The Experts below are selected from a list of 10494 Experts worldwide ranked by ideXlab platform
Guilherme Menezes Lage - One of the best experts on this subject based on the ideXlab platform.
-
Mental practice is associated with learning the relative Timing dimension of a task.
Journal of motor behavior, 2020Co-Authors: Tércio Apolinário-souza, Bárbara De Paula Ferreira, João Roberto Ventura De Oliveira, Nathálya Gardênia De Holanda Marinho Nogueira, Joana Andrade Ramalho Pinto, Guilherme Menezes LageAbstract:Learning about the relative Timing dimension of a motor skill is enhanced by factors that promote higher response stability between trials. Conversely, learning the Absolute Timing dimension is favored by lower trial-to-trial stability. The mental practice may increase response stability during acquisition since there is a low possibility of adjustments made between trials. Thus, this study aimed to test the hypothesis that some factors that increase response stability during the acquisition phase contribute to an enhanced relative Timing dimension learning. Our hypothesis is that mental practice shows less relative Timing error than the absence of practice. A sequential key-pressing task was practiced with two goals: learn (1) relative Timing dimension and (2) Absolute Timing dimension. Participants were assigned to one of three groups: Physical, Mental, or No practice. The Physical group showed greater learning of both dimensions than the other two groups. The Mental group showed greater learning of relative Timing dimension than the No practice group. The results suggest that mental practice produces increased stability, which in turn promotes learning of the relative Timing dimension.
-
Task engagement and mental workload involved in variation and repetition of a motor skill.
Scientific reports, 2017Co-Authors: Natália Lelis-torres, Tércio Apolinário-souza, Rodolfo Novellino Benda, Herbert Ugrinowitsch, Guilherme Menezes LageAbstract:Explanatory hypotheses proposed in behavioral studies assumed that less repetitive practice schedules, such as random practice, seem to demand greater cognitive effort than more repetitive types of practice organization, such as constant. All of these hypotheses emphasize the enhanced demand to memory processes promoted by less repetitive practice schedules. In the present study, we investigated the cognitive effort involved in random and constant practice schedules with an electrophysiological approach. Twenty-one male participants practiced a sequential key-pressing task with two goals: learning the relative Timing dimension and learning the Absolute Timing dimension. Sixty trials were performed in a constant practice schedule (only one Absolute Timing goal), and sixty trials were performed in random order (three Absolute Timing goals). Two electroencephalography based measures of cognitive states were used: (a) task engagement (sensory processing and attention resources) and (b) mental workload (working memory load). The results showed that random practice induced greater cognitive effort than constant practice when task engagement was analyzed. Throughout practice, both task engagement and mental workload decreased more in the constant practice condition than in the random practice condition. The increased demand for sensory processing observed in random practice opens a new exciting field of study in practice organization.
-
The effect of constant practice in transfer tests
Motriz: Revista de Educação Física, 2017Co-Authors: Guilherme Menezes Lage, Tércio Apolinário-souza, Maicon Rodrigues Albuquerque, Leonardo L. Portes, Marcelo Da Silva Januário, Márcio Mário Vieira, Herbert UgrinowitschAbstract:BACKGROUND There is aconsensus that repetition observed in constant practice producesminimalbenefits to the transfer of learning. OBJECTIVE The purpose of this study was to investigatein 3 experiments the effects of constant practicein transfer contexts. METHODOLOGY Participants were asked during acquisition phase, in all experiments, to press four keys sequentially with different requirements of Absolute Timing in a same relative Timing structure. In the transfer tests, they were tested in a novel Absolute Timing criterion. RESULTS The results of experiment 1 and 2 showed that the relative Timing structure was maintained only when the transfer required parameter scaling close to the parameter value practiced in acquisition. The transfer parameter that is far to the parameter practiced did not affect the movement parameterization. The result of experiment 3 showed that relative Timing structure is disrupted in the transfer test when constant practice has high and low amount of practice. CONCLUSION Some specific aspects interfere in the transfer test when constant practice is experienced.
-
The primary motor cortex is associated with learning the Absolute, but not relative, Timing dimension of a task: A tDCS study
Physiology & behavior, 2016Co-Authors: Tércio Apolinário-souza, Marco Aurélio Romano-silva, Débora Marques De Miranda, Leandro Fernandes Malloy-diniz, Rodolfo Novellino Benda, Herbert Ugrinowitsch, Guilherme Menezes LageAbstract:The functional role of the primary motor cortex (M1) in the production of movement parameters, such as length, direction and force, is well known; however, whether M1 is associated with the parametric adjustments in the Absolute Timing dimension of the task remains unknown. Previous studies have not applied tasks and analyses that could separate the Absolute (variant) and relative (invariant) dimensions. We applied transcranial direct current stimulation (tDCS) to M1 before motor practice to facilitate motor learning. A sequential key-pressing task was practiced with two goals: learning the relative Timing dimension and learning the Absolute Timing dimension. All effects of the stimulation of M1 were observed only in the Absolute dimension of the task. Mainly, the stimulation was associated with better performance in the transfer test in the Absolute dimension. Taken together, our results indicate that M1 is an important area for learning the Absolute Timing dimension of a motor sequence.
-
Effects of knowledge of results frequency on the learning of generalized motor programs and parameters under conditions of constant practice.
Perceptual and motor skills, 2014Co-Authors: Maicon Rodrigues Albuquerque, Guilherme Menezes Lage, Herbert Ugrinowitsch, Umberto Cesar Corrêa, Rodolfo Novellino BendaAbstract:The present study investigated the effects of the frequency of knowledge of results (KR) on both generalized motor programs and parameters. Two experiments were conducted that compared two frequencies of KR in terms of generalized motor programs and parameters: (1) the first experiment compared the effects of KR frequency on generalized motor programs in the 100% and 50% groups; and (2) the second experiment compared the effects of reduced KR frequency on parameters in the 100% and 50% groups. In the first experiment, results showed that the 50% group exhibited smaller relative Timing errors than did the 100% group, but Absolute Timing errors in the transfer test were similar between these two groups. In the second experiment, both groups exhibited similar relative and Absolute Timing errors. These results suggested that the beneficial effects of reduced KR frequency were restricted to generalized motor programs.
M. Stuhlinger - One of the best experts on this subject based on the ideXlab platform.
-
The relative and Absolute Timing accuracy of the EPIC-pn camera on XMM-Newton, from X-ray pulsations of the Crab and other pulsars
Astronomy & Astrophysics, 2012Co-Authors: Antonio Martin-carrillo, Marcus Kirsch, Isabel Caballero, Michael Freyberg, A. Ibarra, Eckhard Kendziorra, Uwe Lammers, K. Mukerjee, G. Schönherr, M. StuhlingerAbstract:Reliable Timing calibration is essential for the accurate comparison of XMM-Newton light curves with those from other observatories, to ultimately use them to derive precise physical quantities. The XMM-Newton Timing calibration is based on pulsar analysis. However, as pulsars show both Timing noise and glitches, it is essential to monitor these calibration sources regularly. To this end, the XMM-Newton observatory performs observations twice a year of the Crab pulsar to monitor the Absolute Timing accuracy of the EPIC-pn camera in the fast Timing and Burst modes. We present the results of this monitoring campaign, comparing XMM-Newton data from the Crab pulsar (PSR B0531+21) with radio measurements. In addition, we use five pulsars (PSR J0537-69, PSR B0540-69, PSR B0833-45, PSR B1509-58 and PSR B1055-52) with periods ranging from 16 ms to 197 ms to verify the relative Timing accuracy. We analysed 38 XMM-Newton observations (0.2-12.0 keV) of the Crab taken over the first ten years of the mission and 13 observations from the five complementary pulsars. All the data were processed with the SAS, the XMM-Newton Scientific Analysis Software, version 9.0. Epoch folding techniques coupled with \chi^{2} tests were used to derive relative Timing accuracies. The Absolute Timing accuracy was determined using the Crab data and comparing the time shift between the main X-ray and radio peaks in the phase folded light curves. The relative Timing accuracy of XMM-Newton is found to be better than 10^{-8}. The strongest X-ray pulse peak precedes the corresponding radio peak by 306\pm9 \mus, which is in agreement with other high energy observatories such as Chandra, INTEGRAL and RXTE. The derived Absolute Timing accuracy from our analysis is \pm48 \mus.
-
the relative and Absolute Timing accuracy of the epic pn camera on xmm newton from x ray pulsations of the crab and other pulsars
Astronomy and Astrophysics, 2012Co-Authors: A Martincarrillo, Isabel Caballero, Michael Freyberg, A. Ibarra, Eckhard Kendziorra, Uwe Lammers, K. Mukerjee, G. Schönherr, M G F Kirsch, M. StuhlingerAbstract:Aims. Reliable Timing calibration is essential for the accurate comparison of XMM-Newton light curves with those from other observatories, to ultimately use them to derive precise physical quantities. The XMM-Newton Timing calibration is based on pulsar analysis. However, because pulsars show both Timing noise and glitches, it is essential to monitor these calibration sources regularly. To this end, the XMM-Newton observatory performs observations twice a year of the Crab pulsar to monitor the Absolute Timing accuracy of the EPIC-pn camera in the fast Timing and burst modes. We present the results of this monitoring campaign, comparing XMM-Newton data from the Crab pulsar (PSR B0531+21) with radio measurements. In addition, we use five pulsars (PSR J0537-69, PSR B0540-69, PSR B0833-45, PSR B1509-58, and PSR B1055-52) with periods ranging from 16 ms to 197 ms to verify the relative Timing accuracy. Methods. We analysed 38 XMM-Newton observations (0.2–12.0 keV) of the Crab taken over the first ten years of the mission and 13 observations from the five complementary pulsars. All data were processed with SAS, the XMM-Newton Scientific Analysis Software, version 9.0. Epoch-folding techniques coupled with χ 2 tests were used to derive relative Timing accuracies. The Absolute Timing accuracy was determined using the Crab data and comparing the time shift between the main X-ray and radio peaks in the phase-folded light curves. Results. The relative Timing accuracy of XMM-Newton is found to be better than 10 −8 . The strongest X-ray pulse peak precedes the corresponding radio peak by 306 ± 9 μs, which agrees with other high-energy observatories such as Chandra, INTEGRAL and RXTE. The derived Absolute Timing accuracy from our analysis is ±48 μs.
Arnold H. Rots - One of the best experts on this subject based on the ideXlab platform.
-
Absolute Timing of the Crab Pulsar with the Rossi X-Ray Timing Explorer
The Astrophysical Journal, 2004Co-Authors: Arnold H. Rots, Keith Jahoda, Andrew LyneAbstract:We have monitored the phase of the main X-ray pulse of the Crab pulsar with the Rossi X-Ray Timing Explorer (RXTE) for almost 8 years, since the start of the mission in 1996 January. The Absolute time of RXTE's clock is sufficiently accurate to allow this phase to be compared directly with the radio profile. Our monitoring observations of the pulsar took place bi-weekly (during the periods when it was at least 30° from the Sun), and we correlated the data with radio Timing ephemerides derived from observations made at Jodrell Bank. We have determined the phase of the X-ray main pulse for each observation with a typical error in the individual data points of 50 μs. The total ensemble is consistent with a phase that is constant over the monitoring period, with the X-ray pulse leading the radio pulse by 0.0102 ± 0.0012 periods in phase, or 344 ± 40 μs in time. The error estimate is dominated by a systematic error of 40 μs in the radio data, arising from uncertainties in the variable amount of pulse delay due to interstellar scattering and instrumental calibration. The statistical error is 0.00015 periods, or 5 μs. The separation of the main pulse and interpulse appears to be unchanging at timescales of a year or less, with an average value of 0.4001 ± 0.0002 periods. There is no apparent variation in these values with energy over the 2-30 keV range. The lag between the radio and X-ray pulses may be constant in phase (i.e., rotational in nature) or constant in time (i.e., due to a path-length difference). We are not (yet) able to distinguish between these two interpretations.
-
Rossi X-Ray Timing Explorer Absolute Timing Results for the Pulsars B1821?24 and B1509?58
The Astrophysical Journal, 1998Co-Authors: Arnold H. Rots, Keith Jahoda, Andrew Lyne, D. J. Macomb, Nobuyuki Kawai, Yoshitaka Saito, V. M. Kaspi, R. N. Manchester, Donald C. Backer, A. L. SomerAbstract:Observations with the Rossi X-Ray Timing Explorer and the Jodrell Bank, Parkes, and Green Bank telescopes have enabled us to determine the time delay between radio and X-ray pulses in the two isolated pulsars B1821-24 and B1509-58. For the former we find that the narrow X-ray and radio pulse components are close to being coincident in time, with the radio peak leading by 0.02 period (60 ± 20 μs), while the wide X-ray pulse component lags the last of the two wider radio components by about 0.08 period. For the latter pulsar we find, using the standard value for the dispersion measure, that the X-ray pulse lags the radio by about 0.27 period, with no evidence for any energy dependence in the range 2-100 keV. However, uncertainties in the history of the dispersion measure for this pulsar make a comparison to previous results difficult. It is clear that there are no perceptible variations in either the lag or the dispersion measure at timescales of a year or less.
-
rossi x ray Timing explorer Absolute Timing results for the pulsars b1821 24 and b1509 58
The Astrophysical Journal, 1998Co-Authors: Arnold H. Rots, D. J. Macomb, Nobuyuki Kawai, Yoshitaka Saito, V. M. Kaspi, K Jahoda, A G LyneAbstract:Observations with the Rossi X-Ray Timing Explorer and the Jodrell Bank, Parkes, and Green Bank telescopes have enabled us to determine the time delay between radio and X-ray pulses in the two isolated pulsars B1821-24 and B1509-58. For the former we find that the narrow X-ray and radio pulse components are close to being coincident in time, with the radio peak leading by 0.02 period (60 ± 20 μs), while the wide X-ray pulse component lags the last of the two wider radio components by about 0.08 period. For the latter pulsar we find, using the standard value for the dispersion measure, that the X-ray pulse lags the radio by about 0.27 period, with no evidence for any energy dependence in the range 2-100 keV. However, uncertainties in the history of the dispersion measure for this pulsar make a comparison to previous results difficult. It is clear that there are no perceptible variations in either the lag or the dispersion measure at timescales of a year or less.
Tércio Apolinário-souza - One of the best experts on this subject based on the ideXlab platform.
-
Mental practice is associated with learning the relative Timing dimension of a task.
Journal of motor behavior, 2020Co-Authors: Tércio Apolinário-souza, Bárbara De Paula Ferreira, João Roberto Ventura De Oliveira, Nathálya Gardênia De Holanda Marinho Nogueira, Joana Andrade Ramalho Pinto, Guilherme Menezes LageAbstract:Learning about the relative Timing dimension of a motor skill is enhanced by factors that promote higher response stability between trials. Conversely, learning the Absolute Timing dimension is favored by lower trial-to-trial stability. The mental practice may increase response stability during acquisition since there is a low possibility of adjustments made between trials. Thus, this study aimed to test the hypothesis that some factors that increase response stability during the acquisition phase contribute to an enhanced relative Timing dimension learning. Our hypothesis is that mental practice shows less relative Timing error than the absence of practice. A sequential key-pressing task was practiced with two goals: learn (1) relative Timing dimension and (2) Absolute Timing dimension. Participants were assigned to one of three groups: Physical, Mental, or No practice. The Physical group showed greater learning of both dimensions than the other two groups. The Mental group showed greater learning of relative Timing dimension than the No practice group. The results suggest that mental practice produces increased stability, which in turn promotes learning of the relative Timing dimension.
-
Task engagement and mental workload involved in variation and repetition of a motor skill.
Scientific reports, 2017Co-Authors: Natália Lelis-torres, Tércio Apolinário-souza, Rodolfo Novellino Benda, Herbert Ugrinowitsch, Guilherme Menezes LageAbstract:Explanatory hypotheses proposed in behavioral studies assumed that less repetitive practice schedules, such as random practice, seem to demand greater cognitive effort than more repetitive types of practice organization, such as constant. All of these hypotheses emphasize the enhanced demand to memory processes promoted by less repetitive practice schedules. In the present study, we investigated the cognitive effort involved in random and constant practice schedules with an electrophysiological approach. Twenty-one male participants practiced a sequential key-pressing task with two goals: learning the relative Timing dimension and learning the Absolute Timing dimension. Sixty trials were performed in a constant practice schedule (only one Absolute Timing goal), and sixty trials were performed in random order (three Absolute Timing goals). Two electroencephalography based measures of cognitive states were used: (a) task engagement (sensory processing and attention resources) and (b) mental workload (working memory load). The results showed that random practice induced greater cognitive effort than constant practice when task engagement was analyzed. Throughout practice, both task engagement and mental workload decreased more in the constant practice condition than in the random practice condition. The increased demand for sensory processing observed in random practice opens a new exciting field of study in practice organization.
-
The effect of constant practice in transfer tests
Motriz: Revista de Educação Física, 2017Co-Authors: Guilherme Menezes Lage, Tércio Apolinário-souza, Maicon Rodrigues Albuquerque, Leonardo L. Portes, Marcelo Da Silva Januário, Márcio Mário Vieira, Herbert UgrinowitschAbstract:BACKGROUND There is aconsensus that repetition observed in constant practice producesminimalbenefits to the transfer of learning. OBJECTIVE The purpose of this study was to investigatein 3 experiments the effects of constant practicein transfer contexts. METHODOLOGY Participants were asked during acquisition phase, in all experiments, to press four keys sequentially with different requirements of Absolute Timing in a same relative Timing structure. In the transfer tests, they were tested in a novel Absolute Timing criterion. RESULTS The results of experiment 1 and 2 showed that the relative Timing structure was maintained only when the transfer required parameter scaling close to the parameter value practiced in acquisition. The transfer parameter that is far to the parameter practiced did not affect the movement parameterization. The result of experiment 3 showed that relative Timing structure is disrupted in the transfer test when constant practice has high and low amount of practice. CONCLUSION Some specific aspects interfere in the transfer test when constant practice is experienced.
-
The primary motor cortex is associated with learning the Absolute, but not relative, Timing dimension of a task: A tDCS study
Physiology & behavior, 2016Co-Authors: Tércio Apolinário-souza, Marco Aurélio Romano-silva, Débora Marques De Miranda, Leandro Fernandes Malloy-diniz, Rodolfo Novellino Benda, Herbert Ugrinowitsch, Guilherme Menezes LageAbstract:The functional role of the primary motor cortex (M1) in the production of movement parameters, such as length, direction and force, is well known; however, whether M1 is associated with the parametric adjustments in the Absolute Timing dimension of the task remains unknown. Previous studies have not applied tasks and analyses that could separate the Absolute (variant) and relative (invariant) dimensions. We applied transcranial direct current stimulation (tDCS) to M1 before motor practice to facilitate motor learning. A sequential key-pressing task was practiced with two goals: learning the relative Timing dimension and learning the Absolute Timing dimension. All effects of the stimulation of M1 were observed only in the Absolute dimension of the task. Mainly, the stimulation was associated with better performance in the transfer test in the Absolute dimension. Taken together, our results indicate that M1 is an important area for learning the Absolute Timing dimension of a motor sequence.
Jean-pierre Roques - One of the best experts on this subject based on the ideXlab platform.
-
Absolute Timing of the crab pulsar with the integral spi telescope
The Astrophysical Journal, 2010Co-Authors: S. Molkov, Elisabeth Jourdain, Jean-pierre RoquesAbstract:We have investigated the pulse shape evolution of the Crab pulsar emission in the hard X-ray domain of the electromagnetic spectrum. In particular, we have studied the alignment of the Crab pulsar phase profiles measured in the hard X-rays and in other wavebands. To obtain the hard X-ray pulse profiles, we have used six years (2003-2009, with a total exposure of about 4 Ms) of publicly available data of the SPI telescope on-board the International Gamma-Ray Astrophysics Laboratory observatory, folded with the pulsar time solution derived from the Jodrell Bank Crab Pulsar Monthly Ephemeris. We found that the main pulse in the hard X-ray 20-100 keV energy band leads the radio one by 8.18 ± 0.46 milliperiods in phase, or 275 ± 15 μs in time. Quoted errors represent only statistical uncertainties. Our systematic error is estimated to be ~40 μs and is mainly caused by the radio measurement uncertainties. In hard X-rays, the average distance between the main pulse and interpulse on the phase plane is 0.3989 ± 0.0009. To compare our findings in hard X-rays with the soft 2-20 keV X-ray band, we have used data of quasi-simultaneous Crab observations with the proportional counter array monitor on-board the Rossi X-Ray Timing Explorer mission. The time lag and the pulses separation values measured in the 3-20 keV band are 0.00933 ± 0.00016 (corresponding to 310 ± 6 μs) and 0.40016 ± 0.00028 parts of the cycle, respectively. While the pulse separation values measured in soft X-rays and hard X-rays agree, the time lags are statistically different. Additional analysis show that the delay between the radio and X-ray signals varies with energy in the 2-300 keV energy range. We explain such a behavior as due to the superposition of two independent components responsible for the Crab pulsed emission in this energy band.
-
Absolute Timing of the Crab pulsar with the INTEGRAL/SPI telescope
The Astrophysical Journal, 2009Co-Authors: S. Molkov, Elisabeth Jourdain, Jean-pierre RoquesAbstract:We have investigated the pulse shape evolution of the Crab pulsar emission in the hard X-ray domain of the electromagnetic spectrum. In particular, we have studied the alignment of the Crab pulsar phase profiles measured in the hard X-rays and in other wavebands. To obtain the hard X-ray pulse profiles, we have used six year (2003-2009, with a total exposure of about 4 Ms) of publicly available data of the SPI telescope on-board of the INTEGRAL observatory, folded with the pulsar time solution derived from the Jodrell Bank Crab Pulsar Monthly Ephemeris. We found that the main pulse in the hard X-ray 20-100 keV energy band is leading the radio one by $8.18\pm0.46$ milliperiods in phase, or $275\pm15 \mu s$ in time. Quoted errors represent only statistical uncertainties.Our systematic error is estimated to be $\sim 40 \mu s$ and is mainly caused by the radio measurement uncertainties. In hard X-rays, the average distance between the main pulse and interpulse on the phase plane is $0.3989\pm0.0009$. To compare our findings in hard X-rays with the soft 2-20 keV X-ray band, we have used data of quasi-simultaneous Crab observations with the PCA monitor on-board the Rossi X-Ray Timing Explorer (RXTE) mission. The time lag and the pulses separation values measured in the 3-20 keV band are $0.00933\pm0.00016$ (corresponding to $310\pm6 \mu s$) and $0.40016\pm0.00028$ parts of the cycle, respectively. While the pulse separation values measured in soft X-rays and hard X-rays agree, the time lags are statistically different. Additional analysis show that the delay between the radio and X-ray signals varies with energy in the 2 - 300 keV energy range. We explain such a behaviour as due to the superposition of two independent components responsible for the Crab pulsed emission in this energy band.
