present finding concludes that loss of sleep has major impact in dynamic change in mental attention and reaction time among watchmen employed in night shift. Professional regulations and work schedules should integrate sleep schedules before and during the work period as an essential dimension for their healthy life.

  11. Decay Time Measurement for Different Energy Depositions of Plastic Scintillator Fabricated by High Temperature Polymerization Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheol Ho; Son, Jaebum; Lee, Sangmin; Kim, Tae Hoon; Kim, Yong-Kyun [Hanyang University, Seoul (Korea, Republic of)

    2016-10-15

    Plastic scintillators are based on organic fluorite. They have many advantages such as fast rise and decay time, high optical transmission, ease of manufacturing, low cost, and large available size. For these reasons they are widely used for particle identification. Also, protection of people against a variety of threats (such as nuclear, radiological, and explosive) represents a true challenge along with the continuing development of science and technology. The plastic scintillator is widely used in various devise, which serves for nuclear, photonics, quantum, and high-energy physics. The plastic scintillator is probably the most widely used organic detector, and polystyrene is one of the most widely used materials in the making of the plastic scintillator detector. Thus, a styrene monomer as a solvent was used to fabricate the plastic scintillator by using high temperature polymerization reaction, and then the emission wavelength and the decay times for different energy depositions were measured by using the fabricated plastic scintillator. A plastic scintillator was fabricated to measure decay time for different energy depositions using the high temperature polymerization. Emission wavelength was measured of 426.05 nm to confirm a scintillator property using the spectrophotometer. Four gamma-ray sources (Cs-137, Co-60, Na-22, and Ba-133) were used to evaluate effect for decay time of different energy depositions. The average decay time of the fabricated plastic scintillator was measured to approximately 4.72 ns slightly higher more than commercial plastic scintillator. In future, light output and linearity will be measured to evaluate other property compared with the commercial scintillator.

  12. Reaction-time-resolved measurements of laser-induced fluorescence in a shock tube with a single laser pulse

    Science.gov (United States)

    Zabeti, S.; Fikri, M.; Schulz, C.

    2017-11-01

    Shock tubes allow for the study of ultra-fast gas-phase reactions on the microsecond time scale. Because the repetition rate of the experiments is low, it is crucial to gain as much information as possible from each individual measurement. While reaction-time-resolved species concentration and temperature measurements with fast absorption methods are established, conventional laser-induced fluorescence (LIF) measurements with pulsed lasers provide data only at a single reaction time. Therefore, fluorescence methods have rarely been used in shock-tube diagnostics. In this paper, a novel experimental concept is presented that allows reaction-time-resolved LIF measurements with one single laser pulse using a test section that is equipped with several optical ports. After the passage of the shock wave, the reactive mixture is excited along the center of the tube with a 266-nm laser beam directed through a window in the end wall of the shock tube. The emitted LIF signal is collected through elongated sidewall windows and focused onto the entrance slit of an imaging spectrometer coupled to an intensified CCD camera. The one-dimensional spatial resolution of the measurement translates into a reaction-time-resolved measurement while the species information can be gained from the spectral axis of the detected two-dimensional image. Anisole pyrolysis was selected as the benchmark reaction to demonstrate the new apparatus.

  13. Reaction-time-resolved measurements of laser-induced fluorescence in a shock tube with a single laser pulse.

    Science.gov (United States)

    Zabeti, S; Fikri, M; Schulz, C

    2017-11-01

    Shock tubes allow for the study of ultra-fast gas-phase reactions on the microsecond time scale. Because the repetition rate of the experiments is low, it is crucial to gain as much information as possible from each individual measurement. While reaction-time-resolved species concentration and temperature measurements with fast absorption methods are established, conventional laser-induced fluorescence (LIF) measurements with pulsed lasers provide data only at a single reaction time. Therefore, fluorescence methods have rarely been used in shock-tube diagnostics. In this paper, a novel experimental concept is presented that allows reaction-time-resolved LIF measurements with one single laser pulse using a test section that is equipped with several optical ports. After the passage of the shock wave, the reactive mixture is excited along the center of the tube with a 266-nm laser beam directed through a window in the end wall of the shock tube. The emitted LIF signal is collected through elongated sidewall windows and focused onto the entrance slit of an imaging spectrometer coupled to an intensified CCD camera. The one-dimensional spatial resolution of the measurement translates into a reaction-time-resolved measurement while the species information can be gained from the spectral axis of the detected two-dimensional image. Anisole pyrolysis was selected as the benchmark reaction to demonstrate the new apparatus.

  14. Short Time and Low Temperature Reaction between Metal Oxides through Microwave-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    S. M. V. Novais

    2016-01-01

    Full Text Available This work demonstrates the possibility of synthesis of cadmium tungstate at low temperatures using oxide precursors. Cadmium tungstate (CdWO4 scintillator was produced via microwave-assisted hydrothermal reaction using the precursors CdO and WO3. The methodology was based on microwave radiation for heating, which is remarkably faster than the solid-state route or conventional hydrothermal procedure. CdWO4 monoclinic (wolframite structure was successfully obtained at 120°C for synthesis times as short as 20 min. This route does not require the use of templates or surfactants and yields self-assembled nanorods with size of around 24 ± 9 nm width and 260 ± 47 nm length. The growth mechanism for the formation of CdWO4 involves microwave-induced dissociation of the reagents and solvation of Cd2+ and WO42- ions, which are free to move and start the nucleation process. The luminescence properties of the produced nanoparticles were investigated, presenting a broad emission band at around 500 nm, which is comparable to that observed for samples produced using other chemical routes. This result highlights the great potential of the proposed method as a low-cost and time saving process to fabricate luminescent oxide nanoparticles.

  15. A Strongly A-Stable Time Integration Method for Solving the Nonlinear Reaction-Diffusion Equation

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    Wenyuan Liao

    2015-01-01

    Full Text Available The semidiscrete ordinary differential equation (ODE system resulting from compact higher-order finite difference spatial discretization of a nonlinear parabolic partial differential equation, for instance, the reaction-diffusion equation, is highly stiff. Therefore numerical time integration methods with stiff stability such as implicit Runge-Kutta methods and implicit multistep methods are required to solve the large-scale stiff ODE system. However those methods are computationally expensive, especially for nonlinear cases. Rosenbrock method is efficient since it is iteration-free; however it suffers from order reduction when it is used for nonlinear parabolic partial differential equation. In this work we construct a new fourth-order Rosenbrock method to solve the nonlinear parabolic partial differential equation supplemented with Dirichlet or Neumann boundary condition. We successfully resolved the phenomena of order reduction, so the new method is fourth-order in time when it is used for nonlinear parabolic partial differential equations. Moreover, it has been shown that the Rosenbrock method is strongly A-stable hence suitable for the stiff ODE system obtained from compact finite difference discretization of the nonlinear parabolic partial differential equation. Several numerical experiments have been conducted to demonstrate the efficiency, stability, and accuracy of the new method.

  16. Trends and advances in food analysis by real-time polymerase chain reaction.

    Science.gov (United States)

    Salihah, Nur Thaqifah; Hossain, Mohammad Mosharraf; Lubis, Hamadah; Ahmed, Minhaz Uddin

    2016-05-01

    Analyses to ensure food safety and quality are more relevant now because of rapid changes in the quantity, diversity and mobility of food. Food-contamination must be determined to maintain health and up-hold laws, as well as for ethical and cultural concerns. Real-time polymerase chain reaction (RT-PCR), a rapid and inexpensive quantitative method to detect the presence of targeted DNA-segments in samples, helps in determining both accidental and intentional adulterations of foods by biological contaminants. This review presents recent developments in theory, techniques, and applications of RT-PCR in food analyses, RT-PCR addresses the limitations of traditional food analyses in terms of sensitivity, range of analytes, multiplexing ability, cost, time, and point-of-care applications. A range of targets, including species of plants or animals which are used as food ingredients, food-borne bacteria or viruses, genetically modified organisms, and allergens, even in highly processed foods can be identified by RT-PCR, even at very low concentrations. Microfluidic RT-PCR eliminates the separate sample-processing step to create opportunities for point-of-care analyses. We also cover the challenges related to using RT-PCR for food analyses, such as the need to further improve sample handling.

  17. Modeling Time-Dependent Behavior of Concrete Affected by Alkali Silica Reaction in Variable Environmental Conditions

    Science.gov (United States)

    Alnaggar, Mohammed; Di Luzio, Giovanni; Cusatis, Gianluca

    2017-01-01

    Alkali Silica Reaction (ASR) is known to be a serious problem for concrete worldwide, especially in high humidity and high temperature regions. ASR is a slow process that develops over years to decades and it is influenced by changes in environmental and loading conditions of the structure. The problem becomes even more complicated if one recognizes that other phenomena like creep and shrinkage are coupled with ASR. This results in synergistic mechanisms that can not be easily understood without a comprehensive computational model. In this paper, coupling between creep, shrinkage and ASR is modeled within the Lattice Discrete Particle Model (LDPM) framework. In order to achieve this, a multi-physics formulation is used to compute the evolution of temperature, humidity, cement hydration, and ASR in both space and time, which is then used within physics-based formulations of cracking, creep and shrinkage. The overall model is calibrated and validated on the basis of experimental data available in the literature. Results show that even during free expansions (zero macroscopic stress), a significant degree of coupling exists because ASR induced expansions are relaxed by meso-scale creep driven by self-equilibriated stresses at the meso-scale. This explains and highlights the importance of considering ASR and other time dependent aging and deterioration phenomena at an appropriate length scale in coupled modeling approaches. PMID:28772829

  18. Revealing the Radial Effect on Orientation Discrimination by Manual Reaction Time

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    Lixin Liang

    2017-11-01

    Full Text Available It has been shown that the sensitivity and accuracy of orientation perception in the periphery is significantly better when the orientations are radial with respect to the fixation point than when they are tangential. However, since perception and action may be dissociated, it is unclear whether the perceptual radial effect has a counterpart in reaction time (RT of motor responses. Furthermore, it is unknown whether or how stimulus-response-compatibility (SRC effect interacts with the radial effect to determine RT. To address these questions, we measured subjects' manual RT to grating stimuli that appeared across upper visual field (VF. We found that (1 RTs were significantly shorter when a grating was oriented closer to the radial direction than when it was oriented closer to the tangential direction even though the perceptual accuracies for the more radial and more tangential orientations were not significantly different under our experimental condition; (2 This RT version of the radial effect was larger in the left VF than in the right VF; (3 The radial effect and SRC effect interacted with each other to determine the overall RT. These results suggest that the RT radial effect reported here is not a passive reflection of the radial effect in perceptual accuracy, but instead, represents different processing time of radial and tangential orientations along the sensorimotor pathway.

  19. Moderate anxiety modifies the electromyographic activity of a forearm muscle during a time-reaction task in women.

    Science.gov (United States)

    Langlet, C; Hainaut, J P; Bolmont, B

    2017-03-16

    Arousal anxiety has a great impact on reaction time, physiological parameters and motor performance. Numerous studies have focused on the influence of anxiety on muscular activity during simple non ecologic task. We investigate the impact of a moderate state-anxiety (arousal stressor) on the specific component of a complex multi-joint ecologic movement during a reaction time task of auditory stimulus-response. Our objective is to know if central and peripheral voluntary motor processes were modulated in the same way by an arousal stressor. Eighteen women volunteers performed simple reaction time tasks of auditory stimulus-response. Video-recorded Stroop test with interferences was used to induced moderate state-anxiety. Electromyographic activity of the wrist extensor was recorded in order to analyse the two components of the reaction time: the premotor and motor time. In anxiogenic condition, an acceleration and an increase of muscular activity of the reaction time was obtained. This increase was due to a stronger muscle activity during the premotor time in the anxiogenic condition. Arousal anxiety has a different impact on central and peripheral voluntary motor processes. The modifications observed could be related to an increase in arousal related to a higher anxiety in order to prepare the body to act. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Solid-state reaction between p-benzoquinone and 4,4'-biphenol: a THz time-domain spectroscopic study

    Science.gov (United States)

    Liu, Guifeng; Zhao, Hongwei; Liu, Xiaohong; Wang, Wenfeng

    2011-07-01

    Terahertz time-domain spectroscopy (THz-TDS) was employed to record the progress of the reaction between p-benzoquinone (BQ) and 4,4'-biphenol (4BP) in the solid state. Through the THz-TDS, distinct absorption peaks of reactants and products were obtained. Sample preparations in the solid state, with and without grinding, influenced the conversion kinetics. Several kinetic equations or models were tried to fit the reaction data. A kinetic rate constant was obtained, with the reaction observed to be consistent with diffusion-controlled mechanisms. Differential scanning calorimetry and X-ray powder diffraction analyses were also used to characterize the solid-state reaction and products. The study shows that THz spectroscopy is a promising tool in evaluating the complex formation through solid-state reactions.

  1. Setting Reaction of Dental Resin-Modified Glass Ionomer Restoratives as a Function of Curing Depth and Postirradiation Time

    Directory of Open Access Journals (Sweden)

    Young Kyung Kim

    2015-01-01

    Full Text Available Specular reflectance Fourier transform infrared (SR-FTIR spectroscopy was used to study the setting reaction of dental resin-modified glass ionomer (RMGI restoratives as a function of curing depth and postirradiation time. Two light-cure and one tri-cure RMGI materials were selected and used according to the manufacturers’ instructions. Samples were prepared by filling the mixed materials into custom-made molds and then light-irradiating using a dental curing light. The degree of conversion and the extent of acid-base reaction of the materials at different depths (0, 1, 2, and 4 mm and postirradiation times (10 min, 1 day, and 7 days were determined using SR-FTIR spectroscopy in conjunction with the Kramers-Kronig (K-K transformation. The setting reaction was also investigated using microhardness measurements. The results showed that the depth of cure increased over time by the continuous acid-base reaction rather than photopolymerization or chemical polymerization. Microhardness tests seemed less suitable for studying the setting reaction as a function of postirradiation time, probably due to softening from the humidity. Analysis using specular reflectance in conjunction with the K-K algorithm was an easy and effective method for monitoring the setting reaction of dental RMGI materials.

  2. Evaluation of a simple test of reaction time for baseline concussion testing in a population of high school athletes.

    Science.gov (United States)

    MacDonald, James; Wilson, Julie; Young, Julie; Duerson, Drew; Swisher, Gail; Collins, Christy L; Meehan, William P

    2015-01-01

    A common sequela of concussions is impaired reaction time. Computerized neurocognitive tests commonly measure reaction time. A simple clinical test for reaction time has been studied previously in college athletes; whether this test is valid and reliable when assessing younger athletes remains unknown. Our study examines the reliability and validity of this test in a population of high school athletes. Cross-sectional study. Two American High Schools. High school athletes (N = 448) participating in American football or soccer during the academic years 2011 to 2012 and 2012 to 2013. All study participants completed a computerized baseline neurocognitive assessment that included a measure of reaction time (RT comp), in addition to a clinical measure of reaction time that assessed how far a standard measuring device would fall prior to the athlete catching it (RT clin). Validity was assessed by determining the correlation between RT clin and RT comp. Reliability was assessed by measuring the intraclass correlation coefficients (ICCs) between the repeated measures of RT clin and RT comp taken 1 year apart. In the first year of study, RT clin and RT comp were positively but weakly correlated (rs = 0.229, P Reaction time impairment commonly results from concussion and is among the most clinically important measures of the condition. The device evaluated in this study has previously been investigated as a reaction time measure in college athletes. This study investigates the clinical generalizability of the device in a younger population. A video abstract showing how the RT clin device is used in practice is available as Supplemental Digital Content 1, http://links.lww.com/JSM/A43.

  3. On the implications of a sex difference in the reaction times of sprinters at the Beijing Olympics.

    Directory of Open Access Journals (Sweden)

    David B Lipps

    Full Text Available Elite sprinters offer insights into the fastest whole body auditory reaction times. When, however, is a reaction so fast that it represents a false start? Currently, a false start is awarded if an athlete increases the force on their starting block above a given threshold before 100 ms has elapsed after the starting gun. To test the hypothesis that the fastest valid reaction times of sprinters really is 100 ms and that no sex difference exists in that time, we analyzed the fastest reaction times achieved by each of the 425 male and female sprinters who competed at the 2008 Beijing Olympics. After power transformation of the skewed data, a fixed effects ANOVA was used to analyze the effects of sex, race, round and lane position. The lower bounds of the 95, 99 and 99.9% confidence intervals were then calculated and back transformed. The mean fastest reaction time recorded by men was significantly faster than women (p<0.001. At the 99.9% confidence level, neither men nor women can react in 100 ms, but they can react in as little as 109 ms and 121 ms, respectively. However, that sex difference in reaction time is likely an artifact caused by using the same force threshold in women as men, and it permits a woman to false start by up to 21 ms without penalty. We estimate that female sprinters would have similar reaction times to male sprinters if the force threshold used at Beijing was lowered by 22% in order to account for their lesser muscle strength.

  4. On the Implications of a Sex Difference in the Reaction Times of Sprinters at the Beijing Olympics

    Science.gov (United States)

    Lipps, David B.; Galecki, Andrzej T.; Ashton-Miller, James A.

    2011-01-01

    Elite sprinters offer insights into the fastest whole body auditory reaction times. When, however, is a reaction so fast that it represents a false start? Currently, a false start is awarded if an athlete increases the force on their starting block above a given threshold before 100 ms has elapsed after the starting gun. To test the hypothesis that the fastest valid reaction times of sprinters really is 100 ms and that no sex difference exists in that time, we analyzed the fastest reaction times achieved by each of the 425 male and female sprinters who competed at the 2008 Beijing Olympics. After power transformation of the skewed data, a fixed effects ANOVA was used to analyze the effects of sex, race, round and lane position. The lower bounds of the 95, 99 and 99.9% confidence intervals were then calculated and back transformed. The mean fastest reaction time recorded by men was significantly faster than women (p<0.001). At the 99.9% confidence level, neither men nor women can react in 100 ms, but they can react in as little as 109 ms and 121 ms, respectively. However, that sex difference in reaction time is likely an artifact caused by using the same force threshold in women as men, and it permits a woman to false start by up to 21 ms without penalty. We estimate that female sprinters would have similar reaction times to male sprinters if the force threshold used at Beijing was lowered by 22% in order to account for their lesser muscle strength. PMID:22039438

  5. Reliability of the Dynavision™ D2 for Assessing Reaction Time Performance

    Directory of Open Access Journals (Sweden)

    Adam J. Wells

    2014-03-01

    Full Text Available Recently, the Dynavision™ D2 Visuomotor Training Device (D2 has emerged as a tool in the assessment of reaction time (RT; however, information regarding the reliability of the D2 have been limited, and to date, reliability data have been limited to non- generalizable samples. Therefore, the purpose of this study was to establish intraclass correlation coefficients (ICC2,1 for the D2 that are generalizable across a population of recreationally active young adults. Forty-two recreationally active men and women (age: 23.41 ± 4.84 years; height: 1.72 ± 0.11 m; mass: 76.62 ± 18.26 Kg completed 6 trials for three RT tasks of increasing complexity. Each trial was separated by at least 48-hours. A repeated measures ANOVA was used to detect differences in performance across the six trials. Intraclass correlation coefficients (ICC2,1 standard error of measurement (SEM, and minimal differences (MD were used to determine the reliability of the D2 from the two sessions with the least significant difference score. Moderate to strong reliability was demonstrated for visual RT (ICC2,1: 0.84, SEM: 0.033, and reactive ability in both Mode A and Mode B tasks (Mode A hits: ICC2,1: 0.75, SEM: 5.44; Mode B hits: ICC2,1: 0.73, SEM: 8.57. Motor RT (ICC2,1: 0.63, SEM: 0.035s showed fair reliability, while average RT per hit for Modes A and B showed moderate reliability (ICC2,1: 0.68, SEM: 0.43 s and ICC2,1: 0.72, SEM: 0.03 s respectively. It appears that one familiarization trial is necessary for the choice reaction time (CRT task while three familiarization trials are necessary for reactive RT tasks. In conclusion, results indicate that the Dynavision™ D2 is a reliable device to assess neuromuscular reactivity given that an adequate practice is provided. The data presented are generalizable to a population of recreationally active young adults.

  6. Synthesis of ferrofluids based on cobalt ferrite nanoparticles: Influence of reaction time on structural, morphological and magnetic properties

    Science.gov (United States)

    Amirabadizadeh, Ahmad; Salighe, Zohre; Sarhaddi, Reza; Lotfollahi, Zahra

    2017-07-01

    In this work, for first time the ferrofluids based on the cobalt ferrite (CoFe2O4) nanoparticles were prepared by the co-precipitation method at different reaction times (0.5-6.5 h). Crystal structure, morphology and magnetic properties of the cobalt ferrite nanoparticles and the ferrofluids based on the nanoparticles were studied by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM). The XRD patterns of CoFe2O4 nanoparticles synthesized at different reaction times indicated that all samples are single phase in accordance with inverse cubic spinel structure with space group Fd-3m, and no impurity phase was observed. By increasing the reaction time to 3.5 h, the lattice parameter and the average crystallites size increased and then afterwards decreased by increasing the reaction time. The microscopic studies indicated the formation of nanosized particles with nearly spherical in shape, whereas the average particle size for all samples is found to be less than 50 nm. The results of VSM also showed that the saturation magnetization and coercivity field of the cobalt ferrite nanoparticles and the ferrofluids were influenced by reaction time, whereas the ferrofluids have lower values of magnetic parameters than that of nanoparticles.

  7. Following a Chemical Reaction on the Millisecond Time Scale by Simultaneous X-ray and UV/Vis Spectroscopy.

    Science.gov (United States)

    Olivo, Giorgio; Barbieri, Alessia; Dantignana, Valeria; Sessa, Francesco; Migliorati, Valentina; Monte, Manuel; Pascarelli, Sakura; Narayanan, Theyencheri; Lanzalunga, Osvaldo; Di Stefano, Stefano; D'Angelo, Paola

    2017-07-06

    An innovative approach aimed at disclosing the mechanism of chemical reactions occurring in solution on the millisecond time scale is presented. Time-resolved energy dispersive X-ray absorption and UV/vis spectroscopies with millisecond resolution are used simultaneously to directly follow the evolution of both the oxidation state and the local structure of the metal center in an iron complex. Two redox reactions are studied, the former involving the transformation of FeII into two subsequent FeIII species and the latter involving the more complex FeII-FeIII-FeIV-FeIII sequence. The structural modifications occurring around the iron center are correlated to the reaction mechanisms. This combined approach has the potential to provide unique insights into reaction mechanisms in the liquid phase and represents a new powerful tool to characterize short-lived intermediates that are silent to common spectroscopic techniques.

  8. Improvement of attention span and reaction time with hyperbaric oxygen treatment in patients with toxic injury due to mold exposure.

    Science.gov (United States)

    Ezra, N; Dang, K; Heuser, G

    2011-01-01

    It is, by now, well established that mold toxins (mycotoxins) can cause significant adverse health effects. In this study, 15 subjects who developed an attention deficit disorder (ADD) and slowing of reaction time at the time of exposure to mold toxins were identified. Deficits in attention span and reaction time were documented not only by taking a careful history, but also by performing a Test of Variables of Attention (TOVA). The TOVA test provides an objective measure of these two variables. It was found that mold-exposed subjects show statistically significant decreases in attention span and significant increases in reaction time to stimuli compared to controls. After ten sessions of hyperbaric oxygen treatment (HBOT), a statistically significant improvement was seen in both measures. This preliminary study suggests promising outcomes in treating mold-exposed patients with hyperbaric oxygen.

  9. Relationships between Static and Dynamic Balance and Anticipation Time, Reaction Time in School Children at the Age of 10-12 Years

    Science.gov (United States)

    Bozkurt, Sinan; Erkut, Oya; Akkoç, Orkun

    2017-01-01

    The aim of this study is to investigate the relationship between anticipation time, reaction time and balance characteristics in school children at the age of 10-12 years. 11 males and 12 females, 23 students in total, studying at Istanbul Sancaktepe Ibn-i Sina Elementary School, whose average age was 11.06 years, average height was 142.78 cm and…

  10. Loudness perception in the domestic cat: reaction time estimates of equal loudness contours and recruitment effects.

    Science.gov (United States)

    May, Bradford J; Little, Nicole; Saylor, Stephanie

    2009-06-01

    The domestic cat is the primary physiological model of loudness coding and recruitment. At present, there are no published descriptions of loudness perception in this species. This study used a reaction time task to characterize loudness perception in six behaviorally trained cats. The psychophysical approach was based on the assumption that sounds of equal loudness elicit responses of equal latency. The resulting equal latency contours reproduced well-known features of human equal loudness contours. At the completion of normal baseline measures, the cats were exposed to intense sound to investigate the behavioral correlates of loudness recruitment, the abnormally rapid growth of loudness that is commonly associated with hearing loss. Observed recruitment effects were similar in magnitude to those that have been reported in hearing-impaired humans. Linear hearing aid amplification is known to improve speech intelligibility but also exacerbate recruitment in impaired listeners. The effects of speech spectra and amplification on recruitment were explored by measuring the growth of loudness for natural and amplified vowels before and after sound exposure. Vowels produced more recruitment than tones, and the effect was exacerbated by the selective amplification of formant structure. These findings support the adequacy of the domestic cat as a model system for future investigations of the auditory processes that underlie loudness perception, recruitment, and hearing aid design.

  11. Intraindividual variability in basic reaction time predicts middle-aged and older pilots' flight simulator performance.

    Science.gov (United States)

    Kennedy, Quinn; Taylor, Joy; Heraldez, Daniel; Noda, Art; Lazzeroni, Laura C; Yesavage, Jerome

    2013-07-01

    Intraindividual variability (IIV) is negatively associated with cognitive test performance and is positively associated with age and some neurological disorders. We aimed to extend these findings to a real-world task, flight simulator performance. We hypothesized that IIV predicts poorer initial flight performance and increased rate of decline in performance among middle-aged and older pilots. Two-hundred and thirty-six pilots (40-69 years) completed annual assessments comprising a cognitive battery and two 75-min simulated flights in a flight simulator. Basic and complex IIV composite variables were created from measures of basic reaction time and shifting and divided attention tasks. Flight simulator performance was characterized by an overall summary score and scores on communication, emergencies, approach, and traffic avoidance components. Although basic IIV did not predict rate of decline in flight performance, it had a negative association with initial performance for most flight measures. After taking into account processing speed, basic IIV explained an additional 8%-12% of the negative age effect on initial flight performance. IIV plays an important role in real-world tasks and is another aspect of cognition that underlies age-related differences in cognitive performance.

  12. Intraindividual Variability in Basic Reaction Time Predicts Middle-Aged and Older Pilots’ Flight Simulator Performance

    Science.gov (United States)

    2013-01-01

    Objectives. Intraindividual variability (IIV) is negatively associated with cognitive test performance and is positively associated with age and some neurological disorders. We aimed to extend these findings to a real-world task, flight simulator performance. We hypothesized that IIV predicts poorer initial flight performance and increased rate of decline in performance among middle-aged and older pilots. Method. Two-hundred and thirty-six pilots (40–69 years) completed annual assessments comprising a cognitive battery and two 75-min simulated flights in a flight simulator. Basic and complex IIV composite variables were created from measures of basic reaction time and shifting and divided attention tasks. Flight simulator performance was characterized by an overall summary score and scores on communication, emergencies, approach, and traffic avoidance components. Results. Although basic IIV did not predict rate of decline in flight performance, it had a negative association with initial performance for most flight measures. After taking into account processing speed, basic IIV explained an additional 8%–12% of the negative age effect on initial flight performance. Discussion. IIV plays an important role in real-world tasks and is another aspect of cognition that underlies age-related differences in cognitive performance. PMID:23052365

  13. Effect of vestibular stimulation on auditory and visual reaction time in relation to stress.

    Science.gov (United States)

    Rajagopalan, Archana; Kumar, Sai Sailesh; Mukkadan, Joseph Kurien

    2017-01-01

    The present study was undertaken to provide scientific evidence and for beneficial effects of vestibular stimulation for the management of stress-induced changes in auditory and visual reaction time (RT). A total of 240 healthy college students of the age group of 18-24 of either gender were a part of this research after obtaining written consent from them. RT for right and left response was measured for two auditory stimuli (low and high pitch) and visual stimuli (red and green) were recorded. A significant decrease in the visual RT for green light and red light was observed and stress-induced changes was effectively prevented followed by vestibular stimulation. Auditory RT for high pitch right and left response was significantly decreased and stress-induced changes was effectively prevented followed by vestibular stimulation. Vestibular stimulation is effective in boosting auditory and visual RT and preventing stress-induced changes in RT in males and females. We recommend incorporation of vestibular stimulation by swinging in our lifestyle for improving cognitive functions.

  14. Real-time studies of battery electrochemical reactions inside a transmission electron microscope.

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Kevin; Hudak, Nicholas S.; Liu, Yang; Liu, Xiaohua H.; Fan, Hongyou; Subramanian, Arunkumar; Shaw, Michael J.; Sullivan, John Patrick; Huang, Jian Yu

    2012-01-01

    We report the development of new experimental capabilities and ab initio modeling for real-time studies of Li-ion battery electrochemical reactions. We developed three capabilities for in-situ transmission electron microscopy (TEM) studies: a capability that uses a nanomanipulator inside the TEM to assemble electrochemical cells with ionic liquid or solid state electrolytes, a capability that uses on-chip assembly of battery components on to TEM-compatible multi-electrode arrays, and a capability that uses a TEM-compatible sealed electrochemical cell that we developed for performing in-situ TEM using volatile battery electrolytes. These capabilities were used to understand lithiation mechanisms in nanoscale battery materials, including SnO{sub 2}, Si, Ge, Al, ZnO, and MnO{sub 2}. The modeling approaches used ab initio molecular dynamics to understand early stages of ethylene carbonate reduction on lithiated-graphite and lithium surfaces and constrained density functional theory to understand ethylene carbonate reduction on passivated electrode surfaces.

  15. Choice reaction time to movement of eccentric visual targets during concurrent rotary acceleration

    Science.gov (United States)

    Hamerman, J. A.

    1979-01-01

    This study investigates the influence of concurrent rotary acceleration on choice reaction time (RT) to a small, accelerating visual cursor on a cathode-ray tube. Subjects sat in an enclosed rotating device at the center of rotation and observed a 3-mm dot accelerating at different rates across a cathode-ray tube. The dot was viewed at various eccentricities under conditions of visual stimulation alone and with concurrent rotary acceleration. Subjects responded to both vertical and horizontal dot movements. There was a significant inverse relationship between choice RT and level of dot acceleration (p less than .001), and a significant direct relationship between choice RT and eccentricity (p less than .001). There was no significant difference between choice RT to vertical or horizontal dot motion (p greater than .25), and choice RT was not significantly affected by concurrent rotary acceleration (p greater than .10). The results are discussed in terms of the effects of vestibular stimulation on choice RT to visual motion.

  16. Effect of noise stress on some cardiovascular parameters and audiovisual reaction time.

    Science.gov (United States)

    Saha, S; Gandhi, A; Das, S; Kaur, P; Singh, S H

    1996-01-01

    A study of the effect of noise stress on some of the physiological parameters was carried out on healthy male workers of thermal power station (exposed to sound level 90-113 dBA) and compared with age and sex matched healthy controls (exposed to sound level 48-66 dBA). The parameters recorded were heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), galvanic skin resistance (GSR), auditory and visual reaction time (ART and VRT) and audiogram. Significant impairment in audiogram at 3000 Hz and 4000 Hz, increase in HR, SBP, DBP and decrease in GSR, ART and VRT were recorded in workers who were exposed to noise stress. Also a higher prevalence of hypertension was observed in them and that they were at a higher risk of developing hypertension than the control group. It was also observed that these modifications are related to duration of exposure to noise stress. It is presumed that all the above extra auditory effects are due to activation of autonomic nervous system and hypothalamo-hypophyseal adrenal axis, and the resultant release of catecholamines from adrenal medulla due to noise stress.

  17. Chronic nicotine attenuates phencyclidine-induced impulsivity in a mouse serial reaction time task.

    Science.gov (United States)

    Scott, Daniel; Taylor, Jane R

    2014-02-01

    Schizophrenia is a disorder characterized by positive, negative, and cognitive symptoms. While positive symptoms can be effectively treated with typical antipsychotic medication, which generally affects the dopaminergic system, negative and cognitive symptoms, including attentional deficits and impulsive behavior, are less sensitive to standard treatments. It has further been well documented that schizophrenic patients use tobacco products at a rate much higher than the general population, and this persists despite treatment. It has been argued this behavior may be a form of self-medication, to alleviate some symptoms of schizophrenia. It has further been posited that prefrontal glutamatergic hypofunction may underlie some aspects of schizophrenia, and in accordance with this model, systemic phencyclidine has been used to model the disease. We employed a modified 5-choice serial reaction time test, a paradigm that is often used to investigate many of the treatment-resistant symptoms of schizophrenia including impulsivity, selective attention, and sustained attention/cognitive vigilance, to determine the medicinal effects of nicotine. We demonstrate that chronic oral, but not acute injections of nicotine can selectively attenuate phencyclidine-induced increases in impulsivity without affecting other measures of attention. This suggests that nicotine use by schizophrenics may provide some relief of distinct symptoms that involve impulsive behaviors. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Acute effects of exercise and active video games on adults' reaction time and perceived exertion.

    Science.gov (United States)

    Guzmán, José F; López-García, Jesús

    2016-11-01

    The purpose of the present study was to examine the acute effects of resting, aerobic exercise practised alone, and aerobic exercise with active video games (AVG), on complex reaction time (CRT) and the post-exercise acute rate of perceived exertion (RPE) in young healthy adults. The experimental group was composed of 92 healthy young adults, 78 males and 13 females (age M = 21.9 ± 2.7 years) who completed two sessions, A and B. In session A, participants rode 30 min on an ergometer, while in session B they exercised for 30 min on an ergometer while playing an AVG on a Wii. The control group was composed of 30 young adults, 26 males and 4 females (age M = 21.4 ± 2.9 years) who rested for 30 min. In each session, a CRT task was performed before and after exercising or resting, and post-exercise global RPE was noted. Repeated measures general linear model (GLM) and Wilcoxon tests were performed. (1) Both aerobic exercise alone and aerobic exercise combined with AVG improved CRT, while resting did not; (2) aerobic exercise combined with AVG did not improve CRT more than aerobic exercise only; and (3) RPE was lower after aerobic exercise combined with AVG compared with aerobic exercise only. In young adults, exercise produces acute benefits on CRT, and practising exercise with AVG helps to decrease RPE.

  19. Inhibition of Return in Fear of Spiders: Discrepant Eye Movement and Reaction Time Data

    Directory of Open Access Journals (Sweden)

    Elisa Berdica

    2014-01-01

    Full Text Available Inhibition of return (IOR refers to a bias against returning the attention to a previously attended location. As a foraging facilitator it is thought to facilitate systematic visual search. With respect to neutral stimuli, this is generally thought to be adaptive, but when threatening stimuli appear in our environment, such a bias may be maladaptive. This experiment investigated the influence of phobia-related stimuli on the IOR effect using a discrimination task. A sample of 50 students (25 high, 25 low in spider fear completed an IOR task including schematic representations of spiders or butterflies as targets. Eye movements were recorded and to assess discrimination among targets, participants indicated with button presses if targets were spiders or butterflies. Reaction time data did not reveal a significant IOR effect but a significant interaction of group and target; spider fearful participants were faster to respond to spider targets than to butterflies. Furthermore, eye-tracking data showed a robust IOR effect independent of stimulus category. These results offer a more comprehensive assessment of the motor and oculomotor factors involved in the IOR effect.

  20. Release the BEESTS: Bayesian Estimation of Ex-Gaussian STop-Signal Reaction Time Distributions

    Directory of Open Access Journals (Sweden)

    Dora eMatzke

    2013-12-01

    Full Text Available The stop-signal paradigm is frequently used to study response inhibition. Inthis paradigm, participants perform a two-choice response time task wherethe primary task is occasionally interrupted by a stop-signal that promptsparticipants to withhold their response. The primary goal is to estimatethe latency of the unobservable stop response (stop signal reaction timeor SSRT. Recently, Matzke, Dolan, Logan, Brown, and Wagenmakers (inpress have developed a Bayesian parametric approach that allows for theestimation of the entire distribution of SSRTs. The Bayesian parametricapproach assumes that SSRTs are ex-Gaussian distributed and uses Markovchain Monte Carlo sampling to estimate the parameters of the SSRT distri-bution. Here we present an efficient and user-friendly software implementa-tion of the Bayesian parametric approach —BEESTS— that can be appliedto individual as well as hierarchical stop-signal data. BEESTS comes withan easy-to-use graphical user interface and provides users with summarystatistics of the posterior distribution of the parameters as well various diag-nostic tools to assess the quality of the parameter estimates. The softwareis open source and runs on Windows and OS X operating systems. In sum,BEESTS allows experimental and clinical psychologists to estimate entiredistributions of SSRTs and hence facilitates the more rigorous analysis ofstop-signal data.

  1. Effect of vestibular stimulation on auditory and visual reaction time in relation to stress

    Directory of Open Access Journals (Sweden)

    Archana Rajagopalan

    2017-01-01

    Full Text Available The present study was undertaken to provide scientific evidence and for beneficial effects of vestibular stimulation for the management of stress-induced changes in auditory and visual reaction time (RT. A total of 240 healthy college students of the age group of 18-24 of either gender were a part of this research after obtaining written consent from them. RT for right and left response was measured for two auditory stimuli (low and high pitch and visual stimuli (red and green were recorded. A significant decrease in the visual RT for green light and red light was observed and stress-induced changes was effectively prevented followed by vestibular stimulation. Auditory RT for high pitch right and left response was significantly decreased and stress-induced changes was effectively prevented followed by vestibular stimulation. Vestibular stimulation is effective in boosting auditory and visual RT and preventing stress-induced changes in RT in males and females. We recommend incorporation of vestibular stimulation by swinging in our lifestyle for improving cognitive functions.

  2. Relationship of Reaction Time to Perception of a Stimulus and Volitionally Delayed Response.

    Science.gov (United States)

    Meador, Kimford J; Boyd, Alan; Loring, David W

    2017-06-01

    Initiation of response in a simple reaction time (RT) task may precede conscious perception of the stimulus. Since volitionally delayed responses may require conscious perception of the stimulus before response initiation, it has been hypothesized that volitionally delayed responses will markedly delay RT. We conducted two experiments with separate groups of healthy volunteers (n=16; n=13) who performed computerized simple and choice RT tasks. In the standard condition, we instructed the participants to respond to a visual stimulus by pushing a button as quickly as possible. In the second condition, we instructed the participants to respond after a slight volitional delay. The second experiment had an additional volitional delay condition in which we asked participants to delay their responses by an estimated 50% above their usual standard response. We found marked delays and increased variability when participants volitionally delayed their responses, averaging 322 ms for standard and 861 ms for delayed simple RTs (267% increase), and 650 ms for standard and 1018 ms for delayed choice RTs (157% increase). Effects did not differ across age, sex, or handedness. However, a minority of participants did not meaningfully delay their RT during the volitional delay conditions. On average, participants had marked delays when they tried to delay their responses slightly, but a subset of participants exhibited essentially no delay despite trying to delay. We suggest some potential mechanisms that future investigations might delineate.

  3. Influence of the Total Gas Flow at Different Reaction Times for CVD-Graphene Synthesis on Polycrystalline Nickel

    Directory of Open Access Journals (Sweden)

    M. P. Lavin-Lopez

    2016-01-01

    Full Text Available Optimization of the total gas flow (CH4+H2 during the reaction step for different reaction times for CVD-graphene synthesis on polycrystalline nickel foil using an atmospheric pressure set-up is reported. A thickness value related to number of graphene layers in each of the synthesized samples was determined using an Excel-VBA application. This method assigned a thickness value between 1 and 1000 and provided information on the percentage of each type of graphene (monolayer, bilayer, and multilayer deposited onto the polycrystalline nickel sheet. The influence of the total gas flow during the reaction step and the reaction time was studied in detail. Optical microscopy showed that samples were covered with different types of graphene, such as multilayer, few-layer, bilayer, and monolayer graphene. The synthesis variables were optimized according to the thickness value and the results were verified by Raman spectroscopy. The best conditions were obtained with a reaction temperature of 980°C, a CH4/H2 flow rate ratio of 0.07 v/v, a reaction time of 1 minute, and a total gas flow of 80 NmL/min. In the sample obtained under the optimized conditions, 80% of the area was covered with monolayer graphene and less than 1% with multilayer graphene.

  4. Kinetic Analysis of Parallel-Consecutive First-Order Reactions with a Reversible Step: Concentration-Time Integrals Method

    Science.gov (United States)

    Mucientes, A. E.; de la Pena, M. A.

    2009-01-01

    The concentration-time integrals method has been used to solve kinetic equations of parallel-consecutive first-order reactions with a reversible step. This method involves the determination of the area under the curve for the concentration of a given species against time. Computer techniques are used to integrate experimental curves and the method…

  5. AN INVESTIGATION OF LEG AND TRUNK STRENGTH AND REACTION TIMES OF HARD-STYLE MARTIAL ARTS PRACTITIONERS

    Directory of Open Access Journals (Sweden)

    Oliver O'Donovan

    2006-07-01

    Full Text Available The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT, choice reaction times (CRT and movement times (MT. Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05. During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT] but were significantly faster in moving to press another button [movement time (MT]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts

  6. Green's-function reaction dynamics: A particle-based approach for simulating biochemical networks in time and space

    NARCIS (Netherlands)

    van Zon, J.S.; ten Wolde, P.R.

    2005-01-01

    We have developed a new numerical technique, called Green's-function reaction dynamics (GFRD), that makes it possible to simulate biochemical networks at the particle level and in both time and space. In this scheme, a maximum time step is chosen such that only single particles or pairs of particles

  7. Impaired motor inhibition in adults who stutter - evidence from speech-free stop-signal reaction time tasks.

    Science.gov (United States)

    Markett, Sebastian; Bleek, Benjamin; Reuter, Martin; Prüss, Holger; Richardt, Kirsten; Müller, Thilo; Yaruss, J Scott; Montag, Christian

    2016-10-01

    Idiopathic stuttering is a fluency disorder characterized by impairments during speech production. Deficits in the motor control circuits of the basal ganglia have been implicated in idiopathic stuttering but it is unclear how these impairments relate to the disorder. Previous work has indicated a possible deficiency in motor inhibition in children who stutter. To extend these findings to adults, we designed two experiments to probe executive motor control in people who stutter using manual reaction time tasks that do not rely on speech production. We used two versions of the stop-signal reaction time task, a measure for inhibitory motor control that has been shown to rely on the basal ganglia circuits. We show increased stop-signal reaction times in two independent samples of adults who stutter compared to age- and sex-matched control groups. Additional measures involved simple reaction time measurements and a task-switching task where no group difference was detected. Results indicate a deficiency in inhibitory motor control in people who stutter in a task that does not rely on overt speech production and cannot be explained by general deficits in executive control or speeded motor execution. This finding establishes the stop-signal reaction time as a possible target for future experimental and neuroimaging studies on fluency disorders and is a further step towards unraveling the contribution of motor control deficits to idiopathic stuttering. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Saccadic reaction times to audiovisual stimuli show effects of oscillatory phase reset.

    Directory of Open Access Journals (Sweden)

    Adele Diederich

    Full Text Available Initiating an eye movement towards a suddenly appearing visual target is faster when an accessory auditory stimulus occurs in close spatiotemporal vicinity. Such facilitation of saccadic reaction time (SRT is well-documented, but the exact neural mechanisms underlying the crossmodal effect remain to be elucidated. From EEG/MEG studies it has been hypothesized that coupled oscillatory activity in primary sensory cortices regulates multisensory processing. Specifically, it is assumed that the phase of an ongoing neural oscillation is shifted due to the occurrence of a sensory stimulus so that, across trials, phase values become highly consistent (phase reset. If one can identify the phase an oscillation is reset to, it is possible to predict when temporal windows of high and low excitability will occur. However, in behavioral experiments the pre-stimulus phase will be different on successive repetitions of the experimental trial, and average performance over many trials will show no signs of the modulation. Here we circumvent this problem by repeatedly presenting an auditory accessory stimulus followed by a visual target stimulus with a temporal delay varied in steps of 2 ms. Performing a discrete time series analysis on SRT as a function of the delay, we provide statistical evidence for the existence of distinct peak spectral components in the power spectrum. These frequencies, although varying across participants, fall within the beta and gamma range (20 to 40 Hz of neural oscillatory activity observed in neurophysiological studies of multisensory integration. Some evidence for high-theta/alpha activity was found as well. Our results are consistent with the phase reset hypothesis and demonstrate that it is amenable to testing by purely psychophysical methods. Thus, any theory of multisensory processes that connects specific brain states with patterns of saccadic responses should be able to account for traces of oscillatory activity in observable

  9. Widely applicable MATLAB routines for automated analysis of saccadic reaction times.

    Science.gov (United States)

    Leppänen, Jukka M; Forssman, Linda; Kaatiala, Jussi; Yrttiaho, Santeri; Wass, Sam

    2015-06-01

    Saccadic reaction time (SRT) is a widely used dependent variable in eye-tracking studies of human cognition and its disorders. SRTs are also frequently measured in studies with special populations, such as infants and young children, who are limited in their ability to follow verbal instructions and remain in a stable position over time. In this article, we describe a library of MATLAB routines (Mathworks, Natick, MA) that are designed to (1) enable completely automated implementation of SRT analysis for multiple data sets and (2) cope with the unique challenges of analyzing SRTs from eye-tracking data collected from poorly cooperating participants. The library includes preprocessing and SRT analysis routines. The preprocessing routines (i.e., moving median filter and interpolation) are designed to remove technical artifacts and missing samples from raw eye-tracking data. The SRTs are detected by a simple algorithm that identifies the last point of gaze in the area of interest, but, critically, the extracted SRTs are further subjected to a number of postanalysis verification checks to exclude values contaminated by artifacts. Example analyses of data from 5- to 11-month-old infants demonstrated that SRTs extracted with the proposed routines were in high agreement with SRTs obtained manually from video records, robust against potential sources of artifact, and exhibited moderate to high test-retest stability. We propose that the present library has wide utility in standardizing and automating SRT-based cognitive testing in various populations. The MATLAB routines are open source and can be downloaded from http://www.uta.fi/med/icl/methods.html .

  10. Using Reaction Times and Binary Responses to Estimate Psychophysical Performance: An Information Theoretic Analysis

    Directory of Open Access Journals (Sweden)

    James V Stone

    2014-03-01

    Full Text Available As the strength of a stimulus increases, the proportions of correct binary responses increases, which define the psychometric function. Simultaneously, mean reaction times (RT decrease, which collectively define the chronometric function. However, RTs are traditionally ignored when estimating psychophysical parameters, even though they may provide additional Shannon information. Here, we extend Palmer et al's (2005 proportional-rate diffusion model (PRD by: (a fitting individual RTs to an inverse Gaussian distribution, (b including lapse rate, (c point-of-subjective-equality (PSE parameters, and, (d using a two-alternative forced choice (2AFC design based on the proportion of times a variable comparison stimulus is chosen. Maximum likelihood estimates of mean RT values (from fitted inverse Gaussians and binary responses were fitted both separately and in combination to this extended PRD (EPRD model, to obtain psychophysical parameter values. Values estimated from binary responses alone (ie the psychometric function were found to be similar to those estimated from RTs alone (ie the chronometric function, which provides support for the underlying diffusion model. The EPRD model was then used to estimate the mutual information between binary responses and stimulus strength, and between RTs and stimulus strength. These provide conservative bounds for the average amount of Shannon information the observer gains about stimulus strength on each trial. For the human experiment reported here, the observer gains between 2.68 and 3.55 bits/trial. These bounds are monotonically related to a new measure, the {em Shannon increment}, which is the expected value of the smallest change in stimulus strength detectable by an observer.

  11. Using reaction times and binary responses to estimate psychophysical performance: an information theoretic analysis.

    Science.gov (United States)

    Stone, James V

    2014-01-01

    As the strength of a stimulus increases, the proportions of correct binary responses increases, which define the psychometric function. Simultaneously, mean reaction times (RT) decrease, which collectively define the chronometric function. However, RTs are traditionally ignored when estimating psychophysical parameters, even though they may provide additional Shannon information. Here, we extend Palmer et al's (2005) proportional-rate diffusion model (PRD) by: (a) fitting individual RTs to an inverse Gaussian distribution, (b) including lapse rate, (c) point-of-subjective-equality (PSE) parameters, and, (d) using a two-alternative forced choice (2AFC) design based on the proportion of times a variable comparison stimulus is chosen. Maximum likelihood estimates of mean RT values (from fitted inverse Gaussians) and binary responses were fitted both separately and in combination to this extended PRD (EPRD) model, to obtain psychophysical parameter values. Values estimated from binary responses alone (i.e., the psychometric function) were found to be similar to those estimated from RTs alone (i.e., the chronometric function), which provides support for the underlying diffusion model. The EPRD model was then used to estimate the mutual information between binary responses and stimulus strength, and between RTs and stimulus strength. These provide conservative bounds for the average amount of Shannon information the observer gains about stimulus strength on each trial. For the human experiment reported here, the observer gains between 2.68 and 3.55 bits/trial. These bounds are monotonically related to a new measure, the Shannon increment, which is the expected value of the smallest change in stimulus strength detectable by an observer.

  12. Comparison of Motor Inhibition in Variants of the Instructed-Delay Choice Reaction Time Task.

    Science.gov (United States)

    Quoilin, Caroline; Lambert, Julien; Jacob, Benvenuto; Klein, Pierre-Alexandre; Duque, Julie

    2016-01-01

    Using instructed-delay choice reaction time (RT) paradigms, many previous studies have shown that the motor system is transiently inhibited during response preparation: motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex are typically suppressed during the delay period. This effect has been observed in both selected and non-selected effectors, although MEP changes in selected effectors have been more inconsistent across task versions. Here, we compared changes in MEP amplitudes in three different variants of an instructed-delay choice RT task. All variants required participants to choose between left and right index finger movements but the responses were either provided "in the air" (Variant 1), on a regular keyboard (Variant 2), or on a response device designed to control from premature responses (Variant 3). The task variants also differed according to the visual layout (more concrete in Variant 3) and depending on whether participants received a feedback of their performance (absent in Variant 1). Behavior was globally comparable between the three variants of the task although the propensity to respond prematurely was highest in Variant 2 and lowest in Variant 3. MEPs elicited in a non-selected hand were similarly suppressed in the three variants of the task. However, significant differences emerged when considering MEPs elicited in the selected hand: these MEPs were suppressed in Variants 1 and 3 whereas they were often facilitated in Variant 2, especially in the right dominant hand. In conclusion, MEPs elicited in selected muscles seem to be more sensitive to small variations to the task design than those recorded in non-selected effectors, probably because they reflect a complex combination of inhibitory and facilitatory influences on the motor output system. Finally, the use of a standard keyboard seems to be particularly inappropriate because it encourages participants to respond promptly with no

  13. Theory of Visual Attention (TVA) applied to mice in the 5-choice serial reaction time task.

    Science.gov (United States)

    Fitzpatrick, C M; Caballero-Puntiverio, M; Gether, U; Habekost, T; Bundesen, C; Vangkilde, S; Woldbye, D P D; Andreasen, J T; Petersen, A

    2017-03-01

    The 5-choice serial reaction time task (5-CSRTT) is widely used to measure rodent attentional functions. In humans, many attention studies in healthy and clinical populations have used testing based on Bundesen's Theory of Visual Attention (TVA) to estimate visual processing speeds and other parameters of attentional capacity. We aimed to bridge these research fields by modifying the 5-CSRTT's design and by mathematically modelling data to derive attentional parameters analogous to human TVA-based measures. C57BL/6 mice were tested in two 1-h sessions on consecutive days with a version of the 5-CSRTT where stimulus duration (SD) probe length was varied based on information from previous TVA studies. Thereafter, a scopolamine hydrobromide (HBr; 0.125 or 0.25 mg/kg) pharmacological challenge was undertaken, using a Latin square design. Mean score values were modelled using a new three-parameter version of TVA to obtain estimates of visual processing speeds, visual thresholds and motor response baselines in each mouse. The parameter estimates for each animal were reliable across sessions, showing that the data were stable enough to support analysis on an individual level. Scopolamine HBr dose-dependently reduced 5-CSRTT attentional performance while also increasing reward collection latency at the highest dose. Upon TVA modelling, scopolamine HBr significantly reduced visual processing speed at both doses, while having less pronounced effects on visual thresholds and motor response baselines. This study shows for the first time how 5-CSRTT performance in mice can be mathematically modelled to yield estimates of attentional capacity that are directly comparable to estimates from human studies.

  14. Structural integrity of callosal midbody influences intermanual transfer in a motor reaction-time task.

    Science.gov (United States)

    Bonzano, Laura; Tacchino, Andrea; Roccatagliata, Luca; Mancardi, Giovanni Luigi; Abbruzzese, Giovanni; Bove, Marco

    2011-02-01

    Training one hand on a motor task results in performance improvements in the other hand, also when stimuli are randomly presented (nonspecific transfer). Corpus callosum (CC) is the main structure involved in interhemispheric information transfer; CC pathology occurs in patients with multiple sclerosis (PwMS) and is related to altered performance of tasks requiring interhemispheric transfer of sensorimotor information. To investigate the role of CC in nonspecific transfer during a pure motor reaction-time task, we combined motor behavior with diffusion tensor imaging analysis in PwMS. Twenty-two PwMS and 10 controls, all right-handed, were asked to respond to random stimuli with appropriate finger opposition movements with the right (learning) and then the left (transfer) hand. PwMS were able to improve motor performance reducing response times with practice with a trend similar to controls and preserved the ability to transfer the acquired motor information from the learning to the transfer hand. A higher variability in the transfer process, indicated by a significantly larger standard deviation of mean nonspecific transfer, was found in the PwMS group with respect to the control group, suggesting the presence of subtle impairments in interhemispheric communication in some patients. Then, we correlated the amount of nonspecific transfer with mean fractional anisotropy (FA) values, indicative of microstructural damage, obtained in five CC subregions identified on PwMS's FA maps. A significant correlation was found only in the subregion including posterior midbody (Pearson's r = 0.74, P = 0.003), which thus seems to be essential for the interhemispheric transfer of information related to pure sensorimotor tasks. Copyright © 2010 Wiley-Liss, Inc.

  15. Real-time polymerase chain reaction correlates well with clinical diagnosis of Clostridium difficile infection.

    Science.gov (United States)

    Berry, N; Sewell, B; Jafri, S; Puli, C; Vagia, S; Lewis, A M; Davies, D; Rees, E; Ch'ng, C L

    2014-06-01

    To determine the clinical utility of a rapid molecular assay for Clostridium difficile infection (CDI) in an acute hospital setting. From March to September 2011, stool specimens from inpatients in two acute hospitals with suspected CDI were tested prospectively by routine cell culture cytotoxin neutralization assay (CCNA), real-time polymerase chain reaction (PCR) using the GeneXpert (Cepheid Inc., Sunnyvale, CA, USA), and a dual testing algorithm [glutamate dehydrogenase (GDH)/toxin enzyme immuno-assay, Premier, Launch Diagnostics, Longfield, UK]. All patients with positive PCR, CCNA or discrepant results were reviewed by a multi-disciplinary team (treating clinician, gastroenterologist, microbiologist and infection control nurse). C. difficile detection rates were 11.7% (PCR), 6% (CCNA) and 13.8% (GDH). Out of 1034 stool specimens included in the study, 974 (94.1%) had concordant CCNA and PCR results. Eighty-nine percent (886/985) had concordant CCNA, PCR and GDH results, and 94.4% (930/985) had concordant GDH and PCR results. Using clinical diagnosis as the reference, PCR had sensitivity of 99.1%, specificity of 98.9%, positive predictive value (PPV) of 91.9% and negative predictive value (NPV) of 99.9%. CCNA on a single sample had sensitivity of 51%, specificity of 99.4%, PPV of 91.9% and NPV of 94.3%. GDH had sensitivity of 83.8%, specificity of 94.5%, PPV of 64.7% and NPV of 97.9%. Almost twice as many patients were positive by PCR compared with CCNA (121 vs 62); 54/59 of those with discrepant results were clinically confirmed as CDI. Rapid diagnosis of CDI using PCR was timely, accurate and correlated well with clinical diagnosis. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  16. An investigation of leg and trunk strength and reaction times of hard-style martial arts practitioners.

    Science.gov (United States)

    Donovan, Oliver O; Cheung, Jeanette; Catley, Maria; McGregor, Alison H; Strutton, Paul H

    2006-01-01

    The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05). During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT)] but were significantly faster in moving to press another button [movement time (MT)]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts. Key PointsMartial artists undertaking hard-style martial arts have greater strength in their knee flexor and extensor muscles as tested under isokinetic testing. Under isometric testing conditions they have stronger knee extensors only.The trunk musculature is generally higher under both conditions of testing in the martial artists, although not significantly.The total reaction times of the martial artists to an auditory stimulus were significantly faster than the control participants. When analysed further it was revealed that the decrease in reaction time

  17. Real Time Polymerase Chain Reaction (rt-PCR): A New Patent to Diagnostic Purposes for Paracoccidioidomycosis.

    Science.gov (United States)

    Rocha-Silva, Fabiana; Gomes, Luciana I; Gracielle-Melo, Cidiane; Goes, Alfredo M; Caligiorne, Rachel B

    2017-01-01

    Paracoccidioidomycosis (PCM) is a systemic mycosis caused by dimorphic fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii. It is prevalent in Latin American, mainly in Brazil. Therefore, PCM has fundamental impact on the Brazilian global economy, especially in public health system, since it is affecting economical active population in different country regions. The present study aimed to standardize the Real Time-Polymerase Chain Reaction (rt-PCR) for an efficient and safe PCM diagnosis amplifying the recombinant protein PB27 gene, only expressed by specimens of Paracoccidioides genus. To standardize a methodology of rt-PCR using species-specific primers and probe designed for annealing in this specific region of the fungi´s genome, amplifying the recombinant protein PB27 gene, only expressed by specimens of Paracoccidioides genus. Followed by design in silico, experiments were performed in vitro to determine rt-PCR specificity, efficiency and genome detection limit. The primers and probe sequences were deposited in Brazilian Coordination of Technological Innovation and Transfer (CTIT), under patent reference number BR1020160078830. The present study demonstrated the rt-PCR applicability for support on diagnosis of paracoccidioidomycosis, presenting low cost, which makes it affordable for public health services in developing countries as Brazil. It is noteworthy that it is necessary to validate this methodology using clinical samples before to use as a safe method of diagnosis. A review of all patents related to this topic was performed and it was shown that, to date, there are no records of patent on kits for paracoccidioidomycosis´s diagnostic. Indeed, there is still a lot to go to reach this goal. The reaction developed was standardized and patented, opening perspectives to molecular diagnosis development for paracoccidioidomycosis, since rt-PCR can be applied to a broad spectrum of infectious diseases. It would need to be tested in biological

  18. Type I photosensitized reactions of oxopurines. Kinetics and thermodynamics of the reaction with triplet benzophenone by time-resolved photoacoustic spectroscopy

    Science.gov (United States)

    Murgida, Daniel H.; Erra Balsells, Rosa; Crippa, Pier Raimondo; Viappiani, Cristiano

    1998-09-01

    Benzophenone photosensitized reactions of caffeine, theophylline and theobromine were investigated in acetonitrile by time-resolved laser-induced photoacoustics. In the three cases global quenching rate constants of triplet benzophenone were measured as a function of temperature and it was observed that this is a non-activated process. Besides, for theobromine and theophylline heats for NH hydrogen abstraction reactions were determined. In agreement with semiempirical calculation predictions, hydrogen abstraction is thermodynamically more favorable and faster for theophylline (Δ H=-265 kJ mol -1, kr=9.6×10 8 M -1 s -1) than for theobromine (Δ H=-168 kJ mol -1, kr=3.7×10 8 M -1 s -1).

  19. Synthesis of ferrofluids based on cobalt ferrite nanoparticles: Influence of reaction time on structural, morphological and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Amirabadizadeh, Ahmad; Salighe, Zohre; Sarhaddi, Reza, E-mail: reza.sarhaddi@birjand.ac.ir; Lotfollahi, Zahra

    2017-07-15

    Highlights: • Ferrofluids based on cobalt ferrite nanoparticles were synthesized by co-precipitation method. • The crystallite and particle size of cobalt ferrite can be controlled effectively by reaction time. • The ferrofluids have lower values of saturation magnetization and coercivity as compared to nanoparticles. • By increasing the size of nanoparticles, the narrower and sharper spikes of ferrofluids are formed. - Abstract: In this work, for first time the ferrofluids based on the cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles were prepared by the co-precipitation method at different reaction times (0.5–6.5 h). Crystal structure, morphology and magnetic properties of the cobalt ferrite nanoparticles and the ferrofluids based on the nanoparticles were studied by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM). The XRD patterns of CoFe{sub 2}O{sub 4} nanoparticles synthesized at different reaction times indicated that all samples are single phase in accordance with inverse cubic spinel structure with space group Fd-3m, and no impurity phase was observed. By increasing the reaction time to 3.5 h, the lattice parameter and the average crystallites size increased and then afterwards decreased by increasing the reaction time. The microscopic studies indicated the formation of nanosized particles with nearly spherical in shape, whereas the average particle size for all samples is found to be less than 50 nm. The results of VSM also showed that the saturation magnetization and coercivity field of the cobalt ferrite nanoparticles and the ferrofluids were influenced by reaction time, whereas the ferrofluids have lower values of magnetic parameters than that of nanoparticles.

  20. The effects of arm movement on reaction time in patients with latent and active upper trapezius myofascial trigger point.

    Science.gov (United States)

    Yassin, Marzieh; Talebian, Saeed; Ebrahimi Takamjani, Ismail; Maroufi, Nader; Ahmadi, Amir; Sarrafzadeh, Javad; Emrani, Anita

    2015-01-01

    Myofascial pain syndrome is a significant source of mechanical pain. The aim of this study was to investigate the effects of arm movement on reaction time in females with latent and active upper trapezius myofascial trigger point. In this interventional study, a convenience sample of fifteen women with one active MTP, fifteen women with one latent MTP in the upper trapezius, and fifteen normal healthy women were participated. Participants were asked to stand for 10 seconds in an erect standing position. Muscle reaction times were recorded including anterior deltoid (AD), cervical paraspinal (CP) lumbar paraspinal (LP), both of upper trapezius (UT), sternocleidomastoid (SCM) and medial head of gastrocnemius (GcM). Participants were asked to flex their arms in response to a sound stimulus preceded by a warning sound stimulus. Data were analyzed using one-way ANOVA Test. There was significant differences in motor time and reaction time between active and control groups (ptime between active and passive groups except for UT without MTP and SCM (ptimes between latent MTP and control groups. Furthermore, there was no significant difference in premotor times between the three groups. The present study shows that patients with active MTP need more time to react to stimulus, but patients with latent MTP are similar to healthy subjects in the reaction time. Patients with active MTP had less compatibility with environmental stimulations, and they responded to a specific stimulation with variability in Surface Electromyography (SEMG).

  1. The effects of arm movement on reaction time in patients with latent and active upper trapezius myofascial trigger point

    Science.gov (United States)

    Yassin, Marzieh; Talebian, Saeed; Ebrahimi Takamjani, Ismail; Maroufi, Nader; Ahmadi, Amir; Sarrafzadeh, Javad; Emrani, Anita

    2015-01-01

    Background: Myofascial pain syndrome is a significant source of mechanical pain. The aim of this study was to investigate the effects of arm movement on reaction time in females with latent and active upper trapezius myofascial trigger point. Methods: In this interventional study, a convenience sample of fifteen women with one active MTP, fifteen women with one latent MTP in the upper trapezius, and fifteen normal healthy women were participated. Participants were asked to stand for 10 seconds in an erect standing position. Muscle reaction times were recorded including anterior deltoid (AD), cervical paraspinal (CP) lumbar paraspinal (LP), both of upper trapezius (UT), sternocleidomastoid (SCM) and medial head of gastrocnemius (GcM). Participants were asked to flex their arms in response to a sound stimulus preceded by a warning sound stimulus. Data were analyzed using one-way ANOVA Test. Results: There was significant differences in motor time and reaction time between active and control groups (pactive and passive groups except for UT without MTP and SCM (platent MTP and control groups. Furthermore, there was no significant difference in premotor times between the three groups. Conclusion: The present study shows that patients with active MTP need more time to react to stimulus, but patients with latent MTP are similar to healthy subjects in the reaction time. Patients with active MTP had less compatibility with environmental stimulations, and they responded to a specific stimulation with variability in Surface Electromyography (SEMG). PMID:26913258

  2. Correlation between neurological leg deficits and reaction time of upper limbs among low-back pain patients.

    Science.gov (United States)

    Venna, S; Hurri, H; Alaranta, H

    1994-06-01

    The purpose of the study was to examine how neurological deficits of the leg, i.e. sensory deficit, deficient reflexes and muscular weakness, correlate with reaction times of upper limbs in a group with chronic low-back pain. Thirty-two patients were studied. Three sets of measurements of simple reaction time and choice reaction time of upper limbs were conducted at one-week intervals. Neurological deficits of the leg were recorded by a physician and the subjects answered a questionnaire about the severity of their low-back symptoms (Oswestry's index). We also defined a neurological index which reflected the total sum of the three types of leg deficits experienced by each of the subjects. Sensory deficit of the leg and the neurological index correlated strongly with slower reaction times of upper limbs, while the other two neurological deficits did not reach a level of significance. Sensory deficits of the leg seem to be an indicator of much greater motor disability than has been thought so far. The motor disability not only appears distally from the lumbar radicular damage caused for example by an intervertebral herniation, it also seems to relate to psychomotor reaction more generally, even on upper limbs.

  3. Investigating the role of feedback and motivation in clinical reaction time assessment.

    Science.gov (United States)

    Eckner, James T; Chandran, Srikrishna; Richardson, James K

    2011-12-01

    To investigate the influence of performance feedback and motivation during 2 tests of simple visuomotor reaction time (RT). Cross-sectional, observational study. Outpatient academic physiatry clinic. Thirty-one healthy adults (mean [SD], 54 ± 15 years). Participants completed a clinical test of RT (RT(clin)) and a computerized test of RT with and without performance feedback (RT(compFB) and RT(compNoFB), respectively) in randomly assigned order. They then ranked their degree of motivation during each test. RT(clin) measured the time required to catch a suspended vertical shaft by hand closure after release of the shaft by the examiner. RT(compFB) and RT(compNoFB) both measured the time required to press a computer key in response to a visual cue displayed on a computer monitor. Performance feedback (visual display of the previous trial and summary results) was provided for RT(compFB), but not for RT(compNoFB). Means and standard deviations of RT(clin), RT(compFB), and RT(compNoFB) and participants' self-reported motivation on a 5-point Likert scale for each test. There were significant differences in both the means and standard deviations of RT(clin), RT(compFB), and RT(compNoFB) (F(2,60) = 81.66, P motivation between RT(clin) and RT(compFB), both of which were reported to be more motivating than RT(compNoFB). The stronger correlation between RT(clin) and RT(compFB) as well as the higher reported motivation during RT(clin) and RT(compFB) testing suggest that performance feedback is a positive motivating factor that is inherent to RT(clin) testing. RT(clin) is a simple, inexpensive technique for measuring RT and appears to be an intrinsically motivating task. This motivation may promote faster, more consistent RT performance compared with currently available computerized programs, which do not typically provide performance feedback. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  4. Measuring time of flight of fusion products in an inertial electrostatic confinement fusion device for spatial profiling of fusion reactions.

    Science.gov (United States)

    Donovan, D C; Boris, D R; Kulcinski, G L; Santarius, J F; Piefer, G R

    2013-03-01

    A new diagnostic has been developed that uses the time of flight (TOF) of the products from a nuclear fusion reaction to determine the location where the fusion reaction occurred. The TOF diagnostic uses charged particle detectors on opposing sides of the inertial electrostatic confinement (IEC) device that are coupled to high resolution timing electronics to measure the spatial profile of fusion reactions occurring between the two charged particle detectors. This diagnostic was constructed and tested by the University of Wisconsin-Madison Inertial Electrostatic Confinement Fusion Group in the IEC device, HOMER, which accelerates deuterium ions to fusion relevant energies in a high voltage (∼100 kV), spherically symmetric, electrostatic potential well [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, T. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)]. The TOF diagnostic detects the products of D(d,p)T reactions and determines where along a chord through the device the fusion event occurred. The diagnostic is also capable of using charged particle spectroscopy to determine the Doppler shift imparted to the fusion products by the center of mass energy of the fusion reactants. The TOF diagnostic is thus able to collect spatial profiles of the fusion reaction density along a chord through the device, coupled with the center of mass energy of the reactions occurring at each location. This provides levels of diagnostic detail never before achieved on an IEC device.

  5. Interference between postural control and spatial vs. non-spatial auditory reaction time tasks in older adults.

    Science.gov (United States)

    Fuhrman, Susan I; Redfern, Mark S; Jennings, J Richard; Furman, Joseph M

    2015-01-01

    This study investigated whether spatial aspects of an information processing task influence dual-task interference. Two groups (Older/Young) of healthy adults participated in dual-task experiments. Two auditory information processing tasks included a frequency discrimination choice reaction time task (non-spatial task) and a lateralization choice reaction time task (spatial task). Postural tasks included combinations of standing with eyes open or eyes closed on either a fixed floor or a sway-referenced floor. Reaction times and postural sway via center of pressure were recorded. Baseline measures of reaction time and sway were subtracted from the corresponding dual-task results to calculate reaction time task costs and postural task costs. Reaction time task cost increased with eye closure (p = 0.01), sway-referenced flooring (p < 0.0001), and the spatial task (p = 0.04). Additionally, a significant (p = 0.05) task x vision x age interaction indicated that older subjects had a significant vision X task interaction whereas young subjects did not. However, when analyzed by age group, the young group showed minimal differences in interference for the spatial and non-spatial tasks with eyes open, but showed increased interference on the spatial relative to non-spatial task with eyes closed. On the contrary, older subjects demonstrated increased interference on the spatial relative to the non-spatial task with eyes open, but not with eyes closed. These findings suggest that visual-spatial interference may occur in older subjects when vision is used to maintain posture.

  6. [Development of a real-time polymerase chain reaction method for the identification of Candida species].

    Science.gov (United States)

    Ağca, Harun; Dalyan Cilo, Burcu; Özmerdiven, Gülşah Ece; Sağlam, Sezcan; Ener, Beyza

    2015-01-01

    Candida species are one of the major causes of nosocomial infections and are the fourth most common agent involved in bloodstream infections. The impact of non-albicans Candida species is increasing, however C.albicans is still the most common species. Since the antifungal susceptibility pattern among Candida spp. may be different, rapid diagnosis and identification of non-albicans Candida spp. are important for the determination of antifungal agents that will be used for treatment. The aim of the study was to describe a real-time polymerase chain reaction (Rt-PCR) assay that rapidly detects, identifies and quantitates Candida species from blood culture samples. A total of 50 consecutive positive blood culture bottles (BACTEC, Beckton Dickinson, USA) identified at our laboratory between June-November 2013, were included in the study. Reference strains of Candida spp. (C.albicans ATCC 10231, C.glabrata ATCC 90030, C.tropicalis ATCC 1021, C.krusei ATCC 6258, C.parapsilosis ATCC 22019 and C. dubliniensis CD36) grown on Sabouraud dextrose agar were used for quality control. BACTEC bottles that were positive for Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were also studied to search the cross-reactivity. A commercial kit (Zymo Research, USA) was used for DNA extraction. Real-time PCR was performed on LightCycler 480 (Roche, Germany) with primers and probes specific for 18S rRNA of Candida species. Twenty microlitres of the reaction mix contained 2 μl of extracted DNA, 2 μl of LightCycler Fast Start DNA Master Probe (Roche Diagnostics, Germany), 2 μl of MgCl(2) (5 mmol), 2 μl of 10x PCR buffer (Roche Diagnostics, Germany), 0.5 μl of each primer (0.01 nmol/μl) and 1 μl of each probe (0.1 μmol/μl) (TibMolBiol, Germany). Amplification was performed using the following conditions; 95°C for 10 mins and 50 cycles of denaturation at 95°C for 10 secs, annealing at 62°C for 10 secs and polymerisation at 72°C for 20 secs. A melting curve was

  7. CDF-XL: computing cumulative distribution functions of reaction time data in Excel.

    Science.gov (United States)

    Houghton, George; Grange, James A

    2011-12-01

    In experimental psychology, central tendencies of reaction time (RT) distributions are used to compare different experimental conditions. This emphasis on the central tendency ignores additional information that may be derived from the RT distribution itself. One method for analysing RT distributions is to construct cumulative distribution frequency plots (CDFs; Ratcliff, Psychological Bulletin 86:446-461, 1979). However, this method is difficult to implement in widely available software, severely restricting its use. In this report, we present an Excel-based program, CDF-XL, for constructing and analysing CDFs, with the aim of making such techniques more readily accessible to researchers, including students (CDF-XL can be downloaded free of charge from the Psychonomic Society's online archive). CDF-XL functions as an Excel workbook and starts from the raw experimental data, organised into three columns (Subject, Condition, and RT) on an Input Data worksheet (a point-and-click utility is provided for achieving this format from a broader data set). No further preprocessing or sorting of the data is required. With one click of a button, CDF-XL will generate two forms of cumulative analysis: (1) "standard" CDFs, based on percentiles of participant RT distributions (by condition), and (2) a related analysis employing the participant means of rank-ordered RT bins. Both analyses involve partitioning the data in similar ways, but the first uses a "median"-type measure at the participant level, while the latter uses the mean. The results are presented in three formats: (i) by participants, suitable for entry into further statistical analysis; (ii) grand means by condition; and (iii) completed CDF plots in Excel charts.

  8. Preliminary Evidence for Reduced Post-Error Reaction Time Slowing in Hyperactive/Inattentive Preschool Children

    Science.gov (United States)

    Berwid, Olga G.; Halperin, Jeffrey M.; Johnson, Ray E.; Marks, David J.

    2013-01-01

    Background Attention-Deficit/Hyperactivity Disorder has been associated with deficits in self-regulatory cognitive processes, some of which are thought to lie at the heart of the disorder. Slowing of reaction times (RTs) for correct responses following errors made during decision tasks has been interpreted as an indication of intact self-regulatory functioning and has been shown to be attenuated in school-aged children with ADHD. This study attempted to examine whether ADHD symptoms are associated with an early-emerging deficit in post-error slowing. Method A computerized two-choice RT task was administered to an ethnically diverse sample of preschool-aged children classified as either ‘control’ (n = 120) or ‘hyperactive/inattentive’ (HI; n = 148) using parent- and teacher-rated ADHD symptoms. Analyses were conducted to determine whether HI preschoolers exhibit a deficit in this self-regulatory ability. Results HI children exhibited reduced post-error slowing relative to controls on the trials selected for analysis. Supplementary analyses indicated that this may have been due to a reduced proportion of trials following errors on which HI children slowed rather than to a reduction in the absolute magnitude of slowing on all trials following errors. Conclusions High levels of ADHD symptoms in preschoolers may be associated with a deficit in error processing as indicated by post-error slowing. The results of supplementary analyses suggest that this deficit is perhaps more a result of failures to perceive errors than of difficulties with executive control. PMID:23387525

  9. Labile sleep promotes awareness of abstract knowledge in a serial reaction time task

    Directory of Open Access Journals (Sweden)

    Roumen eKirov

    2015-09-01

    Full Text Available Sleep has been identified as a critical brain state enhancing the probability of gaining insight into covert task regularities. Both non-rapid eye movement (NREM and REM sleep have been implicated with offline re-activation and reorganization of memories supporting explicit knowledge generation. According to two-stage models of sleep function, offline processing of information during sleep is sequential requiring multiple cycles of NREM and REM sleep stages. However, the role of overnight dynamic sleep macrostructure for insightfulness has not been studied so far. In the present study, we test the hypothesis that the frequency of interactions between NREM and REM sleep stages might be critical for awareness after sleep. For that aim, the rate of sleep stage transitions was evaluated in 53 participants who learned implicitly a serial reaction time task (SRTT in which a determined sequence was inserted. The amount of explicit knowledge about the sequence was established by verbal recall after a night of sleep following SRTT learning. Polysomnography was recorded in this night and in a control night before and was analyzed to compare the rate of sleep-stage transitions between participants who did or did not gain awareness of task regularity after sleep. Indeed, individual ability of explicit knowledge generation was strongly associated with increased rate of transitions between NREM and REM sleep stages and between light sleep stages and slow wave sleep. However, the rate of NREM-REM transitions specifically predicted the amount of explicit knowledge after sleep in a trait-dependent way. These results demonstrate that enhanced lability of sleep goes along with individual ability of knowledge awareness. Observations suggest that facilitated dynamic interactions between sleep stages, particularly between NREM and REM sleep stages play a role for offline processing which promotes rule extraction and awareness.

  10. Prolongation of ERP latency and reaction time (RT) in simultaneous EEG/fMRI data acquisition.

    Science.gov (United States)

    Chun, Jinsoo; Peltier, Scott J; Yoon, Daehyun; Manschreck, Theo C; Deldin, Patricia J

    2016-08-01

    Recording EEG and fMRI data simultaneously inside a fully-operating scanner has been recognized as a novel approach in human brain research. Studies have demonstrated high concordance between the EEG signals and hemodynamic response. However, a few studies reported altered cognitive process inside the fMRI scanner such as delayed reaction time (RT) and reduced and/or delayed N100 and P300 event-related brain potential (ERP) components. The present study investigated the influence of electromagnetic field (static magnetic field, radio frequency (RF) pulse, and gradient switching) and experimental environment on posterior N100 and P300 ERP components in four different settings with six healthy subjects using a visual oddball task: (1) classic fMRI acquisition inside the scanner (e.g., supine position, mirror glasses for stimulus presentation), (2) standard behavioral experiment outside the scanner (e.g., seated position, keyboard response), (3) controlled fMRI acquisition inside the scanner (e.g., organic light-emitting diode (OLED) goggles for stimulus presentation) inside; and (4) modified behavioral experiment outside the scanner (e.g., supine position, OLED goggles). The study findings indicated that the experimental environment in simultaneous EEG/fMRI acquisition could substantially delay N1P, P300 latency, and RT inside the scanner, and was associated with a reduced N1P amplitude. There was no effect of electromagnetic field in the prolongation of RT, N1P and P300 latency inside the scanner. N1P, but not P300, latency was sensitive to stimulus presentation method inside the scanner. Future simultaneous EEG/fMRI data collection should consider experimental environment in both design and analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. The modulation of simple reaction time by the spatial probability of a visual stimulus

    Directory of Open Access Journals (Sweden)

    Carreiro L.R.R.

    2003-01-01

    Full Text Available Simple reaction time (SRT in response to visual stimuli can be influenced by many stimulus features. The speed and accuracy with which observers respond to a visual stimulus may be improved by prior knowledge about the stimulus location, which can be obtained by manipulating the spatial probability of the stimulus. However, when higher spatial probability is achieved by holding constant the stimulus location throughout successive trials, the resulting improvement in performance can also be due to local sensory facilitation caused by the recurrent spatial location of a visual target (position priming. The main objective of the present investigation was to quantitatively evaluate the modulation of SRT by the spatial probability structure of a visual stimulus. In two experiments the volunteers had to respond as quickly as possible to the visual target presented on a computer screen by pressing an optic key with the index finger of the dominant hand. Experiment 1 (N = 14 investigated how SRT changed as a function of both the different levels of spatial probability and the subject's explicit knowledge about the precise probability structure of visual stimulation. We found a gradual decrease in SRT with increasing spatial probability of a visual target regardless of the observer's previous knowledge concerning the spatial probability of the stimulus. Error rates, below 2%, were independent of the spatial probability structure of the visual stimulus, suggesting the absence of a speed-accuracy trade-off. Experiment 2 (N = 12 examined whether changes in SRT in response to a spatially recurrent visual target might be accounted for simply by sensory and temporally local facilitation. The findings indicated that the decrease in SRT brought about by a spatially recurrent target was associated with its spatial predictability, and could not be accounted for solely in terms of sensory priming.

  12. Differential effects of uninostril and alternate nostril pranayamas on cardiovascular parameters and reaction time

    Directory of Open Access Journals (Sweden)

    Ananda Balayogi Bhavanani

    2014-01-01

    Full Text Available Background: Recent studies have reported the differential physiological and psychological effects of yogic uninostril breathing (UNB and alternate nostril breathing (ANB techniques. This study aims to determine differential effects of these techniques on reaction time (RT, heart rate (HR, and blood pressure (BP. Materials and Methods: Twenty yoga-trained subjects came to the lab on six different days and RT, HR, and BP were recorded randomly before and after nine rounds of right UNB (surya nadi [SN], left UNB (chandra nadi [CN], right initiated ANB (surya bhedana [SB], left initiated ANB (chandra bhedana [CB], nadi shuddhi (NS, and normal breathing (NB. Results: Overall comparison of ∆ % changes showed statistically significant differences between groups for all parameters. There was an overall reduction in HR- and BP-based parameters following CB, CN, and NS with concurrent increases following SB and SN. The differential effects of right nostril initiated (SB and SN and left nostril initiated (CB, CN, and NS UNB and ANB techniques were clearly evidenced. Changes following NB were insignificant in all respects. The overall comparison of ∆ % changes for RT showed statistically significant differences between groups that were significantly lowered following both SB and SN. Discussion and Conclusion: Our study provides evidence of sympathomimetic effects of right nostril initiated pranayamas with sympatholytic/parasympathomimetic effect following left nostril initiated pranayamas. We suggest that the main effect of UNB and ANB techniques is determined by the nostril used for inspiration rather than that used for expiration. We conclude that right and left yogic UNB and ANB techniques have differential physiological effects that are in tune with the traditional swara yoga concept that air flow through right nostril (SN and pingala swara is activatory in nature, whereas the flow through left nostril (CN and ida swara is relaxatory.

  13. Impairment of reaction time among children awakened during stage 4 sleep.

    Science.gov (United States)

    Splaingard, Mark; Hayes, John; Smith, Gary A

    2007-01-01

    Sleep inertia refers to impairments in cognitive/motor performance and the tendency to return to sleep after awakening. As part of a project studying the effect of different types of 100 decibel (dB) sounds on awakening children during stage 4 sleep (S4S), we hypothesized that children with the greatest impairment in auditory arousal during S4S, manifested by the inability to either awaken to 100 dB sounds or successfully perform a self-rescue sequence (SRS), would have greater impairments in reaction time (RT) upon awakening than children who awoke and successfully accomplish a SRS. Observational study. Pediatric hospital-based sleep center. Healthy children aged 6-12 years. N/A. RT was measured in 44 children approximately 90 minutes before bedtime and again after awakening by either 100 dB alarms or manually during the first and second cycles of S4S. Overall, mean and median RT slowed significantly by 37% and 22%, respectively, from baseline. Slowing of RT was most evident in the youngest children (aged 6-7 years) and after awakening from the second S4S cycle. Impairments in RT were not significantly different among children who successfully awakened to the alarm and performed a SRS compared with children who did not. The degree of slowing of RT was not significantly different among children who awakened and performed an SRS compared with children who did not. The greatest slowing of RT was seen among younger children and after awakening from the second S4S cycle.

  14. Detection rates of trichomonas vaginalis, in different age groups, using real-time polymerase chain reaction.

    Science.gov (United States)

    Stemmer, Shlomo M; Adelson, Martin E; Trama, Jason P; Dorak, M Tevfik; Mordechai, Eli

    2012-10-01

    The study aimed to compare the overall detection rate of Trichomonas vaginalis to Chlamydia trachomatis and Neiserria gonorrhea and report detection rates by age groups. Real-time polymerase chain reaction was used to detect the presence of T. vaginalis, C. trachomatis, and N. gonorrhea in cervical samples obtained from patients during gynecological examinations. A total of 78,428, 119,451, and 117,494 samples from women age 12 to 75 years were retrospectively analyzed for the presence of T. vaginalis, C. trachomatis, and N. gonorrhea, respectively. T. vaginalis and C. trachomatis detection rates in Florida, New Jersey, and Texas were calculated in different age groups. The overall detection rate was 4.3% for T. vaginalis, 3.8% for C. trachomatis, and 0.6% for N. gonorrhea. The overall detection rate of T. vaginalis in Florida was 4.7% (n = 22,504), in New Jersey was 3.6% (n = 22,249), and in Texas was 4.5% (n = 33,675). Calculation of infection rates with T. vaginalis revealed differences between selected age groups with the highest detection rates in all 3 states found in age group 46 to 55 years (6.2%), which was higher than the overall detection rates in other age groups (p rate was found in age group 12 to 25 years (7.3%). The overall infection rates of T. vaginalis were higher compared with those of C. trachomatis and N. gonorrhea. Detection rates of T. vaginalis were found to be highest among women age 46 to 55 years and may be due to T. vaginalis infiltrating the subepithelial glands and being detected only during hormone-induced or antibiotic-induced changes in the vaginal flora.

  15. Severity, timing, and duration of reactions to trauma in the population: an example from Mexico.

    Science.gov (United States)

    Norris, Fran H; Murphy, Arthur D; Baker, Charlene K; Perilla, Julia L

    2003-05-01

    Normative data describing acute reactions to trauma are few. Of 2509 Mexican adults interviewed with the Composite International Diagnostic Interview, 1241 met trauma exposure criteria for index events occurring more than 1 year previously. The modal response, describing 45%, was a reaction to trauma that was mild (present but below levels of posttraumatic stress disorder symptom criteria), immediate (within the first month), and transient (over within a year). Nonetheless, 29% experienced immediate and serious reactions. Of these, 44% had chronic posttraumatic stress disorder symptoms. Those whose reactions were serious and chronic differed in many ways from those whose reactions were serious but transient. They had more traumatic events during their lives, and their index events were more likely to have occurred in childhood and to have involved violence. They had more symptoms and functional impairment after the trauma and higher levels of depressive and somatic symptoms when data were collected. Psychiatrically significant reactions to trauma persist often enough to justify their detection and treatment. Persons in need of acute intervention can be identified on the basis of the nature and severity of the initial response as well as characteristics of the stressor.

  16. Sparse Regression Based Structure Learning of Stochastic Reaction Networks from Single Cell Snapshot Time Series.

    Directory of Open Access Journals (Sweden)

    Anna Klimovskaia

    2016-12-01

    Full Text Available Stochastic chemical reaction networks constitute a model class to quantitatively describe dynamics and cell-to-cell variability in biological systems. The topology of these networks typically is only partially characterized due to experimental limitations. Current approaches for refining network topology are based on the explicit enumeration of alternative topologies and are therefore restricted to small problem instances with almost complete knowledge. We propose the reactionet lasso, a computational procedure that derives a stepwise sparse regression approach on the basis of the Chemical Master Equation, enabling large-scale structure learning for reaction networks by implicitly accounting for billions of topology variants. We have assessed the structure learning capabilities of the reactionet lasso on synthetic data for the complete TRAIL induced apoptosis signaling cascade comprising 70 reactions. We find that the reactionet lasso is able to efficiently recover the structure of these reaction systems, ab initio, with high sensitivity and specificity. With only 6000 possible reactions and over 102000 network topologies. In conjunction with information rich single cell technologies such as single cell RNA sequencing or mass cytometry, the reactionet lasso will enable large-scale structure learning, particularly in areas with partial network structure knowledge, such as cancer biology, and thereby enable the detection of pathological alterations of reaction networks. We provide software to allow for wide applicability of the reactionet lasso.

  17. Real-time monitoring of mass-transport-related enzymatic reaction kinetics in a nanochannel-array reactor.

    Science.gov (United States)

    Li, Su-Juan; Wang, Chen; Wu, Zeng-Qiang; Xu, Jing-Juan; Xia, Xing-Hua; Chen, Hong-Yuan

    2010-09-03

    To understand the fundamentals of enzymatic reactions confined in micro-/nanosystems, the construction of a small enzyme reactor coupled with an integrated real-time detection system for monitoring the kinetic information is a significant challenge. Nano-enzyme array reactors were fabricated by covalently linking enzymes to the inner channels of a porous anodic alumina (PAA) membrane. The mechanical stability of this nanodevice enables us to integrate an electrochemical detector for the real-time monitoring of the formation of the enzyme reaction product by sputtering a thin Pt film on one side of the PAA membrane. Because the enzymatic reaction is confined in a limited nanospace, the mass transport of the substrate would influence the reaction kinetics considerably. Therefore, the oxidation of glucose by dissolved oxygen catalyzed by immobilized glucose oxidase was used as a model to investigate the mass-transport-related enzymatic reaction kinetics in confined nanospaces. The activity and stability of the enzyme immobilized in the nanochannels was enhanced. In this nano-enzyme reactor, the enzymatic reaction was controlled by mass transport if the flux was low. With an increase in the flux (e.g., >50 microL min(-1)), the enzymatic reaction kinetics became the rate-determining step. This change resulted in the decrease in the conversion efficiency of the nano-enzyme reactor and the apparent Michaelis-Menten constant with an increase in substrate flux. This nanodevice integrated with an electrochemical detector could help to understand the fundamentals of enzymatic reactions confined in nanospaces and provide a platform for the design of highly efficient enzyme reactors. In addition, we believe that such nanodevices will find widespread applications in biosensing, drug screening, and biochemical synthesis.

  18. The influence of adverse reactions, subjective distress, and anxiety on retention of first-time blood donors.

    Science.gov (United States)

    van Dongen, Anne; Abraham, Charles; Ruiter, Robert A C; Veldhuizen, Ingrid J T

    2013-02-01

    This study investigated the effects of adverse events (i.e., needle reactions, fatigue, and vasovagal reactions) and feelings of distress and anxiety on retention of first-time blood donors. All effects were explored separately for men and women. First-time blood donors (n = 2438) received a questionnaire, asking them about their experience of adverse events, subjective distress, and anxiety at their first donation. Provision of a second donation was checked approximately 18 months later. After exclusion of nonresponders and donors who did not experience an adverse event, 1278 first-time donors were included in the logistic regression analyses. Nine percent of donors who experienced an adverse event at their first donation did not return for a second donation. Vasovagal reactions decreased retention in both males and females (men-odds ratio [OR], 0.45; 95% CI, 0.23-0.89; women-OR, 0.71; 95% CI, 0.51-0.98). Fatigue decreased retention in males only (OR, 0.62; 95% CI, 0.42-0.91), and subjective distress decreased retention in females only (OR, 0.77; 95% CI, 0.65-0.92). In addition to decreasing vasovagal reactions, retention interventions could productively target coping with fatigue and reducing subjective distress after adverse reactions. © 2012 American Association of Blood Banks.

  19. Study of Auditory, Visual Reaction Time and Glycemic Control (HBA1C) in Chronic Type II Diabetes Mellitus.

    Science.gov (United States)

    M, Muhil; Sembian, Umapathy; Babitha; N, Ethiya; K, Muthuselvi

    2014-09-01

    Diabetes mellitus is a disease of insulin deficiencyleads to micro and macro vascular disorder. Neuropathy is one of the major complication of chronic uncontrolled Diabetes affecting the Reaction time. To study the correlation between the glycosylated HbA1C and Auditory, visual Reaction time in chronic Type II diabetes (40-60y) of on oral hypoglycemic drugs of>10 y duration in two groups (n-100 in each group , both Males & females) and compared within the study groups and also with the age matched control group (100). HbA1C-Glycosylated HbA1C was measured by Particle enhanced immunoturbidimetric test method. Auditory and visual reaction time (ART, VRT) were measured by PC 1000 Reaction timer for control & study groups i.e. Group-I - Chronic Type II DM for >10 y with HbA1c 10 y with HbA1c > 7.0 ie impaired glycemic control. Exclusion Criteria- Subjects with Auditory and visual disturbances, alcoholism and smoking. Statistical Analysis - One-way ANOVA. Using SPSS 21 software. Both the groups had prolonged ART and VRT than controls. Among the study group, G-II (DM with HbA1C >7) had increased Auditory & Visual Reaction time than Group I which is statistically significant p-value 7 who have shown increased Auditory and Visual Reaction time than chronic DM with HbA1C<7.Severity of Peripheral neuropathy in Type II Diabetics could be due to elevated HbA1C.

  20. Co-Liquefaction of Elbistan Lignite with Manure Biomass; Part 3 - Effect of Reaction Time and Temperature

    Science.gov (United States)

    Koyunoglu, Cemil; Karaca, Hüseyin

    2017-12-01

    Most of the liquefaction process were carried out in a batch reactor, in which the residence time of the liquefaction products is long enough to favour the retrogressive reactions. To minimize retrogressive reactions, the liquefaction of coal was carried out in a flowing solvent reactor in which a fixed bed of coal is continuously permeated by hot solvent. Solvent flowing through the coal bed carries the liquefaction products out of the reactor. Unlike experiments carried out under similar conditions in a batch reactor no increase in solid residue is observed during long time high temperature runs in the flowing solvent reactor. There is a greater appreciation of the importance of retrograde, or polymerization, reactions. If the free radicals formed when coal breaks down are not quickly capped with hydrogen, they react with each other to form large molecules that are much harder to break down than the original coal. Reaction time impacts both the co-liquefaction cost and the product yield. So as to study this idea, the experiments of Elbistan Lignite (EL) with manure co-liquefaction carried out by changing the reaction time from 30 to 120 minutes. As a result, the greatest oil products yields obtained at 60 minutes. Therefore, by thinking about the oil products yield values acquired, the optimal reaction time was obtained to be 60 minutes for Elbistan lignite (EL) with manure liquefied with the temperature of 350°C and 400°C. Above 425°C did not examine because solvent (tetraline) loses its function after 425 °C. The obtained optimum temperature found 400°C due to higher total conversion of liquefaction products and also oil+gas yields.

  1. Symmetry and asymmetry of reaction time and body tissue composition of upper limbs in young female basketball players.

    Science.gov (United States)

    Poliszczuk, Tatiana; Mańkowska, Maja; Poliszczuk, Dmytro; Wiśniewski, Andrzej

    2013-01-01

    The role of psychomotor abilities and their relationship to the morphofunctional characteristics of athletes is becoming more and more emphasized in studies on the subject, especially for disciplines that require athletes to notice and to respond to signals originating in dynamically changing conditions. At the same time, athletes who perform symmetrically are more effective and less likely to sustain an injury through unilateral strain. Assessment of the degree of symmetry and asymmetry of reaction time to stimuli in the central and peripheral visual fields, and assessment of body composition of upper limbs in young female basketball players. Participants of the study comprised 17 young female basketball players. Their average age was 18.11-0.8 years. On average, they had been training basketball for 6.83-1.75 years. Body tissue composition was measured using the bioelectrical impedance method. The degree of symmetry and asymmetry of reaction time to signals in the central and peripheral visual fields were measured using the Reaction Test (RT-S1) and a modified Peripheral Perception (PP) test within the Vienna Test System. An analysis of body tissue composition of the upper right and upper left limbs found an asymmetry (p<0.01 and p<0.05) in the FAT [%], FAT MASS [kg], and FFM [kg] parameters. The values of these parameters were higher for the non-dominant arm. No statistically significant differences were found in reaction time and motor time for the dominant and non-dominant arm. A correlation was found between motor time and the FFM [kg] (r=-0.62; p<0.05) and PMM [kg] (r=-0.63; p<0.05) parameters. A significant asymmetry was found in the body tissue composition of the upper limbs. Asymmetry of reaction time was found only for signals in the peripheral visual field.

  2. Psy Toolkit: A Novel Web-Based Method for Running Online Questionnaires and Reaction-Time Experiments

    Science.gov (United States)

    Stoet, Gijsbert

    2017-01-01

    This article reviews PsyToolkit, a free web-based service designed for setting up, running, and analyzing online questionnaires and reaction-time (RT) experiments. It comes with extensive documentation, videos, lessons, and libraries of free-to-use psychological scales and RT experiments. It provides an elaborate interactive environment to use (or…

  3. Effects of amphetamine and methylphenidate on attentional performance and impulsivity in the mouse 5-Choice Serial Reaction Time Task

    DEFF Research Database (Denmark)

    Caballero Puntiverio, Maitane; Fitzpatrick, Ciarán Martin; Woldbye, David Paul Drucker

    2017-01-01

    Background: Few studies have investigated the effects of conventional attention deficit-hyperactivity disorder (ADHD) medication in the mouse 5-choice serial reaction time task (5-CSRTT), and rat studies have yielded inconsistent results. Objective: We aimed to examine the effects of acute...

  4. Persistence of the Intuitive Conception That Heavier Objects Sink More: A Reaction Time Study with Different Levels of Interference

    Science.gov (United States)

    Potvin, Patrice; Masson, Steve; Lafortune, Stéphanie; Cyr, Guillaume

    2015-01-01

    Recent research efforts have argued for the "persistence" of some of students' frequent scientific misconceptions, even after correct answers are produced. Some of these studies, based on the analysis of reaction times, have recorded latencies for counter-intuitive or incongruent stimuli compared to intuitive or congruent ones. The…

  5. A Tutorial for Analyzing Human Reaction Times: How to Filter Data, Manage Missing Values, and Choose a Statistical Model

    Science.gov (United States)

    Lachaud, Christian Michel; Renaud, Olivier

    2011-01-01

    This tutorial for the statistical processing of reaction times collected through a repeated-measure design is addressed to researchers in psychology. It aims at making explicit some important methodological issues, at orienting researchers to the existing solutions, and at providing them some evaluation tools for choosing the most robust and…

  6. Effects of Age, Intelligence and Executive Control Function on Saccadic Reaction Time in Persons with Intellectual Disabilities

    Science.gov (United States)

    Haishi, Koichi; Okuzumi, Hideyuki; Kokubun, Mitsuru

    2011-01-01

    The current research aimed to clarify the influence of age, intelligence and executive control function on the central tendency and intraindividual variability of saccadic reaction time in persons with intellectual disabilities. Participants were 44 persons with intellectual disabilities aged between 13 and 57 years whose IQs were between 14 and…

  7. Contribution of Temporal Preparation and Processing Speed to Simple Reaction Time in Persons with Alzheimer's Disease and Mild Cognitive Impairment

    Science.gov (United States)

    Sylvain-Roy, Stephanie; Bherer, Louis; Belleville, Sylvie

    2010-01-01

    Temporal preparation was assessed in 15 Alzheimer's disease (AD) patients, 20 persons with mild cognitive impairment (MCI) and 28 healthy older adults. Participants completed a simple reaction time task in which the preparatory interval duration varied randomly within two blocks (short versus long temporal window). Results indicated that AD and…

  8. Influence of intertrial interval on basal and drug-induced impulsive action in the 5-choice serial reaction time task

    DEFF Research Database (Denmark)

    Fitzpatrick, Ciaràn M; Maric, Vojislav S; Bate, Simon T

    2018-01-01

    Impulsivity is a characteristic of a number of neuropsychiatric disorders such as attention-deficit/hyperactivity disorder. The 5-choice serial reaction time task (5-CSRTT) is a rodent paradigm extensively used to assess attention and impulsivity. Notably, 5-CSRTT studies do not typically account...

  9. Quantitation of RHD by real-time polymerase chain reaction for determination of RHD zygosity and RHD mosaicism/chimerism

    DEFF Research Database (Denmark)

    Krog, Grethe Risum; Clausen, Frederik Banch; Dziegiel, Morten Hanefeld

    2007-01-01

    Determination of RHD zygosity of the spouse is crucial in preconception counseling of families with history of hemolytic disease of the fetus and newborn caused by anti-D. RHD zygosity can be determined by quantitative real-time polymerase chain reaction (PCR) basically by determining RHD dosage...

  10. Speech Planning Happens before Speech Execution: Online Reaction Time Methods in the Study of Apraxia of Speech

    Science.gov (United States)

    Maas, Edwin; Mailend, Marja-Liisa

    2012-01-01

    Purpose: The purpose of this article is to present an argument for the use of online reaction time (RT) methods to the study of apraxia of speech (AOS) and to review the existing small literature in this area and the contributions it has made to our fundamental understanding of speech planning (deficits) in AOS. Method: Following a brief…

  11. Diagnosis of ventricular drainage-related bacterial meningitis by broad-range real-time polymerase chain reaction

    DEFF Research Database (Denmark)

    Deutch, Susanna; Dahlberg, Daniel; Hedegaard, Jesper

    2007-01-01

    OBJECTIVE: To compare a broad-range real-time polymerase chain reaction (PCR) diagnostic strategy with culture to evaluate additional effects on the etiological diagnosis and the quantification of the bacterial load during the course of ventricular drainage-related bacterial meningitis (VR...

  12. Testing vaccines in human experimental malaria: statistical analysis of parasitemia measured by a quantitative real-time polymerase chain reaction.

    NARCIS (Netherlands)

    Hermsen, C.C.; Vlas, S.J. de; Gemert, G.J.A. van; Telgt, D.S.C.; Verhage, D.F.; Sauerwein, R.W.

    2004-01-01

    Clinical trials are an essential step in evaluation of safety and efficacy of malaria vaccines, and human experimental malaria infections have been used for evaluation of protective immunity of Plasmodium falciparum malaria. In this study, a quantitative real-time polymerase chain reaction was used

  13. Negativity is the main cause of reaction-time delay in an emotional Stroop study with picture/word stimuli.

    NARCIS (Netherlands)

    Sutmuller, A.D.; Brokken, D.

    2008-01-01

    The aim of this study was to find out if the emotion triggered by viewing a picture can be determined by measuring reaction times. We investigated this by using the emotional Stroop task. Emotional Stroop entails presenting two stimuli, in our case pictures and superimposed words, with different

  14. Molecular detection of the carriage rate of four intestinal protozoa with real-time polymerase chain reaction

    DEFF Research Database (Denmark)

    Efunshile, Michael A; Ngwu, Bethrand A F; Kurtzhals, Jørgen A L

    2015-01-01

    -Saharan countries. To overcome sensitivity issues related to microscopic detection and identification of cysts in stool concentrates, real-time polymerase chain reaction (PCR) was used to analyze genomic DNAs extracted from stool samples from 199 healthy school children for Entamoeba histolytica, E. dispar, Giardia...

  15. Validation of reaction time as a measure of cognitive function and quality of life in healthy subjects and patients

    DEFF Research Database (Denmark)

    Jakobsen, Lene Holm; Sorensen, Janice Marie; Rask, Ingeborg Krarup

    2011-01-01

    Malnutrition is a common problem in hospitalized patients and is related to decreased cognitive function and impaired quality of life (QoL). We investigated the validity of reaction time as a simple bedside tool for measuring cognitive function in healthy subjects and patients, and additionally...

  16. Reaction Time of Facial Affect Recognition in Asperger's Disorder for Cartoon and Real, Static and Moving Faces

    Science.gov (United States)

    Miyahara, Motohide; Bray, Anne; Tsujii, Masatsugu; Fujita, Chikako; Sugiyama, Toshiro

    2007-01-01

    This study used a choice reaction-time paradigm to test the perceived impairment of facial affect recognition in Asperger's disorder. Twenty teenagers with Asperger's disorder and 20 controls were compared with respect to the latency and accuracy of response to happy or disgusted facial expressions, presented in cartoon or real images and in…

  17. Effects of task complexity in young and old adults : Reaction time and P300 latency are not always dissociated

    NARCIS (Netherlands)

    Smulders, F.T.Y.; Kenemans, J.L.; Schmidt, W.F.; Albert, K.

    1999-01-01

    Twelve young and 11 elderly men (mean ages 21.1 and 70.1) performed a choice-reaction time (RT) task in which stimulus degradation and stimulus- response (S-R) compatibility were manipulated. The extant literature has suggested that the effects of age on RT are usually augmented (multiplicative) in

  18. DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial.

    Science.gov (United States)

    Stonehouse, Welma; Conlon, Cathryn A; Podd, John; Hill, Stephen R; Minihane, Anne M; Haskell, Crystal; Kennedy, David

    2013-05-01

    Docosahexaenoic acid (DHA) is important for brain function, and its status is dependent on dietary intakes. Therefore, individuals who consume diets low in omega-3 (n-3) polyunsaturated fatty acids may cognitively benefit from DHA supplementation. Sex and apolipoprotein E genotype (APOE) affect cognition and may modulate the response to DHA supplementation. We investigated whether a DHA supplement improves cognitive performance in healthy young adults and whether sex and APOE modulate the response. Healthy adults (n = 176; age range: 18-45 y; nonsmoking and with a low intake of DHA) completed a 6-mo randomized, placebo-controlled, double-blind intervention in which they consumed 1.16 g DHA/d or a placebo. Cognitive performance was assessed by using a computerized cognitive test battery. For all tests, z scores were calculated and clustered into cognitive domains as follows: episodic and working memory, attention, reaction time (RT) of episodic and working memory, and attention and processing speed. ANCOVA was conducted with sex and APOE as independent variables. RTs of episodic and working memory improved with DHA compared with placebo [mean difference (95% CI): -0.18 SD (-0.33, -0.03 SD) (P = 0.02) and -0.36 SD (-0.58, -0.14 SD) (P = 0.002), respectively]. Sex × treatment interactions occurred for episodic memory (P = 0.006) and the RT of working memory (P = 0.03). Compared with the placebo, DHA improved episodic memory in women [0.28 SD (0.08, 0.48 SD); P = 0.006] and RTs of working memory in men [-0.60 SD (-0.95, -0.25 SD); P = 0.001]. APOE did not affect cognitive function, but there were some indications of APOE × sex × treatment interactions. DHA supplementation improved memory and the RT of memory in healthy, young adults whose habitual diets were low in DHA. The response was modulated by sex. This trial was registered at the New Zealand Clinical Trials Registry (http://www.anzctr.org.au/default.aspx) as ACTRN12610000212055.

  19. Detection of Food Hazards in Foods: Comparison of Real Time Polymerase Chain Reaction and Cultural Methods.

    Science.gov (United States)

    Bonilauri, Paolo; Bardasi, Lia; Leonelli, Roberto; Ramini, Mattia; Luppi, Andrea; Giacometti, Federica; Merialdi, Giuseppe

    2016-01-18

    Foodstuffs should not contain microorganisms or their toxins or metabolites in quantities suggesting an unacceptable risk for human health. The detection of food hazards in foods is performed by several tests that produce results dependent on the analytical method used: an analytical reference method, defined as standard, is associated with each microbiological criterion laid down in Regulation 2073/2005/EC, but, analytical methods other than the reference ones, in particular more rapid methods, could be used. Combined screening methods performed by real time-polymerase chain reaction (RT-PCR) are currently validated as alternative methods according to the ISO 16140:2003 and certified by the Association Française de Normalisation. However, the positive results obtained with these alternative methods, the investigated molecular relations that resulted positive have to be confirmed with cultural methods using the same enrichment media in which the molecular screening was performed. Since it is necessary to assess if these testing schemes provide equivalent guarantees of food safety, the aim of this retrospective study is to analyse the data collected, from 2012 to 2014 by Emilia Romagna Region in the field of Piano Regionale Alimenti (Food Regional Plan) during official controls monitoring food samples of animal and other than animal origin. Records performed by combined methods of molecular screening of Salmonella spp., Listeria monocytogenes and thermophilic Campylobacter and cultural confirmation results were gathered together and the results were compared in order to assess the sensitivity of the methods. A total of 10,604 food samples were considered in this study: the comparison of the data revealed that the RT-PCR method detected Salmonella, L. monocytogenes, and thermophilic Campylobacter in 2.18, 3.85 and 3.73% of the samples, respectively, whereas by using cultural method these pathogens were isolated in 0.43, 1.57 and 1.57% of samples, respectively. In

  20. Amygdala fMRI Signal as a Predictor of Reaction Time

    Directory of Open Access Journals (Sweden)

    Philipp Riedel

    2016-10-01

    Full Text Available Reaction times (RT are a valuable measure for assessing cognitive processes. However, RTs are susceptible to confounds and therefore variable. Exposure to threat, for example, speeds up or slows down responses. Distinct task types to some extent account for differential effects of threat on RTs. But also do inter-individual differences like trait anxiety. In this functional magnetic resonance imaging study, we investigated whether activation within the amygdala, a brain region closely linked to the processing of threat, may also function as a predictor of RTs, similar to trait anxiety scores. After threat conditioning by means of aversive electric shocks, 45 participants performed a choice RT task during alternating 30s blocks in the presence of the threat conditioned stimulus CS+ or of the safe control stimulus CS-. Trait anxiety was assessed with the State-Trait-Anxiety-Inventory and participants were median split into a high- and a low-anxiety subgroup. We tested three hypotheses: 1 RTs will be faster during the exposure to threat compared to the safe condition in individuals with high trait anxiety. 2 The amygdala fMRI signal will be higher in the threat condition compared to the safe condition. 3 Amygdala fMRI signal prior to a RT trial will be correlated with the corresponding RT. We found that, the high-anxious subgroup showed faster responses in the threat condition compared to the safe condition, while the low-anxious subgroup showed no significant difference in RTs in the threat condition compared to the safe condition. Though the fMRI analysis did not reveal an effect of condition on amygdala activity, we found a trial-by-trial correlation between blood-oxygen-level-dependent signal within the right amygdala prior to the CRT task and the subsequent RT. Taken together, the results of this study showed that: Exposure to threat modulates task performance. This modulation is influenced by personality trait. Additionally and most

  1. Hemispheric processing differences revealed by differential conditioning and reaction time performance.

    Science.gov (United States)

    Hellige, J B

    1975-12-01

    Two different experimental procedures were used to examine (a) information-processing differences between two groups of subjects (Cs versus Vs) identified by the form of their conditioned eyeblinks; (b) information-processing differences between the right and left cerebral hemispheres; and (c) parallels between hypothesized C-V differences and right-left hemisphere differences. In the first experiment, the evocative command words BLINK and DON'T BLINK served as positive and negative conditioned stimuli. It was found that Vs gave more conditioned eyeblinks than Cs and that differential eyelid conditioning of Vs more than Cs was influenced by the semantic content of the stimuli. More importantly, the conditioning performance of Cs was more influenced by the semantic attributes of the stimuli when they were presented directly to the right visual field (left hemisphere) than when they were presented directly to the left visual field (right hemisphere). In contrast, the conditioning performance of Vs was equally influenced by the semantic attributes regardless of which hemisphere received direct stimulation. A second experiment was designed to determine whether such hemisphere-of-presentation differences for Cs versus Vs could also be obtained in a very different task. Subjects classified as Cs or Vs during a differential eyelid conditioning task then performed two same-different reaction time (RT) tasks that required discrimination of complex polygons in one case and the names of letters in another. On each RT trial both stimuli of a pair appeared briefly either in the center, left, or right visual field. For both Cs and Vs RTs to complex polygon pairs averaged 20 msec faster on left visual field trials than on right visual field trials, consistent with current hypotheses about right-hemisphere specialization for visuospatial processing. In contrast, the results for letter pairs generally confirmed the C-V differences found in Experiment 1. That is, the right visual

  2. Postexercise rehydration with beer impairs fluid retention, reaction time, and balance.

    Science.gov (United States)

    Flores-Salamanca, Rebeca; Aragón-Vargas, Luis Fernando

    2014-10-01

    Beer is promoted by popular media as a good choice for rehydration, but there is limited support for the claim. To assess the effect of beer alcohol on rehydration and motor control, 11 young (24.4 ± 3.7 years old) males of legal drinking age were dehydrated to 2.12% ± 0.20% body mass (mean ± SD) by exercising in a climatic chamber (31.7 ± 1.6 °C, 55.0% ± 8.3% relative humidity) on 3 different days, 1 week apart, and rehydrated with 100% of their sweat loss using water (WATER), 4.6% alcohol beer (BEER), or low-alcohol beer (LAB), in random order. Urine output, blood alcohol content (BAC), reaction time (RT), and balance (as measured by center of pressure velocity (VCoP)) were measured every 30 min over 3 h and compared via 2-way, repeated-measures analyses of variance (ANOVAs). After consuming ≈1.6 L in 1 h, urine output was greater for BEER (1218 ± 279 mL) than for LAB (745 ± 313 mL, p = 0.007) and WATER (774 ± 304 mL, p = 0.043). BAC remained at 0 with WATER and LAB; with BEER, BAC reached 0.857 g/L (95% confidence intervals [0.752, 0.963]) immediately postrehydration. RT was longer for BEER (0.314 ± 0.039 s) than for LAB (0.294 ± 0.034 s, p = 0.009), but was no different from WATER (0.293 ± 0.049 s, p = 0.077). VCoPx was significantly higher for BEER (0.0284 ± 0.0020 m/s) compared with LAB (0.0233 ± 0.0010 m/s) or WATER (0.0238 ± 0.0010 m/s) (p = 0.022), but VCoPy was not different among beverages. In conclusion, rehydration with BEER resulted in higher diuresis, slower RT, and impaired VCoP than rehydration with LAB or WATER.

  3. Patterns in a nonlocal time-delayed reaction-diffusion equation

    Science.gov (United States)

    Guo, Shangjiang

    2018-02-01

    In this paper, the existence, stability, and multiplicity of nontrivial (spatially homogeneous or nonhomogeneous) steady-state solution and periodic solutions for a reaction-diffusion model with nonlocal delay effect and Dirichlet/Neumann boundary condition are investigated by using Lyapunov-Schmidt reduction. Moreover, we illustrate our general results by applications to population models with one-dimensional spatial domain.

  4. Time Out: The Viewing Experience and Reactions to the 1987 NFL Players' Strike.

    Science.gov (United States)

    Walker, James R.

    The 1987 NFL players' strike provided an opportunity to evaluate the importance of media gratification and viewing involvement in the development of audience reactions to a major sports labor conflict that produced gratification denial. Two groups of viewers of professional football--183 adult males in the Memphis, Tennessee area, interviewed by…

  5. Kinetic and mechanistic studies on the Heck reaction using real-time near infrared spectroscopy

    NARCIS (Netherlands)

    Cruz, S. C.; Aarnoutse, P. J.; Rothenberg, G.; Westerhuis, J. A.; Smilde, A. K.; Bliek, A.

    2003-01-01

    In this paper, Fourier-transform near infrared (FT- NIR) spectroscopy is used to monitor the kinetics of complex catalytic reactions in liquid phase. Gas chromatography ( GC) is used as a reference method. Spectroscopic measurements generate large amounts of data and the calibration is usually

  6. Simultaneous time-resolved measurement of the reaction rates and the refractive index of photopolymerization processes

    NARCIS (Netherlands)

    Bak, Tomasz M; Beusink, J Bianca; Subramaniam, Vinod; Kanger, Johannes S

    2010-01-01

    We explore the use of imaging surface plasmon resonance (iSPR) to simultaneously measure the refractive index and reaction rates of the commercially available Ormocore photosensitive resist during photopolymerization. To this end, we adapted a commercially available iSPR device. We demonstrate good

  7. Diagnosis of foot-and mouth disease by real time reverse transcription polymerase chain reaction under field conditions in Brazil

    OpenAIRE

    Clarke Neville P; Martin Barbara M; Beckham Tammy R; Silva René R; Serra Claudia V; Barbosa Meirivan S; Reis Jorge R; Paiva Naimes O; Neta Alcina; Paixão Tatiane A; Adams L Garry; Santos Renato L

    2008-01-01

    Abstract Background Foot-and-mouth disease (FMD) is an economically important and highly contagious viral disease that affects cloven-hoofed domestic and wild animals. Virus isolation and enzyme-linked immunosorbent assay (ELISA) are the gold standard tests for diagnosis of FMD. As these methods are time consuming, assays based on viral nucleic acid amplification have been developed. Results A previously described real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay with h...

  8. The Oxford-Diamond In Situ Cell for studying chemical reactions using time-resolved X-ray diffraction.

    Science.gov (United States)

    Moorhouse, Saul J; Vranješ, Nenad; Jupe, Andrew; Drakopoulos, Michael; O'Hare, Dermot

    2012-08-01

    A versatile, infrared-heated, chemical reaction cell has been assembled and commissioned for the in situ study of a range of chemical syntheses using time-resolved energy-dispersive X-ray diffraction (EDXRD) on Beamline I12 at the Diamond Light Source. Specialized reactor configurations have been constructed to enable in situ EDXRD investigation of samples under non-ambient conditions. Chemical reactions can be studied using a range of sample vessels such as alumina crucibles, steel hydrothermal autoclaves, and glassy carbon tubes, at temperatures up to 1200 °C.

  9. The Oxford-Diamond In Situ Cell for studying chemical reactions using time-resolved X-ray diffraction

    Science.gov (United States)

    Moorhouse, Saul J.; Vranješ, Nenad; Jupe, Andrew; Drakopoulos, Michael; O'Hare, Dermot

    2012-08-01

    A versatile, infrared-heated, chemical reaction cell has been assembled and commissioned for the in situ study of a range of chemical syntheses using time-resolved energy-dispersive X-ray diffraction (EDXRD) on Beamline I12 at the Diamond Light Source. Specialized reactor configurations have been constructed to enable in situ EDXRD investigation of samples under non-ambient conditions. Chemical reactions can be studied using a range of sample vessels such as alumina crucibles, steel hydrothermal autoclaves, and glassy carbon tubes, at temperatures up to 1200 °C.

  10. Comparison of Nested Polymerase Chain Reaction and Real-Time Polymerase Chain Reaction with Parasitological Methods for Detection of Strongyloides stercoralis in Human Fecal Samples

    Science.gov (United States)

    Sharifdini, Meysam; Mirhendi, Hossein; Ashrafi, Keyhan; Hosseini, Mostafa; Mohebali, Mehdi; Khodadadi, Hossein; Kia, Eshrat Beigom

    2015-01-01

    This study was performed to evaluate nested polymerase chain reaction (PCR) and real-time PCR methods for detection of Strongyloides stercoralis in fecal samples compared with parasitological methods. A total of 466 stool samples were examined by conventional parasitological methods (formalin ether concentration [FEC] and agar plate culture [APC]). DNA was extracted using an in-house method, and mitochondrial cytochrome c oxidase subunit 1 and 18S ribosomal genes were amplified by nested PCR and real-time PCR, respectively. Among 466 samples, 12.7% and 18.2% were found infected with S. stercoralis by FEC and APC, respectively. DNA of S. stercoralis was detected in 18.9% and 25.1% of samples by real-time PCR and nested PCR, respectively. Considering parasitological methods as the diagnostic gold standard, the sensitivity and specificity of nested PCR were 100% and 91.6%, respectively, and that of real-time PCR were 84.7% and 95.8%, respectively. However, considering sequence analyzes of the selected nested PCR products, the specificity of nested PCR is increased. In general, molecular methods were superior to parasitological methods. They were more sensitive and more reliable in detection of S. stercoralis in comparison with parasitological methods. Between the two molecular methods, the sensitivity of nested PCR was higher than real-time PCR. PMID:26350449

  11. Medications influencing central cholinergic pathways affect fixation stability, saccadic response time and associated eye movement dynamics during a temporally-cued visual reaction time task.

    Science.gov (United States)

    Naicker, Preshanta; Anoopkumar-Dukie, Shailendra; Grant, Gary D; Modenese, Luca; Kavanagh, Justin J

    2017-02-01

    Anticholinergic medications largely exert their effects due to actions on the muscarinic receptor, which mediates the functions of acetylcholine in the peripheral and central nervous systems. In the central nervous system, acetylcholine plays an important role in the modulation of movement. This study investigated the effects of over-the-counter medications with varying degrees of central anticholinergic properties on fixation stability, saccadic response time and the dynamics associated with this eye movement during a temporally-cued visual reaction time task, in order to establish the significance of central cholinergic pathways in influencing eye movements during reaction time tasks. Twenty-two participants were recruited into the placebo-controlled, human double-blind, four-way crossover investigation. Eye tracking technology recorded eye movements while participants reacted to visual stimuli following temporally informative and uninformative cues. The task was performed pre-ingestion as well as 0.5 and 2 h post-ingestion of promethazine hydrochloride (strong centrally acting anticholinergic), hyoscine hydrobromide (moderate centrally acting anticholinergic), hyoscine butylbromide (anticholinergic devoid of central properties) and a placebo. Promethazine decreased fixation stability during the reaction time task. In addition, promethazine was the only drug to increase saccadic response time during temporally informative and uninformative cued trials, whereby effects on response time were more pronounced following temporally informative cues. Promethazine also decreased saccadic amplitude and increased saccadic duration during the temporally-cued reaction time task. Collectively, the results of the study highlight the significant role that central cholinergic pathways play in the control of eye movements during tasks that involve stimulus identification and motor responses following temporal cues.

  12. A Study of Correlations among Image Resolution, Reaction Time, and Extent of Motion in Remote Motor Interactions

    Directory of Open Access Journals (Sweden)

    Zoltán Rusák

    2014-01-01

    Full Text Available Motor interaction in virtual sculpting, dance trainings, and physiological rehabilitation requires close virtual proximity of users, which may be hindered by low resolution of images and system latency. This paper reports on the results of our investigation aiming to explore the pros and cons of using ultrahigh 4K resolution displays (4096 × 2160 pixels in remote motor interaction. 4K displays are able to overcome the problem of visible pixels and they are able to show more accurate image details on the level of textures, shadows, and reflections. It was our assumption that such image details can not only satisfy visual comfort of the users, but also provide detailed visual cues and improve the reaction time of users in motor interaction. To validate this hypothesis, we explored the relationships between the reaction time of subjects responding to a series of action-reaction type of games and resolution of the image used in an experiment. The results of our experiment showed that the subjects’ reaction time is significantly shorter in 4K images than in HD or VGA images in motor interaction with small motion envelope.

  13. An experiment on the factors affecting simple reaction time

    Basit reaksiyon zamanını etkileyen faktörler üzerine bir deney

    OpenAIRE

    Ufuk Türen; Burcu Kaya; Hale Akkocaoğlu

    2013-01-01

    Reaction time is considered as an important measure that affects performance of an individual both in business and private life. Especially, reaction time, which can be defined as a period of time being required for giving appropriate responses to the perceived stimuli, is an important factor in terms of efficiency of organization and also health and safety at work. Moreover, reaction time is regarded as an important factor in product design. In this study, an experiment is designed to reveal...

  14. An experiment on the factors affecting simple reaction timeBasit reaksiyon zamanını etkileyen faktörler üzerine bir deney

    OpenAIRE

    Türen, Ufuk; Kaya, Burcu; Akkocaoğlu, Hale

    2013-01-01

    Reaction time is considered as an important measure that affects performance of an individual both in business and private life. Especially, reaction time, which can be defined as a period of time being required for giving appropriate responses to the perceived stimuli, is an important factor in terms of efficiency of organization and also health and safety at work. Moreover, reaction time is regarded as an important factor in product design. In this study, an experiment is designed to reveal...

  15. Experimental and simulation studies of a real-time polymerase chain reaction in the presence of a fullerene derivative

    Energy Technology Data Exchange (ETDEWEB)

    Shang Junjun; Knap, Halina T [Department of Entomology, Soils, and Plant Sciences, Clemson University, Clemson, SC 29634-0315 (United States); Ratnikova, Tatsiana A; Ke, Pu Chun [Department of Physics and Astronomy, COMSET, Clemson University, SC 29634-0978 (United States); Anttalainen, Sini; Salonen, Emppu, E-mail: pcke11@clemson.ed, E-mail: hskrpsk@clemson.ed [Department of Applied Physics, Helsinki University of Technology, FIN-02015 TKK (Finland)

    2009-10-14

    The real-time polymerase chain reaction of the plant gene heat shock transcription factor was fully inhibited in the presence of a fullerene derivative C{sub 60}(OH){sub 20} at a concentration of 4 x 10{sup -4} mM. This inhibition was attributed to the interaction between the nanoparticle and Taq DNA polymerase in the reaction. Atomistic molecular dynamics simulations showed a clear tendency for hydrogen bonding between C{sub 60}(OH){sub 20} and both the dNTPs and ssDNA components of the polymerase chain reaction. These studies facilitate our understanding of the fate of nanoparticles in biomolecular systems, a topic of tremendous importance for addressing the biological and environmental implications of nanomaterials.

  16. The acute effects of caffeinated versus non-caffeinated alcoholic beverage on driving performance and attention/reaction time.

    Science.gov (United States)

    Howland, Jonathan; Rohsenow, Damaris J; Arnedt, J Todd; Bliss, Caleb A; Hunt, Sarah K; Calise, Tamara Vehige; Heeren, Timothy; Winter, Michael; Littlefield, Caroline; Gottlieb, Daniel J

    2011-02-01

    Marketing that promotes mixing caffeinated 'energy' drinks with alcoholic beverages (e.g. Red Bull with vodka) targets young drinkers and conveys the expectation that caffeine will offset the sedating effects of alcohol and enhance alertness. Such beliefs could result in unwarranted risk taking (e.g. driving while intoxicated). The aim of this study was to assess the acute effects of caffeinated versus non-caffeinated alcoholic beverages on a simulated driving task and attention/reaction time. We conducted a 2 × 2 between-groups randomized trial in which participants were randomized to one of four conditions: beer and non-alcoholic beer, with and without caffeine added. Caffeine was added in the same proportion as found in a commercially available caffeinated beer (69 mg/12 oz of beer at 4.8% alc. by vol). Participants were 127 non-dependent, heavy episodic, young adult drinkers (age 21-30) who were college students or recent graduates. The target breath alcohol level was 0.12 g%. Driving performance was assessed with a driving simulator; sustained attention/reaction with the Psychomotor Vigilance Task (PVT). Across the driving and attention/reaction time we found main effects for alcohol, with alcohol significantly impairing driving and sustained attention/reaction time, with mainly large statistical effects; however, the addition of caffeine had no main or interaction effects on performance. The addition of caffeine to alcohol does not appear to enhance driving or sustained attention/reaction time performance relative to alcohol alone. © 2010 The Authors, Addiction © 2010 Society for the Study of Addiction.

  17. High-throughput real-time assay based on molecular beacons for HIV-1 integrase 3'-processing reaction

    Institute of Scientific and Technical Information of China (English)

    Hong-qiu HE; Xiao-hui MA; Bin LIU; Xiao-yi ZHANG; Wei-zu CHEN; Cun-xin WANG; Shao-hui CHENG

    2007-01-01

    Aim: To develop a high-throughput real-time assay based on molecular beacons to monitor the integrase 3'-processing reaction in vitro and apply it to inhibitor screening.Methods: The recombinant human immunodeficiency virus (HIV)-1 integrase (IN) is incubated with a 38 mer oligonucleotide substrate, a sequence identical to the U5 end of HIV-1 long terminal repeats (LTR). Based on the fluores-cence properties of molecular beacons, the substrate is designed to form a stem-loop structure labeled with a fluorophore at the 5' end and a quencher at the 3'end.IN cleaves the terminal 3'-dinucleotide containing the quencher, resulting in an increase in fluorescence which can be monitored on a spectrofluorometer. To optimize this assay, tests were performed to investigate the effects of substrates, enzyme and the metal ion concentrations on the IN activity and optimal param-eters were obtained. Moreover, 2 IN inhibitors were employed to test the perfor-mance of this assay in antiviral compound screening.Results: The fluorescent intensity of the reaction mixture varies linearly with time and is proportional to the velocity of the 3'-processing reaction. Tests were performed and the results showed that the optimal rate was obtained for a reaction mixture containing 50 mg/L recom-binant HIV-1 IN, 400 nmol/L substrate, and 10 mmol/L Mn2+. The IN 3'-processing reaction under the optimal conditions showed a more than 18-fold increase in the fluorescence intensity compared to the enzyme-free control. The IC50 values of the IN inhibitors obtained in our assay were similar to the values obtained from a radiolabeled substrate assay.Conclusion: Our results demonstrated that this is a fast, reliable, and sensitive method to monitor HIV IN 3'-processing reaction and that it can be used for inhibitor screening.

  18. Directional errors of movements and their correction in a discrete tracking task. [pilot reaction time and sensorimotor performance

    Science.gov (United States)

    Jaeger, R. J.; Agarwal, G. C.; Gottlieb, G. L.

    1978-01-01

    Subjects can correct their own errors of movement more quickly than they can react to external stimuli by using three general categories of feedback: (1) knowledge of results, primarily visually mediated; (2) proprioceptive or kinaesthetic such as from muscle spindles and joint receptors, and (3) corollary discharge or efference copy within the central nervous system. The effects of these feedbacks on simple reaction time, choice reaction time, and error correction time were studied in four normal human subjects. The movement used was plantarflexion and dorsiflexion of the ankle joint. The feedback loops were modified, by changing the sign of the visual display to alter the subject's perception of results, and by applying vibration at 100 Hz simultaneously to both the agonist and antagonist muscles of the ankle joint. The central processing was interfered with when the subjects were given moderate doses of alcohol (blood alcohol concentration levels of up to 0.07%). Vibration and alcohol increase both the simple and choice reaction times but not the error correction time.

  19. Fast Adomian decomposition method for the Cauchy problem of the time-fractional reaction diffusion equation

    Directory of Open Access Journals (Sweden)

    Xiang-Chao Shi

    2016-02-01

    Full Text Available The fractional reaction diffusion equation is one of the popularly used fractional partial differential equations in recent years. The fast Adomian decomposition method is used to obtain the solution of the Cauchy problem. Also, the analytical scheme is extended to the fractional one where the Taylor series is employed. In comparison with the classical Adomian decomposition method, the ratio of the convergence is increased. The method is more reliable for the fractional partial differential equations.

  20. Development of an FTIR in situ reactor for real time study of surface reactions in photocatalysis

    Science.gov (United States)

    Hauchecorne, Birger

    For many years, photocatalysis has been proposed as one of the promising techniques to abate environmental pollutants. To improve the catalytic efficiency, it is vital to know the reaction mechanisms of the photocatalytic degradation. Different methods are therefore described in literature to study these mechanisms at the gaseous phase/photocatalyst interface with Fourier transform infrared (FTIR) spectroscopy as a commonly used method. The reactors described in literature and/or available on the market experience some technical and scientific difficulties. Generally, the catalyst can only be investigated after the reactions have occurred, or it is only possible to look at the changes in the gas phase concentrations while the reactions are taking place. It is thus a major challenge to develop a reactor which makes it possible to detect changes on the catalyst surface at the moment the reactions are happening. In this work, a new reactor is developed that makes it possible to study the catalytic surface at the moment the reactions occur, by means of transmission-absorption FTIR spectroscopy. Moreover, by using UV LEDs, it was possible to install the UV light inside the reactor area, so that no harmful UV light can leave the reactor, inherently making it a safer method. It was also opted to construct the reactor in a modular way, so that every part was interchangeable and could easily be replaced according to the needs of the researcher. A special screw cap is designed to hold the UV LEDs on a printed circuit board and to fit in every standard FTIR spectrometer. This study provides exciting new insights in the photocatalytic degradation mechanism of ethylene and acetaldehyde. It is for instance found that OH radicals are used as the oxidising agents to abate these pollutants. For ethylene it was proven that the molecular orbitals play an important role, resulting in the formation of both formaldehyde and formic acid as intermediates before complete mineralisation

  1. Studying Chemical Reactions, One Bond at a Time, with Single Molecule AFM Techniques

    Science.gov (United States)

    Fernandez, Julio M.

    2008-03-01

    The mechanisms by which mechanical forces regulate the kinetics of a chemical reaction are unknown. In my lecture I will demonstrate how we use single molecule force-clamp spectroscopy and protein engineering to study the effect of force on the kinetics of thiol/disulfide exchange. Reduction of disulfide bond via the thiol/disulfide exchange chemical reaction is crucial in regulating protein function and is of common occurrence in mechanically stressed proteins. While reduction is thought to proceed through a substitution nucleophilic bimolecular (SN2) reaction, the role of a mechanical force in modulating this chemical reaction is unknown. We apply a constant stretching force to single engineered disulfide bonds and measure their rate of reduction by dithiothreitol (DTT). We find that while the reduction rate is linearly dependent on the concentration of DTT, it is exponentially dependent on the applied force, increasing 10-fold over a 300 pN range. This result predicts that the disulfide bond lengthens by 0.34 å at the transition state of the thiol/disulfide exchange reaction. In addition to DTT, we also study the reduction of the engineered disulfide bond by the E. coli enzyme thioredoxin (Trx). Thioredoxins are enzymes that catalyze disulfide bond reduction in all organisms. As before, we apply a mechanical force in the range of 25-450 pN to the engineered disulfide bond substrate and monitor the reduction of these bonds by individual enzymes. In sharp contrast with the data obtained with DTT, we now observe two alternative forms of the catalytic reaction, the first requiring a reorientation of the substrate disulfide bond, causing a shortening of the substrate polypeptide by 0.76±0.07 å, and the second elongating the substrate disulfide bond by 0.21±0.01 å. These results support the view that the Trx active site regulates the geometry of the participating sulfur atoms, with sub-ångström precision, in order to achieve efficient catalysis. Single molecule

  2. Effect of yoga therapy on reaction time, biochemical parameters and wellness score of peri and post-menopausal diabetic patients

    Science.gov (United States)

    Madanmohan; Bhavanani, Ananda Balayogi; Dayanidy, G; Sanjay, Zeena; Basavaraddi, Ishwar V

    2012-01-01

    Background: Yogic practices may aid in the prevention and management of diabetes mellitus (DM) and reduce cardiovascular complications in the population. The present study has been undertaken to evaluate the effect of yoga therapy on reaction time, biochemical parameters and wellness score of peri and post-menopausal diabetic patients. Materials and Methods: 15 peri and post-menopausal patients receiving standard medical treatment for type 2 DM were recruited and reaction time and biochemical investigations were done before and after a comprehensive yoga therapy program comprising of three times a week sessions for six weeks. A post-intervention, retrospective wellness questionnaire compiled by ACYTER was used to evaluate the comparative feelings of the patients after the therapy program. Results: Yoga training reduced auditory reaction time (ART) from right as well as left hand, the decrease being statistically significant (PYoga improved the ‘heart friendly’ status of lipid profile in our subjects and as our participants were peri and post-menopausal, the decrease in cardiovascular risk profile is of greater significance. A comprehensive yoga therapy program has the potential to enhance the beneficial effects of standard medical management of diabetes mellitus and can be used as an effective complementary or integrative therapy program. PMID:22346060

  3. Green's-function reaction dynamics: a particle-based approach for simulating biochemical networks in time and space.

    Science.gov (United States)

    van Zon, Jeroen S; ten Wolde, Pieter Rein

    2005-12-15

    We have developed a new numerical technique, called Green's-function reaction dynamics (GFRD), that makes it possible to simulate biochemical networks at the particle level and in both time and space. In this scheme, a maximum time step is chosen such that only single particles or pairs of particles have to be considered. For these particles, the Smoluchowski equation can be solved analytically using Green's functions. The main idea of GFRD is to exploit the exact solution of the Smoluchoswki equation to set up an event-driven algorithm, which combines in one step the propagation of the particles in space with the reactions between them. The event-driven nature allows GFRD to make large jumps in time and space when the particles are far apart from each other. Here, we apply the technique to a simple model of gene expression. The simulations reveal that spatial fluctuations can be a major source of noise in biochemical networks. The calculations also show that GFRD is highly efficient. Under biologically relevant conditions, GFRD is up to five orders of magnitude faster than conventional particle-based techniques for simulating biochemical networks in time and space. GFRD is not limited to biochemical networks. It can also be applied to a large number of other reaction-diffusion problems.

  4. What speeds up the internal clock? Effects of clicks and flicker on duration judgements and reaction time.

    Science.gov (United States)

    Wearden, J H; Williams, Emily A; Jones, Luke A

    2017-03-01

    Four experiments investigated the effect of pre-stimulus events on judgements of the subjective duration of tones that they preceded. Experiments 1 to 4 used click trains, flickering squares, expanding circles, and white noise as pre-stimulus events and showed that (a) periodic clicks appeared to "speed up" the pacemaker of an internal clock but that the effect wore off over a click-free delay, (b) aperiodic click trains, and visual stimuli in the form of flickering squares and expanding circles, also produced similar increases in estimated tone duration, as did white noise, although its effect was weaker. A fifth experiment examined the effects of periodic flicker on reaction time and showed that, as with periodic clicks in a previous experiment, reaction times were shorter when preceded by flicker than without.

  5. Free-running circadian rhythms of muscle strength, reaction time, and body temperature in totally blind people

    OpenAIRE

    Squarcini, Camila Fabiana Rossi; Pires, Maria Laura Nogueira [UNESP; Lopes, Cleide; Benedito-silva, Ana AmÉlia; Esteves, Andrea Maculano; Cornelissen-guillaume, Germaine; Matarazzo, Carolina; Garcia, Danilo; Silva, Maria Stella Peccin; Tufik, Sergio; Mello, Marco TÚlio

    2013-01-01

    Light is the major synchronizer of circadian rhythms. In the absence of light, as for totally blind people, some variables, such as body temperature, have an endogenous period that is longer than 24 h and tend to be free running. However, the circadian rhythm of muscle strength and reaction time in totally blind people has not been defined in the literature. The objective of this study was to determine the period of the endogenous circadian rhythm of the isometric and isokinetic contraction s...

  6. Implementation of TTIK method and time of flight for resonance reaction studies at heavy ion accelerator DC-60

    Energy Technology Data Exchange (ETDEWEB)

    Nurmukhanbetova, A.K. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Goldberg, V.Z. [Cyclotron Institute, Texas A& M University, College Station, TX (United States); Nauruzbayev, D.K. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Saint Petersburg State University, Saint Petersburg (Russian Federation); Rogachev, G.V. [Cyclotron Institute, Texas A& M University, College Station, TX (United States); Golovkov, M.S. [Joint Institute of Nuclear Research, Dubna (Russian Federation); Dubna State University, Dubna (Russian Federation); Mynbayev, N.A. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Artemov, S.; Karakhodjaev, A. [Institute of Nuclear Physics, Tashkent (Uzbekistan); Kuterbekov, K. [L.N. Gumilov Eurasian National University, Astana (Kazakhstan); Rakhymzhanov, A. [National Laboratory Astana, Nazarbayev University, Astana 010000 (Kazakhstan); Berdibek, Zh. [School of Science and Technology, Nazarbayev University, Astana (Kazakhstan); Ivanov, I. [Institute of Nuclear Physics, Astana (Kazakhstan); Tikhonov, A. [School of Science and Technology, Nazarbayev University, Astana (Kazakhstan); Zherebchevsky, V.I.; Torilov, S. Yu. [Saint Petersburg State University, Saint Petersburg (Russian Federation); Tribble, R.E. [Cyclotron Institute, Texas A& M University, College Station, TX (United States)

    2017-03-01

    To study resonance reactions of heavy ions at low energy we have combined the Thick Target Inverse Kinematics Method (TTIK) with Time of Flight method (TF). We used extended target and TF to resolve the identification problems of various possible nuclear processes inherent to the simplest popular version of TTIK. Investigations of the {sup 15}N interaction with hydrogen and helium gas targets by using this new approach are presented.

  7. Effect of Eight Weekly Aerobic Training Program on Auditory Reaction Time and MaxVO[subscript 2] in Visual Impairments

    Science.gov (United States)

    Taskin, Cengiz

    2016-01-01

    The aim of study was to examine the effect of eight weekly aerobic exercises on auditory reaction time and MaxVO[subscript 2] in visual impairments. Forty visual impairment children that have blind 3 classification from the Turkey, experimental group; (age = 15.60 ± 1.10 years; height = 164.15 ± 4.88 cm; weight = 66.60 ± 4.77 kg) for twenty…

  8. Rapid Detection/pathotyping of Newcastle disease virus isolates in clinical samples using real time polymerase chain reaction assay

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Abdul Wajid, Muhammad Wasim, Tahir Yaqub, Shafqat F Rehmani, Tasra Bibi, Nadia Mukhtar, Javed Muhammad, Umar Bacha, Suliman Qadir Afridi, Muhammad Nauman Zahid, Zia u ddin, Muhammad Zubair Shabbir, Kamran Abbas & Muneer Ahmad ### Abstract In the present protocol we describe the real time reverse transcription polymerase chain reaction (rRT-PCR) assay for the rapid detection/pathotyping of Newcastle disease virus (NDV) isoaltes in clinical samples. Fusion gene and matrix gene...

  9. Interlaboratory validation data on real-time polymerase chain reaction detection for unauthorized genetically modified papaya line PRSV-YK

    Directory of Open Access Journals (Sweden)

    Kosuke Nakamura

    2016-06-01

    Real-time polymerase chain reaction (PCR detection method for unauthorized genetically modified (GM papaya (Carica papaya L. line PRSV-YK (PRSV-YK detection method was developed using whole genome sequence data (DDBJ Sequenced Read Archive under accession No. PRJDB3976. Interlaboratory validation datasets for PRSV-YK detection method were provided. Data indicating homogeneity of samples prepared for interlaboratory validation were included. Specificity and sensitivity test data for PRSV-YK detection method were also provided.

  10. A Flight-Calibrated Methodology for Determination of Cassini Thruster On-Times for Reaction Wheel Biases

    Science.gov (United States)

    Sarani, Siamak

    2010-01-01

    This paper describes a methodology for accurate and flight-calibrated determination of the on-times of the Cassini spacecraft Reaction Control System (RCS) thrusters, without any form of dynamic simulation, for the reaction wheel biases. The hydrazine usage and the delta V vector in body frame are also computed from the respective thruster on-times. The Cassini spacecraft, the largest and most complex interplanetary spacecraft ever built, continues to undertake ambitious and unique scientific observations of planet Saturn, Titan, Enceladus, and other moons of Saturn. In order to maintain a stable attitude during the course of its mission, this three-axis stabilized spacecraft uses two different control systems: the RCS and the reaction wheel assembly control system. The RCS is used to execute a commanded spacecraft slew, to maintain three-axis attitude control, control spacecraft's attitude while performing science observations with coarse pointing requirements, e.g. during targeted low-altitude Titan and Enceladus flybys, bias the momentum of reaction wheels, and to perform RCS-based orbit trim maneuvers. The use of RCS often imparts undesired delta V on the spacecraft. The Cassini navigation team requires accurate predictions of the delta V in spacecraft coordinates and inertial frame resulting from slews using RCS thrusters and more importantly from reaction wheel bias events. It is crucial for the Cassini spacecraft attitude control and navigation teams to be able to, quickly but accurately, predict the hydrazine usage and delta V for various reaction wheel bias events without actually having to spend time and resources simulating the event in flight software-based dynamic simulation or hardware-in-the-loop simulation environments. The methodology described in this paper, and the ground software developed thereof, are designed to provide just that. This methodology assumes a priori knowledge of thrust magnitudes and thruster pulse rise and tail-off time

  11. Effect of reaction time and polyethylene glycol monooleate-isocyanate composition on the properties of polyurethane-polysiloxane modified epoxy

    Science.gov (United States)

    Triwulandari, Evi; Ramadhan, Mohammad Kemilau; Ghozali, Muhammad

    2017-11-01

    Polyurethane-polysiloxane modified epoxy based on polyethylene glycol monooleate (PSME-PEGMO) was synthesized. Polyethylene glycol monooleate (PEGMO) for the synthesis of PSME-GMO was synthesized via esterification between oleic acid and polyethylene glycol by using sodium hydroxide as catalyst. Synthesis of PSME-PEGMO was conducted by reacting epoxy, isocyanate, PEGMO, and polysiloxane (hydrolyzed and condensable 3-glycidyloxypropyltrimethoxysilane) simultaneously in one step. This synthesis was carried out by varied the reaction time (1, 2, 3 hours), PEGMO-isocyanate composition (PI composition: 10 and 20 % toward epoxy), and isocyanate/PEGMO ratio (NCO/OH ratio: 1.5 and 2.5). Characterization of PSME-PEGMO was conducted by determining the isocyanate conversion, viscosity analysis, mechanical properties (tensile strength and elongation at break) and thermal analysis using thermogravimetric analysis (TGA). The data show that the PI composition and NCO/OH ratio does not affect the isocyanate conversion linearly. The viscosity of PSME-PEGMO product at ratio and composition variation show has tended to increase with increasing of reaction time. The highest tensile strength and elongation at break PSME-PEGMO was shown by PI composition 20%, NCO/OH ratio 2.5 and reaction time 3 hours.

  12. Synthesis and characterization of poly(glycerol citrate/sebacate); Preparacao de caracterizacao do poli(glicerol citrato/sebacato)

    Energy Technology Data Exchange (ETDEWEB)

    Brioude, Michel M.; Guimaraes, Danilo H.; Fiuza, Raigenis P.; Boaventura, Jaime S.; Jose, Nadia M., E-mail: mbrioude@gmail.com [Universidade Federal da Bahia - UFBA, Instituto de Quimica, Salvador, BA (Brazil)

    2011-07-01

    In this work were prepared and characterized the poly(glycerol citrate/sebacate) in three different ratios between acids. The polymers were prepared by a polycondensation reaction between glycerol and citric/sebacic acids and characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning differential calorimetry (DSC), scanning electron microscopy (SEM). The results showed that the polymers are polyesters and its crystallinity, thermal and morphological properties were modified by sebacic acid adding. (author)

  13. Mitigating the Hook Effect in Lateral Flow Sandwich Immunoassays Using Real-Time Reaction Kinetics.

    Science.gov (United States)

    Rey, Elizabeth G; O'Dell, Dakota; Mehta, Saurabh; Erickson, David

    2017-05-02

    The quantification of analyte concentrations using lateral flow assays is a low-cost and user-friendly alternative to traditional lab-based assays. However, sandwich-type immunoassays are often limited by the high-dose hook effect, which causes falsely low results when analytes are present at very high concentrations. In this paper, we present a reaction kinetics-based technique that solves this problem, significantly increasing the dynamic range of these devices. With the use of a traditional sandwich lateral flow immunoassay, a portable imaging device, and a mobile interface, we demonstrate the technique by quantifying C-reactive protein concentrations in human serum over a large portion of the physiological range. The technique could be applied to any hook effect-limited sandwich lateral flow assay and has a high level of accuracy even in the hook effect range.

  14. Does Occupational Exposure of Shahid Dastghieb International Airport Workers to Radiofrequency Radiation Affect Their Short Term Memory and Reaction Time?

    Directory of Open Access Journals (Sweden)

    Jarideh S.

    2015-05-01

    Full Text Available Background: Airport workers are continuously exposed to different levels of radiofrequency microwave (RF/MW radiation emitted by radar equipments. Radars are extensively used in military and aviation industries. Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI. The main goal of this study was to investigate if occupational exposure of Shahid Dastghieb international airport workers to radiofrequency radiation affects their short term memory and reaction time. Methods: Thirty two airport workers involved in duties at control and approach tower (21 males and 11 females, with the age range of 27-67 years old (mean age of 37.38, participated voluntary in this study. On the other hand, 29 workers (13 males, and 16 females whose offices were in the city with no exposure history to radar systems were also participated in this study as the control group. The employees’ reaction time and short term memory were analyzed using a standard visual reaction time (VRT test software and the modified Wechsler memory scale test, respectively. Results: The mean± SD values for the reaction times of the airport employees (N=32 and the control group (N=29 were 0.45±0.12 sec and 0.46±0.17 sec, respectively. Moreover, in the four subset tests; i.e. paired words, forward digit span, backward digit span and word recognition, the following points were obtained for the airport employees and the control group, respectively: (i pair words test: 28.00±13.13 and 32.07±11.65, (ii forward digit span: 8.38±1.40 and 9.03±1.32, (iii backward digit span: 5.54±1.87 and 6.31±1.46, and (iv word recognition: 5.73±2.36 and 6.50±1.93. These differences were not statistically significant. Conclusion: The occupational exposure of the employees to the RF radiation in Shahid

  15. Does Occupational Exposure of Shahid Dastghieb International Airport Workers to Radiofrequency Radiation Affect Their Short Term Memory and Reaction Time?

    Science.gov (United States)

    Jarideh, S; Taeb, S; Pishva, S M; Haghani, M; Sina, S; Mortazavi, S A R; Hosseini, M A; Nematollahi, S; Shokrpour, N; Hassan Shahi, M; Mortazavi, S M J

    2015-09-01

    Airport workers are continuously exposed to different levels of radiofrequency microwave (RF/MW) radiation emitted by radar equipments. Radars are extensively used in military and aviation industries. Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI. The main goal of this study was to investigate if occupational exposure of Shahid Dastghieb international airport workers to radiofrequency radiation affects their short term memory and reaction time. Thirty two airport workers involved in duties at control and approach tower (21 males and 11 females), with the age range of 27-67 years old (mean age of 37.38), participated voluntary in this study. On the other hand, 29 workers (13 males, and 16 females) whose offices were in the city with no exposure history to radar systems were also participated in this study as the control group. The employees' reaction time and short term memory were analyzed using a standard visual reaction time (VRT) test software and the modified Wechsler memory scale test, respectively. The mean± SD values for the reaction times of the airport employees (N=32) and the control group (N=29) were 0.45±0.12 sec and 0.46±0.17 sec, respectively.  Moreover, in the four subset tests; i.e. paired words, forward digit span, backward digit span and word recognition, the following points were obtained for the airport employees and the control group, respectively: (i) pair words test: 28.00±13.13 and 32.07±11.65, (ii) forward digit span: 8.38±1.40 and 9.03±1.32, (iii) backward digit span: 5.54±1.87 and 6.31±1.46, and (iv) word recognition: 5.73±2.36 and 6.50±1.93. These differences were not statistically significant. The occupational exposure of the employees to the RF radiation in Shahid Dastghieb international airport does not have any

  16. A novel quantitative real-time polymerase chain reaction method for detecting toxigenic Pasteurella multocida in nasal swabs from swine.

    Science.gov (United States)

    Scherrer, Simone; Frei, Daniel; Wittenbrink, Max Michael

    2016-12-01

    Progressive atrophic rhinitis (PAR) in pigs is caused by toxigenic Pasteurella multocida. In Switzerland, PAR is monitored by selective culture of nasal swabs and subsequent polymerase chain reaction (PCR) screening of bacterial colonies for the P. multocida toxA gene. A panel of 203 nasal swabs from a recent PAR outbreak were used to evaluate a novel quantitative real-time PCR for toxigenic P. multocida in porcine nasal swabs. In comparison to the conventional PCR with a limit of detection of 100 genome equivalents per PCR reaction, the real-time PCR had a limit of detection of 10 genome equivalents. The real-time PCR detected toxA-positive P. multocida in 101 samples (49.8%), whereas the conventional PCR was less sensitive with 90 toxA-positive samples (44.3%). In comparison to the real-time PCR, 5.4% of the toxA-positive samples revealed unevaluable results by conventional PCR. The approach of culture-coupled toxA PCR for the monitoring of PAR in pigs is substantially improved by a novel quantitative real-time PCR.

  17. Alteration of the Martian Surface Through Time: A Reaction Path Modeling Approach

    Science.gov (United States)

    Ridley, W. I.; Plumlee, G. S.; Debraal, J. D.; Reed, M. H.

    1995-09-01

    We have performed preliminary geochemical reaction path calculations [1] that attempt to model reasonable martian geologic processes under various climatic conditions postulated for Mars during its planetary evolution [2]. Weathering and fluid evaporation and freezing are discussed here. Under current Earth conditions, 25 degrees C rainwater in equilibrium with the atmosphere has a calculated pH=5.66, dissolved O2=2.5x10^-4 mole/kg, and dissolved CO2=1.3x10^-5 mole/kg. In contrast, martian rainwater in a postulated early, warm and wet climate would have lower pH,, higher dissolved CO2, and lower dissolved oxygen. For instance, in a martian atmosphere with pCO2=2.2 bar [3] and pO2=10^-5 bar, rainwater is calculated to have pH=3.96, dissolved CO2 of 7.5x10^-2 mole/kg, and dissolved O2=1.3x10^-8 mole/kg. If, under these climatic conditions, there was also extensive basaltic volcanism, then rainwater would be further modified chemically by solution of volcanic gases to form acid rain. For example, we can model this process using a Kilauea gas composition, in mole percent (H2O=57.8; HCl=0.9; SO2=17.4; CO2=21.6; H2S=0.2; H2=1.0), and assume the resultant fluid is buffered by atmospheric CO2. Addition of only 0.1 gram of gas to 1 kgram of ancient rainwater reduces the pH to 3.07 and dramatically increases dissolved SO4- (3.8x10^-4 mole/kg), H2S[aq] (1.3x10^-4 mole/kg) and Cl- (4.4x10^-5 mole/kg). Weathering minerals formed by reaction of the above fluid types with martian basalts can vary significantly depending upon initial fluid acidity and solute content. Acid rain and "normal" rain (buffered under high pCO2 conditions) initially alter martian basalt (modeled as the Chassigny parent composition [4]) to, in order of decreasing abundance: Fe-smectite (+/- ferrihydrite), Mn hydroxide, kaolinite, apatite, chalcedony at pH 5 then dolomite, calcite, K-feldspar, and dawsonite also precipitate. An important aspect of this modeling is that acid rain can produce larger volumes

  18. The Drift Diffusion Model can account for the accuracy and reaction time of value-based choices under high and low time pressure

    Directory of Open Access Journals (Sweden)

    Milica Milosavljevic

    2010-10-01

    Full Text Available An important open problem is how values are compared to make simple choices. A natural hypothesis is that the brain carries out the computations associated with the value comparisons in a manner consistent with the Drift Diffusion Model (DDM, since this model has been able to account for a large amount of data in other domains. We investigated the ability of four different versions of the DDM to explain the data in a real binary food choice task under conditions of high and low time pressure. We found that a seven-parameter version of the DDM can account for the choice and reaction time data with high-accuracy, in both the high and low time pressure conditions. The changes associated with the introduction of time pressure could be traced to changes in two key model parameters: the barrier height and the noise in the slope of the drift process.

  19. Time-evolution of dense hadronic matter in high energy heavy ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Otuka, Naohiko; Ohnishi, Akira [Hokkaido Univ., Sapporo (Japan). Dept. of Physics; Nara, Yasushi; Maruyama, Tomoyuki; Niita, Koji

    1997-05-01

    Time evolution of hadronic resonance matter in ultrarelativistic nucleus-nucleus collisions are studied in the framework of cascade models. We investigate the role of higher baryonic resonances during the time evolution of hot and dense hadronic matter at AGS energies. Although final hadronic spectrum can reproduced well with and without higher baryonic resonances, the inclusion of higher resonances is shown to prevent the temperature from going beyond 200 MeV. (author)

  20. Communication: Transition state trajectory stability determines barrier crossing rates in chemical reactions induced by time-dependent oscillating fields.

    Science.gov (United States)

    Craven, Galen T; Bartsch, Thomas; Hernandez, Rigoberto

    2014-07-28

    When a chemical reaction is driven by an external field, the transition state that the system must pass through as it changes from reactant to product--for example, an energy barrier--becomes time-dependent. We show that for periodic forcing the rate of barrier crossing can be determined through stability analysis of the non-autonomous transition state. Specifically, strong agreement is observed between the difference in the Floquet exponents describing stability of the transition state trajectory, which defines a recrossing-free dividing surface [G. T. Craven, T. Bartsch, and R. Hernandez, "Persistence of transition state structure in chemical reactions driven by fields oscillating in time," Phys. Rev. E 89, 040801(R) (2014)], and the rates calculated by simulation of ensembles of trajectories. This result opens the possibility to extract rates directly from the intrinsic stability of the transition state, even when it is time-dependent, without requiring a numerically expensive simulation of the long-time dynamics of a large ensemble of trajectories.

  1. Measurement of Peripheral Vision Reaction Time Identifies White Matter Disruption in Patients with Mild Traumatic Brain Injury.

    Science.gov (United States)

    Womack, Kyle B; Paliotta, Christopher; Strain, Jeremy F; Ho, Johnson S; Skolnick, Yosef; Lytton, William W; Turtzo, L Christine; McColl, Roderick; Diaz-Arrastia, Ramon; Bergold, Peter J

    2017-04-15

    This study examined whether peripheral vision reaction time (PVRT) in patients with mild traumatic brain injury (mTBI) correlated with white matter abnormalities in centroaxial structures and impairments in neuropsychological testing. Within 24 h after mTBI, crossed reaction times (CRT), uncrossed reaction times (URT), and crossed-uncrossed difference (CUD) were measured in 23 patients using a laptop computer that displayed visual stimuli predominantly to either the left or the right visual field of the retina. The CUD is a surrogate marker of the interhemispheric transfer time (ITT). Within 7 days after the injury, patients received a diffusion tensor-MRI (DTI) scan and a battery of neuropsychological tests. Nine uninjured control subjects received similar testing. Patients 18-50 years of age were included if they had a post-resuscitation Glasgow Coma Scale >13 and an injury mechanism compatible with mTBI. Healthy controls were either age- and gender-matched family members of the TBI patients or healthy volunteers. CUD deficits >2 standard deviations (SD) were seen in 40.9% of patients. The CUD of injured patients correlated with mean diffusivity (MD) (p < 0.001, ρ = -0.811) in the posterior corpus callosum. Patients could be stratified on the basis of CUD on the Stroop 1, Controlled Oral Word Association Test (COWAT), and the obsessive-compulsive component of the Basic Symptom Inventory tests. These studies suggest that the PVRT indirectly measures white matter integrity in the posterior corpus callosum, a brain region frequently damaged by mTBI.

  2. The Effects of Heat Stress on Selective Attention and Reaction Time among Workers of a Hot Industry: Application of Computerized Version of Stroop Test

    Directory of Open Access Journals (Sweden)

    F. Golbabaei

    2015-04-01

    .Conclusion: According to the findings in present study, heat stress causes an increase in reaction time and a decrease in selective attention. Thus, heat can be assumed as a stressor in hot work environments and the heat should be taken into account while design of job and tasks which needed selective attention or reaction time.

  3. A time-dependent quantum dynamical study of the C+(2P) + H2(D2,HD) → CH+(CD+) + H(D) reaction

    Science.gov (United States)

    Guo, Jin; Zhang, Ai Jie; Zhou, Yong; Liu, Jian Yong; Jia, Jian Feng; Wu, Hai Shun

    2017-12-01

    We present time-dependent quantum wave packet calculations for the C+(2P) + H2(D2,HD) → CH+(CD+) + H(D) reactions on the ground 12A‧ potential energy surface developed by Li et al. (2015). The reaction probabilities, the integral cross sections and the thermal rate constants were obtained. The calculated thresholds of title reactions agree well with the thermochemical endothermicities. Moreover, the calculated thermal rate constant of C+ + H2 reaction agrees well with experimental data, however, smaller than the experimental data for the C+ + HD and C+ + D2 reactions.

  4. Event timing in associative learning: from biochemical reaction dynamics to behavioural observations.

    Science.gov (United States)

    Yarali, Ayse; Nehrkorn, Johannes; Tanimoto, Hiromu; Herz, Andreas V M

    2012-01-01

    Associative learning relies on event timing. Fruit flies for example, once trained with an odour that precedes electric shock, subsequently avoid this odour (punishment learning); if, on the other hand the odour follows the shock during training, it is approached later on (relief learning). During training, an odour-induced Ca(++) signal and a shock-induced dopaminergic signal converge in the Kenyon cells, synergistically activating a Ca(++)-calmodulin-sensitive adenylate cyclase, which likely leads to the synaptic plasticity underlying the conditioned avoidance of the odour. In Aplysia, the effect of serotonin on the corresponding adenylate cyclase is bi-directionally modulated by Ca(++), depending on the relative timing of the two inputs. Using a computational approach, we quantitatively explore this biochemical property of the adenylate cyclase and show that it can generate the effect of event timing on associative learning. We overcome the shortage of behavioural data in Aplysia and biochemical data in Drosophila by combining findings from both systems.

  5. Order of stimulus presentation modulates interference in Stroop matching tasks: a reaction time study

    OpenAIRE

    Caldas, Ariane Leão; David, Isabel de Paula Antunes; Portes, Paula Martins; Portugal, Anna Carolina de Almeida; Machado-Pinheiro, Walter

    2015-01-01

    In the classic Stroop effect, the time spent to name the color of an incongruent stimulus (GREEN in blue) is longer than the time necessary to name the color of a congruent stimulus (BLUE in blue). In the “Stroop matching task”, volunteers are instructed to compare attributes of two stimuli, in which one of them is necessarily a Stroop stimulus. Our aim was to investigate whether the order of stimulus presentation can explain some contradictory results and reveal the imposition of high-order ...

  6. Time resolved bovine host reponse to virulence factors mapped in milk by selected reaction monitoring

    DEFF Research Database (Denmark)

    Bislev, Stine Lønnerup; Kusebauch, Ulrike; Codrea, Marius Cosmin

    to gram-positive and gram-negative cell wall components. The results demonstrated that the extent of protein regulation is much larger after challenge with LPS than with PGN underpinning the growing evidence that gram-negative bacteria cause a far more acute host response than gram-positive bacteria...... in milk samples from cows challenged with peptidoglycan (PGN) from the gram-positive bacteria Staphylococcus aureus and lipopolysaccharide (LPS) from the gram-negative bacteria Escherichia coli for 54 hours. This method allowed for the first time a thorough proteome analysis of the time-resolved response...

  7. Reaction time norms as measured by ruler drop method in school-going South Asian children: A cross-sectional study.

    Science.gov (United States)

    Aranha, V P; Saxena, S; Moitra, M; Narkeesh, K; Arumugam, N; Samuel, A J

    2017-01-01

    This study aimed to estimate normative range for reaction time using ruler drop method for school-going South Asian children between 6 and 12 years of age. A cross-sectional study was used to evaluate the reaction time for 204 children. Normal values for each age group were obtained. The results of multiple linear regressions showed a decrease in the reaction time values with age, and a significant change occurring between six and eight years of age. No difference in reaction time was obtained between boys and girls. Ruler drop method is an easy to use test and the results of this study provide a normative data for age groups 6-12 years ranging from 214.2ms to 248.8ms. These values can serve as a reference to screen children with delayed reaction time. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Real-time observation of intersystem crossing induced by charge recombination during bimolecular electron transfer reactions

    KAUST Repository

    Alsam, Amani Abdu

    2016-09-21

    Real-time probing of intersystem crossing (ISC) and triplet-state formation after photoinduced electron transfer (ET) is a particularly challenging task that can be achieved by time-resolved spectroscopy with broadband capability. Here, we examine the mechanism of charge separation (CS), charge recombination (CR) and ISC of bimolecular photoinduced electron transfer (PET) between poly[(9,9-di(3,3′-N,N’-trimethyl-ammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) and dicyanobenzene (DCB) using time-resolved spectroscopy. PET from PFN to DCB is confirmed by monitoring the transient absorption (TA) and infrared spectroscopic signatures for the radical ion pair (DCB─•-PFN+•). In addition, our time-resolved results clearly demonstrate that CS takes place within picoseconds followed by CR within nanoseconds. The ns-TA data exhibit the clear spectroscopic signature of PFN triplet-triplet absorption, induced by the CR of the radical ion pairs (DCB─•-PFN+•). As a result, the triplet state of PFN (3PFN*) forms and subsequently, the ground singlet state is replenished within microseconds. © 2016

  9. Extraction of ground reaction forces for real-time synthesis of walking sounds

    DEFF Research Database (Denmark)

    Serafin, Stefania; Turchet, Luca; Nordahl, Rolf

    2009-01-01

    A shoe-independent system to synthesize real-time footstep sounds on different materials has been developed. A footstep sound is considered as the result of an interaction between an exciter (the shoe) and a resonator (the floor). To achieve our goal, we propose two different solutions. The first...

  10. Reaction time to changes in the tempo of acoustic pulse trains.

    Science.gov (United States)

    Smith, R. P.; Warm, J. S.; Westendorf, D. H.

    1973-01-01

    Investigation of the ability of human observers to detect accelerations and decelerations in the rate of presentation of pulsed stimuli, i.e., changes in the tempo of acoustic pulse trains. Response times to accelerations in tempo were faster than to decelerations. Overall speed of response was inversely related to the pulse repetition rate.

  11. Temperature dependence of nuclear fission time in heavy-ion fusion-fission reactions

    Science.gov (United States)

    Eccles, Chris; Roy, Sanil; Gray, Thomas H.; Zaccone, Alessio

    2017-11-01

    Accounting for viscous damping within Fokker-Planck equations led to various improvements in the understanding and analysis of nuclear fission of heavy nuclei. Analytical expressions for the fission time are typically provided by Kramers' theory, which improves on the Bohr-Wheeler estimate by including the time scale related to many-particle dissipative processes along the deformation coordinate. However, Kramers' formula breaks down for sufficiently high excitation energies where Kramers' assumption of a large barrier no longer holds. Focusing on the overdamped regime for energies T >1 MeV, Kramers' theory should be replaced by a new analytical theory derived from the Ornstein-Uhlenbeck first-passage time method that is proposed here. The theory is applied to fission time data from fusion-fission experiments on 16O+208Pb→224Th . The proposed model provides an internally consistent one-parameter fitting of fission data with a constant nuclear friction as the fitting parameter, whereas Kramers' fitting requires a value of friction which falls out of the allowed range. The theory provides also an analytical formula that in future work can be easily implemented in numerical codes such as cascade or joanne4.

  12. Intentional and unintentional contributions to nonspecific information during reaction time foreperiods

    NARCIS (Netherlands)

    Los, S.A.; Knol, D.L.; Boers, R.M.

    2001-01-01

    The foreperiod (FP) is the interval between a warning stimulus and the imperative stimulus. It is a classical finding that both the duration and the intertrial variability of FP considerably affects response time. These effects are invariably attributed to the participant's state of nonspecific

  13. Prenatal Group B Streptococcus Test Using Real-Time Polymerase Chain Reaction

    Directory of Open Access Journals (Sweden)

    Chi-Feng Wei

    2009-06-01

    Conclusion: It is necessary to perform a GBS test 4 weeks after an initial negative GBS culture at 35–37 weeks of gestation. RT-PCR provides a simple and rapid alternative method for detecting rectovaginal GBS colonization at the time of labor.

  14. Time Required to Initiate a Defensive Reaction to Direct and Feint Attacks in Fencing.

    Science.gov (United States)

    Gutiérrez-Davila, Marcos; Rojas, F Javier; Gutiérrez-Cruz, Carmen; García, Carlos; Navarro, Enrique

    2016-12-01

    The two-fold purpose of this study was to analyze the time required by a fencer to initiate a defensive action in response to a direct attack, which involves identifying when the defending fencer detects the just-noticeable difference, and, secondly, to assess the effect that an attacker's rapid armed hand movement (feint attack) has on the time required to initiate a defensive move. Twenty-four elite fencers and a fencing master were included in the study. Four adapted force plates were installed on a scaffold used as a fencing piste. A 3D video analysis system recorded the location of 2 markers installed on the fencing master's shoulder and sword. The results confirm that the defending fencer has a mean movement time of 0.353 ± 0.028 s to perform the defensive action, which provides an advantage over the attacking fencer. The velocity of movement in the peripheral visual field has no influence on the time required by elite fencers to initiate a defensive action. This confirms the crucial role that response inhibition processes play when nonrelevant actions are perceived. Kinematic analysis of markers suggests that the eye movements of elite fencers are not the only source of information used while observing an attack.

  15. Diagnosis of foot-and mouth disease by real time reverse transcription polymerase chain reaction under field conditions in Brazil.

    Science.gov (United States)

    Paixão, Tatiane A; Neta, Alcina V Carvalho; Paiva, Naimes O; Reis, Jorge R; Barbosa, Meirivan S; Serra, Claudia V; Silva, René R; Beckham, Tammy R; Martin, Barbara M; Clarke, Neville P; Adams, L Garry; Santos, Renato L

    2008-12-31

    Foot-and-mouth disease (FMD) is an economically important and highly contagious viral disease that affects cloven-hoofed domestic and wild animals. Virus isolation and enzyme-linked immunosorbent assay (ELISA) are the gold standard tests for diagnosis of FMD. As these methods are time consuming, assays based on viral nucleic acid amplification have been developed. A previously described real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay with high sensitivity and specificity under laboratorial and experimental conditions was used in the current study. To verify the applicability of this assay under field conditions in Brazil, 460 oral swabs from cattle were collected in areas free of FMD (n = 200) and from areas with outbreaks of FMD (n = 260). Three samples from areas with outbreaks of FMD were positive by real-time RT-PCR, and 2 of those samples were positive by virus isolation and ELISA. Four other samples were considered inconclusive by real-time RT-PCR (threshold cycle [Ct] > 40); whereas all 200 samples from an area free of FMD were real-time RT-PCR negative. real-time RT-PCR is a powerful technique for reliable detection of FMDV in a fraction of the time required for virus isolation and ELISA. However, it is noteworthy that lack of infrastructure in certain areas with high risk of FMD may be a limiting factor for using real-time RT-PCR as a routine diagnostic tool.

  16. Diagnosis of foot-and mouth disease by real time reverse transcription polymerase chain reaction under field conditions in Brazil

    Directory of Open Access Journals (Sweden)

    Clarke Neville P

    2008-12-01

    Full Text Available Abstract Background Foot-and-mouth disease (FMD is an economically important and highly contagious viral disease that affects cloven-hoofed domestic and wild animals. Virus isolation and enzyme-linked immunosorbent assay (ELISA are the gold standard tests for diagnosis of FMD. As these methods are time consuming, assays based on viral nucleic acid amplification have been developed. Results A previously described real-time reverse transcriptase polymerase chain reaction (RT-PCR assay with high sensitivity and specificity under laboratorial and experimental conditions was used in the current study. To verify the applicability of this assay under field conditions in Brazil, 460 oral swabs from cattle were collected in areas free of FMD (n = 200 and from areas with outbreaks of FMD (n = 260. Three samples from areas with outbreaks of FMD were positive by real-time RT-PCR, and 2 of those samples were positive by virus isolation and ELISA. Four other samples were considered inconclusive by real-time RT-PCR (threshold cycle [Ct] > 40; whereas all 200 samples from an area free of FMD were real-time RT-PCR negative. Conclusion real-time RT-PCR is a powerful technique for reliable detection of FMDV in a fraction of the time required for virus isolation and ELISA. However, it is noteworthy that lack of infrastructure in certain areas with high risk of FMD may be a limiting factor for using real-time RT-PCR as a routine diagnostic tool.

  17. Individual Differences in Resting Corticospinal Excitability Are Correlated with Reaction Time and GABA Content in Motor Cortex.

    Science.gov (United States)

    Greenhouse, Ian; King, Maedbh; Noah, Sean; Maddock, Richard J; Ivry, Richard B

    2017-03-08

    Individuals differ in the intrinsic excitability of their corticospinal pathways and, perhaps more generally, their entire nervous system. At present, we have little understanding of the mechanisms underlying these differences and how variation in intrinsic excitability relates to behavior. Here, we examined the relationship between individual differences in intrinsic corticospinal excitability, local cortical GABA levels, and reaction time (RT) in a group of 20 healthy human adults. We measured corticospinal excitability at rest with transcranial magnetic stimulation, local concentrations of basal GABA with magnetic resonance spectroscopy, and RT with a behavioral task. All measurements were repeated in two separate sessions, and tests of reliability confirmed the presence of stable individual differences. There was a negative correlation between corticospinal excitability and RT, such that larger motor-evoked potentials (MEPs) measured at rest were associated with faster RTs. Interestingly, larger MEPs were associated with higher levels of GABA in M1, but not in three other cortical regions. Together, these results suggest that individuals with more excitable corticospinal pathways are faster to initiate planned responses and have higher levels of GABA within M1, possibly to compensate for a more excitable motor system.SIGNIFICANCE STATEMENT This study brings together physiological, behavioral, and neurochemical evidence to examine variability in the excitability of the human motor system. Previous work has focused on state-based factors (e.g., preparedness, uncertainty), with little attention given to the influence of inherent stable characteristics. Here, we examined how the excitability of the motor system relates to reaction time and the regional content of the inhibitory neurotransmitter GABA. Importantly, motor pathway excitability and GABA concentrations were measured at rest, outside a task context, providing assays of intrinsic properties of the

  18. Comparison of DNA extraction protocols for Mycobacterium Tuberculosis in diagnosis of tuberculous meningitis by real-time polymerase chain reaction

    Directory of Open Access Journals (Sweden)

    Rajeev Thakur

    2011-01-01

    Full Text Available Background: Several nucleic acid amplification techniques are available for detection of Mycobacterium tuberculosis (MTB in pulmonary and extrapulmonary samples, but insufficient data are available on the diagnostic utility of these techniques in tubercular meningitis where bacilli load is less. The success of final amplification and detection of nucleic acid depends on successful extraction of DNA from the organism. Aims: We performed this study to compare four methods of extraction of MTB DNA from cerebrospinal fluid (CSF samples so as to select one method of DNA extraction for amplification of nucleic acid from clinical samples. Materials and Methods: Four methods of extracting MTB DNA from CSF samples for testing by real-time polymerase chain reaction (PCR were compared: QIAGEN R protocol for DNA purification using QIAamp spin procedure (manual, AMPLICOR R respiratory specimen preparation kit, MagNA Pure R kit extraction, combined manual DNA extraction with automated extraction by MagNA Pure R . Real-time PCR was performed on COBAS TaqMan 48 Analyzer R with known positive and negative controls. Results: The detection limit for the combined manual and MagNA Pure R extraction protocol was found to be 100 copies of MTB DNA per reaction as against 1,000 copies of MTB DNA per reaction by the QIAGEN R , AMPLICOR R , and the MagNA Pure R extraction protocol. Conclusion: The real-time PCR assay employing the combination of manual extraction steps with MagNA Pure R extraction protocol for extraction of MTB DNA proved to be better than other extraction methods in analytical sensitivity, but could not detect less than 10 2 bacilli /ml.

  19. Detection of Listeria monocytogenes in ready-to-eat food by Step One real-time polymerase chain reaction.

    Science.gov (United States)

    Pochop, Jaroslav; Kačániová, Miroslava; Hleba, Lukáš; Lopasovský, L'ubomír; Bobková, Alica; Zeleňáková, Lucia; Stričík, Michal

    2012-01-01

    The aim of this study was to follow contamination of ready-to-eat food with Listeria monocytogenes by using the Step One real time polymerase chain reaction (PCR). We used the PrepSEQ Rapid Spin Sample Preparation Kit for isolation of DNA and MicroSEQ® Listeria monocytogenes Detection Kit for the real-time PCR performance. In 30 samples of ready-to-eat milk and meat products without incubation we detected strains of Listeria monocytogenes in five samples (swabs). Internal positive control (IPC) was positive in all samples. Our results indicated that the real-time PCR assay developed in this study could sensitively detect Listeria monocytogenes in ready-to-eat food without incubation.

  20. Finite difference/spectral approximations for the distributed order time fractional reaction-diffusion equation on an unbounded domain

    Science.gov (United States)

    Chen, Hu; Lü, Shujuan; Chen, Wenping

    2016-06-01

    The numerical approximation of the distributed order time fractional reaction-diffusion equation on a semi-infinite spatial domain is discussed in this paper. A fully discrete scheme based on finite difference method in time and spectral approximation using Laguerre functions in space is proposed. The scheme is unconditionally stable and convergent with order O (τ2 + Δα2 +N (1 - m) / 2), where τ, Δα, N, and m are the time-step size, step size in distributed-order variable, polynomial degree, and regularity in the space variable of the exact solution, respectively. A pseudospectral scheme is also proposed and analyzed. Some numerical examples are presented to demonstrate the efficiency of the proposed scheme.

  1. R/S analysis of reaction time in Neuron Type Test for human activity in civil aviation

    Science.gov (United States)

    Zhang, Hong-Yan; Kang, Ming-Cui; Li, Jing-Qiang; Liu, Hai-Tao

    2017-03-01

    Human factors become the most serious problem leading to accidents of civil aviation, which stimulates the design and analysis of Neuron Type Test (NTT) system to explore the intrinsic properties and patterns behind the behaviors of professionals and students in civil aviation. In the experiment, normal practitioners' reaction time sequences, collected from NTT, exhibit log-normal distribution approximately. We apply the χ2 test to compute the goodness-of-fit by transforming the time sequence with Box-Cox transformation to cluster practitioners. The long-term correlation of different individual practitioner's time sequence is represented by the Hurst exponent via Rescaled Range Analysis, also named by Range/Standard deviation (R/S) Analysis. The different Hurst exponent suggests the existence of different collective behavior and different intrinsic patterns of human factors in civil aviation.

  2. Real-time monitoring of viscosity changes triggered by chemical reactions using a high-speed imaging method

    Directory of Open Access Journals (Sweden)

    Wooseok Jung

    2015-09-01

    Full Text Available We present a method to monitor in real time peptide self-assembly or polymerization events. The temperature controlled modification of a previously reported splash test setup using high speed imaging enables to observe and measure rheological changes in liquid samples and can, in turn, monitor a peptide self-assembly or polymerization reaction accompanied with specific changes in solution viscosity. A series of 2 mm glass beads were dropped into an Fmoc-L3-OMe (methylated Fluorenylmethyloxycarbonyl-trileucine solution mixed with Alcalase 2.4 L (EC 3.4.21.62 or first dipped in Tetramethylethylenediamine (TEMED, a catalyst for acrylamide polymerization, then dropped into acrylamide. The resulting splashes were observed using a high speed camera. The results demonstrate that the viscosity changes of the peptide sample during the peptide self-assembly or acrylamide polymerization affect the specific shape and evolution of the splashing event. Typically, the increase in viscosity while the reaction occurs decreased the size of the splash and the amount of time for the splash to reach maximum extension from the moment for the beads to impact the sample. The ability to observe rheological changes of sample state presents the opportunity to monitor the real time dynamics of peptide self-assembly or cross-polymerization.

  3. Age-related differences in the neural correlates of trial-to-trial variations of reaction time

    Directory of Open Access Journals (Sweden)

    Nancy E. Adleman

    2016-06-01

    Full Text Available Intra-subject variation in reaction time (ISVRT is a developmentally-important phenomenon that decreases from childhood through young adulthood in parallel with the development of executive functions and networks. Prior work has shown a significant association between trial-by-trial variations in reaction time (RT and trial-by-trial variations in brain activity as measured by the blood-oxygenated level-dependent (BOLD response in functional magnetic resonance imaging (fMRI studies. It remains unclear, however, whether such “RT-BOLD” relationships vary with age. Here, we determined whether such trial-by-trial relationships vary with age in a cross-sectional design. We observed an association between age and RT-BOLD relationships in 11 clusters located in visual/occipital regions, frontal and parietal association cortex, precentral/postcentral gyrus, and thalamus. Some of these relationships were negative, reflecting increased BOLD associated with decreased RT, manifesting around the time of stimulus presentation and positive several seconds later. Critically for present purposes, all RT-BOLD relationships increased with age. Thus, RT-BOLD relationships may reflect robust, measurable changes in the brain-behavior relationship across development.

  4. Real-time mode detection of heavy ion-induced nuclear reaction products

    CERN Document Server

    Tsyganov, Yu S; Polyakov, A N; Yakushev, A B; Vakatov, V I

    2002-01-01

    Design of spectrometers of two nuclear research facilities, the Dubna Gas-filled Recoil Separator and KHIPTI is reviewed. The sources of backgrounds are discussed and techniques used to suppress these backgrounds in one-event detection experiments aimed at the synthesis of heavy elements are presented. The first system was used in 1998 in experiments on Z=114 superheavy element. We consider the possibility of detection of rare time and position correlated recoil-alpha and alpha-alpha sequences in real-time mode as basic techniques to suppress beam and target-like associated backgrounds. Fields of application of such a technique are discussed from the viewpoint of synthesis of heavy elements and by studying their chemical properties.

  5. Long-Time Behaviour of Solutions for Autonomous Evolution Hemivariational Inequality with Multidimensional “Reaction-Displacement” Law

    Directory of Open Access Journals (Sweden)

    Pavlo O. Kasyanov

    2012-01-01

    Full Text Available We consider autonomous evolution inclusions and hemivariational inequalities with nonsmooth dependence between determinative parameters of a problem. The dynamics of all weak solutions defined on the positive semiaxis of time is studied. We prove the existence of trajectory and global attractors and investigate their structure. New properties of complete trajectories are justified. We study classes of mathematical models for geophysical processes and fields containing the multidimensional “reaction-displacement” law as one of possible application. The pointwise behavior of such problem solutions on attractor is described.

  6. Strength in the lower limbs, visual contrast sensitivity, and simple reaction time predict cognition in older women.

    Science.gov (United States)

    Anstey, K J; Lord, S R; Williams, P

    1997-03-01

    The authors investigated the association between sensorimotor variables indicative of biological aging and cognition. A community sample of 202 women ages 60-86 was assessed on 5 measures of lower limb strength, visual contrast sensitivity (VisCS), and reaction time (RT). Hierarchical multiple regression revealed that the sensorimotor variables explained age-related variance in measures of reasoning and total variance in measures of reasoning after education, health, mood, and physical activity were controlled for. It is concluded that in addition to better known predictors of cognitive aging, such as RT and VisCS, lower limb strength is an important predictor of performance on cognitive tests.

  7. Investigation of an outbreak of varicella in Chandigarh, North India, using a real-time polymerase chain reaction approach

    Directory of Open Access Journals (Sweden)

    Mini P Singh

    2017-01-01

    Full Text Available Outbreaks of varicella are reported when susceptible population accumulates. This study reports a chickenpox outbreak in Burail in August 2014, wherein 20 laboratory-confirmed cases were identified by the detection of varicella zoster virus (VZV DNA and VZV IgM antibodies. The viral load between vesicular swabs and serum samples from 8 patients with active lesions was found to have good correlation and further also related with disease severity. Real-time polymerase chain reaction can be useful for early diagnosis of an outbreak and vesicular swab can be used as a less invasive sample for assessing the disease severity.

  8. Single reaction, real time RT-PCR detection of all known avian and human metapneumoviruses.

    Science.gov (United States)

    Lemaitre, E; Allée, C; Vabret, A; Eterradossi, N; Brown, P A

    2018-01-01

    Current molecular methods for the detection of avian and human metapneumovirus (AMPV, HMPV) are specifically targeted towards each virus species or individual subgroups of these. Here a broad range SYBR Green I real time RT-PCR was developed which amplified a highly conserved fragment of sequence in the N open reading frame. This method was sufficiently efficient and specific in detecting all MPVs. Its validation according to the NF U47-600 norm for the four AMPV subgroups estimated low limits of detection between 1000 and 10copies/μL, similar with detection levels described previously for real time RT-PCRs targeting specific subgroups. RNA viruses present a challenge for the design of durable molecular diagnostic test due to the rate of change in their genome sequences which can vary substantially in different areas and over time. The fact that the regions of sequence for primer hybridization in the described method have remained sufficiently conserved since the AMPV and HMPV diverged, should give the best chance of continued detection of current subgroups and of potential unknown or future emerging MPV strains. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Dissociating models of visual working memory by reaction-time distribution analysis.

    Science.gov (United States)

    Park, Hyung-Bum; Zhang, Weiwei; Hyun, Joo-Seok

    2017-02-01

    There have been heated debates on whether visual working memory (VWM) represents information in discrete-slots or a reservoir of flexible-resources. However, one key aspect of the models has gone unnoticed, the speed of processing when stored information in memory is assessed for accuracy. The present study evaluated contrasting predictions from the two models regarding the change detection decision times spent on the assessment of stored information by estimating the ex-Gaussian parameters from change detection RT distributions across different set sizes (2, 4, 6, or 8). The estimation showed that the Gaussian components μ and σ became larger as the set size increased from 2 to 4, but stayed constant as it reached 6 and 8, with an exponential component τ increasing at above-capacity set sizes. Moreover, we found that an individual's capacity limit correlates with the memory set size where the Gaussian μ reaches a plateau. These results indicate that the decision time for assessing in-memory items is constant regardless of memory set sizes whereas the time for the remaining not-in-memory items increases as the set size exceeds VWM storage capacity. The findings suggest that the discrete-slot model explains the observed RT distributions better than the flexible-resource model. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Transient modeling of non-Fickian transport and first-order reaction using continuous time random walk

    Science.gov (United States)

    Burnell, Daniel K.; Hansen, Scott K.; Xu, Jie

    2017-09-01

    Contaminants in groundwater may experience a broad spectrum of velocities and multiple rates of mass transfer between mobile and immobile zones during transport. These conditions may lead to non-Fickian plume evolution which is not well described by the advection-dispersion equation (ADE). Simultaneously, many groundwater contaminants are degraded by processes that may be modeled as first-order decay. It is now known that non-Fickian transport and reaction are intimately coupled, with reaction affecting the transport operator. However, closed-form solutions for these important scenarios have not been published for use in applications. In this paper, we present four new Green's function analytic solutions in the uncoupled, uncorrelated continuous time random walk (CTRW) framework for reactive non-Fickian transport, corresponding to the quartet of conservative tracer solutions presented by Kreft and Zuber (1978) for Fickian transport. These consider pulse injection for both resident and flux concentration combined with detection in both resident and flux concentration. A pair of solutions for resident concentration temporal pulses with detection in both flux and resident concentration is also presented. We also derive the relationship between flux and resident concentration for non-Fickian transport with first-order reaction for this CTRW formulation. An explicit discussion of employment of the new solutions to model transport with arbitrary upgradient boundary conditions as well as mobile-immobile mass transfer is then presented. Using the new solutions, we show that first-order reaction has no effect on the anomalous spatial spreading rate of concentration profiles, but produces breakthrough curves at fixed locations that appear to have been generated by Fickian transport. Under the assumption of a Pareto CTRW transition distribution, we present a variety of numerical simulations including results showing coherence of our analytic solutions and CTRW particle

  11. Unfalsifiability and mutual translatability of major modeling schemes for choice reaction time.

    Science.gov (United States)

    Jones, Matt; Dzhafarov, Ehtibar N

    2014-01-01

    [Correction Notice: An Erratum for this article was reported in Vol 121(1) of Psychological Review (see record 2014-03591-005). The link to supplemental material was missing. All versions of this article have been corrected.] Much current research on speeded choice utilizes models in which the response is triggered by a stochastic process crossing a deterministic threshold. This article focuses on 2 such model classes, 1 based on continuous-time diffusion and the other on linear ballistic accumulation (LBA). Both models assume random variability in growth rates and in other model components across trials. We show that if the form of this variability is unconstrained, the models can exactly match any possible pattern of response probabilities and response time distributions. Thus, the explanatory or predictive content of these models is determined not by their structural assumptions but, rather, by distributional assumptions (e.g., Gaussian distributions) that are traditionally regarded as implementation details. Selective influence assumptions (i.e., which experimental manipulations affect which model parameters) are shown to have no restrictive effect, except for the theoretically questionable assumption that speed-accuracy instructions do not affect growth rates. The 2nd contribution of this article concerns translation of falsifiable models between universal modeling languages. Specifically, we translate the predictions of the diffusion and LBA models (with their parametric and selective influence assumptions intact) into the Grice modeling framework, in which accumulation processes are deterministic and thresholds are random variables. The Grice framework is also known to reproduce any possible pattern of response probabilities and times, and hence it can be used as a common language for comparing models. It is found that only a few simple properties of empirical data are necessary predictions of the diffusion and LBA models. (PsycINFO Database Record (c) 2014

  12. Performance characteristics of nested polymerase chain reaction vs real-time polymerase chain reaction methods for detecting Mycobacterium tuberculosis complex in paraffin-embedded human tissues.

    Science.gov (United States)

    Seo, An Na; Park, Hyo Jin; Lee, Hye Seung; Park, Jung Ok; Chang, Ho Eun; Nam, Kyung Han; Choe, Gheeyoung; Park, Kyoung Un

    2014-09-01

    Nucleic acid amplification tests on formalin-fixed, paraffin-embedded (FFPE) tissue specimens enable Mycobacterium tuberculosis complex (MTB) detection and rapid tuberculosis diagnosis in the absence of microbiologic culture tests. We aimed to evaluate the efficacy of different polymerase chain reaction (PCR) methods for detecting Mycobacterium species in FFPE tissues. We examined 110 FFPE specimens (56 nonmycobacterial cases, 32 MTB, and 22 nontuberculous mycobacteria [NTM] determined by acid-fast bacilli [AFB] culture) to assess five PCR methods: nested PCR (N-PCR) (Seeplex MTB Nested ACE Detection; Seegene, Seoul, South Korea), an in-house real-time PCR (RT-PCR) method, and three commercial RT-PCR methods (AccuPower MTB RT-PCR [Bioneer, Seoul, Korea], artus M tuberculosis TM PCR [Qiagen, Hilden, Germany], and AdvanSure tuberculosis/NTM RT-PCR [LG Life Sciences, Seoul, Korea]). The results of N-PCR, in-house RT-PCR, and AdvanSure RT-PCR correlated well with AFB culture results (concordance rates, 94.3%, 87.5%, and 89.5%, respectively). The sensitivity of N-PCR (87.5%) was higher than that of the RT-PCR methods, although these differences were not statistically significant between N-PCR and the in-house and AdvanSure RT-PCR methods (68.8% and 80.0%, respectively). All the PCR methods had high specificities, ranging from 98.2% to 100%. Only two NTM cases were detected by AdvanSure RT-PCR, implying a very low sensitivity. Well-designed RT-PCR and N-PCR can effectively identify MTB in FFPE specimens. Copyright© by the American Society for Clinical Pathology.

  13. A farewell to brake reaction times? Kinematics-dependent brake response in naturalistic rear-end emergencies.

    Science.gov (United States)

    Markkula, Gustav; Engström, Johan; Lodin, Johan; Bärgman, Jonas; Victor, Trent

    2016-10-01

    Driver braking behavior was analyzed using time-series recordings from naturalistic rear-end conflicts (116 crashes and 241 near-crashes), including events with and without visual distraction among drivers of cars, heavy trucks, and buses. A simple piecewise linear model could be successfully fitted, per event, to the observed driver decelerations, allowing a detailed elucidation of when drivers initiated braking and how they controlled it. Most notably, it was found that, across vehicle types, driver braking behavior was strongly dependent on the urgency of the given rear-end scenario's kinematics, quantified in terms of visual looming of the lead vehicle on the driver's retina. In contrast with previous suggestions of brake reaction times (BRTs) of 1.5s or more after onset of an unexpected hazard (e.g., brake light onset), it was found here that braking could be described as typically starting less than a second after the kinematic urgency reached certain threshold levels, with even faster reactions at higher urgencies. The rate at which drivers then increased their deceleration (towards a maximum) was also highly dependent on urgency. Probability distributions are provided that quantitatively capture these various patterns of kinematics-dependent behavioral response. Possible underlying mechanisms are suggested, including looming response thresholds and neural evidence accumulation. These accounts argue that a naturalistic braking response should not be thought of as a slow reaction to some single, researcher-defined "hazard onset", but instead as a relatively fast response to the visual looming cues that build up later on in the evolving traffic scenario. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Faster Synthesis of Beta-Diketonate Ternary Europium Complexes: Elapsed Times & Reaction Yields.

    Science.gov (United States)

    Lima, Nathalia B D; Silva, Anderson I S; Gerson, P C; Gonçalves, Simone M C; Simas, Alfredo M

    2015-01-01

    β-diketonates are customary bidentate ligands in highly luminescent ternary europium complexes, such as Eu(β-diketonate)3(L)2, where L stands for a nonionic ligand. Usually, the syntheses of these complexes start by adding, to an europium salt such as EuCl3(H2O)6, three equivalents of β-diketonate ligands to form the complexes Eu(β-diketonate)3(H2O)2. The nonionic ligands are subsequently added to form the target complexes Eu(β-diketonate)3(L)2. However, the Eu(β-diketonate)3(H2O)2 intermediates are frequently both difficult and slow to purify by recrystallization, a step which usually takes a long time, varying from days to several weeks, depending on the chosen β-diketonate. In this article, we advance a novel synthetic technique which does not use Eu(β-diketonate)3(H2O)2 as an intermediate. Instead, we start by adding 4 equivalents of a monodentate nonionic ligand L straight to EuCl3(H2O)6 to form a new intermediate: EuCl3(L)4(H2O)n, with n being either 3 or 4. The advantage is that these intermediates can now be easily, quickly, and efficiently purified. The β-diketonates are then carefully added to this intermediate to form the target complexes Eu(β-diketonate)3(L)2. For the cases studied, the 20-day average elapsed time reduced to 10 days for the faster synthesis, together with an improvement in the overall yield from 42% to 69%.

  15. Comparison of foot pedal reaction time among patients with right or left hemiplegia and able-bodied controls.

    Science.gov (United States)

    Pauley, Tim; Ismail, Farooq; Boulias, Chris; Devlin, Michael; Phadke, Chetan P

    2013-01-01

    Although inpatient stroke rehabilitation provides clinicians with the opportunity to prepare patients for continuation of prestroke activities, little is known about the patients' ability to safely resume driving at the point of discharge to the community. To compare foot pedal response times of 20 stroke patients with right hemiplegia (RH) or left hemiplegia (LH) and 10 controls. A cross-sectional design was used. Response times were measured using 3 foot pedal operation techniques: (1) right-sided accelerator with right leg operating accelerator and brake, (2) right-sided accelerator with left leg operating accelerator and brake, and (3) left-sided accelerator with left leg operating accelerator and brake. Outcomes included reaction time (RT), movement time (MT), and total response time (TRT). Controls demonstrated faster RT than patients with RH (263 vs 348 ms; P < .001) or LH (316 ms; P < .05) for all conditions, as well as faster MT than patients with RH (P < .05 for all) but not LH when using the right leg (258 vs 251 ms; P = .82). Controls demonstrated faster TRT than patients with RH (P < .001 for all) but not LH when using the right leg (515 vs 553 ms; P = .44). When using the nonparetic leg, patients with LH had braking response times comparable to controls, but patients with RH demonstrated significant impairment of both the paretic and nonparetic legs.

  16. Objective assessment of drowsiness and reaction time during intermittent Ramadan fasting in young men: a case-crossover study.

    Science.gov (United States)

    Bahammam, Ahmed S; Nashwan, Samar; Hammad, Omeima; Sharif, Munir M; Pandi-Perumal, Seithikurippu R

    2013-08-12

    Ramadan fasting and its attendant lifestyle changes induce changes in the circadian rhythm and in associated physiological and metabolic functions. Previous studies that have assessed psychomotor performance during Ramadan fasting have reported conflicting results. Therefore, we designed this study to objectively assess the effects of intermittent fasting during and outside Ramadan (to control for lifestyle changes) on drowsiness, blink total duration and mean reaction time (MRT) test while controlling for potential confounders. Eight healthy volunteers with a mean age of 25.3 ± 2.9 years and a mean body mass index (BMI) of 23.4 ± 3.2 kg/m2 reported to the sleep laboratory on four occasions for polysomnography (PSG) and drowsiness and psychomotor assessments as follows: 1) adaptation; 2) 4 weeks before Ramadan while performing the Islamic fasting for 1 week (baseline fasting) (BLF); 3) 1 week before Ramadan (non-fasting baseline) (BL); and 4) during the second week of Ramadan while fasting (Ramadan). OPTALERT™ was used to objectively assess daytime drowsiness using the Johns Drowsiness Scale (JDS), and blink total duration and a visual reaction time test were used to assess MRT. Rapid eye movement (REM) sleep percentage was significantly lower at BLF (17.7 ± 8.1%) and at Ramadan (18.6 ± 10.7%) compared with BL (25.6 ± 4.8%) (p intermittent fasting has no impact on drowsiness and vigilance as measured by the JDS, total blink duration and MRT.

  17. Resting heart rate variability is associated with ex-Gaussian metrics of intra-individual reaction time variability.

    Science.gov (United States)

    Spangler, Derek P; Williams, DeWayne P; Speller, Lassiter F; Brooks, Justin R; Thayer, Julian F

    2018-02-02

    The relationships between vagally mediated heart rate variability (vmHRV) and the cognitive mechanisms underlying performance can be elucidated with ex-Gaussian modeling-an approach that quantifies two different forms of intra-individual variability (IIV) in reaction time (RT). To this end, the current study examined relations of resting vmHRV to whole-distribution and ex-Gaussian IIV. Subjects (N = 83) completed a 5-minute baseline while vmHRV (root mean square of successive differences; RMSSD) was measured. Ex-Gaussian (sigma, tau) and whole-distribution (standard deviation) estimates of IIV were derived from reaction times on a Stroop task. Resting vmHRV was found to be inversely related to tau (exponential IIV) but not to sigma (Gaussian IIV) or the whole-distribution standard deviation of RTs. Findings suggest that individuals with high vmHRV can better prevent attentional lapses but not difficulties with motor control. These findings inform the differential relationships of cardiac vagal control to the cognitive processes underlying human performance. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  18. Effects of fexofenadine and hydroxyzine on brake reaction time during car-driving with cellular phone use.

    Science.gov (United States)

    Tashiro, Manabu; Horikawa, Etsuo; Mochizuki, Hideki; Sakurada, Yumiko; Kato, Motohisa; Inokuchi, Takatoshi; Ridout, Fran; Hindmarch, Ian; Yanai, Kazuhiko

    2005-10-01

    Antihistamines are a mainstay treatment for allergic rhinitis; however, many older agents cause adverse events, including sedation and central nervous system (CNS) impairment. Research has shown sedating effects of antihistamines on driving; currently, no known study has examined whether cellular phone usage while driving further compounds impairment in individuals administered antihistamines. The aim of this study was to examine this endpoint. In a randomized, double-blind, placebo-controlled, three-way crossover study, healthy volunteers received fexofenadine HCl 120 mg, hydroxyzine HCl 30 mg and placebo. Brake reaction time (BRT) was used to examine driving performance across four conditions: driving only; driving while completing simple calculations; complex calculations; and conversing on a cellular phone. Subjective sedation assessments were also conducted. Brake reaction time with and without cellular phone usage in fexofenadine-treated subjects did not differ significantly from placebo in any condition. In contrast, hydroxyzine-treated subjects were significantly more sedated and had slower BRTs, suggesting slower hazard recognition and brake application, compared with the fexofenadine and placebo groups in all conditions. Importantly, cellular phone operation was an additive factor, increasing BRTs in hydroxyzine-treated volunteers. Fexofenadine did not impair CNS function in subjects involved in a divided attention task of driving and cellular phone operation. Copyright (c) 2005 John Wiley & Sons, Ltd.

  19. Effects of smoking abstinence on reaction time variability in smokers with and without ADHD: An ex-Gaussian analysis

    Science.gov (United States)

    Kollins, Scott H.; McClernon, F. Joseph; Epstein, Jeff N.

    2009-01-01

    Smoking abstinence differentially affects cognitive functioning in smokers with ADHD, compared to non-ADHD smokers. Alternative approaches for analyzing reaction time data from these tasks may further elucidate important group differences. Adults smoking ≥15 cigarettes with (n = 12) or without (n = 14) a diagnosis of ADHD completed a continuous performance task (CPT) during two sessions under two separate laboratory conditions—a ‘Satiated’ condition wherein participants smoked up to and during the session; and an ‘Abstinent’ condition, in which participants were abstinent overnight and during the session. Reaction time (RT) distributions from the CPT were modeled to fit an ex-Gaussian distribution. The indicator of central tendency for RT from the normal component of the RT distribution (mu) showed a main effect of Group (ADHDGaussian parameter tau, which describes the mean and standard deviation of the non-normalcomponent of thedistribution, showedsignificant effects of session (Abstinent > Satiated), Group × Session interaction (ADHD increased significantly under Abstinent condition compared to Control), and a trend toward a main effect of Group (ADHD > Control). Alternative approaches to analyzing RT data provide a more detailed description of the effects of smoking abstinence in ADHD and non-ADHD smokers and results differ from analyses using more traditional approaches. These findings have implications for understanding the neuropsychopharmacology of nicotine and nicotine withdrawal. PMID:19041198

  20. Are there right hemisphere contributions to visually-guided movement? Manipulating left hand reaction time advantages in dextrals

    Science.gov (United States)

    Carey, David P.; Otto-de Haart, E. Grace; Buckingham, Gavin; Dijkerman, H. Chris; Hargreaves, Eric L.; Goodale, Melvyn A.

    2015-01-01

    Many studies have argued for distinct but complementary contributions from each hemisphere in the control of movements to visual targets. Investigators have attempted to extend observations from patients with unilateral left- and right-hemisphere damage, to those using neurologically-intact participants, by assuming that each hand has privileged access to the contralateral hemisphere. Previous attempts to illustrate right hemispheric contributions to the control of aiming have focussed on increasing the spatial demands of an aiming task, to attenuate the typical right hand advantages, to try to enhance a left hand reaction time advantage in right-handed participants. These early attempts have not been successful. The present study circumnavigates some of the theoretical and methodological difficulties of some of the earlier experiments, by using three different tasks linked directly to specialized functions of the right hemisphere: bisecting, the gap effect, and visuospatial localization. None of these tasks were effective in reducing the magnitude of left hand reaction time advantages in right handers. Results are discussed in terms of alternatives to right hemispheric functional explanations of the effect, the one-dimensional nature of our target arrays, power and precision given the size of the left hand RT effect, and the utility of examining the proportions of participants who show these effects, rather than exclusive reliance on measures of central tendency and their associated null hypothesis significance tests. PMID:26379572