ERIC Educational Resources Information Center
Du, Yunfei
This paper discusses the impact of sampling error on the construction of confidence intervals around effect sizes. Sampling error affects the location and precision of confidence intervals. Meta-analytic resampling demonstrates that confidence intervals can haphazardly bounce around the true population parameter. Special software with graphical…
The Gas Sampling Interval Effect on V˙O2peak Is Independent of Exercise Protocol.
Scheadler, Cory M; Garver, Matthew J; Hanson, Nicholas J
2017-09-01
There is a plethora of gas sampling intervals available during cardiopulmonary exercise testing to measure peak oxygen consumption (V˙O2peak). Different intervals can lead to altered V˙O2peak. Whether differences are affected by the exercise protocol or subject sample is not clear. The purpose of this investigation was to determine whether V˙O2peak differed because of the manipulation of sampling intervals and whether differences were independent of the protocol and subject sample. The first subject sample (24 ± 3 yr; V˙O2peak via 15-breath moving averages: 56.2 ± 6.8 mL·kg·min) completed the Bruce and the self-paced V˙O2max protocols. The second subject sample (21.9 ± 2.7 yr; V˙O2peak via 15-breath moving averages: 54.2 ± 8.0 mL·kg·min) completed the Bruce and the modified Astrand protocols. V˙O2peak was identified using five sampling intervals: 15-s block averages, 30-s block averages, 15-breath block averages, 15-breath moving averages, and 30-s block averages aligned to the end of exercise. Differences in V˙O2peak between intervals were determined using repeated-measures ANOVAs. The influence of subject sample on the sampling effect was determined using independent t-tests. There was a significant main effect of sampling interval on V˙O2peak (first sample Bruce and self-paced V˙O2max P < 0.001; second sample Bruce and modified Astrand P < 0.05). The difference in V˙O2peak between sampling intervals followed a similar pattern for each protocol and subject sample, with 15-breath moving average presenting the highest V˙O2peak. The effect of manipulating gas sampling intervals on V˙O2peak appears to be protocol and sample independent. These findings highlight our recommendation that the clinical and scientific community request and report the sampling interval whenever metabolic data are presented. The standardization of reporting would assist in the comparison of V˙O2peak.
Sample Size Calculations for Precise Interval Estimation of the Eta-Squared Effect Size
ERIC Educational Resources Information Center
Shieh, Gwowen
2015-01-01
Analysis of variance is one of the most frequently used statistical analyses in the behavioral, educational, and social sciences, and special attention has been paid to the selection and use of an appropriate effect size measure of association in analysis of variance. This article presents the sample size procedures for precise interval estimation…
Sample Size Calculations for Precise Interval Estimation of the Eta-Squared Effect Size
ERIC Educational Resources Information Center
Shieh, Gwowen
2015-01-01
Analysis of variance is one of the most frequently used statistical analyses in the behavioral, educational, and social sciences, and special attention has been paid to the selection and use of an appropriate effect size measure of association in analysis of variance. This article presents the sample size procedures for precise interval estimation…
Effects of sampling interval on spatial patterns and statistics of watershed nitrogen concentration
Wu, S.-S.D.; Usery, E.L.; Finn, M.P.; Bosch, D.D.
2009-01-01
This study investigates how spatial patterns and statistics of a 30 m resolution, model-simulated, watershed nitrogen concentration surface change with sampling intervals from 30 m to 600 m for every 30 m increase for the Little River Watershed (Georgia, USA). The results indicate that the mean, standard deviation, and variogram sills do not have consistent trends with increasing sampling intervals, whereas the variogram ranges remain constant. A sampling interval smaller than or equal to 90 m is necessary to build a representative variogram. The interpolation accuracy, clustering level, and total hot spot areas show decreasing trends approximating a logarithmic function. The trends correspond to the nitrogen variogram and start to level at a sampling interval of 360 m, which is therefore regarded as a critical spatial scale of the Little River Watershed. Copyright ?? 2009 by Bellwether Publishing, Ltd. All right reserved.
Shieh, Gwowen
2013-03-01
Effect size reporting and interpreting practices have been extensively recommended in academic journals when primary outcomes of all empirical studies have been analyzed. This article presents an alternative approach to constructing confidence intervals of the weighted eta-squared effect size within the context of one-way heteroscedastic ANOVA models. It is shown that the proposed interval procedure has advantages over an existing method in its theoretical justification, computational simplicity, and numerical performance. For design planning, the corresponding sample size procedures for precise interval estimation of the weighted eta-squared association measure are also delineated. Specifically, the developed formulas compute the necessary sample sizes with respect to the considerations of expected confidence interval width and tolerance probability of interval width within a designated value. Supplementary computer programs are provided to aid the implementation of the suggested techniques in practical applications of ANOVA designs when the assumption of homogeneous variances is not tenable.
Lai, Keke; Kelley, Ken
2011-06-01
In addition to evaluating a structural equation model (SEM) as a whole, often the model parameters are of interest and confidence intervals for those parameters are formed. Given a model with a good overall fit, it is entirely possible for the targeted effects of interest to have very wide confidence intervals, thus giving little information about the magnitude of the population targeted effects. With the goal of obtaining sufficiently narrow confidence intervals for the model parameters of interest, sample size planning methods for SEM are developed from the accuracy in parameter estimation approach. One method plans for the sample size so that the expected confidence interval width is sufficiently narrow. An extended procedure ensures that the obtained confidence interval will be no wider than desired, with some specified degree of assurance. A Monte Carlo simulation study was conducted that verified the effectiveness of the procedures in realistic situations. The methods developed have been implemented in the MBESS package in R so that they can be easily applied by researchers.
Ouyang, Kesai; Lu, Siliang; Zhang, Shangbin; Zhang, Haibin; He, Qingbo; Kong, Fanrang
2015-08-27
The railway occupies a fairly important position in transportation due to its high speed and strong transportation capability. As a consequence, it is a key issue to guarantee continuous running and transportation safety of trains. Meanwhile, time consumption of the diagnosis procedure is of extreme importance for the detecting system. However, most of the current adopted techniques in the wayside acoustic defective bearing detector system (ADBD) are offline strategies, which means that the signal is analyzed after the sampling process. This would result in unavoidable time latency. Besides, the acquired acoustic signal would be corrupted by the Doppler effect because of high relative speed between the train and the data acquisition system (DAS). Thus, it is difficult to effectively diagnose the bearing defects immediately. In this paper, a new strategy called online Doppler effect elimination (ODEE) is proposed to remove the Doppler distortion online by the introduced unequal interval sampling scheme. The steps of proposed strategy are as follows: The essential parameters are acquired in advance. Then, the introduced unequal time interval sampling strategy is used to restore the Doppler distortion signal, and the amplitude of the signal is demodulated as well. Thus, the restored Doppler-free signal is obtained online. The proposed ODEE method has been employed in simulation analysis. Ultimately, the ODEE method is implemented in the embedded system for fault diagnosis of the train bearing. The results are in good accordance with the bearing defects, which verifies the good performance of the proposed strategy.
Ouyang, Kesai; Lu, Siliang; Zhang, Shangbin; Zhang, Haibin; He, Qingbo; Kong, Fanrang
2015-01-01
The railway occupies a fairly important position in transportation due to its high speed and strong transportation capability. As a consequence, it is a key issue to guarantee continuous running and transportation safety of trains. Meanwhile, time consumption of the diagnosis procedure is of extreme importance for the detecting system. However, most of the current adopted techniques in the wayside acoustic defective bearing detector system (ADBD) are offline strategies, which means that the signal is analyzed after the sampling process. This would result in unavoidable time latency. Besides, the acquired acoustic signal would be corrupted by the Doppler effect because of high relative speed between the train and the data acquisition system (DAS). Thus, it is difficult to effectively diagnose the bearing defects immediately. In this paper, a new strategy called online Doppler effect elimination (ODEE) is proposed to remove the Doppler distortion online by the introduced unequal interval sampling scheme. The steps of proposed strategy are as follows: The essential parameters are acquired in advance. Then, the introduced unequal time interval sampling strategy is used to restore the Doppler distortion signal, and the amplitude of the signal is demodulated as well. Thus, the restored Doppler-free signal is obtained online. The proposed ODEE method has been employed in simulation analysis. Ultimately, the ODEE method is implemented in the embedded system for fault diagnosis of the train bearing. The results are in good accordance with the bearing defects, which verifies the good performance of the proposed strategy. PMID:26343657
NASA Astrophysics Data System (ADS)
Krylov, S. N.; Smirnov, D. A.; Osipov, G. V.; Bezruchko, B. P.
2015-06-01
To analyze the coupling between oscillating systems by time series, the Granger causality assessment—an improved prognosis of the autoregression model—is widely used. It is known that wrong conclusions regarding the presence of bidirectional coupling can be obtained in the case of unidirectional coupled systems when the sampling interval is rather wide. However, it remains unclear under what conditions the effect of false coupling is significant, and thus criteria of significance to account for this effect in practice are absent. In this work, such conditions were studied and qualitatively formulated for an etalon system of coupled oscillators. In particular, it is shown that this effect is negligible in the case of insufficient data if a "fast" oscillator (with a smaller oscillation period and relaxation time) is driving a "slow" oscillator, while the effect is strong otherwise. If both periods are considerably larger than the sampling interval, the effect increases with relaxation time of the driving oscillator and decreases with increasing relaxation time of the driven one.
ERIC Educational Resources Information Center
Viechtbauer, Wolfgang
2007-01-01
Standardized effect sizes and confidence intervals thereof are extremely useful devices for comparing results across different studies using scales with incommensurable units. However, exact confidence intervals for standardized effect sizes can usually be obtained only via iterative estimation procedures. The present article summarizes several…
Tawfik, Ahmed M; Razek, Ahmed A; Elhawary, Galal; Batouty, Nihal M
2014-01-01
To evaluate the effect of increasing the sampling interval from 1 second (1 image per second) to 2 seconds (1 image every 2 seconds) on computed tomographic (CT) perfusion (CTP) of head and neck tumors. Twenty patients underwent CTP studies of head and neck tumors with images acquired in cine mode for 50 seconds using sampling interval of 1 second. Using deconvolution-based software, analysis of CTP was done with sampling interval of 1 second and then 2 seconds. Perfusion maps representing blood flow, blood volume, mean transit time, and permeability surface area product (PS) were obtained. Quantitative tumor CTP values were compared between the 2 sampling intervals. Two blinded radiologists compared the subjective quality of CTP maps using a 3-point scale between the 2 sampling intervals. Radiation dose parameters were recorded for the 2 sampling interval rates. No significant differences were observed between the means of the 4 perfusion parameters generated using both sampling intervals; all P >0.05. The 95% limits of agreement between the 2 sampling intervals were -65.9 to 48.1) mL/min per 100 g for blood flow, -3.6 to 3.1 mL/100 g for blood volume, -2.9 to 3.8 seconds for mean transit time, and -10.0 to 12.5 mL/min per 100 g for PS. There was no significant difference between the subjective quality scores of CTP maps obtained using the 2 sampling intervals; all P > 0.05. Radiation dose was halved when sampling interval increased from 1 to 2 seconds. Increasing the sampling interval rate to 1 image every 2 seconds does not compromise the image quality and has no significant effect on quantitative perfusion parameters of head and neck tumors. The radiation dose is halved.
ERIC Educational Resources Information Center
Lai, Keke; Kelley, Ken
2011-01-01
In addition to evaluating a structural equation model (SEM) as a whole, often the model parameters are of interest and confidence intervals for those parameters are formed. Given a model with a good overall fit, it is entirely possible for the targeted effects of interest to have very wide confidence intervals, thus giving little information about…
ERIC Educational Resources Information Center
Radley, Keith C.; O'Handley, Roderick D.; Labrot, Zachary C.
2015-01-01
Assessment in social skills training often utilizes procedures such as partial-interval recording (PIR) and momentary time sampling (MTS) to estimate changes in duration in social engagements due to intervention. Although previous research suggests PIR to be more inaccurate than MTS in estimating levels of behavior, treatment analysis decisions…
ERIC Educational Resources Information Center
Radley, Keith C.; O'Handley, Roderick D.; Labrot, Zachary C.
2015-01-01
Assessment in social skills training often utilizes procedures such as partial-interval recording (PIR) and momentary time sampling (MTS) to estimate changes in duration in social engagements due to intervention. Although previous research suggests PIR to be more inaccurate than MTS in estimating levels of behavior, treatment analysis decisions…
Representing spike trains using constant sampling intervals.
Hirata, Yoshito; Aihara, Kazuyuki
2009-10-15
Sensory neurons encode external information by a series of times of action potentials, which is called a spike train. However, since it is a point process, it is hard to analyze. Here we propose a method for converting a spike train into a real-valued time series with a fixed sampling interval under the assumption of temporal codes. The proposed method yields time series that represent encoded signals. Especially when the method is applied to spike trains generated using integrate-and-fire models, the yielded time series look very similar to those of encoded information. The method works robustly even when a spike train is contaminated with noise. Since unlike filters it does not use its original signals for the conversion, the proposed method can be widely used for investigating spike train data in the real world.
Effect Sizes, Confidence Intervals, and Confidence Intervals for Effect Sizes
ERIC Educational Resources Information Center
Thompson, Bruce
2007-01-01
The present article provides a primer on (a) effect sizes, (b) confidence intervals, and (c) confidence intervals for effect sizes. Additionally, various admonitions for reformed statistical practice are presented. For example, a very important implication of the realization that there are dozens of effect size statistics is that "authors must…
Improved interval estimation of comparative treatment effects
NASA Astrophysics Data System (ADS)
Van Krevelen, Ryne Christian
Comparative experiments, in which subjects are randomized to one of two treatments, are performed often. There is no shortage of papers testing whether a treatment effect exists and providing confidence intervals for the magnitude of this effect. While it is well understood that the object and scope of inference for an experiment will depend on what assumptions are made, these entities are not always clearly presented. We have proposed one possible method, which is based on the ideas of Jerzy Neyman, that can be used for constructing confidence intervals in a comparative experiment. The resulting intervals, referred to as Neyman-type confidence intervals, can be applied in a wide range of cases. Special care is taken to note which assumptions are made and what object and scope of inference are being investigated. We have presented a notation that highlights which parts of a problem are being treated as random. This helps ensure the focus on the appropriate scope of inference. The Neyman-type confidence intervals are compared to possible alternatives in two different inference settings: one in which inference is made about the units in the sample and one in which inference is made about units in a fixed population. A third inference setting, one in which inference is made about a process distribution, is also discussed. It is stressed that certain assumptions underlying this third type of inference are unverifiable. When these assumptions are not met, the resulting confidence intervals may cover their intended target well below the desired rate. Through simulation, we demonstrate that the Neyman-type intervals have good coverage properties when inference is being made about a sample or a population. In some cases the alternative intervals are much wider than necessary on average. Therefore, we recommend that researchers consider using our Neyman-type confidence intervals when carrying out inference about a sample or a population as it may provide them with more
INTERVAL SAMPLING METHODS AND MEASUREMENT ERROR: A COMPUTER SIMULATION
Wirth, Oliver; Slaven, James; Taylor, Matthew A.
2015-01-01
A simulation study was conducted to provide a more thorough account of measurement error associated with interval sampling methods. A computer program simulated the application of momentary time sampling, partial-interval recording, and whole-interval recording methods on target events randomly distributed across an observation period. The simulation yielded measures of error for multiple combinations of observation period, interval duration, event duration, and cumulative event duration. The simulations were conducted up to 100 times to yield measures of error variability. Although the present simulation confirmed some previously reported characteristics of interval sampling methods, it also revealed many new findings that pertain to each method’s inherent strengths and weaknesses. The analysis and resulting error tables can help guide the selection of the most appropriate sampling method for observation-based behavioral assessments. PMID:24127380
Interval sampling methods and measurement error: a computer simulation.
Wirth, Oliver; Slaven, James; Taylor, Matthew A
2014-01-01
A simulation study was conducted to provide a more thorough account of measurement error associated with interval sampling methods. A computer program simulated the application of momentary time sampling, partial-interval recording, and whole-interval recording methods on target events randomly distributed across an observation period. The simulation yielded measures of error for multiple combinations of observation period, interval duration, event duration, and cumulative event duration. The simulations were conducted up to 100 times to yield measures of error variability. Although the present simulation confirmed some previously reported characteristics of interval sampling methods, it also revealed many new findings that pertain to each method's inherent strengths and weaknesses. The analysis and resulting error tables can help guide the selection of the most appropriate sampling method for observation-based behavioral assessments. © Society for the Experimental Analysis of Behavior.
Sampling Theorem in Terms of the Bandwidth and Sampling Interval
NASA Technical Reports Server (NTRS)
Dean, Bruce H.
2011-01-01
An approach has been developed for interpolating non-uniformly sampled data, with applications in signal and image reconstruction. This innovation generalizes the Whittaker-Shannon sampling theorem by emphasizing two assumptions explicitly (definition of a band-limited function and construction by periodic extension). The Whittaker- Shannon sampling theorem is thus expressed in terms of two fundamental length scales that are derived from these assumptions. The result is more general than what is usually reported, and contains the Whittaker- Shannon form as a special case corresponding to Nyquist-sampled data. The approach also shows that the preferred basis set for interpolation is found by varying the frequency component of the basis functions in an optimal way.
Comparing interval estimates for small sample ordinal CFA models.
Natesan, Prathiba
2015-01-01
Robust maximum likelihood (RML) and asymptotically generalized least squares (AGLS) methods have been recommended for fitting ordinal structural equation models. Studies show that some of these methods underestimate standard errors. However, these studies have not investigated the coverage and bias of interval estimates. An estimate with a reasonable standard error could still be severely biased. This can only be known by systematically investigating the interval estimates. The present study compares Bayesian, RML, and AGLS interval estimates of factor correlations in ordinal confirmatory factor analysis models (CFA) for small sample data. Six sample sizes, 3 factor correlations, and 2 factor score distributions (multivariate normal and multivariate mildly skewed) were studied. Two Bayesian prior specifications, informative and relatively less informative were studied. Undercoverage of confidence intervals and underestimation of standard errors was common in non-Bayesian methods. Underestimated standard errors may lead to inflated Type-I error rates. Non-Bayesian intervals were more positive biased than negatively biased, that is, most intervals that did not contain the true value were greater than the true value. Some non-Bayesian methods had non-converging and inadmissible solutions for small samples and non-normal data. Bayesian empirical standard error estimates for informative and relatively less informative priors were closer to the average standard errors of the estimates. The coverage of Bayesian credibility intervals was closer to what was expected with overcoverage in a few cases. Although some Bayesian credibility intervals were wider, they reflected the nature of statistical uncertainty that comes with the data (e.g., small sample). Bayesian point estimates were also more accurate than non-Bayesian estimates. The results illustrate the importance of analyzing coverage and bias of interval estimates, and how ignoring interval estimates can be misleading
Comparing interval estimates for small sample ordinal CFA models
Natesan, Prathiba
2015-01-01
Robust maximum likelihood (RML) and asymptotically generalized least squares (AGLS) methods have been recommended for fitting ordinal structural equation models. Studies show that some of these methods underestimate standard errors. However, these studies have not investigated the coverage and bias of interval estimates. An estimate with a reasonable standard error could still be severely biased. This can only be known by systematically investigating the interval estimates. The present study compares Bayesian, RML, and AGLS interval estimates of factor correlations in ordinal confirmatory factor analysis models (CFA) for small sample data. Six sample sizes, 3 factor correlations, and 2 factor score distributions (multivariate normal and multivariate mildly skewed) were studied. Two Bayesian prior specifications, informative and relatively less informative were studied. Undercoverage of confidence intervals and underestimation of standard errors was common in non-Bayesian methods. Underestimated standard errors may lead to inflated Type-I error rates. Non-Bayesian intervals were more positive biased than negatively biased, that is, most intervals that did not contain the true value were greater than the true value. Some non-Bayesian methods had non-converging and inadmissible solutions for small samples and non-normal data. Bayesian empirical standard error estimates for informative and relatively less informative priors were closer to the average standard errors of the estimates. The coverage of Bayesian credibility intervals was closer to what was expected with overcoverage in a few cases. Although some Bayesian credibility intervals were wider, they reflected the nature of statistical uncertainty that comes with the data (e.g., small sample). Bayesian point estimates were also more accurate than non-Bayesian estimates. The results illustrate the importance of analyzing coverage and bias of interval estimates, and how ignoring interval estimates can be misleading
Small Sample Theory for Steady State Confidence Intervals
1989-06-01
confidence interval for the mean of a stationary sequence. As indicated in the literature, nonparametric confidence intervals in practice often have undesirable small-sample asymmetry and coverage characteristics. These phenomena are partially due to the fact that the third and fourth cumulants of the point estimator for the stationary mean, unlike those of the standard normal random variable, are not zero. We will apply Edgeworth and Cornish-Fisher expansions to obtain asymptotic expansions for the errors associated with confidence intervals. The analysis isolates various
Relativistic rise measurements with very fine sampling intervals
Ludlam, T.; Platner, E.D.; Polychronakos, V.A.; Lindenbaum, S.J.; Kramer, M.A.; Teramoto, Y.
1980-01-01
The motivation of this work was to determine whether the technique of charged particle identification via the relativistic rise in the ionization loss can be significantly improved by virtue of very small sampling intervals. A fast-sampling ADC and a longitudinal drift geometry were used to provide a large number of samples from a single drift chamber gap, achieving sampling intervals roughly 10 times smaller than any previous study. A single layer drift chamber was used, and tracks of 1 meter length were simulated by combining together samples from many identified particles in this detector. These data were used to study the resolving power for particle identification as a function of sample size, averaging technique, and the number of discrimination levels (ADC bits) used for pulse height measurements.
Estimation of the sampling interval error for LED measurement with a goniophotometer
NASA Astrophysics Data System (ADS)
Zhao, Weiqiang; Liu, Hui; Liu, Jian
2013-06-01
Using a goniophotometer to implant a total luminous flux measurement, an error comes from the sampling interval, especially in the situation for LED measurement. In this work, we use computer calculations to estimate the effect of sampling interval on the measuring the total luminous flux for four typical kinds of LEDs, whose spatial distributions of luminous intensity is similar to those LEDs shown in CIE 127 paper. Four basic kinds of mathematical functions are selected to simulate the distribution curves. Axial symmetric type LED and non-axial symmetric type LED are both take amount of. We consider polar angle sampling interval of 0.5°, 1°, 2°, and 5° respectively in one rotation for axial symmetric type, and consider azimuth angle sampling interval of 18°, 15°, 12°, 10° and 5° respectively for non-axial symmetric type. We noted that the error is strongly related to spatial distribution. However, for common LED light sources the calculation results show that a usage of polar angle sampling interval of 2° and azimuth angle sampling interval of 15° is recommended. The systematic error of sampling interval for a goniophotometer can be controlled at the level of 0.3%. For high precise level, the usage of polar angle sampling interval of 1° and azimuth angle sampling interval of 10° should be used.
ROMERO,VICENTE J.
2000-05-04
In order to devise an algorithm for autonomously terminating Monte Carlo sampling when sufficiently small and reliable confidence intervals (CI) are achieved on calculated probabilities, the behavior of CI estimators must be characterized. This knowledge is also required in comparing the accuracy of other probability estimation techniques to Monte Carlo results. Based on 100 trials in a hypothesis test, estimated 95% CI from classical approximate CI theory are empirically examined to determine if they behave as true 95% CI over spectrums of probabilities (population proportions) ranging from 0.001 to 0.99 in a test problem. Tests are conducted for population sizes of 500 and 10,000 samples where applicable. Significant differences between true and estimated 95% CI are found to occur at probabilities between 0.1 and 0.9, such that estimated 95% CI can be rejected as not being true 95% CI at less than a 40% chance of incorrect rejection. With regard to Latin Hypercube sampling (LHS), though no general theory has been verified for accurately estimating LHS CI, recent numerical experiments on the test problem have found LHS to be conservatively over an order of magnitude more efficient than SRS for similar sized CI on probabilities ranging between 0.25 and 0.75. The efficiency advantage of LHS vanishes, however, as the probability extremes of 0 and 1 are approached.
Number of core samples: Mean concentrations and confidence intervals
Jensen, L.; Cromar, R.D.; Wilmarth, S.R.; Heasler, P.G.
1995-01-24
This document provides estimates of how well the mean concentration of analytes are known as a function of the number of core samples, composite samples, and replicate analyses. The estimates are based upon core composite data from nine recently sampled single-shell tanks. The results can be used when determining the number of core samples needed to ``characterize`` the waste from similar single-shell tanks. A standard way of expressing uncertainty in the estimate of a mean is with a 95% confidence interval (CI). The authors investigate how the width of a 95% CI on the mean concentration decreases as the number of observations increase. Specifically, the tables and figures show how the relative half-width (RHW) of a 95% CI decreases as the number of core samples increases. The RHW of a CI is a unit-less measure of uncertainty. The general conclusions are as follows: (1) the RHW decreases dramatically as the number of core samples is increased, the decrease is much smaller when the number of composited samples or the number of replicate analyses are increase; (2) if the mean concentration of an analyte needs to be estimated with a small RHW, then a large number of core samples is required. The estimated number of core samples given in the tables and figures were determined by specifying different sizes of the RHW. Four nominal sizes were examined: 10%, 25%, 50%, and 100% of the observed mean concentration. For a majority of analytes the number of core samples required to achieve an accuracy within 10% of the mean concentration is extremely large. In many cases, however, two or three core samples is sufficient to achieve a RHW of approximately 50 to 100%. Because many of the analytes in the data have small concentrations, this level of accuracy may be satisfactory for some applications.
A Robust Confidence Interval for Samples of Five Observations.
1979-11-01
A robust confidence interval using biweights for the case of five observations is proposed when the underlying distribution has somewhat heavier...probabilities, the intervals proposed are highly efficient, in terms of the expected length of the confidence interval . (Author)
Borges, I C; Andrade, D C; Vilas-Boas, A-L; Fontoura, M-S H; Laitinen, H; Ekström, N; Adrian, P V; Meinke, A; Cardoso, M-R A; Barral, A; Ruuskanen, O; Käyhty, H; Nascimento-Carvalho, C M
2015-08-01
We evaluated the effects of combining different numbers of pneumococcal antigens, pre-existing antibody levels, sampling interval, age, and duration of illness on the detection of IgG responses against eight Streptococcus pneumoniae proteins, three Haemophilus influenzae proteins, and five Moraxella catarrhalis proteins in 690 children aged <5 years with pneumonia. Serological tests were performed on acute and convalescent serum samples with a multiplexed bead-based immunoassay. The median sampling interval was 19 days, the median age was 26.7 months, and the median duration of illness was 5 days. The rate of antibody responses was 15.4 % for at least one pneumococcal antigen, 5.8 % for H. influenzae, and 2.3 % for M. catarrhalis. The rate of antibody responses against each pneumococcal antigen varied from 3.5 to 7.1 %. By multivariate analysis, pre-existing antibody levels showed a negative association with the detection of antibody responses against pneumococcal and H. influenzae antigens; the sampling interval was positively associated with the detection of antibody responses against pneumococcal and H. influenzae antigens. A sampling interval of 3 weeks was the optimal cut-off for the detection of antibody responses against pneumococcal and H. influenzae proteins. Duration of illness was negatively associated with antibody responses against PspA. Age did not influence antibody responses against the investigated antigens. In conclusion, serological assays using combinations of different pneumococcal proteins detect a higher rate of antibody responses against S. pneumoniae compared to assays using a single pneumococcal protein. Pre-existing antibody levels and sampling interval influence the detection of antibody responses against pneumococcal and H. influenzae proteins. These factors should be considered when determining pneumonia etiology by serological methods in children.
Sample Size for the "Z" Test and Its Confidence Interval
ERIC Educational Resources Information Center
Liu, Xiaofeng Steven
2012-01-01
The statistical power of a significance test is closely related to the length of the confidence interval (i.e. estimate precision). In the case of a "Z" test, the length of the confidence interval can be expressed as a function of the statistical power. (Contains 1 figure and 1 table.)
Sample Size for the "Z" Test and Its Confidence Interval
ERIC Educational Resources Information Center
Liu, Xiaofeng Steven
2012-01-01
The statistical power of a significance test is closely related to the length of the confidence interval (i.e. estimate precision). In the case of a "Z" test, the length of the confidence interval can be expressed as a function of the statistical power. (Contains 1 figure and 1 table.)
Terry, Leann; Kelley, Ken
2012-11-01
Composite measures play an important role in psychology and related disciplines. Composite measures almost always have error. Correspondingly, it is important to understand the reliability of the scores from any particular composite measure. However, the point estimates of the reliability of composite measures are fallible and thus all such point estimates should be accompanied by a confidence interval. When confidence intervals are wide, there is much uncertainty in the population value of the reliability coefficient. Given the importance of reporting confidence intervals for estimates of reliability, coupled with the undesirability of wide confidence intervals, we develop methods that allow researchers to plan sample size in order to obtain narrow confidence intervals for population reliability coefficients. We first discuss composite reliability coefficients and then provide a discussion on confidence interval formation for the corresponding population value. Using the accuracy in parameter estimation approach, we develop two methods to obtain accurate estimates of reliability by planning sample size. The first method provides a way to plan sample size so that the expected confidence interval width for the population reliability coefficient is sufficiently narrow. The second method ensures that the confidence interval width will be sufficiently narrow with some desired degree of assurance (e.g., 99% assurance that the 95% confidence interval for the population reliability coefficient will be less than W units wide). The effectiveness of our methods was verified with Monte Carlo simulation studies. We demonstrate how to easily implement the methods with easy-to-use and freely available software. ©2011 The British Psychological Society.
Cost effective mass standard calibration intervals
Shull, A.H.; Clark, J.P.
1995-11-01
National Institute of Standards and Technology (NIST) traceable standard weights serve as the foundation of mass measurement control programs. These standards are normally recalibrated annually at a cost of approximately $100 per weight. The Savannah River Site (SRS) has more than 4,000 standard weights. Most have recalibration intervals of 1 year. The cost effectiveness of the current practice was questioned. Are these mass standards being calibrated too often, and are all of these standards needed for calibration and QC activities? Statistical analyses of data from the calibration histories were performed on a random sample of eight weight sets. The analyses indicated no time effects or significant trends in the weight masses for periods of from 5 to 8 years. In other words, calibration checks were being performed too frequently. In addition, current electronic balance technology does not require a traditional set of standard weights that cover the entire weighing range of a balance. At the most, only 2 or 3 standards are needed for most weighing systems. Hence, by increasing weight set recalibration frequencies from 1 to 3 years, and by reducing the number standards calibrated by 80%, annual cost savings of over $400,000 are attainable at SRS. Details of the data analysis, technological advances, and cost savings are included in the paper.
ERIC Educational Resources Information Center
Algina, James; Moulder, Bradley C.
2001-01-01
Studied sample sizes for confidence intervals on the increase in the squared multiple correlation coefficient using simulation. Discusses predictors and actual coverage probability and provides sample-size guidelines for probability coverage to be near the nominal confidence interval. (SLD)
ON-LINE TOOLS FOR PROPER VERTICAL POSITIONING OF VERTICAL SAMPLING INTERVALS DURING SITE ASSESSMENT
This presentation presents on-line tools for proper vertical positioning of vertical sampling intervals during site assessment. Proper vertical sample interval selection is critical for generate data on the vertical distribution of contamination. Without vertical delineation, th...
ERIC Educational Resources Information Center
Algina, James; Moulder, Bradley C.
2001-01-01
Studied sample sizes for confidence intervals on the increase in the squared multiple correlation coefficient using simulation. Discusses predictors and actual coverage probability and provides sample-size guidelines for probability coverage to be near the nominal confidence interval. (SLD)
Hanley, J A; Hagen, C A; Shiferaw, T
1996-01-01
The sisterhood method is an indirect method of estimating maternal mortality that has, in comparison with conventional direct methods, the dual advantages of ease of use in the field and smaller sample-size requirements. This report describes how to calculate a standard error to quantify the sampling variability for this method. This standard error can be used to construct confidence intervals and statistical tests and to plan the size of a sample survey that employs the sisterhood method. Statistical assumptions are discussed, particularly in relation to the effective sample size and to effects of extrabinomial variation. In a worked example of data from urban Pakistan, a maternal mortality ratio of 153 (95 percent confidence interval between 96 and 212) deaths per 100,000 live births is estimated.
Nonparametric confidence intervals for the one- and two-sample problems.
Zhou, Xiao Hua; Dinh, Phillip
2005-04-01
Confidence intervals for the mean of one sample and the difference in means of two independent samples based on the ordinary-t statistic suffer deficiencies when samples come from skewed families. In this article we evaluate several existing techniques and propose new methods to improve coverage accuracy. The methods examined include the ordinary-t, the bootstrap-t, the biased-corrected acceleration and three new intervals based on transformation of the t-statistic. Our study shows that our new transformation intervals and the bootstrap-t intervals give best coverage accuracy for a variety of skewed distributions, and that our new transformation intervals have shorter interval lengths.
ERIC Educational Resources Information Center
Hess, Melinda R.; Hogarty, Kristine Y.; Ferron, John M.; Kromrey, Jeffrey D.
2007-01-01
Monte Carlo methods were used to examine techniques for constructing confidence intervals around multivariate effect sizes. Using interval inversion and bootstrapping methods, confidence intervals were constructed around the standard estimate of Mahalanobis distance (D[superscript 2]), two bias-adjusted estimates of D[superscript 2], and Huberty's…
Exact intervals and tests for median when one sample value possibly an outliner
NASA Technical Reports Server (NTRS)
Keller, G. J.; Walsh, J. E.
1973-01-01
Available are independent observations (continuous data) that are believed to be a random sample. Desired are distribution-free confidence intervals and significance tests for the population median. However, there is the possibility that either the smallest or the largest observation is an outlier. Then, use of a procedure for rejection of an outlying observation might seem appropriate. Such a procedure would consider that two alternative situations are possible and would select one of them. Either (1) the n observations are truly a random sample, or (2) an outlier exists and its removal leaves a random sample of size n-1. For either situation, confidence intervals and tests are desired for the median of the population yielding the random sample. Unfortunately, satisfactory rejection procedures of a distribution-free nature do not seem to be available. Moreover, all rejection procedures impose undesirable conditional effects on the observations, and also, can select the wrong one of the two above situations. It is found that two-sided intervals and tests based on two symmetrically located order statistics (not the largest and smallest) of the n observations have this property.
Introduction to Sample Size Choice for Confidence Intervals Based on "t" Statistics
ERIC Educational Resources Information Center
Liu, Xiaofeng Steven; Loudermilk, Brandon; Simpson, Thomas
2014-01-01
Sample size can be chosen to achieve a specified width in a confidence interval. The probability of obtaining a narrow width given that the confidence interval includes the population parameter is defined as the power of the confidence interval, a concept unfamiliar to many practitioners. This article shows how to utilize the Statistical Analysis…
Introduction to Sample Size Choice for Confidence Intervals Based on "t" Statistics
ERIC Educational Resources Information Center
Liu, Xiaofeng Steven; Loudermilk, Brandon; Simpson, Thomas
2014-01-01
Sample size can be chosen to achieve a specified width in a confidence interval. The probability of obtaining a narrow width given that the confidence interval includes the population parameter is defined as the power of the confidence interval, a concept unfamiliar to many practitioners. This article shows how to utilize the Statistical Analysis…
Relativistic rise measurements with very fine sampling intervals: prospects for Isabelle
Ludlam, T.; Platner, E.D.
1981-01-01
In a recent (and ongoing) series of tests it has been shown that the sensitivity for charged particle identification via the relativistic rise in ionization loss can be significantly enhanced by using longitudinal drift and fast electronics to effect very small sampling intervals. With the chamber geometry illustrated, electrons from individual ionizing collisions drift sequentially onto the anode wire with a time structure determined by the drift velocity in the gas. After fast pulse shaping (the signal is shaped by a tail-cancelling pole-zero filter with 40 nanosecond shaping time), the resultant waveform is digitized with a fast-sampling ADC at a frequency of 100 MHz.
The impact of different sampling rates and calculation time intervals on ROTI values
NASA Astrophysics Data System (ADS)
Jacobsen, Knut Stanley
2014-11-01
The ROTI (Rate of TEC index) is a commonly used measure of ionospheric irregularities level. The algorithm to calculate ROTI is easily implemented, and is the same from paper to paper. However, the sample rate of the GNSS data used, and the time interval over which a value of ROTI is calculated, varies from paper to paper. When comparing ROTI values from different studies, this must be taken into account. This paper aims to show what these differences are, to increase the awareness of this issue. We have investigated the effect of different parameters for the calculation of ROTI values, using one year of data from 8 receivers at latitudes ranging from 59° N to 79° N. We have found that the ROTI values calculated using different parameter choices are strongly positively correlated. However, the ROTI values are quite different. The effect of a lower sample rate is to lower the ROTI value, due to the loss of high-frequency parts of the ROT spectrum, while the effect of a longer calculation time interval is to remove or reduce short-lived peaks due to the inherent smoothing effect. The ratio of ROTI values based on data of different sampling rate is examined in relation to the ROT power spectrum. Of relevance to statistical studies, we find that the median level of ROTI depends strongly on sample rate, strongly on latitude at auroral latitudes, and weakly on time interval. Thus, a baseline "quiet" or "noisy" level for one location or choice or parameters may not be valid for another location or choice of parameters.
Effects of Peginesatide Injection on QTc Interval in Healthy Adults
Czerniak, Richard; Kukulka, Michael; Wu, Jing Tao; Qiu, Ping
2014-01-01
A single-dose, randomized, double-blind, placebo- and positive-controlled, three-period crossover study was conducted to evaluate the effect of peginesatide injection on QT interval in healthy adults. Subjects received single doses of placebo, peginesatide injection 0.1 mg/kg intravenous, or moxifloxacin 400 mg during three treatment periods, separated by 14-day washout intervals. ECG recordings and blood samples for peginesatide and moxifloxacin plasma concentrations were collected prior to dosing and through 22 hours postdose. QT intervals were measured with a high resolution manual on-screen caliper method. The study endpoint was the mean difference between peginesatide and placebo in baseline-adjusted corrected QT interval (ddQTc). The maximum upper bound of the one-sided 95% CI was 2.2 milliseconds at 0.75 hours for Fridericia-corrected ddQTc (ddQTcF) and 2.2 milliseconds at 0.25 hours for individual corrected ddQTcI. The linear relationship between ddQTcF and peginesatide concentrations was essentially flat and not statistically significant [slope = 0.001, P = 0.126, 90% CI: (<−0.0005, 0.002)]. Using this model, the projected ddQTcF effect at the observed mean peak plasma concentration is estimated to be 0.9 milliseconds, 90% CI: (−2.0, 0.3 milliseconds). There were no peginesatide-related effects on heart rate, PR interval, or QRS interval. Thus, there is no anticipated cardiovascular effect of peginesatide injection 0.1 mg/kg in patients. PMID:26161294
Effects of Peginesatide Injection on QTc Interval in Healthy Adults.
Czerniak, Richard; Kukulka, Michael; Wu, Jing Tao; Qiu, Ping
2014-11-01
A single-dose, randomized, double-blind, placebo- and positive-controlled, three-period crossover study was conducted to evaluate the effect of peginesatide injection on QT interval in healthy adults. Subjects received single doses of placebo, peginesatide injection 0.1 mg/kg intravenous, or moxifloxacin 400 mg during three treatment periods, separated by 14-day washout intervals. ECG recordings and blood samples for peginesatide and moxifloxacin plasma concentrations were collected prior to dosing and through 22 hours postdose. QT intervals were measured with a high resolution manual on-screen caliper method. The study endpoint was the mean difference between peginesatide and placebo in baseline-adjusted corrected QT interval (ddQTc). The maximum upper bound of the one-sided 95% CI was 2.2 milliseconds at 0.75 hours for Fridericia-corrected ddQTc (ddQTcF) and 2.2 milliseconds at 0.25 hours for individual corrected ddQTcI. The linear relationship between ddQTcF and peginesatide concentrations was essentially flat and not statistically significant [slope = 0.001, P = 0.126, 90% CI: (<-0.0005, 0.002)]. Using this model, the projected ddQTcF effect at the observed mean peak plasma concentration is estimated to be 0.9 milliseconds, 90% CI: (-2.0, 0.3 milliseconds). There were no peginesatide-related effects on heart rate, PR interval, or QRS interval. Thus, there is no anticipated cardiovascular effect of peginesatide injection 0.1 mg/kg in patients.
Mukumoto, Nobutaka; Nakamura, Mitsuhiro; Akimoto, Mami; Miyabe, Yuki; Yokota, Kenji; Matsuo, Yukinori; Mizowaki, Takashi; Hiraoka, Masahiro
2017-08-01
To explore the effect of sampling interval of training data acquisition on the intrafractional prediction error of surrogate signal-based dynamic tumor-tracking using a gimbal-mounted linac. Twenty pairs of respiratory motions were acquired from 20 patients (ten lung, five liver, and five pancreatic cancer patients) who underwent dynamic tumor-tracking with the Vero4DRT. First, respiratory motions were acquired as training data for an initial construction of the prediction model before the irradiation. Next, additional respiratory motions were acquired for an update of the prediction model due to the change of the respiratory pattern during the irradiation. The time elapsed prior to the second acquisition of the respiratory motion was 12.6 ± 3.1 min. A four-axis moving phantom reproduced patients' three dimensional (3D) target motions and one dimensional surrogate motions. To predict the future internal target motion from the external surrogate motion, prediction models were constructed by minimizing residual prediction errors for training data acquired at 80 and 320 ms sampling intervals for 20 s, and at 500, 1,000, and 2,000 ms sampling intervals for 60 s using orthogonal kV x-ray imaging systems. The accuracies of prediction models trained with various sampling intervals were estimated based on training data with each sampling interval during the training process. The intrafractional prediction errors for various prediction models were then calculated on intrafractional monitoring images taken for 30 s at the constant sampling interval of a 500 ms fairly to evaluate the prediction accuracy for the same motion pattern. In addition, the first respiratory motion was used for the training and the second respiratory motion was used for the evaluation of the intrafractional prediction errors for the changed respiratory motion to evaluate the robustness of the prediction models. The training error of the prediction model was 1.7 ± 0.7 mm in 3D for all sampling
Sample size determination for the confidence interval of linear contrast in analysis of covariance.
Liu, Xiaofeng Steven
2013-03-11
This article provides a way to determine sample size for the confidence interval of the linear contrast of treatment means in analysis of covariance (ANCOVA) without prior knowledge of the actual covariate means and covariate sum of squares, which are modeled as a t statistic. Using the t statistic, one can calculate the appropriate sample size to achieve the desired probability of obtaining a specified width in the confidence interval of the covariate-adjusted linear contrast.
Interval data and sample variance: Expected computational complexity of upper bound
NASA Astrophysics Data System (ADS)
Sokol, Ondřej; Rada, Miroslav; Černý, Michal
2017-07-01
Computation of the tight upper bound on the sample variance of an interval-valued dataset is known to be NP-hard. However, using Ferson's algorithm, the computation of the maximal possible variance over interval-valued dataset can be realized in polynomial time in the maximal number of narrowed intervals intersecting at one point; narrowed means that the intervals are shrinked proportionally to the size of the dataset. Simulation experiments allowed to conjecturing that the maximal number of narrowed intervals intersecting at one point is at most of logarithmic size for a reasonable choice of the data-generating process. Here, we assume uniform distribution of centers and constant radii. Under this setting, we sketch an approach how to prove the polynomiality of computation of upper bound of sample variance over random data.
ERIC Educational Resources Information Center
Kelley, Ken
2005-01-01
The standardized group mean difference, Cohen's "d", is among the most commonly used and intuitively appealing effect sizes for group comparisons. However, reporting this point estimate alone does not reflect the extent to which sampling error may have led to an obtained value. A confidence interval expresses the uncertainty that exists between…
NASA Astrophysics Data System (ADS)
Yang, Feisheng; Zhang, Huaguang; Liu, Zhenwei; Li, Ranran
2014-03-01
This work is concerned with the robust resilient control problem for uncertain networked control systems (NCSs) with variable sampling intervals, variant-induced delays and possible data dropouts, which is seldom considered in current literature. It is mainly based on the continuous time-varying-delay system approach. Followed by the nominal case, delay-dependent resilient robust stabilising conditions for the closed-loop NCS against controller gain variations are derived by employing a novel Lyapunov-Krasovskii functional which makes good use of the information of both lower and upper bounds on the varying input delay, and the upper bound on the variable sampling interval as well. A feasible solution of the obtained criterion formulated as linear matrix inequalities can be gotten. A tighter bounding technique is presented for acquiring the time derivative of the functional so as to utilise many more useful elements, meanwhile neither slack variable nor correlated augmented item is introduced to reduce overall computational burden. Two examples are given to show the effectiveness of the proposed method.
Notes on interval estimation of the gamma correlation under stratified random sampling.
Lui, Kung-Jong; Chang, Kuang-Chao
2012-07-01
We have developed four asymptotic interval estimators in closed forms for the gamma correlation under stratified random sampling, including the confidence interval based on the most commonly used weighted-least-squares (WLS) approach (CIWLS), the confidence interval calculated from the Mantel-Haenszel (MH) type estimator with the Fisher-type transformation (CIMHT), the confidence interval using the fundamental idea of Fieller's Theorem (CIFT) and the confidence interval derived from a monotonic function of the WLS estimator of Agresti's α with the logarithmic transformation (MWLSLR). To evaluate the finite-sample performance of these four interval estimators and note the possible loss of accuracy in application of both Wald's confidence interval and MWLSLR using pooled data without accounting for stratification, we employ Monte Carlo simulation. We use the data taken from a general social survey studying the association between the income level and job satisfaction with strata formed by genders in black Americans published elsewhere to illustrate the practical use of these interval estimators. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Notes on interval estimation of the generalized odds ratio under stratified random sampling.
Lui, Kung-Jong; Chang, Kuang-Chao
2013-05-01
It is not rare to encounter the patient response on the ordinal scale in a randomized clinical trial (RCT). Under the assumption that the generalized odds ratio (GOR) is homogeneous across strata, we consider four asymptotic interval estimators for the GOR under stratified random sampling. These include the interval estimator using the weighted-least-squares (WLS) approach with the logarithmic transformation (WLSL), the interval estimator using the Mantel-Haenszel (MH) type of estimator with the logarithmic transformation (MHL), the interval estimator using Fieller's theorem with the MH weights (FTMH) and the interval estimator using Fieller's theorem with the WLS weights (FTWLS). We employ Monte Carlo simulation to evaluate the performance of these interval estimators by calculating the coverage probability and the average length. To study the bias of these interval estimators, we also calculate and compare the noncoverage probabilities in the two tails of the resulting confidence intervals. We find that WLSL and MHL can generally perform well, while FTMH and FTWLS can lose either precision or accuracy. We further find that MHL is likely the least biased. Finally, we use the data taken from a study of smoking status and breathing test among workers in certain industrial plants in Houston, Texas, during 1974 to 1975 to illustrate the use of these interval estimators.
Multiport well design for sampling of ground water at closely spaced vertical intervals
Delin, G.N.; Landon, M.K.
1996-01-01
Detailed vertical sampling is useful in aquifers where vertical mixing is limited and steep vertical gradients in chemical concentrations are expected. Samples can be collected at closely spaced vertical intervals from nested wells with short screened intervals. However, this approach may not be appropriate in all situations. An easy-to-construct and easy-to-install multiport sampling well to collect ground-water samples from closely spaced vertical intervals was developed and tested. The multiport sampling well was designed to sample ground water from surficial sand-and-gravel aquifers. The device consists of multiple stainless-steel tubes within a polyvinyl chloride (PVC) protective casing. The tubes protrude through the wall of the PVC casing at the desired sampling depths. A peristaltic pump is used to collect ground-water samples from the sampling ports. The difference in hydraulic head between any two sampling ports can be measured with a vacuum pump and a modified manometer. The usefulness and versatility of this multiport well design was demonstrated at an agricultural research site near Princeton, Minnesota where sampling ports were installed to a maximum depth of about 12 m below land surface. Tracer experiments were conducted using potassium bromide to document the degree to which short-circuiting occurred between sampling ports. Samples were successfully collected for analysis of major cations and anions, nutrients, selected herbicides, isotopes, dissolved gases, and chlorofluorcarbon concentrations.
Multiport well design for sampling of ground water at closely spaced vertical intervals
Delin, G.N.; Landon, M.K.
1996-11-01
Detailed vertical sampling is useful in aquifers where vertical mixing is limited and steep vertical gradients in chemical concentrations are expected. Samples can be collected at closely spaced vertical intervals from nested wells with short screened intervals. However, this approach may not be appropriate in all situations. An easy-to-construct and easy-to-install multiport sampling well to collect ground-water samples from closely spaced vertical intervals was developed and tested. The multiport sampling well was designed to sample ground water from surficial sand-and-gravel aquifers. The device consists of multiple stainless-steel tubes within a polyvinyl chloride (PVC) protective casing. The tubes protrude through the wall of the PVC casing at the desired sampling depths. A peristaltic pump is used to collect ground-water samples form the sampling ports. The difference in hydraulic head between any two sampling ports can be measured with a vacuum pump and a modified manometer. The usefulness and versatility of this multiport well design was demonstrated at an agricultural research site near Princeton, Minnesota where sampling ports were installed to a maximum depth of about 12 m below land surface. Trace experiments were conducted using potassium bromide to document the degree to which short-circuiting occurred between sampling ports. Samples were successfully collected for analysis of major cations and anions, nutrients, selected herbicides, isotopes, dissolved gases, and chlorofluorocarbon concentrations.
Interval Estimation of Standardized Mean Differences in Paired-Samples Designs
ERIC Educational Resources Information Center
Bonett, Douglas G.
2015-01-01
Paired-samples designs are used frequently in educational and behavioral research. In applications where the response variable is quantitative, researchers are encouraged to supplement the results of a paired-samples t-test with a confidence interval (CI) for a mean difference or a standardized mean difference. Six CIs for standardized mean…
Sample Size for Confidence Interval of Covariate-Adjusted Mean Difference
ERIC Educational Resources Information Center
Liu, Xiaofeng Steven
2010-01-01
This article provides a way to determine adequate sample size for the confidence interval of covariate-adjusted mean difference in randomized experiments. The standard error of adjusted mean difference depends on covariate variance and balance, which are two unknown quantities at the stage of planning sample size. If covariate observations are…
Interval Estimation of Standardized Mean Differences in Paired-Samples Designs
ERIC Educational Resources Information Center
Bonett, Douglas G.
2015-01-01
Paired-samples designs are used frequently in educational and behavioral research. In applications where the response variable is quantitative, researchers are encouraged to supplement the results of a paired-samples t-test with a confidence interval (CI) for a mean difference or a standardized mean difference. Six CIs for standardized mean…
Sample Size for Confidence Interval of Covariate-Adjusted Mean Difference
ERIC Educational Resources Information Center
Liu, Xiaofeng Steven
2010-01-01
This article provides a way to determine adequate sample size for the confidence interval of covariate-adjusted mean difference in randomized experiments. The standard error of adjusted mean difference depends on covariate variance and balance, which are two unknown quantities at the stage of planning sample size. If covariate observations are…
The Naive Intuitive Statistician: A Naive Sampling Model of Intuitive Confidence Intervals
ERIC Educational Resources Information Center
Juslin, Peter; Winman, Anders; Hansson, Patrik
2007-01-01
The perspective of the naive intuitive statistician is outlined and applied to explain overconfidence when people produce intuitive confidence intervals and why this format leads to more overconfidence than other formally equivalent formats. The naive sampling model implies that people accurately describe the sample information they have but are…
Sample size and the width of the confidence interval for mean difference.
Liu, Xiaofeng Steven
2009-05-01
The width of the confidence interval for mean difference can be viewed as a random variable. Overlooking its stochastic nature may lead to a serious underestimate of the sample size required to obtain an adequate probability of achieving the desired width for the confidence interval. The probability of achieving a certain width can either be an unconditional probability or a conditional probability given that the confidence interval includes the true parameter. We reconciled the difference between the unconditional and conditional probabilities by deriving the lower bound of the conditional probability. Additionally, we used the harmonic mean to determine unequal sample sizes for the confidence intervals for the two-mean comparison and multiple-mean comparisons.
A new method for choosing sample size for confidence interval-based inferences.
Jiroutek, Michael R; Muller, Keith E; Kupper, Lawrence L; Stewart, Paul W
2003-09-01
Scientists often need to test hypotheses and construct corresponding confidence intervals. In designing a study to test a particular null hypothesis, traditional methods lead to a sample size large enough to provide sufficient statistical power. In contrast, traditional methods based on constructing a confidence interval lead to a sample size likely to control the width of the interval. With either approach, a sample size so large as to waste resources or introduce ethical concerns is undesirable. This work was motivated by the concern that existing sample size methods often make it difficult for scientists to achieve their actual goals. We focus on situations which involve a fixed, unknown scalar parameter representing the true state of nature. The width of the confidence interval is defined as the difference between the (random) upper and lower bounds. An event width is said to occur if the observed confidence interval width is less than a fixed constant chosen a priori. An event validity is said to occur if the parameter of interest is contained between the observed upper and lower confidence interval bounds. An event rejection is said to occur if the confidence interval excludes the null value of the parameter. In our opinion, scientists often implicitly seek to have all three occur: width, validity, and rejection. New results illustrate that neglecting rejection or width (and less so validity) often provides a sample size with a low probability of the simultaneous occurrence of all three events. We recommend considering all three events simultaneously when choosing a criterion for determining a sample size. We provide new theoretical results for any scalar (mean) parameter in a general linear model with Gaussian errors and fixed predictors. Convenient computational forms are included, as well as numerical examples to illustrate our methods.
The influence of sampling interval on the accuracy of trail impact assessment
Leung, Y.-F.; Marion, J.L.
1999-01-01
Trail impact assessment and monitoring (IA&M) programs have been growing in importance and application in recreation resource management at protected areas. Census-based and sampling-based approaches have been developed in such programs, with systematic point sampling being the most common survey design. This paper examines the influence of sampling interval on the accuracy of estimates for selected trail impact problems. A complete census of four impact types on 70 trails in Great Smoky Mountains National Park was utilized as the base data set for the analyses. The census data were resampled at increasing intervals to create a series of simulated point data sets. Estimates of frequency of occurrence and lineal extent for the four impact types were compared with the census data set. The responses of accuracy loss on lineal extent estimates to increasing sampling intervals varied across different impact types, while the responses on frequency of occurrence estimates were consistent, approximating an inverse asymptotic curve. These findings suggest that systematic point sampling may be an appropriate method for estimating the lineal extent but not the frequency of trail impacts. Sample intervals of less than 100 m appear to yield an excellent level of accuracy for the four impact types evaluated. Multiple regression analysis results suggest that appropriate sampling intervals are more likely to be determined by the type of impact in question rather than the length of trail. The census-based trail survey and the resampling-simulation method developed in this study can be a valuable first step in establishing long-term trail IA&M programs, in which an optimal sampling interval range with acceptable accuracy is determined before investing efforts in data collection.
Confidence interval construction for proportion difference in small-sample paired studies.
Tang, Man-Lai; Tang, Nian-Sheng; Chan, Ivan S F
2005-12-15
Paired dichotomous data may arise in clinical trials such as pre-/post-test comparison studies and equivalence trials. Reporting parameter estimates (e.g. odds ratio, rate difference and rate ratio) along with their associated confidence interval estimates becomes a necessity in many medical journals. Various asymptotic confidence interval estimators have long been developed for differences in correlated binary proportions. Nevertheless, the performance of these asymptotic methods may have poor coverage properties in small samples. In this article, we investigate several alternative confidence interval estimators for the difference between binomial proportions based on small-sample paired data. Specifically, we consider exact and approximate unconditional confidence intervals for rate difference via inverting a score test. The exact unconditional confidence interval guarantees the coverage probability, and it is recommended if strict control of coverage probability is required. However, the exact method tends to be overly conservative and computationally demanding. Our empirical results show that the approximate unconditional score confidence interval estimators based on inverting the score test demonstrate reasonably good coverage properties even in small-sample designs, and yet they are relatively easy to implement computationally. We illustrate the methods using real examples from a pain management study and a cancer study.
Meany-Daboul, Maeve G; Roscoe, Eileen M; Bourret, Jason C; Ahearn, William H
2007-01-01
In the current study, momentary time sampling (MTS) and partial-interval recording (PIR) were compared to continuous-duration recording of stereotypy and to the frequency of self-injury during a treatment analysis to determine whether the recording method affected data interpretation. Five previously conducted treatment analysis data sets were analyzed by creating separate graphic displays for each measurement method (duration or frequency, MTS, and PIR). An expert panel interview and structured criterion visual inspection were used to evaluate treatment effects across measurement methods. Results showed that treatment analysis interpretations based on both discontinuous recording methods often matched those based on frequency or duration recording; however, interpretations based on MTS were slightly more likely to match those based on duration and those based on PIR were slightly more likely to match those based on frequency. PMID:17970263
Hatjimihail, Aristides T
2009-06-09
An open problem in clinical chemistry is the estimation of the optimal sampling time intervals for the application of statistical quality control (QC) procedures that are based on the measurement of control materials. This is a probabilistic risk assessment problem that requires reliability analysis of the analytical system, and the estimation of the risk caused by the measurement error. Assuming that the states of the analytical system are the reliability state, the maintenance state, the critical-failure modes and their combinations, we can define risk functions based on the mean time of the states, their measurement error and the medically acceptable measurement error. Consequently, a residual risk measure rr can be defined for each sampling time interval. The rr depends on the state probability vectors of the analytical system, the state transition probability matrices before and after each application of the QC procedure and the state mean time matrices. As optimal sampling time intervals can be defined those minimizing a QC related cost measure while the rr is acceptable. I developed an algorithm that estimates the rr for any QC sampling time interval of a QC procedure applied to analytical systems with an arbitrary number of critical-failure modes, assuming any failure time and measurement error probability density function for each mode. Furthermore, given the acceptable rr, it can estimate the optimal QC sampling time intervals. It is possible to rationally estimate the optimal QC sampling time intervals of an analytical system to sustain an acceptable residual risk with the minimum QC related cost. For the optimization the reliability analysis of the analytical system and the risk analysis of the measurement error are needed.
Estimating fluvial wood discharge from timelapse photography with varying sampling intervals
NASA Astrophysics Data System (ADS)
Anderson, N. K.
2013-12-01
There is recent focus on calculating wood budgets for streams and rivers to help inform management decisions, ecological studies and carbon/nutrient cycling models. Most work has measured in situ wood in temporary storage along stream banks or estimated wood inputs from banks. Little effort has been employed monitoring and quantifying wood in transport during high flows. This paper outlines a procedure for estimating total seasonal wood loads using non-continuous coarse interval sampling and examines differences in estimation between sampling at 1, 5, 10 and 15 minutes. Analysis is performed on wood transport for the Slave River in Northwest Territories, Canada. Relative to the 1 minute dataset, precision decreased by 23%, 46% and 60% for the 5, 10 and 15 minute datasets, respectively. Five and 10 minute sampling intervals provided unbiased equal variance estimates of 1 minute sampling, whereas 15 minute intervals were biased towards underestimation by 6%. Stratifying estimates by day and by discharge increased precision over non-stratification by 4% and 3%, respectively. Not including wood transported during ice break-up, the total minimum wood load estimated at this site is 3300 × 800$ m3 for the 2012 runoff season. The vast majority of the imprecision in total wood volumes came from variance in estimating average volume per log. Comparison of proportions and variance across sample intervals using bootstrap sampling to achieve equal n. Each trial was sampled for n=100, 10,000 times and averaged. All trials were then averaged to obtain an estimate for each sample interval. Dashed lines represent values from the one minute dataset.
Neyman-Pearson and Bayes interval estimates for sampling by attributes
Mason, R.M.; Ryl, P.; Williams, J.W.
1984-12-01
This paper compares confidence intervals for single and multistage sampling schemes with Bayesian interval estimates obtained with a uniform prior distribution. Examples are presented in graphical form for sampling by attributes from an infinite population, or from a finite population with replacement. A general proof is given that the Neyman-Pearson confidence level associated with a confidence interval for the binomial parameter p will be no greater than the Bayesian confidence level calculated using a uniform prior distribution. A demonstration is provided for a fact published earlier, viz., that the Bayesian prior distribution can be selected so as to provide equality between one-sided Neyman-Pearson and Bayesian confidence bounds. Applications to EMP analysis are discussed in the final section.
Analysis of single ion channel data incorporating time-interval omission and sampling.
The, Yu-Kai; Timmer, Jens
2006-02-22
Hidden Markov models are widely used to describe single channel currents from patch-clamp experiments. The inevitable anti-aliasing filter limits the time resolution of the measurements and therefore the standard hidden Markov model is not adequate anymore. The notion of time-interval omission has been introduced where brief events are not detected. The developed, exact solutions to this problem do not take into account that the measured intervals are limited by the sampling time. In this case the dead-time that specifies the minimal detectable interval length is not defined unambiguously. We show that a wrong choice of the dead-time leads to considerably biased estimates and present the appropriate equations to describe sampled data.
Pan, Z; Kupper, L L
1999-06-30
Methods for optimal sample size determination are developed using four popular multiple comparison procedures (Scheffe's, Bonferroni's, Tukey's and Dunnett's procedures), where random samples of the same size n are to be selected from k (>/=2) normal populations with common variance sigma2, and where primary interest concerns inferences about a family of L linear contrasts among the k population means. For a simultaneous coverage probability of (1-alpha), the optimal sample size is defined to be the smallest integer value n*m such that, simultaneously for all L confidence intervals, the width of the lth confidence interval will be no greater than tolerance 2deltal (l=1,2,...,L) with tolerance probability at least (1-gamma), treating the pooled sample variance S2p as a random variable. Using Scheffe's procedure as an illustration, comparisons are made to usual sample size methods that incorrectly ignore the stochastic nature of S2p. The latter approach can lead to serious underestimation of required sample sizes and hence to unacceptably low values of the actually tolerance probability (1-gamma'). Our approach guarantees a lower bound of [1-(alpha+gamma)] for the probability that the L confidence intervals will both cover the parametric functions of interest and also be sufficiently narrow. Recommendations are provided regarding the choices among the four multiple comparison procedures for sample size determination and inference-making. Copyright 1999 John Wiley & Sons, Ltd.
ERIC Educational Resources Information Center
Zakszeski, Brittany N.; Hojnoski, Robin L.; Wood, Brenna K.
2017-01-01
Classroom engagement is important to young children's academic and social development. Accurate methods of capturing this behavior are needed to inform and evaluate intervention efforts. This study compared the accuracy of interval durations (i.e., 5 s, 10 s, 15 s, 20 s, 30 s, and 60 s) of momentary time sampling (MTS) in approximating the…
Eight interval estimators of a common rate ratio under stratified Poisson sampling.
Lui, Kung-Jong
2004-04-30
Under the assumption that the rate ratio (RR) is constant across strata, we consider eight interval estimators of RR under stratified Poisson sampling: the weighted least-squares (WLS) interval estimator with the logarithmic transformation, the interval estimator using the principle analogous to that of Fieller's Theorem, the interval estimators using Wald's statistic with and without the logarithmic transformation, the interval estimators using the Mantel-Haenszel statistic with and without the logarithmic transformation, the score test-based interval estimator, and the asymptotic likelihood ratio test-based interval estimator. We apply Monte Carlo simulation to evaluate and compare the performance of these estimators with respect to the coverage probability and the average length in a variety of situations. We find that the coverage probability of the commonly used WLS interval estimator tends to be smaller than the desired confidence level, especially when we have a large number of strata with a small expected total number of cases (ETNC) per stratum and the underlying RR is far away from 1 (i.e. RR18 or RR8). We further find that the two estimators with the logarithmic transformation, as well as the two test-based estimators can consistently perform well in a variety of situations. When RR1 with a given reasonable size of ETNC per stratum, we note that the interval estimators without the logarithmic transformation can be preferable to the corresponding ones with the logarithmic transformation in the situations considered here. However, when evaluating the non-coverage probability in the two tails, we find that the former tends to shift the left, while the latter is generally not subject to this concern. We also note that interval estimator using the Mantel-Haenszel (MH) statistic with the logarithmic transformation is likely less efficient than the two test-based interval estimators using the score and the likelihood ratio tests. Finally, we use the data taken
Wang, Rui; Lagakos, Stephen W; Gray, Robert J
2010-10-01
While the commonly used log-rank test for survival times between 2 groups enjoys many desirable properties, sometimes the log-rank test and its related linear rank tests perform poorly when sample sizes are small. Similar concerns apply to interval estimates for treatment differences in this setting, though their properties are less well known. Standard permutation tests are one option, but these are not in general valid when the underlying censoring distributions in the comparison groups are unequal. We develop 2 methods for testing and interval estimation, for use with small samples and possibly unequal censoring, based on first imputing survival and censoring times and then applying permutation methods. One provides a heuristic justification for the approach proposed recently by Heinze and others (2003, Exact log-rank tests for unequal follow-up. Biometrics 59, 1151-1157). Simulation studies show that the proposed methods have good Type I error and power properties. For accelerated failure time models, compared to the asymptotic methods of Jin and others (2003, Rank-based inference for the accelerated failure time model. Biometrika 90, 341-353), the proposed methods yield confidence intervals with better coverage probabilities in small-sample settings and similar efficiency when sample sizes are large. The proposed methods are illustrated with data from a cancer study and an AIDS clinical trial.
Confidence Intervals for the Overall Effect Size in Random-Effects Meta-Analysis
ERIC Educational Resources Information Center
Sanchez-Meca, Julio; Marin-Martinez, Fulgencio
2008-01-01
One of the main objectives in meta-analysis is to estimate the overall effect size by calculating a confidence interval (CI). The usual procedure consists of assuming a standard normal distribution and a sampling variance defined as the inverse of the sum of the estimated weights of the effect sizes. But this procedure does not take into account…
Confidence Intervals for Effect Sizes: Applying Bootstrap Resampling
ERIC Educational Resources Information Center
Banjanovic, Erin S.; Osborne, Jason W.
2016-01-01
Confidence intervals for effect sizes (CIES) provide readers with an estimate of the strength of a reported statistic as well as the relative precision of the point estimate. These statistics offer more information and context than null hypothesis statistic testing. Although confidence intervals have been recommended by scholars for many years,…
Reporting Confidence Intervals and Effect Sizes: Collecting the Evidence
ERIC Educational Resources Information Center
Zientek, Linda Reichwein; Ozel, Z. Ebrar Yetkiner; Ozel, Serkan; Allen, Jeff
2012-01-01
Confidence intervals (CIs) and effect sizes are essential to encourage meta-analytic thinking and to accumulate research findings. CIs provide a range of plausible values for population parameters with a degree of confidence that the parameter is in that particular interval. CIs also give information about how precise the estimates are. Comparison…
Confidence Intervals for Effect Sizes: Applying Bootstrap Resampling
ERIC Educational Resources Information Center
Banjanovic, Erin S.; Osborne, Jason W.
2016-01-01
Confidence intervals for effect sizes (CIES) provide readers with an estimate of the strength of a reported statistic as well as the relative precision of the point estimate. These statistics offer more information and context than null hypothesis statistic testing. Although confidence intervals have been recommended by scholars for many years,…
Reporting Confidence Intervals and Effect Sizes: Collecting the Evidence
ERIC Educational Resources Information Center
Zientek, Linda Reichwein; Ozel, Z. Ebrar Yetkiner; Ozel, Serkan; Allen, Jeff
2012-01-01
Confidence intervals (CIs) and effect sizes are essential to encourage meta-analytic thinking and to accumulate research findings. CIs provide a range of plausible values for population parameters with a degree of confidence that the parameter is in that particular interval. CIs also give information about how precise the estimates are. Comparison…
The Use of One-Sample Prediction Intervals for Estimating CO2 Scrubber Canister Durations
2012-10-01
testing) that describe the characteristics of carbon dioxide absorbent canisters in closed - and semiclosed- circuit UBAs ( rebreathers ). The...CONCLUSIONS As described in engineering statistics texts, the use of one-sample prediction intervals is profitably applied to the testing of closed - circuit ...Duration Limits for Closed - Circuit Underwater Breathing Apparatus, NEDU TR 2-99, Navy Experimental Diving Unit, April 1999. 2. J. Clarke, K
Bolboacă, Sorana; Jäntschi, Lorentz
2005-01-01
Likelihood Ratio medical key parameters calculated on categorical results from diagnostic tests are usually express accompanied with their confidence intervals, computed using the normal distribution approximation of binomial distribution. The approximation creates known anomalies,especially for limit cases. In order to improve the quality of estimation, four new methods (called here RPAC, RPAC0, RPAC1, and RPAC2) were developed and compared with the classical method (called here RPWald), using an exact probability calculation algorithm.Computer implementations of the methods use the PHP language. We defined and implemented the functions of the four new methods and the five criterions of confidence interval assessment. The experiments run for samples sizes which vary in 14 - 34 range, 90 - 100 range (0 < X < m, 0< Y < n), as well as for random numbers for samples sizes (4m, n interval for positive and negative likelihood ratios.
Confidence Interval Coverage for Cohen's Effect Size Statistic
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.; Penfield, Randall D.
2006-01-01
Kelley compared three methods for setting a confidence interval (CI) around Cohen's standardized mean difference statistic: the noncentral-"t"-based, percentile (PERC) bootstrap, and biased-corrected and accelerated (BCA) bootstrap methods under three conditions of nonnormality, eight cases of sample size, and six cases of population…
Effectiveness of Interval Exercise Training in Patients with COPD
Kortianou, Eleni A.; Nasis, Ioannis G.; Spetsioti, Stavroula T.; Daskalakis, Andreas M.; Vogiatzis, Ioannis
2010-01-01
Physical training is beneficial and should be included in the comprehensive management of all patients with COPD independently of disease severity. Different rehabilitative strategies and training modalities have been proposed to optimize exercise tolerance. Interval exercise training has been used as an effective alternative modality to continuous exercise in patients with moderate and severe COPD. Although in healthy elderly individuals and patients with chronic heart failure there is evidence that this training modality is superior to continuous exercise in terms of physiological training effects, in patients with COPD, there is not such evidence. Nevertheless, in patients with COPD application of interval training has been shown to be equally effective to continuous exercise as it induces equivalent physiological training effects but with less symptoms of dyspnea and leg discomfort during training. The main purpose of this review is to summarize previous studies of the effectiveness of interval training in COPD and also to provide arguments in support of the application of interval training to overcome the respiratory and peripheral muscle limiting factors of exercise capacity. To this end we make recommendations on how best to implement interval training in the COPD population in the rehabilitation setting so as to maximize training effects. PMID:20957074
A Self-Contained Pole Syringe Array for Closed-Interval Water Sampling.
1982-10-19
L AD-R12l 265 R SELF-CONTAINED POLE SYRINGE ARRAY FOR CLOSDITRR Va WATER SANPLING4U) NAVAL RESEARCH LAB WASHINGTON DC I R E PELLENBARG ET AL. 19 OCT...PERIOD COVERED A SELF-CONTAINED POLE SYRINGE ARRAY FOR Interim report on one phase of CLOSED-INTERVAL WATER SAMPLING an NRL problem. 6. PERFORMING ORG...1473 EDITION OF I NOv ,, IS OMSOLCT S/N 0102-014- 6601 SECURITY CLASSIFICATION OF THIS PAGE (Wm Dle Et ere d A SELF-CONTAINED POLE SYRINGE ARRAY FOR
Finite sample pointwise confidence intervals for a survival distribution with right-censored data.
Fay, Michael P; Brittain, Erica H
2016-07-20
We review and develop pointwise confidence intervals for a survival distribution with right-censored data for small samples, assuming only independence of censoring and survival. When there is no censoring, at each fixed time point, the problem reduces to making inferences about a binomial parameter. In this case, the recently developed beta product confidence procedure (BPCP) gives the standard exact central binomial confidence intervals of Clopper and Pearson. Additionally, the BPCP has been shown to be exact (gives guaranteed coverage at the nominal level) for progressive type II censoring and has been shown by simulation to be exact for general independent right censoring. In this paper, we modify the BPCP to create a 'mid-p' version, which reduces to the mid-p confidence interval for a binomial parameter when there is no censoring. We perform extensive simulations on both the standard and mid-p BPCP using a method of moments implementation that enforces monotonicity over time. All simulated scenarios suggest that the standard BPCP is exact. The mid-p BPCP, like other mid-p confidence intervals, has simulated coverage closer to the nominal level but may not be exact for all survival times, especially in very low censoring scenarios. In contrast, the two asymptotically-based approximations have lower than nominal coverage in many scenarios. This poor coverage is due to the extreme inflation of the lower error rates, although the upper limits are very conservative. Both the standard and the mid-p BPCP methods are available in our bpcp R package. Published 2016. This article is US Government work and is in the public domain in the USA.
Confidence intervals for effect parameters common in cancer epidemiology.
Sato, T
1990-01-01
This paper reviews approximate confidence intervals for some effect parameters common in cancer epidemiology. These methods have computational feasibility and give nearly nominal coverage rates. In the analysis of crude data, the simplest type of epidemiologic analysis, parameters of interest are the odds ratio in case-control studies and the rate ratio and difference in cohort studies. These parameters can estimate the instantaneous-incidence-rate ratio and difference that are the most meaningful effect measures in cancer epidemiology. Approximate confidence intervals for these parameters including the classical Cornfield's method are mainly based on efficient scores. When some confounding factors exist, stratified analysis and summary measures for effect parameters are needed. Since the Mantel-Haenszel estimators have been widely used by epidemiologists as summary measures, confidence intervals based on the Mantel-Haenszel estimators are described. The paper also discusses recent developments in these methods. PMID:2269246
The use of latin hypercube sampling for the efficient estimation of confidence intervals
Grabaskas, D.; Denning, R.; Aldemir, T.; Nakayama, M. K.
2012-07-01
Latin hypercube sampling (LHS) has long been used as a way of assuring adequate sampling of the tails of distributions in a Monte Carlo analysis and provided the framework for the uncertainty analysis performed in the NUREG-1150 risk assessment. However, this technique has not often been used in the performance of regulatory analyses due to the inability to establish confidence levels on the quantiles of the output distribution. Recent work has demonstrated a method that makes this possible. This method is compared to the procedure of crude Monte Carlo using order statistics, which is currently used to establish confidence levels. The results of several statistical examples demonstrate that the LHS confidence interval method can provide a more accurate and precise solution, but issues remain when applying the technique generally. (authors)
Application of MALDI-TOF MS for Estimating the Postmortem Interval in Rat Muscle Samples.
Li, Chengzhi; Ma, Dong; Deng, Kaifei; Chen, Yijiu; Huang, Ping; Wang, Zhenyuan
2017-09-01
Estimating the postmortem interval (PMI) is very important in the forensic sciences. Although many approaches have been used for estimating the PMI, accurate PMI calculations are still difficult. In this study, four Sprague Dawley (SD) rats were sacrificed by suffocation, and muscle samples were collected by dissection at various time intervals (0, 48, 96, and 144 h) after death. All samples were probed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to obtain molecular images and data for principal component analysis (PCA). The results showed that the peaks at m/z 1511, 1543, 1564, 1586 clearly decreased in intensity from 0 to 144 h postmortem and that the time groups were separated from each other on the PCA score plot. The prediction model showed high recognition capability (95.93%) and cross-validation (83.72%). Our work suggests that MALDI-TOF MS can be used to determine the PMI. © 2017 American Academy of Forensic Sciences.
NASA Astrophysics Data System (ADS)
Wang, Lin-Jie; Cheng, Tan; Zhi-Li, Li; Hui-juan, Wang; Wen-juan, Chen; Jianfeng, Zhang; Desheng, Wang; Dongbin, Niu; Qi, Zhao; Chengjia, Yang; Yanqing, Wang
High intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. But the difference between high intensity interval training and moderate intensity interval training (MIIT) in simulated weightlessness still has not been well studied. This study sought to characterize the difference between 6 weeks high intensity interval training and moderate intensity interval training under reduced weight (RW) gait training device and zero-gravity locomotion system (ZLS). Twenty-three subjects (14M/4F, 32.5±4.5 years) volunteered to participate. They were divided into three groups, that were MITT (alternating 2 min at 40% VO _{2} peak and 2 min at 60% VO _{2} peak for 30min, five days per week) RW group (n=8), HITT (alternating 2 min at 40% VO _{2} peak and 2 min at 90% VO _{2} peak for 30min, three days per week) RW group (n=8) and HITT ZLS group (n=7). The Z-axis load used in RW group was 80% body weight (BW) and in ZLS was 100% BW. Cardiopulmonary function was measured before, after 4-week training and after 6-week training. Isokinetic knee extension-flexion test at 60(°) deg/s and 180(°) deg/s were performed before and after the 6-week training, and isometric knee extension-flexion test at 180(°) deg/s was also examined at the same time. It was found that the VO _{2} peaks, metabolic equivalent (MET), Speedmax and respiratory exchange ratio (RER) were significantly increased after 4 and 6-week training in all three groups and no significant group difference were detected. The peak torque at 60(°) deg/s for right knee flexion were significantly increased after 6 week-training in all three groups, and only in HITT RW group the total power at 60(°) deg/s for right knee flexion enhanced. The total power and average power at 60(°) deg/s for right knee extension decreased significantly after 6-week training in all three groups. The peak torque at 60(°) deg/s for right knee extension in MIIT RW group was
Power and sample size calculations for interval-censored survival analysis.
Kim, Hae-Young; Williamson, John M; Lin, Hung-Mo
2016-04-15
We propose a method for calculating power and sample size for studies involving interval-censored failure time data that only involves standard software required for fitting the appropriate parametric survival model. We use the framework of a longitudinal study where patients are assessed periodically for a response and the only resultant information available to the investigators is the failure window: the time between the last negative and first positive test results. The survival model is fit to an expanded data set using easily computed weights. We illustrate with a Weibull survival model and a two-group comparison. The investigator can specify a group difference in terms of a hazards ratio. Our simulation results demonstrate the merits of these proposed power calculations. We also explore how the number of assessments (visits), and thus the corresponding lengths of the failure intervals, affect study power. The proposed method can be easily extended to more complex study designs and a variety of survival and censoring distributions. Copyright © 2015 John Wiley & Sons, Ltd.
Wang, Wei; Zhuge, Qunbi; Morsy-Osman, Mohamed; Gao, Yuliang; Xu, Xian; Chagnon, Mathieu; Qiu, Meng; Hoang, Minh Thang; Zhang, Fangyuan; Li, Rui; Plant, David V
2014-11-03
We propose a decision-aided algorithm to compensate the sampling frequency offset (SFO) between the transmitter and receiver for reduced-guard-interval (RGI) coherent optical (CO) OFDM systems. In this paper, we first derive the cyclic prefix (CP) requirement for preventing OFDM symbols from SFO induced inter-symbol interference (ISI). Then we propose a new decision-aided SFO compensation (DA-SFOC) algorithm, which shows a high SFO tolerance and reduces the CP requirement. The performance of DA-SFOC is numerically investigated for various situations. Finally, the proposed algorithm is verified in a single channel 28 Gbaud polarization division multiplexing (PDM) RGI CO-OFDM experiment with QPSK, 8 QAM and 16 QAM modulation formats, respectively. Both numerical and experimental results show that the proposed DA-SFOC method is highly robust against the standard SFO in optical fiber transmission.
Ledgerwood, D N; Winckler, C; Tucker, C B
2010-11-01
Lying behavior in dairy cattle can provide insight into how cows interact with their environment. Although lying behavior is a useful indicator of cow comfort, it can be time consuming to measure. In response to these time constraints, using data loggers to automate behavioral recording has become increasingly common. We tested the accuracy of the Onset Pendant G data logger (Onset Computer Corporation, Bourne, MA) for measuring lying behavior in dairy cattle (n=24 cows; 12 in each of 2 experiments). Cows wore the logger on the lateral (experiment 1) or medial (experiment 2) side of the hind leg above the metatarsophalangeal joint. Loggers recorded behavior at 4 sampling intervals (6, 30, 60, and 300 s) for at least 1.5 d. Data were smoothed using 3 editing methods to examine the effects of short, potentially erroneous readings. For this purpose, Microsoft Excel macros (Microsoft Corp., Redmond, WA) converted readings (i.e., lying events bordered by standing or vice versa) occurring singly or in consecutive runs of ≤2 or ≤6. Behavior was simultaneously recorded with digital video equipment. The logger accurately measured lying and standing. For example, predictability, sensitivity, and specificity were >99% using 30-s sampling and the single-event filter compared with continuously scored video recordings. The 6- and 30-s sampling intervals were comparable for all aspects of lying behavior when short events were filtered from the data set. Estimates of lying time generated from the 300-s interval unfiltered regimen were positively related (R(2) ≥ 0.99) to estimates of lying time from video, but this sampling regimen overestimated the number of lying bouts. This is likely because short standing and lying bouts were missed (12 and 34% of lying and standing bouts were <300 s in experiment 1 and 2, respectively). In summary, the data logger accurately measured all aspects of lying behavior when the sampling interval was ≤30 s and when short readings of lying and
[The importance of the sample design effect].
Guillén, Montserrat; Ayuso, Mercedes
2004-01-01
Sample selection through a complex design influences the subsequent statistical analysis. The different means of sample selection may result in bias and greater variance of estimators; simple randomized sampling is the reference design. Diverse examples are provided, illustrating how the various sampling strategies can result in bias and increase variance. The inclusion of different weighting techniques reduces bias. Evaluation of the effect of design enables measurement of the degree of variance distortion due to the sampling design used and therefore provides a direct evaluation of the alteration in the confidence intervals estimated when the sampling design deviates from simple randomized sampling. We recommend measurement of the effect of the design on analysis of the data obtained by sampling and inclusion of weighting techniques in statistical analyses.
Contrasting effects of interference and of breaks in interval timing.
Gaudreault, Rémi; Fortin, Claudette; Macar, Françoise
2010-01-01
When a break is introduced during an interval to be timed, the interval is perceived shorter as break location is delayed. This is interpreted as a result of attention sharing between timing and monitoring the source of the break signal. Similar effects and interpretations are found in another context involving interfering tasks. Such tasks are assumed to induce transient interruptions in timing, comparable to those obtained with breaks. Break and interference conditions were contrasted in a temporal reproduction procedure with identical stimuli. Both conditions induced temporal underestimation and similar location effects. Similar trends occurred in a control condition where no processing of the interfering signal was required. The data suggest that expectancy, intentional processing, and automatic attraction of attention shorten temporal estimates.
Liu, Su-Hsun; Cummings, Derek AT; Zenilman, Jonathan M; Gravitt, Patti E; Brotman, Rebecca M
2013-01-01
Background Variable detection of human papillomavirus (HPV) DNA can result in misclassification of infection status, but the extent of misclassification has not been quantitatively evaluated. Methods In 2005–2007, 33 women aged 22–53 self-collected vaginal swabs twice per week for 16 consecutive weeks. Each of the 955 swabs collected was tested for 37 HPV types/subtypes. Assuming that a woman’s underlying infection status did not change over the short study period, biases in prevalence estimates obtained from single versus multiple swabs were calculated. Using event history analysis methods, time to recurrent gain and loss of at least one HPV type was determined, separately. Baseline any- and high risk-HPV prevalence was 60.6% and 24.2%, respectively. Cumulative any- and high risk-HPV prevalence over the 16-week period was 84.8% and 60.6%, separately. Results Overall, there were 319 events of detection and 313 events of loss of detection. Median times to a recurrent detection and loss of detection was 11 and 7 days, respectively. Neither vaginal sex nor condom use during follow-up was associated with recurrent viral detection or loss of detection. Assuming the cumulative 16-week prevalence reflects the true prevalence of infection, the baseline any-HPV prevalence under-estimated infection status by 24.2%, with a bootstrapped mean of 20.2% (95% confidence interval [CI]: 8.9%, 29.6%). Conclusions These findings suggest that a substantial proportion of HPV-infected women are misclassified as being un-infected when using a single-time DNA measurement. Impact Short-term variation in detectable HPV DNA needs to be considered while interpreting the natural history of infections using single samples collected at long intervals. PMID:24130223
Ward, Ryan D; Odum, Amy L
2006-02-28
This experiment investigated the effects of nonpharmacological disruption on temporal discrimination. Pigeons responded on a multiple schedule composed of fixed interval, color-matching, and temporal-discrimination components. The effects of three different disruptors (prefeeding, intercomponent-interval food, and extinction) were assessed. All disruptors decreased response rates during the fixed interval. Prefeeding and intercomponent-interval food had unsystematic effects on response patterning during the fixed interval, whereas extinction increased the relative response rate in the initial portions of the fixed interval. Accuracy of color matching was decreased by prefeeding and was not systematically affected by intercomponent-interval food and extinction. In the temporal-discrimination component, all disruptors flattened the psychophysical functions relating proportion long responses to sample duration. This result indicates a general disruption of temporal discrimination. In addition, parameter estimates derived from the behavioral theory of timing indicated all disruptors decreased pacemaker rate, a result consistent with the predictions of the theory. These results highlight the similarities between disruption of temporal discrimination by pharmacological and nonpharmacological manipulations.
Multivariate Effect Size Estimation: Confidence Interval Construction via Latent Variable Modeling
ERIC Educational Resources Information Center
Raykov, Tenko; Marcoulides, George A.
2010-01-01
A latent variable modeling method is outlined for constructing a confidence interval (CI) of a popular multivariate effect size measure. The procedure uses the conventional multivariate analysis of variance (MANOVA) setup and is applicable with large samples. The approach provides a population range of plausible values for the proportion of…
Multivariate Effect Size Estimation: Confidence Interval Construction via Latent Variable Modeling
ERIC Educational Resources Information Center
Raykov, Tenko; Marcoulides, George A.
2010-01-01
A latent variable modeling method is outlined for constructing a confidence interval (CI) of a popular multivariate effect size measure. The procedure uses the conventional multivariate analysis of variance (MANOVA) setup and is applicable with large samples. The approach provides a population range of plausible values for the proportion of…
ERIC Educational Resources Information Center
Hoekstra, Rink; Johnson, Addie; Kiers, Henk A. L.
2012-01-01
The use of confidence intervals (CIs) as an addition or as an alternative to null hypothesis significance testing (NHST) has been promoted as a means to make researchers more aware of the uncertainty that is inherent in statistical inference. Little is known, however, about whether presenting results via CIs affects how readers judge the…
ERIC Educational Resources Information Center
Hoekstra, Rink; Johnson, Addie; Kiers, Henk A. L.
2012-01-01
The use of confidence intervals (CIs) as an addition or as an alternative to null hypothesis significance testing (NHST) has been promoted as a means to make researchers more aware of the uncertainty that is inherent in statistical inference. Little is known, however, about whether presenting results via CIs affects how readers judge the…
Pigeons' Memory for Number of Events: Effects of Intertrial Interval and Delay Interval Illumination
ERIC Educational Resources Information Center
Hope, Chris; Santi, Angelo
2004-01-01
In Experiment 1, pigeons were trained at a 0-s baseline delay to discriminate sequences of light flashes (illumination of the feeder) that varied in number but not time (2f/4s and 8f/4s). During training, the intertrial interval was illuminated by the houselight for Group Light, but it was dark for Group Dark. Testing conducted with dark delay…
Nosewitness Identification: Effects of Lineup Size and Retention Interval
Alho, Laura; Soares, Sandra C.; Costa, Liliana P.; Pinto, Elisa; Ferreira, Jacqueline H. T.; Sorjonen, Kimmo; Silva, Carlos F.; Olsson, Mats J.
2016-01-01
Although canine identification of body odor (BO) has been widely used as forensic evidence, the concept of nosewitness identification by human observers was only recently put to the test. The results indicated that BOs associated with male characters in authentic crime videos could later be identified in BO lineup tests well above chance. To further evaluate nosewitness memory, we assessed the effects of lineup size (Experiment 1) and retention interval (Experiment 2), using a forced-choice memory test. The results showed that nosewitness identification works for all lineup sizes (3, 5, and 8 BOs), but that larger lineups compromise identification performance in similarity to observations from eye- and earwitness studies. Also in line with previous eye- and earwitness studies, but in disagreement with some studies on odor memory, Experiment 2 showed significant forgetting between shorter retention intervals (15 min) and longer retention intervals (1-week) using lineups of five BOs. Altogether this study shows that identification of BO in a forensic setting is possible and has limits and characteristics in line with witness identification through other sensory modalities. PMID:27303317
ERIC Educational Resources Information Center
Taylor, Matthew A.; Skourides, Andreas; Alvero, Alicia M.
2012-01-01
Interval recording procedures are used by persons who collect data through observation to estimate the cumulative occurrence and nonoccurrence of behavior/events. Although interval recording procedures can increase the efficiency of observational data collection, they can also induce error from the observer. In the present study, 50 observers were…
Rammsayer, Thomas H
2014-05-01
The present study was designed to investigate the influences of type of psychophysical task (two-alternative forced-choice [2AFC] and reminder tasks), type of interval (filled vs. empty), sensory modality (auditory vs. visual), and base duration (ranging from 100 through 1,000 ms) on performance on duration discrimination. All of these factors were systematically varied in an experiment comprising 192 participants. This approach allowed for obtaining information not only on the general (main) effect of each factor alone, but also on the functional interplay and mutual interactions of some or all of these factors combined. Temporal sensitivity was markedly higher for auditory than for visual intervals, as well as for the reminder relative to the 2AFC task. With regard to base duration, discrimination performance deteriorated with decreasing base durations for intervals below 400 ms, whereas longer intervals were not affected. No indication emerged that overall performance on duration discrimination was influenced by the type of interval, and only two significant interactions were apparent: Base Duration × Type of Interval and Base Duration × Sensory Modality. With filled intervals, the deteriorating effect of base duration was limited to very brief base durations, not exceeding 100 ms, whereas with empty intervals, temporal discriminability was also affected for the 200-ms base duration. Similarly, the performance decrement observed with visual relative to auditory intervals increased with decreasing base durations. These findings suggest that type of task, sensory modality, and base duration represent largely independent sources of variance for performance on duration discrimination that can be accounted for by distinct nontemporal mechanisms.
ERIC Educational Resources Information Center
Kelley, Ken
2008-01-01
Methods of sample size planning are developed from the accuracy in parameter approach in the multiple regression context in order to obtain a sufficiently narrow confidence interval for the population squared multiple correlation coefficient when regressors are random. Approximate and exact methods are developed that provide necessary sample size…
ERIC Educational Resources Information Center
Kelley, Ken
2008-01-01
Methods of sample size planning are developed from the accuracy in parameter approach in the multiple regression context in order to obtain a sufficiently narrow confidence interval for the population squared multiple correlation coefficient when regressors are random. Approximate and exact methods are developed that provide necessary sample size…
Whole-brain CT perfusion imaging using increased sampling intervals: A pilot study.
Cao, Guoquan; Chen, Weijian; Sun, Houzhang; Guo, Xianzhong; Yang, Yunjun; Tang, Kun; Liu, Jinjin
2017-09-01
The aim of the present study was to investigate the feasibility of whole-brain perfusion imaging using the increased sampling interval protocol for 320-detector row dynamic-volume computed tomography (CT). A total of 12 volunteers were recruited. The novel protocols with 11 volumes (defined as protocol P11) and 15 volumes (defined as protocol P15) were performed on the volunteers to evaluate whether P11 and P15 are able to acquire comparable results to the standard protocol with 19 volumes (defined as protocol P19) according to the as-low-as-reasonably-achievable principle. All data were acquired using a dynamic-volume CT scanner with a 16 cm-wide detector with 320 rows. The scanned transverse images from volunteers were analyzed using the Volume-Engineered System workstation. The MedCalc software package was used for Bland-Altman analysis of all variables. The data inconsistency of mean transit time (MTT), cerebral blood volume (CBV), cerebral blood flow (CBF), and time to peak (TTP) between P11/P15 and P19 were all <5%, and the data were trustworthy. The mean differences of MTT, CBV, CBF and TTP between P15 and P19 were less than those between P11 and P19. The consistencies of perfusion parameters acquired with protocols P15 and P19 were higher compared with those acquired with P11. In whole-brain perfusion, the new protocol P15 has higher consistency with P19 than P11, and the radiation dose may be reduced by ~16% without degradation of perfusion parameters. Therefore, P15 should be recommended as a routine procedure in whole-brain perfusion imaging.
Whole-brain CT perfusion imaging using increased sampling intervals: A pilot study
Cao, Guoquan; Chen, Weijian; Sun, Houzhang; Guo, Xianzhong; Yang, Yunjun; Tang, Kun; Liu, Jinjin
2017-01-01
The aim of the present study was to investigate the feasibility of whole-brain perfusion imaging using the increased sampling interval protocol for 320-detector row dynamic-volume computed tomography (CT). A total of 12 volunteers were recruited. The novel protocols with 11 volumes (defined as protocol P11) and 15 volumes (defined as protocol P15) were performed on the volunteers to evaluate whether P11 and P15 are able to acquire comparable results to the standard protocol with 19 volumes (defined as protocol P19) according to the as-low-as-reasonably-achievable principle. All data were acquired using a dynamic-volume CT scanner with a 16 cm-wide detector with 320 rows. The scanned transverse images from volunteers were analyzed using the Volume-Engineered System workstation. The MedCalc software package was used for Bland-Altman analysis of all variables. The data inconsistency of mean transit time (MTT), cerebral blood volume (CBV), cerebral blood flow (CBF), and time to peak (TTP) between P11/P15 and P19 were all <5%, and the data were trustworthy. The mean differences of MTT, CBV, CBF and TTP between P15 and P19 were less than those between P11 and P19. The consistencies of perfusion parameters acquired with protocols P15 and P19 were higher compared with those acquired with P11. In whole-brain perfusion, the new protocol P15 has higher consistency with P19 than P11, and the radiation dose may be reduced by ~16% without degradation of perfusion parameters. Therefore, P15 should be recommended as a routine procedure in whole-brain perfusion imaging. PMID:28962207
Acute effects of coffee on QT interval in healthy subjects
2011-01-01
The coronary endothelial function is recognized to have an important role in the physiology of the diastolic ventricular relaxation, a phase of the heart cycle that influences the electrocardiographic QT interval. Endothelial function is investigated in vivo by flow mediated dilation (FMD) in the brachial artery and has proven to be a strong predictor of both coronary endothelial function and cardiovascular events. It has been reported that coffee acutely induces FMD changes. In particular, the brachial artery FMD seems to decrease after caffeinated coffee (CC) and to increase after decaffeinated coffee (DC) ingestion. Since the cardiovascular effects of coffee are still a debated matter, this study aimed at investigating with a randomized, double-blind crossover design, if the QT interval of adult healthy subjects (19 males and 21 females) changes in the hour following CC or DC ingestion. Both systolic and diastolic blood pressure were higher in the hour following the ingestion of CC; the heart rate significantly increased 30 minutes after CC ingestion. A significant increase of the QT duration was observed one hour after DC ingestion (398.9 ± 3.8 vs 405.3 ± 3.7 msec; P < 0.05), not after CC. The QT interval corrected for heart rate did not significantly change following CC or DC ingestion. In conclusion, despite CC and DC previously demonstrated to influence the FMD they do not seem to induce a significant unfavourable acute change of the left ventricular repolarization. Further investigations are required to elucidate the effects of coffee in subjects with cardiovascular diseases. PMID:21288364
Shao, Jing; Fan, Liu-Yin; Cao, Cheng-Xi; Huang, Xian-Qing; Xu, Yu-Quan
2012-07-01
Interval free-flow zone electrophoresis (FFZE) has been used to suppress sample band broadening greatly hindering the development of free-flow electrophoresis (FFE). However, there has been still no quantitative study on the resolution increase of interval FFZE. Herein, we tried to make a comparison between bandwidths in interval FFZE and continuous one. A commercial dye with methyl green and crystal violet was well chosen to show the bandwidth. The comparative experiments were conducted under the same sample loading of the model dye (viz. 3.49, 1.75, 1.17, and 0.88 mg/h), the same running time (viz. 5, 10, 15, and 20 min), and the same flux ratio between sample and background buffer (= 10.64 × 10⁻³). Under the given conditions, the experiments demonstrated that (i) the band broadening was evidently caused by hydrodynamic factor in continuous mode, and (ii) the interval mode could clearly eliminate the hydrodynamic broadening existing in continuous mode, greatly increasing the resolution of dye separation. Finally, the interval FFZE was successfully used for the complete separation of two-model antibiotics (herein pyoluteorin and phenazine-1-carboxylic acid coexisting in fermentation broth of a new strain Pseudomonas aeruginosa M18), demonstrating the feasibility of interval FFZE mode for separation of biomolecules.
Welsh, J D; Payne, D L; Manion, C; Morrison, R D; Nichols, M A
1981-08-01
Interval sampling of breath hydrogen content was used in lactose malabsorbers: (1) to compare hydrogen responses following increasing oral doses of lactose in milk and aqueous solutions; (2) to determine the reproducibility of interval breath sampling, and (3) to compare carbohydrate malabsorption following ingestion of either regular milk or milk containing Lactobacillus acidophilus. Significant differences in breath hydrogen responses due to increasing amounts of lactose in milk and aqueous solutions were observed. The individual breath hydrogen responses were reproducible using the same lactose dose on different days. There was no significant difference in breath hydrogen responses or symptoms following administration of either regular milk or milk containing Lactobacillus acidophilus. Breath hydrogen sampling at intervals, as performed in these studies, provides a sensitive and reproducible index of lactose malabsorption.
Kelley, Ken
2008-01-01
Methods of sample size planning are developed from the accuracy in parameter approach in the multiple regression context in order to obtain a sufficiently narrow confidence interval for the population squared multiple correlation coefficient when regressors are random. Approximate and exact methods are developed that provide necessary sample size so that the expected width of the confidence interval will be sufficiently narrow. Modifications of these methods are then developed so that necessary sample size will lead to sufficiently narrow confidence intervals with no less than some desired degree of assurance. Computer routines have been developed and are included within the MBESS R package so that the methods discussed in the article can be implemented. The methods and computer routines are demonstrated using an empirical example linking innovation in the health services industry with previous innovation, personality factors, and group climate characteristics.
Steimer, Andreas; Schindler, Kaspar
2015-01-01
Oscillations between high and low values of the membrane potential (UP and DOWN states respectively) are an ubiquitous feature of cortical neurons during slow wave sleep and anesthesia. Nevertheless, a surprisingly small number of quantitative studies have been conducted only that deal with this phenomenon's implications for computation. Here we present a novel theory that explains on a detailed mathematical level the computational benefits of UP states. The theory is based on random sampling by means of interspike intervals (ISIs) of the exponential integrate and fire (EIF) model neuron, such that each spike is considered a sample, whose analog value corresponds to the spike's preceding ISI. As we show, the EIF's exponential sodium current, that kicks in when balancing a noisy membrane potential around values close to the firing threshold, leads to a particularly simple, approximative relationship between the neuron's ISI distribution and input current. Approximation quality depends on the frequency spectrum of the current and is improved upon increasing the voltage baseline towards threshold. Thus, the conceptually simpler leaky integrate and fire neuron that is missing such an additional current boost performs consistently worse than the EIF and does not improve when voltage baseline is increased. For the EIF in contrast, the presented mechanism is particularly effective in the high-conductance regime, which is a hallmark feature of UP-states. Our theoretical results are confirmed by accompanying simulations, which were conducted for input currents of varying spectral composition. Moreover, we provide analytical estimations of the range of ISI distributions the EIF neuron can sample from at a given approximation level. Such samples may be considered by any algorithmic procedure that is based on random sampling, such as Markov Chain Monte Carlo or message-passing methods. Finally, we explain how spike-based random sampling relates to existing computational
NASA Astrophysics Data System (ADS)
Ruelas-Mayorga, A.; Sánchez, L. J.; Trujillo-Lara, M.; Nigoche-Netro, A.; Echevarría, J.; García, A. M.; Ramírez-Vélez, J.
2016-10-01
In this paper we carry out a preliminary study of the dependence of the Tully-Fisher Relation (TFR) with the width and intensity level of the absolute magnitude interval of a limited sample of 2411 galaxies taken from Mathewson and Ford (Astrophys. J. Suppl. Ser. 107:97, 1996). The galaxies in this sample do not differ significantly in morphological type, and are distributed over an ˜ 11-magnitude interval (-24.4 < I < -13.0). We take as directives the papers by Nigoche-Netro et al. (Astron. Astrophys. 491:731, 2008; Mon. Not. R. Astron. Soc. 392:1060, 2009; Astron. Astrophys. 516:96, 2010) in which they study the dependence of the Kormendy (KR), the Fundamental Plane (FPR) and the Faber-Jackson Relations (FJR) with the magnitude interval within which the observed galaxies used to derive these relations are contained. We were able to characterise the behaviour of the TFR coefficients (α, β ) with respect to the width of the magnitude interval as well as with the brightness of the galaxies within this magnitude interval. We concluded that the TFR for this specific sample of galaxies depends on observational biases caused by arbitrary magnitude cuts, which in turn depend on the width and intensity of the chosen brightness levels.
Matzke, Melissa M; Allan, Sarah E; Anderson, Kim A; Waters, Katrina M
2012-12-01
The use of passive sampling devices (PSDs) for monitoring hydrophobic organic contaminants in aquatic environments can entail logistical constraints that often limit a comprehensive statistical sampling plan, thus resulting in a restricted number of samples. The present study demonstrates an approach for using the results of a pilot study designed to estimate sampling variability, which in turn can be used as variance estimates for confidence intervals for future n = 1 PSD samples of the same aquatic system. Sets of three to five PSDs were deployed in the Portland Harbor Superfund site for three sampling periods over the course of two years. The PSD filters were extracted and, as a composite sample, analyzed for 33 polycyclic aromatic hydrocarbon compounds. The between-sample and within-sample variances were calculated to characterize sources of variability in the environment and sampling methodology. A method for calculating a statistically reliable and defensible confidence interval for the mean of a single aquatic passive sampler observation (i.e., n = 1) using an estimate of sample variance derived from a pilot study is presented. Coverage probabilities are explored over a range of variance values using a Monte Carlo simulation.
Which are the best VO2 sampling intervals to characterize low to severe swimming intensities?
de Jesus, K; Guidetti, L; de Jesus, K; Vilas-Boas, J P; Baldari, C; Fernandes, R J
2014-11-01
Cardiorespiratory response in swimming has been used to better understand aerobic performance, especially by assessing oxygen uptake (VO2). The current study aimed to compare different VO2 time-averaging intervals throughout low to severe swimming intensities, hypothesizing that VO2 values are similar for different time averages at low to moderate and heavy swimming intensities, but not for the severe domain. 20 male trained swimmers completed an incremental protocol of 7×200 m until exhaustion (0.05 m/s increments and 30 s intervals). VO2 was measured by a portable gas analyser connected to a snorkel system. 6 time average intervals (breath-by-breath, 5, 10, 15, 20 and 30 s) were compared for all the protocol steps. Breath-by-breath and 5 s average exhibited higher VO2 values than averages≥10 s for all swimming intensities (P≤0.02; partial η(2)≤0.28). VO2 values did not differ between 10, 15, 20 and 30 s averages throughout the incremental protocol (P>0.05; partial η(2)≤0.05). Furthermore, 10 and 15 s averages showed the lowest VO2 mean difference (0.19 mL( · )kg(-1 · )min(-1)). For the 6 time average intervals analysed, 10 and 15 s averages were those that showed the lowest changes on VO2 values. We recommended the use of 10 and 15 s time averaging intervals to determine relevant respiratory gas exchange parameters along a large spectrum of swimming intensities. © Georg Thieme Verlag KG Stuttgart · New York.
Optical effects module and passive sample array
NASA Technical Reports Server (NTRS)
Linton, R. C.
1983-01-01
The Optical Effects Module (OEM) has the objective to monitor the effects of the deposition and adhesion of both molecular species and particles on optical surfaces in the Shuttle cargo bay environment. The OEM performs inflight measurements of the ultraviolet (253.7 nm) transmittance and diffuse reflectance of five optical samples at regular intervals throughout the orbital mission. Most of the obtained results indicates or implies the absence of a significant accumulation of contamination other than particulates on the samples. The contaminant species (or particulates) adhering to the samples of the Passive Sample Array (PSA) were identified by means of Auger and X-ray energy dispersive analyses. The elements silicon, chlorine, and phosphorus were discovered.
This presentation, On-Line Tools for Proper Vertical Positioning of Sampling Intervals During Site Assessment, describes an approach to locating monitoring wells that is based on application of ground water models. The ideal use of both the model and site assessment funds is to ...
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.
2008-01-01
Applications of distribution theory for the squared multiple correlation coefficient and the squared cross-validation coefficient are reviewed, and computer programs for these applications are made available. The applications include confidence intervals, hypothesis testing, and sample size selection. (Contains 2 tables.)
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.
2008-01-01
Applications of distribution theory for the squared multiple correlation coefficient and the squared cross-validation coefficient are reviewed, and computer programs for these applications are made available. The applications include confidence intervals, hypothesis testing, and sample size selection. (Contains 2 tables.)
Thomson, Amara C; Ramos, Joyce S; Fassett, Robert G; Coombes, Jeff S; Dalleck, Lance C
2015-01-01
This study sought to determine the optimal criteria and sampling interval to detect a V̇O2 plateau at V̇O2max in patients with metabolic syndrome. Twenty-three participants with criteria-defined metabolic syndrome underwent a maximal graded exercise test. Four different sampling intervals and three different V̇O2 plateau criteria were analysed to determine the effect of each parameter on the incidence of V̇O2 plateau at V̇O2max. Seventeen tests were classified as maximal based on attainment of at least two out of three criteria. There was a significant (p < 0.05) effect of 15-breath (b) sampling interval on the incidence of V̇O2 plateau at V̇O2max across the ≤ 50 and ≤ 80 mL ∙ min(-1) conditions. Strength of association was established by the Cramer's V statistic (φc); (≤ 50 mL ∙ min(-1) [φc = 0.592, p < 0.05], ≤ 80 mL ∙ min(-1) [φc = 0.383, p < 0.05], ≤ 150 mL ∙ min(-1) [φc = 0.246, p > 0.05]). When conducting maximal stress tests on patients with metabolic syndrome, a 15-b sampling interval and ≤ 50 mL ∙ min(-1) criteria should be implemented to increase the likelihood of detecting V̇O2 plateau at V̇O2max.
ERIC Educational Resources Information Center
Pinto, Carlos; Machado, Armando
2011-01-01
To better understand short-term memory for temporal intervals, we re-examined the choose-short effect. In Experiment 1, to contrast the predictions of two models of this effect, the subjective shortening and the coding models, pigeons were exposed to a delayed matching-to-sample task with three sample durations (2, 6 and 18 s) and retention…
ERIC Educational Resources Information Center
Pinto, Carlos; Machado, Armando
2011-01-01
To better understand short-term memory for temporal intervals, we re-examined the choose-short effect. In Experiment 1, to contrast the predictions of two models of this effect, the subjective shortening and the coding models, pigeons were exposed to a delayed matching-to-sample task with three sample durations (2, 6 and 18 s) and retention…
An Introduction to Confidence Intervals for Both Statistical Estimates and Effect Sizes.
ERIC Educational Resources Information Center
Capraro, Mary Margaret
This paper summarizes methods of estimating confidence intervals, including classical intervals and intervals for effect sizes. The recent American Psychological Association (APA) Task Force on Statistical Inference report suggested that confidence intervals should always be reported, and the fifth edition of the APA "Publication Manual"…
Effect of resting interval for muscle regeneration in mice.
Sasaki, Aizawa; Aizawa, Toshimi; Tomiya, Akihito; Matsubara, Yoshihiro; Kokubun, Shoichi; Itoi, Eiji
2007-01-01
Muscle tissue has an exceptional ability to regenerate, however, unresting damage to the muscles by intense and frequent exercises occasionally causes prolonged muscle fatigue, soreness, and underperformance in sports. Taking rest is generally considered to be crucial for regular training to avoid the accumulation of muscle damage. We hypothesized that differences in the resting intervals between two periods of exercise may result in histological differences in muscle regeneration. An eccentric contraction model of mouse gastrocnemius muscle was made using percutaneus electrical stimulation. The mice received eccentric exercises twice with resting intervals of 0, 12, 24 hours, 2, and 3 days. The authors investigated the ratio of myofibers with central nuclei to whole myofibers histologically (the centronuclear cell ratio; CNCR) at 14 days after the second exercise as an index of the muscle regeneration. The CNCR of the group that exercised one-time was 29.5%. In the groups exercised twice, it increased from 31.8% with an interval of 0 hours to a peak of 43.9% with 24 hours, then decreased to 32.8% with an interval of 3 days. The ratios of the groups with intervals of 12 and 24 hours were higher than those with one-time exercise and those with the intervals of 0 hours, 2 days, and 3 days. The resting interval between two periods of eccentric exercises affected the histology of muscle regeneration. The amount of muscle damage and/or the recovery process of damaged muscles should vary depending on the length of resting interval between strenuous exercises. An appropriate interval for rest must be necessary in order to avoid further muscle damage.
Steimer, Andreas; Schindler, Kaspar
2015-01-01
Oscillations between high and low values of the membrane potential (UP and DOWN states respectively) are an ubiquitous feature of cortical neurons during slow wave sleep and anesthesia. Nevertheless, a surprisingly small number of quantitative studies have been conducted only that deal with this phenomenon’s implications for computation. Here we present a novel theory that explains on a detailed mathematical level the computational benefits of UP states. The theory is based on random sampling by means of interspike intervals (ISIs) of the exponential integrate and fire (EIF) model neuron, such that each spike is considered a sample, whose analog value corresponds to the spike’s preceding ISI. As we show, the EIF’s exponential sodium current, that kicks in when balancing a noisy membrane potential around values close to the firing threshold, leads to a particularly simple, approximative relationship between the neuron’s ISI distribution and input current. Approximation quality depends on the frequency spectrum of the current and is improved upon increasing the voltage baseline towards threshold. Thus, the conceptually simpler leaky integrate and fire neuron that is missing such an additional current boost performs consistently worse than the EIF and does not improve when voltage baseline is increased. For the EIF in contrast, the presented mechanism is particularly effective in the high-conductance regime, which is a hallmark feature of UP-states. Our theoretical results are confirmed by accompanying simulations, which were conducted for input currents of varying spectral composition. Moreover, we provide analytical estimations of the range of ISI distributions the EIF neuron can sample from at a given approximation level. Such samples may be considered by any algorithmic procedure that is based on random sampling, such as Markov Chain Monte Carlo or message-passing methods. Finally, we explain how spike-based random sampling relates to existing
Pointwise confidence intervals for a survival distribution with small samples or heavy censoring.
Fay, Michael P; Brittain, Erica H; Proschan, Michael A
2013-09-01
We propose a beta product confidence procedure (BPCP) that is a non-parametric confidence procedure for the survival curve at a fixed time for right-censored data assuming independent censoring. In such situations, the Kaplan-Meier estimator is typically used with an asymptotic confidence interval (CI) that can have coverage problems when the number of observed failures is not large, and/or when testing the latter parts of the curve where there are few remaining subjects at risk. The BPCP guarantees central coverage (i.e. ensures that both one-sided error rates are no more than half of the total nominal rate) when there is no censoring (in which case it reduces to the Clopper-Pearson interval) or when there is progressive type II censoring (i.e. when censoring only occurs immediately after failures on fixed proportions of the remaining individuals). For general independent censoring, simulations show that the BPCP maintains central coverage in many situations where competing methods can have very substantial error rate inflation for the lower limit. The BPCP gives asymptotically correct coverage and is asymptotically equivalent to the CI on the Kaplan-Meier estimator using Greenwood's variance. The BPCP may be inverted to create confidence procedures for a quantile of the underlying survival distribution. Because the BPCP is easy to implement, offers protection in settings when other methods fail, and essentially matches other methods when they succeed, it should be the method of choice.
Anxiolytic-like effects of leptin on fixed interval responding.
Tyree, Susan M; Munn, Robert G K; McNaughton, Neil
2016-09-01
Leptin has been shown to affect energy homeostasis, learning and memory, and some models of anxiolytic action. However, leptin has produced inconsistent results in previous non-operant behavioural tests of anxiety. Here, we test the anxiolytic potential of leptin in an operant paradigm that has produced positive results across all classes of anxiolytic so far tested. Rats were tested in the Fixed Interval 60 Seconds (FI60) task following administration of 0/0.5/1.0mg/kg (i.p.) leptin or an active anxiolytic control of 5mg/kg (i.p.) chlordiazepoxide (CDP). By the end of the 14days of testing in the FI60 task, 0.5mg/kg leptin released suppressed responding in a manner similar to CDP, and 1.0mg/kg leptin produced a relative depression in responding, a similar outcome pattern to previously tested 5HT-agonist anxiolytics. This suggests that leptin behaves similarly to established serotonergic anxiolytics such as buspirone and fluoxetine; with the delay in development of effect during testing, and the inverted-U dose-response curve explaining the inconsistent behaviour of leptin in behavioural tests of anxiety, as this type of pattern is common to serotonergic anxiolytics. Copyright © 2016 Elsevier Inc. All rights reserved.
Central tendency effects in time interval reproduction in autism
Karaminis, Themelis; Cicchini, Guido Marco; Neil, Louise; Cappagli, Giulia; Aagten-Murphy, David; Burr, David; Pellicano, Elizabeth
2016-01-01
Central tendency, the tendency of judgements of quantities (lengths, durations etc.) to gravitate towards their mean, is one of the most robust perceptual effects. A Bayesian account has recently suggested that central tendency reflects the integration of noisy sensory estimates with prior knowledge representations of a mean stimulus, serving to improve performance. The process is flexible, so prior knowledge is weighted more heavily when sensory estimates are imprecise, requiring more integration to reduce noise. In this study we measure central tendency in autism to evaluate a recent theoretical hypothesis suggesting that autistic perception relies less on prior knowledge representations than typical perception. If true, autistic children should show reduced central tendency than theoretically predicted from their temporal resolution. We tested autistic and age- and ability-matched typical children in two child-friendly tasks: (1) a time interval reproduction task, measuring central tendency in the temporal domain; and (2) a time discrimination task, assessing temporal resolution. Central tendency reduced with age in typical development, while temporal resolution improved. Autistic children performed far worse in temporal discrimination than the matched controls. Computational simulations suggested that central tendency was much less in autistic children than predicted by theoretical modelling, given their poor temporal resolution. PMID:27349722
Saha, Krishna K
2012-12-20
The intraclass correlation in binary outcome data sampled from clusters is an important and versatile measure in many biological and biomedical investigations. Properties of the different estimators of the intraclass correlation based on the parametric, semi-parametric, and nonparametric approaches have been studied extensively, mainly in terms of bias and efficiency [see, for example, Ridout et al., Biometrics 1999, 55:137-148; Paul et al., Journal of Statistical Computation and Simulation 2003, 73:507-523; and Lee, Statistical Modelling 2004, 4: 113-126], but little attention has been paid to extending these results to the problem of the confidence intervals. In this article, we generalize the results of the four point estimators by constructing asymptotic confidence intervals obtaining closed-form asymptotic and sandwich variance expressions of those four point estimators. It appears from simulation results that the asymptotic confidence intervals based on these four estimators have serious under-coverage. To remedy this, we introduce the Fisher's z-transformation approach on the intraclass correlation coefficient, the profile likelihood approach based on the beta-binomial model, and the hybrid profile variance approach based on the quadratic estimating equation for constructing the confidence intervals of the intraclass correlation for binary outcome data. As assessed by Monte Carlo simulations, these confidence interval approaches show significant improvement in the coverage probabilities. Moreover, the profile likelihood approach performs quite well by providing coverage levels close to nominal over a wide range of parameter combinations. We provide applications to biological data to illustrate the methods.
Effect of acute interval sprinting exercise on postprandial lipemia of sedentary young men
Chu, Aaron; Boutcher, Yati N; Boutcher, Stephen H
2016-01-01
[Purpose] Postprandial lipemia (PPL) contributesto the development of atherosclerosis. In females, repeated 8-second bouts of interval sprinting exercise reduced PPL, however, the effect of 8-second bouts of interval sprinting on PPL of overweight males is undetermined. Thus, the effect of 8-secondsof interval sprinting for 20 min, the night before ingestion of a high-fat meal (HFM), on plasma triacylglycerol(TG) levelswas examined. [Methods] Ten overweight males acted as participants (BMI = 26±3.0kg/m2, age 22 ± 2.5 years). A crossover design was employed withinterval sprinting and a noexercise condition separated by 7days. Participants consumed a milkshake (high-fat meal;HFM = 4170 kJ/993 Kcal) the morning after an overnight fast, followed by 4 hourly blood samples. Participants performedone bout of interval sprinting (8seconds sprinting at 110-115rpm, 12seconds active recovery at ~60rpm for 20 minutes) the evening before the consumption of the HFM. [Results] Postprandial TG was 22.5% lower in the interval sprinting compared to the noexercise condition when comparing the change in total area under the curve (ΔAUCT): ISE(7.15±1.90mmolL-1h-1) versus noexercise (9.22±3.44mmolL-1h-1), p=.014. The correlation between fasting TG levels in the noexercise condition and total reduction in AUCT between the conditions was significant (r=.87, p=.001). [Conclusion] One 20-min bout of interval sprinting,the night before consumption of a HFM,significantly attenuated the PPL response of sedentary males. PMID:27298807
Viaño-Santasmarinas, Jorge; Rey, Ezequiel; Carballeira, Sergio; Padrón-Cabo, Alexis
2017-02-08
The purpose of this study was to compare the effects of 2 high-intensity interval training protocols (HIIT) with different interval durations (short (SI) vs long (LI)), based on peak running velocity in 30-15 Intermittent Fitness Test (VIFT) in handball players. Eighteen highly trained players (age: 22.7±3.9 years; height: 181.5±6.6 cm; body mass: 84.7±14.1 kg) were randomly assigned to SI (2 sets of 22 intervals of 10-s runs at 95%VIFT) or LI (5 sets of 3 min intervals at 85% VIFT) group. The intervention program had to be carried out 2 times a week over 6 weeks. Before and after training period, 10 m sprint, countermovement jump, repeated sprint ability (RSA) and 30- 15IFT were assessed. In the within-group analysis, significant improvements in VIFT were found in SI (8.18%) and LI (8.19%) from pre-test to post-test. Players in both SI and LI also showed significant enhancements in RSA average time (Effect Size (ES)= 0.72 and 0.38, respectively), total time (ES= 0.72 and 0.38, respectively), and percentage of decrement (ES= 1.08 and 0.77, respectively) from pre-test to post-test. Percentage changes in VIFT, for both groups combined, had a very large correlation with percentage changes in percentage of decrement of RSA (r= 0.857). In the between-groups, there were no differences between the training groups (SI and LI) in any variable (p>0.05). These results indicate that both HIIT protocols are effective for fitness development during pre-season period in handball players. However, SI should be considered as preferred HIIT method due to its higher specificity.
A Further Assessment of Momentary Time-Sampling across Extended Interval Lengths
ERIC Educational Resources Information Center
Alvero, Alicia M.; Rappaport, Eva; Taylor, Matthew A.
2011-01-01
The current study compared the estimation of momentary time-sampling (MTS) to actual safety performance of three ergonomic responses: back, shoulder, and feet. Actual safety performance was established for the five participants by measuring the target responses with a continuous procedure. MTS 90, 105, 120, 135, 150, 165, 180, 195, 210, 240, and…
A Further Assessment of Momentary Time-Sampling across Extended Interval Lengths
ERIC Educational Resources Information Center
Alvero, Alicia M.; Rappaport, Eva; Taylor, Matthew A.
2011-01-01
The current study compared the estimation of momentary time-sampling (MTS) to actual safety performance of three ergonomic responses: back, shoulder, and feet. Actual safety performance was established for the five participants by measuring the target responses with a continuous procedure. MTS 90, 105, 120, 135, 150, 165, 180, 195, 210, 240, and…
Kowalik, S; Kedzierski, W
2011-01-01
The effect of interval vs. continuous exercise on plasma leptin and ghrelin concentration in young Standardbred horses was studied. The experiment was conducted on 27 trotters, in the age between 2 and 3 years. They were divided into two groups according to the type of exercise. Blood samples were collected through jugular venipuncture in the following experimental conditions: at rest, immediately after exercise and 30 minutes after the end of the effort. Plasma leptin and ghrelin concentrations were determined using RIA tests. The continuous exercise induced an increase in plasma leptin concentration whereas the interval type of exercise did not influence the level of this hormone (3.47 +/- 0.78 vs. 4.07 +/- 0.94 and 2.31 +/- 0.15 vs. 2.36 +/- 0.21 ng/mL, respectively). The plasma ghrelin concentration measured after the continuous exercise, significantly increased (720 +/- 27.4 vs. 814 +/- 13.8; p < or = 0.05) whereas concentration of this hormone assessed after the interval exercise, significantly dropped (982 +/- 56.5 vs. 842 +/- 35.6 pg/mL; p < or = 0.05). The changes in plasma ghrelin concentration measured after the end of the effort correlated inversely with blood lactic acid concentration. In conclusion, the obtained results showed that medium-intensive type of exercise, such as trot, interval or continuous, slightly affected plasma leptin level but significantly affected plasma ghrelin concentration in young Standardbred trotters.
Dakhel, Yaman; Jamali, Fakhreddin . E-mail: fjamali@ualberta.ca
2006-07-01
Calcium channel blockers and macrolide antibiotics account for many drug interactions. Anecdotal reports suggest interactions between the two resulting in severe side effects. We studied the interaction between verapamil and erythromycin in the rat to see whether it occurs at the pharmacokinetics or pharmacodynamic level. Adult male Sprague-Dawley rats received doses of 1 mg/kg verapamil or 100 mg/kg erythromycin alone or in combination (n = 6/group). Serial blood samples (0-6 h) were taken for determination of the drug concentrations using HPLC. Electrocardiograms were recorded (0-6 h) through subcutaneously inserted lead II. Binding of the drugs to plasma proteins was studied using spiked plasma. Verapamil prolonged PR but not QT interval. Erythromycin prolonged QT but not PR interval. The combination resulted in a significant increase in PR interval prolongation and AV node blocks but did not further prolong QT interval. Pharmacokinetics and protein binding of neither drug were altered by the other. Our rat data confirm the anecdotal human case reports that combination of erythromycin and verapamil can result in potentiation of the cardiovascular response. The interaction appears to be at the pharmacodynamic rather than pharmacokinetic level hence may be extrapolated to other calcium channel antagonists.
Xie, Bin; Yan, Xianfeng
2017-01-01
Purpose. The aim of this study was to compare the effects of high-intensity interval training (INTERVAL) and moderate-intensity continuous training (CONTINUOUS) on aerobic capacity in cardiac patients. Methods. A meta-analysis identified by searching the PubMed, Cochrane Library, EMBASE, and Web of Science databases from inception through December 2016 compared the effects of INTERVAL and CONTINUOUS among cardiac patients. Results. Twenty-one studies involving 736 participants with cardiac diseases were included. Compared with CONTINUOUS, INTERVAL was associated with greater improvement in peak VO2 (mean difference 1.76 mL/kg/min, 95% confidence interval 1.06 to 2.46 mL/kg/min, p < 0.001) and VO2 at AT (mean difference 0.90 mL/kg/min, 95% confidence interval 0.0 to 1.72 mL/kg/min, p = 0.03). No significant difference between the INTERVAL and CONTINUOUS groups was observed in terms of peak heart rate, peak minute ventilation, VE/VCO2 slope and respiratory exchange ratio, body mass, systolic or diastolic blood pressure, triglyceride or low- or high-density lipoprotein cholesterol level, flow-mediated dilation, or left ventricular ejection fraction. Conclusions. This study showed that INTERVAL improves aerobic capacity more effectively than does CONTINUOUS in cardiac patients. Further studies with larger samples are needed to confirm our observations. PMID:28386556
Jakobsen, Ida; Solomon, Thomas P. J.
2016-01-01
Interval-type exercise is effective for improving glycemic control, but the optimal approach is unknown. The purpose of this study was to determine the importance of the interval length on changes in postprandial glycemic control following a single exercise bout. Twelve subjects with type 2 diabetes completed a cross-over study with three 1-hour interventions performed in a non-randomized but counter-balanced order: 1) Interval walking consisting of repeated cycles of 3 min slow (aiming for 54% of Peak oxygen consumption rate [VO2peak]) and 3 min fast (aiming for 89% of VO2peak) walking (IW3); 2) Interval walking consisting of repeated cycles of 1 min slow and 1 min fast walking (IW1) and 3) No walking (CON). The exercise interventions were matched with regards to walking speed, and VO2 and heart rate was assessed throughout all interventions. A 4-hour liquid mixed meal tolerance test commenced 30 min after each intervention, with blood samples taken regularly. IW3 and IW1 resulted in comparable mean VO2 and heart rates. Overall mean postprandial blood glucose levels were lower after IW3 compared to CON (10.3±3.0 vs. 11.1±3.3 mmol/L; P < 0.05), with no significant differences between IW1 (10.5±2.8 mmol/L) and CON or IW3 and IW1 (P > 0.05 for both). Conversely blood glucose levels at specific time points during the MMTT differed significantly following both IW3 and IW1 as compared to CON. Our findings support the previously found blood glucose lowering effect of IW3 and suggest that reducing the interval length, while keeping the walking speed and time spend on fast and slow walking constant, does not result in additional improvements. Trial Registration ClinicalTrials.gov NCT02257190 PMID:27695119
Age effects in discrimination of intervals within rhythmic tone sequences
Fitzgibbons, Peter J.; Gordon-Salant, Sandra
2015-01-01
This study measured listener sensitivity to increments of a target inter-onset interval (IOI) embedded within tone sequences that featured different rhythmic patterns. The sequences consisted of six 50-ms 1000-Hz tone bursts separated by silent intervals that were adjusted to create different timing patterns. Control sequences were isochronous, with all tonal IOIs fixed at either 200 or 400 ms, while other patterns featured combinations of the two IOIs arranged to create different sequential tonal groupings. Duration difference limens in milliseconds for increments of a single sequence IOI were measured adaptively by adjusting the duration of an inter-tone silent interval. Specific target IOIs within sequences differed across discrimination conditions. Listeners included younger normal-hearing adults and groups of older adults with and without hearing loss. Discrimination performance measured for each of the older groups of listeners was observed to be equivalent, with each group exhibiting significantly poorer discrimination performance than the younger listeners in each sequence condition. Additionally, the specific influence of variable rhythmic grouping on temporal sensitivity was found to be greatest among older listeners. PMID:25618068
NASA Astrophysics Data System (ADS)
Tada, A.; Tanakamaru, H.
2008-12-01
Total mass flux (load) from a catchment is a basic factor in evaluating chemical weathering or in TMDLs implementation. So far, many combinations of load estimation methods with sampling strategies were tested to obtain an unbiased flux estimate. To utilize such flux estimates in the political or scientific application, the information of uncertainty of flux estimates should also be provided. Giving the interval estimate of total flux may be a desirable solution to this situation. Total solute flux from a small, undisturbed forested catchment (12.8ha) during 10 months were calculated based on high-temporal resolution data and used in validation of 95% confidence intervals (CIs) of flux estimates. Water quality data (sodium, potassium, and chloride concentration) were collected and measured every 15 minutes during 10 months in 2004 by the on-site monitoring system using FIP (flow injection potentiometry) method with ion-selective electrodes. Water quantity data (the flow rate data) were measured continuously by V-notch weir at the catchment outlet. Flux estimates and 95% CIs were calculated for three indices with 41 methods; sample average, flow- weighted average, the Beale ratio estimator, rating curve method with simple linear regression between flux and the flow rate, and nine regression models in the USGS Load Estimator (Loadest). Smearing estimates, MVUE estimates, and estimates by composite method were also evaluated concerning nine regression models in Load Estimator. Two sampling strategies were tested; periodical sampling (daily and weekly) and flow stratified sampling. After data were sorted in ascending order of the flow rate, five strata were configured so that each stratum contained same number of data in flow stratified sampling. The performance of these 95% CIs was evaluated by the rate of inclusion of true flux value within these CIs, which should be expected as 0.95. A simple bootstrap method was adopted to construct the CIs with 2,000 bootstrap
Felding, P; Rustad, P; Mårtensson, A; Kairisto, V; Franzson, L; Hyltoft Petersen, P; Uldall, A
2004-01-01
The rules for recruitment of reference individuals, inclusion and preparation of individuals, blood collection, treatment of samples (and control materials) and analysis at the 102 medical laboratories attending the Nordic Reference Interval Project (NORIP) are given as well as the rules for central exclusion of reference individuals. The individuals (18-91-year-olds) should be evenly distributed on age and gender groups. The 3002 reference individuals who contributed at least one reference value to the finally suggested reference intervals were characterized using the information in the questionnaire. Gender, age and country are the main entries in the tables. Other variables in the cross-tables or figure are height, weight, body mass index, ethnic origin, heredity for diabetes, chronic disease, oestrogens or oral contraceptives, other medication, hard physical activity, previous blood donations, smoking habits, use of alcohol, hours since last meal and time of blood collection (hour, day of week, month, year). The Danes had the highest alcohol consumption and the Icelanders had the highest body mass index. The information in this article may interest potential users of the Nordic Reference Interval Project bio-bank and database (NOBIDA) in which serum, Li-heparin plasma and EDTA buffy coat from the mentioned individuals are stored below -80 degrees C.
Hematologic reference intervals and age effect in European Strigiformes.
Agusti Montolio, Susana; Molina López, Rafael; Cray, Carolyn; Lavín González, Santiago; Nicolás Francisco, Olga; Marco Sánchez, Ignasi; Casas-Díaz, Encarna; Cuenca Valera, Rafaela
2017-09-01
The clinical importance of hematologic testing in avian veterinary medicine is reflected in the increasing number of studies for the establishment of hematologic RIs of Strigiformes and other species. Age is an important physiologic factor in birds and the effect on hematology variable should be understood. The objective of this study was to determine baseline data of hematologic variables in 5 species of Iberian Strigiformes in different age classes. Nocturnal birds of prey were sampled at Wildlife Health Centers. Packed cell volume was determined by the microhematocrit centrifugation method, and RBC and WBC counts were determined using the direct hemocytometer count method with Natt and Herrick solution. Hemoglobin concentration was measured spectrophotometrically. The MCV, MCHC, and MHC were calculated using the standard formulas. The differential WBC count was performed by the routine microscopic evaluation of 200 cells on a blood smear manually stained with Wright stain. Thrombocyte blood count estimate was obtained from the blood film. No differences were observed between juveniles and adults for any variable evaluated in Tawny owl, Little owl, Scops owl, Long-eared owl, and Barn owl. In addition, PCV, RBC, and HGB of chicks were statistically significantly lower than in juveniles and adults, and total WBC was significantly higher in Tawny owl, Little owl, Scops owl, and Long-eared owl. Our findings provide evidence that laboratory data from chicks of Strigiformes are different compared to juveniles and adults; therefore, separate RIs were defined. © 2017 American Society for Veterinary Clinical Pathology.
Baek, Hyun Jae; Shin, JaeWook
2017-08-15
Most of the wrist-worn devices on the market provide a continuous heart rate measurement function using photoplethysmography, but have not yet provided a function to measure the continuous heart rate variability (HRV) using beat-to-beat pulse interval. The reason for such is the difficulty of measuring a continuous pulse interval during movement using a wearable device because of the nature of photoplethysmography, which is susceptible to motion noise. This study investigated the effect of missing heart beat interval data on the HRV analysis in cases where pulse interval cannot be measured because of movement noise. First, we performed simulations by randomly removing data from the RR interval of the electrocardiogram measured from 39 subjects and observed the changes of the relative and normalized errors for the HRV parameters according to the total length of the missing heart beat interval data. Second, we measured the pulse interval from 20 subjects using a wrist-worn device for 24 h and observed the error value for the missing pulse interval data caused by the movement during actual daily life. The experimental results showed that mean NN and RMSSD were the most robust for the missing heart beat interval data among all the parameters in the time and frequency domains. Most of the pulse interval data could not be obtained during daily life. In other words, the sample number was too small for spectral analysis because of the long missing duration. Therefore, the frequency domain parameters often could not be calculated, except for the sleep state with little motion. The errors of the HRV parameters were proportional to the missing data duration in the presence of missing heart beat interval data. Based on the results of this study, the maximum missing duration for acceptable errors for each parameter is recommended for use when the HRV analysis is performed on a wrist-worn device.
Food and Insulin Effect on QT/QTC Interval of ECG
2014-08-19
Effects of Different Meals on the QT/QTc Interval; Insulin and Oral Hypoglycemic [Antidiabetic] Drugs Causing Adverse Effects in Therapeutic Use; C-Peptide Effects on the QT/QTc Interval; Moxifloxacin ECG Profile in Fed and Fasted State; Japanese vs. Caucasian TQT Comparison
Willruth, A M; Steinhard, J; Enzensberger, C; Axt-Fliedner, R; Gembruch, U; Doelle, A; Dimitriou, I; Fimmers, R; Bahlmann, F
2016-02-04
Purpose: To assess the time intervals of the cardiac cycle in healthy fetuses in the second and third trimester using color tissue Doppler imaging (cTDI) and to evaluate the influence of different sizes of sample gates on time interval values. Materials and Methods: Time intervals were measured from the cTDI-derived Doppler waveform using a small and large region of interest (ROI) in healthy fetuses. Results: 40 fetuses were included. The median gestational age at examination was 26 + 1 (range: 20 + 5 - 34 + 5) weeks. The median frame rate was 116/s (100 - 161/s) and the median heart rate 143 (range: 125 - 158) beats per minute (bpm). Using small and large ROIs, the second trimester right ventricular (RV) mean isovolumetric contraction times (ICTs) were 39.8 and 41.4 ms (p = 0.17), the mean ejection times (ETs) were 170.2 and 164.6 ms (p < 0.001), the mean isovolumetric relaxation times (IRTs) were 52.8 and 55.3 ms (p = 0.08), respectively. The left ventricular (LV) mean ICTs were 36.2 and 39.4 ms (p = 0.05), the mean ETs were 167.4 and 164.5 ms (p = 0.013), the mean IRTs were 53.9 and 57.1 ms (p = 0.05), respectively. The third trimester RV mean ICTs were 50.7 and 50.4 ms (p = 0.75), the mean ETs were 172.3 and 181.4 ms (p = 0.49), the mean IRTs were 50.2 and 54.6 ms (p = 0.03); the LV mean ICTs were 45.1 and 46.2 ms (p = 0.35), the mean ETs were 175.2 vs. 172.9 ms (p = 0.29), the mean IRTs were 47.1 and 50.0 ms (p = 0.01), respectively. Conclusion: Isovolumetric time intervals can be analyzed precisely and relatively independent of ROI size. In the near future, automatic time interval measurement using ultrasound systems will be feasible and the analysis of fetal myocardial function can become part of the clinical routine. © Georg Thieme Verlag KG Stuttgart · New York.
A Comparison of Methods for Estimating Confidence Intervals for Omega-Squared Effect Size
ERIC Educational Resources Information Center
Finch, W. Holmes; French, Brian F.
2012-01-01
Effect size use has been increasing in the past decade in many research areas. Confidence intervals associated with effect sizes are encouraged to be reported. Prior work has investigated the performance of confidence interval estimation with Cohen's d. This study extends this line of work to the analysis of variance case with more than two…
A Comparison of Methods for Estimating Confidence Intervals for Omega-Squared Effect Size
ERIC Educational Resources Information Center
Finch, W. Holmes; French, Brian F.
2012-01-01
Effect size use has been increasing in the past decade in many research areas. Confidence intervals associated with effect sizes are encouraged to be reported. Prior work has investigated the performance of confidence interval estimation with Cohen's d. This study extends this line of work to the analysis of variance case with more than two…
Alternatives to P value: confidence interval and effect size.
Lee, Dong Kyu
2016-12-01
The previous articles of the Statistical Round in the Korean Journal of Anesthesiology posed a strong enquiry on the issue of null hypothesis significance testing (NHST). P values lie at the core of NHST and are used to classify all treatments into two groups: "has a significant effect" or "does not have a significant effect." NHST is frequently criticized for its misinterpretation of relationships and limitations in assessing practical importance. It has now provoked criticism for its limited use in merely separating treatments that "have a significant effect" from others that do not. Effect sizes and CIs expand the approach to statistical thinking. These attractive estimates facilitate authors and readers to discriminate between a multitude of treatment effects. Through this article, I have illustrated the concept and estimating principles of effect sizes and CIs.
Alternatives to P value: confidence interval and effect size
2016-01-01
The previous articles of the Statistical Round in the Korean Journal of Anesthesiology posed a strong enquiry on the issue of null hypothesis significance testing (NHST). P values lie at the core of NHST and are used to classify all treatments into two groups: "has a significant effect" or "does not have a significant effect." NHST is frequently criticized for its misinterpretation of relationships and limitations in assessing practical importance. It has now provoked criticism for its limited use in merely separating treatments that "have a significant effect" from others that do not. Effect sizes and CIs expand the approach to statistical thinking. These attractive estimates facilitate authors and readers to discriminate between a multitude of treatment effects. Through this article, I have illustrated the concept and estimating principles of effect sizes and CIs. PMID:27924194
Ebach, Sarah C; Ramsthaler, Frank; Birngruber, Christoph G; Verhoff, Marcel A
2010-01-01
In the experiment, 16 human bones with known postmortem interval (PMI) that had been buried in soil (0.2 to about 2000 years) were tested in a blind setup with two established methods for determining the PMI (UV fluorescence of the surface of a fresh cut and the luminol chemiluminescence) and with two methods applied for this purpose for the first time (Hexagon OBTI test and Combur test). The results underline the importance of the UV fluorescence and luminol tests in determining the PMI, especially with regard to the question whether the PMI is forensically relevant or not. The results for both new methods, the Combur test strips and the Hexagon OBTI test, which were originally developed for the detection of hemoglobin, were negative for all samples. It remains to be seen if the negative results for these two methods may be due to an inability of hemoglobin or its metabolites to dissolve in the Tris buffer solution used in the experiment.
Badenes-Ribera, Laura; Frias-Navarro, Dolores; Pascual-Soler, Marcos; Monterde-I-Bort, Héctor
2016-11-01
The statistical reform movement and the American Psychological Association (APA) defend the use of estimators of the effect size and its confidence intervals, as well as the interpretation of the clinical significance of the findings. A survey was conducted in which academic psychologists were asked about their behavior in designing and carrying out their studies. The sample was composed of 472 participants (45.8% men). The mean number of years as a university professor was 13.56 years (SD= 9.27). The use of effect-size estimators is becoming generalized, as well as the consideration of meta-analytic studies. However, several inadequate practices still persist. A traditional model of methodological behavior based on statistical significance tests is maintained, based on the predominance of Cohen’s d and the unadjusted R2/η2, which are not immune to outliers or departure from normality and the violations of statistical assumptions, and the under-reporting of confidence intervals of effect-size statistics. The paper concludes with recommendations for improving statistical practice.
Assessing Mediational Models: Testing and Interval Estimation for Indirect Effects
ERIC Educational Resources Information Center
Biesanz, Jeremy C.; Falk, Carl F.; Savalei, Victoria
2010-01-01
Theoretical models specifying indirect or mediated effects are common in the social sciences. An indirect effect exists when an independent variable's influence on the dependent variable is mediated through an intervening variable. Classic approaches to assessing such mediational hypotheses (Baron & Kenny, 1986; Sobel, 1982) have in recent years…
Dubois, Nathalie; Hallet, Claude; Seidel, Laurence; Demaret, Isabelle; Luppens, David; Ansseau, Marc; Rozet, Eric; Albert, Adelin; Hubert, Philippe; Charlier, Corinne
2015-05-01
To develop a model for estimating the time delay between last heroin consumption and blood sampling in chronic drug users. Eleven patients, all heroin inhalers undergoing detoxification, were included in the study. Several plasma samples were collected during the detoxification procedure and analyzed for the heroin metabolites 6-acetylmorphine (6AM), morphine (MOR), morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G), according to a UHPLC/MSMS method. The general linear mixed model was applied to time-related concentrations and a pragmatic four-step delay estimation approach was proposed based on the simultaneous presence of metabolites in plasma. Validation of the model was carried out using the jackknife technique on the 11 patients, and on a group of 7 test patients. Quadratic equations were derived for all metabolites except 6AM. The interval delay estimation was 2-4 days when only M3G present in plasma, 1-2 days when M6G and M3G were both present, 0-1 day when MOR, M6G and M3G were present and <2 h for all metabolites present. The 'jackknife' correlation between declared and actual estimated delays was 0.90. The overall precision of the delay estimates was 8-9 h. The delay between last heroin consumption and blood sampling in chronic drug users can be satisfactorily predicted from plasma heroin metabolites.
Effect of assay measurement error on parameter estimation in concentration-QTc interval modeling.
Bonate, Peter L
2013-01-01
Linear mixed-effects models (LMEMs) of concentration-double-delta QTc intervals (QTc intervals corrected for placebo and baseline effects) assume that the concentration measurement error is negligible, which is an incorrect assumption. Previous studies have shown in linear models that independent variable error can attenuate the slope estimate with a corresponding increase in the intercept. Monte Carlo simulation was used to examine the impact of assay measurement error (AME) on the parameter estimates of an LMEM and nonlinear MEM (NMEM) concentration-ddQTc interval model from a 'typical' thorough QT study. For the LMEM, the type I error rate was unaffected by assay measurement error. Significant slope attenuation ( > 10%) occurred when the AME exceeded > 40% independent of the sample size. Increasing AME also decreased the between-subject variance of the slope, increased the residual variance, and had no effect on the between-subject variance of the intercept. For a typical analytical assay having an assay measurement error of less than 15%, the relative bias in the estimates of the model parameters and variance components was less than 15% in all cases. The NMEM appeared to be more robust to AME error as most parameters were unaffected by measurement error. Monte Carlo simulation was then used to determine whether the simulation-extrapolation method of parameter bias correction could be applied to cases of large AME in LMEMs. For analytical assays with large AME ( > 30%), the simulation-extrapolation method could correct biased model parameter estimates to near-unbiased levels.
Improvements in Interval Time Tracking and Effects on Reading Achievement
ERIC Educational Resources Information Center
Taub, Gordon E.; McGrew, Kevin S.; Keith, Timothy Z.
2007-01-01
This study examined the effect of improvements in timing/rhythmicity on students' reading achievement. 86 participants completed pre- and post-test measures of reading achievement (i.e., Woodcock-Johnson III, Comprehensive Test of Phonological Processing, Test of Word Reading Efficiency, and Test of Silent Word Reading Fluency). Students in the…
Howell, Peter; Staveley, Alison; Sackin, Stevie; Rustin, Lena
2007-01-01
Accurate methods for locating specific types of stuttering events are necessary for diagnosis, treatment and prognosis. A factor that could add variability to assessment of stuttering is noise on recordings. The effects of noise were assessed by adding noise to intervals of speech containing all fluent material, fluent material with a repetition or fluent material with a prolongation. These intervals allow a unique dysfluency response to be made. A statistical analysis of the occurrence of such intervals in spontaneous speech showed only a limited number of intervals met these criteria. This demonstrated that selecting intervals at random from spontaneous speech (as in Time Interval analysis procedure) will infrequently lead to a unique and unambiguous dysfluency specification for the interval. Intervals were selected for test from the intervals that met the stipulated criteria. These were presented for dysfluency judgement when the position of the stuttering within an interval was varied and with different amounts of added noise (no added noise, 3 dB and 6 dB of noise relative to mean speech amplitude). Accuracy in detecting stuttering type depended on noise level and the stuttering's position in the interval, both of which also depended on type of stuttering: Noise level affected detection of repetitions more than prolongations: Repetitions were more difficult to detect when they occurred at the end of an interval whereas prolongations were more difficult to detect when they were at the beginning of an interval. The findings underline the importance of adopting rigorous recording standards when speech is to be employed to make stuttering assessments. PMID:9857514
The effect of inter-set rest intervals on resistance exercise-induced muscle hypertrophy.
Henselmans, Menno; Schoenfeld, Brad J
2014-12-01
Due to a scarcity of longitudinal trials directly measuring changes in muscle girth, previous recommendations for inter-set rest intervals in resistance training programs designed to stimulate muscular hypertrophy were primarily based on the post-exercise endocrinological response and other mechanisms theoretically related to muscle growth. New research regarding the effects of inter-set rest interval manipulation on resistance training-induced muscular hypertrophy is reviewed here to evaluate current practices and provide directions for future research. Of the studies measuring long-term muscle hypertrophy in groups employing different rest intervals, none have found superior muscle growth in the shorter compared with the longer rest interval group and one study has found the opposite. Rest intervals less than 1 minute can result in acute increases in serum growth hormone levels and these rest intervals also decrease the serum testosterone to cortisol ratio. Long-term adaptations may abate the post-exercise endocrinological response and the relationship between the transient change in hormonal production and chronic muscular hypertrophy is highly contentious and appears to be weak. The relationship between the rest interval-mediated effect on immune system response, muscle damage, metabolic stress, or energy production capacity and muscle hypertrophy is still ambiguous and largely theoretical. In conclusion, the literature does not support the hypothesis that training for muscle hypertrophy requires shorter rest intervals than training for strength development or that predetermined rest intervals are preferable to auto-regulated rest periods in this regard.
The Effect of Temporal Intervals of Reinforcement upon Deductive and Inductive Generalizations.
ERIC Educational Resources Information Center
Crawford, Jack J.
Using verbal material, this study explored the effect of the temporal interval of feedback as it interacted with two other variables: (1) method of presenting learning material (inductive or deductive), and (2) activity of the learner during the delay interval (activity relevant or irrelevant to the material). The major objective was to compare…
Revisiting the Effect of Nicotine on Interval Timing
Daniels, Carter W.; Watterson, Elizabeth; Garcia, Raul; Mazur, Gabriel J.; Brackney, Ryan J.; Sanabria, Federico
2015-01-01
This paper reviews the evidence for nicotine-induced acceleration of the internal clock when timing in the seconds-to-minutes timescale, and proposes an alternative explanation to this evidence: that nicotine reduces the threshold for responses that result in more reinforcement. These two hypotheses were tested in male Wistar rats using a novel timing task. In this task, rats were trained to seek food at one location after 8 s since trial onset and at a different location after 16 s. Some rats received the same reward at both times (group SAME); some received a larger reward at 16 s (group DIFF). Steady baseline performance was followed by 3 days of subcutaneous nicotine administration (0.3 mg/kg), baseline recovery, and an antagonist challenge (mecamylamine, 1.0 mg/kg). Nicotine induced a larger, immediate reduction in latencies to switch (LTS) in group DIFF than in group SAME. This effect was sustained throughout nicotine administration. Mecamylamine administration and discontinuation of nicotine rapidly recovered baseline performance. These results support a response-threshold account of nicotinic disruption of timing performance, possibly mediated by nicotinic acetylcholine receptors. A detailed analysis of the distribution of LTSs suggests that anomalous effects of nicotine on LTS dispersion may be due to loss of temporal control of behavior. PMID:25637907
Feingold, Alan
2014-01-01
Objective Multilevel and latent growth models are frequently used interchangeably to examine differences between groups in trajectories of outcomes from controlled clinical trials. The unstandardized coefficient for the effect from group to slope (the treatment effect) from such models can be converted to a standardized mean difference (Cohen's d) between the treatment and control groups at end of study. This article addresses the confidence interval (CI) for this effect size. Method Two sets of equations for estimating the CI for the treatment effect size in multilevel models were derived and their usage was illustrated with data from the National Youth Study. Validity of the CIs was examined with a Monte Carlo simulation study that manipulated effect potency and sample size. Results The equivalence of the two new CI estimation methods was demonstrated and the Monte Carlo study found that bias in the CI for the effect size were not appreciably larger than bias in the CI for the widely used unstandardized coefficient. Conclusions Investigators reporting this increasingly popular effect size can estimate its CI with equations presented in this article. PMID:25181028
Psycho-Physical Effects of Varied Rest Intervals Following Warm-Up
ERIC Educational Resources Information Center
Aronchick, Joel; Burke, Edmund J.
1977-01-01
An assessment of the effects of rest intervals of varying lengths following a five minute warm-up revealed no significant differeence among them for perceived exertion, heart rate, and state anxiety. (MB)
Psycho-Physical Effects of Varied Rest Intervals Following Warm-Up
ERIC Educational Resources Information Center
Aronchick, Joel; Burke, Edmund J.
1977-01-01
An assessment of the effects of rest intervals of varying lengths following a five minute warm-up revealed no significant differeence among them for perceived exertion, heart rate, and state anxiety. (MB)
Effect of the rest interval duration between contractions on muscle fatigue
2012-01-01
Background We aimed to investigate the effect of rest interval, between successive contractions, on muscular fatigue. Methods Eighteen subjects performed elbow flexion and extension (30 repetitions) on an isokinetic dynamometer with 80º of range of motion. The flexion velocity was 120º/s, while for elbow extension we used 5 different velocities (30, 75, 120, 240, 360º/s), producing 5 different rest intervals (2.89, 1.28, 0.85, 0.57 and 0.54 s). Results We observed that when the rest interval was 2.89 s there was a reduction in fatigue. On the other hand, when the rest interval was 0.54 s the fatigue was increased. Conclusions When the resting time was lower (0.54 s) the decline of work in the flexor muscle group was higher compared with different rest interval duration. PMID:23181363
Effect of mood states on QT interval and QT dispersion in eating disorder patients.
Takimoto, Yoshiyuki; Yoshiuchi, Kazuhiro; Akabayashi, Akira
2008-04-01
Prolonged QT interval and QT dispersion have been reported in patients with eating disorders. Although the factors that cause prolongation remain unclear, mood states such as anxiety have been reported to influence QT interval and dispersion, probably via the autonomic nervous system. Therefore the aim of the present paper was to investigate mood effect on prolonged QT interval and QT dispersion. The subjects were 47 female anorexia nervosa (AN) and 48 female bulimia nervosa (BN) patients. In all of the patients, serum electrolyte levels were normal. QT interval and QT dispersion were measured from 12-lead electrocardiographic recordings. Mood states in each patient were measured using a Profile of Mood States (POMS) evaluation, and the patients were divided into high- and low-score groups for each POMS subscale. The differences in QT variables were compared between the two groups for each subscale. In the BN group, QT interval and QT dispersion in the high depression score group were significantly longer than those in the low depression score group, and QT dispersion was significantly greater in the high anxiety score group than in the low anxiety score group. In addition, QT interval and QT dispersion were significantly correlated with depression scores. In the AN group there were no significant differences in QT interval or QT dispersion between the high- and low-score groups for any POMS subscale. BN patients with worse states of depression or anxiety had longer QT intervals and larger QT dispersion. In BN patients, mood disturbance might increase the risk of arrhythmias.
ERIC Educational Resources Information Center
Kelley, Ken; Lai, Keke
2011-01-01
The root mean square error of approximation (RMSEA) is one of the most widely reported measures of misfit/fit in applications of structural equation modeling. When the RMSEA is of interest, so too should be the accompanying confidence interval. A narrow confidence interval reveals that the plausible parameter values are confined to a relatively…
ERIC Educational Resources Information Center
Kelley, Ken; Lai, Keke
2011-01-01
The root mean square error of approximation (RMSEA) is one of the most widely reported measures of misfit/fit in applications of structural equation modeling. When the RMSEA is of interest, so too should be the accompanying confidence interval. A narrow confidence interval reveals that the plausible parameter values are confined to a relatively…
Effects of three fluoroquinolones on QT interval in healthy adults after single doses.
Noel, Gary J; Natarajan, Jaya; Chien, Shuchean; Hunt, Thomas L; Goodman, Daniel B; Abels, Robert
2003-04-01
A clinical trial was conducted in healthy adult volunteers to assess the effect of levofloxacin, moxifloxacin, and ciprofloxacin on the QT and QTc interval. Electrocardiograms were recorded 24 hours before and after subjects took placebo, 1000 mg levofloxacin, 800 mg moxifloxacin, and 1500 mg ciprofloxacin in a double-blind, randomized, 4-period, 4-treatment, 4-sequence crossover trial. Changes in QT and QTc interval from baseline were assessed by several different methods. Increases in QT and QTc interval compared with placebo were consistently greater after moxifloxacin compared with either levofloxacin or ciprofloxacin. The mean postdose change from baseline QTc (Bazett) intervals for the 24-hour period after treatment with moxifloxacin ranged from 16.34 to 17.83 ms (P < .001, compared with placebo). For levofloxacin, this change ranged from 3.53 to 4.88 ms (P < .05, compared with placebo), and for ciprofloxacin, this change ranged from 2.27 to 4.93 ms (P < .05, compared with placebo, with the use of 3 of 5 baseline methods). A change in QTc (Bazett) interval from baseline can be demonstrated safely in healthy volunteers after single high doses of fluoroquinolones that achieve approximately 1.5 times the maximum plasma drug concentration that occurs after recommended doses. There is substantial daily variation in both QT and QTc interval, and the magnitude and frequency of changes in QTc interval can depend on the methods used. These factors need to be considered because clinical trials measuring the effects of drugs on QT intervals are used to estimate the risk of using these drugs. Greater changes in QT and QTc intervals after treatment with moxifloxacin compared with levofloxacin or ciprofloxacin are consistent with in vitro observations related to the effect of these drugs on rapid potassium (IK(r)) channels. The clinical relevance of these differences is not known.
Caffeine's effect on intermittent sprint cycling performance with different rest intervals.
Lee, Chia-Lun; Cheng, Ching-Feng; Lin, Jung-Charng; Huang, Hsin-Wei
2012-06-01
The purpose of this study was to investigate the effects of caffeine ingestion on the performance of an intermittent sprint cycling test (ISCT) with different rest intervals. Fourteen males with team sport experience consumed 6 mg kg(-1) of caffeine or a placebo 60 min prior to completing two sets of an ISCT with 4-min rest intervals. Each set consisted of 12 × 4-s sprints with 20- or 90-s active recovery intervals at 60-70 rpm. Blood lactate was collected at baseline and immediately following the completion of six sprints in each set. At 20-s recovery intervals, peak power and total work were not significantly different between conditions during the ISCT (P > 0.05); but caffeine reduced 6.31% effort for mean power in Sprint 10 of the later stage, as well as an increased fatigue index and elevated blood lactate levels during the ISCT (P < 0.05). At 90-s recovery intervals, peak power, mean power, and total work under caffeine conditions were significantly higher than under placebo conditions during the ISCT (P < 0.05), but no differences were apparent in fatigue index and blood lactate levels (P > 0.05). In conclusion, caffeine ingestion may be ergolytic, affecting performance and fatigue development in the later stage during a prolonged and intermittent sprint test with a short recovery interval. However, caffeine produces an ergogenic effect in the initial stage of an intermittent sprint performance with a longer recovery interval.
Hovanloo, Fariborz; Arefirad, Tahereh; Ahmadizad, Sajad
2013-05-31
Chronic and inflammatory diseases are major causes of mortality. Although the anti-inflammatory effects of exercise have been confirmed, but the effect of different types of exercise on inflammatory markers is different. The aim of this study is comparing the effects of two types of sprint interval (SIT) and continuous endurance (CET) training on inflammatory markers. Sixteen students who had recreational activities participated in this study and were randomly assigned to one of the two protocols. The SIT protocol consisted of four to six 30-s "all-out" Wingate tests separated by 4 minutes of recovery and The CET protocol included 90-120 minutes of cycling at 65% Vo2max. The two protocols were performed 3 days per week and for two weeks. In each group, two blood samples were collected before and 2 days (24 and 48 hrs) after the training. Results showed that there was no significant difference between the two training protocols on all measured parameters (p>0.05). The results of present study showed that the SIT and CET have identical effects on inflammatory markers.
The dose delivery effect of the different Beam ON interval in FFF SBRT: TrueBEAM
NASA Astrophysics Data System (ADS)
Tawonwong, T.; Suriyapee, S.; Oonsiri, S.; Sanghangthum, T.; Oonsiri, P.
2016-03-01
The purpose of this study is to determine the dose delivery effect of the different Beam ON interval in Flattening Filter Free Stereotactic Body Radiation Therapy (FFF-SBRT). The three 10MV-FFF SBRT plans (2 half rotating Rapid Arc, 9 to10 Gray/Fraction) were selected and irradiated in three different intervals (100%, 50% and 25%) using the RPM gating system. The plan verification was performed by the ArcCHECK for gamma analysis and the ionization chamber for point dose measurement. The dose delivery time of each interval were observed. For gamma analysis (2%&2mm criteria), the average percent pass of all plans for 100%, 50% and 25% intervals were 86.1±3.3%, 86.0±3.0% and 86.1±3.3%, respectively. For point dose measurement, the average ratios of each interval to the treatment planning were 1.012±0.015, 1.011±0.014 and 1.011±0.013 for 100%, 50% and 25% interval, respectively. The average dose delivery time was increasing from 74.3±5.0 second for 100% interval to 154.3±12.6 and 347.9±20.3 second for 50% and 25% interval, respectively. The same quality of the dose delivery from different Beam ON intervals in FFF-SBRT by TrueBEAM was illustrated. While the 100% interval represents the breath-hold treatment technique, the differences for the free-breathing using RPM gating system can be treated confidently.
Confidence Intervals for Squared Semipartial Correlation Coefficients: The Effect of Nonnormality
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.; Penfield, Randall D.
2010-01-01
The increase in the squared multiple correlation coefficient ([delta]R[superscript 2]) associated with a variable in a regression equation is a commonly used measure of importance in regression analysis. Algina, Keselman, and Penfield found that intervals based on asymptotic principles were typically very inaccurate, even though the sample size…
Confidence Intervals for Squared Semipartial Correlation Coefficients: The Effect of Nonnormality
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.; Penfield, Randall D.
2010-01-01
The increase in the squared multiple correlation coefficient ([delta]R[superscript 2]) associated with a variable in a regression equation is a commonly used measure of importance in regression analysis. Algina, Keselman, and Penfield found that intervals based on asymptotic principles were typically very inaccurate, even though the sample size…
The effect of ratio and interval training on Pavlovian-instrumental transfer in mice.
Wiltgen, Brian J; Sinclair, Courtney; Lane, Chadrick; Barrows, Frank; Molina, Martín; Chabanon-Hicks, Chloe
2012-01-01
Conditional stimuli (CS) that are paired with reward can be used to motivate instrumental responses. This process is called Pavlovian-instrumental transfer (PIT). A recent study in rats suggested that habitual responses are particularly sensitive to the motivational effects of reward cues. The current experiments examined this idea using ratio and interval training in mice. Two groups of animals were trained to lever press for food pellets that were delivered on random ratio or random interval schedules. Devaluation tests revealed that interval training led to habitual responding while ratio training produced goal-directed actions. The presentation of CSs paired with reward led to positive transfer in both groups, however, the size of this effect was much larger in mice that were trained on interval schedules. This result suggests that habitual responses are more sensitive to the motivational influence of reward cues than goal-directed actions. The implications for neurobiological models of motivation and drug seeking behaviors are discussed.
The Effect of Ratio and Interval Training on Pavlovian-Instrumental Transfer in Mice
Wiltgen, Brian J.; Sinclair, Courtney; Lane, Chadrick; Barrows, Frank; Molina, Martín; Chabanon-Hicks, Chloe
2012-01-01
Conditional stimuli (CS) that are paired with reward can be used to motivate instrumental responses. This process is called Pavlovian-instrumental transfer (PIT). A recent study in rats suggested that habitual responses are particularly sensitive to the motivational effects of reward cues. The current experiments examined this idea using ratio and interval training in mice. Two groups of animals were trained to lever press for food pellets that were delivered on random ratio or random interval schedules. Devaluation tests revealed that interval training led to habitual responding while ratio training produced goal-directed actions. The presentation of CSs paired with reward led to positive transfer in both groups, however, the size of this effect was much larger in mice that were trained on interval schedules. This result suggests that habitual responses are more sensitive to the motivational influence of reward cues than goal-directed actions. The implications for neurobiological models of motivation and drug seeking behaviors are discussed. PMID:23144742
ERP old/new effects at different retention intervals in recency discrimination tasks.
Curran, Tim; Friedman, William J
2004-01-01
Recognition memory studies have suggested that event-related brain potentials (ERPs) may tap into several different memory processes. In particular, two ERP components have been hypothesized as related to familiarity (FN400 old/new effect, 300-500 ms, anterior) and recollection processes (parietal old/new effect, 400-800 ms, posterior). The functional significance of the FN400 old/new effect is uncertain because similar old/new differences have been shown to disappear at moderately long retention intervals. The present study investigated the effects of retention interval (34 min, 39 min, or 1 day) on the FN400 and parietal old/new effects in two different recency discrimination tasks. The results suggest that the FN400 old/new effect can be maintained across 1-day retention intervals, so it may index brain processes capable of contributing to long-term memory.
Jackson, Dan; Bowden, Jack; Baker, Rose
2015-12-01
Moment-based estimators of the between-study variance are very popular when performing random effects meta-analyses. This type of estimation has many advantages including computational and conceptual simplicity. Furthermore, by using these estimators in large samples, valid meta-analyses can be performed without the assumption that the treatment effects follow a normal distribution. Recently proposed moment-based confidence intervals for the between-study variance are exact under the random effects model but are quite elaborate. Here, we present a much simpler method for calculating approximate confidence intervals of this type. This method uses variance-stabilising transformations as its basis and can be used for a very wide variety of moment-based estimators in both the random effects meta-analysis and meta-regression models.
Effect of delivery season on subsequent birth interval in early 20th century in Japan
NASA Astrophysics Data System (ADS)
Nonaka, K.
1989-12-01
Questionnaires of birth dates of family members (13 404 families in total) were analyzed in order to examine the effects of delivery season of a baby on the subsequent birth interval. Deliveries at maternal age of 20 34 years were used. In 1921 1935, the mothers who had been delivered of a baby in August October showed the shortest (30.62 months geometric mean) and those in February April the longest (34.05 months) non-last intervals, with a highly significant difference among the four delivery seasons ( P<0.001, Kruskal-Wallis test, n=5678). Although the intervals were abruptly prolonged just before the last birth, the above difference was also consistent in the last intervals. When seasonal distributions of last and non-last births were compared, last births tended to be concentrated in the summer half of a year ( P<0.05) in 1921 1935. In 1951 1965, overall geometric mean of the interval shortened to 28.44 months, and the length of intervals did not differ appreciably according to the season of preceding delivery. Deliveries in late summer (August October) in 1921 1935, therefore, were associated with increased risk of termination of reproduction, on one hand, but a lowered chance of prolongation of the subsequent interval, on the other hand. Possible environmental factors are discussed to explain this apparently paradoxical phenomenon.
Johnson, Robert N; Ward, Ryan D; Odum, Amy L
2010-05-01
Length of baseline training influences how methamphetamine disrupts temporal performance under a peak interval schedule. Acute methamphetamine produces overestimation of time following relatively brief training, but following extended training, methamphetamine produces more general loss of stimulus control. The current study extends the study of training length on the effects of methamphetamine to an interval-bisection procedure. Six pigeons responded under a psychophysical choice procedure in which responses to one key color were correct after presentation of four shorter sample durations and responses to another key color were correct after presentation of four longer sample durations. One group of three pigeons received briefer baseline training (45 sessions), while another group received more extended training (223 sessions) prior to methamphetamine administration. There was no evidence of overestimation of time or generalized loss of stimulus control in either group. Sensitivity (precision of timing) was higher in the group with more extensive training and was disrupted by methamphetamine.
Cost Effectiveness and Screening Interval of Lipid Screening in Hodgkin's Lymphoma Survivors
Chen, Aileen B.; Punglia, Rinaa S.; Kuntz, Karen M.; Mauch, Peter M.; Ng, Andrea K.
2009-01-01
Purpose Survivors of Hodgkin's lymphoma (HL) who received mediastinal irradiation have an increased risk of coronary heart disease. We evaluated the cost effectiveness of lipid screening in survivors of HL and compared different screening intervals. Methods We developed a decision-analytic model to evaluate lipid screening in a hypothetical cohort of 30-year-old survivors of HL who survived 5 years after mediastinal irradiation. We compared the following strategies: no screening, and screening at 1-, 3-, 5-, or 7-year intervals. Screen-positive patients were treated with statins. Markov models were used to calculate life expectancy, quality-adjusted life expectancy, and lifetime costs. Baseline probabilities, transition probabilities, and utilities were derived from published studies and US population data. Costs were estimated from Medicare fee schedules and the medical literature. Sensitivity analyses were performed. Results Using an incremental cost-effectiveness ratio (ICER) threshold of $100,000 per quality-adjusted life-year (QALY) saved, lipid screening at every interval was cost effective relative to a strategy of no screening. When comparing screening intervals, a 3-year interval was cost effective relative to a 5-year interval, but annual screening, relative to screening every 3 years, had an ICER of more than $100,000/QALY saved. Factors with the most influence on the results included risk of cardiac events/death after HL, efficacy of statins in reducing cardiac events/death, and costs of statins. Conclusion Lipid screening in survivors of HL, with statin therapy for screen-positive patients, improves survival and is cost effective. A screening interval of 3 years seems reasonable in the long-term follow-up of survivors of HL. PMID:19752333
Kim, S Y; Song, M K; Kim, M-S; Kim, E H; Han, D W
2014-09-01
Female sex and age more than 65 years are common risk factors for the development of torsades de pointes in association with heart rate-corrected QT (QTc) interval prolongation, which can be induced by tracheal intubation during general anaesthesia. However, the administration of remifentanil can prevent intubation-induced QTc interval prolongation. We compared sex-related differences in the effect-site concentration (Ce) of remifentanil for preventing QTc interval prolongation among elderly patients. Twenty-two female and 22 male patients older than 65 years were enrolled. Anaesthesia was induced with remifentanil and propofol using a target-controlled infusion. The Ce of remifentanil for maintaining a QTc interval prolongation <15 ms following intubation was determined for each sex using the isotonic regression method and a bootstrapping approach following Dixon's up-and-down method. The Ce of remifentanil for preventing QTc interval prolongation following intubation in 50 % of the population (EC50) and 95 % of the population (EC95) were significantly lower in females than in males. Isotonic regression revealed that the EC50 (83 % confidence interval) of remifentanil was 3.50 (2.95-4.08) ng/mL in females and 4.38 (4.08-4.63) ng/mL in males. The EC95 (95 % confidence interval) of remifentanil was 4.43 (4.25-4.48) ng/mL in females and 4.94 (4.78-4.98) ng/mL in males. Target-controlled infusion of remifentanil is effective in attenuating QTc interval prolongation after intubation among elderly patients and the Ce of remifentanil is lower in females than in males.
Pinkston, Jonathan W; Branch, Marc N
2004-01-01
Daily administration of cocaine often results in the development of tolerance to its effects on responding maintained by fixed-ratio schedules. Such effects have been observed to be greater when the ratio value is small, whereas less or no tolerance has been observed at large ratio values. Similar schedule-parameter-dependent tolerance, however, has not been observed with fixed-interval schedules arranging comparable interreinforcement intervals. This experiment examined the possibility that differences in rate and temporal patterning between the two types of schedule are responsible for the differences in observed patterns of tolerance. Five pigeons were trained to key peck on a three-component multiple (tandem fixed-interval fixed-ratio) schedule. The interval values were 10, 30, and 120 s; the tandem ratio was held constant at five responses. Performance appeared more like that observed under fixed-ratio schedules than fixed-interval schedules. Effects of various doses of cocaine given weekly were then determined for each pigeon. A dose that reduced responding was administered prior to each session for 50 days. A reassessment of effects of the range of doses revealed tolerance. The degree of tolerance was similar across components of the multiple schedule. Next, the saline vehicle was administered prior to each session for 50 days to assess the persistence of tolerance. Tolerance diminished in all subjects. Overall, the results suggested that schedule-parameter-dependent tolerance does not depend on the temporal pattern of responding engendered by fixed-ratio schedules. PMID:15693524
Fukuda, Hitoshi; Morita, Yukie; Shiotani, Norio; Mizuo, Midori; Komae, Norihisa
2004-08-01
The potential for QT interval prolongation of pazufloxacin mesilate (PZFX mesilate), a new quinolone antibacterial agent for intravenous use, was investigated by in vitro and in vivo electrophysiology studies. Following results were obtained. In vitro electrophysiology study using guinea pig papillary muscles: PZFX mesilate (30-300 microM) had no effects on resting membrane potential (RMP), action potential amplitude (APA) and action potential duration (APD). Reference quinolones, sparfloxacin (3-30 microM) and moxifloxacin (10-100 microM), had no effects on RMP and APA, but significantly prolonged APD at more than 3 and 10 microM, respectively, while ciprofloxacin (10-100 microM) had no effect on each parameter. In vivo electrophysiology study using anesthetized dogs: PZFX mesilate had no effects on electrocardiograph parameter (PR interval, QRS interval, QT interval and QTc) after intravenous administration of 3-30 mg/kg. These results suggest that PZFX mesilate has low potential for QT interval prolongation.
ERIC Educational Resources Information Center
Sapp, Marty
2012-01-01
Like many journals within education, for "Multicultural Learning and Teaching," this writer found little written on measurement, effect sizes, and confidence intervals; therefore, the purpose of this article is to address these factors. The effect of not addressing these issues is that a basic foundation of science cannot be established…
ERIC Educational Resources Information Center
Sapp, Marty
2012-01-01
Like many journals within education, for "Multicultural Learning and Teaching," this writer found little written on measurement, effect sizes, and confidence intervals; therefore, the purpose of this article is to address these factors. The effect of not addressing these issues is that a basic foundation of science cannot be established…
ERIC Educational Resources Information Center
Hannon, Erin E.; Soley, Gaye; Levine, Rachel S.
2011-01-01
Effects of culture-specific experience on musical rhythm perception are evident by 12 months of age, but the role of culture-general rhythm processing constraints during early infancy has not been explored. Using a habituation procedure with 5- and 7-month-old infants, we investigated effects of temporal interval ratio complexity on discrimination…
The effect of a brief sprint interval exercise on growth factors and inflammatory mediators.
Meckel, Yoav; Eliakim, Alon; Seraev, Mariana; Zaldivar, Frank; Cooper, Dan M; Sagiv, Michael; Nemet, Dan
2009-01-01
Exercise training efficiency depends on the intensity, volume, duration, and frequency of training, as well as on the athlete's ability to tolerate it. Recent efforts to quantify the effects of aerobic exercise training on hormonal response have suggested that exercise leads to simultaneous changes of antagonistic mediators. The effects of anaerobic exercise on these mediators are not known. Therefore, the aim of the present study was to evaluate the effects of a brief sprint interval session on the balance between anabolic (growth hormone [GH]--> insulin-like growth factor [IGF]-I axis) and catabolic hormones (cortisol), and circulating inflammatory cytokines such as interleukin (IL)-6. Twelve healthy elite junior handball players (17-20 years) participated in the study. Exercise consisted of a 4 x 250-m run on a treadmill, at a constant intensity of 80% of the personal maximal speed. Each run was separated by 3 minutes of rest. Blood samples were collected before, immediately after each 250-m run, and 1 hour after the last run. Exercise led to significant increases in GH (0.3 +/- 0.2 to 5.1 +/- 2.2 ngxml, p < 0.05), IGF binding protein (IGFBP)-3 (4191 +/- 2.48 to 4875 +/- 301 ngxml, p < 0.05), IL-6 (1.3 +/- 0.2 to 2.1 +/- 0.3 pgxml, p < 0.002), testosterone, and testosterone/cortisol ratio, and to a significant decrease in IGFBP-1 levels. Levels of IL-6 remained elevated 1 hour after the end of exercise. Exercise had no significant effects on IGF-I and cortisol levels. Changes in the GH-IGF-I axis and testosterone/cortisol ratio after the brief sprint interval exercise suggested exercise-related anabolic adaptations. The increase in IL-6 may indicate its important role in muscle tissue repair after anaerobic exercise. Changes in the anabolic-catabolic hormonal balance and in inflammatory mediators can be used as an objective tool to gauge the training intensity of different types of anaerobic exercises and training periods.
Shaw, Kate A; Topp, Nicole J; Shaw, Jonathan G; Blumenthal, Paul D
2013-06-01
To examine the effect of the interval between mifepristone and misoprostol administration on induction time (first misoprostol dose to abortion), total procedure time (mifepristone administration to abortion), and safety and efficacy in second-trimester induction abortion (13-24 weeks). We searched MEDLINE (1966-2012), ClinicalTrials.gov, POPLINE, and the Cochrane Controlled Trials Register using search terms for second trimester, abortion, misoprostol, and mifepristone and reviewed reference lists of published reports. Our search revealed 138 articles of which 29 met inclusion criteria: 20 randomized controlled trials and nine observational studies. Studies were included if, in any study arm, mifepristone and misoprostol were used for medical abortion in the second trimester. Two authors independently reviewed the articles and abstracted the data using standardized data abstraction templates to summarize data. Discrepancies were resolved by consensus. Three studies directly compared a 1-day to 2-day mifepristone-misoprostol interval; they showed small differences in median induction times (weighted average 7.3 hours, range 7-8.5 for a 1-day interval; weighted average 6.8 hours, range 6.3-7.2 for a 2-day interval) and no significant difference in percent expelled by 12 hours or 24 hours. When all randomized studies using mifepristone and misoprostol were pooled by comparable mifepristone-misoprostol interval and misoprostol dose, induction times (first misoprostol dose to expulsion) were only 1-2 hours longer for a 12- to 24-hour interval compared with a 36-48-hour interval, whereas total abortion times (mifepristone to expulsion) were at least 18 hours longer in the 36- to 48-hour group. Induction times varied by misoprostol dosing, with 400-microgram misoprostol protocols resulting in shorter induction times than 200-microgram protocols. Shortening the mifepristone-misoprostol interval, thereby reducing total abortion time, does not compromise the safety or
Gyarmathy, V Anna; Johnston, Lisa G; Caplinskiene, Irma; Caplinskas, Saulius; Latkin, Carl A
2014-02-01
Respondent driven sampling (RDS) and incentivized snowball sampling (ISS) are two sampling methods that are commonly used to reach people who inject drugs (PWID). We generated a set of simulated RDS samples on an actual sociometric ISS sample of PWID in Vilnius, Lithuania ("original sample") to assess if the simulated RDS estimates were statistically significantly different from the original ISS sample prevalences for HIV (9.8%), Hepatitis A (43.6%), Hepatitis B (Anti-HBc 43.9% and HBsAg 3.4%), Hepatitis C (87.5%), syphilis (6.8%) and Chlamydia (8.8%) infections and for selected behavioral risk characteristics. The original sample consisted of a large component of 249 people (83% of the sample) and 13 smaller components with 1-12 individuals. Generally, as long as all seeds were recruited from the large component of the original sample, the simulation samples simply recreated the large component. There were no significant differences between the large component and the entire original sample for the characteristics of interest. Altogether 99.2% of 360 simulation sample point estimates were within the confidence interval of the original prevalence values for the characteristics of interest. When population characteristics are reflected in large network components that dominate the population, RDS and ISS may produce samples that have statistically non-different prevalence values, even though some isolated network components may be under-sampled and/or statistically significantly different from the main groups. This so-called "strudel effect" is discussed in the paper. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
Sandbakk, Øyvind; Sandbakk, Silvana B; Ettema, Gertjan; Welde, Boye
2013-07-01
The purpose of this study was to test whether a long duration of aerobic high-intensity interval training is more effective than shorter intervals at a higher intensity in highly trained endurance athletes. The sample comprised of 12 male and 9 female, national-level, junior cross-country skiers (age, 17.5 ± 0.4 years, maximal oxygen uptake (V[Combining Dot Above]O2max): 67.4 ± 7.7 ml min kg), who performed 8-week baseline and 8-week intervention training periods on dry land. During the intervention period, a short-interval group (SIG, n = 7) added 2 weekly sessions with short duration intervals (2- to 4-minute bouts, total duration of 15-20 minutes), a long-interval group (LIG; n = 7) added 2 weekly sessions with long duration intervals (5- to 10-minute bouts, total duration of 40-45 minutes). The interval sessions were performed with the athletes' maximal sustainable intensity. A control group (CG; n = 7) added 2 weekly sessions with low-intensity endurance training at 65-74% of maximal heart rate. Before and after the intervention period, the skiers were tested for time-trial performance on 12-km roller-ski skating and 7-km hill run. V[Combining Dot Above]O2max and oxygen uptake at the ventilatory threshold (V[Combining Dot Above]O2VT) were measured during treadmill running. After the intervention training period, the LIG-improved 12-km roller ski, 7-km hill run, V[Combining Dot Above]O2max, and V[Combining Dot Above]O2VT by 6.8 ± 4.0%, 4.8 ± 2.6%, 3.7 ± 1.6%, and 5.8 ± 3.3%, respectively, from pre- to posttesting, and improved both performance tests and V[Combining Dot Above]O2VT when compared with the SIG and the CG (all p < 0.05). The SIG improved V[Combining Dot Above]O2max by 3.5 ± 3.2% from pre- to posttesting (p < 0.05), whereas the CG remained unchanged. As hypothesized, a long duration of aerobic high-intensity interval training improved endurance performance and oxygen uptake at the ventilatory threshold more than shorter intervals at a higher
Perkins, Steven E; Jelinek, Herbert F; Al-Aubaidy, Hayder A; de Jong, Berverlie
2017-03-01
Recovery of cardiac autonomic modulation following exercise can be measured using heart rate variability. The objective of this study was to investigate and compare recovery of autonomic cardiac regulation over three days following a single session of high intensity interval training compared to endurance training. Nine untrained students completed two exercise protocols in a one-way crossover design. The endurance protocol consisted of 45min of moderate intensity cycling, and the high intensity interval protocol of six 30s sets of high intensity cycling. Cardiac autonomic activity recovery was measured over three days post-exercise for two hours immediately following each exercise session and each morning thereafter using linear and nonlinear heart rate variability analysis. Both linear and nonlinear measures were significantly decreased immediately following exercise indicating loss of vagal activity. Root mean sum of squared differences (p=0.031) and high frequency (p=0.031) were suppressed following the interval exercise only. The long term correlation of the heart rate applying detrended fluctuation analysis was decreased immediately following endurance training (p=0.039) and trended to increase immediately following the interval protocol (p=0.156). Sample entropy was decreased immediately following both the endurance (p=0.023) and interval (p=0.031) protocols. No exercise effects were noted from 24h post exercise onwards. High intensity interval training had a greater impact on neurocardiac activity than moderate intensity endurance training as indicated by both linear and nonlinear heart rate variability measures. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Acciavatti, Tiziano; Martinotti, Giovanni; Corbo, Mariangela; Cinosi, Eduardo; Lupi, Matteo; Ricci, Fabrizio; Di Scala, Rosa; D'Ugo, Emilia; De Francesco, Viola; De Caterina, Raffaele; di Giannantonio, Massimo
2017-04-01
We aimed to investigate in a clinical setting, the effects of different classes of psychotropic drugs on cardiac electrophysiological measures linked with an increased risk of sudden cardiac death. We conducted a cross-sectional study in a population of 1059 psychiatric inpatients studying the effects of various psychotropic drugs on the T-peak to T-end (TpTe) interval, QT dispersion and QT interval. Methadone use showed a strong association with TpTe prolongation (odds ratio (OR)=12.66 (95% confidence interval (CI), 3.9-41.1), p<0.001), an effect independent from action on QT interval. Mood stabilisers showed significant effects on ventricular repolarisation: lithium was associated with a TpTe prolongation (OR=2.12 (95% CI, 1.12-4), p=0.02), while valproic acid with a TpTe reduction (OR=0.6 (95% CI, 0.37-0.98), p=0.04). Among antipsychotics, clozapine increased TpTe (OR=9.5 (95% CI, 2.24-40.39), p=0.002) and piperazine phenothiazines increased QT dispersion (OR=2.73 (95% CI, 1.06-7.02), p=0.037). Treatment with psychotropic drugs influences TpTe and QT dispersion. These parameters might be considered to better estimate the sudden cardiac death risk related to specific medications. Beyond antipsychotics and antidepressants, mood stabilisers determine significant effects on ventricular repolarisation.
Effects of sevoflurane or ketamine on the QTc interval during electroconvulsive therapy.
Erdil, Feray; Begeç, Zekine; Kayhan, Gülay Erdoğan; Yoloğlu, Saim; Ersoy, Mehmet Özcan; Durmuş, Mahmut
2015-04-01
To evaluate the effect of sevoflurane or ketamine on the corrected QT (QTc) interval and the interval from the peak to the end of the T wave (Tp-e) during electroconvulsive therapy (ECT) in patients with major depression. This prospective, randomized, double-blinded study included 24 patients that were randomly allocated to receive sevoflurane (group S) or ketamine (group K) for ECT session. Group S patients received 8 % sevoflurane for anesthesia induction, which was maintained at 2-4 % until delivery of the electrical stimulus. Group K patients received a bolus of ketamine (1 mg/kg). The mean arterial pressure (MAP) and heart rate (HR) and the electrocardiogram (ECG) were recorded before (T1) and after induction of anesthesia (T2) and 0, 1, 3, and 10 min after the electrical stimuli ended (T3, T4, T5, and T6, respectively). In both groups, the QTc interval was significantly longer at T2, T4, T5, and T6 than at baseline. The QTc interval was longer at T4, T5, and T6 in group S compared to that in group K, the Tp-e interval was significantly longer at T4 in group K both baseline and group S. The HR in group S was increased at T4 compared with group K. MAP was significantly higher after induction of anesthesia in group K compared to those in group S at all time points. Although group S showed a prolonged QTc interval after ECT compared to group K, the Tp-e interval in both groups was not significantly affected clinically. Sevoflurane blunted MAP and peak HR.
Psycho-Physical Effects of Varied Rest Intervals Following Warm-Up.
ERIC Educational Resources Information Center
Aronchick, Joel; Burke, Edmund J.
This study assessed the effects of varied rest intervals following a five-minute warm-up upon subsequent ratings of perceived exertion (RPE), heart rate (HR), and state anxiety during an exercise period. The subjects were 16 male college students. Each subject was tested under four experimental conditions following a five-minute warm-up on a…
A Note on Confidence Intervals for Two-Group Latent Mean Effect Size Measures
ERIC Educational Resources Information Center
Choi, Jaehwa; Fan, Weihua; Hancock, Gregory R.
2009-01-01
This note suggests delta method implementations for deriving confidence intervals for a latent mean effect size measure for the case of 2 independent populations. A hypothetical kindergarten reading example using these implementations is provided, as is supporting LISREL syntax. (Contains 1 table.)
ERIC Educational Resources Information Center
Jentzsch, Ines; Leuthold, Hartmut
2005-01-01
In serial choice reaction time (RT) tasks, performance in each trial critically depends on the sequence of preceding events. In this study, the authors specifically examined the mechanism underlying RT sequence effects at short response-stimulus intervals (RSIs), in which performance is impaired in the current trial N if events alternate rather…
Effect Sizes and their Intervals: The Two-Level Repeated Measures Case
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.; Penfield, Randall D.
2005-01-01
Probability coverage for eight different confidence intervals (CIs) of measures of effect size (ES) in a two-level repeated measures design was investigated. The CIs and measures of ES differed with regard to whether they used least squares or robust estimates of central tendency and variability, whether the end critical points of the interval…
Wong, Pui-lam; Chaouachi, Anis; Chamari, Karim; Dellal, Alexandre; Wisloff, Ulrik
2010-03-01
This study examined the effect of concurrent muscular strength and high-intensity running interval training on professional soccer players' explosive performances and aerobic endurance. Thirty-nine players participated in the study, where both the experimental group (EG, n = 20) and control group (CG, n = 19) participated in 8 weeks of regular soccer training, with the EG receiving additional muscular strength and high-intensity interval training twice per week throughout. Muscular strength training consisted of 4 sets of 6RM (repetition maximum) of high-pull, jump squat, bench press, back half squat, and chin-up exercises. The high-intensity interval training consisted of 16 intervals each of 15-second sprints at 120% of individual maximal aerobic speed interspersed with 15 seconds of rest. EG significantly increased (p < or = 0.05) 1RM back half squat and bench press but showed no changes in body mass. Within-subject improvement was significantly higher (p < or = 0.01) in the EG compared with the CG for vertical jump height, 10-m and 30-m sprint times, distances covered in the Yo-Yo Intermittent Recovery Test and maximal aerobic speed test, and maximal aerobic speed. High-intensity interval running can be concurrently performed with high load muscular strength training to enhance soccer players' explosive performances and aerobic endurance.
The use of behavioral test batteries, II: effect of test interval.
Paylor, Richard; Spencer, Corinne M; Yuva-Paylor, Lisa A; Pieke-Dahl, Sandra
2006-01-30
Test batteries are commonly used to assess the behavioral phenotype of genetically modified and inbred strains of mice. However, few systematic studies have been employed to address several key issues concerning the use of a test battery. The current study was designed to address whether inter-test interval affects behavioral performance. Male mice of 3 different inbred strains and one F1 hybrid strain were randomly assigned to either a test battery with 1 week inter-test intervals, or a rapid test battery with 1-2 day inter-test intervals. The test battery included a neurological exam, open-field activity, light-dark exploration, rotarod test, prepulse inhibition, and startle habituation. The experiment was repeated with female animals of 2 different strains. As expected, there were strain differences on each of the behavioral assays; however, there was no major difference in performance between mice of the standard test battery and the rapid test battery. Similar results were found with females. These results indicate that the interval between most tests could be as little as 1-2 days, with little significant effect on overall performance. Thus, it is possible with the current test battery to reduce the inter-test interval to facilitate the rate of studying and identifying behavioral phenotypes in mice.
Bouts of responding on variable-interval schedules: effects of deprivation level.
Shull, Richard L
2004-01-01
Rats obtained food pellets on a variable-interval schedule of reinforcement by nose poking a lighted key. After training to establish baseline performance (with the mean variable interval set at either 60, 120, or 240 s), the rats were given free access to food during the hour just before their daily session. This satiation operation reduced the rate of key poking. Analysis of the interresponse time distributions (log survivor plots) indicated that key poking occurred in bouts. Prefeeding lengthened the pauses between bouts, shortened the length of bouts (less reliably), and had a relatively small decremental effect on the response rate within bouts. That deprivation level affects mainly between-bout pauses has been reported previously with fixed-ratio schedules. Thus, when the focus is on bouts, the performances maintained by variable-interval schedules and fixed-ratio schedules are similarly affected by deprivation. PMID:15239490
The effects of soil environment on postmortem interval: a macroscopic analysis.
Jaggers, Kimberley A; Rogers, Tracy L
2009-11-01
Burial environment, in particular soil moisture, has a significant impact on the type, rate, and extent of bone degradation, which ultimately affects estimations of the postmortem interval (PMI). The purpose of this research is to determine the effects of soil moisture on the color, weight, condition, and texture of bone as it relates to the PMI. Bone changes occurring over two different time intervals (2 and 5 months) were examined using 120 sus scrofa leg bones. During each time interval bones were buried in two soil environments, one of which was drier than the other. The bones in both environments lost weight over time but the net weight loss was greater for bones in the higher moisture environment. There was no change in color, texture, or overall condition, indicating that 150 days is not long enough for such alterations to occur, regardless of the moisture level of the burial environment.
The effects of initial interval size on the efficacy of DRO schedules of reinforcement.
Repp, A C; Felce, D; Barton, L E
1991-01-01
The differential reinforcement of other behavior (DRO) is a behavior-reduction procedure that has been popular for several years. In classroom settings, it provides reinforcement when a student does not display inappropriate responding for a particular interval of time. Unfortunately, relatively little is known about how to use DRO effectively in applied settings. Most research has been conducted in laboratory settings; the purpose of the present study was to provide a replication of one of those studies. This study examined the effect of the size of the initial DRO interval on the disruptive behavior of students with moderate disabilities. In the first experiment, a group of six students was observed during baseline in two classes. Two different DRO values were then used. In one classroom, it was equal to the mean number of 10-second intervals between disruptions during baseline. In the other classroom, it was twice the mean number during baseline. In the final phase, behavior in both classrooms was put under the same DRO program. In the second experiment, the disruptive behavior of three students was studied in a different design in which both methods of determining the initial DRO value were compared. The results of both experiments showed that an initial DRO value equal to the mean number of intervals between responses in baseline was much more effective than a value twice that size in reducing disruptions.
Effects of temporal shapes of sound markers on the perception of interonset time intervals.
Hasuo, Emi; Nakajima, Yoshitaka; Osawa, Satoshi; Fujishima, Hiroyuki
2012-02-01
This study investigated how the temporal characteristics, particularly durations, of sounds affect the perceived duration of very short interonset time intervals (120-360 ms), which is important for rhythm perception in speech and music. In four experiments, the subjective duration of single time intervals marked by two sounds was measured utilizing the method of adjustment, while the markers' durations, amplitude difference (which accompanied the duration change), and sound energy distribution in time were varied. Lengthening the duration of the second marker in the range of 20-100 ms increased the subjective duration of the time interval in a stable manner. Lengthening the first marker tended to increase the subjective duration, but unstably; an opposite effect sometimes appeared for the shortest time interval of 120 ms. The effects of varying the amplitude and the sound energy distribution in time of either marker were very small in the present experimental conditions, thus proving the effects of marker durations per se.
Xu, Ying; Lam, K F; Cowling, Benjamin J; Cheung, Yin Bun
2015-01-30
Outcome variables that are semicontinuous with clumping at zero are commonly seen in biomedical research. In addition, the outcome measurement is sometimes subject to interval censoring and a lower detection limit (LDL). This gives rise to interval-censored observations with clumping below the LDL. Level of antibody against influenza virus measured by the hemagglutination inhibition assay is an example. The interval censoring is due to the assay's technical procedure. The clumping below LDL is likely a result of the lack of prior exposure in some individuals such that they either have zero level of antibodies or do not have detectable level of antibodies. Given a pair of such measurements from the same subject at two time points, a binary 'fold-increase' endpoint can be defined according to the ratio of these two measurements, as it often is in vaccine clinical trials. The intervention effect or vaccine immunogenicity can be assessed by comparing the binary endpoint between groups of subjects given different vaccines or placebos. We introduce a two-part random effects model for modeling the paired interval-censored data with clumping below the LDL. Based on the estimated model parameters, we propose to use Monte Carlo approximation for estimation of the 'fold-increase' endpoint and the intervention effect. Bootstrapping is used for variance estimation. The performance of the proposed method is demonstrated by simulation. We analyze antibody data from an influenza vaccine trial for illustration.
Gabriel, Brendan Morris; Pugh, Jamie; Pruneta-Deloche, Valerie; Moulin, Philippe; Ratkevicius, Aivaras; Gray, Stuart Robert
2013-01-01
Postprandial phenomenon are thought to contribute to atherogenesis alongside activation of the immune system. A single bout of high intensity interval exercise attenuates postprandial triacylglycerol (TG), although the longevity and mechanisms underlying this observation are unknown. The aims of this study were to determine whether this attenuation in postprandial TG remained 2 days after high intensity interval exercise, to monitor markers of leukocyte activation and investigate the underlying mechanisms. Eight young men each completed two three day trials. On day 1: subjects rested (Control) or performed 5 x 30 s maximal sprints (high intensity interval exercise). On day 2 and 3 subjects consumed high fat meals for breakfast and 3 h later for lunch. Blood samples were taken at various times and analysed for TG, glucose and TG-rich lipoprotein (TRL)-bound LPL-dependent TRL-TG hydrolysis (LTTH). Flow cytometry was used to evaluate granulocyte, monocyte and lymphocyte CD11b and CD36 expression. On day 2 after high intensity interval exercise TG area under the curve was lower (P<0.05) (7.46 ± 1.53 mmol/l/7h) compared to the control trial (9.47 ± 3 .04 mmol/l/7h) with no differences during day 3 of the trial. LTTH activity was higher (P<0.05) after high intensity interval exercise, at 2 hours of day 2, compared to control. Granulocyte, monocyte and lymphocyte CD11b expression increased with time over day 2 and 3 of the study (P<0.0001). Lymphocyte and monocyte CD36 expression decreased with time over day 2 and 3 (P<0.05). There were no differences between trials in CD11b and CD36 expression on any leukocytes. A single session of high intensity interval exercise attenuated postprandial TG on day 2 of the study, with this effect abolished by day 3.The reduction in postprandial TG was associated with an increase in LTTH. High intensity interval exercise had no effect on postprandial responses of CD11b or CD36.
Outcome pre- and postexposure effects: retention interval interacts with primacy and recency.
Urushihara, Kouji; Wheeler, Daniel S; Miller, Ralph R
2004-10-01
Effects of outcome-alone pretraining and posttraining exposure were investigated in conditioned suppression experiments conducted within a sensory preconditioning preparation with rats. Experiment 1 found that interference by outcome postexposure was stronger than that by outcome preexposure, suggesting a recency effect. Experiment 2 found that after a long retention interval, outcome preexposure produced more interference than outcome postexposure, suggesting a shift from recency to primacy with increasing retention interval. Experiment 3 showed that presentation of a priming stimulus that had been embedded within the earlier phase of treatment also caused a shift from recency to primacy. These results suggest that, at least in a sensory preconditioning paradigm, retrievability of outcome-alone exposure memory is an important determinant of any outcome-alone exposure effect. Copyright 2004 American Psychological Association
Casey, R; Griffin, T P; Wall, D; Dennedy, M C; Bell, M; O'Shea, P M
2017-01-01
Background The Endocrine Society Clinical Practice Guideline on Phaeochomocytoma and Paraganglioma recommends phlebotomy for plasma-free metanephrines with patients fasted and supine using appropriately defined reference intervals. Studies have shown higher diagnostic sensitivities using these criteria. Further, with seated-sampling protocols, for result interpretation, reference intervals that do not compromise diagnostic sensitivity should be employed. Objective To determine the impact on diagnostic performance and financial cost of using supine reference intervals for result interpretation with our current plasma-free metanephrines fasted/seated-sampling protocol. Methods We conducted a retrospective cohort study of patients who underwent screening for PPGL using plasma-free metanephrines from 2009 to 2014 at Galway University Hospitals. Plasma-free metanephrines were measured using liquid chromatography-tandem mass spectrometry. Supine thresholds for plasma normetanephrine and metanephrine set at 610 pmol/L and 310 pmol/L, respectively, were used. Results A total of 183 patients were evaluated. Mean age of participants was 53.4 (±16.3) years. Five of 183 (2.7%) patients had histologically confirmed PPGL (males, n=4). Using seated reference intervals for plasma-free metanephrines, diagnostic sensitivity and specificity were 100% and 98.9%, respectively, with two false-positive cases. Application of reference intervals established in subjects supine and fasted to this cohort gave diagnostic sensitivity of 100% with specificity of 74.7%. Financial analysis of each pretesting strategy demonstrated cost-equivalence (€147.27/patient). Conclusion Our cost analysis, together with the evidence that fasted/supine-sampling for plasma-free metanephrines, offers more reliable exclusion of PPGL mandates changing our current practice. This study highlights the important advantages of standardized diagnostic protocols for plasma-free metanephrines to ensure the highest
Dalamitros, Athanasios A; Zafeiridis, Andreas S; Toubekis, Argyris G; Tsalis, George A; Pelarigo, Jailton G; Manou, Vasiliki; Kellis, Spiridon
2016-10-01
Dalamitros, AA, Zafeiridis, AS, Toubekis, AG, Tsalis, GA, Pelarigo, JG, Manou, V, and Kellis, S. Effects of short-interval and long-interval swimming protocols on performance, aerobic adaptations, and technical parameters: A training study. J Strength Cond Res 30(10): 2871-2879, 2016-This study compared 2-interval swimming training programs of different work interval durations, matched for total distance and exercise intensity, on swimming performance, aerobic adaptations, and technical parameters. Twenty-four former swimmers were equally divided to short-interval training group (INT50, 12-16 × 50 m with 15 seconds rest), long-interval training group (INT100, 6-8 × 100 m with 30 seconds rest), and a control group (CON). The 2 experimental groups followed the specified swimming training program for 8 weeks. Before and after training, swimming performance, technical parameters, and indices of aerobic adaptations were assessed. ΙΝΤ50 and ΙΝΤ100 improved swimming performance in 100 and 400-m tests and the maximal aerobic speed (p ≤ 0.05); the performance in the 50-m swim did not change. Posttraining V[Combining Dot Above]O2max values were higher compared with pretraining values in both training groups (p ≤ 0.05), whereas peak aerobic power output increased only in INT100 (p ≤ 0.05). The 1-minute heart rate and blood lactate recovery values decreased after training in both groups (p < 0.01). Stroke length increased in 100 and 400-m swimming tests after training in both groups (p ≤ 0.05); no changes were observed in stroke rate after training. Comparisons between groups on posttraining mean values, after adjusting for pretraining values, revealed no significant differences between ΙΝΤ50 and ΙΝΤ100 for all variables; however, all measures were improved vs. the respective values in the CON (p < 0.001-0.05). In conclusion, when matched for distance and exercise intensity, the short-interval (50 m) and long-interval (100 m) protocols confer analogous
Acosta-Materán, Carlos; Díaz-Oliva, Eloy; Fernández-Rodríguez, Diego; Hernández-Afonso, Julio
2016-01-01
A high percentage of patients having atrial fibrillation (AF) presents with paroxysmal AF. Flecainide, the prototypic class Ic anti-arrhythmic drug is the most effective drug to maintain sinus rhythm in this subgroup of patients, though the drug has potential pro-arrhythmic effects. Furthermore, the H1 receptor antagonists are the most commonly prescribed drugs for the symptomatic treatment of pruritus. Despite having low number of adverse effects, the H1 receptor antagonists have cardiotoxic effects. Flecainide and H1 receptor antagonists present arrhythmic complications including QT interval prolongation and torsade de pointes (TdP). The case presented here is a 65-year-old female who was diagnosed of atrial fibrillation and presented with rashes in lower extremities. The patient was treated using flecainide and H1 receptor antagonists (loratadine and hydroxyzine) that prolonged QT interval and induced TdP. The concomitant administration of flecainide and H1 receptor antagonists seems to have a synergistic effect in QT interval prolongation and subsequent TdP. The concurrent administration of H1 receptor antagonists to patients receiving class Ic anti-arrhythmic drugs should be avoided in order to reduce arrhythmic risk in this population. PMID:27440957
da Costa Santos, Vanessa Batista; de Paula Ramos, Solange; Milanez, Vinícius Flávio; Corrêa, Julio Cesar Molina; de Andrade Alves, Rubens Igor; Dias, Ivan Frederico Lupiano; Nakamura, Fábio Yuzo
2014-03-01
The aim of this study was to test, between two bouts of exercise, the effects of light-emitting diode (LED) therapy and cryotherapy regarding muscle damage, inflammation, and performance. Male Wistar rats were allocated in four groups: control, passive recovery (PR), cryotherapy (Cryo), and LED therapy. The animals were submitted to 45 min of swimming exercise followed by 25 min of recovery and then a second bout of either 45 min of exercise (muscle damage analysis) or time to exhaustion (performance). During the rest intervals, the rats were kept in passive rest (PR), submitted to cold water immersion (10 min, 10 °C) or LED therapy (940 nm, 4 J/cm(2)) of the gastrocnemius muscle. Blood samples were collected to analyze creatine kinase activity (CK), C-reactive protein (CRP), and leukocyte counts. The soleus muscles were evaluated histologically. Time to exhaustion was recorded during the second bout of exercise. After a second bout of 45 min, the results demonstrated leukocytosis in the PR and Cryo groups. Neutrophil counts were increased in all test groups. CK levels were increased in the Cryo group. CRP was increased in PR animals. The PR group presented a high frequency of necrosis, but the LED group had fewer necrotic areas. Edema formation was prevented, and fewer areas of inflammatory cells were observed in the LED group. The time to exhaustion was greater in both the LED and Cryo groups, without differences in CK levels. CRP was decreased in LED animals. We conclude that LED therapy and cryotherapy can improve performance, although LED therapy is more efficient in preventing muscle damage and local and systemic inflammation.
Effects of signaling on temporal control of behavior in response-initiated fixed intervals.
Fox, Adam E; Kyonka, Elizabeth G E
2016-11-01
Behavior and events distributed in time can serve as markers that signal delays to future events. The majority of timing research has focused on how behavior changes as the time to some event, usually food availability, decreases. The primary objective of the two experiments presented here was to assess how behavior changes as time passes between two time markers when the first time marker was manipulated but the second, food delivery, was held constant. Pigeons were exposed to fixed-interval, response-initiated fixed-interval, and signaled response-initiated fixed-interval 15- and 30-s schedules of reinforcement. In Experiment 1, first-response latencies were systematically shorter in the signaled response-initiated schedules than response-initiated schedules, suggesting that the first response was a more effective time marker when it was signaled. In Experiment 2, responding in no-food (i.e. "peak") trials indicated that timing accuracy was equivalent in the three schedule types. Compared to fixed interval schedules, timing precision was reduced in the signaled response-initiated schedules and was lowest in response-initiated schedules. Results from Experiments 1 and 2 coupled with previous research suggest that the overall "informativeness" of a time marker relative to other events and behaviors in the environment may determine its efficacy.
Effects of enzastaurin and its metabolites on the QT interval in cancer patients.
Welch, Pamela A; Ng, Wee Teck; Darstein, Christelle L; Musib, Luna; Lesimple, Thierry
2016-01-01
Preclinical and interim results from a clinical pharmacology study in patients with cancer indicated that enzastaurin might have the potential to prolong the QT. Rather than undertake a formal thorough QT study, the effect of enzastaurin on the QT was assessed by combining the QT corrected for heart rate (QTc) intervals from 3 clinical pharmacology studies totaling 85 patients with cancer receiving multiple therapeutic or supratherapeutic doses of enzastaurin. Neither a placebo nor an active control was used. Serial, replicate, time-matched electrocardiograms were collected during a no-drug baseline day and when enzastaurin and its major active metabolite, LSN326020, had achieved steady state. Plasma concentrations of enzastaurin and LSN326020 were determined at each electrocardiogram point to enable concentration-QT analyses. The cross-study analysis showed that enzastaurin resulted in a statistically significant prolongation of the QTc at therapeutic and supratherapeutic doses. At an enzastaurin maximum plasma concentration (Cmax ) of 3660 nmol/L, the predicted QTc using Fridericia's formula (QTcF) interval and its 90% confidence interval was 17.72 milliseconds (16.52-18.92 milliseconds). Likewise, at an LSN326020 Cmax value of 1718 nmol/L, the predicted QTcF interval was 20.23 milliseconds (18.72-21.74 milliseconds). The concentration-QTcF slopes for enzastaurin and LSN326020 were positive and statistically significantly different from zero (all P < .05). © 2015, The American College of Clinical Pharmacology.
The effect of an aerobic interval training program on intermittent anaerobic performance.
Gaiga, M C; Docherty, D
1995-12-01
The effects of a 9-week aerobic interval training program on anaerobic intermittent performance were investigated. Intermittent work consisted of four repeat 30-sec maximal efforts on a cycle ergometer (Wingate test) with 3-min recovery intervals. Thirteen men trained 3 days a week on the cycle ergometer, completing 3-min work-to-rest intervals and progressing from 5 to 10 reps. Relative and absolute values of aerobic power increased significantly for the training group (p < .05). No significant change was observed for the control group (n = 11). The training group demonstrated significant increases in the four anaerobic variables of short-term peak power (SPP), short-term anaerobic capacity (SAC), intermediate-term peak power (IPP), and total work (TW), and across the four 30-sec maximal repeats for anaerobic performance (T1-T4) (p < .05). Greater percentages of increase occurred for IPP and TW, especially during Repeats 3 and 4. The control group only demonstrated a significant increase in SPP for Repeat 3. These data suggest that the type of interval training program used in the study increased aerobic power and also enhanced performance in repeated high intensity, short duration work.
The effects of sex, age, and interval duration on the perception of time.
Hancock, P A; Rausch, R
2010-02-01
The present experiment examined the interactive effects of sex, age, and interval duration on individual's time perception accuracy. Participants engaged in the duration production task and subsequently completed questionnaires designed to elicit their temporal attitudes. The overall group of 100 individuals was divided evenly between the sexes. Five groups, each composed of 10 males and 10 females, were divided by decades of age ranging from 20 to 69 years old. The specific time estimation task was an empty interval production procedure composed of 50 trials on each of four different intervals of 1, 3, 7, and 20 s, respectively. The presentation orders of these intervals were randomized across participants but yoked across the sexes within each of the respective age groups. Analysis of the production results indicated significant influences for the sex of the participant while age did not appear to affect estimates of these short durations. Temporal attitudes, as reflected in responses to time questionnaire inquiries, did however exhibit significant differences across age. The contending theoretical accounts of such sex and age differences are considered and explanatory accounts that present a synthesis of endogenous and exogenous causal factors are discussed in light of the present pattern of findings. Copyright 2009 Elsevier B.V. All rights reserved.
A note on the graphical presentation of prediction intervals in random-effects meta-analyses.
Guddat, Charlotte; Grouven, Ulrich; Bender, Ralf; Skipka, Guido
2012-07-28
Meta-analysis is used to combine the results of several related studies. Two different models are generally applied: the fixed-effect (FE) and random-effects (RE) models. Although the two approaches estimate different parameters (that is, the true effect versus the expected value of the distribution of true effects) in practice, the graphical presentation of results is the same for both models. This means that in forest plots of RE meta-analyses, no estimate of the between-study variation is usually given graphically, even though it provides important information about the heterogeneity between the study effect sizes. In addition to the point estimate of the between-study variation, a prediction interval (PI) can be used to determine the degree of heterogeneity, as it provides a region in which about 95% of the true study effects are expected to be found. To distinguish between the confidence interval (CI) for the average effect and the PI, it may also be helpful to include the latter interval in forest plots. We propose a new graphical presentation of the PI; in our method, the summary statistics in forest plots of RE meta-analyses include an additional row, '95% prediction interval', and the PI itself is presented in the form of a rectangle below the usual diamond illustrating the estimated average effect and its CI. We then compare this new graphical presentation of PIs with previous proposals by other authors. The way the PI is presented in forest plots is crucial. In previous proposals, the distinction between the CI and the PI has not been made clear, as both intervals have been illustrated either by a diamond or by extra lines added to the diamond, which may result in misinterpretation. To distinguish graphically between the results of an FE and those of an RE meta-analysis, it is helpful to extend forest plots of the latter approach by including the PI. Clear presentation of the PI is necessary to avoid confusion with the CI of the average effect estimate.
Dynamic Bandwidth Allocation with Effective Utilization of Polling Interval over WDM/TDM PON
NASA Astrophysics Data System (ADS)
Ni, Cuiping; Gan, Chaoqin; Gao, Ziyue
2014-12-01
WDM/TDM (wavelength-division multiplexing/time-division multiplexing) PON (passive optical network) appears to be an attractive solution for the next generation optical access networks. Dynamic bandwidth allocation (DBA) plays a crucial role in efficiently and fairly allocating the bandwidth among all users in WDM/TDM PON. In this paper, two dynamic bandwidth allocation schemes (DBA1 and DBA2) are proposed to eliminate the idle time of polling cycles (i.e. polling interval), improve bandwidth utilization and make full use of bandwidth resources. The two DBA schemes adjust the time slot of sending request information and make fair scheduling among users to achieve the effective utilization of polling interval in WDM/TDM PON. The simulation and theoretical analyses verify that the proposed schemes outperform the conventional DBA scheme. We also make comparisons between the two schemes in terms of bandwidth utilization and average packet delay to further demonstrate the effectiveness of the scheme of DBA2.
Efird, Jimmy Thomas; Nielsen, Susan Searles
2008-12-01
Epidemiological studies commonly test multiple null hypotheses. In some situations it may be appropriate to account for multiplicity using statistical methodology rather than simply interpreting results with greater caution as the number of comparisons increases. Given the one-to-one relationship that exists between confidence intervals and hypothesis tests, we derive a method based upon the Hochberg step-up procedure to obtain multiplicity corrected confidence intervals (CI) for odds ratios (OR) and by analogy for other relative effect estimates. In contrast to previously published methods that explicitly assume knowledge of P values, this method only requires that relative effect estimates and corresponding CI be known for each comparison to obtain multiplicity corrected CI.
Grondin, Simon; Plourde, Marilyn
2007-10-01
This article discusses two experiments on the discrimination of time intervals presented in sequences marked by brief auditory signals. Participants had to indicate whether the last interval in a series of three intervals marked by four auditory signals was shorter or longer than the previous intervals. Three base durations were under investigation: 75, 150, and 225 ms. In Experiment 1, sounds were presented through headphones, from a single-speaker in front of the participants or by four equally spaced speakers. In all three presentation modes, the highest different threshold was obtained in the lower base duration condition (75 ms), thus indicating an impairment of temporal processing when sounds are presented too rapidly. The results also indicate the presence, in each presentation mode, of a 'time-shrinking effect' (i.e., with the last interval being perceived as briefer than the preceding ones) at 75 ms, but not at 225 ms. Lastly, using different sound sources to mark time did not significantly impair discrimination. In Experiment 2, three signals were presented from the same source, and the last signal was presented at one of two locations, either close or far. The perceived duration was not influenced by the location of the fourth signal when the participant knew before each trial where the sounds would be delivered. However, when the participant was uncertain as to its location, more space between markers resulted in longer perceived duration, a finding that applies only at 150 and 225 ms. Moreover, the perceived duration was affected by the direction of the sequences (left-right vs. right-left).
Scaling and memory effect in volatility return interval of the Chinese stock market
NASA Astrophysics Data System (ADS)
Qiu, T.; Guo, L.; Chen, G.
2008-12-01
We investigate the probability distribution of the volatility return intervals τ for the Chinese stock market. We rescale both the probability distribution Pq(τ) and the volatility return intervals τ as Pq(τ)=1/τbar f(τ/τbar ) to obtain a uniform scaling curve for different threshold value q. The scaling curve can be well fitted by the stretched exponential function f(x)∼e, which suggests memory exists in τ. To demonstrate the memory effect, we investigate the conditional probability distribution Pq(τ|τ0), the mean conditional interval <τ|τ0> and the cumulative probability distribution of the cluster size of τ. The results show clear clustering effect. We further investigate the persistence probability distribution P±(t) and find that P-(t) decays by a power law with the exponent far different from the value 0.5 for the random walk, which further confirms long memory exists in τ. The scaling and long memory effect of τ for the Chinese stock market are similar to those obtained from the United States and the Japanese financial markets.
Trynin, Alexandr Yu
2009-12-31
Classes of functions in the space of continuous functions f defined on the interval [0,{pi}] and vanishing at its end-points are described for which there is pointwise and approximate uniform convergence of Lagrange-type operators S{sub {lambda}}(f,x)={sigma}{sub k=0}{sup n} (y(x,{lambda}))/(y'(x{sub k,{lambda}})(x-x{sub k,{lambda}})) f(x{sub k,{lambda}}). These operators involve the solutions y(x,{lambda}) of the Cauchy problem for the equation y''+({lambda}-q{sub {lambda}}(x))y=0 where q{sub {lambda}} element of V{sub {rho}{sub {lambda}}}[0,{pi}] (here V{sub {rho}{sub {lambda}}}[0,{pi}] is the ball of radius {rho}{sub {lambda}}=o({radical}{lambda}/ln {lambda}) in the space of functions of bounded variation vanishing at the origin, and y(x{sub k,{lambda}})=0). Several modifications of this operator are proposed, which allow an arbitrary continuous function on [0,{pi}] to be approximated uniformly. Bibliography: 40 titles.
NASA Astrophysics Data System (ADS)
Trynin, Alexandr Yu
2009-12-01
Classes of functions in the space of continuous functions f defined on the interval \\lbrack 0,\\pi \\rbrack and vanishing at its end-points are described for which there is pointwise and approximate uniform convergence of Lagrange-type operators \\displaystyle S_\\lambda(f,x)=\\sum_{k=0}^n\\frac{y(x,\\lambda)}{y'(x_{k,\\lambda})(x-x_{k,\\lambda})}f(x_{k,\\lambda}). These operators involve the solutions y(x,\\lambda) of the Cauchy problem for the equation \\displaystyle y''+(\\lambda-q_\\lambda(x))y=0 where q_\\lambda\\in V_{\\rho_\\lambda} \\lbrack 0,\\pi \\rbrack (here V_{\\rho_\\lambda} \\lbrack 0,\\pi \\rbrack is the ball of radius \\rho_\\lambda=o(\\sqrt\\lambda/\\ln\\lambda) in the space of functions of bounded variation vanishing at the origin, and y(x_{k,\\lambda})=0). Several modifications of this operator are proposed, which allow an arbitrary continuous function on \\lbrack 0,\\pi \\rbrack to be approximated uniformly. Bibliography: 40 titles.
Modeling abundance effects in distance sampling
Royle, J. Andrew; Dawson, D.K.; Bates, S.
2004-01-01
Distance-sampling methods are commonly used in studies of animal populations to estimate population density. A common objective of such studies is to evaluate the relationship between abundance or density and covariates that describe animal habitat or other environmental influences. However, little attention has been focused on methods of modeling abundance covariate effects in conventional distance-sampling models. In this paper we propose a distance-sampling model that accommodates covariate effects on abundance. The model is based on specification of the distance-sampling likelihood at the level of the sample unit in terms of local abundance (for each sampling unit). This model is augmented with a Poisson regression model for local abundance that is parameterized in terms of available covariates. Maximum-likelihood estimation of detection and density parameters is based on the integrated likelihood, wherein local abundance is removed from the likelihood by integration. We provide an example using avian point-transect data of Ovenbirds (Seiurus aurocapillus) collected using a distance-sampling protocol and two measures of habitat structure (understory cover and basal area of overstory trees). The model yields a sensible description (positive effect of understory cover, negative effect on basal area) of the relationship between habitat and Ovenbird density that can be used to evaluate the effects of habitat management on Ovenbird populations.
He, Mingjun; Mu, Jianjun; Liu, Fuqiang; Ren, Keyu; Wang, Yang; Guo, Tongshuai; Wang, Dan
2015-01-01
To evaluate the effects of dietary sodium intake on QT interval dispersion (QTd) in normotensive healthy subjects and assess the protective effects of dietary potassium. Methods All subjects were sequentially maintained on a protocol with a three-day baseline investigation, seven-day low-salt period (3 g/day (d), NaCL), seven-day salt loading period (18 g/d, NaCL) and a seven-day salt loading with potassium supplementation period (4.5 g/d, KCL). On the last day of each period, 24-hour urine samples were collected, the blood pressure values were measured and an electrocardiogram was recorded. The QT interval, QTd and T peak-T end interval (Tp-Te) were subsequently measured and calculated. Patients Sixty-four normotensive subjects, men and women, ranging from 28 to 60 years of age, were enrolled. Results There were no great fluctuations in heart rate after salt loading, whereas the systolic blood pressure (SBP, mmHg) and diastolic blood pressure (DBP, mmHg) increased and the corrected QT interval (QTc), corrected QT interval dispersion (QTdc) and Tp-Te values were significantly prolonged compared to that observed in the low-salt period (SBP, 118.6 ± 13.5 vs. 111.7 ± 11.3, p<0.01; DBP, 76.9 ± 8.6 vs. 71.7 ± 7.7, p<0.01; QTdc, 60.3 ± 19.4 vs. 55.6 ± 19.4, p<0.05; Tp-Te, 83.0 ± 10.1 vs. 79.8 ± 8.5, p<0.01). Surprisingly, all of these changes were reversed by potassium supplementation (SBP, 114.5 ± 12.3 vs.118.6 ± 13.5, p<0.01; DBP, 72.2 ± 7.9 vs.76.9 ± 8.6, p<0.01;QTd, 42.6 ± 15.1 vs. 47.4 ± 19.0, p<0.05; QTdc, 52.2 ± 18.0 vs. 60.3 ± 19.4, p<0.05; Tp-Te, 79.1 ± 8.5 vs. 83.0 ± 10.1, p<0.01). Conclusion Salt loading prolongs the QT interval, QTd and Tp-Te, while dietary potassium supplementation reverses these alterations. These findings suggest that potassium supplementation may improve variation in the healing time and prevent arrhythmia.
Paquette, M; Le Blanc, O; Lucas, S J E; Thibault, G; Bailey, D M; Brassard, P
2017-03-01
We compared the effects of submaximal and supramaximal cycling interval training on determinants of exercise performance in moderately endurance-trained men. Maximal oxygen consumption (VO2max ), peak power output (Ppeak ), and peak and mean anaerobic power were measured before and after 6 weeks (3 sessions/week) of submaximal (85% maximal aerobic power [MP], HIIT85 , n = 8) or supramaximal (115% MP, HIIT115 , n = 9) interval training to exhaustion in moderately endurance-trained men. High-intensity training volume was 47% lower in HIIT115 vs HIIT85 (304 ± 77 vs 571 ± 200 min; P < 0.01). Exercise training was generally associated with increased VO2max (HIIT85 : +3.3 ± 3.1 mL/kg/min; HIIT115 : +3.3 ± 3.6 ml/kg/min; Time effect P = 0.002; Group effect: P = 0.95), Ppeak (HIIT85 : +18 ± 9 W; HIIT115 : +16 ± 27 W; Time effect P = 0.045; Group effect: P = 0.49), and mean anaerobic power (HIIT85 : +0.42 ± 0.69 W/kg; HIIT115 : +0.55 ± 0.65 W/kg; Time effect P = 0.01; Group effect: P = 0.18). Six weeks of submaximal and supramaximal interval training performed to exhaustion seems to equally improve VO2max and anaerobic power in endurance-trained men, despite half the accumulated time spent at the target intensity.
The effect of filtering and inter-digit interval on the recognition of dichotic digits.
Carter, A S; Wilson, R H
2000-01-01
The new compact disc from the Department of Veterans Affairs, Tonal and Speech Materials for Auditory, Perceptual Assessment, Disc 2.0 (1998), contains two lists of randomly interleaved 1-, 2-, and 3-pair dichotic digits. Two experiments are reported, in which the effects of low-pass filtering and inter-digit interval on dichotic digit recognition were investigated in adult listeners with normal hearing and with mild-to-moderate cochlear hearing loss. Results demonstrated that in the filtered condition, as the low-pass cutoff was increased, there was an increase in recognition performance for 1-, 2-, and 3-pair dichotic digits. When compared to normative data for the materials, findings indicate that the interleaved 1-, 2-, and 3-pair dichotic digit materials were essentially resistant to the effects of hearing loss. There was no significant change in recognition performance as a function of inter-digit interval. The studied 625-ms range of inter-digit intervals studied produced consistent recognition performance with both groups of listeners.
Meck, Warren H; Cheng, Ruey-Kuang; MacDonald, Christopher J; Gainetdinov, Raul R; Caron, Marc G; Cevik, Münire Özlem
2012-03-01
The dopamine transporter (DAT) is the major regulator of the spatial and temporal resolution of dopaminergic neurotransmission in the brain. Hyperdopaminergic mice with DAT gene deletions were evaluated for their ability to perform duration discriminations in the seconds-to-minutes range. DAT -/- mice were unable to demonstrate temporal control of behavior in either fixed-interval or peak-interval timing procedures, whereas DAT +/- mice were similar to DAT +/+ mice under normal conditions. Low to moderate-dose methamphetamine (MAP) challenges indicated that DAT +/- mice were less sensitive to the clock-speed enhancing effects of MAP compared with DAT +/+ mice. In contrast, DAT +/- mice were more vulnerable than DAT +/+ mice to the disruptive effects of MAP at high doses as revealed by the elevation of response rate in the right hand tail of the Gaussian-shaped timing functions. Moreover, this treatment made DAT +/- mice functionally equivalent to DAT -/- mice in terms of the loss of temporal control. Taken together, these results demonstrate the importance of dopaminergic control of interval timing in cortico-striatal circuits and the potential link of timing dysfunctions to schizophrenia and drug abuse. Copyright © 2011 Elsevier Ltd. All rights reserved.
Effects of the status of women on the first-birth interval in Indian urban society.
Nath, D C; Land, K C; Goswami, G
1999-01-01
The status of women, which is relative and multidimensional, has an important bearing on any long-term reduction in fertility. In Indian society, where cohabitation and childbearing are socially sanctioned only after marriage, the length of the first-birth interval affects the completed family size by influencing the spacing and childbearing pattern of a family. This study examines the influence of certain aspects of the status of married women--education, employment, role in family decision making, and age at marriage--along with three socioeconomic variables--per capita income of the family, social position of the household, and the caste system--on the duration of the first-birth interval in an urban Hindu society of the north-east Indian state of Assam. The data were analysed by applying life table and hazard regression techniques. The results indicate that a female's age at marriage, education, current age, role in decision making, and the per capita income of the household are the main covariates that strongly influence the length of the first-birth interval of Hindu females of urban Assam. Of all the covariates studied, a female's education appears to be a key mediating factor, through its influence on her probability of employment outside the home and thereby an earned income and on her role in family decision making. Unlike other Indian communities, the effect of the caste system does not have a significant effect on first-birth timing in this urban Hindu society.
[Effect of olopatadine hydrochloride, a novel antiallergic agent, on the QT interval in dogs].
Iwamoto, K; Ikeda, J; Nito, M; Kosaka, N; Ichikawa, S; Kobayashi, H; Ohmori, K
2001-06-01
Olopatadine hydrochloride (olopatadine), a novel antiallergic agent, is effective in the treatment of allergic rhinitis, chronic urticaria, eczema and dermatitis. It has been reported that terfenadine and astemizole cause side effects on the circulatory system such as QT prolongation followed by serious ventricular arrhythmias (torsades de pointes). To investigate the possibility of QT prolongation, we used both conscious normal dogs and hypokalemia-anesthetized dogs under two conditions: 1) olopatadine used alone and 2) olopatadine used in combination with itraconazole, the CYP3A4-inhibiting antifungal agent, in the present investigation. The group treated with terfenadine alone (30 mg/kg, p.o.) and the group treated with a combination of terfenadine (10 mg/kg, p.o.) and itraconazole (100 mg/kg, p.o.) had a significantly prolonged QT interval. On the other hand, the group treated with olopatadine alone (30 mg/kg, p.o.) and the group treated with a combination of olopatadine (30 mg/kg, p.o.) and itraconazole (100 mg/kg, p.o.) did not show any significant changes in QT interval. Moreover, olopatadine (1 and 5 mg/kg, i.v.) did not influence the QT interval in hypokalemia-anesthetized dogs. These results suggest that there is very little possibility of QT prolongation as a result of clinically used olopatadine.
Information Conversion, Effective Samples, and Parameter Size
Lin, Xiaodong; Pittman, Jennifer; Clarke, Bertrand
2008-01-01
Consider the relative entropy between a posterior density for a parameter given a sample and a second posterior density for the same parameter, based on a different model and a different data set. Then the relative entropy can be minimized over the second sample to get a virtual sample that would make the second posterior as close as possible to the first in an informational sense. If the first posterior is based on a dependent dataset and the second posterior uses an independence model, the effective inferential power of the dependent sample is transferred into the independent sample by the optimization. Examples of this optimization are presented for models with nuisance parameters, finite mixture models, and models for correlated data. Our approach is also used to choose the effective parameter size in a Bayesian hierarchical model. PMID:19079764
Higashijima, U; Terao, Y; Ichinomiya, T; Miura, K; Fukusaki, M; Sumikawa, K
2010-07-01
The aim of this study was to determine the effect of thiamylal and propofol on heart rate-corrected QT (QTc) interval during anaesthetic induction. We studied 50 patients undergoing lumbar spine surgery. Patients were administered 3 microgxkg(-1) fentanyl and were randomly allocated to receive 5 mgxkg(-1) thiamylal or 1.5 mgxkg(-1) propofol as an induction agent. Tracheal intubation was performed after vecuronium administration. Heart rate, mean arterial pressure, bispectral index score, and 12-lead electrocardiogram were recorded at the following time points: just before (T1) and 2 min after (T2) fentanyl administration; 2 min after anaesthetic administration (T3); 2.5 min after vecuronium injection (T4); and 2 min after intubation (T5). Thiamylal prolonged (p < 0.0001), but propofol shortened (p < 0.0001), the QTc interval.
Modeling circadian and sleep-homeostatic effects on short-term interval timing
Späti, Jakub; Aritake, Sayaka; Meyer, Andrea H.; Kitamura, Shingo; Hida, Akiko; Higuchi, Shigekazu; Moriguchi, Yoshiya; Mishima, Kazuo
2015-01-01
Short-term interval timing i.e., perception and action relating to durations in the seconds range, has been suggested to display time-of-day as well as wake dependent fluctuations due to circadian and sleep-homeostatic changes to the rate at which an underlying pacemaker emits pulses; pertinent human data being relatively sparse and lacking in consistency however, the phenomenon remains elusive and its mechanism poorly understood. To better characterize the putative circadian and sleep-homeostatic effects on interval timing and to assess the ability of a pacemaker-based mechanism to account for the data, we measured timing performance in eighteen young healthy male subjects across two epochs of sustained wakefulness of 38.67 h each, conducted prior to (under entrained conditions) and following (under free-running conditions) a 28 h sleep-wake schedule, using the methods of duration estimation and duration production on target intervals of 10 and 40 s. Our findings of opposing oscillatory time courses across both epochs of sustained wakefulness that combine with increasing and, respectively, decreasing, saturating exponential change for the tasks of estimation and production are consistent with the hypothesis that a pacemaker emitting pulses at a rate controlled by the circadian oscillator and increasing with time awake determines human short-term interval timing; the duration-specificity of this pattern is interpreted as reflecting challenges to maintaining stable attention to the task that progressively increase with stimulus magnitude and thereby moderate the effects of pacemaker-rate changes on overt behavior. PMID:25741253
Foster, Carl; Farland, Courtney V.; Guidotti, Flavia; Harbin, Michelle; Roberts, Brianna; Schuette, Jeff; Tuuri, Andrew; Doberstein, Scott T.; Porcari, John P.
2015-01-01
High intensity interval training (HIIT) has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement. This study compared the effects of two HIIT protocols vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training. Fifty-five untrained college-aged subjects were randomly assigned to three training groups (3x weekly). Steady-state (n = 19) exercised (cycle ergometer) 20 minutes at 90% of ventilatory threshold (VT). Tabata (n = 21) completed eight intervals of 20s at 170% VO2max/10s rest. Meyer (n = 15) completed 13 sets of 30s (20 min) @ 100% PVO2 max/ 60s recovery, average PO = 90% VT. Each subject did 24 training sessions during 8 weeks. Results: There were significant (p < 0.05) increases in VO2max (+19, +18 and +18%) and PPO (+17, +24 and +14%) for each training group, as well as significant increases in peak (+8, + 9 and +5%) & mean (+4, +7 and +6%) power during Wingate testing, but no significant differences between groups. Measures of the enjoyment of the training program indicated that the Tabata protocol was significantly less enjoyable (p < 0.05) than the steady state and Meyer protocols, and that the enjoyment of all protocols declined (p < 0.05) across the duration of the study. The results suggest that although HIIT protocols are time efficient, they are not superior to conventional exercise training in sedentary young adults. Key points Steady state training equivalent to HIIT in untrained students Mild interval training presents very similar physiologic challenge compared to steady state training HIIT (particularly very high intensity variants were less enjoyable than steady state or mild interval training Enjoyment of training decreases across the course of an 8 week experimental training program PMID:26664271
ERIC Educational Resources Information Center
Dignath, David; Pfister, Roland; Eder, Andreas B.; Kiesel, Andrea; Kunde, Wilfried
2014-01-01
We examined whether a temporal interval between an action and its sensory effect is integrated in the cognitive action structure in a bidirectional fashion. In 3 experiments, participants first experienced that actions produced specific acoustic effects (high and low tones) that occurred temporally delayed after their actions. In a following test…
ERIC Educational Resources Information Center
Dignath, David; Pfister, Roland; Eder, Andreas B.; Kiesel, Andrea; Kunde, Wilfried
2014-01-01
We examined whether a temporal interval between an action and its sensory effect is integrated in the cognitive action structure in a bidirectional fashion. In 3 experiments, participants first experienced that actions produced specific acoustic effects (high and low tones) that occurred temporally delayed after their actions. In a following test…
Berger, Barry M; Schroy, Paul C; Dinh, Tuan A
2016-09-01
A multitarget stool DNA (mt-sDNA) test was recently approved for colorectal cancer (CRC) screening for men and women, aged ≥ 50 years, at average risk of CRC. The guidelines currently recommend a 3-year interval for mt-sDNA testing in the absence of empirical data. We used clinical effectiveness modeling to project decreases in CRC incidence and related mortality associated with mt-sDNA screening to help inform interval setting. The Archimedes model (Archimedes Inc., San Francisco, CA) was used to conduct a 5-arm, virtual, clinical screening study of a population of 200,000 virtual individuals to compare the clinical effectiveness of mt-sDNA screening at 1-, 3-, and 5-year intervals compared with colonoscopy at 10-year intervals and no screening for a 30-year period. The study endpoints were the decrease in CRC incidence and related mortality of each strategy versus no screening. Cost-effectiveness ratios (US dollars per quality-adjusted life year [QALY]) of mt-sDNA intervals were calculated versus no screening. Compared with 10-year colonoscopy, annual mt-sDNA testing produced similar reductions in CRC incidence (65% vs. 63%) and related mortality (73% vs. 72%). mt-sDNA testing at 3-year intervals reduced the CRC incidence by 57% and CRC mortality by 67%, and mt-sDNA testing at 5-year intervals reduced the CRC incidence by 52% and CRC mortality by 62%. At an average price of $600 per test, the annual, 3-year, and 5-year mt-sDNA screening costs would be $20,178, $11,313, and $7388 per QALY, respectively, compared with no screening. These data suggest that screening every 3 years using a multitarget mt-sDNA test provides reasonable performance at acceptable cost. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
Effect of high-intensity interval exercise on basal triglyceride metabolism in non-obese men.
Bellou, Elena; Magkos, Faidon; Kouka, Tonia; Bouchalaki, Eirini; Sklaveniti, Dimitra; Maraki, Maria; Tsekouras, Yiannis E; Panagiotakos, Demosthenes B; Kavouras, Stavros A; Sidossis, Labros S
2013-08-01
A single bout of high-intensity interval aerobic exercise has been shown to produce the same or greater metabolic benefits as continuous endurance exercise with considerably less energy expenditure, but whether this applies to very low density lipoprotein (VLDL) metabolism is not known. We sought to examine the effect of a single bout of high-intensity interval aerobic exercise on basal VLDL-triglyceride (TG) kinetics 14 and 48 h after exercise cessation to determine the acute and time-dependent effects of this type of exercise on VLDL-TG metabolism. Eight healthy sedentary men (age, 23.6 ± 6.1 years; body mass index, 23.1 ± 2.2 kg·m(-2), peak oxygen consumption (V̇O2peak), 36.3 ± 5.5 mL·kg(-1)·min(-1)) participated in three stable isotopically labeled tracer infusion studies: (i) 14 h and (ii) 48 h after a single bout of high-intensity aerobic interval exercise (60% and 90% of V̇O2peak in 4 min intervals for a total of 32 min; gross energy expenditure ∼500 kcal) and (iii) after an equivalent period of rest, in random order. Fasting plasma VLDL-TG concentration was 20% lower at 14 h (P = 0.046) but not at 48 h (P = 1.000) after exercise compared with the resting trial. VLDL-TG plasma clearance rate increased by 21% at 14 h (P < 0.001) but not at 48 h (P = 0.299) after exercise compared with rest, whereas hepatic VLDL-TG secretion rate was not different from rest at any time point after exercise. We conclude that high-intensity interval exercise reduces fasting plasma VLDL-TG concentrations in non-obese men the next day by augmenting VLDL-TG clearance, just like a single bout of continuous endurance exercise. This effect is short-lived and abolished by 48 h after exercise.
ERIC Educational Resources Information Center
Berntzen, Dagfinn; Gotestam, K. Gunnar
1987-01-01
Compared the effects of fixed-interval and on-demand administration of analgesic medications in chronic pain patients. A fixed-interval analgesic schedule was found more effective than an on-demand schedule in reducing subjective pain and elevating mood. No differences were found between the two conditions on measures of physical activity.…
ERIC Educational Resources Information Center
Berntzen, Dagfinn; Gotestam, K. Gunnar
1987-01-01
Compared the effects of fixed-interval and on-demand administration of analgesic medications in chronic pain patients. A fixed-interval analgesic schedule was found more effective than an on-demand schedule in reducing subjective pain and elevating mood. No differences were found between the two conditions on measures of physical activity.…
Effect of sample inhomogeneity in KAr dating
Engels, J.C.; Ingamells, C.O.
1970-01-01
Error in K-Ar ages is often due more to deficiencies in the splitting process, whereby portions of the sample are taken for potassium and for argon determination, than to imprecision in the analytical methods. The effect of the grain size of a sample and of the composition of a contaminating mineral can be evaluated, and this provides a useful guide in attempts to minimize error. Rocks and minerals should be prepared for age determination with the effects of contaminants and grain size in mind. The magnitude of such effects can be much larger than intuitive estimates might indicate. ?? 1970.
Smith-Ryan, Abbie E.; Trexler, Eric T.; Wingfield, Hailee; Blue, Malia N.M.
2016-01-01
The purpose of this study was to evaluate two practical interval training protocols on cardiorespiratory fitness, lipids, and body composition in overweight/obese women. Thirty women (mean ± SD; Weight: 88.1 ± 15.9 kg; BMI: 32.0 ± 6.0 kg·m2) were randomly assigned to ten 1-minute high-intensity intervals (90%VO2peak, 1min recovery), or five 2-minute high-intensity intervals (80-100% VO2peak, 1 min recovery), or control. Peak oxygen uptake (VO2peak), peak power output, body composition, and fasting blood lipids were evaluated before and after 3 weeks of training, completed 3 days per week. Results from ANCOVA analyses demonstrated no significant training group differences for any primary variables (p>0.05). When training groups were collapsed, 1MIN and 2MIN resulted in a significant increase in peak power output (∆18.9 ± 8.5 watts; p=0.014) and time to exhaustion (∆55.1 ± 16.4 sec; p=0.001); non-significant increase in VO2peak (∆2.36 ± 1.34 ml·kg−1·min−1; p=0.185); and a significant decrease in fat mass (∆−1.96 ± 0.99kg; p=0.011). Short-term interval exercise training may be effective for decreasing fat mass and improving exercise tolerance in overweight and obese women. PMID:26934687
Effects on QTc Interval of 2 Different Doses of Spinal Anesthesia in Inguinal Hernia Operations
Hanbeyoglu, Onur; Urfalioglu, Aykut; Yazar, Fatih Mehmet; Ozcan, Sibel
2017-01-01
Background Cardiac arrhythmia is a significant cause of morbidity and mortality. In this study, through examination of the effects on the QTc interval of different doses of hyperbaric bupivacaine, we investigated the relationship with arrhythmia. Material/Methods A total of 60 patients were separated into 2 groups: spinal block was applied with 10 mg bupivacaine to Group S1 and with 15 mg to Group S2. The mean arterial pressure (MAP) and heart rate (HR) values were recorded before the spinal block and at 5 and 30 min after the block and at 60 min postoperatively. By recording the time of the spinal sensory block to reach T10 dermatome (Anaesth T) and the duration of the surgical procedure (Surg T.), the QTc intervals were calculated. Results The demographic data were similar in both groups. A statistically significant difference was determined between the S1 and S2 groups between the baseline and the 30 mins after spinal block QTc intervals (p=0.001). No statistically significant difference in HR values was determined between the groups at baseline, 5 min after spinal block, and 1 h after surgery (all p>0.05), but at 30 min after spinal block value there was a statistically significant difference (p=0.010). No statistically significant difference was determined in MAP values between the groups at baseline and 1 h after surgery (p>0.05). Conclusions The QTc interval lengthened in a dose-dependent manner after spinal anesthesia was applied with different doses of bupivacaine, but the doses used did not cause any severe arrhythmia. PMID:28285318
Sandoe, J A T; Patel, P A; Baig, M W; West, R
2013-11-01
Penicillin is an important treatment option for streptococcal infective endocarditis (IE), but its short half-life requires frequent re-dosing (4- or 6-hourly). There is a variation between the dosing regimens in different guidelines and consequent differences in the dosing interval. The objective of this study was to examine the relationship between the penicillin dosing interval and outcomes in streptococcal IE. A retrospective study of cases of streptococcal IE was undertaken using the Leeds Endocarditis Service database. Cases were included if the first-line therapy had been penicillin and excluded if patients had received less than 72 h of therapy. Details of antimicrobial therapy and outcomes were collated using strict definitions. Various parameters were considered as independent variables in a multivariate logistic regression analysis. Univariate analysis of categorical data was carried out using a χ(2) test, and analysis of continuous data using an unpaired t-test. Two hundred and twelve cases were included in the final analysis. Of the parameters considered, a 4-hourly dosing interval [unadjusted OR = 2.79 (95% CI 1.43-5.62)] and initial echocardiographic evidence of abscess or severe valve regurgitation [unadjusted OR = 0.30 (95% CI 0.13-0.66)] were the only statistically significant factors associated with the success or failure of penicillin therapy. The odds of a successful outcome were almost three times greater with a 4-hourly regimen than with a 6-hourly regimen. Failure of penicillin therapy had no correlation with the MIC of penicillin or the concurrent administration of gentamicin. Penicillin continues to be an effective therapy for IE. This study suggests that a 4-hourly dosing interval may be relevant in predicting the success of initial medical therapy. Further prospective studies are warranted to evaluate relationships in more detail.
Simulation of sampling effects in FPAs
NASA Astrophysics Data System (ADS)
Cook, Thomas H.; Hall, Charles S.; Smith, Frederick G.; Rogne, Timothy J.
1991-09-01
The use of multiplexers and large focal plane arrays in advanced thermal imaging systems has drawn renewed attention to sampling and aliasing issues in imaging applications. As evidenced by discussions in a recent workshop, there is no clear consensus among experts whether aliasing in sensor designs can be readily tolerated, or must be avoided at all cost. Further, there is no straightforward, analytical method that can answer the question, particularly when considering image interpreters as different as humans and autonomous target recognizers (ATR). However, the means exist for investigating sampling and aliasing issues through computer simulation. The U.S. Army Tank-Automotive Command (TACOM) Thermal Image Model (TTIM) provides realistic sensor imagery that can be evaluated by both human observers and TRs. This paper briefly describes the history and current status of TTIM, explains the simulation of FPA sampling effects, presents validation results of the FPA sensor model, and demonstrates the utility of TTIM for investigating sampling effects in imagery.
Sample design effects in landscape genetics
Oyler-McCance, Sara J.; Fedy, Bradley C.; Landguth, Erin L.
2012-01-01
An important research gap in landscape genetics is the impact of different field sampling designs on the ability to detect the effects of landscape pattern on gene flow. We evaluated how five different sampling regimes (random, linear, systematic, cluster, and single study site) affected the probability of correctly identifying the generating landscape process of population structure. Sampling regimes were chosen to represent a suite of designs common in field studies. We used genetic data generated from a spatially-explicit, individual-based program and simulated gene flow in a continuous population across a landscape with gradual spatial changes in resistance to movement. Additionally, we evaluated the sampling regimes using realistic and obtainable number of loci (10 and 20), number of alleles per locus (5 and 10), number of individuals sampled (10-300), and generational time after the landscape was introduced (20 and 400). For a simulated continuously distributed species, we found that random, linear, and systematic sampling regimes performed well with high sample sizes (>200), levels of polymorphism (10 alleles per locus), and number of molecular markers (20). The cluster and single study site sampling regimes were not able to correctly identify the generating process under any conditions and thus, are not advisable strategies for scenarios similar to our simulations. Our research emphasizes the importance of sampling data at ecologically appropriate spatial and temporal scales and suggests careful consideration for sampling near landscape components that are likely to most influence the genetic structure of the species. In addition, simulating sampling designs a priori could help guide filed data collection efforts.
Jentzsch, Ines; Leuthold, Hartmut
2005-08-01
In serial choice reaction time (RT) tasks, performance in each trial critically depends on the sequence of preceding events. In this study, the authors specifically examined the mechanism underlying RT sequence effects at short response-stimulus intervals (RSIs), in which performance is impaired in the current trial N if events alternate rather than repeat from trial N-2 to trial N-1. Different accounts of this RT pattern in terms of perceptual noise, response-selection monitoring, and response conflict were tested in 4 experiments. Second-order RT costs were caused by the response sequence rather than the stimulus sequence. Manipulation of stimulus contrast, stimulus classification difficulty, and set-level compatibility did not modulate the response-related second-order RT effect, whereas this effect increased when spatially incompatible responses were demanded. These findings support a response conflict account of higher order sequential effects in short-RSI situations.
Hall, Ashley; Ballantyne, Jack
2003-09-09
For a variety of reasons, some victims of sexual assault provide vaginal samples more than 24-36 h after the incident. In these cases, the ability to obtain an autosomal STR profile of the semen donor from the living victim diminishes rapidly as the post-coital interval is extended. We have used a number of carefully selected Y-STR loci in a variety of multiplex or monoplex formats to extend the post-coital interval from which a genetic profile of the semen donor can be obtained. The proposed Y-STR typing strategies enable the routine detection of the male donor Y-STR haplotype in cervicovaginal samples recovered up to 4 days post-coitus. We attribute our success to a number of factors that significantly improve the sensitivity and specificity of the analysis. Firstly, we utilize a subset of Y-STR loci that have been carefully selected for their superior performance under stressed conditions in both multiplex and monoplex formats. Specifically these loci function with low copy number templates in the presence of a vast excess of potentially confounding female DNA. Secondly, sperm and non-sperm DNA is co-extracted without a differential extraction process to prevent the unnecessary loss of the small number of structurally fragile sperm remaining in the cervicovaginal tract several days after intercourse. Thirdly, low copy number detection is facilitated by increasing the cycle number to 34-35 cycles and by the ability to input up to 450 ng of co-extracted sperm/non-sperm DNA into the PCR reaction without the appearance of confounding female artifacts. Lastly, the proper collection of post-coital cervicovaginal samples, instead of the lower or mid-vaginal tract samples often taken, is required for optimal recovery of sperm for analysis. In this report we demonstrate that our previously described 19 Y-STR loci systems (MPI and MPII) permit a reliable high resolution haplotype determination of the semen donor in cervicovaginal samples taken up to 48 h after intercourse
Scale and Sampling Effects on Floristic Quality
2016-01-01
Floristic Quality Assessment (FQA) is increasingly influential for making land management decisions, for directing conservation policy, and for research. But, the basic ecological properties and limitations of its metrics are ill defined and not well understood–especially those related to sample methods and scale. Nested plot data from a remnant tallgrass prairie sampled annually over a 12-year period, were used to investigate FQA properties associated with species detection rates, species misidentification rates, sample year, and sample grain/area. Plot size had no apparent effect on Mean C (an area’s average Floristic Quality level), nor did species detection levels above 65% detection. Simulated species misidentifications only affected Mean C values at greater than 10% in large plots, when the replaced species were randomly drawn from the broader county-wide species pool. Finally, FQA values were stable over the 12-year study, meaning that there was no evidence that the metrics exhibit year effects. The FQA metric Mean C is demonstrated to be robust to varied sample methodologies related to sample intensity (plot size, species detection rate), as well as sample year. These results will make FQA measures even more appealing for informing land-use decisions, policy, and research for two reasons: 1) The sampling effort needed to generate accurate and consistent site assessments with FQA measures is shown to be far lower than what has previously been assumed, and 2) the stable properties and consistent performance of metrics with respect to sample methods will allow for a remarkable level of comparability of FQA values from different sites and datasets compared to other commonly used ecological metrics. PMID:27489959
Scale and Sampling Effects on Floristic Quality.
Spyreas, Greg
2016-01-01
Floristic Quality Assessment (FQA) is increasingly influential for making land management decisions, for directing conservation policy, and for research. But, the basic ecological properties and limitations of its metrics are ill defined and not well understood-especially those related to sample methods and scale. Nested plot data from a remnant tallgrass prairie sampled annually over a 12-year period, were used to investigate FQA properties associated with species detection rates, species misidentification rates, sample year, and sample grain/area. Plot size had no apparent effect on Mean C (an area's average Floristic Quality level), nor did species detection levels above 65% detection. Simulated species misidentifications only affected Mean C values at greater than 10% in large plots, when the replaced species were randomly drawn from the broader county-wide species pool. Finally, FQA values were stable over the 12-year study, meaning that there was no evidence that the metrics exhibit year effects. The FQA metric Mean C is demonstrated to be robust to varied sample methodologies related to sample intensity (plot size, species detection rate), as well as sample year. These results will make FQA measures even more appealing for informing land-use decisions, policy, and research for two reasons: 1) The sampling effort needed to generate accurate and consistent site assessments with FQA measures is shown to be far lower than what has previously been assumed, and 2) the stable properties and consistent performance of metrics with respect to sample methods will allow for a remarkable level of comparability of FQA values from different sites and datasets compared to other commonly used ecological metrics.
Masson, Gustavo Santos; Borges, Juliana Pereira; da Silva, Pedro Paulo Soares; da Nóbrega, Antônio Cláudio Lucas; Tibiriçá, Eduardo; Lessa, Marcos Adriano
2016-05-01
The ability of continuous aerobic exercise training (AET) to increase baroreflex control and cardiac function in heart failure (HF) has been well described, but the comparison between continuous and interval AET on these functions is inconclusive. To compare the effects of continuous and interval AET on cardiac function and baroreflex sensitivity (BrS) in an experimental model of HF. Rats were divided into the following groups: continuous training (HF-CT), intense interval training (HF-IIT), moderate interval training (HF-MIT), sedentary group (HF-SED), and sham sedentary (SHAM-SED). Animals underwent surgery to induce HF by ligation of the interventricular coronary artery. Six weeks after surgery, AET was started (8weeks, 3sessions/week). Echocardiography studies to assess cardiac function were performed before and after AET. At the end of the training protocols, the BrS index was assessed by stepwise intravenous infusions of sodium nitroprusside and phenylephrine. All methods of exercise prevented the HF-induced increase in left ventricular diameter in diastole observed in the HF-SED rats (0.88±0.09 vs. 1.03±0.09cm; P<0.05), but only the HF-CT (28.5±6.3 vs. 39.2±12.7%; P<0.05) and HF-MIT (31.0±8.5 vs. 42.0±10.3%; P<0.05) groups exhibited an increase in ejection fraction. Nevertheless, the HF-CT group was the only group that showed a tachycardia reflex higher than that of the HF-SED group (0.87±0.34 vs. 0.20±0.05bpm/mmHg; P<0.05) and similar to that of the SHAM-SED group (1.04±0.11bpm/mmHg). These results suggest that continuous and moderate interval training induced similar improvements in cardiac function but that only continuous training induced higher BrS in HF rats. Copyright © 2016 Elsevier B.V. All rights reserved.
Oral Contraceptive Use and the ECG: Evidence of an Adverse QT Effect on Corrected QT Interval
Sedlak, Tara; Shufelt, Chrisandra; Iribarren, Carlos; Lyon, Liisa L; Merz, C. Noel Bairey
2013-01-01
Background A prolonged corrected QT (QTc) interval is a marker for an increased risk of sudden cardiac death. We evaluated the relationship between oral contraceptive (OC) use, type of OC, and QTc interval. Methods We identified 410,782 ECGs performed at Northern California Kaiser Permanente on female patients between 15–53 years from January, 1995 to June, 2008. QT was corrected for heart rate using log-linear regression. OC generation (first, second and third) was classified by increasing progestin androgenic potency, while the fourth generation was classified as anti-androgenic. Results Among 410,782 women, 8.4% were on OC. In multivariate analysis after correction for comorbidities, there was an independent shortening effect of OCs overall (slope = −0.5ms; SE = 0.12, p<0.0002). Users of first and second generation progestins had a significantly shorter QTc than non-users (p<0.0001), while users of fourth generation had a significantly longer QTc than non-users (slope = 3.6ms, SE = 0.35, p<0.0001). Conclusion Overall, OC use has a shortening effect on the QTc. Shorter QTc is seen with first and second generation OC while fourth generation OC use has a lengthening effect on the QTc. Careful examination of adverse event rates in fourth generation OC users is needed. PMID:23879279
BootES: an R package for bootstrap confidence intervals on effect sizes.
Kirby, Kris N; Gerlanc, Daniel
2013-12-01
Bootstrap Effect Sizes (bootES; Gerlanc & Kirby, 2012) is a free, open-source software package for R (R Development Core Team, 2012), which is a language and environment for statistical computing. BootES computes both unstandardized and standardized effect sizes (such as Cohen's d, Hedges's g, and Pearson's r) and makes easily available for the first time the computation of their bootstrap confidence intervals (CIs). In this article, we illustrate how to use bootES to find effect sizes for contrasts in between-subjects, within-subjects, and mixed factorial designs and to find bootstrap CIs for correlations and differences between correlations. An appendix gives a brief introduction to R that will allow readers to use bootES without having prior knowledge of R.
Salient stimuli in advertising: the effect of contrast interval length and type on recall.
Olsen, G Douglas
2002-09-01
Salient auditory stimuli (e.g., music or sound effects) are commonly used in advertising to elicit attention. However, issues related to the effectiveness of such stimuli are not well understood. This research examines the ability of a salient auditory stimulus, in the form of a contrast interval (CI), to enhance recall of message-related information. Researchers have argued that the effectiveness of the CI is a function of the temporal duration between the onset and offset of the change in the background stimulus and the nature of this stimulus. Three experiments investigate these propositions and indicate that recall is enhanced, providing the CI is 3 s or less. Information highlighted with silence is recalled better than information highlighted with music.
Effects of memory age and interval of fear extinction sessions on contextual fear extinction.
Matsuda, Shingo; Matsuzawa, Daisuke; Ishii, Daisuke; Tomizawa, Haruna; Shimizu, Eiji
2014-08-22
Fear extinction is a major task in our understanding of the biological mechanisms of exposure therapy, one of the most used treatments for stress-related disorders. It was recently reported that an extinction of 5 consecutive days prevents spontaneous recovery of fear memory. Memory age and the timing of fear extinction influence the effect of fear extinction. In this study, we used contextual fear extinction in adult male mice to examine whether memory age influences an extinction of 5 consecutive days and whether consecutiveness is necessary to prevent spontaneous recovery. Our results showed that, although fear memory was not affected by the passage of time, the old fear memory (28 days after fear conditioning) was more sensitive to fear extinction than the young fear memory (7 days after fear conditioning). Additionally, we demonstrated that consecutiveness of extinction sessions is not necessary to prevent spontaneous recovery. Instead, fear extinction sessions at spaced intervals were found to be more effective than consecutive extinction sessions for young fear memory. Our results suggest that taking memory age and the interval of fear extinction sessions into consideration would help to optimize exposure therapy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Holloway, Owen G.; Waddell, Jonathan P.
2008-01-01
A borehole straddle packer was developed and tested by the U.S. Geological Survey to characterize the vertical distribution of contaminants, head, and hydraulic properties in open-borehole wells as part of an ongoing investigation of ground-water contamination at U.S. Air Force Plant 6 (AFP6) in Marietta, Georgia. To better understand contaminant fate and transport in a crystalline bedrock setting and to support remedial activities at AFP6, numerous wells have been constructed that include long open-hole intervals in the crystalline bedrock. These wells can include several discontinuities that produce water, which may contain contaminants. Because of the complexity of ground-water flow and contaminant movement in the crystalline bedrock, it is important to characterize the hydraulic and water-quality characteristics of discrete intervals in these wells. The straddle packer facilitates ground-water sampling and hydraulic testing of discrete intervals, and delivery of fluids including tracer suites and remedial agents into these discontinuities. The straddle packer consists of two inflatable packers, a dual-pump system, a pressure-sensing system, and an aqueous injection system. Tests were conducted to assess the accuracy of the pressure-sensing systems, and water samples were collected for analysis of volatile organic compound (VOCs) concentrations. Pressure-transducer readings matched computed water-column height, with a coefficient of determination of greater than 0.99. The straddle packer incorporates both an air-driven piston pump and a variable-frequency, electronic, submersible pump. Only slight differences were observed between VOC concentrations in samples collected using the two different types of sampling pumps during two sampling events in July and August 2005. A test conducted to assess the effect of stagnation on VOC concentrations in water trapped in the system's pump-tubing reel showed that concentrations were not affected. A comparison was conducted
Ercoşkun, Hüdayi; Taği, Seref; Ertaş, Ahmet Hamdi
2010-05-01
Fermentation time has an influence on the quality characteristics of fermented meat products. The effect of heat treatment on physicochemical, sensory and microbiological properties of sucuk was determined during fermentation and after heat application, and the properties of heat-treated sucuk samples were compared with those of traditional sucuk. Optimum fermentation period was determined for sucuk samples with desirable characteristics. Heat-treated sucuks were fermented at different fermentation intervals (0, 1, 2, 3, 4 and 5 days). Nine days of fermentation was included for traditional sucuks. All process parameters were applied under industrial conditions. Heat treatment increased the pH values, dry matter contents (protein, fat and salt), thiobarbituric acid reactive substances of sucuks while decreasing the moisture content, free fatty acidity, and all bacterial counts (total viable and lactic acid bacteria, Staphylococcus/Micrococcus and Enterobacteriaceae) (P<0.05). Significant differences in the instrumental color properties of heat-treated and traditional sucuk were found (P<0.05). In terms of physicochemical, sensory and microbial properties, fermentation for three or more days before heat treatment resulted in sucuk samples with better acceptability, and produced sucuk samples with quality characteristics similar to those of traditional sucuks.
DaVanzo, J; Hale, L; Razzaque, A; Rahman, M
2007-09-01
To estimate the effects on pregnancy outcomes of the duration of the preceding interpregnancy interval (IPI) and type of pregnancy outcome that began the interval. Observational population-based study. The Maternal Child Health-Family Planning (MCH-FP) area of Matlab, Bangladesh. A total of 66,759 pregnancy outcomes that occurred between 1982 and 2002. Bivariate tabulations and multinomial logistic regression analysis. Pregnancy outcomes (live birth, stillbirth, miscarriage [spontaneous fetal loss prior to 28 weeks], and induced abortion). When socio-economic and demographic covariates are controlled, of the IPIs that began with a live birth, those < 6 months in duration were associated with a 7.5-fold increase in the odds of an induced abortion (95% CI 6.0-9.4), a 3.3-fold increase in the odds of a miscarriage (95% CI 2.8-3.9), and a 1.6-fold increase in the odds of a stillbirth (95% CI 1.2-2.1) compared with 27- to 50-month IPIs. IPIs of 6-14 months were associated with increased odds of induced abortion (2.0, 95% CI 1.5-2.6). IPIs > or = 75 months were associated with increased odds of all three types of non-live-birth (NLB) outcomes but were not as risky as very short intervals. IPIs that began with a NLB were generally more likely to end with the same type of NLB. Women whose pregnancies are between 15 and 75 months after a preceding pregnancy outcome (regardless of its type) have a lower likelihood of fetal loss than those with shorter or longer IPIs. Those with a preceding NLB outcome deserve special attention in counselling and monitoring.
Effects of high-intensity interval training on the VO2 response during severe exercise.
Duffield, Rob; Edge, Johann; Bishop, David
2006-06-01
This study examined the effect of high-intensity interval training on the VO2 response during severe, constant-load exercise. Prior to, and following training, 10 females (V O2 peak 37.4+/-6.0 mL kg-1 min-1) performed a graded exercise test to determine VO2 peak and lactate threshold (LT) and a 6 min cycle test (CT) at the pre-training VO2 peak intensity. Training involved high-intensity intervals (2 min work, 1 min rest) performed 3x week for 8 weeks. Breath-by-breath data from 0 to 6 min during the CT were smoothed using 5s averages and fit to a bi-exponential model starting from 20s. Training resulted in significant improvements in VO2 max (2.34+/-0.37-2.78+/-0.30 L min-1), power at VO2 max (170+/-26-204+/-25 W) and power at LT (113+/-17-136+/-20 W) (p<0.05). Following training, the VO2 response showed a significant increase in the amplitude of the primary phase (A1) (1396+/-103-1695+/-100 mL min-1; p<0.05) and end-exercise VO2 (VO2 EE), with no difference (p>0.05) in the time constants of either phase or the amplitude of the slow component (318+/-67-380+/-48 mL; p=0.15). In conjunction, accumulated oxygen deficit (AOD) (43.7+/-9.8-17.2+/-2.8 mL O2 eq kg-1) and anaerobic contribution to the CT (19.4+/-4.4-7.2+/-1.2%) were significantly reduced. In contrast to previous moderate-intensity research, a high-intensity interval training program increased A1 and VO2 EE for the same absolute exercise intensity, decreasing the AOD during a severe-intensity CT.
The Effects of Interval Duration on Temporal Tracking and Alternation Learning
ERIC Educational Resources Information Center
Ludvig, Elliot A.; Staddon, John E. R.
2005-01-01
On cyclic-interval reinforcement schedules, animals typically show a postreinforcement pause that is a function of the immediately preceding time interval ("temporal tracking"). Animals, however, do not track single-alternation schedules--when two different intervals are presented in strict alternation on successive trials. In this experiment,…
The Effects of Interval Duration on Temporal Tracking and Alternation Learning
ERIC Educational Resources Information Center
Ludvig, Elliot A.; Staddon, John E. R.
2005-01-01
On cyclic-interval reinforcement schedules, animals typically show a postreinforcement pause that is a function of the immediately preceding time interval ("temporal tracking"). Animals, however, do not track single-alternation schedules--when two different intervals are presented in strict alternation on successive trials. In this experiment,…
The effect of filled and empty intervals on clock and memory processes in pigeons.
Price, Elizabeth; Santi, Angelo
2014-06-01
According to the mixed memory model (Penney, Gibbon, & Meck, Journal of Experimental Psychology: Human Perception and Performance, 26, 1770-1787, 2000), different clock rates for stimuli with different nontemporal properties must be stored within a single reference memory distribution in order to detect a difference between the clock rates of the different signals. In Experiment 1, pigeons were trained in a between-subjects design to discriminate empty intervals (bound by two 1-s visual markers) and filled intervals (a continuous visual signal). The intervals were signaled by different visual stimuli, and they required responses to different sets of comparison stimuli. Empty intervals were judged as being longer than filled intervals. The difference between the point of subjective equality (PSE) for the empty intervals and the PSE for the filled intervals increased proportionally as the magnitudes of the anchor duration pairs were increased from 2 and 8 s to 4 and 16 s. In Experiment 2, the pigeons were trained to discriminate intervals signaled by the absence of houselight illumination (Group Empty) or the presence of houselight illumination (Group Filled). The psychophysical timing functions for these intervals were identical to each other. The results of Experiment 1 indicate that memory mixing is not necessary for detecting a timing difference between empty and filled intervals in pigeons. The results of Experiment 2 suggest that the nature of the stimuli that signal the empty and filled intervals impacts how pigeons judge the durations of empty and filled intervals.
Ebach, Sarah C; Ramsthaler, Frank; Birngruber, Christoph G; Verhoff, Marcel A
2011-01-01
In this serial experiment, five human bones with known post-mortem intervals (PMI) in a soil environment from five different epochs (0.2 to approximately 2000 years) were tested in a blind setup with two established rapid tests for the identification of human blood traces (Hexagon-OBTI test and RSID blood test). Based on previous study results concerning the usability of the Luminol test for the first assessment of the PMI of osseous remains, the question arising was whether those test procedures, which are highly sensitive for the detection of human blood components, could also be used to narrow down the post-mortem interval. Five test series were conducted applying modified standard protocols of the manufactures. The aim was to find out whether with prior reaction steps or a prolonged time of incubation hemoglobin or its metabolites can be dissolved from the bone and positive test results can be achieved dependent on the PMI. Four test series yielded negative results for all bone samples and one test series a uniformly weak positive result. The results indicate that rapid tests based on the detection of blood are not suitable for the determination of the PMI of bone samples despite the modification of the standard protocols. Further thorough research is required to clarify the postmortem degradation of hemoglobin in bones.
Platiša, Mirjana M; Gal, Vera; Nestorović, Zorica; Gojković-Bukarica, Ljiljana
2014-10-01
The measures of nonlinear properties of RR interval and QT interval time series are sensitive to physiologically- or pathologically-induced complexity/regularity changes, but were not used to estimate the effect of alcohol intake. We wanted to examine the potential of these measures to quantify the acute effect of a low dose of red wine in healthy subjects. In separate experiments, fourteen young volunteers drank 200ml of red wine and a control drink with equal concentration of ethanol. ECG in supine position was recorded 20min before and 60min after drink intake. RR interval and QT interval series were extracted from ECG and we calculated variability, scaling exponents (α1 and α2) and sample entropy (SampEn) for both series. Systolic and diastolic blood pressures (BP) were measured every 10min. The immediate effect of both the drinks was equal: HR, BP and QT variability exhibited a sudden increase and then a decrease. However, the prolonged effect of wine and the control drink was different. Wine decreased both BP (p<0.05) and reduced complexity of RR and QT series (increased scaling exponents and decreased SampEn). The control drink prolonged QT and RR intervals (p<0.05). These results point out that the nonlinear properties of RR and QT interval series could be used to differentiate the effect of wine and ethanol. Changes in RR and QT interval series induced by a low dose of red wine are more detectable by methods that quantify the structure of the series than by methods that quantify their variability. Copyright © 2014 Elsevier Ltd. All rights reserved.
Salutary effects of high-intensity interval training in persons with elevated cardiovascular risk
Fleg, Jerome L.
2016-01-01
Although moderate-intensity continuous training (MICT) has been the traditional model for aerobic exercise training for over four decades, a growing body of literature has demonstrated equal if not greater improvement in aerobic capacity and similar beneficial effects on body composition, glucose metabolism, blood pressure, and quality of life from high-intensity interval training (HIIT). An advantage of HIIT over MICT is the shorter time required to perform the same amount of energy expenditure. The current brief review summarizes the effects of HIIT on peak aerobic capacity and cardiovascular risk factors in healthy adults and those with various cardiovascular diseases, including coronary artery disease, chronic heart failure, and post heart transplantation. PMID:27635241
Effect of Stochastic Modulation of Inter-Pulse Interval During Stimulated Isokinetic Leg Extension
Aksöz, Efe Anil; Laubacher, Marco; Binder-Macleod, Stuart; Hunt, Kenneth J.
2016-01-01
Recumbent cycling exercise achieved by functional electrical stimulation (FES) of the paralyzed leg muscles is effective for cardiopulmonary and musculoskeletal conditioning after spinal cord injury, but its full potential has not yet been realized. Mechanical power output and efficiency is very low and endurance is limited due to early onset of muscle fatigue. The aim of this work was to compare stochastic modulation of the inter-pulse interval (IPI) to constant-frequency stimulation during an isokinetic leg extension task similar to FES-cycling. Seven able-bodied subjects participated: both quadriceps muscles were stimulated (n = 14) with two activation patterns (P1-constant frequency, P2-stochastic IPI). There was significantly higher power output with P2 during the first 30 s (p = 0.0092), the last 30 s (p = 0.018) and overall (p = 0.0057), but there was no overall effect on fatiguability when stimulation frequency was randomly modulated. PMID:27990242
Effects of slow coronary artery flow on QT interval duration and dispersion.
Atak, Ramazan; Turhan, Hasan; Sezgin, Alpay T; Yetkin, Ozkan; Senen, Kubilay; Ileri, Mehmet; Sahin, Onur; Karabal, Orhan; Yetkin, Ertan; Kutuk, Emine; Demirkan, Deniz
2003-04-01
The coronary slow-flow phenomenon is an angiographic phenomenon characterized by delayed opacification of vessels in the absence of any evidence of obstructive epicardial coronary disease. Several studies have demonstrated myocardial ischemia in patients with slow coronary artery flow. In the present study, we aimed at evaluating the effects of slow coronary artery flow on QT interval duration and QT dispersion as a possible indicator of increased risk for ventricular arrhythmias and sudden cardiac death. The study population included 49 patients with angiographically proven normal coronary arteries and slow coronary flow in all three coronary vessels (group I, 33 males, 16 females, mean age = 48 +/- 9 years), and 71 patients with angiographically proven normal coronary arteries without associated slow coronary flow (group II, 47 males, 24 females, mean age = 50 +/- 8 years). Coronary flow rates of all subjects were documented by thrombolysis in myocardial infarction frame count (TIMI frame count). QT interval duration and QT dispersion of all subjects were measured on the standard 12-lead electrocardiogram. There was no statistically significant difference between the two groups in respect to age, gender, presence of hypertension, and diabetes mellitus. There was a significant difference between the two groups in respect to the presence of cigarette smoking, typical angina, and positive exercise test results. TIMI frame counts of group I patients were significantly higher than those of group II patients for all three coronary arteries (P < 0.001). Maximum corrected QT interval (QTcmax) of group I did not differ from the QTcmax of group II (P > 0.05). However, minimum corrected QT interval (QTcmin) of group I was significantly lower than that for group II (P = 0.008). Consequently, corrected QT dispersion (QTcd) in group I was found to be significantly higher than in group II (P < 0.001). QTcd, indicating increased risk for ventricular arrhythmias and
Effects of Rest Interval Length on Acute Battling Rope Exercise Metabolism.
Ratamess, Nicholas A; Smith, Charles R; Beller, Noah A; Kang, Jie; Faigenbaum, Avery D; Bush, Jill A
2015-09-01
The purpose of this study was to quantify and compare the acute metabolic responses to battling rope (BR) exercise using 2 different rest intervals. Twelve men and 10 women (age = 20.8 ± 1.3 years) performed a control protocol and 2 BR exercise protocols on separate days (48-72 hours) in random order while connected to a metabolic system. The BR protocol consisted of 8 sets of 30-second intervals (15 seconds of single-arm waves and 15 seconds of double-arm waves) using either a 1-minute (1RI) or 2-minute (2RI) rest interval length. A metronome was used to standardize repetition number/frequency for each exercise, that is, 15 waves for each arm for single-arm waves and 15 repetitions of double-arm waves. The mean oxygen consumption (VO2) values for the entire protocol were significantly higher during the 1RI than 2RI protocol, and values in men were 11.1% (1RI) and 13.5% (2RI) higher than women, respectively, and equated to 52.8 ± 5.5% (men) and 50.0 ± 11.2% (women) of VO2max during 1RI and 40.5 ± 4.5% (men) and 37.7 ± 11.0% (women) of VO2max during 2RI. Energy expenditure values were significantly higher during the 1RI than the 2RI protocol in men (11.93 ± 1.4 vs. 8.78 ± 1.4 kcal·min) and women (7.69 ± 1.3 vs. 5.04 ± 1.7 kcal·min) with values in men statistically higher than women. Blood lactate, mean protocol minute ventilation, and heart rate were significantly higher during the 1RI protocol than the 2RI protocol, and these data were significantly higher in men compared with women. These data demonstrate that BR exercise poses a significant cardiovascular and metabolic stimulus with the mean effects augmented with the use of a short rest interval.
The role of concentration−effect relationships in the assessment of QTc interval prolongation
France, Nicholas P; Della Pasqua, Oscar
2015-01-01
Population pharmacokinetic and pharmacokinetic−pharmacodynamic (PKPD) modelling has been widely used in clinical research. Yet, its application in the evaluation of cardiovascular safety remains limited, particularly in the evaluation of pro-arrhythmic effects. Here we discuss the advantages of disadvantages of population PKPD modelling and simulation, a paradigm built around the knowledge of the concentration−effect relationship as the basis for decision making in drug development and its utility as a guide to drug safety. A wide-ranging review of the literature was performed on the experimental protocols currently used to characterize the potential for QT interval prolongation, both pre-clinically and clinically. Focus was given to the role of modelling and simulation for design optimization and subsequent analysis and interpretation of the data, discriminating drug from system specific properties. Cardiovascular safety remains one of the major sources of attrition in drug development with stringent regulatory requirements. However, despite the myriad of tests, data are not integrated systematically to ensure accurate translation of the observed drug effects in clinically relevant conditions. The thorough QT study addresses a critical regulatory question but does not necessarily reflect knowledge of the underlying pharmacology and has limitations in its ability to address fundamental clinical questions. It is also prone to issues of multiplicity. Population approaches offer a paradigm for the evaluation of drug safety built around the knowledge of the concentration−effect relationship. It enables quantitative assessment of the probability of QTc interval prolongation in patients, providing better guidance to regulatory labelling and understanding of benefit/risk in specific populations. PMID:24938719
The role of concentration-effect relationships in the assessment of QTc interval prolongation.
France, Nicholas P; Della Pasqua, Oscar
2015-01-01
Population pharmacokinetic and pharmacokinetic-pharmacodynamic (PKPD) modelling has been widely used in clinical research. Yet, its application in the evaluation of cardiovascular safety remains limited, particularly in the evaluation of pro-arrhythmic effects. Here we discuss the advantages of disadvantages of population PKPD modelling and simulation, a paradigm built around the knowledge of the concentration-effect relationship as the basis for decision making in drug development and its utility as a guide to drug safety. A wide-ranging review of the literature was performed on the experimental protocols currently used to characterize the potential for QT interval prolongation, both pre-clinically and clinically. Focus was given to the role of modelling and simulation for design optimization and subsequent analysis and interpretation of the data, discriminating drug from system specific properties. Cardiovascular safety remains one of the major sources of attrition in drug development with stringent regulatory requirements. However, despite the myriad of tests, data are not integrated systematically to ensure accurate translation of the observed drug effects in clinically relevant conditions. The thorough QT study addresses a critical regulatory question but does not necessarily reflect knowledge of the underlying pharmacology and has limitations in its ability to address fundamental clinical questions. It is also prone to issues of multiplicity. Population approaches offer a paradigm for the evaluation of drug safety built around the knowledge of the concentration-effect relationship. It enables quantitative assessment of the probability of QTc interval prolongation in patients, providing better guidance to regulatory labelling and understanding of benefit/risk in specific populations. © 2014 The British Pharmacological Society.
Bauer, Natali; Eralp, Oya; Moritz, Andreas
2009-09-01
Tissue factor (TF)- and kaolin-activated thromboelastography (TEG) have been performed in a small number of healthy dogs, but reference intervals have not been assessed in a larger number of dogs. The goal of the current study was to establish reference intervals and assess intra-assay repeatability for kaolin-activated TEG in dogs. Additionally, the impact of sex and the influence of anticoagulant (native blood vs. recalcified citrate anticoagulated blood) were evaluated. Thromboelastography analyses were performed in 56 healthy dogs including German Shepherd Dogs (n = 19), Beagles (n = 15), and others (n = 22). Median age was 2 years (range: 1-6 years) and sex was evenly distributed (31 males and 25 females). To establish reference intervals, citrated whole-blood samples were collected, and TEG was performed 1 hr after sampling. Five TEG variables (R = reaction time; K = clot formation time; alpha = angle alpha; MA = maximal amplitude; G-value reflecting clot stability) were evaluated, and reference intervals were defined as the mean +/- 1.96-fold standard deviation. Intra-assay repeatability was assessed by calculating the pooled variance estimate in duplicate measurements of 6 healthy dogs. The effect of anticoagulant was assessed in 17 specimens. Reference intervals were as follows: R = 1.8-8.6 min; angle alpha = 36.9-74.6 degrees; K = 1.3-5.7 min; MA = 42.9-67.9 mm, and G = 3.2-9.6 Kdyn/cm(2). Coefficients of variation for R, K, angle alpha, MA, and G were 7.6%, 17.7%, 7.4%, 2.9%, and 6.6%, respectively. There was no significant impact of sex or anticoagulant on results. Interindividual variation was higher in native samples than in citrated whole blood. A limitation of the current study was that most of the samples were obtained from Beagles and German Shepherd Dogs. This study provides useful reference intervals for kaolin-activated TEG.
Ferley, D D; Hopper, D T; Vukovich, M D
2016-11-01
This study compared 6 weeks of incline treadmill interval training (INC) performed on a 10% treadmill grade using either sprint-like efforts or slower, longer bouts. 24 individuals were randomly assigned between 2 groups that each completed 2 INC and one 30-min level-grade sessions∙wk(-1). Training intensities, bout durations and the number of intervals per INC session were the velocity associated with VO2max (Vmax), 30 s and 10-14 (INCShort n=12), and 68%Vmax, ~3 min and 4-6 (INCLong n=12), respectively. All 30-min sessions were at 65%Vmax. Pre- and post-testing assessed VO2max; lactate threshold (VLT); running economy; and time-to-exhaustion at various conditions including 80%Vmax and 20% grade (CFMod). Both groups improved significantly in all tests; additionally, INCShort improved significantly more so in VLT and CFMod despite INCLong performing more than 2 times the running each INC session (P<0.05). Mean effect size (ES) of the relative improvement in a majority of tests revealed a trivial to very large ES of INCShort vs. INCLong training (ES range: 0.05-4.05). We conclude sprint-like INC better than slower, longer INC at improving a key determinant of distance running performance (VLT), and better at preparing individuals for running on courses with a variety of grades. © Georg Thieme Verlag KG Stuttgart · New York.
Nasis, I; Kortianou, E; Vasilopoulou, Μ; Spetsioti, S; Louvaris, Z; Kaltsakas, G; Davos, C H; Zakynthinos, S; Koulouris, N G; Vogiatzis, I
2015-10-01
Dynamic hyperinflation (DH) has a significant adverse effect on cardiovascular function during exercise in COPD patients. COPD patients with (n = 25) and without (n = 11) exercise-induced DH undertook an incremental (IET) and a constant-load exercise test (CLET) sustained at 75% peak work (WRpeak) prior to and following an interval cycling exercise training regime (set at 100% WRpeak with 30-s work/30-s rest intervals) lasting for 12 weeks. Cardiac output (Q) was assessed by cardio-bio-impedance (PhysioFlow, enduro, PF-O7) to determine Q mean response time (QMRT) at onset (QMRT(ON)) and offset (QMRT(OFF)) of CLET. Post-rehabilitation only those patients exhibiting exercise-induced DH demonstrated significant reductions in QMRT(ON) (from 82.2 ± 4.3 to 61.7 ± 4.2 s) and QMRT(OFF) (from 80.5 ± 3.8 to 57.2 ± 4.9 s ). These post-rehabilitation adaptations were associated with improvements in inspiratory capacity, thereby suggesting that mitigation of the degree of exercise-induced DH improves central hemodynamic responses in COPD patients. Copyright © 2015 Elsevier B.V. All rights reserved.
Effectiveness of Moderate Intensity Interval Training as an Index of Autonomic Nervous Activity
Ito, Takayoshi; Oi, Rie; Nishimura, Kazushi; Morita, Shuhei; Yaoi, Riyo
2016-01-01
The purpose of this study was to examine the effects of moderate intensity interval training from the change of the autonomic nervous activity. Ten male volunteers aged 21-22 years were studied. After 10-minute rest in a seated position, the subjects were asked to perform the strength of moderate cycling exercise in ergometer. Cycling rate was done in 50 times/min. Load resistance of the ergometer was set to 2.0 kgm. Subjects paused the exercise when the heart rate becomes 120 beats/min. Subjects have resumed the exercise when the heart rate returns to the value at rest. This trial was repeated twice. The experiment was ended when the heart rate of the subjects has returned to resting level. When the heart rate during exercise is maintained to less than 120 beats/min, sympathetic nerve activity during exercise did not work actively compared to the baseline. Vagus nerve activity after exercise cessation exceeds the baseline. It is clarified that the exercise as well as activating the vagus nerve activity stimulates the total autonomic nervous activity. It has revealed that at the time of interval training at moderate load the vagus nerve activity can be carried out. PMID:27957342
Effectiveness of Moderate Intensity Interval Training as an Index of Autonomic Nervous Activity.
Kai, Satoru; Nagino, Koji; Ito, Takayoshi; Oi, Rie; Nishimura, Kazushi; Morita, Shuhei; Yaoi, Riyo
2016-01-01
The purpose of this study was to examine the effects of moderate intensity interval training from the change of the autonomic nervous activity. Ten male volunteers aged 21-22 years were studied. After 10-minute rest in a seated position, the subjects were asked to perform the strength of moderate cycling exercise in ergometer. Cycling rate was done in 50 times/min. Load resistance of the ergometer was set to 2.0 kgm. Subjects paused the exercise when the heart rate becomes 120 beats/min. Subjects have resumed the exercise when the heart rate returns to the value at rest. This trial was repeated twice. The experiment was ended when the heart rate of the subjects has returned to resting level. When the heart rate during exercise is maintained to less than 120 beats/min, sympathetic nerve activity during exercise did not work actively compared to the baseline. Vagus nerve activity after exercise cessation exceeds the baseline. It is clarified that the exercise as well as activating the vagus nerve activity stimulates the total autonomic nervous activity. It has revealed that at the time of interval training at moderate load the vagus nerve activity can be carried out.
Ache-Dias, Jonathan; Dellagrana, Rodolfo A; Teixeira, Anderson S; Dal Pupo, Juliano; Moro, Antônio R P
2016-01-01
This study analyzed the effect of 4 weeks of jumping interval training (JIT), included in endurance training, on neuromuscular and physiological parameters. Eighteen recreational runners, randomized in control and experimental groups, performed 40 min of running at 70% of velocity at peak oxygen uptake, for 3 times per week. Additionally, the experimental group performed the JIT twice per week, which consisted of 4 to 6 bouts of continuous vertical jumps (30 s) with 5-min intervals. Three days before and after the training period, the countermovement (CMJ) and continuous jump (CJ30), isokinetic and isometric evaluation of knee extensors/flexors, progressive maximal exercise, and submaximal constant-load exercise were performed. The JIT provoked improvement in neuromuscular performance, indicated by (i) increased jump height (4.7%; effect size (ES) = 0.99) and power output (≈ 3.7%; ES ≈ 0.82) of CMJ and rate of torque development of knee extensors in isometric contraction (29.5%; ES = 1.02); (ii) anaerobic power and capacity, represented by the mean of jump height (7.4%; ES = 0.8), and peak power output (PPO) (5.6%; ES = 0.73) of the first jumps of CJ30 and the mean of jump height (10.2%, ES = 1.04) and PPO (9.5%, ES = 1.1), considering all jumps of CJ30; and (iii) aerobic power and capacity, represented by peak oxygen uptake (9.1%, ES = 1.28), velocity at peak oxygen uptake (2.7%, ES = 1.11), and velocity corresponding to the onset of blood lactate accumulation (9.7%, ES = 1.23). These results suggest that the JIT included in traditional endurance training induces moderate to large effects on neuromuscular and physiological parameters.
Varieties of Confidence Intervals.
Cousineau, Denis
2017-01-01
Error bars are useful to understand data and their interrelations. Here, it is shown that confidence intervals of the mean (CI M s) can be adjusted based on whether the objective is to highlight differences between measures or not and based on the experimental design (within- or between-group designs). Confidence intervals (CIs) can also be adjusted to take into account the sampling mechanisms and the population size (if not infinite). Names are proposed to distinguish the various types of CIs and the assumptions underlying them, and how to assess their validity is explained. The various CIs presented here are easily obtained from a succession of multiplicative adjustments to the basic (unadjusted) CI width. All summary results should present a measure of precision, such as CIs, as this information is complementary to effect sizes.
The effect of sampling rate on observed statistics in a correlated random walk.
Rosser, G; Fletcher, A G; Maini, P K; Baker, R E
2013-08-06
Tracking the movement of individual cells or animals can provide important information about their motile behaviour, with key examples including migrating birds, foraging mammals and bacterial chemotaxis. In many experimental protocols, observations are recorded with a fixed sampling interval and the continuous underlying motion is approximated as a series of discrete steps. The size of the sampling interval significantly affects the tracking measurements, the statistics computed from observed trajectories, and the inferences drawn. Despite the widespread use of tracking data to investigate motile behaviour, many open questions remain about these effects. We use a correlated random walk model to study the variation with sampling interval of two key quantities of interest: apparent speed and angle change. Two variants of the model are considered, in which reorientations occur instantaneously and with a stationary pause, respectively. We employ stochastic simulations to study the effect of sampling on the distributions of apparent speeds and angle changes, and present novel mathematical analysis in the case of rapid sampling. Our investigation elucidates the complex nature of sampling effects for sampling intervals ranging over many orders of magnitude. Results show that inclusion of a stationary phase significantly alters the observed distributions of both quantities.
Response-cue interval effects in extended-runs task switching: memory, or monitoring?
Altmann, Erik M
2017-09-26
This study investigated effects of manipulating the response-cue interval (RCI) in the extended-runs task-switching procedure. In this procedure, a task cue is presented at the start of a run of trials and then withdrawn, such that the task has to be stored in memory to guide performance until the next task cue is presented. The effects of the RCI manipulation were not as predicted by an existing model of memory processes in task switching (Altmann and Gray, Psychol Rev 115:602-639, 2008), suggesting that either the model is incorrect or the RCI manipulation did not have the intended effect. The manipulation did produce a theoretically meaningful pattern, in the form of a main effect on response time that was not accompanied by a similar effect on the error rate. This pattern, which replicated across two experiments, is interpreted here in terms of a process that monitors for the next task cue, with a longer RCI acting as a stronger signal that a cue is about to appear. The results have implications for the human factors of dynamic task environments in which critical events occur unpredictably.
Effects of varied doses of psilocybin on time interval reproduction in human subjects.
Wackermann, Jirí; Wittmann, Marc; Hasler, Felix; Vollenweider, Franz X
2008-04-11
Action of a hallucinogenic substance, psilocybin, on internal time representation was investigated in two double-blind, placebo-controlled studies: Experiment 1 with 12 subjects and graded doses, and Experiment 2 with 9 subjects and a very low dose. The task consisted in repeated reproductions of time intervals in the range from 1.5 to 5s. The effects were assessed by parameter kappa of the 'dual klepsydra' model of internal time representation, fitted to individual response data and intra-individually normalized with respect to initial values. The estimates kappa were in the same order of magnitude as in earlier studies. In both experiments, kappa was significantly increased by psilocybin at 90 min from the drug intake, indicating a higher loss rate of the internal duration representation. These findings are tentatively linked to qualitative alterations of subjective time in altered states of consciousness.
Fallahi, Aliasghar; Gaeini, Abbasali; Shekarfroush, Shahnaz; Khoshbaten, Ali
2015-09-01
The aim of this study was to investigate the effects of High-Intensity Interval Training (HIIT) on nitric oxide metabolites (NO2(-), NO3(-)) and myocardial infarct size after Ischemia/Reperfusion (I/R) injury in healthy male rats. A total of 44 Wistar rats were randomly divided into 4 groups including HIIT (n=8), HIIT + IR protocol (n=14), control (n=8), and control + IR (n=14). Each training session of HIIT consisted of 1 hour of exercise in three stages: 6-minute running at 50-60% VO2max for warm-up; 7 intervals of 7-minute running on treadmill with a slope of 5° to 20° (4 minutes with an intensity of 80-100% VO2max and 3 minutes at 50-60% VO2max); and 5-minute running at 50-60% VO2max for cool-down. The control group did not participate in any exercise program. Nitric Oxide (NO) and its metabolites were measured by using Griess reaction test. The results showed that eight weeks of exercise training exerted a significantly increasing effect on nitrite (8.55 μmol per liter, equivalent to 34.79%), nitrate (62.02 μmol per liter, equivalent to 149.48%), and NOx (66 μmol per liter, equivalent to 98.11%) in the HIIT group compared with the control group. The results showed myocardial infract size (IS) was significantly smaller (23.2%, P<0.001) in the exercise training group compared with the control group. Incremental changes in NO-NO3 (-), NO2 (-) axis are one of mechanisms through which HIIT program can protect the heart from I/R injury and decrease myocardial infarction.
Maia, Marianna F; Willardson, Jeffrey M; Paz, Gabriel A; Miranda, Humberto
2014-09-01
Recent evidence suggests that exercising the antagonist musculature acutely enhances subsequent performance for the agonist musculature. The purpose of this study was to examine the effects of different rest intervals between sets for exercises that involve antagonistic muscle groups, a technique referred to as antagonist paired sets (APS). Fifteen recreationally trained men were tested for knee extension (KE) exercise performance, with or without previous knee flexion (KF) exercise for the antagonist musculature. The following protocols were performed in random order with 10 repetition maximum loads for the KF and KE exercises: (a) traditional protocol (TP)-1 set of KE only to repetition failure; (b) paired sets with minimal allowable rest (PMR)-1 set of KF followed immediately by a set of KE; (c) P30-30-second rest between paired sets of KF and KE; (d) P1-1-minute rest between paired sets; (e) P3-3-minute rest between paired sets; and (f) P5-5-minute rest between paired sets. The number of repetitions performed and electromyographic (EMG) activity of vastus lateralis, vastus medialis (VM), and rectus femoris (RF) muscles were recorded during the KE set in each protocol. It was demonstrated that significantly greater KE repetitions were completed during the PMR, P30, and P1 protocols vs. the TP protocol. Significantly greater EMG activity was demonstrated for the RF muscle during the KE exercise in the PMR and P30 vs. the TP, P3, and P5, respectively. In addition, significantly greater EMG activity was demonstrated for the VM muscle during the PMR vs. all other protocols. The results of this study indicate that no rest or relatively shorter rest intervals (30 seconds and 1 minute) between APS might be more effective to elicit greater agonist repetition enhancement and muscle activation.
de Freitas Maia, Marianna; Willardson, Jeffrey M; Paz, Gabriel Andrade; Miranda, Humberto
2014-03-11
Recent evidence suggests that exercising the antagonist musculature acutely enhances subsequent performance for the agonist musculature. The purpose of the current study was to examine the effects of different rest intervals between sets for exercises that involve antagonistic muscle groups; a technique referred to as antagonist paired sets (APS). Fifteen recreationally-trained men were tested for knee extension (KE) exercise performance, with or without prior knee flexion (KF) exercise for the antagonist musculature. The following protocols were performed in random order and with 10 repetition maximum (10RM) loads for the KF and KE exercises: 1) traditional protocol (TP) - one set of KE only to repetition failure; 2) paired sets with minimal allowable rest (PMR) - one set of KF followed immediately by a set of KE; 3) P30 - 30 seconds rest between paired sets of KF and KE; 4) P1 - 1-minute rest between paired sets; 5) P3 - 3-minutes rest between paired sets; and 6) P5 - 5-minutes rest between paired sets. The number of repetitions performed and EMG activity of vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) muscles were recorded during the KE set in each protocol. It was demonstrated that significantly greater KE repetitions were completed during the PMR, P30 and P1 protocols versus the TP protocol. Significantly greater EMG activity was demonstrated for the RF muscle during the KE exercise in the PMR and P30 versus the TP, P3 and P5, respectively. In addition, significantly greater EMG activity was demonstrated for the VM muscle during the PMR versus all other protocols. The results of the current study indicate that no rest or relatively shorter rest intervals (30 sec and 1 min) between APS might be more effective to elicit greater agonist repetition enhancement and muscle activation.
Mood and selective attention in the cold: the effect of interval versus continuous exercise.
Muller, Matthew D; Muller, Sarah M; Kim, Chul-Ho; Ryan, Edward J; Gunstad, John; Glickman, Ellen L
2011-07-01
Both mood and cognitive function are altered in cold environments. Body warming through exercise may improve Stroop interference score and lessen total negative mood. The purpose of this study was to determine the effect of equal caloric bouts of interval (INT) and continuous (CONT) exercise on mood and selective attention in the cold. Eleven young men underwent two experimental trials in 5°C air. Both trials consisted of 90 min acute cold exposure (ACE), 30 min exercise (INT vs. CONT), and 60 min recovery (REC). The Profile of Mood States (POMS) and Stroop Color Word Test (SCWT) were administered at four time points. Mean body temperature decreased during ACE, increased during exercise, and decreased during REC. Repeated measures analysis of variance revealed a main effect for time for several of the POMS sub scores. In particular, negative mood was significantly decreased after exercise relative to ACE and then significantly increased during REC. Further, CONT appears to be more effective than INT at decreasing negative mood. Components of the SCWT supported both the arousal and distraction theories for simple perception, but no significant effects were shown for the interference score. In the cold, exercise decreases negative mood but does not appear to affect selective attention. Further mechanistic studies could determine the best mode and intensity of exercise for improving cognitive function in the cold.
Effect of oxatomide, an antiallergic agent, on QT interval in dogs.
Iwamoto, K; Ikeda, J; Nito, M; Kosaka, N; Ichikawa, S; Ohmori, K; Sakai, K
2001-01-01
Oxatomide (CAS 60607-34-3, KW-4354) is an effective antiallergic agent for allergic rhinitis, urticaria, pruritus cutaneous, and eczema/dermatitis, etc. Terfenadine (CAS 50679-08-8) and astemizole (CAS 68844-77-9), antiallergic agents, have been reported to induce QT prolongation leading to serious ventricular arrhythmia (torsades de pointes) as cardiovascular adverse effects. The present study was carried out to determine whether oxatomide and terfenadine have effects on QT interval as a single drug or in combination with itraconazole (CAS 84625-61-6), an antifungal agent with a CYP3A4 inhibitory effect, in conscious dogs. Terfenadine alone induced QT prolongation at the dose of 30 mg/kg p.o. When itraconazole was administered at the dose of 100 mg/kg p.o. 1 h before terfenadine administration, terfenadine induced QT prolongation at the dose of 10 mg/kg p.o. On the other hand, oxatomide did not induce QT prolongation either as a single agent at the dose of 30 mg/kg p.o. or in combination with itraconazole at the dose of 10 mg/kg p.o. The results present no evidence that oxatomide has the potential to provoke ventricular arrhythmia.
... before trying any type of interval training. Recent studies suggest, however, that interval training can be used safely for short periods even in individuals with heart disease. Also keep the risk of overuse injury in mind. If you rush into a strenuous workout before ...
Interval training in the boundaries of severe domain: effects on aerobic parameters.
Turnes, Tiago; de Aguiar, Rafael Alves; Cruz, Rogério Santos de Oliveira; Caputo, Fabrizio
2016-01-01
Although time spent at VO2max (t@VO2max) has been suggested as an optimal stimulus for the promotion of greater VO2max improvements, scientific findings supporting this notion are surprisingly still lacking. To investigate this, the present study described t@VO2max in two different severe-intensity interval training regimens and compared its effects on aerobic indexes after a 4-week intervention. Twenty-one recreational cyclists performed an incremental exercise test and six time-to-exhaustion tests on four different days to determine VO2max, lactate threshold (LT), critical power (CP) and the highest intensity (IHIGH) and lowest exercise duration (TLOW) at which VO2max was attained. Subjects were assigned to the lower (LO, n = 11, 4 × 5 min at 105% CP, 1 min recovery) or the upper severe-intensity training groups (UP, n = 10, 8 × 60% TLOW at 100% IHIGH, 1:2 work:recovery ratio). t@VO2max was measured during the first and last training sessions. A significantly higher t@VO2max was elicited in the UP during training sessions in comparison with the LO group (P < 0.05), and superior improvements were observed in VO2max (change in measure ± 95% confidence interval) (6.3 ± 1.9 vs. 3.3 ± 1.8%, P = 0.034 for interaction terms) and LT (54.8 ± 11.8 vs. 27.9 ± 11.3%, P = 0.023 for interaction terms). The other aerobic indexes were similarly improved between the groups. The present results demonstrated that UP training produced superior gains in VO2max and LT in comparison with LO training, which may be associated with the higher t@VO2max.
Effect of interstimulus interval on visual P300 in Parkinson's disease
Wang, L.; Kuroiwa, Y.; Kamitani, T.; Takahashi, T.; Suzuki, Y.; Hasegawa, O.
1999-01-01
OBJECTIVE—Visual event related potentials (ERPs) were studied during an oddball paradigm, to testify whether cognitive slowing in Parkinson's disease exists and to investigate whether cognitive information processing can be influenced by different interstimulus intervals (ISIs) of an oddball task in patients with Parkinson's disease and normal subjects. METHODS—ERPs and reaction time were measured in 38 non-demented patients with Parkinson's disease and 24 healthy elderly subjects. A visual oddball paradigm was employed to evoke ERPs, at three different interstimulus (ISI) intervals: ISI(S), 1600 ms; ISI(M), 3100 ms; and ISI(L), 5100 ms. The effect of ISIs on ERPs and reaction time was investigated. RESULTS—Compared with the normal subjects, P300 latency at Cz and Pz was significantly delayed after rare target stimuli in patients with Parkinson's disease only at ISI(L). Reaction time was prolonged in patients at all the three ISIs, compared with the normal controls. There was also significantly delayed N200 and reduced P300 amplitude at Cz and/or Pz to rare non-target stimuli in patients at the three ISIs, compared with the normal controls. During rare target visual stimulation, P300 latency and reaction time in the patients with Parkinson's disease and reaction time in the normal subjects were gradually prolonged as the ISI increased. CONCLUSION—Prolonged N200 latency to rare non-target stimuli might indicate that automatic cognitive processing was slowed in Parkinson's disease. Cognitive processing reflected by P300 latency to rare target stimuli was influenced by longer ISI in patients with Parkinson's disease. PMID:10486398
Solanki, Jayesh Dalpatbhai; Gadhavi, Bhakti P; Makwana, Amit H; Mehta, Hemant B; Shah, Chinmay J; Gokhale, Pradnya A
2016-01-01
To study the effect of disease duration, treatment and risk factors on QTc interval among young hypertensives. A case-control study was conducted on 142 hypertensives (60 males, 82 females) taking calcium channel blocker (CCB) or angiotensin-converting enzyme inhibitor (ACEI) as monotherapy. After blood pressure measurement, we recorded lead II electrocardiograph with minimum ten waveforms. QTc was derived from average of ten values using Bazett's formula. QTc interval >0.43 s in male and >0.45 s in female was considered abnormal. Cases had mean duration of hypertension 5 years, mean age of 40 years, and poor blood pressure control (systolic blood pressure >140 and diastolic blood pressure >90 mm of Hg). Newly diagnosed hypertensives had significantly higher QTc values than the matched known cases (0.44 vs. 0.42 s, P < 0.05). Known hypertensives did not differ significantly in QTc values by the duration of disease. CCB users showed small, insignificant disadvantage for abnormally prolonged QTc values than ACEI users. With coexisting diabetes, smoking, and positive family history of hypertension, there was odds risk of 7.69, 2.75, and 2.54, respectively for prolonged QTc. Our study showed prolonged QTc in hypertensives more so in newly diagnosed, unaffected by duration or use of ACEI, or CCB but associated with modifiable risk factors. This underscores high risk of repolarization abnormality-induced future events, suggesting early screening of hypertension, strict blood pressure control, optimum use of QTc measurement, and preventive pharmacotherapy to reduce this aftermath.
Kogawa, Rikitake; Okumura, Yasuo; Watanabe, Ichiro; Kofune, Masayoshi; Nagashima, Koichi; Mano, Hiroaki; Sonoda, Kazumasa; Sasaki, Naoko; Iso, Kazuki; Takahashi, Keiko; Ohkubo, Kimie; Nakai, Toshiko; Hirayama, Atsushi
2015-01-01
Background Complex fractionated atrial electrograms (CFAEs) and high dominant frequency (DF) are targets for atrial fibrillation (AF) ablation. Although adenosine triphosphate (ATP) is known to promote AF by shortening the atrial refractory period, its role in the pathogenesis of CFAEs and DF during AF is not fully understood. Methods We recorded electrical activity from a 64-electrode basket catheter placed in the left atrium (LA) of patients with paroxysmal AF (PAF, n=18) or persistent AF (PerAF, n=19) before ablation. Atrial electrogram fractionation intervals (FIs) and DFs were measured from bipolar electrograms of each adjacent electrode pair. Offline mean atrial FIs and DFs were obtained before bolus injection of 30 mg ATP. Peak effect was defined as an R–R interval >3 s. Results With ATP, the mean FI decreased (from 110.4±29.1 ms to 90.5±24.7 ms, P<0.0001) and DF increased (from 6.4±0.6 Hz to 7.1±0.8 Hz, P<0.0001) in all patients. There was no difference in the FI decrease between the two groups (−20.3±20.5 ms vs. −19.6±14.5 ms, P=0.6032), but the increase in DF was significantly greater in PAF patients (1.1±0.8 Hz vs. 0.3±0.6 Hz, P=0.0051). Conclusions ATP shortens atrial FIs and increases DFs in both PAF and PerAF patients. The significant increase in DF in PAF patients suggests that pathophysiologic characteristics related to the frequency of atrial fractionation change as atrial remodeling progresses. PMID:26702319
Vestibular-dependent inter-stimulus interval effects on sound evoked potentials of central origin.
Todd, N P M; Govender, S; Colebatch, J G
2016-11-01
Todd et al. (2014ab) have recently demonstrated the presence of vestibular-dependent contributions to auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs), including a particular deflection labeled as an N42/P52 prior to the long-latency AEPs N1 and P2. In this paper we report the results of an experiment to determine the effect of inter-stimulus interval (ISI) and regularity on potentials recorded above and below VEMP threshold. Five healthy, right-handed subjects were recruited and evoked potentials were recorded to binaurally presented sound stimulation, above and below vestibular threshold, at seven stimulus rates with ISIs of 212, 300, 424, 600, 848, 1200 and 1696 ms. The inner five intervals, i.e. 300, 424, 600, 848, 1200 ms, were presented twice in both regular and irregular conditions. ANOVA on the global field power (GFP) were conducted for each of four waves, N42, P52, N1 and P2 with factors of intensity, ISI and regularity. Both N42 and P52 waves showed significant ANOVA effects of intensity but no other main effects or interactions. In contrast both N1 and P2 showed additional effects of ISI, as well as intensity, and evidence of non-linear interactions between ISI and intensity. A source analysis was carried out consistent with prior work suggesting that when above vestibular threshold, in addition to bilateral superior temporal cortex, ocular, cerebellar and cingulate sources are recruited. Further statistical analysis of the source currents indicated that the origin of the interactions with intensity may be the ISI sensitivity of the vestibular-dependent sources. This in turn may reflect a specific vestibular preference for stimulus rates associated with locomotion, i.e. rates close to 2 Hz, or ISIs close to 500 ms, where saccular afferents show increased gain and the corresponding reflexes are most sensitive.
Trauma and memory: effects of post-event misinformation, retrieval order, and retention interval.
Paz-Alonso, Pedro M; Goodman, Gail S
2008-01-01
The present study concerned effects of misinformation, retrieval order, and retention interval on eyewitness memory for a traumatic event (a vivid murder). Relations between misinformation acceptance and compliance were also examined. The classic three-stage misinformation paradigm (Loftus, 1979) was employed, with a multi-component recognition test added. Either immediately or 2 weeks after viewing a distressing film, 232 adults read a narrative (misleading or control) about the murder and then took a recognition test that tapped memory for central and peripheral details. Test-item order either matched the chronology of the film or was randomly determined. Significant misinformation effects were obtained. Moreover, control participants were more accurate in response to questions about central than peripheral information; however, this was not so for misinformed participants. Sequential but not random retrieval order resulted in a higher proportion of correct responses for central as opposed to peripheral misinformation questions. Compliance was significantly related to misinformation effects. Delay increased participants' suggestibility, impaired memory accuracy, and produced higher confidence ratings for misinformed participants compared to controls. Findings indicate that even for a highly negative event, adults' memory is not immune to inaccuracies and suggestive influences.
Confidence intervals for single-case effect size measures based on randomization test inversion.
Michiels, Bart; Heyvaert, Mieke; Meulders, Ann; Onghena, Patrick
2017-02-01
In the current paper, we present a method to construct nonparametric confidence intervals (CIs) for single-case effect size measures in the context of various single-case designs. We use the relationship between a two-sided statistical hypothesis test at significance level α and a 100 (1 - α) % two-sided CI to construct CIs for any effect size measure θ that contain all point null hypothesis θ values that cannot be rejected by the hypothesis test at significance level α. This method of hypothesis test inversion (HTI) can be employed using a randomization test as the statistical hypothesis test in order to construct a nonparametric CI for θ. We will refer to this procedure as randomization test inversion (RTI). We illustrate RTI in a situation in which θ is the unstandardized and the standardized difference in means between two treatments in a completely randomized single-case design. Additionally, we demonstrate how RTI can be extended to other types of single-case designs. Finally, we discuss a few challenges for RTI as well as possibilities when using the method with other effect size measures, such as rank-based nonoverlap indices. Supplementary to this paper, we provide easy-to-use R code, which allows the user to construct nonparametric CIs according to the proposed method.
Bouts of Responding on Variable-Interval Schedules: Effects of Deprivation Level
ERIC Educational Resources Information Center
Shull, Richard L.
2004-01-01
Rats obtained food pellets on a variable-interval schedule of reinforcement by nose poking a lighted key. After training to establish baseline performance (with the mean variable interval set at either 60, 120, or 240 s), the rats were given free access to food during the hour just before their daily session. This satiation operation reduced the…
Bouts of Responding on Variable-Interval Schedules: Effects of Deprivation Level
ERIC Educational Resources Information Center
Shull, Richard L.
2004-01-01
Rats obtained food pellets on a variable-interval schedule of reinforcement by nose poking a lighted key. After training to establish baseline performance (with the mean variable interval set at either 60, 120, or 240 s), the rats were given free access to food during the hour just before their daily session. This satiation operation reduced the…
Vanegas, Gilmer; Lancien, Frédéric; Leprince, Jérôme; Vaudry, Hubert; Le Mével, Jean-Claude
2016-01-01
The QT interval of the electrocardiogram (ECG) is a measure of the duration of the ventricular depolarization and repolarization. In fish as in human, the QT interval is positively correlated with the RR interval of the ECG, a measure of the cardiac cycle length. Urotensin II (UII) is a neuropeptide that has been highly conserved from fish to human, and UII and its receptor (UT) are expressed in cardiovascular tissues including the heart. Although UII exerts potent cardiovascular actions, its possible effects on the QT interval have never been investigated. The goal of the present study was to provide insight into the potential effect of UII on the QT interval in an established in vivo trout model. To this end, the effects of UII on dorsal aortic blood pressure (PDA), RR, QT intervals and corrected QT (QTc) for RR interval, were investigated after intra-arterial (IA) injection of 5, 50 and 100 pmol UII. The effects of UII were compared to those of two structurally UII-related peptides (URPs), URP1 and URP2, and to those of arginine vasotocin (AVT), homolog of the mammalian arginine vasopressin. IA injection of vehicle or 5 pmol UII had no effect on the various parameters. At the 50-pmol dose, UII evoked its usual increase in PDA with a peak value observed 15 min after the injection (+22% from baseline, P<0.001). This hypertensive effect of UII was accompanied by a significant increase in the RR interval (+18%, P<0.001), i.e. a bradycardia, and these effects remained constant until the end of the recording. The highest dose of UII evoked similar hypertensive and bradycardic effects. Of interest, the QT interval did not change during the bradycardic action of UII (50 and 100 pmol) but the QTc interval significantly decreased. In trout pre-treated with urantide, a peptidic antagonist of UT, the hypertensive and bradycardic actions of 50 pmol UII were reduced 3-fold and no change occurred in the QT and QTc intervals. In trout pre-treated with blockers of the autonomic
ERIC Educational Resources Information Center
Woodruff-Pak, Diana S.; Seta, Susan E.; Roker, LaToya A.; Lehr, Melissa A.
2007-01-01
The aim of this study was to examine parameters affecting age differences in eyeblink classical conditioning in a large sample of young and middle-aged rabbits. A total of 122 rabbits of mean ages of 4 or 26 mo were tested at inter-stimulus intervals (ISIs) of 600 or 750 msec in the delay or trace paradigms. Paradigm affected both age groups…
ERIC Educational Resources Information Center
Woodruff-Pak, Diana S.; Seta, Susan E.; Roker, LaToya A.; Lehr, Melissa A.
2007-01-01
The aim of this study was to examine parameters affecting age differences in eyeblink classical conditioning in a large sample of young and middle-aged rabbits. A total of 122 rabbits of mean ages of 4 or 26 mo were tested at inter-stimulus intervals (ISIs) of 600 or 750 msec in the delay or trace paradigms. Paradigm affected both age groups…
[Chronobiological evaluation of effects biomarkers and sampling].
Andreoli, R; Manini, P; Alinovi, R; Goldoni, M; De Palma, G; Mutti, A
2005-01-01
Occupational exposure to oxidants is often associated with an increase in the levels of oxidative DNA damage in urine. Besides 8-hydroxy-2'-deoxyguanosine (8-oxo-dG), other products of position-8 guanine oxidation have been identified in urine, including 8-hydroxy-guanine (8-oxo-G) and 8-hydroxyguanosine (8-oxy-Guo). The aim of the present study was the characterization of these effect biomarkers in terms of inter- and intra-individuals varaibility, as well as in terms of their excretion profile during a 24 h-period. Urine samples were collected from 11 volunteers (6 samples/day). Urine concentrations of 8-oxo-G, 8-oxo-Guo, and 8-oxo-dG were determined by liquid chromatography-tandem mass spectrometry. The inter-individual variability, expressed as variation coefficient, was 85-150% for 8-oxo-G, 20-45% for 8-oxo-Guo, and 30-45% for 8-oxo-dG. The statistical anaysis for repeated measurements showed that none of the biomarkers was affected by significant variation during the day (one-way ANOVA, p < 0.05), thus excluding the existence of a circadian rhythm. We conclude that the sampling time is not critical for the assessment of oxidative DNA damage in urine.
Contrast loading: power output and rest interval effects on neuromuscular performance.
Sotiropoulos, Konstantinos; Smilios, Ilias; Douda, Helen; Chritou, Marios; Tokmakidis, Savvas P
2014-05-01
This study examined the effect of rest interval after the execution of a jump-squat set with varied external mechanical-power outputs on repeated-jump (RJ) height, mechanical power, and electromyographic (EMG) activity. Twelve male volleyball players executed 6 RJs before and 1, 3, 5, 7, and 10 min after the execution of 6 repetitions of jump squats with a load: maximized mechanical-power output (Pmax), 70% of Pmax, 130% of Pmax, and control, without extra load. RJ height did not change (P = .44) after the jump squats, mechanical power was higher (P = .02) 5 min after the 130%Pmax protocol, and EMG activity was higher (P = .001) after all exercise protocols compared with control. Irrespective of the time point, however, when the highest RJ set for each individual was analyzed, height, mechanical power, and EMG activity were higher (P = .001-.04) after all loading protocols compared with control, with no differences observed (P = .53-.72) among loads. Rest duration for a contrast-training session should be individually determined regardless of the load and mechanical-power output used to activate the neuromuscular system. The load that maximizes external mechanical-power output compared with a heavier or a lighter load, using the jump-squat exercise, is not more effective for increasing jumping performance afterward.
Atropine unmasks bed-rest effect - A spectral analysis of cardiac interbeat intervals
NASA Technical Reports Server (NTRS)
Goldberger, Ary L.; Goldwater, Danielle; Bhargava, Valmik
1986-01-01
Heart rate spectral data obtained for 10 male subjects between 35-49 years following orthostatic tolerance testing with lower body negative pressure prebed rest and after 7-10 days of bed rest, while on placebo and after intravenous atropine are analyzed. Comparison of the spectral atropine rms for subjects prebed rest and after bed rest reveal a decrease from 63 + or - 24 ms to 40 + or - 23 ms. It is observed that heart rate interval variability for subjects after bed rest and with atropine is reduced; the heart rate at bed rest with atropine is increased from 70.4 + or - 12.4 beats/min prebed rest to 83.7 + or - 18.9 beats/min; and the exercise tolerance time for subjects in the atropine prebed-rest phase (658 + or - 352 s) is higher than the bed-rest phase (505 + or - 252 s). It is noted that bed rest impairs the cardiovascular capacity to adaptively modulate physiological responses, atropine exposes bed-rest deconditioning effects, and spectral analysis is useful for studying the effects of bed-rest deconditioning on cardiac dynamics.
Atropine unmasks bed-rest effect - A spectral analysis of cardiac interbeat intervals
NASA Technical Reports Server (NTRS)
Goldberger, Ary L.; Goldwater, Danielle; Bhargava, Valmik
1986-01-01
Heart rate spectral data obtained for 10 male subjects between 35-49 years following orthostatic tolerance testing with lower body negative pressure prebed rest and after 7-10 days of bed rest, while on placebo and after intravenous atropine are analyzed. Comparison of the spectral atropine rms for subjects prebed rest and after bed rest reveal a decrease from 63 + or - 24 ms to 40 + or - 23 ms. It is observed that heart rate interval variability for subjects after bed rest and with atropine is reduced; the heart rate at bed rest with atropine is increased from 70.4 + or - 12.4 beats/min prebed rest to 83.7 + or - 18.9 beats/min; and the exercise tolerance time for subjects in the atropine prebed-rest phase (658 + or - 352 s) is higher than the bed-rest phase (505 + or - 252 s). It is noted that bed rest impairs the cardiovascular capacity to adaptively modulate physiological responses, atropine exposes bed-rest deconditioning effects, and spectral analysis is useful for studying the effects of bed-rest deconditioning on cardiac dynamics.
Hannon, Erin E; Soley, Gaye; Levine, Rachel S
2011-07-01
Effects of culture-specific experience on musical rhythm perception are evident by 12 months of age, but the role of culture-general rhythm processing constraints during early infancy has not been explored. Using a habituation procedure with 5- and 7-month-old infants, we investigated effects of temporal interval ratio complexity on discrimination of standard from novel musical patterns containing 200-ms disruptions. Infants were tested in three ratio conditions: simple (2:1), which is typical in Western music, complex (3:2), which is typical in other musical cultures, and highly complex (7:4), which is relatively rare in music throughout the world. Unlike adults and older infants, whose accuracy was predicted by familiarity, younger infants were influenced by ratio complexity, as shown by their successful discrimination in the simple and complex conditions but not in the highly complex condition. The findings suggest that ratio complexity constrains rhythm perception even prior to the acquisition of culture-specific biases.
Effects of high-intensity interval vs. continuous moderate exercise on intraocular pressure.
Conte, M; Baldin, A D; Russo, M R R R; Storti, L R; Caldara, A A; Cozza, H F P; Ciolac, E G
2014-09-01
Our purpose was to compare the acute effects of high-intensity interval training (HIT) vs. continuous moderate exercise (CME) on intraocular pressure (IOP) in healthy subjects. Fifteen young men (age=22.1±6 years) underwent 30 min of HIT (2 min of walking at 50% of reserve heart rate (HR) alternated with 1 min of running at 80% of reserve HR) and CME sessions (30 min of jogging/running at 60% of reserve HR) in random order (2-5 days between sessions). IOP was measured before (baseline), immediately after (post--exercise), 5 min after (Rec5) and 10 min after (Rec10) each exercise session. IOP was reduced post-exercise and remained reduced at Rec5 during both HIT and CME session, with no significant difference between interventions (~16% between 23%). However, IOP remained reduced at Rec10 only after HIT intervention (~19%), whereas IOP at Rec10 returned to levels similar to the observed at baseline during CME intervention. In summary, both HIT and CME equally reduced IOP immediately and 5 min after exercise session. However, only HIT was able to remain IOP reduced 10 min after exercise. These results suggest that HIT may be more effective than CME for reducing IOP in young healthy men.
Effects of interphase interval and stimulation form on dorsiflexors contraction force.
Springer, Shmuel
2015-01-01
Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation to restore movement to patients following orthopedic and neurological injuries. When applying NMES the goal is to induce the strongest contractions with minimal discomfort. This study aimed to determine whether introducing an interphase interval (IPI) to 400 μ sec biphasic pulses during stimulation of the dorsiflexor muscles would have the same effect on force production and stimulation discomfort when stimulation was controlled by constant current (CC) or constant voltage (CV). Eighteen healthy volunteers participated in the study. Each subject participated in one session. Electrically induced contraction (EIC) forces and degree of discomfort were measured during stimulation of the ankle dorsiflexors with 0, 100 and 200 μ sec IPI settings with CC or CV. Compared to IPI = 0 μ sec, introduction of a 200 μ sec IPI increased force production with CC stimulation without increasing discomfort. No other enhancements in the EIC force compared to IPI = 0 μ sec were found between the IPIs with CC or CV. IPI may increase the effectiveness of biphasic pulse with CC, but not with CV stimulation.
Effects of self-paced interval and continuous training on health markers in women.
Connolly, Luke J; Bailey, Stephen J; Krustrup, Peter; Fulford, Jonathan; Smietanka, Chris; Jones, Andrew M
2017-09-20
To compare the effects of self-paced high-intensity interval and continuous cycle training on health markers in premenopausal women. Forty-five inactive females were randomised to a high-intensity interval training (HIIT; n = 15), continuous training (CT; n = 15) or an inactive control (CON; n = 15) group. HIIT performed 5 × 5 min sets comprising repetitions of 30-s low-, 20-s moderate- and 10-s high-intensity cycling with 2 min rest between sets. CT completed 50 min of continuous cycling. Training was completed self-paced, 3 times weekly for 12 weeks. Peak oxygen uptake (16 ± 8 and 21 ± 12%), resting heart rate (HR) (-5 ± 9 and -4 ± 7 bpm) and visual and verbal learning improved following HIIT and CT compared to CON (P < 0.05). Total body mass (-0.7 ± 1.4 kg), submaximal walking HR (-3 ± 4 bpm) and verbal memory were enhanced following HIIT (P < 0.05), whereas mental well-being, systolic (-5 ± 6 mmHg) and mean arterial (-3 ± 5 mmHg) blood pressures were improved following CT (P < 0.05). Participants reported similar levels of enjoyment following HIIT and CT, and there were no changes in fasting serum lipids, fasting blood [glucose] or [glucose] during an oral glucose tolerance test following either HIIT or CT (P > 0.05). No outcome variable changed in the CON group (P > 0.05). Twelve weeks of self-paced HIIT and CT were similarly effective at improving cardiorespiratory fitness, resting HR and cognitive function in inactive premenopausal women, whereas blood pressure, submaximal HR, well-being and body mass adaptations were training-type-specific. Both training methods improved established health markers, but the adaptations to HIIT were evoked for a lower time commitment.
Yousaf-Khan, Uraujh; van der Aalst, Carlijn; de Jong, Pim A; Heuvelmans, Marjolein; Scholten, Ernst; Lammers, Jan-Willem; van Ooijen, Peter; Nackaerts, Kristiaan; Weenink, Carla; Groen, Harry; Vliegenthart, Rozemarijn; Ten Haaf, Kevin; Oudkerk, Matthijs; de Koning, Harry
2017-01-01
In the USA annual lung cancer screening is recommended. However, the optimal screening strategy (eg, screening interval, screening rounds) is unknown. This study provides results of the fourth screening round after a 2.5-year interval in the Dutch-Belgian Lung Cancer Screening trial (NELSON). Europe's largest, sufficiently powered randomised lung cancer screening trial was designed to determine whether low-dose CT screening reduces lung cancer mortality by ≥25% compared with no screening after 10 years of follow-up. The screening arm (n=7915) received screening at baseline, after 1 year, 2 years and 2.5 years. Performance of the NELSON screening strategy in the final fourth round was evaluated. Comparisons were made between lung cancers detected in the first three rounds, in the final round and during the 2.5-year interval. In round 4, 46 cancers were screen-detected and there were 28 interval cancers between the third and fourth screenings. Compared with the second round screening (1-year interval), in round 4 a higher proportion of stage IIIb/IV cancers (17.3% vs 6.8%, p=0.02) and higher proportions of squamous-cell, bronchoalveolar and small-cell carcinomas (p=0.001) were detected. Compared with a 2-year interval, the 2.5-year interval showed a higher non-significant stage distribution (stage IIIb/IV 17.3% vs 5.2%, p=0.10). Additionally, more interval cancers manifested in the 2.5-year interval than in the intervals of previous rounds (28 vs 5 and 28 vs 19). A 2.5-year interval reduced the effect of screening: the interval cancer rate was higher compared with the 1-year and 2-year intervals, and proportion of advanced disease stage in the final round was higher compared with the previous rounds. ISRCTN63545820. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Effect of vitamin E succinate on inflammatory cytokines induced by high-intensity interval training
Sarir, Hadi; Emdadifard, Ghodsieh; Farhangfar, Homayoun; TaheriChadorneshin, Hossein
2015-01-01
Aim and Scope: The anti-inflammatory effect of vitamin E under moderate exercises has been evaluated. However, the effect of vitamin E succinate, which has more potent anti-inflammatory effect than other isomers of vitamin E has not been evaluated. Therefore, the aim of the present study was to evaluate the effects of vitamin E succinate on tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) production induced by high-intensity interval training (HIIT). Materials and Methods: In the present study, 24 rats were randomly divided into control (C), supplementation (S), HIIT, and HIIT + supplementation (HIIT+S) groups. HIIT training protocol on a treadmill (at a speed of 40–54 m/min) and vitamin E succinate supplementation (60 mg/kg/day) was conducted for 6 weeks. Results: Serum IL-6 in the HIIT group significantly increased compared with the C group (350.42 ± 123.31 pg/mL vs 158.60 ± 41.96 pg/mL; P = 0.002). Also, serum TNF-α concentrations significantly enhanced (718.15 ± 133.42 pg/mL vs 350.87 ± 64.93 pg/mL; P = 0.001) in the HIIT group compared with the C group. Treatment of the training group with vitamin E numerically reduced IL-6 and TNF-α when compared with the HIIT group (217.31 ± 29.21 and 510.23 ± 217.88, respectively, P > 0.05). However, no significant changes were observed in serum TNF-α (P = 0.31) and IL-6 (P = 0.52) concentrations in the HIIT + S group compared with the C group. Conclusion: HIIT-induced IL-6 and TNF-α decreased by administration of Vitamin E succinate. PMID:26958053
ERIC Educational Resources Information Center
Ruscio, John; Mullen, Tara
2012-01-01
It is good scientific practice to the report an appropriate estimate of effect size and a confidence interval (CI) to indicate the precision with which a population effect was estimated. For comparisons of 2 independent groups, a probability-based effect size estimator (A) that is equal to the area under a receiver operating characteristic curve…
ERIC Educational Resources Information Center
Ruscio, John; Mullen, Tara
2012-01-01
It is good scientific practice to the report an appropriate estimate of effect size and a confidence interval (CI) to indicate the precision with which a population effect was estimated. For comparisons of 2 independent groups, a probability-based effect size estimator (A) that is equal to the area under a receiver operating characteristic curve…
Stein, Werner; Misselwitz, Björn; Schmidt, Stefan
2008-01-01
Following vaginal delivery of the first twin, the further management to deliver the second twin is in dispute. Controversial discussions have taken place on the importance of the time interval between the birth of the first and the second twin. To evaluate factors influencing twin-to-twin delivery time interval, and short-term outcome of the second twin in a complete population-based cohort in Hesse, Germany. Study design. In a population-based cohort study, between January 1990 and December 2004, all twin pregnancies of > or =34+0 weeks' gestation with a vaginally delivered first twin were evaluated. Pregnancies with intrauterine death of either one of the twins before the onset of labour, complicated by twin-twin transfusion or fetal malformations were excluded. Some 4,110 twin pregnancies were analysed. Maternal and fetal characteristics for an increased twin-to-twin delivery time interval and its impact on an adverse short-term neonatal outcome, and the effect of the twin-to-twin delivery interval on umbilical arterial pH and base excess of the second twin have been investigated. In univariate analysis, breech, transverse lie, birth weight discordance with the second twin > or =20% larger, fetal distress, vaginal operative delivery, and caesarean section were associated with an increased time interval. Maternal characteristics were not related to an increased time interval. Increasing time interval was related to a decline in the mean umbilical arterial pH and base excess, and fetal acidosis, Apgar score <7 after 1, 5 and 10 min. In multivariate analysis, birth weight discordance, mode of delivery, and twin-to-twin delivery time interval were associated with an adverse short-term outcome of the second twin. As twin-to-twin delivery time interval seems to be an independent risk factor for adverse short-term outcome of the second twin, it should be kept short.
The effect of the rotator interval on glenohumeral kinematics during abduction.
Haghpanah, Babak; Walley, Kempland C; Hingsammer, Andreas; Harlow, Ethan R; Oftadeh, Ramin; Vaziri, Ashkan; Ramappa, Arun J; DeAngelis, Joseph P; Nazarian, Ara
2016-01-28
The rotator interval (RI) has been exploited as a potentially benign point of entry into the glenohumeral (GH) joint. Bounded by the supraspinatus, subscapularis and coracoid process of the scapula, the RI is believed to be important in the shoulder's soft tissue balancing and function. However, the role of the RI in shoulder kinematics is not fully understood. The purpose of this study is to describe the effect of the RI on GH motion during abduction of the arm. Six shoulders from three cadaveric torsos were studied to assess the impact of changes in the RI during abduction under four conditions: Intact (Baseline), Opened, Repaired (repaired with side-to-side tissue approximation, no overlap) and Tightened (repaired with 1 cm overlap). For each group, the GH translation and area under the Curve (AUC) were measured during abduction using an intact cadaveric shoulder (intact torso). GH kinematics varied in response to each intervention and throughout the entire abduction arc. Opening the RI caused a significant change in GH translation. The Repair and Tightened groups behaved similarly along all axes of GH motion. The RI is central to normal GH kinematics. Any insult to the tissue's integrity alters the shoulder's motion throughout abduction. In this model, closing the RI side-to-side has the same effect as tightening the RI. Since suture closure may offer the same benefit as tightening the RI, clinicians should consider this effect when treating patients with shoulder laxity. This investigation provides an improved perspective on the role of the RI on GH kinematics during abduction. When managing shoulder pathology, surgeons should consider how these different methods of RI closure affect the joint's motion. In different circumstances, the surgical approach to the RI can be tailored to address each patient's specific needs.
Effect of repeated tissue sampling on growth rates of juvenile loggerhead turtles Caretta caretta.
Bjorndal, Karen A; Reich, Kimberly J; Bolten, Alan B
2010-02-17
We evaluated the effect of repeated tissue sampling on growth rates of juvenile loggerhead sea turtles Caretta caretta. Samples of blood, skin, and scute (keratinized epidermal layer covering the bony shell) were collected at 3 intervals over a 120 d period from 37 loggerheads; 8 control turtles were not sampled. No infections or scarring occurred at the sampling sites, and growth in mass of experimental and control turtles was not significantly different. The sampling regime did not affect the health or physiological status of the turtles.
NASA Astrophysics Data System (ADS)
Li, Hui-Jia; Cheng, Qing; Mao, He-Jin; Wang, Huanian; Chen, Junhua
2017-03-01
The study of community structure is a primary focus of network analysis, which has attracted a large amount of attention. In this paper, we focus on two famous functions, i.e., the Hamiltonian function H and the modularity density measure D, and intend to uncover the effective thresholds of their corresponding resolution parameter γ without resolution limit problem. Two widely used example networks are employed, including the ring network of lumps as well as the ad hoc network. In these two networks, we use discrete convex analysis to study the interval of resolution parameter of H and D that will not cause the misidentification. By comparison, we find that in both examples, for Hamiltonian function H, the larger the value of resolution parameter γ, the less resolution limit the network suffers; while for modularity density D, the less resolution limit the network suffers when we decrease the value of γ. Our framework is mathematically strict and efficient and can be applied in a lot of scientific fields.
Brown, Denver M Y; Teseo, Amanda J; Bray, Steven R
2016-08-01
This study examined the effect of autonomous motivational priming on motivation, attitudes and intentions towards high-intensity interval training (HIT). Participants (N = 42) performed a graded exercise test to determine their peak aerobic power (WPEAK). At a subsequent testing session, participants were randomised to complete either an autonomous or neutral motivational priming task followed by a 10 × 1 HIT exercise protocol, alternating 1-min bouts of hard (70% WPEAK) and light (12.5% WPEAK) exercises for 20 min. Participants primed with autonomous motivation reported greater enjoyment, P = .009, ηp(2) = .16, and perceived competence, P = .005, ηp(2) = .18, post-exercise compared to those in the neutral priming condition. Participants in the autonomous motivational priming condition also reported more positive attitudes, P = .014, ηp(2) = .14, towards HIT; however, there was no difference between the conditions for task motivation during HIT or intentions, P = .53, ηp(2) = .01, to engage in HIT. These findings highlight autonomous motivational priming as a method of enhancing affective and motivational experiences regarding HIT.
Grgic, Jozo; Schoenfeld, Brad J; Skrepnik, Mislav; Davies, Timothy B; Mikulic, Pavle
2017-09-20
Rest interval (RI) duration is an important resistance-training variable underlying gain in muscular strength. Recommendations for optimal RI duration for gains in muscular strength are largely inferred from studies examining the acute resistance training effects, and the generalizability of such findings to chronic adaptations is uncertain. The goals of this systematic literature review are: (i) to aggregate findings and interpret the studies that assessed chronic muscular strength adaptations to resistance training interventions involving different RI durations, and (ii) to provide evidence-based recommendations for exercise practitioners and athletes. The review was performed according to the PRISMA guidelines with a literature search encompassing five databases. Methodological quality of the studies was evaluated using a modified version of the Downs and Black checklist. Twenty-three studies comprising a total of 491 participants (413 males and 78 females) were found to meet the inclusion criteria. All studies were classified as being of good to moderate methodological quality; none of the studies were of poor methodological quality. The current literature shows that robust gains in muscular strength can be achieved even with short RIs (< 60 s). However, it seems that longer duration RIs (> 2 min) are required to maximize strength gains in resistance-trained individuals. With regard to untrained individuals, it seems that short to moderate RIs (60-120 s) are sufficient for maximizing muscular strength gains.
Effect of interstimulus interval on cortical proprioceptive responses to passive finger movements.
Smeds, Eero; Piitulainen, Harri; Bourguignon, Mathieu; Jousmäki, Veikko; Hari, Riitta
2017-01-01
Shortening of the interstimulus interval (ISI) generally leads to attenuation of cortical sensory responses. For proprioception, however, this ISI effect is still poorly known. Our aim was to characterize the ISI dependence of movement-evoked proprioceptive cortical responses and to find the optimum ISI for proprioceptive stimulation. We measured, from 15 healthy adults, magnetoencephalographic responses to passive flexion and extension movements of the right index finger. The movements were generated by a movement actuator at fixed ISIs of 0.5, 1, 2, 4, 8, and 16 s, in separate blocks. The responses peaked at ~ 70 ms (extension) and ~ 90 ms (flexion) in the contralateral primary somatosensory cortex. The strength of the cortical source increased with the ISI, plateauing at the 8-s ISI. Modeling the ISI dependence with an exponential saturation function revealed response lifetimes of 1.3 s (extension) and 2.2 s (flexion), implying that the maximum signal-to-noise ratio (SNR) in a given measurement time is achieved with ISIs of 1.7 s and 2.8 s respectively. We conclude that ISIs of 1.5-3 s should be used to maximize SNR in recordings of proprioceptive cortical responses to passive finger movements. Our findings can benefit the assessment of proprioceptive afference in both clinical and research settings.
Wu, Fen; Parvez, Faruque; Ahmed, Alauddin; Eunus, Mahbub; McClintock, Tyler R.; Patwary, Tazul Islam; Islam, Tariqul; Ghosal, Anajan Kumar; Islam, Shahidul; Hasan, Rabiul; Levy, Diane; Sarwar, Golam; Slavkovich, Vesna; van Geen, Alexander; Graziano, Joseph H.
2013-01-01
Background: Arsenic exposure from drinking water has been associated with heart disease; however, underlying mechanisms are uncertain. Objective: We evaluated the association between a history of arsenic exposure from drinking water and the prolongation of heart rate–corrected QT (QTc), PR, and QRS intervals. Method: We conducted a study of 1,715 participants enrolled at baseline from the Health Effects of Arsenic Longitudinal Study. We assessed the relationship of arsenic exposure in well water and urine samples at baseline with parameters of electrocardiogram (ECG) performed during 2005–2010, 5.9 years on average since baseline. Results: The adjusted odds ratio (OR) for QTc prolongation, defined as a QTc ≥ 450 msec in men and ≥ 460 msec in women, was 1.17 (95% CI: 1.01, 1.35) for a 1-SD increase in well-water arsenic (108.7 µg/L). The positive association appeared to be limited to women, with adjusted ORs of 1.24 (95% CI: 1.05, 1.47) and 1.24 (95% CI: 1.01, 1.53) for a 1-SD increase in baseline well-water and urinary arsenic, respectively, compared with 0.99 (95% CI: 0.73, 1.33) and 0.86 (95% CI: 0.49, 1.51) in men. There were no apparent associations of baseline well-water arsenic or urinary arsenic with PR or QRS prolongation in women or men. Conclusions: Long-term arsenic exposure from drinking water (average 95 µg/L; range, 0.1–790 µg/L) was associated with subsequent QT-interval prolongation in women. Future longitudinal studies with repeated ECG measurements would be valuable in assessing the influence of changes in exposure. PMID:23384555
Habimana-Kabano, Ignace; Broekhuis, Annelet; Hooimeijer, Pieter
2015-01-01
In 2005, a WHO consultation meeting on pregnancy intervals recommended a minimum interval of 6 months after a pregnancy disruption and an interval of two years after a live birth before attempting another pregnancy. Since then, studies have found contradictory evidence on the effect of shorter intervals after a pregnancy disruption. A binary regression analysis on 21532 last pregnancy outcomes from the 2000, 2005, and 2010 Rwanda Demographic and Health Surveys was done to assess the combined effects of the preceding pregnancy outcome and the interpregnancy intervals (IPIs) on fetal mortality in Rwanda. Risks of pregnancy loss are higher for primigravida and for mothers who lost the previous pregnancy and conceived again within 24 months. After a live birth, interpregnancy intervals less than two years do not increase the risk of a pregnancy loss. This study also confirms higher risks of fetal death when IPIs are beyond 5 years. An IPI of longer than 12 months after a fetal death is recommended in Rwanda. Particular attention needs to be directed to postpregnancy abortion care and family planning programs geared to spacing pregnancies should also include spacing after a fetal death. PMID:26613103
Schmidt, James R.
2016-01-01
The present report further investigates the proportion easy effect, a conflict-free version of the proportion congruent effect. In the proportion easy paradigm, it is observed that the difference in performance between easy (high contrast) and hard (low contrast) items is smaller in a task with mostly hard items relative to a task with mostly easy items. This effect has been interpreted as evidence for temporal learning: participants learn a faster pace (i.e., rhythm of responding) in the mostly easy context, which boosts the contrast effect, and a slower pace in the mostly hard context. In the present experiment, intervals between trials were either fixed or randomly varied from trial to trial. Interestingly, the proportion easy effect was still present with variable intervals. These data suggest that participants do not learn the regularity in timing from one response to the next (which was highly inconsistent with variable intervals). As one alternative, participants might be learning the intervals between stimulus onset and responses, which were not manipulated. They could then use this learned timing information to prepare for responding at the anticipated time, resulting in rhythmic responding. The results further imply that variable response-stimulus intervals are insufficient for controlling for rhythmic biases. PMID:27199861
Fuller, Joel T; Amado, Avelino; Emmerik, Richard E A van; Hamill, Joseph; Buckley, Jonathan D; Tsiros, Margarita D; Thewlis, Dominic
2016-02-01
The presence of long-range correlations (self-similarity) in the stride-to-stride fluctuations in running stride interval has been used as an indicator of a healthy adaptable system. Changes to footfall patterns when running with minimalist shoes could cause a less adaptable running gait. The purpose of this study was to investigate stride interval variability and the degree of self-similarity of stride interval in runners wearing minimalist and conventional footwear. Twenty-six trained habitual rearfoot footfall runners, unaccustomed to running in minimalist footwear, performed 6-min sub-maximal treadmill running bouts at 11, 13 and 15 km·h(-1) in minimalist and conventional shoes. Force sensitive resistors were placed in the shoes to quantify stride interval (time between successive foot contacts). Footfall position, stride interval mean and coefficient of variation (CV), were used to assess performance as a function of shoe type. Long-range correlations of stride interval were assessed using detrended fluctuation analysis (α). Mean stride interval was 1-1.3% shorter (P=0.02) and 27% of runners adopted a midfoot footfall (MFF) in the minimalist shoe. There was a significant shoe effect on α and shoe*speed*footfall interaction effect on CV (P<0.05). Runners that adopted a MFF in minimalist shoes, displayed reduced long-range correlations (P<0.05) and CV (P<0.06) in their running stride interval at the 15 km·h(-1) speed. The reduced variability and self-similarity observed for runners that changed to a MFF in the minimalist shoe may be suggestive of a system that is less flexible and more prone to injury.
Reversing the Signaled Magnitude Effect in Delayed Matching to Sample: Delay-Specific Remembering?
ERIC Educational Resources Information Center
White, K. Geoffrey; Brown, Glenn S.
2011-01-01
Pigeons performed a delayed matching-to-sample task in which large or small reinforcers for correct remembering were signaled during the retention interval. Accuracy was low when small reinforcers were signaled, and high when large reinforcers were signaled (the signaled magnitude effect). When the reinforcer-size cue was switched from small to…
Psychophysiological effects of music on acute recovery from high-intensity interval training.
Jones, Leighton; Tiller, Nicholas B; Karageorghis, Costas I
2017-03-01
Numerous studies have examined the multifarious effects of music applied during exercise but few have assessed the efficacy of music as an aid to recovery. Music might facilitate physiological recovery via the entrainment of respiratory rhythms with music tempo. High-intensity exercise training is not typically associated with positive affective responses, and thus ways of assuaging negative affect warrant further exploration. This study assessed the psychophysiological effects of music on acute recovery and prevalence of entrainment in between bouts of high-intensity exercise. Thirteen male runners (Mage=20.2±1.9years; BMI=21.7±1.7; V̇O2 max=61.6±6.1mL·kg·min(-1)) completed three exercise sessions comprising 5×5-min bouts of high-intensity intervals interspersed with 3-min periods of passive recovery. During recovery, participants were administered positively-valenced music of a slow-tempo (55-65bpm), fast-tempo (125-135bpm), or a no-music control. A range of measures including affective responses, RPE, cardiorespiratory indices (gas exchange and pulmonary ventilation), and music tempo-respiratory entrainment were recorded during exercise and recovery. Fast-tempo, positively-valenced music resulted in higher Feeling Scale scores throughout recovery periods (p<0.01, ηp(2)=0.38). There were significant differences in HR during initial recovery periods (p<0.05, ηp(2)=0.16), but no other music-moderated differences in cardiorespiratory responses. In conclusion, fast-tempo, positively-valenced music applied during recovery periods engenders a more pleasant experience. However, there is limited evidence that music expedites cardiorespiratory recovery in between bouts of high-intensity exercise. These findings have implications for athletic training strategies and individuals seeking to make high-intensity exercise sessions more pleasant.
Effects of interval and continuous exercise training on autonomic cardiac function in COPD patients.
Rodríguez, Diego A; Arbillaga, Ane; Barberan-Garcia, Anael; Ramirez-Sarmiento, Alba; Torralba, Yolanda; Vilaró, Jordi; Gimeno-Santos, Elena; Gea, Joaquim; Orozco-Levi, Mauricio; Roca, Josep; Marco, Ester
2016-01-01
Both interval (IT) and continuous (CT) exercise training results in an improvement of aerobic capacity in patients with chronic obstructive pulmonary disease (COPD); however, their effects on cardiac autonomic function remains unclear. The aim of our study was to evaluate the effect of a supervised CT vs IT on autonomic cardiac function in COPD patients. COPD patients were divided into two different groups according to training modality (IT or CT). Autonomic cardiac dysfunction (ACD) was defined as a heart rate recovery lower than 12 bpm heart rate after the first minute of maximal exercise (HRR1 ) and an abnormal chronotropic response (CR) to exercise (<80%). A total of 29 patients {mean [standard deviation (SD)] age: 68 (8) years, %FEV1 : 42 (13) predicted} were trained (15 subjects in the CT group, 14 subjects in the IT group). After training, both groups increased peak oxygen consumption [mean difference ΔVO2 peak: 156 mL/min (P = 0.04) on IT; and 210 mL/min (P = 0.01) on CT], HRR1 [IT, from 10.4 (5) to 13.8 (5) bpm (P = 0.04); and CT, from 14.3 (5) to 17.7 (5) bpm (P = 0.04)] and CR [IT, from 57% (22) to 81% (9) (P = 0.001); and CT, from 48% (28) to 73% (17) (P = 0.001)]. Sixteen patients showed ACD. Among these patients, HRR1 (P = 0.01 for IT and P = 0.04 for CT) and CR (P = 0.001 for IT and P = 0.002 for CT) were enhanced after training. Both IT and CT exercise training improve heart rate recovery and CR in COPD patients. These benefits could help to individualize exercise training. © 2014 John Wiley & Sons Ltd.
Kinetic analysis of complex training rest interval effect on vertical jump performance.
Jensen, Randall L; Ebben, William P
2003-05-01
Complex training has been recommended as a method of incorporating plyometrics with strength training. Some research suggests that plyometric performance is enhanced when performed 3-4 minutes after the strength training set, whereas other studies have failed to find any complex training advantage when plyometrics are performed immediately after the strength training portion of the complex. The purpose of this study was to determine if there is an ergogenic advantage associated with complex training and if there is an optimal time for performing plyometrics after the strength training set. Subjects were 21 NCAA Division I athletes who performed a countermovement vertical jump, a set of 5 repetitions maximum (5 RM) squats, and 5 trials of countermovement vertical jump at intervals of 10 seconds and 1, 2, 3, and 4 minutes after the squat. Jump height and peak ground reaction forces were acquired via a force platform. The pre-squat jump performance was compared with the post-squat jumps. Repeated measures ANOVA determined a difference (p effect (p > 0.05) was found comparing subsequent jumps (0.72-0.76 m) to the pre-squat condition (0.74 m). When comparing high to low strength individuals, there was no effect on jump performance following the squat (p > 0.05). In conclusion, complex training does not appear to enhance jumping performance significantly and actually decreases it when the jump is performed immediately following the strength training set; however, a nonsignificant trend toward improvement seemed to be present. Therefore to optimize jump performance it appears that athletes should not perform jumps immediately following resistance training. It may be possible that beyond 4 minutes of recovery performance could be enhanced; however, that was not within the scope of the current study.
ERIC Educational Resources Information Center
Cariveau, Tom; Kodak, Tiffany; Campbell, Vincent
2016-01-01
We replicated and extended the study by Koegel, Dunlap, and Dyer (1980) by examining the effects of 3 intertrial-interval (ITI) durations on skill acquisition in 2 children with autism spectrum disorders. Specifically, we compared the effect of short (2 s), progressive (2 s to 20 s), and long (20 s) ITIs on participants' mastery of tacts or…
ERIC Educational Resources Information Center
Cariveau, Tom; Kodak, Tiffany; Campbell, Vincent
2016-01-01
We replicated and extended the study by Koegel, Dunlap, and Dyer (1980) by examining the effects of 3 intertrial-interval (ITI) durations on skill acquisition in 2 children with autism spectrum disorders. Specifically, we compared the effect of short (2 s), progressive (2 s to 20 s), and long (20 s) ITIs on participants' mastery of tacts or…
Gerami, Farzad; Moghaddam, Parviz R; Ghorbani, Reza; Hassani, Abbas
2016-01-01
In order to evaluate the effect of irrigation intervals and cattle manure levels on morphological traits, essential oil content and yield of oregano, an experiment was conducted at the experimental Farm of the Faculty of Agriculture, Urmia University, Iran. The experimental design was split-plots, arranged in randomized complete blocks with three replications. Main plots including irrigation intervals (1, 2 and 3 weeks) and four levels of cattle manure at 0, 10, 20 and 30 t ha-1 were allocated to sub plots. Our results showed that increasing irrigation intervals reduced values of all morphological traits except for proportion of stems. Also, values for stems number, plant spread, stem diameter, leaf area, fresh and dry herb yield increased by increasing cattle manure levels. On the other hand, morphological traits not influenced by interaction of treatments except for plant spread and leaf area. The highest essential oil content (2.07%) and yield (66.62 kg ha-1) obtained in highest irrigation intervals and cattle manure levels. Whereas, 1 week irrigation interval without use of cattle manure produce lowest essential oil content (1.55%). For essential oil yield, the lowest value (46.37 kg ha-1) was found in 2 weeks irrigation interval with application of 20 t ha-1 cattle manure.
Finite-size effects on return interval distributions for weakest-link-scaling systems
NASA Astrophysics Data System (ADS)
Hristopulos, Dionissios T.; Petrakis, Manolis P.; Kaniadakis, Giorgio
2014-05-01
The Weibull distribution is a commonly used model for the strength of brittle materials and earthquake return intervals. Deviations from Weibull scaling, however, have been observed in earthquake return intervals and the fracture strength of quasibrittle materials. We investigate weakest-link scaling in finite-size systems and deviations of empirical return interval distributions from the Weibull distribution function. Our analysis employs the ansatz that the survival probability function of a system with complex interactions among its units can be expressed as the product of the survival probability functions for an ensemble of representative volume elements (RVEs). We show that if the system comprises a finite number of RVEs, it obeys the κ-Weibull distribution. The upper tail of the κ-Weibull distribution declines as a power law in contrast with Weibull scaling. The hazard rate function of the κ-Weibull distribution decreases linearly after a waiting time τc∝n1/m, where m is the Weibull modulus and n is the system size in terms of representative volume elements. We conduct statistical analysis of experimental data and simulations which show that the κ Weibull provides competitive fits to the return interval distributions of seismic data and of avalanches in a fiber bundle model. In conclusion, using theoretical and statistical analysis of real and simulated data, we demonstrate that the κ-Weibull distribution is a useful model for extreme-event return intervals in finite-size systems.
Effect of sex on the acute skeletal muscle response to sprint interval exercise.
Skelly, Lauren E; Gillen, Jenna B; MacInnis, Martin J; Martin, Brian J; Safdar, Adeel; Akhtar, Mahmood; MacDonald, Maureen J; Tarnopolsky, Mark A; Gibala, Martin J
2017-03-01
What is the central question of this study? Are there sex-based differences in the acute skeletal muscle response to sprint interval training (SIT)? What is the main finding and its importance? In response to a SIT protocol that involved three 20 s bouts of 'all-out' cycling, the expression of multiple genes associated with mitochondrial biogenesis, metabolic control and structural remodelling was largely similar between men and women matched for fitness. Our findings cannot explain previous reports of sex-based differences in the adaptive response to SIT and suggest that the mechanistic basis for these differences remains to be elucidated. A few studies have reported sex-based differences in response to several weeks of sprint interval training (SIT). These findings may relate to sex-specific responses to an acute session of SIT. We tested the hypothesis that the acute skeletal muscle response to SIT differs between sexes. Sedentary but healthy men (n = 10) and women (n = 9) were matched for age (22 ± 3 versus 22 ± 3 years old) and cardiorespiratory fitness [45 ± 7 versus 43 ± 10 ml O2 (kg fat-free mass)(-1) min(-1) ], with women tested in the mid-follicular phase of their menstrual cycles. Subjects performed three 20 s 'all-out' cycling efforts against a resistance of 5% of body mass, interspersed with 2 min of recovery. Relative mean power outputs [7.6 ± 0.5 versus 7.5 ± 0.9 W (kg fat-free mass)(-1) ] were similar between men and women (P > 0.05). Furthermore, there were no differences in the exercise-induced changes in mRNA expression of PGC-1α, PRC, PPARD, SIRT1, RIP140, HSL, HKII, PDK4, PDP1, FOXO3, MURF-1, Myf5, MyoD and VEGFA at 3 h of recovery versus rest (P < 0.05, main effect of time). The only sex-specific responses to exercise were an increase in the mRNA expression of GLUT4 and LPL in women only and Atrogin-1 in men only (P < 0.05). Women also had higher expression of HKII and lower expression of FOXO3 compared
Tong, Tomas K.; Kong, Zhaowei; Shi, Xueying
2017-01-01
This study compared the effects of a single bout of resistance exercise (RES) on glycemic homeostasis to isotime sprint interval exercise (SIE) using a within-subjects design. Nineteen nondiabetic males (age: 23.3 ± 0.7 yrs; height: 173.1 ± 1.2 cm; weight: 79.1 ± 4.8 kg; % fat: 22.5 ± 2.5%) were studied. RES involved nine exercises of 10 repetitions at 75% 1-RM using a 2 : 2 s tempo and was interspersed with a one-minute recovery; SIE involved four 30 s' all-out cycling effort interspersed with four minutes of active recovery. Plasma glucose and insulin in response to a 75 g oral glucose tolerance test were assessed 12 h after exercise. In comparison to a no exercise control trial (CON), the area under curve (AUC) of plasma glucose was reduced with both RES and SIE (P < 0.05), while insulin AUC was only reduced with RES. Cederholm, Gutt, Matsuda, and HOMA indices were improved (P < 0.05) following RES compared to CON. Corresponding changes following SIE were only found in Cederholm and Gutt indices (P < 0.05). No difference was found in plasma variables and indices between RES and SIE (P > 0.05). Such findings suggest that the RES may represent a potential alternative to the SIE in the development of time-efficient lifestyle intervention strategies for improving diabetes risk factors in healthy populations. PMID:28349072
Effect of high-intensity interval training on cardiovascular function, VO2max, and muscular force.
Astorino, Todd A; Allen, Ryan P; Roberson, Daniel W; Jurancich, Matt
2012-01-01
The purpose of this study was to examine the effects of short-term high-intensity interval training (HIIT) on cardiovascular function, cardiorespiratory fitness, and muscular force. Active, young (age and body fat = 25.3 ± 4.5 years and 14.3 ± 6.4%) men and women (N = 20) of a similar age, physical activity, and maximal oxygen uptake (VO2max) completed 6 sessions of HIIT consisting of repeated Wingate tests over a 2- to 3-week period. Subjects completed 4 Wingate tests on days 1 and 2, 5 on days 3 and 4, and 6 on days 5 and 6. A control group of 9 men and women (age and body fat = 22.8 ± 2.8 years and 15.2 ± 6.9%) completed all testing but did not perform HIIT. Changes in resting blood pressure (BP) and heart rate (HR), VO2max, body composition, oxygen (O2) pulse, peak, mean, and minimum power output, fatigue index, and voluntary force production of the knee flexors and extensors were examined pretraining and posttraining. Results showed significant (p < 0.05) improvements in VO2max, O2 pulse, and Wingate-derived power output with HIIT. The magnitude of improvement in VO2max was related to baseline VO2max (r = -0.44, p = 0.05) and fatigue index (r = 0.50, p < 0.05). No change (p > 0.05) in resting BP, HR, or force production was revealed. Data show that HIIT significantly enhanced VO2max and O2 pulse and power output in active men and women.
Briefly delayed reinforcement effects on variable-ratio and yoked-interval schedule performance.
Holtyn, August F; Lattal, Kennon A
2013-09-01
Most investigations of briefly delayed reinforcement have involved schedules that arrange a time-plus-response requirement. The present experiment examined whether briefly delaying reinforcement on schedules that have a ratio requirement differs from results with schedules that have a time-plus-response requirement. Four pigeons responded on a two-component multiple schedule. One component arranged a variable-ratio (VR) 50 and the other a variable-interval (VI) schedule in which the distribution of reinforcers was yoked to the preceding VR schedule. Across a series of conditions, delays were imposed in both schedules. These delays were brief (0.25- or 0.5-s) unsignaled delays and, as control conditions, a 5-s unsignaled delay and a 0.5-s delay signaled by a blackout of the chamber. In the yoked-VI component, the brief unsignaled delay increased response rates in six of nine opportunities and increased the proportion of short interresponse times (IRTs) (<0.4 s) in eight of nine opportunities. In the VR component, the brief unsignaled delay increased response rates and the proportion of short IRTs in only two of nine opportunities. For two of the three pigeons that were exposed to the 5-s unsignaled delay, response rates and the proportion of short IRTs decreased in both of the components. The 0.5-s signaled delay did not systematically change response rates nor did it change the distribution of short IRTs relative to the immediate reinforcement condition. The results replicate effects reported with time-based schedules and extend these observations by showing that changes commonly observed in VI performance with briefly delayed reinforcement are not characteristic of VR responding.
Effects of rest intervals and training loads on metabolic stress and muscle hypertrophy.
Fink, Julius; Kikuchi, Naoki; Nakazato, Koichi
2016-12-28
We investigated the effects of volume-matched resistance training (RT) with different training loads and rest intervals on acute responses and long-term muscle and strength gains. Ten subjects trained with short rest (30 s) combined with low load (20 RM) (SL) and ten subjects performed the same protocol with long rest (3 min) and high load (8 RM) (LH). Cross-sectional area (CSA) of the upper arm was measured by magnetic resonance imaging before and after 8 weeks of training. Acute stress markers such as growth hormone (GH) and muscle thickness (MT) changes have been assessed pre and post a single RT session. Only the SL group demonstrated significant increases in GH (7704·20 ± 11833·49%, P<0·05) and MT (35·2 ± 16·9%, P<0·05) immediately after training. After 8 weeks, the arm CSA s in both groups significantly increased [SL: 9·93 ± 4·86% (P<0·001), LH: 4·73 ± 3·01% (P<0·05)]. No significant correlation between acute GH elevations and CSA increases could be observed. We conclude that short rest combined with low-load training might induce a high amount of metabolic stress ultimately leading to improved muscle hypertrophy while long rest with high-load training might lead to superior strength increases. Acute GH increases seem not to be directly correlated with muscle hypertrophy. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.
von Gillhaussen, Philipp; Rascher, Uwe; Jablonowski, Nicolai D; Plückers, Christine; Beierkuhnlein, Carl; Temperton, Vicky M
2014-01-01
Priority effects occur when species that arrive first in a habitat significantly affect the establishment, growth, or reproduction of species arriving later and thus affect functioning of communities. However, we know little about how the timing of arrival of functionally different species may alter structure and function during assembly. Even less is known about how plant density might interact with initial assembly. In a greenhouse experiment legumes, grasses or forbs were sown a number of weeks before the other two plant functional types were sown (PFT) in combination with a sowing density treatment. Legumes, grasses or non-legume forbs were sown first at three different density levels followed by sowing of the remaining PFTs after three or six-weeks. We found that the order of arrival of different plant functional types had a much stronger influence on aboveground productivity than sowing density or interval between the sowing events. The sowing of legumes before the other PFTs produced the highest aboveground biomass. The larger sowing interval led to higher asymmetric competition, with highest dominance of the PFT sown first. It seems that legumes were better able to get a head-start and be productive before the later groups arrived, but that their traits allowed for better subsequent establishment of non-legume PFTs. Our study indicates that the manipulation of the order of arrival can create priority effects which favour functional groups of plants differently and thus induce different assembly routes and affect community composition and functioning.
Lewis, Evan J H; Stucky, Frédéric; Radonic, Peter W; Metherel, Adam H; Wolever, Thomas M S; Wells, Greg D
2017-03-01
Sprint interval training (SIT) stimulates rapid metabolic adaptations within skeletal muscle but the nature of neuromuscular adaptions is unknown. Omega-3 polyunsaturated fatty acids (N-3 PUFA) are suggested to enhance neuromuscular adaptations to exercise. We measured the neuromuscular adaptations to SIT (Study-1) and conducted a placebo-controlled randomized double blinded study to determine the effect of N-3 PUFA supplementation on neuromuscular adaptations to SIT (Study-2). In Study-1, seven active men (24.4 ± 2.6 years, VO2 peak 43.8 ± 8.7 ml kg min(-1)) completed 2-weeks of SIT with pre- and post-training 10 km cycling time trials (TT). In Study-2, 30 active men (24.5 ± 4.2 years, VO2 peak 41.0 ± 5.1 ml kg min(-1)) were randomly assigned to receive N-3 PUFA (2330 mg day(-1)) (n = 14) or olive oil (n = 16) during 2-weeks of SIT with pre- and post-training TTs. Four week post-training, a SIT session and TT were also performed. Change in neuromuscular function was assessed from resting twitches, quadriceps maximal voluntary contraction (MVC) force, and potentiated twitch force (Q tw). Study-1 showed that SIT did not elicit significant neuromuscular adaptations. Study-2 showed that N-3 PUFA supplementation had no significant effect on neuromuscular adaptations. Training caused lower MVC force [mean ± SD; N-3 PUFA -9 ± 11%, placebo -9 ± 13% (p < 0.05 time)] and Q tw peripheral fatigue [N-3 PUFA -10 ± 19%, placebo -14 ± 13% (p < 0.05 time)]. TT time was lower after training in all groups [Study-1 -10%, Study-2 N-3 PUFA -8%, placebo -12% (p < 0.05 time)]. Two weeks of SIT improved TT performance in the absence of measurable neuromuscular adaptations. N-3 PUFA supplementation had no significant effect on SIT training adaptations.
NASA Astrophysics Data System (ADS)
Fang, Chih-Chiang; Yeh, Chun-Wu
2016-09-01
The quantitative evaluation of software reliability growth model is frequently accompanied by its confidence interval of fault detection. It provides helpful information to software developers and testers when undertaking software development and software quality control. However, the explanation of the variance estimation of software fault detection is not transparent in previous studies, and it influences the deduction of confidence interval about the mean value function that the current study addresses. Software engineers in such a case cannot evaluate the potential hazard based on the stochasticity of mean value function, and this might reduce the practicability of the estimation. Hence, stochastic differential equations are utilised for confidence interval estimation of the software fault-detection process. The proposed model is estimated and validated using real data-sets to show its flexibility.
Al-Jasmi, Fatima; Al-Mansoor, Fatima; Alsheiba, Aisha; Carter, Anne O.; Carter, Thomas P.; Hossain, M. Moshaddeque
2002-01-01
OBJECTIVE: To investigate whether a short interpregnancy interval is a risk factor for preterm birth in Emirati women, where there is a wide range of interpregnancy intervals and uniformity in potentially confounding factors. METHODS: A case-control design based on medical records was used. A case was defined as a healthy multiparous Emirati woman delivering a healthy singleton spontaneously before 37 weeks of gestation between 1997 and 2000, and a control was defined as the next eligible similar woman delivering after 37 weeks of gestation. Women were excluded if there was no information available about their most recent previous pregnancy or if it had resulted in a multiple or preterm birth. Data collected from charts and delivery room records were analysed using the STATA statistical package. All variables found to be valid, stable and significant by univariate analysis were included in multivariate logistic regression analysis. FINDINGS: There were 128 cases who met the eligibility criteria; 128 controls were selected. Short interpregnancy intervals were significantly associated with case status (P<0.05). The multivariate adjusted odds ratios for the 1st, 2nd, and 4th quartiles of interpregnancy interval compared with the lowest-risk 3rd quartile were 8.2, 5.4, and 2.0 (95% confidence intervals: 3.5-19.2, 2.4-12.6, and 0.9- 4.5 respectively). CONCLUSION: A short interpregnancy interval is a risk factor for spontaneous preterm birth in Emirati women. The magnitude of the risk and the risk gradient between exposure quartiles suggest that the risk factor is causal and that its modification would reduce the risk of preterm birth. PMID:12481208
Effects of sampling standardization on estimates of Phanerozoic marine diversification
Alroy, J.; Marshall, C. R.; Bambach, R. K.; Bezusko, K.; Foote, M.; Fürsich, F. T.; Hansen, T. A.; Holland, S. M.; Ivany, L. C.; Jablonski, D.; Jacobs, D. K.; Jones, D. C.; Kosnik, M. A.; Lidgard, S.; Low, S.; Miller, A. I.; Novack-Gottshall, P. M.; Olszewski, T. D.; Patzkowsky, M. E.; Raup, D. M.; Roy, K.; Sepkoski, J. J.; Sommers, M. G.; Wagner, P. J.; Webber, A.
2001-01-01
Global diversity curves reflect more than just the number of taxa that have existed through time: they also mirror variation in the nature of the fossil record and the way the record is reported. These sampling effects are best quantified by assembling and analyzing large numbers of locality-specific biotic inventories. Here, we introduce a new database of this kind for the Phanerozoic fossil record of marine invertebrates. We apply four substantially distinct analytical methods that estimate taxonomic diversity by quantifying and correcting for variation through time in the number and nature of inventories. Variation introduced by the use of two dramatically different counting protocols also is explored. We present sampling-standardized diversity estimates for two long intervals that sum to 300 Myr (Middle Ordovician-Carboniferous; Late Jurassic-Paleogene). Our new curves differ considerably from traditional, synoptic curves. For example, some of them imply unexpectedly low late Cretaceous and early Tertiary diversity levels. However, such factors as the current emphasis in the database on North America and Europe still obscure our view of the global history of marine biodiversity. These limitations will be addressed as the database and methods are refined. PMID:11353852
Woodruff-Pak, Diana S.; Seta, Susan E.; Roker, LaToya A.; Lehr, Melissa A.
2007-01-01
The aim of this study was to examine parameters affecting age differences in eyeblink classical conditioning in a large sample of young and middle-aged rabbits. A total of 122 rabbits of mean ages of 4 or 26 mo were tested at inter-stimulus intervals (ISIs) of 600 or 750 msec in the delay or trace paradigms. Paradigm affected both age groups dramatically, with superior performance in the delay paradigm. ISI was salient as middle-aged rabbits were significantly impaired in 750-msec compared with 600-msec delays, and young rabbits were significantly less impaired in 600-msec than in 750-msec trace. Young rabbits performed equally well at both delay ISIs, and consequently, there were significant age differences in 750-msec but not in 600-msec delays. Middle-aged rabbits performed poorly at both 600- and 750-msec trace, resulting in significant age differences in 600-msec but not in 750-msec trace. Timing of the conditioned response has been associated with cerebellar cortical function. Normal aging of the cerebellar cortex likely contributed to the magnitude of the effect of ISI in delay conditioning in middle-aged rabbits. Results demonstrate that the magnitude of age differences in eyeblink conditioning can be enlarged or eliminated by ISI and paradigm. PMID:17522017
Schulz, Sebastian Viktor Waldemar; Laszlo, Roman; Otto, Stephanie; Prokopchuk, Dmytro; Schumann, Uwe; Ebner, Florian; Huober, Jens; Steinacker, Jürgen Michael
2017-03-21
To evaluate feasibility of an exercise intervention consisting of high-intensity interval endurance and strength training in breast cancer patients. Twenty-six women with nonmetastatic breast cancer were consecutively assigned to the exercise intervention- (n= 15, mean age 51.9 ± 9.8 years) and the control group (n = 11, mean age 56.9 ± 7.0 years). Cardiopulmonary exercise testing that included lactate sampling, one-repetition maximum tests and a HADS-D questionnaire were used to monitor patients both before and after a supervised six weeks period of either combined high-intensity interval endurance and strength training (intervention group, twice a week) or leisure training (control group). Contrarily to the control group, endurance (mean change of VO2, peak 12.0 ± 13.0%) and strength performance (mean change of cumulative load 25.9 ± 11.2%) and quality of life increased in the intervention group. No training-related adverse events were observed. Our guided exercise intervention could be used effectively for initiation and improvement of performance capacity and quality of life in breast cancer patients in a relatively short time. This might be especially attractive during medical treatment. Long-term effects have to be evaluated in randomized controlled studies also with a longer follow-up. Implications for Rehabilitation High-intensity interval training allows improvement of aerobic capacity within a comparable short time. Standard leisure training in breast cancer patients is rather suitable for the maintenance of performance capacity and quality of life. Guided high-intensity interval training combined with strength training can be used effectively for the improvement of endurance and strength capacity and also quality of life. After exclusion of contraindications, guided adjuvant high-intensity interval training combined with strength training can be safely used in breast cancer patients.
Cirincione, Brenda; LaCreta, Frank; Sager, Philip; Mager, Donald E
2017-08-01
Investigation of the cardiovascular proarrhythmic potential of a new chemical entity is now an integral part of drug development. Studies suggest that meals and glycemic changes can influence QT intervals, and a semimechanistic model has been developed that incorporates the effects of changes in glucose concentrations on heart rate (HR) and QT intervals. This analysis aimed to adapt the glucose-HR-QT model to incorporate the effects of exenatide, a drug that reduces postprandial increases in glucose concentrations. The final model includes stimulatory drug effects on glucose elimination and HR perturbations. The targeted and constant exenatide plasma concentrations (>200 pg/mL), via intravenous infusions at multiple dose levels, resulted in significant inhibition of glucose concentrations. The exenatide concentration associated with 50% of the stimulation of HR production was 584 pg/mL. After accounting for exenatide effects on glucose and HR, no additional drug effects were required to explain observed changes in the QT interval. Resulting glucose, HR, and QT profiles at all exenatide concentrations were adequately described. For therapeutic agents that alter glycemic conditions, particularly those that alter postprandial glucose, the QT interval cannot be directly compared to that with placebo without first accounting for confounding factors (eg, glucose) either through mathematical modeling or careful consideration of mealtime placement in the study design. © 2017, The Authors. The Journal of Clinical Pharmacology published by Wiley Periodicals, Inc. on behalf of American College of Clinical Pharmacology.
LaCreta, Frank; Sager, Philip; Mager, Donald E.
2017-01-01
Abstract Investigation of the cardiovascular proarrhythmic potential of a new chemical entity is now an integral part of drug development. Studies suggest that meals and glycemic changes can influence QT intervals, and a semimechanistic model has been developed that incorporates the effects of changes in glucose concentrations on heart rate (HR) and QT intervals. This analysis aimed to adapt the glucose‐HR‐QT model to incorporate the effects of exenatide, a drug that reduces postprandial increases in glucose concentrations. The final model includes stimulatory drug effects on glucose elimination and HR perturbations. The targeted and constant exenatide plasma concentrations (>200 pg/mL), via intravenous infusions at multiple dose levels, resulted in significant inhibition of glucose concentrations. The exenatide concentration associated with 50% of the stimulation of HR production was 584 pg/mL. After accounting for exenatide effects on glucose and HR, no additional drug effects were required to explain observed changes in the QT interval. Resulting glucose, HR, and QT profiles at all exenatide concentrations were adequately described. For therapeutic agents that alter glycemic conditions, particularly those that alter postprandial glucose, the QT interval cannot be directly compared to that with placebo without first accounting for confounding factors (eg, glucose) either through mathematical modeling or careful consideration of mealtime placement in the study design. PMID:28543393
Confidence Intervals for an Effect Size Measure in Multiple Linear Regression
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.; Penfield, Randall D.
2007-01-01
The increase in the squared multiple correlation coefficient ([Delta]R[squared]) associated with a variable in a regression equation is a commonly used measure of importance in regression analysis. The coverage probability that an asymptotic and percentile bootstrap confidence interval includes [Delta][rho][squared] was investigated. As expected,…
Confidence Intervals for an Effect Size Measure in Multiple Linear Regression
ERIC Educational Resources Information Center
Algina, James; Keselman, H. J.; Penfield, Randall D.
2007-01-01
The increase in the squared multiple correlation coefficient ([Delta]R[squared]) associated with a variable in a regression equation is a commonly used measure of importance in regression analysis. The coverage probability that an asymptotic and percentile bootstrap confidence interval includes [Delta][rho][squared] was investigated. As expected,…
The Effect of Different Musical Timbres on Students' Identification of Melodic Intervals.
ERIC Educational Resources Information Center
Hinton, Dallas E.
For this study, five hypotheses were formulated stating that ability to identify melodic intervals during music dictation is not affected by (1) the differences in timbre, (2) the use of familiar or unfamiliar timbres (MAJOR), (3) formal ear training experience (FETE), or (4) playing/performing experience on an instrument (PPEM), and (5) that…
Effects of Length of Retention Interval on Proactive Interference in Short-Term Visual Memory
ERIC Educational Resources Information Center
Meudell, Peter R.
1977-01-01
These experiments show two things: (a) In visual memory, long-term interference on a current item from items previously stored only seems to occur when the current item's retention interval is relatively long, and (b) the visual code appears to decay rapidly, reaching asymptote within 3 seconds of input in the presence of an interpolated task.…
NASA Technical Reports Server (NTRS)
Chiavassa, G.; Liandrat, J.
1996-01-01
We construct compactly supported wavelet bases satisfying homogeneous boundary conditions on the interval (0,1). The maximum features of multiresolution analysis on the line are retained, including polynomial approximation and tree algorithms. The case of H(sub 0)(sup 1)(0, 1)is detailed, and numerical values, required for the implementation, are provided for the Neumann and Dirichlet boundary conditions.
Practice effects on the WAIS-III across 3- and 6-month intervals.
Basso, Michael R; Carona, Francine D; Lowery, Natasha; Axelrod, Bradley N
2002-02-01
Fifty-one participants (age M = 24.6; education M = 14.4 years) were administered the Wechsler Adult Intelligence Scale - Third Edition (WAIS-III) at baseline and at an interval of either 3 or 6 months later. Full Scale IQ (FSIQ), Verbal IQ (VIQ), Performance IQ (PIQ), Verbal Comprehension Index (VCI), Perceptual Organization Index (POI), and Processing Speed Index (PSI) scores improved significantly across time, whereas no significant change occurred on the Working Memory Index. Specifically, test scores increased approximately 3, 11, 6, 4, 8, and 7 points, respectively on the VIQ, PIQ, FSIQ, VCI, POI, and PSI for both groups. Notably, the degree of improvement was similar regardless of whether the inter-test interval was 3 or 6 months. These findings suggest that prior exposure to the WAIS-III yields considerable increases in test scores. Reliable change indices indicated that large confidence intervals might be expected. As such, users of the WAIS-III should interpret reevaluations across these intervals cautiously.
Pahuja, Rasleen Kaur; Garg, Sandeep; Bansal, Sanjay; Dang, Rajat Harvinder
2013-08-01
This study was aimed to determine the effect of two chemically distinct denture cleansers and water on the surface hardness of acrylic and silicone based soft denture liners at various time intervals. Two commonly used commercial resilient liner material were selected based on their chemical composition (silicone- and acrylic-based soft liners) for this investigation. 120 cylindrical specimens were made of 15 mm × 10 mm dimensions (according to ASTM: D-2240-64T) in a custom made metal mold. All specimens were stored in artificial saliva throughout the study. Forty specimens were cleansed daily in 0.5% sodium hypochlorite solution; forty were cleansed in sodium perborate and remaining forty specimens were daily rinsed in water. Testing was done at 1 week, 1 month, 3 months and 6 months for surface hardness using a Shore A Durometer. A mean of 3 reading for each sample was subjected to one-way ANOVA, Post Hoc test and pair-t test for statistical analysis. P values of less than 0.05 were taken as statistically significant. Surface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Minor changes were observed between control, sodium hypochlorite and sodium perborate groups with time. Greater change was observed in surface hardness of acrylic-based soft denture liners as compared to silicone-based soft liners for all groups, as time progressed. Silicone-based soft denture liners performed significantly better in all cleansing treatments than acrylic-based soft denture liners.
Pahuja, Rasleen Kaur; Bansal, Sanjay
2013-01-01
PURPOSE This study was aimed to determine the effect of two chemically distinct denture cleansers and water on the surface hardness of acrylic and silicone based soft denture liners at various time intervals. MATERIALS AND METHODS Two commonly used commercial resilient liner material were selected based on their chemical composition (silicone- and acrylic-based soft liners) for this investigation. 120 cylindrical specimens were made of 15 mm × 10 mm dimensions (according to ASTM: D-2240-64T) in a custom made metal mold. All specimens were stored in artificial saliva throughout the study. Forty specimens were cleansed daily in 0.5% sodium hypochlorite solution; forty were cleansed in sodium perborate and remaining forty specimens were daily rinsed in water. Testing was done at 1 week, 1 month, 3 months and 6 months for surface hardness using a Shore A Durometer. A mean of 3 reading for each sample was subjected to one-way ANOVA, Post Hoc test and pair-t test for statistical analysis. P values of less than 0.05 were taken as statistically significant. RESULTS Surface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Minor changes were observed between control, sodium hypochlorite and sodium perborate groups with time. Greater change was observed in surface hardness of acrylic-based soft denture liners as compared to silicone-based soft liners for all groups, as time progressed. CONCLUSION Silicone-based soft denture liners performed significantly better in all cleansing treatments than acrylic-based soft denture liners. PMID:24049568
Edge Effects in Line Intersect Sampling With
David L. R. Affleck; Timothy G. Gregoire; Harry T. Valentine
2005-01-01
Transects consisting of multiple, connected segments with a prescribed configuration are commonly used in ecological applications of line intersect sampling. The transect configuration has implications for the probability with which population elements are selected and for how the selection probabilities can be modified by the boundary of the tract being sampled. As...
Siniscalchi, Antonio; Scaglione, Francesco; Sanzaro, Enzo; Iemolo, Francesco; Albertini, Giorgio; Quirino, Gianluca; Manes, Maria Teresa; Gratteri, Santo; Mercuri, Nicola Biagio; De Sarro, Giovambattista; Gallelli, Luca
2014-12-01
Sudden unexplained/unexpected death (SUDEP) is related to high mortality in patients with epilepsy. The prolongation of QT interval, involved in cardiac arrhythmia-related SUDEP, may be precipitated by antiepileptic drugs (AEDs). In this study, we evaluated the effects of phenobarbital and levetiracetam on PR-QTc intervals in patients with post-stroke seizures. We performed an open-label, parallel group, prospective, multicenter study between June 2009 and December 2013 in patients older than 18 years of age with a clinical diagnosis of post-stroke seizure and treated with phenobarbital or levetiracetam. In order to exclude a role of cerebral post-stroke injury on modulation of PR and QTc intervals, patients with cerebral post-stroke injury and without seizures were also enrolled as controls. Interictal electrocardiography analysis revealed no significant difference in PR interval between patients treated with an AED (n = 49) and control patients (n = 50) (181.25 ± 12.05 vs. 182.4 ± 10.3 ms; p > 0.05). In contrast, a significantly longer QTc interval was recorded in patients treated with an AED compared with control patients (441.2 ± 56.6 vs. 396.8 ± 49.3 ms; p < 0.01). Patients treated with phenobarbital showed a significantly longer QTc interval than patients treated with levetiracetam (460.0 ± 57.2 vs. 421.5 ± 50.1 ms; p < 0.05). The study reported that in patients with late post-stroke seizures, phenobarbital prolonged QTc interval more so than levetiracetam.
ERIC Educational Resources Information Center
Davidow, Jason H.; Ingham, Roger J.
2013-01-01
Purpose: This study examined the effect of speech rate on phonated intervals (PIs), in order to test whether a reduction in the frequency of short PIs is an important part of the fluency-inducing mechanism of chorus reading. The influence of speech rate on stuttering frequency, speaker-judged speech effort, and listener-judged naturalness was also…
ERIC Educational Resources Information Center
Odgaard, Eric C.; Fowler, Robert L.
2010-01-01
Objective: In 2005, the "Journal of Consulting and Clinical Psychology" ("JCCP") became the first American Psychological Association (APA) journal to require statistical measures of clinical significance, plus effect sizes (ESs) and associated confidence intervals (CIs), for primary outcomes (La Greca, 2005). As this represents the single largest…
ERIC Educational Resources Information Center
Kral, Paul A.; And Others
Investigates the effect of delay of reinforcement upon human discrimination learning with particular emphasis on the form of the gradient within the first few seconds of delay. In previous studies subjects are usually required to make an instrumental response to a stimulus, this is followed by the delay interval, and finally, the reinforcement…
ERIC Educational Resources Information Center
Davidow, Jason H.; Ingham, Roger J.
2013-01-01
Purpose: This study examined the effect of speech rate on phonated intervals (PIs), in order to test whether a reduction in the frequency of short PIs is an important part of the fluency-inducing mechanism of chorus reading. The influence of speech rate on stuttering frequency, speaker-judged speech effort, and listener-judged naturalness was also…
ERIC Educational Resources Information Center
Odgaard, Eric C.; Fowler, Robert L.
2010-01-01
Objective: In 2005, the "Journal of Consulting and Clinical Psychology" ("JCCP") became the first American Psychological Association (APA) journal to require statistical measures of clinical significance, plus effect sizes (ESs) and associated confidence intervals (CIs), for primary outcomes (La Greca, 2005). As this represents the single largest…
Shepherd, Timothy M; Flint, Jeremy J; Thelwall, Peter E; Stanisz, Greg J; Mareci, Thomas H; Yachnis, Anthony T; Blackband, Stephen J
2009-02-01
High-resolution imaging of human autopsy tissues may improve our understanding of in vivo MRI findings, but interpretation is complicated because samples are obtained by immersion fixation following a postmortem interval (PMI). This study tested the hypotheses that immersion fixation and PMI's from 0-24 h would alter the water relaxation and diffusion properties in rat cortical slice and spinal cord models of human nervous tissue. Diffusion data collected from rat cortical slices at multiple diffusion times (10-60 ms) and b-values (7-15,000 s/mm(2)) were analyzed using a two-compartment model with exchange. Rat spinal cords were characterized with standard diffusion tensor imaging (21 directions, b=1250 s/mm(2)). Switching from perfusion- to immersion-fixation at 0 h PMI altered most MRI properties of rat cortical slices and spinal cords, including a 22% decrease in fractional anisotropy (P<0.001). After 4 h PMI, cortical slice T(1) and T(2) increased 22% and 65% respectively (P<0.001), transmembrane water exchange decreased 23% (P<0.001) and intracellular proton fraction increased 25% (P=0.002). After 6 h PMI, spinal cord white matter fractional anisotropy had decreased 38% (P<0.001). MRI property changes were observed for PMIs up to 24 h. The MRI changes correlated with protease activity and histopathological signs of autolysis. Thus, immersion fixation and/or even short PMIs (4-6 h) altered the MRI properties of rat nervous tissue. This suggests comparisons between in vivo clinical MRI and MRI data from human autopsy tissues should be interpreted with caution.
Steiner, Genevieve Z.; Barry, Robert J.; Gonsalvez, Craig J.
2016-01-01
In oddball tasks, increasing the time between stimuli within a particular condition (target-to-target interval, TTI; nontarget-to-nontarget interval, NNI) systematically enhances N1, P2, and P300 event-related potential (ERP) component amplitudes. This study examined the mechanism underpinning these effects in ERP components recorded from 28 adults who completed a conventional three-tone oddball task. Bivariate correlations, partial correlations and multiple regression explored component changes due to preceding ERP component amplitudes and intervals found within the stimulus series, rather than constraining the task with experimentally constructed intervals, which has been adequately explored in prior studies. Multiple regression showed that for targets, N1 and TTI predicted N2, TTI predicted P3a and P3b, and Processing Negativity (PN), P3b, and TTI predicted reaction time. For rare nontargets, P1 predicted N1, NNI predicted N2, and N1 predicted Slow Wave (SW). Findings show that the mechanism is operating on separate stages of stimulus-processing, suggestive of either increased activation within a number of stimulus-specific pathways, or very long component generator recovery cycles. These results demonstrate the extent to which matching-stimulus intervals influence ERP component amplitudes and behavior in a three-tone oddball task, and should be taken into account when designing similar studies. PMID:27445774
Machado, Marco; Koch, Alexander J; Willardson, Jeffrey M; Pereira, Luis S; Cardoso, M Isabel; Motta, Michela K S; Pereira, Rafael; Monteiro, André N
2011-05-01
To examine the effects of different rest intervals between sets on serum creatine kinase (CK) and lactate dehydrogenase (LDH) activity, 10 men (age = 25.6 ± 2.2 years, height = 173.1 ± 7.1 cm, and body mass = 75.9 ± 10.0 kg) participated in a randomized within-subject design that involved 4 resistance exercise sessions. Each session consisted of 4 sets of 10 repetitions with 10 repetition maximum loads for the chest press, pullover, biceps curl, triceps extension, leg extension, and prone leg curl. The sessions differed only in the length of the rest interval between sets and exercises, specifically: 60, 90, 120, 180 seconds. Serum CK and LDH were significantly (p < 0.05) elevated 24-72 hours after each session, with no significant differences between rest intervals (p = 0.94 and p = 0.99, respectively). The mechanical stress imposed by the 4 resistance exercise sessions invoked similar damage to the muscle fibers independent of the rest interval between sets. These data indicate that the accumulated volume of work is the primary determinant of muscle damage in trained subjects who are accustomed to resistance exercise with short rest intervals.
Pierson, J; Wang, B; Neveu, N; Sneek, L; Côté, F; Karatzas, C N; Baldassarre, H
2004-01-01
The present study was conducted to evaluate the follicular response and oocyte yield following repeated gonadotrophin stimulation and laparoscopic aspiration in goats and to assess the effects of the time interval between procedures and season. A total of 98 adult goats were subjected to laparoscopic ovum pick-up (LOPU) five consecutive times in a transgenic production programme. Oestrus was synchronised by means of intravaginal sponges inserted for 10 days coupled with 125 microg cloprostenol 36 h before sponge removal and LOPU, and follicular development was stimulated with 80 mg follicle stimulating hormone and 300 IU equine chorionic gonadotrophin administered 36 h before LOPU. No difference was detected in the response for LOPUs 1, 2, 3 and 4. Although a small decrease in response was detected at LOPU 5 (P < 0.05), the numbers of follicles aspirated and oocytes recovered were not different from those at LOPU 1 and LOPUs 1 and 4, respectively. With respect to time interval between LOPU and season, all intervals and seasons produced acceptable responses, with no difference in follicles aspirated and oocytes recovered between intervals and seasons. These results indicate that LOPU may be repeated up to five times in goats at different intervals and in different seasons with little or no important change in overall response.
Santos, E M; Pereira, O G; Garcia, R; Ferreira, C L L F; Oliveira, J S; Silva, T C
2014-07-01
The objectives of this study were to characterize and quantify the microbial populations in guinea grass (Panicum maximum Jacq. cultivar Mombasa) harvested at different regrowth intervals (35, 45, 55, and 65 d). The chemical composition and fermentation profile of silages (after 60 d) with or without the addition of a microbial inoculant were also analyzed. Before ensiling, samples of the plants were used for the isolation and identification of lactic acid bacteria (LAB) in the epiphytic microbiota. A 4 × 2 factorial arrangement of treatments (4 regrowth intervals × with/without inoculant) was used in a completely randomized design with 3 replications. Based on the morphological and biochemical characteristics and the carbohydrate fermentation profile, Lactobacillus plantarum was found to be the predominant specie of LAB in guinea grass forage. Linear increases were detected in the dry matter (DM) content and concentrations of neutral detergent fiber, acid detergent fiber, acid detergent insoluble nitrogen, and DM recovery as well as linear reductions in the concentrations of crude protein and NH3-N with regrowth interval. Additionally, linear reductions for gas and effluent losses in silages were detected with increasing regrowth interval. These results demonstrate that guinea grass plants harvested after 55 d of regrowth contain a LAB population sufficiently large to ensure good fermentation and increase the DM recovery. The use of microbial inoculant further enhanced the fermentation of guinea grass at all stages of regrowth by improving the DM recovery.
Cavus, H A; Msetfi, Rachel M
2016-11-01
When there is no contingency between actions and outcomes, but outcomes occur frequently, people tend to judge that they have control over those outcomes, a phenomenon known as the outcome density (OD) effect. Recent studies show that the OD effect depends on the duration of the temporal interval between action-outcome conjunctions, with longer intervals inducing stronger effects. However, under some circumstances OD effect is reduced, for example when participants are mildly depressed. We reasoned that working memory (WM) plays an important role in learning of context; with reduced WM capacity to process contextual information during intertrial intervals (ITIs) during contingency learning might lead to reduced OD effects (limited capacity hypothesis). To test this, we used a novel dual-task procedure that increases the WM load during the ITIs of an operant (e.g., action-outcome) contingency learning task to impact contextual learning. We tested our hypotheses in groups of students with zero (Experiments 1, N=34), and positive contingencies (Experiment 2, N=34). The findings indicated that WM load during the ITIs reduced the OD effects compared to no load conditions (Experiment 1 and 2). In Experiment 2, we observed reduced OD effects on action judgements under high load in zero and positive contingencies. However, the participants' judgements were still sensitive to the difference between zero and positive contingencies. We discuss the implications of our findings for the effects of depression and context in contingency learning.
Keller, John V.; Van Der Schoot, Frank
1978-01-01
Two groups of pigeons were exposed to a simple reaction-time procedure in which mean foreperiod duration was 5, 10, or 20 seconds. For one group, the foreperiods had an arithmetic, or rectangular, distribution; for the second group, they had a constant-probability, or Bernoulli, distribution. Under both distributions, mean response latency was an increasing, negatively accelerated function of mean foreperiod duration. On a given trial, response latency was a function of its associated foreperiod duration: latency was a decreasing function of foreperiod duration in the arithmetic distribution, and an increasing function of foreperiod duration in the constant-probability distribution. Examination of the distribution of latencies revealed a harmonic structure reminiscent of distributions of interresponse times under variable-interval schedules of reinforcement. Taken together, the results confirm and extend previous findings with human subjects, and also suggest numerous similarities to behavior maintained by variable-interval schedules. PMID:16812084
DaVanzo, Julie; Hale, Lauren; Razzaque, Abdur; Rahman, Mizanur
2008-07-01
Using high-quality longitudinal data on 125,720 singleton live births in Matlab, Bangladesh, we assessed the effects of duration of intervals between pregnancy outcomes on infant and child mortality and how these effects vary over subperiods of infancy and childhood and by the type of outcome that began the interval. Controlling for other correlates of infant and child mortality, we find that shorter intervals are associated with higher mortality. Interval effects are greater if the interval began with a live birth than with another pregnancy outcome. In the first week of the child's life, the effects of short intervals are greater if the sibling born at the beginning of the interval died; after the first month, the effects are greater if that sibling was still alive. Many relationships found are consistent with the maternal depletion hypothesis, and some with sibling competition. Some appear to be due to correlated risks among births to the same mother.
Reproducibility of the systolic time intervals: effect of the temporal range of measurements.
Kupari, M
1983-06-01
The aim of this study was to evaluate the reproducibility of conventionally measured systolic time intervals. To that end, three to eight serial measurements were performed on four different groups of healthy subjects (total number, 49) within dissimilar time periods: 1) within 3 h; 2) within 24 h; 3) within 1 to 2 weeks; and 4) within 14 to 18 months. Judged as the mean coefficients of variation, the variability of the systolic time intervals tended to be smallest in the 3 h measurements and largest in the 24 h measurements. The pooled variances of the serial measurements made within 24 h were in general significantly larger than the respective variances in the measurements made within 3 h. This was due to statistically significant diurnal decreases in left ventricular ejection time and total electromechanic systole in the 24 h study. Otherwise the reproducibility of the method was high. For instance, the mean coefficients of variation for ejection time and total electromechanic systole corrected for heart rate were only 1% and 1.2%, respectively, in serial measurements made at identical diurnal time points within 14 to 18 months. The pooled variances of the measurements made within the shortest and longest temporal ranges were not statistically different. It is concluded that measurement of the systolic time intervals is very applicable to intervention and follow-up studies provided the normal circadian rhythmicity of the phases of systole is adequately taken into account in the design of the study.
Quintans, G; Vázquez, A I; Weigel, K A
2009-11-01
Suckling and nutrition are generally recognized as two major factors controlling the duration of the postpartum anovulatory period. In the present study, the effect of premature weaning and suckling restriction with nose plates (NPs) on cow and calf performance was evaluated. The study was conducted over 2 years; primiparous Hereford cows, weighing (mean+/-S.E.M.) 344+/-3.5kg and with 4.1+/-0.05 units of body condition score (BCS) (scale 1-8 [Vizcarra, J.A., Ibañez, W., Orcasberro, R., 1986. Repetibilidad y reproductibilidad de dos escalas para estimar la condición corporal de vacas Hereford. Investigaciones Agronómicas 7 (1), 45-47]) at calving, remained with their calves until 72.5+/-1.2 days postpartum (day 0). They were then assigned to one of three treatments: (i) calves with free access to their dams and ad libitum suckling (S, n=29); (ii) calves fitted with NPs for 14 days, but remained with their dams (NP, n=29), and (iii) calves that were weaned from their dams (W, n=28). All cows were anestrus at the time treatments commenced (day 0). All cows were blood sampled twice weekly from 1 week before the beginning of the experiment until the end of the mating period (day 74) for progesterone analysis. The mating period began on day 14. Cows in W treatment had ovulations earlier (P<0.05) than those in NP and S groups. Cows in the NP group had longer (P<0.05) intervals between the first progesterone increase and normal luteal phase than cows in the other two treatments groups (23.3+/-3.2 vs. 6.5+/-3.2 and 5.2+/-3.3 days for NP, S and W cows, respectively). Fifty per cent of the cows with NP had a short cycle (7 days) but there was a group of cows that had longer (P<0.05) intervals (66 days) between first progesterone increase and normal estrous activity. In the NP group, 8 of 29 cows had a short luteal phase and then a normal one; for 9 of these 29 cows progesterone concentrations remained low for 6 weeks from the beginning of the treatment; and for 12 of these
Radioactive sample effects on EDXRF spectra
Worley, Christopher G
2008-01-01
Energy dispersive X-ray fluorescence (EDXRF) is a rapid, straightforward method to determine sample elemental composition. A spectrum can be collected in a few minutes or less, and elemental content can be determined easily if there is adequate energy resolution. Radioactive alpha emitters, however, emit X-rays during the alpha decay process that complicate spectral interpretation. This is particularly noticeable when using a portable instrument where the detector is located in close proximity to the instrument analysis window held against the sample. A portable EDXRF instrument was used to collect spectra from specimens containing plutonium-239 (a moderate alpha emitter) and americium-241 (a heavy alpha emitter). These specimens were then analyzed with a wavelength dispersive XRF (WDXRF) instrument to demonstrate the differences to which sample radiation-induced X-ray emission affects the detectors on these two types of XRF instruments.
Palmer, Matthew A; Brewer, Neil; Weber, Nathan; Nagesh, Ambika
2013-03-01
Prior research points to a meaningful confidence-accuracy (CA) relationship for positive identification decisions. However, there are theoretical grounds for expecting that different aspects of the CA relationship (calibration, resolution, and over/underconfidence) might be undermined in some circumstances. This research investigated whether the CA relationship for eyewitness identification decisions is affected by three, forensically relevant variables: exposure duration, retention interval, and divided attention at encoding. In Study 1 (N = 986), a field experiment, we examined the effects of exposure duration (5 s vs. 90 s) and retention interval (immediate testing vs. a 1-week delay) on the CA relationship. In Study 2 (N = 502), we examined the effects of attention during encoding on the CA relationship by reanalyzing data from a laboratory experiment in which participants viewed a stimulus video under full or divided attention conditions and then attempted to identify two targets from separate lineups. Across both studies, all three manipulations affected identification accuracy. The central analyses concerned the CA relation for positive identification decisions. For the manipulations of exposure duration and retention interval, overconfidence was greater in the more difficult conditions (shorter exposure; delayed testing) than the easier conditions. Only the exposure duration manipulation influenced resolution (which was better for 5 s than 90 s), and only the retention interval manipulation affected calibration (which was better for immediate testing than delayed testing). In all experimental conditions, accuracy and diagnosticity increased with confidence, particularly at the upper end of the confidence scale. Implications for theory and forensic settings are discussed.
Dadi, Abel Fekadu
2015-01-01
Even though Ethiopia has been celebrating the achievements of MDG 4, still one in every 17 Ethiopian children dies before their first birthday. This is the biggest of the African regional average. Short birth interval is inconsistently reported as a risk factor by limited and independent studies in Ethiopia. Therefore, the purpose of this meta-analysis was to determine the pooled effect size of the preceding birth interval length on infant mortality. Studies were accessed through the electronic web-based search mechanism from PUBMED, Advanced Google Scholar, WHO databases and journals: PLOS ONE, and BMC, using independent and combinations of key terms. Comprehensive meta-analysis version 2 was used to analyze the data. An I2 test was used to assess heterogeneity. Funnel plot and statistical significance by Egger's test of the intercept was used to check publication bias. The final estimate was determined in the form of odds ratio by applying Duval and Tweedie's trim and fill analysis in the Random-effects model. 872 studies were identified on the reviewed topic. During screening, forty-five studies were found to be relevant for data abstraction. However, only five studies fulfilled the inclusion criteria and were included in the analysis. In all of the studies included in the analysis, the preceding birth interval had a significant association with under-one mortality. The final pooled estimate in the form of the odds ratio for infant mortality with a preceding birth interval of less than 24 months was found to be 2.03 (95% CI: 1.52, 2.70, random effect (five studies, n=43,909), I2=70%, P<0.05). In Ethiopia, promoting the length of birth interval to at least two years lowered under-one mortality by 50% (95% CI: 35%, 63%).
Tsitkanou, S; Spengos, K; Stasinaki, A-N; Zaras, N; Bogdanis, G; Papadimas, G; Terzis, G
2016-09-23
Aim of the study was to investigate whether high-intensity interval cycling performed immediately after resistance training would inhibit muscle strength increase and hypertrophy expected from resistance training per se. Twenty-two young men were assigned into either resistance training (RE; N = 11) or resistance training plus high-intensity interval cycling (REC; N = 11). Lower body muscle strength and rate of force development (RFD), quadriceps cross-sectional area (CSA) and vastus lateralis muscle architecture, muscle fiber type composition and capillarization, and estimated aerobic capacity were evaluated before and after 8 weeks of training (2 times per week). Muscle strength and quadriceps CSA were significantly and similarly increased after both interventions. Fiber CSA increased significantly and similarly after both RE (type I: 13.6 ± 3.7%, type IIA: 17.6 ± 4.4%, type IIX: 23.2 ± 5.7%, P < 0.05) and REC (type I: 10.0 ± 2.7%, type IIA: 14.8 ± 4.3% type IIX: 20.8 ± 6.0%, P < 0.05). In contrast, RFD decreased and fascicle angle increased (P < 0.05) only after REC. Capillary density and estimated aerobic capacity increased (P < 0.05) only after REC. These results suggest that high-intensity interval cycling performed after heavy-resistance exercise may not inhibit resistance exercise-induced muscle strength/hypertrophy after 2 months of training, while it prompts aerobic capacity and muscle capillarization. The addition of high-intensity cycling after heavy-resistance exercise may decrease RFD partly due to muscle architectural changes.
van Roon, Aafke H C; Reijerink, Jacqueline C I Y; van Vuuren, Anneke J; Lansdorp-Vogelaar, Iris; Habbema, J Dik F; Kuipers, Ernst J; van Leerdam, Monique E; van Ballegooijen, Marjolein
2013-01-01
Objective The sensitivity and specificity of a single faecal immunochemical test (FIT) are limited. The performance of FIT screening can be improved by increasing the screening frequency or by providing more than one sample in each screening round. This study aimed to evaluate if two-sample FIT screening is cost-effective compared with one-sample FIT. Design The MISCAN–colon microsimulation model was used to estimate costs and benefits of strategies with either one or two-sample FIT screening. The FIT cut-off level varied between 50 and 200 ng haemoglobin/ml, and the screening schedule was varied with respect to age range and interval. In addition, different definitions for positivity of the two-sample FIT were considered: at least one positive sample, two positive samples, or the mean of both samples being positive. Results Within an exemplary screening strategy, biennial FIT from the age of 55–75 years, one-sample FIT provided 76.0–97.0 life-years gained (LYG) per 1000 individuals, at a cost of €259 000–264 000 (range reflects different FIT cut-off levels). Two-sample FIT screening with at least one sample being positive provided 7.3–12.4 additional LYG compared with one-sample FIT at an extra cost of €50 000–59 000. However, when all screening intervals and age ranges were considered, intensifying screening with one-sample FIT provided equal or more LYG at lower costs compared with two-sample FIT. Conclusion If attendance to screening does not differ between strategies it is recommended to increase the number of screening rounds with one-sample FIT screening, before considering increasing the number of FIT samples provided per screening round. PMID:22490518
The effect of sampling technique on PCR-based bacteriological results of bovine milk samples.
Hiitiö, Heidi; Simojoki, Heli; Kalmus, Piret; Holopainen, Jani; Pyörälä, Satu; Taponen, Suvi
2016-08-01
The aim of the study was to evaluate the effect of sampling technique on the microbiological results of bovine milk samples using multiplex real-time PCR. Comparison was made between a technique where the milk sample was taken directly from the udder cistern of the udder quarter using a needle and vacuum tube and conventional sampling. The effect of different cycle threshold (Ct) cutoff limits on the results was also tested to estimate the amount of amplified DNA in the samples. A total of 113 quarters from 53 cows were tested pairwise using both techniques, and each sample was studied with real-time PCR. Sampling from the udder cistern reduced the number of species per sample compared with conventional sampling. In conventional samples, the number of positive Staphylococcus spp. results was over twice that of samples taken with the needle technique, indicating that most of the Staphylococcus spp. originated from the teat or environmental sources. The Ct values also showed that Staphylococcus spp. were present in most samples only in low numbers. Routine use of multiplex real-time PCR in mastitis diagnostics could benefit from critical evaluation of positive Staphylococcus spp. results with Ct values between 34.0 and 37.0. Our results emphasize the importance of a careful aseptic milk sampling technique and a microbiologically positive result for a milk sample should not be automatically interpreted as an intramammary infection or mastitis. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Magnetic Resonance Fingerprinting with short relaxation intervals.
Amthor, Thomas; Doneva, Mariya; Koken, Peter; Sommer, Karsten; Meineke, Jakob; Börnert, Peter
2017-09-01
The aim of this study was to investigate a technique for improving the performance of Magnetic Resonance Fingerprinting (MRF) in repetitive sampling schemes, in particular for 3D MRF acquisition, by shortening relaxation intervals between MRF pulse train repetitions. A calculation method for MRF dictionaries adapted to short relaxation intervals and non-relaxed initial spin states is presented, based on the concept of stationary fingerprints. The method is applicable to many different k-space sampling schemes in 2D and 3D. For accuracy analysis, T1 and T2 values of a phantom are determined by single-slice Cartesian MRF for different relaxation intervals and are compared with quantitative reference measurements. The relevance of slice profile effects is also investigated in this case. To further illustrate the capabilities of the method, an application to in-vivo spiral 3D MRF measurements is demonstrated. The proposed computation method enables accurate parameter estimation even for the shortest relaxation intervals, as investigated for different sampling patterns in 2D and 3D. In 2D Cartesian measurements, we achieved a scan acceleration of more than a factor of two, while maintaining acceptable accuracy: The largest T1 values of a sample set deviated from their reference values by 0.3% (longest relaxation interval) and 2.4% (shortest relaxation interval). The largest T2 values showed systematic deviations of up to 10% for all relaxation intervals, which is discussed. The influence of slice profile effects for multislice acquisition is shown to become increasingly relevant for short relaxation intervals. In 3D spiral measurements, a scan time reduction of 36% was achieved, maintaining the quality of in-vivo T1 and T2 maps. Reducing the relaxation interval between MRF sequence repetitions using stationary fingerprint dictionaries is a feasible method to improve the scan efficiency of MRF sequences. The method enables fast implementations of 3D spatially resolved
Freese, Eric C; Gist, Nicholas H; Acitelli, Rachelle M; McConnell, Whitni J; Beck, Catherine D; Hausman, Dorothy B; Murrow, Jonathan R; Cureton, Kirk J; Evans, Ellen M
2015-04-01
Individuals diagnosed with the metabolic syndrome (MetS) exhibit elevated postprandial lipemia (PPL). The aims of this investigation were to determine 1) if an acute bout of sprint interval training (SIT) attenuates PPL; and 2) if the attenuation of PPL following 6 wk of SIT is magnified compared with a single session of SIT prior to training in women at-risk for MetS (n = 45; 30-65 yr). Women were randomized to SIT (n = 22) or a nonexercise control (n = 23; CON) for 6 wk. Postprandial responses to a high-fat meal challenge (HFMC) were assessed in the CON group before (B-HFMC) and after (Post-HFMC) without prior exercise and in the SIT group at baseline (B-HFMC) without prior exercise, after an acute bout of SIT (four 30-s all-out sprints with 4-min recovery) prior to (Pre-HFMC), and after the 6-wk intervention (Post-HFMC). Responses to the HFMC were assessed by collecting venous blood samples in the fasted state and at 0, 30, 60, 120, and 180 min postprandial. Compared with baseline, an acute bout of SIT before (Pre-HFMC) and after the 6-wk intervention (Post-HFMC) significantly attenuated fasted TG (P < 0.05; 16.6% and 12.3%, respectively) and postprandial area under the curve (13.1% and 9.7%, respectively; tAUC) TG responses. There was no difference in fasted or tAUC TG responses between Pre-HFMC and Post-HFMC. SIT is an effective mode of exercise to reduce fasted and postprandial TG concentrations in women at-risk for MetS. Six weeks of SIT does not magnify the attenuation of PPL in response to a single session of SIT. Copyright © 2015 the American Physiological Society.
Hafstad, Anne Dragøy; Basnet, Purusotam; Ytrehus, Kirsti; Acharya, Ganesh
2015-01-01
Objective To investigate the effects of high intensity interval training (HIIT) on the maternal heart, fetuses and placentas of pregnant rats. Methods Female Sprague-Dawley rats were randomly assigned to HIIT or sedentary control groups. The HIIT group was trained for 6 weeks with 10 bouts of high intensity uphill running on a treadmill for four minutes (at 85–90% of maximal oxygen consumption) for five days/week. After three weeks of HIIT, rats were mated. After six weeks (gestational day 20 in pregnant rats), echocardiography was performed to evaluate maternal cardiac function. Real-time PCR was performed for the quantification of gene expression, and oxidative stress and total antioxidant capacity was assessed in the tissue samples. Results Maternal heart weight and systolic function were not affected by HIIT or pregnancy. In the maternal heart, expression of 11 of 22 genes related to cardiac remodeling was influenced by pregnancy but none by HIIT. Litter size, fetal weight and placental weight were not affected by HIIT. Total antioxidant capacity, malondialdehyde content, peroxidase and superoxide dismutase activity measured in the placenta, fetal heart and liver were not influenced by HIIT. HIIT reduced the expression of eNOS (p = 0.03), hypoxia-inducible factor 1α (p = 0.04) and glutathione peroxidase 4.2 (p = 0.02) in the fetal liver and increased the expression of vascular endothelial growth factor-β (p = 0.014), superoxide dismutase 1 (p = 0.001) and tissue inhibitor of metallopeptidase 3 (p = 0.049) in the fetal heart. Conclusions Maternal cardiac function and gene expression was not affected by HIIT. Although HIIT did not affect fetal growth, level of oxidative stress and total antioxidant capacity in the fetal tissues, some genes related to oxidative stress were altered in the fetal heart and liver indicating that protective mechanisms may be activated. PMID:26566220
Marcotte, Mireille; Delisle, Johanne; McNeil, Jeremy N
2007-02-01
The mass of the spermatophore transferred by a previously mated Choristoneura rosaceana male increases with time elapsed since the last mating but, even after 4 days, it never reaches the mass of the spermatophore of a virgin male. However, spermatophore mass is clearly not a good indicator of the male reproductive investment as the quantity of sperm in the second ejaculate of a previously mated male is the same as that of his first, if he is allowed a 2 (eupyrene sperm) to 3 day (apyrene sperm) recovery period. The interval between the first two matings had no influence on female fecundity or longevity but significantly affected fertility if the male had only 1 day to recover. The length of the post-copulatory refractory period was also shorter in females mated with previously mated males than in those mated with virgins, regardless of the male's remating interval. Furthermore, a significant variation in the eupyrene sperm content of the spermatophore transferred by virgin males had no influence on the length of the female refractory period. Globally, these results support the hypothesis that a factor, other than sperm numbers in the spermatheca, is responsible for maintaining the inhibition of pheromone production in this species.
Spector, A.C.; Smith, J.C.; Hollander, G.R.
1986-05-01
Radiation-induced taste aversion has been suggested to possibly play a role in the dietary difficulties observed in some radiotherapy patients. In rats, these aversions can still be formed even when the radiation exposure precedes the taste experience by several hours. This study was conducted to examine whether increasing the radiation exposure level could extend the range of the exposure-taste interval that would still support the formation of a taste aversion. Separate groups of rats received either a 100 or 300 R gamma-ray exposure followed 1, 3, 6, or 24 h later by a 10-min saccharin (0.1% w/v) presentation. A control group received a sham exposure followed 1 h later by a 10-min saccharin presentation. Twenty-four hours following the saccharin presentation all rats received a series of twelve 23-h two-bottle preference tests between saccharin and water. The results indicated that the duration of the exposure-taste interval plays an increasingly more important role in determining the initial extent of the aversion as the dose decreases. The course of recovery from taste aversion seems more affected by dose than by the temporal parameters of the conditioning trial.
Postactivation potentiation: effect of various recovery intervals on bench press power performance.
Ferreira, Sandra Lívia de Assis; Panissa, Valéria Leme Gonçalves; Miarka, Bianca; Franchini, Emerson
2012-03-01
Postactivation potentiation (PAP) is a strategy used to improve performance in power activities. The aim of this study was to determine if power during bench press exercise was increased when preceded by 1 repetition maximum (1RM) in the same exercise and to determine which time interval could optimize PAP response. For this, 11 healthy male subjects (age, 25 ± 4 years; height, 178 ± 6 cm; body mass, 74 ± 8 kg; bench press 1RM, 76 ± 19 kg) underwent 6 sessions. Two control sessions were conducted to determine both bench press 1RM and power (6 repetitions at 50% 1RM). The 4 experimental sessions were composed of a 1RM exercise followed by power sets with different recovery intervals (1, 3, 5, and 7 minutes), performed on different days, and determined randomly. Power values were measured via Peak Power equipment (Cefise, Nova Odessa, São Paulo, Brazil). The conditions were compared using an analysis of variance with repeated measures, followed by a Tukey test. The significance level was set at p < 0.05. There was a significant increase in PAP in concentric contractions after 7 minutes of recovery compared with the control and 1-minute recovery conditions (p < 0.05). Our results indicated that 7 minutes of recovery has generated an increase in PAP in bench press and that such a strategy could be applied as an interesting alternative to enhance the performance in tasks aimed at increasing upper-body power performance.
Palmisano, Maria; Wu, Anfan; Assaf, Mahmoud; Liu, Liangang; Park, C. Hyung; Savant, Ishani; Liu, Yong; Zhou, Simon
2016-01-01
Objective: This study was conducted to evaluate the effect of apremilast and its major metabolites on the placebo-corrected change-from-baseline QTc interval of an electrocardiogram (ECG). Materials and methods: Healthy male subjects received each of 4 treatments in a randomized, crossover manner. In the 2 active treatment periods, apremilast 30 mg (therapeutic exposure) or 50 mg (supratherapeutic exposure) was administered twice daily for 9 doses. A placebo control was used to ensure double-blind treatment of apremilast, and an open-label, single dose of moxifloxacin 400 mg was administered as a positive control. ECGs were measured using 24-hour digital Holter monitoring. Results: The two-sided 98% confidence intervals (CIs) for ΔΔQTcI of moxifloxacin completely exceeded 5 ms 2 – 4 hours postdose. For both apremilast dose studies, the least-squares mean ΔΔQTcI was < 1 ms at all time points, and the upper limit of two-sided 90% CIs was < 10 ms. There were no QT/QTc values > 480 ms or a change from baseline > 60 ms. Exploratory evaluation of pharmacokinetic/pharmacodynamic data showed no trend between the changes in QT/QTc interval and the concentration of apremilast or its major metabolites M12 and M14. Conclusions: Apremilast did not prolong the QT interval and appears to be safe and well tolerated up to doses of 50 mg twice daily. PMID:27285466
Kim, Tae-Oh; Lee, Nae-Young; Kim, Hyoungjun; Seo, Eun Hee; Heo, Nae-Yun; Park, Seung Ha; Moon, Young-Soo
2015-01-01
Background/Aims. The preparation-to-colonoscopy (PC) interval is one of several important factors for the bowel preparation. Short message service (SMS) reminder from a cellular phone has been suggested to improve compliance in various medical situations. We evaluated the effectiveness of SMS reminders to assure the PC interval for colonoscopy. Methodology. This prospective randomized study was investigator blinded. In the No-SMS group, patients took the first 2 L polyethylene glycol (PEG) between 6 and 8 PM on the day before colonoscopy and the second 2 L PEG approximately 6 hours before the colonoscopy without SMS. In the SMS group, patients took first 2 L PEG in the same manner as the No-SMS group and the second 2 L PEG after receiving an SMS 6 hours before the colonoscopy. Results. The SMS group had a lower score than the No-SMS group, according to the Ottawa Bowel Preparation Scale (P < 0.001). Multivariate logistic regression analysis showed that compliance with diet instructions (odds ratio (OR) 2.109; 95% confidence interval (CI), 1.11–3.99, P = 0.022) and intervention using SMS ((OR) 2.329; 95% (CI), 1.34–4.02, P = 0.002) were the independent significant factors for satisfactory bowel preparation. Conclusions. An SMS reminder to assure PC interval improved the bowel preparation quality for colonoscopy with bowel preparation. PMID:25792978
Vallet, J L; Miles, J R; Rempel, L A
2013-05-01
We hypothesized that creatine supplementation would reduce birth intervals, stillbirth rate, and preweaning survival in pigs because of its reported improvement of athletic performance in humans. In Exp. 1, gilts (n = 42) and first parity sows (n = 75) were mated at estrus. Beginning on d 110 of gestation, dams received either no treatment or 20 g creatine daily until farrowing. At farrowing in November 2008, pigs were monitored by video camera to determine individual piglet birth intervals. On d 1, piglets were weighed, euthanized, and the cerebellum, brain stem, and spinal cord were collected from the largest and smallest piglets in each litter to measure myelin basic proteins, myelin cholesterol, glucocerebrosides, phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin. Preweaning mortality of the remaining piglets was recorded, including whether a piglet had been overlayed by the dam. A second experiment was performed using gilts (n = 90), farrowing in July 2010, to test differential effects of creatine supplementation during hot, humid weather when dams typically have more difficulty farrowing. Once again, gilts were provided either no supplementation or 20 g creatine daily from d 110 to the day of farrowing. Gilts were video recorded during farrowing, piglets were weighed on d 1, and preweaning mortality (including overlays) was recorded. In Exp. 1, creatine supplementation had no effect on birth intervals or stillbirth rate. Creatine supplementation improved the amount of myelin lipids in brain regions of piglets, particularly the brain stem. Creatine supplementation also reduced overlays of low birth weight piglets from gilts but not second parity sows. Data from Exp. 2 were combined with gilt data from Exp. 1 to examine the effect of creatine, season, and their interaction. There were no effects of treatment or season on birth intervals, stillbirth rates, or overall preweaning mortality. Creatine treatment reduced the incidence of overlays in low
Godfrey, Richard; Theologou, Thomas; Dellegrottaglie, Santo; Binukrishnan, Sukumaran; Wright, Jay; Whyte, Gregory; Ellison, Georgina
2013-01-01
This is the third in a series of case studies on an individual with normal coronaries who sustained an idiopathic acute myocardial infarction . Bilateral pulmonary emboli almost 2 years post-myocardial infarction (MI) revealed coagulopathy as the cause. The original MI resulted in 16% myocardial scar tissue. An increasing number of patients are surviving MI, hence the burden for healthcare often shifts to heart failure. Accumulating evidence suggests high-intensity aerobic interval exercise (AHIT) is efficacious in improving cardiac function in health and disease. However, its impact on MI scar has never been assessed. Accordingly, the 50-year-old subject of this case study undertook 60 weeks of regular AHIT. Successive cardiac MRI results demonstrate, for the first time, a decrease in MI scar with exercise and, alongside mounting evidence of high efficacy and low risk, suggests AHIT may be increasingly important in future prevention and reversing of disease and or amelioration of symptoms. PMID:23413285
Högberg, M; Dahlborn, K; Hydbring-Sandberg, E; Hartmann, E; Andrén, A
2016-05-01
Milk with a high concentration of fat and casein is required for cheese production, and these components have a major impact for both quality and yield of the curd. Recent observations have shown that suckling can elevate milk fat concentration in goats and our aim was therefore to check the hypothesis that animal welfare and cheese-processing properties of goat milk could be optimised by appropriate management of suckled/milked goats. Twelve Swedish dairy goats were kept together with one kid each in 4 different mixed management-systems (milking combined with partial suckling) in a cross-over design. Two milk accumulation intervals were tested; Short = dams and kids were together for 16 h (T16) and Long = ; dams and kids were together for 8 h (T8 h). In addition, two milking regimes were used; Suckled Before Milking = S and Milked Before Suckling = M. Milk accumulation interval referred to how long dams and kids were separated. The milk yield available for processing (milk offtake), was weighed and analysed from each milking occasion and the suckled milk yield was estimated by a weigh-suckle-weigh method (WSW) in combination with observing the suckling behaviour during the free suckling periods. Milking managements, such as 'suckling before milking (S)', increased milk fat concentration compared to milking before suckling (M) and 'Short accumulation treatments (T16)' gave higher milk fat, casein concentration and individual curd yield (%) compared to the 'Long accumulation treatment (T8)'. The total individual curd yield (g) was the same despite treatment, but the animal welfare was most likely higher in T16 where dams and kids spent more time together.
Wadley, Alex J; Chen, Yu-Wen; Lip, Gregory Y H; Fisher, James P; Aldred, Sarah
2016-01-01
The purpose of the present study was to compare acute changes in oxidative stress and inflammation in response to steady state and low volume, high intensity interval exercise (LV-HIIE). Untrained healthy males (n = 10, mean ± s: age 22 ± 3 years; VO2MAX 42.7 ± 5.0 ml · kg(-1) · min(-1)) undertook three exercise bouts: a bout of LV-HIIE (10 × 1 min 90% VO2MAX intervals) and two energy-matched steady-state cycling bouts at a moderate (60% VO2MAX; 27 min, MOD) and high (80% VO2MAX; 20 min, HIGH) intensity on separate days. Markers of oxidative stress, inflammation and physiological stress were assessed before, at the end of exercise and 30 min post-exercise (post+30). At the end of all exercise bouts, significant changes in lipid hydroperoxides (LOOH) and protein carbonyls (PCs) (LOOH (nM): MOD +0.36; HIGH +3.09; LV-HIIE +5.51 and PC (nmol · mg(-1) protein): MOD -0.24; HIGH -0.11; LV-HIIE -0.37) were observed. Total antioxidant capacity (TAC) increased post+30, relative to the end of all exercise bouts (TAC (µM): MOD +189; HIGH +135; LV-HIIE +102). Interleukin (IL)-6 and IL-10 increased post+30 in HIGH and LV-HIIE only (P < 0.05). HIGH caused the greatest lymphocytosis, adrenaline and cardiovascular response (P < 0.05). At a reduced energy cost and physiological stress, LV-HIIE elicited similar cytokine and oxidative stress responses to HIGH.
Di Iorio, Biagio; Torraca, Serena; Piscopo, Carmine; Sirico, Maria L; Di Micco, Lucia; Pota, Andrea; Tartaglia, Domenico; Berardino, Lorella; Morrone, Luigi F; Russo, Domenico
2012-01-01
Serum concentrations of potassium (K) and calcium (Ca) influence ionic currents and play an important role in the duration of ventricular action potential. Further, the influence of alkalosis in reducing ionized calcium has been well known for a long time. The aim of this study was to assess the effects of different dialysate electrolytes and bicarbonate concentrations on changes of QTc interval in patients on chronic hemodialysis. The study hemodialysis sessions were performed in 22 patients, with different electrolyte and bicarbonate concentrations in dialysate. Tested dialysate concentrations were K of 2 and 3 mmol/L; Ca 1.25, 1.5 and 1.75 mmol/L; and bicarbonate 30 and 34 mmol/L. An electrocardiogram (ECG) was recorded 1 hour before, at the end and every hour for 4 hours after each study dialysis session. QTc interval was measured from the beginning of the QRS complex to the end of a T wave on a 12-lead ECG. Blood was collected and K, total Ca, ionic Ca and pH evaluated. At the end of the study hemodialysis session with dialysate containing low K (2 mmol/L), low Ca (1.25 mmol/L) and high bicarbonate concentration (34 mmol), mean QTc interval was significantly prolonged compared with that recorded with dialysate containing high K (3 mmol/L), high Ca (1.75 mmol/L) and bicarbonate (30 mmol) (40 ± 10 milliseconds vs. 2 ± 2 milliseconds; p<0.01). Dialysate with low concentration of low Ca, K and high concentration of bicarbonate was an independent predictor of QTc; the combination of low Ca and K and high bicarbonate strongly increased the risk of prolonged QTc interval. The present pilot study shows that changes in QTc interval during hemodialysis depend on both electrolyte and bicarbonate concentrations in dialysate.
Prado, D M L; Rocco, E A; Silva, A G; Rocco, D F; Pacheco, M T; Silva, P F; Furlan, V
2016-02-01
The oxygen uptake efficiency slope (OUES) is a submaximal index incorporating cardiovascular, peripheral, and pulmonary factors that determine the ventilatory response to exercise. The purpose of this study was to evaluate the effects of continuous exercise training and interval exercise training on the OUES in patients with coronary artery disease. Thirty-five patients (59.3±1.8 years old; 28 men, 7 women) with coronary artery disease were randomly divided into two groups: continuous exercise training (n=18) and interval exercise training (n=17). All patients performed graded exercise tests with respiratory gas analysis before and 3 months after the exercise-training program to determine ventilatory anaerobic threshold (VAT), respiratory compensation point, and peak oxygen consumption (peak VO2). The OUES was assessed based on data from the second minute of exercise until exhaustion by calculating the slope of the linear relation between oxygen uptake and the logarithm of total ventilation. After the interventions, both groups showed increased aerobic fitness (P<0.05). In addition, both the continuous exercise and interval exercise training groups demonstrated an increase in OUES (P<0.05). Significant associations were observed in both groups: 1) continuous exercise training (OUES and peak VO2 r=0.57; OUES and VO2 VAT r=0.57); 2) interval exercise training (OUES and peak VO2 r=0.80; OUES and VO2 VAT r=0.67). Continuous and interval exercise training resulted in a similar increase in OUES among patients with coronary artery disease. These findings suggest that improvements in OUES among CAD patients after aerobic exercise training may be dependent on peripheral and central mechanisms.
Prado, D.M.L.; Rocco, E.A.; Silva, A.G.; Rocco, D.F.; Pacheco, M.T.; Silva, P.F.; Furlan, V.
2016-01-01
The oxygen uptake efficiency slope (OUES) is a submaximal index incorporating cardiovascular, peripheral, and pulmonary factors that determine the ventilatory response to exercise. The purpose of this study was to evaluate the effects of continuous exercise training and interval exercise training on the OUES in patients with coronary artery disease. Thirty-five patients (59.3±1.8 years old; 28 men, 7 women) with coronary artery disease were randomly divided into two groups: continuous exercise training (n=18) and interval exercise training (n=17). All patients performed graded exercise tests with respiratory gas analysis before and 3 months after the exercise-training program to determine ventilatory anaerobic threshold (VAT), respiratory compensation point, and peak oxygen consumption (peak VO2). The OUES was assessed based on data from the second minute of exercise until exhaustion by calculating the slope of the linear relation between oxygen uptake and the logarithm of total ventilation. After the interventions, both groups showed increased aerobic fitness (P<0.05). In addition, both the continuous exercise and interval exercise training groups demonstrated an increase in OUES (P<0.05). Significant associations were observed in both groups: 1) continuous exercise training (OUES and peak VO2 r=0.57; OUES and VO2 VAT r=0.57); 2) interval exercise training (OUES and peak VO2 r=0.80; OUES and VO2 VAT r=0.67). Continuous and interval exercise training resulted in a similar increase in OUES among patients with coronary artery disease. These findings suggest that improvements in OUES among CAD patients after aerobic exercise training may be dependent on peripheral and central mechanisms. PMID:26871969
Gambini, A; Andrés, G; Jarazo, J; Javier, J; Karlanian, F; Florencia, K; De Stéfano, A; Salamone, D F
2014-02-01
The current limitations for obtaining ovaries from slaughterhouses and the low efficiency of in vivo follicular aspiration necessitate a complete understanding of the variables that affect oocyte developmental competence in the equine. For this reason, we assessed the effect on equine oocyte meiotic competence and the subsequent in vitro cloned embryo development of 1) the time interval between ovary collection and the onset of oocyte in vitro maturation (collection-maturation interval time) and 2) the pregnancy status of the donor mares. To define the collection-maturation interval time, collected oocytes were classified according to the slaughtering time and the pregnancy status of the mare. Maturation rate was recorded and some matured oocytes of each group were used to reconstruct zona free cloned embryos. Nuclear maturation rates were lower when the collection-maturation interval time exceeded 10 h as compared to 4 h (32/83 vs. 76/136, respectively; P = 0.0128) and when the donor mare was pregnant as compared to nonpregnant (53/146 vs. 177/329, respectively; P = 0.0004). Low rates of cleaved embryos were observed when the collection-maturation interval time exceeded 10 h as compared to 6 to 10 h (11/27 vs. 33/44, respectively; P = 0.0056), but the pregnancy status of donor mares did not affect cloned equine blastocyst development (3/49 vs. 1/27 for blastocyst rates of nonpregnant and pregnant groups, respectively; P = 1.00). These results indicate that, to apply assisted reproductive technologies in horses, oocytes should be harvested within approximately 10 h after ovary collection. Also, even though ovaries from pregnant mares are a potential source of oocytes, they should be processed at the end of the collection routine due to the lower collection and maturation rate in this group.
Oude Ophuis, Charlotte M C; van Akkooi, Alexander C J; Rutkowski, Piotr; Voit, Christiane A; Stepniak, Joanna; Erler, Nicole S; Eggermont, Alexander M M; Wouters, Michel W J M; Grünhagen, Dirk J; Verhoef, Cornelis Kees
2016-11-01
Sentinel node biopsy (SNB) is essential for adequate melanoma staging. Most melanoma guidelines advocate to perform wide local excision and SNB as soon as possible, causing time pressure. To investigate the role of time interval between melanoma diagnosis and SNB on sentinel node (SN) positivity and survival. This is a retrospective observational study concerning a cohort of melanoma patients from four European Organization for Research and Treatment of Cancer Melanoma Group tertiary referral centres from 1997 to 2013. A total of 4124 melanoma patients underwent SNB. Patients were selected if date of diagnosis and follow-up (FU) information were available, and SNB was performed in <180 d. A total of 3546 patients were included. Multivariable logistic regression and Cox regression analyses were performed to investigate how baseline characteristics and time interval until SNB are related to positivity rate, disease-free survival (DFS) and melanoma-specific survival (MSS). Median time interval was 43 d (interquartile range [IQR] 29-60 d), and 705 (19.9%) of 3546 patients had a positive SN. Sentinel node positivity was equal for early surgery (≤43 d) versus late surgery (>43 d): 19.7% versus 20.1% (p = 0.771). Median FU was 50 months (IQR 24-84 months). Sentinel node metastasis (hazard ratio [HR] 3.17, 95% confidence interval [95% CI] 2.53-3.97), ulceration (HR 1.99, 95% CI 1.58-2.51), Breslow thickness (HR 1.06, 95% CI 1.04-1.08), and male gender (HR 1.58, 95% CI 1.26-1.98) (all p < 0.00001) were independently associated with worse MSS and DFS; time interval was not. No effect of time interval between melanoma diagnosis and SNB on 5-year survival or SN positivity rate was found for a time interval of up to 3 months. This information can be used to counsel patients and remove strict time limits from melanoma guidelines. Copyright © 2016 Elsevier Ltd. All rights reserved.
Towards the estimation of effect measures in studies using respondent-driven sampling.
Rotondi, Michael A
2014-06-01
Respondent-driven sampling (RDS) is an increasingly common sampling technique to recruit hidden populations. Statistical methods for RDS are not straightforward due to the correlation between individual outcomes and subject weighting; thus, analyses are typically limited to estimation of population proportions. This manuscript applies the method of variance estimates recovery (MOVER) to construct confidence intervals for effect measures such as risk difference (difference of proportions) or relative risk in studies using RDS. To illustrate the approach, MOVER is used to construct confidence intervals for differences in the prevalence of demographic characteristics between an RDS study and convenience study of injection drug users. MOVER is then applied to obtain a confidence interval for the relative risk between education levels and HIV seropositivity and current infection with syphilis, respectively. This approach provides a simple method to construct confidence intervals for effect measures in RDS studies. Since it only relies on a proportion and appropriate confidence limits, it can also be applied to previously published manuscripts.
[Sampling plan, weighting process and design effects of the Brazilian Oral Health Survey].
Silva, Nilza Nunes da; Roncalli, Angelo Giuseppe
2013-12-01
To present aspects of the sampling plan of the Brazilian Oral Health Survey (SBBrasil Project). with theoretical and operational issues that should be taken into account in the primary data analyses. The studied population was composed of five demographic groups from urban areas of Brazil in 2010. Two and three stage cluster sampling was used. adopting different primary units. Sample weighting and design effects (deff) were used to evaluate sample consistency. In total. 37,519 individuals were reached. Although the majority of deff estimates were acceptable. some domains showed distortions. The majority (90%) of the samples showed results in concordance with the precision proposed in the sampling plan. The measures to prevent losses and the effects the cluster sampling process in the minimum sample sizes proved to be effective for the deff. which did not exceeded 2. even for results derived from weighting. The samples achieved in the SBBrasil 2010 survey were close to the main proposals for accuracy of the design. Some probabilities proved to be unequal among the primary units of the same domain. Users of this database should bear this in mind, introducing sample weighting in calculations of point estimates, standard errors, confidence intervals and design effects.
Effect of Sampling Array Irregularity and Window Size on the Discrimination of Sampled Gratings
Evans, David W.; Wang, Yizhong; Haggerty, Kevin M.; Thibos, Larry N.
2009-01-01
The effect of sampling irregularity and window size on orientation discrimination was investigated using discretely sampled gratings as stimuli. For regular sampling arrays, visual performance could be accounted for by a theoretical analysis of aliasing produced by undersampling. For irregular arrays produced by adding noise to the location of individual samples, the incidence of perceived orientation reversal declined and the spatial frequency range of flawless performance expanded well beyond the nominal Nyquist frequency. These results provide a psychophysical method to estimate the spatial density and the degree of irregularity in the neural sampling arrays that limit human visual resolution. PMID:19815023
Stockler, R M; Morin, D E; Lantz, R K; Constable, P D
2009-09-01
The objective was to determine the effect of milking frequency and dosing interval on pharmacokinetics of cephapirin after intramammary infusion. Six healthy Holstein cows were administered cephapirin (200 mg) into 1 rear mammary gland after each of 2 milkings. Cows were milked twice daily (2x) and dosed at a 12-h interval or 3 times daily (3x) and dosed at an 8- or 16-h interval. A duplicated Latin square design allowed each cow to receive all 3 frequency-dose treatments, with intervening washout periods. Concentrations of cephapirin (CEPH) and desacetylcephapirin (DAC) in milk from the treated glands were determined at each milking after infusion using liquid chromatography-mass spectrometry. Data were fitted using 1- and 2-compartment pharmacokinetic models, as well as a noncompartmental model. Cephapirin was rapidly metabolized to DAC in the mammary gland, with DAC being the predominant agent in milk until 48 h after infusion. Pharmacokinetics of CEPH and DAC were similar for all treatment groups, with a 1-compartment model providing a better fit than a 2-compartment model in most instances. Milking frequency did not affect the length of time that milk CEPH concentration exceeded MIC(50) or MIC(90) values (the minimum inhibitory antimicrobial concentration needed to inhibit 50 or 90% of microbial activity, respectively) for common mastitis pathogens, except that cows milked 3x and dosed at a 16-h interval maintained inhibitory concentrations approximately 8 h longer than those dosed at an 8-h interval. Time for milk CEPH concentration to reach the FDA tolerance did not differ among treatment groups [mean +/- SD; 68 +/- 20, 66 +/- 22, and 57 +/- 18 h after last treatment for cows treated at 12, 16, and 8 h, respectively]. Mean residence time for CEPH in the mammary gland was linearly and negatively associated with the volume of milk produced. Calculated CEPH concentration in composite milk from all 4 mammary glands was below the FDA tolerance in all cows by 96 h
Do, Changhee; Wasana, Nidarshani; Cho, Kwanghyun; Choi, Yunho; Choi, Taejeong; Park, Byungho; Lee, Donghee
2013-11-01
This study was performed to estimate the effect of age at first calving and first two calving intervals on productive life and life time profit in Korean Holsteins. Reproduction data of Korean Holsteins born from 1998 to 2004 and lactation data from 276,573 cows with birth and last dry date that calved between 2000 and 2010 were used for the analysis. Lifetime profit increased with the days of life span. Regression of Life Span on Lifetime profit indicated that there was an increase of 3,800 Won (approximately $3.45) of lifetime profit per day increase in life span. This is evidence that care of each cow is necessary to improve net return and important for farms maintaining profitable cows. The estimates of heritability of age at first calving, first two calving intervals, days in milk for lifetime, lifespan, milk income and lifetime profit were 0.111, 0.088, 0.142, 0.140, 0.143, 0.123, and 0.102, respectively. The low heritabilities indicated that the productive life and economical traits include reproductive and productive characteristics. Age at first calving and interval between first and second calving had negative genetic correlation with lifetime profit (-0.080 and -0.265, respectively). Reducing age at first calving and first calving interval had a positive effect on lifetime profit. Lifetime profit increased to approximately 2,600,000 (2,363.6) from 800,000 Won ($727.3) when age at first calving decreased to (22.3 month) from (32.8 month). Results suggested that reproductive traits such as age at first calving and calving interval might affect various economical traits and consequently influenced productive life and profitability of cows. In conclusion, regard of the age at first calving must be taken with the optimum age at first calving for maximum lifetime profit being 22.5 to 23.5 months. Moreover, considering the negative genetic correlation of first calving interval with lifetime profit, it should be reduced against the present trend of increase.
Liu, Xiaofeng Steven
2011-05-01
The use of covariates is commonly believed to reduce the unexplained error variance and the standard error for the comparison of treatment means, but the reduction in the standard error is neither guaranteed nor uniform over different sample sizes. The covariate mean differences between the treatment conditions can inflate the standard error of the covariate-adjusted mean difference and can actually produce a larger standard error for the adjusted mean difference than that for the unadjusted mean difference. When the covariate observations are conceived of as randomly varying from one study to another, the covariate mean differences can be related to a Hotelling's T(2) . Using this Hotelling's T(2) statistic, one can always find a minimum sample size to achieve a high probability of reducing the standard error and confidence interval width for the adjusted mean difference.
Landes, Reid D; Lensing, Shelly Y; Kodell, Ralph L; Hauer-Jensen, Martin
2013-12-01
The dose of a substance that causes death in P% of a population is called an LDP, where LD stands for lethal dose. In radiation research, a common LDP of interest is the radiation dose that kills 50% of the population by a specified time, i.e., lethal dose 50 or LD50. When comparing LD50 between two populations, relative potency is the parameter of interest. In radiation research, this is commonly known as the dose reduction factor (DRF). Unfortunately, statistical inference on dose reduction factor is seldom reported. We illustrate how to calculate confidence intervals for dose reduction factor, which may then be used for statistical inference. Further, most dose reduction factor experiments use hundreds, rather than tens of animals. Through better dosing strategies and the use of a recently available sample size formula, we also show how animal numbers may be reduced while maintaining high statistical power. The illustrations center on realistic examples comparing LD50 values between a radiation countermeasure group and a radiation-only control. We also provide easy-to-use spreadsheets for sample size calculations and confidence interval calculations, as well as SAS® and R code for the latter.
Landes, Reid D.; Lensing, Shelly Y.; Kodell, Ralph L.; Hauer-Jensen, Martin
2014-01-01
The dose of a substance that causes death in P% of a population is called an LDP, where LD stands for lethal dose. In radiation research, a common LDP of interest is the radiation dose that kills 50% of the population by a specified time, i.e., lethal dose 50 or LD50. When comparing LD50 between two populations, relative potency is the parameter of interest. In radiation research, this is commonly known as the dose reduction factor (DRF). Unfortunately, statistical inference on dose reduction factor is seldom reported. We illustrate how to calculate confidence intervals for dose reduction factor, which may then be used for statistical inference. Further, most dose reduction factor experiments use hundreds, rather than tens of animals. Through better dosing strategies and the use of a recently available sample size formula, we also show how animal numbers may be reduced while maintaining high statistical power. The illustrations center on realistic examples comparing LD50 values between a radiation countermeasure group and a radiation-only control. We also provide easy-to-use spreadsheets for sample size calculations and confidence interval calculations, as well as SAS® and R code for the latter. PMID:24164553
Pereira, Diana R; Costa, Patrício; Cerqueira, João J
2015-08-01
The Symbol Digit Modalities Test (SDMT) is a widely used instrument to assess information processing speed, attention, visual scanning, and tracking. Considering that repeated evaluations are a common need in neuropsychological assessment routines, we explored test-retest reliability and practice effects of two alternate SDMT forms with a short inter-assessment interval. A total of 123 university students completed the written SDMT version in two different time points separated by a 150-min interval. Half of the participants accomplished the same form in both occasions, while the other half filled different forms. Overall, reasonable test-retest reliabilities were found (r = .70), and the subjects that completed the same form revealed significant practice effects (p < .001, dz = 1.61), which were almost non-existent in those filling different forms. These forms were found to be moderately reliable and to elicit a similar performance across participants, suggesting their utility in repeated cognitive assessments when brief inter-assessment intervals are required. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Iida, Naritoshi; Kimura, Hiroshi
2007-12-01
The effects of reinforcement and punishment on response suppression under variable-ratio reinforcement and variable-interval punishment schedules were investigated. In the baseline period, lever pressing in rats was maintained by a variable-ratio food reinforcement schedule. In the punishment condition, responding was punished by a grid shock under a variable-interval schedule. Baseline and punishment conditions alternated, and were continued until the response stabilized. Three rats were given five or six punishment rates with a fixed reinforcement rate and another three rats were given four or five reinforcement rates with a fixed punishment rate. The results indicated that the responses were either completely suppressed or not suppressed at all. When the punishment rate increased or the reinforcement rate decreased, the response was suppressed completely. Whereas when the punishment rate decreased or the reinforcement rate increased, the responses were not suppressed. These results agree with the predictions of the molar theory.
Temperature effects: methane generation from landfill samples
Hartz, K.E.; Klink, R.E.; Ham, R.K.
1983-08-01
An understanding of the breakdown of municipal solid wastes into gaseous products, especially methane, is important. Landfills act as batch anaerobic digestors. Temperature, one of the variables that affect digestion is examined. Since very minor temperature changes can be accomplished with rather substantial changes in methane generation, the generation rate can be modified to match the capacity of the gas recovery system. The effects of moisture content, oxygen supply, liquid solid ratios and bacterial acclimation are mentioned.
Silva, Rehan; Walter, Gimme H; Wilson, Lewis J; Furlong, Michael J
2016-12-01
We investigated the responses of 3 thrips species, Frankliniella schultzei Trybom, F. occidentalis Pergrande, and Thrips tabaci Lindeman (Thysanoptera: Thripidae) to herbivore-damaged and undamaged cotton seedlings (Gossypium hirsutum L. [Malvales: Malvaceae]) at a range of time intervals following damage by adult Tetranychus urticae (Koch), adult T. ludeni (Zacher) (Acari: Tetranychidae) or Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae in olfactometer assays. The intensity/frequency of the response of thrips to herbivore-induced plants decreased with time and ultimately disappeared in all cases; however, the rate at which the response declined was related to the herbivore species that inflicted the damage. All 3 species of thrips were attracted to plants damaged by T. urticae for longer than they were to plants damaged by T. ludeni. The duration for which damaged plants remained attractive was also affected by the degree of damage inflicted on cotton seedlings. For example, F. schultzei was attracted to plants damaged by a higher density of two-spotted spider mites (100/plant) for much longer than to plants damaged by a lower density of these mites (50/plant). The results reinforce previous studies that demonstrate that arrangement of variables influences the responses of thrips to their herbivore-induced cotton host plants. Results also show that these responses are variable in time following herbivore damage to cotton plants, which further demonstrates how difficult it is to generalize about the functional significance of these interactions. © 2015 Institute of Zoology, Chinese Academy of Sciences.
Pain and thermal sensation in the cold: the effect of interval versus continuous exercise.
Muller, Matthew D; Muller, Sarah M; Ryan, Edward J; Bellar, David M; Kim, Chul-Ho; Glickman, Ellen L
2011-06-01
Military and factory work often involves exposure to cold temperatures. With prolonged exposure, individuals report feeling cold and develop pain in their hands, both of which might be alleviated by endogenous heat production via exercise. The purpose of this study was to evaluate how interval (INT) and continuous (CONT) cycle ergometry alter thermal sensation, hand pain, mean finger temperature, and skin surface temperature gradient (forearm-finger) following immobility in moderate cold. Fourteen young men underwent two trials (each was three total hours in 5°C) consisting of a 90-min period of acute cold exposure (ACE), 30 min of exercise (INT or CONT), and a 60-min recovery period (REC). INT and CONT were isoenergetic, reflecting 50 ± 1% of each individual's VO(2) peak. All perceptual scales were significantly correlated during ACE (i.e., test-retest reliability). As expected, individuals felt colder and reported more hand pain during ACE, as compared to thermoneutral conditions. Relative to ACE, both INT and CONT increased mean finger temperature, which was associated with warmer thermal sensation and less hand pain. During REC in 5°C, individuals felt colder and reported more hand pain than during exercise. Although there were no perceptual differences between INT and CONT, moderate exercise in general can cause subjective feelings of warmth and less hand pain in people acutely exposed to moderate cold.
Dispersion-enhanced phase noise effects on reduced-guard-interval CO-OFDM transmission.
Zhuge, Qunbi; Chen, Chen; Plant, David V
2011-02-28
Unlike conventional CO-OFDM systems, we show in this paper that reduced-guard-interval (RGI) CO-OFDM systems experience subcarrier-dependent phase noise (PN) from the local oscillator laser. This phenomenon manifests in RGI-CO-COFM systems because the chromatic dispersion (CD) induced walk-off becomes comparable to the OFDM symbol length. We term this phenomenon the dispersion enhanced PN (DEPN). In this work an analytical study of the impact of DEPN on CO-OFDM transmission is conducted. We develop a system-level analytical model and calculate the variance of the dispersion-induced subcarrier-dependent phase rotation term (PRT) using two different distribution patterns of pilot subcarriers (PS). Moreover, we present a bit error rate (BER) estimator to quantify the system performance degradation due to PRT. Numerical simulations are then performed to verify the analytical model. Finally, we propose a grouped maximum-likelihood (GML) phase estimation approach to mitigate the DEPN impairment, and demonstrate a 0.7-1.7 dB SNR improvement at BER=10⁻³ for typical 100 Gb/s RGI CO-OFDM systems.
Effect of intermittent positive pressure ventilation on cardiac systolic time intervals.
Brundin, T; Hedenstierna, G; McCarthy, G
1976-01-01
The measurement of systolic time intervals (STI) has been widely used as a non-invasive method of assessing the inotropic state of the heart, and normal values are available for healthy individuals breathing spontaneously. The present study was performed in order to evaluate how intermittent positive pressure ventilation (IPPV) affects STI. Ten subjects were investigated before and during halothane anaesthesia for routine surgery. Oesophageal pressure, respiratory minute volume and frequency, arterial blood-gas tensions, cardiac output and heart rate were also measured simultaneously. As expected, the institution of IPPV was associated with a reduction in cardiac output and an increase in oesophageal pressure. Paco2 was reduced. These changes were associated with a considerable lengthening of electro-mechanical systole. This was due to a lengthened pre-ejection period (PEP), whereas the left ventricular ejection time (LVET) was slightly shortened. These changes were even more marked during artifical hyperventilation. The changes in STI are attributed mainly to the reduction of venous return to the heart, subsidiary factors being intrathoracic pressure, myocardial inotropy and vascular resistance.
Effects of input methods on inter-key press intervals during continuous typing.
Liang, Huey-Wen; Hwang, Yaw-Huei; Chang, Fu-Han
2009-09-01
Two popular input methods for Chinese typing, Microsoft New Phonetic and Boshiamy, were compared in terms of hand and finger loading, key-pressing speed and typing efficiency. Sixteen subjects typed an English and a Chinese text for 30 min each during two test sessions and all keystrokes and their inter-key press intervals were recorded by electronic activity monitoring software. Typing with Microsoft New Phonetic and with Boshiamy was found to have equal hand loadings, but typing with Microsoft New Phonetic was associated with a higher proportion of keystrokes at the number row. The subjects who used Boshiamy typed significantly more words per min than those who used Microsoft New Phonetic, though both groups had similar English typing speeds. The features of requiring fewer keystrokes to build a character and no need to choose matched words among homophones made Boshiamy a more efficient tool, but the risk of musculoskeletal disorders should be studied further. This study examined two input methods for typing Chinese and showed that typing with Boshiamy had a higher efficiency, including a higher proportion of key presses on the home row, required fewer key presses to build characters and resulted in a faster speed than with Microsoft New Phonetic. However, the potential risk of development of upper limb symptoms warrants further study.
Effects of retention intervals on receiver operating characteristics in artificial grammar learning.
Tunney, Richard J; Bezzina, Gilbert
2007-05-01
Current theories of memory suggest that recognition is composed of separate processes of familiarity and recollection (e.g. [Yonelinas, A. P. (2002). The nature of recollection and familiarity: a review of 30 years of research. Journal of Memory and Language, 46, 441-517]). A key feature of these two processes is that they decay, or are forgotten at different rates. The dual-process model has also been useful in understanding artificial grammar learning. We obtained evidence for recollection and familiarity in artificial grammar learning by analyses of receiver operating characteristics (ROC). Furthermore we found that these were dissociated by retention intervals of 14 days. The slope of the zROC curves deviated reliably from 1 immediately after study and increased towards 1 suggesting that recollection contributed to recognition decisions but declined over the 14-day period leaving familiarity as the only basis for recognition. These data show similar patterns to those observed in word-recognition [Gardiner, J. M., & Java, R. I. (1991). Forgetting in recognition memory with and without recollective experience. Memory &Cognition, 19, 617-623; Tunney, R. J. (submitted for publication). Changes in the subjective experience of recognition over time suggest independent processes] and confirm the view that recollection and familiarity are implicated in artificial grammar learning. Moreover, the data confirm the finding that recollection and familiarity-based memory show different patterns of forgetting.
Arnaiz, Pilar; Dumas, Eduardo; Heusser, Felipe; González, Rolando; Jalil, Jorge
2004-02-01
In normal children, any procedure that increases heart rate, such as the tilt test, may shorten the QT interval. The effect of the tilt test on QT interval in children with syncope remains unknown. We analyzed the response of RR and QT intervals during a tilt test in 3 groups of children: 28 healthy children (group 1), 26 with syncope of unknown etiology and negative tilt test results (group 2), and 17 with vasovagal syncope (group 3). During the tilt test, RR and QT intervals were significantly shortened in groups 1 and 2. In group 3, RR interval was lengthened during syncope whereas the QT interval remained constant. QT interval lengthening during the tilt test is not a characteristic finding in normal children or in children with vasovagal syncope.
Morphology changes for copper surfaces exposed to different water parameters were investigated at the nanoscale with atomic force microscopy (AFM), as influenced by changes in pH and the levels of orthophosphate ions. Synthetic water samples were designed to mimic physiological c...
Morphology changes for copper surfaces exposed to different water parameters were investigated at the nanoscale with atomic force microscopy (AFM), as influenced by changes in pH and the levels of orthophosphate ions. Synthetic water samples were designed to mimic physiological c...
FELLMAN, C. L.; ARCHER, T. M.; STOKES, J. V.; WILLS, R. W.; LUNSFORD, K. V.; MACKIN, A. J.
2016-01-01
The duration of immunosuppressive effects following oral cyclosporine in dogs is unknown. This study used flow cytometry and quantitative reverse transcription–polymerase chain reaction (qRT-PCR) to evaluate the effects of high-dose oral cyclosporine across a 12-h dosing interval. Expression of interleukin-2 (IL-2) and interferon-gamma (IFN-γ) was compared before and after 8 days of cyclosporine at 10 mg/kg every 12 h in six healthy dogs. Samples were collected at 0, 2, 4, and 8 h postdosing for analysis of unactivated and activated T-cell and whole blood cytokine expression using flow cytometry and qRT-PCR, respectively, and at 0, 2, 4, 6, 8, and 10 h postdosing for measurement of cyclosporine concentrations. Flow cytometry and qRT-PCR both demonstrated significant marked reductions in IL-2 and IFN-γ levels at 0, 2, 4, and 8 h after dosing compared to pretreatment levels (P < 0.05) for activated samples, with less consistent effects observed for unactivated samples. Both flow cytometry and qRT-PCR are viable techniques for measuring cyclosporine pharmacodynamics in dogs, yielding comparable results with activated samples. Two hours postdrug administration is the preferred time for concurrent assessment of peak drug concentration and cytokine expression, and T-cell activation is needed for optimal results. PMID:26676223
Abbey, Antonia; Wegner, Rhiana; Pierce, Jennifer; Jacques-Tiura, Angela J.
2012-01-01
Objective The goal of this study is to distinguish risk factors associated with young men's self-reports of continuing (persistence), stopping (desistance), and starting (initiation) sexual aggression against women over a one year time period. This study fills gaps in the literature not addressed in other studies by examining a wide range of predictor variables prospectively in a community sample. Method Single men age 18 to 35 were recruited through telephone sampling in a large metropolitan region. In person audio computer-assisted self interviews were completed at baseline and one year later (n = 423). Results By the follow-up interview, half of the participants reported engaging in some type of sexual activity with a woman when they knew she was unwilling. Discriminant function and analysis of variance demonstrated that persistent sexual aggressors had the most extreme scores on many baseline and follow-up measures including childhood victimization, social deviance, personality traits, frequency of misperception of women's sexual intent, and expectancies about alcohol's effects. At follow-up, desisters had fewer sexual partners than did persisters. Also at follow-up, initiators misperceived more women's sexual intentions, had stronger alcohol expectancies, drank more alcohol in sexual situations, and were with women who drank more alcohol as compared to nonperpetrators. Conclusions Given the extremely high rates of self-reported sexual aggression, universal prevention programs are needed. Targeted interventions should focus on youth who were victimized in childhood, engage in delinquent behavior, are narcissistic and unconcerned about others, enjoy impersonal sex, drink heavily, and believe that alcohol enhances sexuality. PMID:22272382
Axelrod, M
2005-08-18
Discovery sampling is a tool used in a discovery auditing. The purpose of such an audit is to provide evidence that some (usually large) inventory of items complies with a defined set of criteria by inspecting (or measuring) a representative sample drawn from the inventory. If any of the items in the sample fail compliance (defective items), then the audit has discovered an impropriety, which often triggers some action. However finding defective items in a sample is an unusual event--auditors expect the inventory to be in compliance because they come to the audit with an ''innocent until proven guilty attitude''. As part of their work product, the auditors must provide a confidence statement about compliance level of the inventory. Clearly the more items they inspect, the greater their confidence, but more inspection means more cost. Audit costs can be purely economic, but in some cases, the cost is political because more inspection means more intrusion, which communicates an attitude of distrust. Thus, auditors have every incentive to minimize the number of items in the sample. Indeed, in some cases the sample size can be specifically limited by a prior agreement or an ongoing policy. Statements of confidence about the results of a discovery sample generally use the method of confidence intervals. After finding no defectives in the sample, the auditors provide a range of values that bracket the number of defective items that could credibly be in the inventory. They also state a level of confidence for the interval, usually 90% or 95%. For example, the auditors might say: ''We believe that this inventory of 1,000 items contains no more than 10 defectives with a confidence of 95%''. Frequently clients ask their auditors questions such as: How many items do you need to measure to be 95% confident that there are no more than 10 defectives in the entire inventory? Sometimes when the auditors answer with big numbers like ''300'', their clients balk. They balk because a
Thrailkill, Eric A; Epstein, Leonard H; Bouton, Mark E
2015-01-01
Food variety increases consumption and the rate of instrumental behavior that is reinforced by food in humans and animals. The present experiment investigated the relationship between the variety effect and habituation to food by testing the role of the interval between successive food presentations on responding in an operant food-seeking task. Habituation to food was expected at short, but not long, interfood intervals. The effects of variety on food's long-term reinforcing value were also tested. Four groups of rats were trained to lever-press on different random-interval (RI) schedules of reinforcement to earn 45-mg food pellets. Half the rats in each group received an unpredictable mix of grain and sucrose pellets, while the other half consistently received sucrose pellets. Response rate began at a high rate and then decreased within each 30-min session for groups that received short inter-pellet intervals (i.e., RI-3 s and RI-6 s reinforcement schedules) but not in groups that received longer inter-pellet intervals (i.e., RI-12 s and RI-24 s). A variety effect in the form of higher responding in the mix group than the sucrose-only group was also only evident at the shorter intervals. Habituation and variety effects were also most evident with the short intervals when we controlled for the number of reinforcers earned, suggesting that they were not merely due to rapid satiation. The variety effect also appeared quickly when groups trained with longer inter-pellet intervals (RI-12 s and RI-24 s) were transitioned to shorter intervals (RI-3 s and RI-6 s). There was no effect of variety on resistance to extinction or on resistance to the response-suppressing effects of pre-session feeding. The results more clearly link this version of the variety effect to the short-term effect of variety on food habituation.
Bonato, Matteo; La Torre, Antonio; Saresella, Marina; Marventano, Ivana; Merati, Giampiero; Vitale, Jacopo Antonino
2017-04-14
Due to personal and working necessities, the time for exercise is often short, and scheduled early in the morning or late in the afternoon. Cortisol plays a central role in the physiological and behavioral response to a physical challenge and can be considered as an index of exercise stress. Therefore, the aim of this study was to evaluate the influence of the circadian phenotype classification on salivary cortisol concentration in relation to an acute session of high-intensity interval exercise (HIIE) performed at different times of the day. Based on the morningness-eveningness questionnaire, 12 M-types (N = 12; age 21 ± 2 years; height 179 ± 5 cm; body mass 74 ± 12 kg, weekly training volume 8 ± 1 hours) and 11 E-types (N = 11; age 21 ± 2 years; height 181 ± 11 cm; body mass 76 ± 11 kg, weekly training volume 7 ± 2 hours) were enrolled in a randomized crossover study. All subjects underwent measurements of salivary cortisol secretion before (PRE), immediately after (POST), and 15 min (+15 min), 30 min (+30 min), 45 min (+45 min) and 60 min (+60 min) after the completion of both morning (08.00 am) and evening (08.00 p.m.) high-intensity interval exercise. Two-way analysis of variance with Tuckey's multiple comparisons test showed significant increments over PRE-cortisol concentrations in POSTcondition both in the morning (4.88 ± 1.19 ng · mL(-1) vs 6.60 ± 1.86 ng · mL(-1), +26.1%, P < 0.0001, d > 0.8) and in the evening (1.56 ± 0.48 ng · mL(-1) vs 2.34 ± 0.37, +33.4%, P = 0.034, d > 0.6) exercise in all the 23 subject that performed the morning and the evening HIIE. In addition, during morning exercise, significant differences in cortisol concentration between M-types and E-types at POST (5.49 ± 0.98 ng · mL(-1) versus 8.44 ± 1.08 ng · mL(-1), +35%, P < 0.0001, d > 0.8), +15 min (4.52 ± 0.42 ng · mL(-1) versus 6.61 ± 0.62 ng · mL(-1), +31.6%, P < 0.0001, d > 0.8), +30 min (4.10 ± 1.44 ng · mL(-1) versus 6.21 ± 1.60 ng · mL(-1), +34.0%, P
The Effects of Rest Interval on Quadriceps Torque During an Isokinetic Testing Protocol in Elderly
Bottaro, Martim; Russo, André Faria; de Oliveira, Ricardo Jacó
2005-01-01
The purpose of this study was to compare three different intervals for a between sets rest period during a common isokinetic knee extension strength-testing protocol of twenty older Brazilian men (66.30 ± 3.92 yrs). The volunteers underwent unilateral knee extension (Biodex System 3) testing to determine their individual isokinetic peak torque at 60, 90, and 120°s-1. The contraction speeds and the rest periods between sets (30, 60 and 90 s) were randomly performed in three different days with a minimum rest period of 48 hours. Significant differences between and within sets were analyzed using a One Way Analysis of Variance (ANOVA) with repeated measures. Although, at angular velocity of 60°s-1 produced a higher peak torque, there were no significant differences in peak torque among any of the rest periods. Likewise, there were no significant differences between mean peak torque among all resting periods (30, 60 and 90s) at angular velocities of 90 and 120°s-1. The results showed that during a common isokinetic strength testing protocol a between set rest period of at least 30 s is sufficient for recovery before the next test set in older men. Key Points The assessment of muscular strength using isokinetics muscle contraction in older individuals is very important for exercise prescription and rehabilitation. The minimal time between intraset isokinetics knee extension assessment in older individuals need to be more investigated, however 30 s appear to besufficient time for strength recover. PMID:24453533
González-Mohíno, Fernando; González-Ravé, José M; Juárez, Daniel; Fernández, Francisco A; Barragán Castellanos, Rubén; Newton, Robert U
2016-04-01
The purpose of this study was to evaluate the effects on running economy (RE), V[Combining Dot Above]O2max, maximal aerobic speed (MAS), and gait kinematics (step length [SL] and frequency, flight and contact time [CT]) in recreational athletes, with 2 different training methods, Interval and Continuous (CON). Eleven participants were randomly distributed in an interval training group (INT; n = 6) or CON training group (CON; n = 5). Interval training and CON performed 2 different training programs (95-110% and 70-75% of MAS, respectively), which consisted of 3 sessions per week during 6 weeks with the same external workload (%MAS × duration). An incremental test to exhaustion was performed to obtain V[Combining Dot Above]O2max, MAS, RE, and gait variables (high speed camera) before and after the training intervention. There was a significant improvement (p ≤ 0.05) in RE at 60 and 90% of MAS by the CON group; without changes in gait. The INT group significantly increased MAS and higher stride length at 80, 90, and 100% of MAS and lower CT at 100% of MAS. As expected, training adaptations are highly specific to the overload applied with CON producing improvements in RE at lower percentage of MAS whereas INT produces improvements in MAS. The significantly increased stride length and decreased CT for the INT group are an important outcome of favorable changes in running gait.
Effect of sampling frequency on estimates of cumulative nitrous oxide emissions.
Parkin, Timothy B
2008-01-01
It is generally recognized that soil N(2)O emissions can exhibit pronounced day-to-day variations; however, measurements of soil N(2)O flux with soil chambers typically are done only at discrete points in time. This study evaluated the impact of sampling frequency on the precision of cumulative N(2)O flux estimates calculated from field measurements. Automated chambers were deployed in a corn/soybean field and used to measure soil N(2)O fluxes every 6 h from 25 Feb. 2006 through 11 Oct. 2006. The chambers were located in two positions relative to the fertilizer bands-directly over a band or between fertilizer bands. Sampling frequency effects on cumulative N(2)O-N flux estimation were assessed using a jackknife technique where populations of N(2)O fluxes were constructed from the average daily fluxes measured in each chamber. These test populations were generated by selecting measured flux values at regular time intervals ranging from 1 to 21 d. It was observed that as sampling interval increased from 7 to 21 d, variances associated with cumulative flux estimates increased. At relatively frequent sampling intensities (i.e., once every 3 d) N(2)O-N flux estimates were within +/-10% of the expected value at both sampling positions. As the time interval between sampling was increased, the deviation in estimated cumulative N(2)O flux increased, such that sampling once every 21 d yielded estimates within +60% and -40% of the actual cumulative N(2)O flux. The variance of potential fluxes associated with the between-band positions was less than the over-band position, indicating that the underlying temporal variability impacts the efficacy of a given sampling protocol.
Gahreman, Daniel E; Boutcher, Yati N; Bustamante, Sonia; Boutcher, Stephen H
2016-03-31
This study investigated the combined effect of green tea and acute interval sprinting exercise on fat oxidation of trained and untrained males. Fourteen trained and 14 untrained males ingested one capsule containing either green tea or cellulose with breakfast, lunch, and dinner, 24 hours before two exercise sessions. A fourth capsule was consumed 90 minutes before exercise after overnight NPO (nil per os). Participants performed a 20-minute interval sprinting cycling protocol, consisting of repeated bouts of 8-seconds of sprint cycling (at 65% of maximum power output) and 12-seconds of recovery (at 25% of maximum power output), followed by 75 minutes of post-exercise recovery. Fat oxidation was significantly greater in the resting condition after green tea ingestion (p < 0.05) compared with the placebo. Fat oxidation was also significantly increased post-exercise in the green tea, compared with the placebo condition (p < 0.01). During and after exercise the plasma glycerol levels significantly increased in both groups after green tea consumption and were significantly higher in the untrained group compared with the trained group (p < 0.05). Compared with the placebo, the plasma epinephrine levels were significantly higher for both groups in the green tea condition during and after exercise, however, norepinephrine levels were only significantly greater, p < 0.05, during and after exercise in the untrained group. Green tea significantly increased resting and post-exercise fat oxidation and also elevated plasma glycerol and epinephrine levels during and after interval sprinting. Glycerol and norepinephrine levels during interval sprinting were significantly higher in the untrained group compared with the trained group.
Gahreman, Daniel E; Boutcher, Yati N; Bustamante, Sonia; Boutcher, Stephen H
2016-01-01
[Purpose] This study investigated the combined effect of green tea and acute interval sprinting exercise on fat oxidation of trained and untrained males. [Methods] Fourteen trained and 14 untrained males ingested one capsule containing either green tea or cellulose with breakfast, lunch, and dinner, 24 hours before two exercise sessions. A fourth capsule was consumed 90 minutes before exercise after overnight NPO (nil per os). Participants performed a 20-minute interval sprinting cycling protocol, consisting of repeated bouts of 8-seconds of sprint cycling (at 65% of maximum power output) and 12-seconds of recovery (at 25% of maximum power output), followed by 75 minutes of post-exercise recovery. [Results] Fat oxidation was significantly greater in the resting condition after green tea ingestion (p < 0.05) compared with the placebo. Fat oxidation was also significantly increased post-exercise in the green tea, compared with the placebo condition (p < 0.01). During and after exercise the plasma glycerol levels significantly increased in both groups after green tea consumption and were significantly higher in the untrained group compared with the trained group (p < 0.05). Compared with the placebo, the plasma epinephrine levels were significantly higher for both groups in the green tea condition during and after exercise, however, norepinephrine levels were only significantly greater, p < 0.05, during and after exercise in the untrained group. [Conclusion] Green tea significantly increased resting and post-exercise fat oxidation and also elevated plasma glycerol and epinephrine levels during and after interval sprinting. Glycerol and norepinephrine levels during interval sprinting were significantly higher in the untrained group compared with the trained group. PMID:27298806
Kolben, Theresa M; Bergauer, Florian; Moeckel, Jochen; Boettcher, Berit; Thaler, Christian J; Kolben, Thomas; Crispin, Alexander; Dannecker, Christian; Mahner, Sven; Gallwas, Julia
2017-06-01
A repeat Pap smear is sometimes necessary after a short time interval or even immediately, when patients seek for a second opinion or due to study participation. Only limited information is available on the possible impact of a short interval between two Pap smears. Most institutions therefore practice a minimum time span of 6-8 weeks before obtaining a second smear since a short interval is commonly believed to be associated with an increase of false negative results in the second smear. Two consecutive Pap smears were obtained from 81 women. 41 smears were processed using the conventional technique, whereas liquid-based cytology was used in the remaining 40 women. Smears were independently evaluated by four different cytopathologists. We analyzed the effect of time interval, both processing techniques and inter-observer variance in cytological evaluation. While the result of the second smear shows a tendency towards a more benign outcome (odds ratio (OR) 1.436, 95% CI 0.972-2.121), this difference was not statistically significant (p = 0.07). No significant differences were observed between conservative and liquid-based cytology (OR 1.554, 95% CI 0.659-3.667, p = 0.31). There was considerable inter-observer variability, and the observer was a strong predictor of the cytological result (OR 0.632-5.083, 95% CI 0.355-8.975, p < 0.01). We document a tendency towards a more benign outcome without statistical significance in the second smear. Inter-observer variability of different cytopathologists is high and should be kept in mind when evaluating cytology results.
Filho, José C Jambassi; Gobbi, Lilian T B; Gurjão, André L D; Gonçalves, Raquel; Prado, Alexandre K G; Gobbi, Sebastião
2013-01-01
The purpose of this study was to assess the effect of different rest intervals (RI) between sets on number of repetitions, sustainability of repetitions, and total volume during a leg press exercise. Seventeen resistance-trained older women (68.0 ± 5.9 years, 71. 2 ± 11.7 kg, 1.58 ± 0.07 m) participated in the study. All participants performed three sets to voluntary exhaustion, with loads that corresponded to 15 maximum repetitions, in two experimental sessions (that ranged from 48 to 72 hours apart). In each session, one of two RI (one-minute: RI-1 and three minute: RI-3) was tested, employing a randomized and counterbalanced design. For both RI, significant reductions (p < 0.05) were observed in the number of repetitions and sustainability of repetitions, from the first to the second and third sets. Differences (p < 0.05) between the RI also were observed in the two final sets. The total volume for the RI-3 session was statistically higher (29.4%, p < 0.05) as compared to the RI-1 session. The length of the RI between sets influenced the number of repetitions, sustainability of repetitions, and total volume. The longer RI should be used, therefore, when the goal of training is to increase the total volume. Key pointsThis study examined the influence of rest intervals, between sets, on muscle performance during leg press exercise, in trained older women.When multiple sets were performed to voluntary exhaustion, neither short and long rest interval (1 and 3 minutes, respectively) promoted the sustainability of repetitions in subsequent sets.A longer rest interval seems to be necessary for a higher number of repetitions in subsequent sets, and with increase in time of tension and total volume.
Shin, Janey; Darlington, Gerarda A; Cotton, Cecilia; Corey, Mary; Bull, Shelley B
2007-07-01
Complex diseases are influenced by both genetic and environmental factors. Studies of individuals or of families can be used to examine the association of genetic factors, such as candidate genes, and other risk factors with the presence or absence of complex disorders. If families are investigated, whether or not they are randomly ascertained, possible familial correlation among observations must be considered. We have compared two statistical approaches for analyzing correlated binary data from randomly ascertained nuclear families. The generalized estimating equations approach (GEE) can be used to adjust for familial correlation. The relationship between covariates and the response is modelled, and the correlations among family members are treated as nuisance parameters. For comparison, we have proposed two strategies from a hierarchical nonparametric bootstrap approach. One strategy (S1) samples family units, preserving the structure and correlation within each family. A second and novel strategy (S2) also samples family units but then randomly samples offspring with replacement in each family. We applied the methods to data from a study of cardiovascular disease, and followed up with a simulation study in which family data were generated from an underlying multifactorial genetic model. Although the bootstrap approach was more computationally demanding, it outperformed the GEE in terms of confidence interval coverage probabilities for all sample sizes considered.
Lee, Chia-Lun; Hsu, Mei-Chich; Astorino, Todd A; Liu, Ta-Wei; Chang, Wen-Dien
2017-04-01
Weekly training volumes for triathlete are typically higher and may cause fatigue and musculoskeletal injury risk. High-intensity interval training (HIT) is a potent time-efficient strategy to induce adaptations normally associated with traditional endurance training. Therefore, the aim of this study was to investigate the effect of two weeks of in-season HIT on exercise capacity and hormonal responses in young triathletes. Twelve adolescent triathletes performed 18 sessions of HIT over 2 weeks including swim, cycle, and run events. The 6-day training blocks were separated by 1 day of recovery. Pre- and post-training, peak oxygen uptake (VO2peak) and exercise performance were assessed, and blood samples were obtained to detect changes in hormone and metabolite levels. VO2peak was significantly higher (P=0.02) post-training (56.4±8.1 mL·min-1·kg-1) versus pre-training (55.1±7.5 mL·min-1·kg-1). Mean power and total work during 6×10 s repeated-sprint tests significantly increased (P=0.03) after HIT. Additionally, 750 m swim time (pre- vs. post: 689.7±102.5 s vs. 662.0±75 s, P=0.01) and 20 km cycling time (pre- vs. post: 1856.6±274.8 s vs. 1705.4±266.8 s, P=0.02) were significantly lower post-training compared to pre-training, but there was no significant difference in 5 km run time after HIT (pre- vs. post: 1315.8±81.3 s vs. 1292.0±112.9 s, P=0.31). In contrast to pre-training, ammonia concentration was significantly increased (P<0.01) and creatine kinase concentration was significantly decreased (P=0.02) post-training. These findings suggest that two weeks of HIT using HRpeak as a monitor of physiological intensity improved VO2peak, sprint performance, and triathlon-specific performance in adolescent triathletes and attenuated levels of muscle damage.
Image sampling, reconstruction, and the effect of sample-scene phasing
NASA Technical Reports Server (NTRS)
Park, S. K.; Schowengerdt, R. A.
1982-01-01
This paper is a 1-D analysis of the degradation caused by image sampling and interpolative reconstruction. The analysis includes the sample-scene phase as an explicit random parameter and provides a complete characterization of this image degradation as the sum of two terms: one term accounts for the mean effect of undersampling (aliasing) and nonideal reconstruction averaged over all sample-scene phases; the other term accounts for variations about this mean. The results of this paper have application to the design and performance analysis of image scanning, sampling, and reconstruction systems.
Dedoncker, Josefien; Brunoni, Andre R; Baeken, Chris; Vanderhasselt, Marie-Anne
2016-10-01
Recently, there has been wide interest in the effects of transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC) on cognitive functioning. However, many methodological questions remain unanswered. One of them is whether the time interval between active and sham-controlled stimulation sessions, i.e. the interval between sessions (IBS), influences DLPFC tDCS effects on cognitive functioning. Therefore, a systematic review and meta-analysis was performed of experimental studies published in PubMed, Science Direct, and other databases from the first data available to February 2016. Single session sham-controlled within-subject studies reporting the effects of tDCS of the DLPFC on cognitive functioning in healthy controls and neuropsychiatric patients were included. Cognitive tasks were categorized in tasks assessing memory, attention, and executive functioning. Evaluation of 188 trials showed that anodal vs. sham tDCS significantly decreased response times and increased accuracy, and specifically for the executive functioning tasks, in a sample of healthy participants and neuropsychiatric patients (although a slightly different pattern of improvement was found in analyses for both samples separately). The effects of cathodal vs. sham tDCS (45 trials), on the other hand, were not significant. IBS ranged from less than 1 h to up to 1 week (i.e. cathodal tDCS) or 2 weeks (i.e. anodal tDCS). This IBS length had no influence on the estimated effect size when performing a meta-regression of IBS on reaction time and accuracy outcomes in all three cognitive categories, both for anodal and cathodal stimulation. Practical recommendations and limitations of the study are further discussed.
Tolerance to Effects of Cocaine on Behavior under a Response-Initiated Fixed-Interval Schedule
ERIC Educational Resources Information Center
Weaver, Matthew T.; Branch, Marc N.
2008-01-01
Tolerance to effects of cocaine can be modulated by schedules of reinforcement. With multiple ratio schedules, research has shown an inverse relationship between ratio requirement and amount of tolerance that resulted from daily administration of the drug. In contrast, tolerance to the effects of cocaine on behavior under multiple interval…
Maignen, François; Hauben, Manfred; Dogné, Jean-Michel
2017-07-01
The lower bound of the 95% confidence interval of measures of disproportionality (Lower95CI) is widely used in signal detection. Masking is a statistical issue by which true signals of disproportionate reporting are hidden by the presence of other medicines. The primary objective of our study is to develop and validate a mathematical framework for assessing the masking effect of Lower95CI. We have developed our new algorithm based on the masking ratio (MR) developed for the measures of disproportionality. A MR for the Lower95CI (MRCI) is proposed. A simulation study to validate this algorithm was also conducted. We have established the existence of a very close mathematical relation between MR and MRCI. For a given drug-event pair, the same product will be responsible for the highest masking effect with the measure of disproportionality and its Lower95CI. The extent of masking is likely to be very similar across the two methods. An important proportion of identical drug-event associations affected by the presence of an important masking effect is revealed by the unmasking exercise, whether the proportional reporting ratio (PRR) or its confidence interval are used. The detection of the masking effect of Lower95CI can be automated. The real benefits of this unmasking in terms of new true-positive signals (rate of true-positive/false-positive) or time gained by the revealing of signals using this method have not been fully assessed. These benefits should be demonstrated in the context of prospective studies.
Foo, Lee Kien; McGree, James; Duffull, Stephen
2012-01-01
Optimal design methods have been proposed to determine the best sampling times when sparse blood sampling is required in clinical pharmacokinetic studies. However, the optimal blood sampling time points may not be feasible in clinical practice. Sampling windows, a time interval for blood sample collection, have been proposed to provide flexibility in blood sampling times while preserving efficient parameter estimation. Because of the complexity of the population pharmacokinetic models, which are generally nonlinear mixed effects models, there is no analytical solution available to determine sampling windows. We propose a method for determination of sampling windows based on MCMC sampling techniques. The proposed method attains a stationary distribution rapidly and provides time-sensitive windows around the optimal design points. The proposed method is applicable to determine sampling windows for any nonlinear mixed effects model although our work focuses on an application to population pharmacokinetic models.
Estey, Mathew P; Cohen, Ashley H; Colantonio, David A; Chan, Man Khun; Marvasti, Tina Binesh; Randell, Edward; Delvin, Edgard; Cousineau, Jocelyne; Grey, Vijaylaxmi; Greenway, Donald; Meng, Qing H; Jung, Benjamin; Bhuiyan, Jalaluddin; Seccombe, David; Adeli, Khosrow
2013-09-01
The CALIPER program recently established a comprehensive database of age- and sex-stratified pediatric reference intervals for 40 biochemical markers. However, this database was only directly applicable for Abbott ARCHITECT assays. We therefore sought to expand the scope of this database to biochemical assays from other major manufacturers, allowing for a much wider application of the CALIPER database. Based on CLSI C28-A3 and EP9-A2 guidelines, CALIPER reference intervals were transferred (using specific statistical criteria) to assays performed on four other commonly used clinical chemistry platforms including Beckman Coulter DxC800, Ortho Vitros 5600, Roche Cobas 6000, and Siemens Vista 1500. The resulting reference intervals were subjected to a thorough validation using 100 reference specimens (healthy community children and adolescents) from the CALIPER bio-bank, and all testing centers participated in an external quality assessment (EQA) evaluation. In general, the transferred pediatric reference intervals were similar to those established in our previous study. However, assay-specific differences in reference limits were observed for many analytes, and in some instances were considerable. The results of the EQA evaluation generally mimicked the similarities and differences in reference limits among the five manufacturers' assays. In addition, the majority of transferred reference intervals were validated through the analysis of CALIPER reference samples. This study greatly extends the utility of the CALIPER reference interval database which is now directly applicable for assays performed on five major analytical platforms in clinical use, and should permit the worldwide application of CALIPER pediatric reference intervals. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.
Cuervo-Arango, J; Mateu-Sánchez, S; Aguilar, J J; Nielsen, J M; Etcharren, V; Vettorazzi, M L; Newcombe, J R
2015-05-01
The objective of this study was to determine the effect of the interval from induced luteolysis to ovulation on fertility of mares from two different farms. At farm 1, 215 mares were inseminated with frozen/thawed semen during 513 estrous cycles over seven consecutive breeding seasons. Estrus was induced with analogues of PGF2α in 179 cycles. At farm 2, 375 embryo flushings were performed in 65 donor mares inseminated with fresh semen; of which, 327 were performed following artificial insemination after PGF-induced luteolysis. In both farms, the intervals from PGF treatment to ovulation (ITO) data were divided into three interval groups: less than 6 days, 6 to 8 days, and greater than 8 days. A mixed regression model was created to determine the effect of different factors on the pregnancy rate (PR) and embryo recovery rate (ERR). Of all factors analyzed, the ITO was the only one that significantly influenced the PR and ERR (P < 0.05). In farm 1, the PR of mares with an ITO of less than 6 days, 6 to 8 days, and greater than 8 days was 26.6%, 39.4%, and 55.9%, respectively (P = 0.01). The PR for mares inseminated after spontaneous luteolysis (without PGF) was 42.5%. In farm 2, the ERR of donor mares for the same ITO groups was 55.0%, 62.6%, and 73.7%, respectively (P = 0.02). The ERR for mares flushed after a previous spontaneous estrus was 75.0%. In conclusion, the ITO had a significant effect on the PR and ERR in the mare. Fertility was reduced as the ITO became shorter.
How to learn effectively in medical school: test yourself, learn actively, and repeat in intervals.
Augustin, Marc
2014-06-01
Students in medical school often feel overwhelmed by the excessive amount of factual knowledge they are obliged to learn. Although a large body of research on effective learning methods is published, scientifically based learning strategies are not a standard part of the curriculum in medical school. Students are largely unaware of how to learn successfully and improve memory. This review outlines three fundamental methods that benefit learning: the testing effect, active recall, and spaced repetition. The review summarizes practical learning strategies to learn effectively and optimize long-term retention of factual knowledge.
Liu, Jun; Wang, Yongsheng; Su, Jianmin; Wang, Lijun; Li, Ruizhe; Li, Qian; Wu, Yongyan; Hua, Song; Quan, Fusheng; Guo, Zekun; Zhang, Yong
2013-04-01
Previous studies have shown that the time interval between fusion and activation (FA interval) play an important role in nuclear remodeling and in vitro development of somatic cell nuclear transfer (SCNT) embryos. However, the effects of FA interval on the epigenetic reprogramming and in vivo developmental competence of SCNT embryos remain unknown. In the present study, the effects of different FA intervals (0 h, 2 h, and 4 h) on the epigenetic reprogramming and developmental competence of bovine SCNT embryos were assessed. The results demonstrated that H3 lysine 9 (H3K9ac) levels decreased rapidly after fusion in all three groups. H3K9ac was practically undetectable 2 h after fusion in the 2-h and 4-h FA interval groups. However, H3K9ac was still evidently detectable in the 0-h FA interval group. The H3K9ac levels increased 10 h after fusion in all three groups, but were higher in the 2-h and 4-h FA interval groups than that in the 0-h FA interval group. The methylation levels of the satellite I region in day-7 blastocysts derived from the 2-h or 4-h FA interval groups was similar to that of in vitro fertilization blastocysts and is significantly lower than that of the 0-h FA interval group. SCNT embryos derived from 2-h FA interval group showed higher developmental competence than those from the 0-h and 4-h FA interval groups in terms of cleavage rate, blastocyst formation rate, apoptosis index, and pregnancy and calving rates. Hence, the FA interval is an important factor influencing the epigenetic reprogramming and developmental competence of bovine SCNT embryos.
Sampling strategies for estimating brook trout effective population size
Andrew R. Whiteley; Jason A. Coombs; Mark Hudy; Zachary Robinson; Keith H. Nislow; Benjamin H. Letcher
2012-01-01
The influence of sampling strategy on estimates of effective population size (Ne) from single-sample genetic methods has not been rigorously examined, though these methods are increasingly used. For headwater salmonids, spatially close kin association among age-0 individuals suggests that sampling strategy (number of individuals and location from...
Forkman, Johannes
2017-06-15
Linear mixed-effects models are linear models with several variance components. Models with a single random-effects factor have two variance components: the random-effects variance, i. e., the inter-subject variance, and the residual error variance, i. e., the intra-subject variance. In many applications, it is practice to report variance components as coefficients of variation. The intra- and inter-subject coefficients of variation are the square roots of the corresponding variances divided by the mean. This article proposes methods for computing confidence intervals for intra- and inter-subject coefficients of variation using generalized pivotal quantities. The methods are illustrated through two examples. In the first example, precision is assessed within and between runs in a bioanalytical method validation. In the second example, variation is estimated within and between main plots in an agricultural split-plot experiment. Coverage of generalized confidence intervals is investigated through simulation and shown to be close to the nominal value.
Vandbakk, Kristine; Welde, Boye; Kruken, Andrea Hovstein; Baumgart, Julia; Ettema, Gertjan; Karlsen, Trine; Sandbakk, Øyvind
2017-01-01
This study compared the effects of adding upper-body sprint-intervals or continuous double poling endurance training to the normal training on maximal upper-body strength and endurance capacity in female cross-country skiers. In total, 17 female skiers (age: 18.1±0.8yr, body mass: 60±7 kg, maximal oxygen uptake (VO2max): 3.30±0.37 L.min-1) performed an 8-week training intervention. Here, either two weekly sessions of six to eight 30-s maximal upper-body double poling sprint-intervals (SIG, n = 8) or 45-75 min of continuous low-to-moderate intensity double poling on roller skis (CG, n = 9) were added to their training. Before and after the intervention, the participants were tested for physiological and kinematical responses during submaximal and maximal diagonal and double poling treadmill roller skiing. Additionally, we measured maximal upper-body strength (1RM) and average power at 40% 1RM in a poling-specific strength exercise. SIG improved absolute VO2max in diagonal skiing more than CG (8% vs 2%, p<0.05), and showed a tendency towards higher body-mass normalized VO2max (7% vs 2%, p = 0.07). Both groups had an overall improvement in double poling peak oxygen uptake (10% vs 6% for SIG and CG) (both p<0.01), but no group-difference was observed. SIG improved 1RM strength more than CG (18% vs 10%, p<0.05), while there was a tendency for difference in average power at 40% 1RM (20% vs 14%, p = 0.06). Oxygen cost and kinematics (cycle length and rate) in double poling and diagonal remained unchanged in both groups. In conclusion, our study demonstrates that adding upper-body sprint-interval training is more effective than continuous endurance training in improving upper-body maximal strength and VO2max.
Zupanic, Eva; Zivanovic, Ina; Kalisnik, Jurij Matija; Avbelj, Viktor; Lainscak, Mitja
2014-12-01
Chronic obstructive pulmonary disease negatively affects the autonomic nervous system and increases risks of arrhythmias and sudden cardiac death. Electrocardiogram (ECG) recordings were used to compare parameters of heart rate variability and QTc interval in patients with COPD and healthy individuals. The effects of a 4-week program of rehabilitation in patients with COPD were also evaluated by comparing pre- and post-rehabilitation ECGs with age- and sex-matched control COPD patients not participating in the program. Heart rate, average NN, SDNN, RMSSD, pNN50, TP, LF, HF, LF/HF, and QTc were analyzed. Rehabilitation effects were evaluated using the St. George's respiratory questionnaire (SGRQ), the 6-min walk test (6MWT), and the incremental shuttle walking test (ISWT). In comparison with the healthy individuals, the patients with COPD had higher heart rate (p < 0.05) and reduced average NN, SDNN, RMSSD, pNN50, HF, LF, and TP (all p < 0.05) but similar QTc interval (p = 0.185). During rehabilitation, SDNN and TP (p < 0.05 for both) increased, as did the results for 6MWT, ISWT, and SGRQ (all p < 0.05). No significant change of QTc interval was observed within or between the two groups of patients with COPD. Change in SDNN correlated with a clinically relevant difference in SGRQ (r = 0.538, p = 0.021). It is concluded that patients with COPD demonstrate reduced parameters of heart rate variability and that these can be improved in a rehabilitation program, thus improving health-related quality of life.
Teixeira, Anderson S; Arins, Francimara B; De Lucas, Ricardo D; Carminatti, Lorival J; Dittrich, Naiandra; Nakamura, Fábio Yuzo; Guglielmo, Luiz Guilherme A
2017-09-06
The purpose of the present study was to analyze the effects of two shuttle-run interval training (SRIT) models with one and three directional changes per running bout on the aerobic and anaerobic performances of elite female futsal players. Sixteen players competing in the Brazilian National Division League took part in the study. The training protocols consisted of shuttle-run intervals organized in four sets of 4-min bouts with 3- min of rest intervals between the sets. The SRIT models were composed of one (7.5 s running and 7.5 s pause [SRIT7.5x7.5]; n=7) or three (15 s running and 15 s pause [SRIT15x15]; n=9) directional changes. The athletes performed the following tests before and after a 5-week training period: incremental treadmill test (ITT), Futsal Intermittent Endurance Test (FIET) [with respective peak speeds (PS)] and a repeated sprint ability (RSA) test. After the training period, PSFIET and speed at the second lactate turnpoint were very likely and almost certainly increased in both training regimens, respectively. SRIT15x15 induced possibly greater improvements in PSITT (+3.28%, 90%CL -0.16 to 6.82) and RSAmean (+1.17%, 90% CL -0.68 to 3.05) than SRIT7.5x7.5. In addition, SRIT15x15 resulted in a likely greater improvement in running economy (+4.33%, 90% CL -0.35 to 9.23) compared with SRIT7.5x7.5. In elite female futsal players, SRIT15x15 is a promising strategy to enhance performance-related physical fitness attributes in a shortterm period (5 weeks) during the preseason, due to its superior effects on these important aerobic and anaerobic qualities than a protocol with fewer directional changes.
ERIC Educational Resources Information Center
Taub, Gordon E.; McGrew, Kevin S.; Keith, Timothy Z.
2015-01-01
This article examines the effect of improvements in timing/rhythmicity on mathematics achievement. A total of 86 participants attending 1st through 4th grades completed pre- and posttest measures of mathematics achievement from the Woodcock-Johnson III Tests of Achievement. Students in the experimental group participated in a 4-week intervention…
ERIC Educational Resources Information Center
Taub, Gordon E.; McGrew, Kevin S.; Keith, Timothy Z.
2015-01-01
This article examines the effect of improvements in timing/rhythmicity on mathematics achievement. A total of 86 participants attending 1st through 4th grades completed pre- and posttest measures of mathematics achievement from the Woodcock-Johnson III Tests of Achievement. Students in the experimental group participated in a 4-week intervention…
Effects of posture on exercise performance - Measurement by systolic time intervals.
NASA Technical Reports Server (NTRS)
Spodick, D. H.; Quarry-Pigott, V. M.
1973-01-01
Because posture significantly influences cardiac performance, the effects of moderate supine and upright ergometer exercise were compared on the basis of proportional (+37%) rate increments over resting control. Supine exercise produced significant decreases in left ventricular ejection time (LVET), pre-ejection period (PEP), and isovolumic contraction time (IVCT). Ejection time index (ETI) and corrected ejection time (LVETc) did not change significantly. Upright exercise produced greater decreases in PEP and LVET, but despite the rate increase there was no change in LVET, which resulted in sharp increases in ETI and LVETc. The discordant directional effects on LVET and its rate-correcting indices between the two postures were consistent with hemodynamic studies demonstrating lack of stroke volume change during supine exercise and increased stroke volume over control during light to moderate upright exercise.
Hayashi, Yusuke; Hall, Sarah E.; Williams, Dean C.
2013-01-01
The present study investigated effects of signaled reinforcer magnitude in a delayed identity matching-to-sample procedure. Four individuals with intellectual disabilities were trained on conditional discrimination with three geometric stimuli as sample and comparison stimuli. Retention intervals ranged from 0.1 to 16 s. The magnitude of the reinforcer (different durations of access to a video game) was signaled by the background color of the screen. Matching accuracy was overall higher when the larger reinforcer was signaled, independently of retention intervals. PMID:23523782
Wood, David B.
2007-11-01
Between 1951 and 1992, 828 underground tests were conducted on the Nevada National Security Site, Nye County, Nevada. Prior to and following these nuclear tests, holes were drilled and mined to collect rock samples. These samples are organized and stored by depth of borehole or drift at the U.S. Geological Survey Core Library and Data Center at Mercury, Nevada, on the Nevada National Security Site. From these rock samples, rock properties were analyzed and interpreted and compiled into project files and in published reports that are maintained at the Core Library and at the U.S. Geological Survey office in Henderson, Nevada. These rock-sample data include lithologic descriptions, physical and mechanical properties, and fracture characteristics. Hydraulic properties also were compiled from holes completed in the water table. Rock samples are irreplaceable because pre-test, in-place conditions cannot be recreated and samples can not be recollected from the many holes destroyed by testing. Documenting these data in a published report will ensure availability for future investigators.
David B. Wood
2007-10-24
Between 1951 and 1992, 828 underground tests were conducted on the Nevada Test Site, Nye County, Nevada. Prior to and following these nuclear tests, holes were drilled and mined to collect rock samples. These samples are organized and stored by depth of borehole or drift at the U.S. Geological Survey Core Library and Data Center at Mercury, Nevada, on the Nevada Test Site. From these rock samples, rock properties were analyzed and interpreted and compiled into project files and in published reports that are maintained at the Core Library and at the U.S. Geological Survey office in Henderson, Nevada. These rock-sample data include lithologic descriptions, physical and mechanical properties, and fracture characteristics. Hydraulic properties also were compiled from holes completed in the water table. Rock samples are irreplaceable because pre-test, in-place conditions cannot be recreated and samples cannot be recollected from the many holes destroyed by testing. Documenting these data in a published report will ensure availability for future investigators.
David B. Wood
2009-10-08
Between 1951 and 1992, underground nuclear weapons testing was conducted at 828 sites on the Nevada Test Site, Nye County, Nevada. Prior to and following these nuclear tests, holes were drilled and mined to collect rock samples. These samples are organized and stored by depth of borehole or drift at the U.S. Geological Survey Core Library and Data Center at Mercury, Nevada, on the Nevada Test Site. From these rock samples, rock properties were analyzed and interpreted and compiled into project files and in published reports that are maintained at the Core Library and at the U.S. Geological Survey office in Henderson, Nevada. These rock-sample data include lithologic descriptions, physical and mechanical properties, and fracture characteristics. Hydraulic properties also were compiled from holes completed in the water table. Rock samples are irreplaceable because pre-test, in-place conditions cannot be recreated and samples cannot be recollected from the many holes destroyed by testing. Documenting these data in a published report will ensure availability for future investigators.
Angenstein, Nicole; Scheich, Henning; Brechmann, André
2012-07-02
The processing of pitch intervals may be differentially influenced when musical or speech stimuli carry the pitch information. Most insights into the neural basis of pitch interval processing come from studies on music perception. However, music, in contrast to speech, contains a stable set of pitch intervals. To converge the investigation of pitch interval processing in music and speech, we used sequences of the same spoken or sung syllables. The pitch of these syllables varied either by semitone steps like in music or by smaller intervals. Participants had to differentiate the sequences according to their different sizes of pitch intervals or to the direction of the last frequency step in the sequence. The results depended strongly on the specific task demands. Whereas the interval-size task itself recruited more regions in right lateralized fronto-parietal brain network, stronger activity on semitone than on non-semitone sequences was found in the left hemisphere (mainly in frontal cortex) during this task. These effects were also influenced by the speech mode (spoken or sung syllables). Our findings suggest that the processing of pitch intervals in sequences of syllables depends on an interaction between bottom-up (speech mode, pitch interval) and top-down effects (task). Copyright © 2012 Elsevier Inc. All rights reserved.
Lukkari, E; Aranko, K; Juhakoski, A; Hakonen, T; Neuvonen, P J
1997-07-01
The effect of time interval between food and drug ingestion on the bioavailability of oxybutynin was investigated in a randomized, three-phase cross-over study in 31 healthy volunteers. The serum concentrations of oxybutynin and the metabolite, N-desethyloxybutynin were measured up to 48 hr after ingestion of a controlled-release 10 mg oxybutynin tablet either in fasting state, 2 hr after breakfast or 1 hr before. The Cmax of both oxybutynin (P < 0.0001) and N-desethyloxybutynin (P < 0.0001) and the AUC0-1 of N-desethyloxybutynin (P < 0.05) were significantly larger when oxybutynin was ingested 2 hr after breakfast, than during the fasting, but the AUC0-1 of oxybutynin remained unchanged. Breakfast ingested 1 hr after oxybutynin did not affect the pharmacokinetic parameters of oxybutynin or N-desethyloxybutynin. The saliva secretion rate decreased slightly more (P < 0.05), when oxybutynin was administered 2 hr after breakfast than during fasting. The effect of food ingestion on the serum concentrations of oxybutynin and N-desethyloxybutynin is expected to have minor clinical significance only. However, ingestion of the controlled-release tablet 1 hr before meal increases the likelihood of obtaining constant drug levels with lower peak concentrations during the dosage interval, and thus ingestion of the controlled-release tablet 0.5-1 hr before food may well improve tolerability and compliance in patients who suffer from adverse reactions.
Saberi, Kourosh; Antonio, Joseph V
2003-07-01
Data are reported from 127 untrained individuals under lag- and single-click conditions in a precedence-effect task. In experiment I, each subject completed ten runs in a two-interval forced-choice design under a lag-click condition and three runs under a single-click condition. The cue to be discriminated was an interaural time difference (ITD). Stimuli were 125-micros rectangular pulses and the interclick interval (ICI) was 2 ms. Subjects were randomly assigned to three groups of approximately 30. Each group was tested at one stimulus intensity (43, 58, or 73 dB). Mean threshold within each group was greater than 500 micros for lag-click ITD conditions, although substantial intersubject variability and a clear effect of stimulus intensity on lag-click ITD thresholds were observed, with lower thresholds for higher intensities. In experiment II, the ICI was varied from 0.3 to 10 ms, and thresholds were obtained from groups of approximately 20 untrained subjects. Data were also collected from three highly experienced observers as a function of ICI. The best naive subject produced mean thresholds near, but not as low as those obtained from experienced subjects. Analysis of adaptive-track patterns revealed abrupt irregularities in threshold tracking, consistent with either losing the cue or listening to the wrong cue in an ambiguous stimulus.
Rosol, Zachary; Miranda, David F; Sandoval, Yader; Bart, Bradley A; Smith, Stephen W; Goldsmith, Steven R
2017-06-01
Targeted Temperature Management (TTM) improves outcomes after cardiac arrest but may affect the QT and QTc intervals which could increase the chance of subsequent arrhythmia. We report here the effects of TTM on both computer-derived and manually calculated QT and QTc as well as the relationship of the length of the QTc and serious arrhythmia in a retrospective single-center experience. 193 patients undergoing TTM for cardiac arrest were studied. 12-lead electrocardiograms (ECG) were measured before, during and after TTM. We assessed the QT and Bazett-corrected QT intervals (QTc) and examined the relationship between QTc and the occurrence of malignant arrhythmias. Both the QT and QTc increased during TTM whether derived manually or from the computer algorithm, although values were different with the two methods. Neither the QT nor the QTc were significantly longer in those patients with malignant arrhythmias. QT and QTc prolong during TTM. There was no differential increase in the QTc in patients who experienced malignant arrhythmias. While the mechanism of QTc prolongation is not clear, it would not appear that the degree of QTc prolongation has an adverse effect on cardiac rhythm during TTM. Copyright © 2017 Elsevier Inc. All rights reserved.
Büyükyazi, G; Karamizrak, S O; Islegen, C
2003-01-01
Effects of two different eight-week aerobic training programs consisting of continuous (CR) or extensive interval running (IR) on serum growth (GH) and cortisol hormones in 33 male basketball players aged 15-16 were assessed. The CR group ran 4.8 km and the IR group ran 4 x 1.2 km, using equal work-to-rest ratio, three times per week. Aerobic power scores of all subjects and anaerobic power marks of the training subjects increased (p<0.01). Upon exertion, though serum GH levels increased in both exercise groups (p<0.01) prior to and following training; cortisol levels increased only in the IR group prior to training, and in both exercise groups following training (p<0.05). Following the eight week period, resting cortisol levels rose in the training (p<0.05) and control (p<0.01) groups. To conclude, an 8-week training program consisting of continuous or extensive interval running has been effective on acute GH and cortisol secretion in 15-16 year-old male athletes.
ERIC Educational Resources Information Center
Hinderliter, Charles F.; Andrews, Amy; Misanin, James R.
2012-01-01
In conditioned taste aversion (CTA), a taste, the conditioned stimulus (CS), is paired with an illness-inducing stimulus, the unconditioned stimulus (US), to produce CS-US associations at very long (hours) intervals, a result that appears to violate the law of contiguity. The specific length of the maximum effective trace interval that has been…
ERIC Educational Resources Information Center
Hinderliter, Charles F.; Andrews, Amy; Misanin, James R.
2012-01-01
In conditioned taste aversion (CTA), a taste, the conditioned stimulus (CS), is paired with an illness-inducing stimulus, the unconditioned stimulus (US), to produce CS-US associations at very long (hours) intervals, a result that appears to violate the law of contiguity. The specific length of the maximum effective trace interval that has been…
Rønnestad, B R; Hansen, J; Ellefsen, S
2014-02-01
The purpose of this study was to compare the effect of two different methods of organizing endurance training in trained cyclists. One group of cyclists performed block periodization, wherein the first week constituted five sessions of high-intensity aerobic training (HIT), followed by 3 weeks of one weekly HIT session and focus on low-intensity training (LIT) (BP; n = 10, VO2max = 62 ± 2 mL/kg/min). Another group of cyclists performed a more traditional organization, with 4 weeks of two weekly HIT sessions interspersed with LIT (TRAD; n = 9, VO2max = 63 ± 2 mL/kg/min). Similar volumes of both HIT and LIT was performed in the two groups. While BP increased VO2max , peak power output (Wmax) and power output at 2 mmol/L [la(-)] by 4.6 ± 3.7%, 2.1 ± 2.8%, and 10 ± 12%, respectively (P < 0.05), no changes occurred in TRAD. BP showed relative improvements in VO2max compared with TRAD (P < 0.05). Mean effect size (ES) of the relative improvement in VO2max , Wmax , and power output at 2 mmol/L [la(-)] revealed large to moderate effects of BP training compared with TRAD training (ES = 1.34, ES = 0.85, and ES = 0.71, respectively). The present study suggests that block periodization of training provides superior adaptations to traditional organization during a 4-week endurance training period, despite similar training volume and intensity. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
USDA-ARS?s Scientific Manuscript database
Stillbirth in swine ranges from 2 to 9%, resulting in a significant loss of piglets. Previous studies clearly indicate a relationship between prolonged birth intervals and stillbirth, but factors influencing birth intervals are not fully known. To characterize birth intervals and stillbirth, farrowi...
Weller, Lisa; Schwarz, Katharina A; Kunde, Wilfried; Pfister, Roland
2017-02-01
Sensory stimuli resulting from one's own actions are perceptually attenuated compared to identical but externally produced stimuli. This may enable the organism to discriminate between self-produced events and externally produced events, suggesting a strong link between sensory attenuation and a subjective sense of agency. To investigate this supposed link, we compared the influence of filled and unfilled action-effect delays on both, judgements of agency for self-produced sounds and attenuation of the event-related potential (ERP). In line with previous findings, judgments of agency differed between both delay conditions with higher ratings for filled than for unfilled delays. Sensory attenuation, however, was not influenced by filling the delay. These findings indicate a partial dissociation of the two phenomena.
The effect of pulse interval statistics on the spectrum of radiation from lightning
NASA Technical Reports Server (NTRS)
Le Vine, D. M.
1977-01-01
An analysis of atmospheric radio noise originally appearing in the literature to describe the VLF structure of atmospherics is repeated here, keeping a term discarded in the previous work and extending the results to include all frequencies and some simple effects of amplitude variations. It is shown that at high frequencies, atmospheric radiation appears to be the result of incoherent sources, whereas at low frequencies the sferics appear to originate from coherent sources. These conclusions are valid with only weak restrictions, regardless of the actual statistical model assumed for the process. An implication of these results is that at high frequencies the magnitude of the spectrum of the received signal can be related to the spectrum of the source current, a means for the study of lightning current wave forms thus possibly being provided.
Weston, Matthew; Weston, Kathryn L; Prentis, James M; Snowden, Chris P
2016-01-01
The advancement of perioperative medicine is leading to greater diversity in development of pre-surgical interventions, implemented to reduce patient surgical risk and enhance post-surgical recovery. Of these interventions, the prescription of pre-operative exercise training is gathering momentum as a realistic means for enhancing patient surgical outcome. Indeed, the general benefits of exercise training have the potential to pre-operatively optimise several pre-surgical risks factors, including cardiorespiratory function, frailty and cognitive function. Any exercise programme incorporated into the pre-operative pathway of care needs to be effective and time efficient in that any fitness gains are achievable in the limited period between the decision for surgery and operation (e.g. 4 weeks). Fortunately, there is a large volume of research describing effective and time-efficient exercise training programmes within the discipline of sports science. Accordingly, the objective of our commentary is to synthesise contemporary exercise training research, both from non-clinical and clinical populations, with the overarching aim of informing the development of effective and time-efficient pre-surgical exercise training programmes. The development of such exercise training programmes requires the careful consideration of several key principles, namely frequency, intensity, time, type and progression of exercise. Therefore, in light of more recent evidence demonstrating the effectiveness and time efficiency of high-intensity interval training-which involves brief bouts of intense exercise interspersed with longer recovery periods-the principles of exercise training programme design will be discussed mainly in the context of such high-intensity interval training programmes. Other issues pertinent to the development, implementation and evaluation of pre-operative exercise training programmes, such as individual exercise prescription, training session monitoring and potential
Alternative Confidence Interval Methods Used in the Diagnostic Accuracy Studies.
Erdoğan, Semra; Gülhan, Orekıcı Temel
2016-01-01
Background/Aim. It is necessary to decide whether the newly improved methods are better than the standard or reference test or not. To decide whether the new diagnostics test is better than the gold standard test/imperfect standard test, the differences of estimated sensitivity/specificity are calculated with the help of information obtained from samples. However, to generalize this value to the population, it should be given with the confidence intervals. The aim of this study is to evaluate the confidence interval methods developed for the differences between the two dependent sensitivity/specificity values on a clinical application. Materials and Methods. In this study, confidence interval methods like Asymptotic Intervals, Conditional Intervals, Unconditional Interval, Score Intervals, and Nonparametric Methods Based on Relative Effects Intervals are used. Besides, as clinical application, data used in diagnostics study by Dickel et al. (2010) has been taken as a sample. Results. The results belonging to the alternative confidence interval methods for Nickel Sulfate, Potassium Dichromate, and Lanolin Alcohol are given as a table. Conclusion. While preferring the confidence interval methods, the researchers have to consider whether the case to be compared is single ratio or dependent binary ratio differences, the correlation coefficient between the rates in two dependent ratios and the sample sizes.
Sub-Nyquist artefacts and sampling moiré effects
Amidror, Isaac
2015-01-01
Sampling moiré effects are well known in signal processing. They occur when a continuous periodic signal g(x) is sampled using a sampling frequency fs that does not respect the Nyquist condition, and the signal-frequency f folds over and gives a new, false low frequency in the sampled signal. However, some visible beating artefacts may also occur in the sampled signal when g(x) is sampled using a sampling frequency fs which fully respects the Nyquist condition. We call these phenomena sub-Nyquist artefacts. Although these beating effects have already been reported in the literature, their detailed mathematical behaviour is not widely known. In this paper, we study the behaviour of these phenomena and compare it with analogous results from the moiré theory. We show that both sampling moirés and sub-Nyquist artefacts obey the same basic mathematical rules, in spite of the differences between them. This leads us to a unified approach that explains all of these phenomena and puts them under the same roof. In particular, it turns out that all of these phenomena occur when the signal-frequency f and the sampling frequency fs satisfy f≈(m/n)fs with integer m, n, where m/n is a reduced integer ratio; cases with n=1 correspond to true sampling moiré effects. PMID:26064621
Kwon, Yong Ung; Blaise Williams, D S
2017-04-01
Inadequate rest intervals may contribute to impaired performance during functional tests. However, the effect of different rest intervals on performance of the SEBT in individuals with and without CAI is not known. Our purposes were to determine whether different rest intervals impact ankle kinematics during the SEBT and whether there differences between those two populations. 24 controls and 24 CAI completed 3 trials in 3 reach directions (anteromedial; AM, medial; M, posteromedial; PM). The order of rest intervals and reach distance were randomized and counterbalanced. Three visits were required to complete the 3 rest interval conditions (10, 20, 40s). Rest interval did not impact ankle kinematics between controls and CAI during the SEBT. Dorsiflexion (DF) (AM:partial η(2)=0.18; M:partial η(2)=0.23; PM:partial η(2)=0.23) for all directions and tibial internal rotation (TIR) excursions (AM:partial η(2)=0.20) for AM direction were greater in individuals with CAI regardless of rest interval length. Rest intervals ranging from 10 to 40s did not influence ankle kinematics. Differences exist in DF and TIR between controls and CAI during the SEBT. These findings suggest that clinicians can use any rest interval between 10 and 40s when administrating the SEBT. However, triplanar motion differs during a complex functional movement in controls compared to CAI. Copyright © 2017 Elsevier B.V. All rights reserved.
Effects of High Intensity Interval Training on Fat Mass Parameters in Adolescents.
Camacho-Cardenosa, Alba; Brazo-Sayavera, Javier; Camacho-Cardenosa, Marta; Marcos-Serrano, Marta; Timón, Rafael; Olcina, Guillermo
2016-11-21
Childhood and adolescence are key to the development of chronic disease stages, the distribution of fat an important factor in this regard. The aim of the study was to evaluate the effects on fat parameters of a high intensity program developed in adolescents during physical education classes. In 2013, 35 school-age children of Cáceres taken part in this study divided into two groups. The high-intensity group performed for 8 weeks, 4-6 sets of 20 seconds at maximal intensity with a ratio effort / recovery of 1: 3 to 1: 1. The other group, developed continuous aerobic exercise during the same time. It conducted an assessment of fat mass before and after the training program. Repeated measures ANOVA test was used to observe that there were no statistically significant differences. Continuous aerobic training group showed statistically significant differences in intra-group analysis in the percentage of fat mass trunk (Pre: 15.66 ± 4.16 vs Post: 16.95 ± 4.03; +1, 29%; p = 0.04) and the percentage of total fat (Pre: 21.58 ± 3.93 / Post: 22.34 ± 3.70; p = 0.05). Statistically significant differences were not found in the analysis between-groups in any of the studied variables. The training program high intensity physical activity at school carried out during physical education classes did not improve fat mass parameters evaluated. However, maintaining these parameters could be a good result during the development of this stage, where an increase of these occurs.
Neeman, Noga; Spotila, James R; O'Connor, Michael P
2015-09-07
Variation in the yearly number of sea turtles nesting at rookeries can interfere with population estimates and obscure real population dynamics. Previous theoretical models suggested that this variation in nesting numbers may be driven by changes in resources at the foraging grounds. We developed a physiologically-based model that uses temperatures at foraging sites to predict foraging conditions, resource accumulation, remigration probabilities, and, ultimately, nesting numbers for a stable population of sea turtles. We used this model to explore several scenarios of temperature variation at the foraging grounds, including one-year perturbations and cyclical temperature oscillations. We found that thermally driven resource variation can indeed synchronize nesting in groups of turtles, creating cohorts, but that these cohorts tend to break down over 5-10 years unless regenerated by environmental conditions. Cohorts were broken down faster at lower temperatures. One-year perturbations of low temperature had a synchronizing effect on nesting the following year, while high temperature perturbations tended to delay nesting in a less synchronized way. Cyclical temperatures lead to cyclical responses both in nesting numbers and remigration intervals, with the amplitude and lag of the response depending on the duration of the cycle. Overall, model behavior is consistent with observations at nesting beaches. Future work should focus on refining the model to fit particular nesting populations and testing further whether or not it may be used to predict observed nesting numbers and remigration intervals. Copyright © 2015 Elsevier Ltd. All rights reserved.
Vink, Arja S; Clur, Sally-Ann B; Geskus, Ronald B; Blank, Andreas C; De Kezel, Charlotte C A; Yoshinaga, Masao; Hofman, Nynke; Wilde, Arthur A M; Blom, Nico A
2017-04-01
In congenital long-QT syndrome, age, sex, and genotype have been associated with cardiac events, but their effect on the trend in QTc interval has never been established. We, therefore, aimed to assess the effect of age and sex on the QTc interval in children and adolescents with type 1 (LQT1) and type 2 (LQT2) long-QT syndrome. QTc intervals of 12-lead resting electrocardiograms were determined, and trends over time were analyzed using a linear mixed-effects model. The study included 278 patients with a median follow-up of 4 years (interquartile range, 1-9) and a median number of 6 (interquartile range, 2-10) electrocardiograms per patient. Both LQT1 and LQT2 male patients showed QTc interval shortening after the onset of puberty. In LQT2 male patients, this was preceded by a progressive QTc interval prolongation. In LQT1, after the age of 12 years, male patients had a significantly shorter QTc interval than female patients. In LQT2, during the first years of life and from 14 to 26 years, male patients had a significantly shorter QTc interval than female patients. On the contrary, between 5 and 14 years, LQT2 male patients had significantly longer QTc interval than LQT2 female patients. There is a significant effect of age and sex on the QTc interval in long-QT syndrome, with a unique pattern per genotype. The age of 12 to 14 years is an important transitional period. In the risk stratification and management of long-QT syndrome patients, clinicians should be aware of these age-, sex-, and genotype-related trends in QTc interval and especially the important role of the onset of puberty. © 2017 American Heart Association, Inc.
Karstoft, Kristian; Wallis, Gareth A; Pedersen, Bente K; Solomon, Thomas P J
2016-09-01
For unknown reasons, interval training often reduces body weight more than energy-expenditure matched continuous training. We compared the acute effects of time-duration and oxygen-consumption matched interval- vs. continuous exercise on excess post-exercise oxygen consumption (EPOC), substrate oxidation rates and lipid metabolism in the hours following exercise in subjects with type 2 diabetes (T2D). Following an overnight fast, ten T2D subjects (M/F: 7/3; age=60.3±2.3years; body mass index (BMI)=28.3±1.1kg/m(2)) completed three 60-min interventions in a counterbalanced, randomized order: 1) control (CON), 2) continuous walking (CW), 3) interval-walking (IW - repeated cycles of 3min of fast and 3min of slow walking). Indirect calorimetry was applied during each intervention and repeatedly for 30min per hour during the following 5h. A liquid mixed meal tolerance test (MMTT, 450kcal) was consumed by the subjects 45min after completion of the intervention with blood samples taken regularly. Exercise interventions were successfully matched for total oxygen consumption (CW=1641±133mL/min; IW=1634±126mL/min, P>0.05). EPOC was higher after IW (8.4±1.3l) compared to CW (3.7±1.4l, P<0.05). Lipid oxidation rates were increased during the MMTT in IW (1.03±0.12mg/kg per min) and CW (0.87±0.04mg/kg per min) compared with CON (0.73±0.04mg/kg per min, P<0.01 and P<0.05, respectively), with no difference between IW and CW. Moreover, free fatty acids and glycerol concentrations, and glycerol kinetics were increased comparably during and after IW and CW compared to CON. Interval exercise results in greater EPOC than oxygen-consumption matched continuous exercise during a post-exercise MMTT in subjects with T2D, whereas effects on substrate oxidation and lipid metabolism are comparable. Copyright © 2016 Elsevier Inc. All rights reserved.
Ogungbenro, Kayode; Aarons, Leon
2009-01-01
This paper describes an effective approach for optimizing sampling windows for population pharmacokinetic experiments. Sampling windows has been proposed for population pharmacokinetic experiments that are conducted in late phase drug development programs where patients are enrolled in many centers and out-patient clinic settings. Collection of samples under this uncontrolled environment at fixed times may be problematic and can result in uninformative data. A sampling windows approach is more practicable, as it provides the opportunity to control when samples are collected by allowing some flexibility and yet provide satisfactory parameter estimation. This approach uses D-optimality to specify time intervals around fixed D-optimal time points that results in a specified level of efficiency. The sampling windows have different lengths and achieve two objectives: the joint sampling windows design attains a high specified efficiency level and also reflects the sensitivities of the plasma concentration-time profile to parameters. It is shown that optimal sampling windows obtained using this approach are very efficient for estimating population PK parameters and provide greater flexibility in terms of when samples are collected.
Electrostatic effects in asbestos sampling. I: Experimental measurements.
Baron, P A; Deye, G J
1990-02-01
Electrostatic charge can cause errors during sampling of airborne asbestos fibers and other particles. The change in particle trajectories caused by charge effects during sampling can result in nonuniform deposits on the collecting filter surface and net loss of sample. The degree of these electrostatic effects depends on particle charge, sampler charge, sampler conductivity, and sampling flow rate and direction. The purpose of this research was to evaluate the dependence of sampling efficiency and sample uniformity on these variables. Humidity has been postulated as a primary determinant of particle charge during aerosol generation. Measurements of particle charge and concentration were made as a function of relative humidity with chrysotile fibers generated from a fluidized bed. A strong increase in charge and a decrease in concentration of fibers was noted as the relative humidity was decreased below 15%. The effects of conductive versus nonconductive samplers and sampling flow rate were measured as a function of particle and sampler charge levels. Nonconductive samplers can carry a large and variable charge distribution on their surfaces. This can result in a biased and highly variable particle deposit on the filter when sampling charged particles. Conductive cowls spread any acquired charge over the entire surface and produce a more symmetrical and less biased charged particle deposit. Increasing the sampling flow rate will improve sampling efficiency and decrease deposit variability because the charged particle has less time to interact with the field produced by the sampler. These results suggest that sampling problems caused by electrostatic charge interactions are most likely to occur under low humidity conditions of dust generation, that sampling should be done at as high a flow rate as possible to reduce these effects, and that analysts should select fields toward the center of the filter to minimize bias and variability.
Relativistic effects on galaxy redshift samples due to target selection
NASA Astrophysics Data System (ADS)
Alam, Shadab; Croft, Rupert A. C.; Ho, Shirley; Zhu, Hongyu; Giusarma, Elena
2017-10-01
In a galaxy redshift survey, the objects to be targeted for spectra are selected from a photometrically observed sample. The observed magnitudes and colours of galaxies in this parent sample will be affected by their peculiar velocities, through relativistic Doppler and relativistic beaming effects. In this paper, we compute the resulting expected changes in galaxy photometry. The magnitudes of the relativistic effects are a function of redshift, stellar mass, galaxy velocity and velocity direction. We focus on the CMASS sample from the Sloan Digital Sky Survey (SDSS) and Baryon Oscillation Spectroscopic Survey (BOSS), which is selected on the basis of colour and magnitude. We find that 0.10 per cent of the sample (∼585 galaxies) has been scattered into the targeted region of colour-magnitude space by relativistic effects, and conversely 0.09 per cent of the sample (∼532 galaxies) has been scattered out. Observational consequences of these effects include an asymmetry in clustering statistics, which we explore in a companion paper. Here, we compute a set of weights that can be used to remove the effect of modulations introduced into the density field inferred from a galaxy sample. We conclude by investigating the possible effects of these relativistic modulation on large-scale clustering of the galaxy sample.
Pigeons' Choices between Fixed-Interval and Random-Interval Schedules: Utility of Variability?
ERIC Educational Resources Information Center
Andrzejewski, Matthew E.; Cardinal, Claudia D.; Field, Douglas P.; Flannery, Barbara A.; Johnson, Michael; Bailey, Kathleen; Hineline, Philip N.
2005-01-01
Pigeons' choosing between fixed-interval and random-interval schedules of reinforcement was investigated in three experiments using a discrete-trial procedure. In all three experiments, the random-interval schedule was generated by sampling a probability distribution at an interval (and in multiples of the interval) equal to that of the…
Pigeons' Choices between Fixed-Interval and Random-Interval Schedules: Utility of Variability?
ERIC Educational Resources Information Center
Andrzejewski, Matthew E.; Cardinal, Claudia D.; Field, Douglas P.; Flannery, Barbara A.; Johnson, Michael; Bailey, Kathleen; Hineline, Philip N.
2005-01-01
Pigeons' choosing between fixed-interval and random-interval schedules of reinforcement was investigated in three experiments using a discrete-trial procedure. In all three experiments, the random-interval schedule was generated by sampling a probability distribution at an interval (and in multiples of the interval) equal to that of the…
Performance of Random Effects Model Estimators under Complex Sampling Designs
ERIC Educational Resources Information Center
Jia, Yue; Stokes, Lynne; Harris, Ian; Wang, Yan
2011-01-01
In this article, we consider estimation of parameters of random effects models from samples collected via complex multistage designs. Incorporation of sampling weights is one way to reduce estimation bias due to unequal probabilities of selection. Several weighting methods have been proposed in the literature for estimating the parameters of…
Performance of Random Effects Model Estimators under Complex Sampling Designs
ERIC Educational Resources Information Center
Jia, Yue; Stokes, Lynne; Harris, Ian; Wang, Yan
2011-01-01
In this article, we consider estimation of parameters of random effects models from samples collected via complex multistage designs. Incorporation of sampling weights is one way to reduce estimation bias due to unequal probabilities of selection. Several weighting methods have been proposed in the literature for estimating the parameters of…
Effective sampling range for protein-based lures
USDA-ARS?s Scientific Manuscript database
Effective sampling range is defined as the maximum distance from which an insect can reach an attractive source in a given period of time. Information on sampling range is valuable for determining appropriate coverage of traps for use in population delimitation, mass trapping control strategies, or...
Reference Intervals in Neonatal Hematology.
Henry, Erick; Christensen, Robert D
2015-09-01
The various blood cell counts of neonates must be interpreted in accordance with high-quality reference intervals based on gestational and postnatal age. Using very large sample sizes, we generated neonatal reference intervals for each element of the complete blood count (CBC). Knowledge of whether a patient has CBC values that are too high (above the upper reference interval) or too low (below the lower reference interval) provides important insights into the specific disorder involved and in many instances suggests a treatment plan. Copyright © 2015 Elsevier Inc. All rights reserved.
Effects of sample size and sampling frequency on studies of brown bear home ranges and habitat use
Arthur, Steve M.; Schwartz, Charles C.
1999-01-01
We equipped 9 brown bears (Ursus arctos) on the Kenai Peninsula, Alaska, with collars containing both conventional very-high-frequency (VHF) transmitters and global positioning system (GPS) receivers programmed to determine an animal's position at 5.75-hr intervals. We calculated minimum convex polygon (MCP) and fixed and adaptive kernel home ranges for randomly-selected subsets of the GPS data to examine the effects of sample size on accuracy and precision of home range estimates. We also compared results obtained by weekly aerial radiotracking versus more frequent GPS locations to test for biases in conventional radiotracking data. Home ranges based on the MCP were 20-606 km2 (x = 201) for aerial radiotracking data (n = 12-16 locations/bear) and 116-1,505 km2 (x = 522) for the complete GPS data sets (n = 245-466 locations/bear). Fixed kernel home ranges were 34-955 km2 (x = 224) for radiotracking data and 16-130 km2 (x = 60) for the GPS data. Differences between means for radiotracking and GPS data were due primarily to the larger samples provided by the GPS data. Means did not differ between radiotracking data and equivalent-sized subsets of GPS data (P > 0.10). For the MCP, home range area increased and variability decreased asymptotically with number of locations. For the kernel models, both area and variability decreased with increasing sample size. Simulations suggested that the MCP and kernel models required >60 and >80 locations, respectively, for estimates to be both accurate (change in area <1%/additional location) and precise (CV < 50%). Although the radiotracking data appeared unbiased, except for the relationship between area and sample size, these data failed to indicate some areas that likely were important to bears. Our results suggest that the usefulness of conventional radiotracking data may be limited by potential biases and variability due to small samples. Investigators that use home range estimates in statistical tests should consider the
Jackson, Dan; Bowden, Jack
2016-09-07
Confidence intervals for the between study variance are useful in random-effects meta-analyses because they quantify the uncertainty in the corresponding point estimates. Methods for calculating these confidence intervals have been developed that are based on inverting hypothesis tests using generalised heterogeneity statistics. Whilst, under the random effects model, these new methods furnish confidence intervals with the correct coverage, the resulting intervals are usually very wide, making them uninformative. We discuss a simple strategy for obtaining 95 % confidence intervals for the between-study variance with a markedly reduced width, whilst retaining the nominal coverage probability. Specifically, we consider the possibility of using methods based on generalised heterogeneity statistics with unequal tail probabilities, where the tail probability used to compute the upper bound is greater than 2.5 %. This idea is assessed using four real examples and a variety of simulation studies. Supporting analytical results are also obtained. Our results provide evidence that using unequal tail probabilities can result in shorter 95 % confidence intervals for the between-study variance. We also show some further results for a real example that illustrates how shorter confidence intervals for the between-study variance can be useful when performing sensitivity analyses for the average effect, which is usually the parameter of primary interest. We conclude that using unequal tail probabilities when computing 95 % confidence intervals for the between-study variance, when using methods based on generalised heterogeneity statistics, can result in shorter confidence intervals. We suggest that those who find the case for using unequal tail probabilities convincing should use the '1-4 % split', where greater tail probability is allocated to the upper confidence bound. The 'width-optimal' interval that we present deserves further investigation.
Effect of sampling frequency on shoreline microbiology assessments.
Leecaster, M K; Weisberg, S B
2001-11-01
More than 80,000 shoreline bacteriological samples are collected annually in southern California to protect beachgoer health, but sampling frequency varies from daily to monthly among sampling sites. To assess the effectiveness of various sampling frequencies, we used five years of data from 24 Los Angeles area sites that have been monitored daily to simulate five alternative sampling strategies: five weekdays, five days per week including a weekend day, three days per week, weekly, and monthly. For each of these sampling strategies, we included in the simulation the local custom of adaptive sampling, in which a site is resampled the following day if bacterial concentrations exceed the State of California's beach water quality standards. We found that sampling five times per week resulted in observing about 80% of the events in which State standards were exceeded. This frequency dropped to 55%, 25%, and 5% for three times per week, weekly, and monthly sampling, respectively. Adaptive sampling was ineffective because nearly 70% of the water quality exceedences were single-day events, even at the most frequently contaminated sites. This high frequency of single-day events is of concern because the public is typically notified about water quality conditions 24-48 h after samples are collected, meaning that most warnings are out-of-date when they are issued.
Vandbakk, Kristine; Welde, Boye; Kruken, Andrea Hovstein; Baumgart, Julia; Ettema, Gertjan; Karlsen, Trine; Sandbakk, Øyvind
2017-01-01
This study compared the effects of adding upper-body sprint-intervals or continuous double poling endurance training to the normal training on maximal upper-body strength and endurance capacity in female cross-country skiers. In total, 17 female skiers (age: 18.1±0.8yr, body mass: 60±7 kg, maximal oxygen uptake (VO2max): 3.30±0.37 L.min-1) performed an 8-week training intervention. Here, either two weekly sessions of six to eight 30-s maximal upper-body double poling sprint-intervals (SIG, n = 8) or 45–75 min of continuous low-to-moderate intensity double poling on roller skis (CG, n = 9) were added to their training. Before and after the intervention, the participants were tested for physiological and kinematical responses during submaximal and maximal diagonal and double poling treadmill roller skiing. Additionally, we measured maximal upper-body strength (1RM) and average power at 40% 1RM in a poling-specific strength exercise. SIG improved absolute VO2max in diagonal skiing more than CG (8% vs 2%, p<0.05), and showed a tendency towards higher body-mass normalized VO2max (7% vs 2%, p = 0.07). Both groups had an overall improvement in double poling peak oxygen uptake (10% vs 6% for SIG and CG) (both p<0.01), but no group-difference was observed. SIG improved 1RM strength more than CG (18% vs 10%, p<0.05), while there was a tendency for difference in average power at 40% 1RM (20% vs 14%, p = 0.06). Oxygen cost and kinematics (cycle length and rate) in double poling and diagonal remained unchanged in both groups. In conclusion, our study demonstrates that adding upper-body sprint-interval training is more effective than continuous endurance training in improving upper-body maximal strength and VO2max. PMID:28241030
Schoenmakers, Patrick; Reed, Kate; Van Der Woude, Luc; Hettinga, Florentina J.
2016-01-01
Introduction: In lower body endurance training, quantities of both moderate intensity continuous training (MICT) and high intensity interval training (HIIT) can lead to an improved physiological capacity and performance. Limited research is available regarding the endurance and muscular capacity of the upper body, and how training contributes to improvements in performance capacity is still unknown. The aim of the current study was to evaluate the effects of HIIT and MICT on the physiological capacity and handcycling performance of able-bodied men in a well-controlled laboratory setting. Methods: Twenty four recreationally active men (22 ± 2 years; 1.84 ± 0.04 m; 79 ± 10 kg) were matched on incremental handcycling pre-test performance (peakPO) and then randomly assigned to HIIT, MICT, or a non-training control group (CON, 3 × n = 8). Participants in HIIT completed 14 interval training sessions, performing 4 × 4 min intervals at 85% heart rate reserve (%HRR), and seven continuous training sessions at 55 %HRR (every 2nd training session of the week). Participants in MICT performed 21 training sessions of 30 min at 55 %HRR. After the intervention, changes in peak oxygen uptake (peakVO2) and peak power output (peakPO) were compared within and between HIIT, MICT and CON. Results: The average external training load per training session did not differ between MICT and HIIT (p = 0.713). Improvements after HIIT in peakVO2 (22.2 ± 8.1%) and peakPO (47.1 ± 20.7%) were significantly larger compared with MICT and CON (p < 0.001). Improvements after MICT in peakVO2 (10.7 ± 12.9%) and peakPO (32.2 ± 8.1%) were higher compared to CON (p < 0.001). Higher improvement after HIIT occurred despite training 22% less time than MICT. No significant changes were found in CON. Discussion: As in lower body endurance sports, HIIT proved to be very effective in improving the physiological and performance capacity of upper body exercise. Whilst physiological capacity in both training
Schoenmakers, Patrick; Reed, Kate; Van Der Woude, Luc; Hettinga, Florentina J
2016-01-01
Introduction: In lower body endurance training, quantities of both moderate intensity continuous training (MICT) and high intensity interval training (HIIT) can lead to an improved physiological capacity and performance. Limited research is available regarding the endurance and muscular capacity of the upper body, and how training contributes to improvements in performance capacity is still unknown. The aim of the current study was to evaluate the effects of HIIT and MICT on the physiological capacity and handcycling performance of able-bodied men in a well-controlled laboratory setting. Methods: Twenty four recreationally active men (22 ± 2 years; 1.84 ± 0.04 m; 79 ± 10 kg) were matched on incremental handcycling pre-test performance (peakPO) and then randomly assigned to HIIT, MICT, or a non-training control group (CON, 3 × n = 8). Participants in HIIT completed 14 interval training sessions, performing 4 × 4 min intervals at 85% heart rate reserve (%HRR), and seven continuous training sessions at 55 %HRR (every 2nd training session of the week). Participants in MICT performed 21 training sessions of 30 min at 55 %HRR. After the intervention, changes in peak oxygen uptake (peakVO2) and peak power output (peakPO) were compared within and between HIIT, MICT and CON. Results: The average external training load per training session did not differ between MICT and HIIT (p = 0.713). Improvements after HIIT in peakVO2 (22.2 ± 8.1%) and peakPO (47.1 ± 20.7%) were significantly larger compared with MICT and CON (p < 0.001). Improvements after MICT in peakVO2 (10.7 ± 12.9%) and peakPO (32.2 ± 8.1%) were higher compared to CON (p < 0.001). Higher improvement after HIIT occurred despite training 22% less time than MICT. No significant changes were found in CON. Discussion: As in lower body endurance sports, HIIT proved to be very effective in improving the physiological and performance capacity of upper body exercise. Whilst physiological capacity in both training
Al-Dweri, Feras M O; Guirado, Damián; Lallena, Antonio M; Pedraza, Vicente
2004-07-07
In this work, a procedure, based on Monte Carlo techniques, to analyse the effect on the tumour control probability of the time interval between surgery and postoperative radiotherapy is presented. The approach includes the tumour growth as well as the survival of tumour cells undergoing fractionated radiotherapy. Both processes are described in terms of the binomial distribution. We have considered two different growth models, exponential and Gompertz, the parameters of which have been fixed to reproduce the clinical outcome corresponding to a retrospective study for patients with head and neck squamous cell carcinomas. In the cases analysed, we have not found significant differences between the results obtained for both growth models. The mean doubling times found for residual clonogens after surgery are less than 40 days. The rate of decrease in local control is around 0.09% per day of delay between surgery and radiotherapy and the corresponding time factor is about 0.11 Gy per day.
NASA Astrophysics Data System (ADS)
Al-Dweri, Feras M. O.; Guirado, Damián; Lallena, Antonio M.; Pedraza, Vicente
2004-07-01
In this work, a procedure, based on Monte Carlo techniques, to analyse the effect on the tumour control probability of the time interval between surgery and postoperative radiotherapy is presented. The approach includes the tumour growth as well as the survival of tumour cells undergoing fractionated radiotherapy. Both processes are described in terms of the binomial distribution. We have considered two different growth models, exponential and Gompertz, the parameters of which have been fixed to reproduce the clinical outcome corresponding to a retrospective study for patients with head and neck squamous cell carcinomas. In the cases analysed, we have not found significant differences between the results obtained for both growth models. The mean doubling times found for residual clonogens after surgery are less than 40 days. The rate of decrease in local control is around 0.09% per day of delay between surgery and radiotherapy and the corresponding time factor is about 0.11 Gy per day.
FALLAHI, Aliasghar; GAEINI, Abbasali; SHEKARFROUSH, Shahnaz; KHOSHBATEN, Ali
2015-01-01
Background: The aim of this study was to investigate the effects of High-Intensity Interval Training (HIIT) on nitric oxide metabolites (NO2−, NO3−) and myocardial infarct size after Ischemia/Reperfusion (I/R) injury in healthy male rats. Methods: A total of 44 Wistar rats were randomly divided into 4 groups including HIIT (n=8), HIIT + IR protocol (n=14), control (n=8), and control + IR (n=14). Each training session of HIIT consisted of 1 hour of exercise in three stages: 6-minute running at 50–60% VO2max for warm-up; 7 intervals of 7-minute running on treadmill with a slope of 5° to 20° (4 minutes with an intensity of 80–100% VO2max and 3 minutes at 50–60% VO2max); and 5-minute running at 50–60% VO2max for cool-down. The control group did not participate in any exercise program. Nitric Oxide (NO) and its metabolites were measured by using Griess reaction test. Results: The results showed that eight weeks of exercise training exerted a significantly increasing effect on nitrite (8.55 μmol per liter, equivalent to 34.79%), nitrate (62.02 μmol per liter, equivalent to 149.48%), and NOx (66 μmol per liter, equivalent to 98.11%) in the HIIT group compared with the control group. The results showed myocardial infract size (IS) was significantly smaller (23.2%, P<0.001) in the exercise training group compared with the control group. Conclusion: Incremental changes in NO-NO3−, NO2− axis are one of mechanisms through which HIIT program can protect the heart from I/R injury and decrease myocardial infarction. PMID:26587502
Watterson, James H; Desrosiers, Nathalie A
2011-04-15
The effect of dose-death interval and tissue distribution on the detection of meperidine in selected skeletal tissues was examined using a rapid microwave-assisted extraction (MAE) methodology. Rats (n=14) were dosed with 0 (n=2) or 30 mg/kg (n=12) meperidine (i.p.). Drug-positive rats were sacrificed with CO(2) after 20, 30, 90 and 150 min (n=3 per group). Heart blood was collected immediately after death. Tibiae were excised and frozen for further analysis. The remaining carcasses were allowed to decompose outside in secured cages to the point of complete skeletonization in a rural Northern Ontario location during the late summer months. Vertebrae and pelvi were collected for each animal. Tibial marrow was homogenized in 3 mL PB6 (phosphate buffer, 0.1M, pH 6). Fresh tibiae, and decomposed vertebrae and pelvi were cleaned in PB8.5 (phosphate buffer, 0.1M, pH 8.5) and sonicated to remove remaining soft tissue. Samples of dried, ground bone (0.5-1g) suspended in 2 mL PB6 were then irradiated in a domestic microwave oven (1100 W) at atmospheric pressure for 15 min. Samples of vertebral bone (1g) were also extracted by passive incubation in methanol (3 mL, 50°C, 72 h). All supernatants then underwent solid-phase extraction and analysis by GC/MS, using electron impact ionization in the Selected Ion Monitoring (SIM) mode. Mean GC/MS responses for each tissue type were negatively correlated with dose-death interval, with correlation coefficients ranging from -0.32 to -0.87. Analysis of variance showed dose-death interval to be a main effect (p<0.05) with respect to GC/MS response for blood, marrow, tibial epiphyses prepared by MAE, and vertebral bone prepared by passive extraction, but not for tibial diaphyses, pelvi or vertebrae prepared by MAE. Overall, MAE is advantageous as a rapid extraction tool for screening purposes in skeletal tissues, but assignment of significance to quantitative expressions of skeletal drug concentrations is complex and should be approached
Tracing selection effects in three non-probability samples.
Barendregt, Cas; van der Poel, Agnes; van de Mheen, Dike
2005-01-01
Snowball sampling and targeted sampling are widely applied techniques to recruit samples from hidden populations, such as problematic drug users. The disadvantage is that they yield non-probability samples which cannot be generalised to the population. Despite thorough preparatory mapping procedures, selection effects continue to occur. This paper proposes an interpretation frame that allows estimating the direction of selection bias after data collection. Critical examination of the recruitment procedure and comparison with statistical and non-statistical external data sources are the core features of the interpretation frame. Applying the interpretation frame increases insight into the reliability of the results and allows to estimate where selection bias may have occurred.
Mohammadhoseini, Elham; Safavi, Enayat; Seifi, Sepideh; Seifirad, Soroush; Firoozbakhsh, Shahram; Peiman, Soheil
2015-01-01
Background: Results of arterial blood gas analysis can be biased by pre-analytical factors, such as time interval before analysis, temperature during storage and syringe type. Objectives: To investigate the effects of samples storage temperature and time delay on blood gases, bicarbonate and PH results in human arterial blood samples. Patients and Methods: 2.5 mL arterial blood samples were drawn from 45 patients via an indwelling Intraarterial catheter. Each sample was divided into five equal samples and stored in multipurpose tuberculin plastic syringes. Blood gas analysis was performed on one of five samples as soon as possible. Four other samples were divided into two groups stored at 22°C and 0°C. Blood gas analyses were repeated at 30 and 60 minutes after sampling. Results: PaO2 of the samples stored at 0°C was increased significantly after 60 minutes (P = 0.007). The PaCO2 of the samples kept for 30 and 60 minutes at 22°C was significantly higher than primary result (P = 0.04, P < 0.001). In samples stored at 22°C, pH decreased significantly after 30 and 60 minutes (P = 0.017, P = 0.001). There were no significant differences in other results of samples stored at 0°C or 22°C after 30 or 60 minutes. Conclusions: In samples stored in plastic syringes, overestimation of PaO2 levels should be noted if samples cooled before analysis. In samples stored in plastic syringes, it is not necessary to store samples in iced water when analysis delayed up to one hour. PMID:26019892
The effectiveness of cooling conditions on temperature of canine EDTA whole blood samples
Sun, Xiaocun; Flatland, Bente
2016-01-01
Background Preanalytic factors such as time and temperature can have significant effects on laboratory test results. For example, ammonium concentration will increase 31% in blood samples stored at room temperature for 30 min before centrifugation. To reduce preanalytic error, blood samples may be placed in precooled tubes and chilled on ice or in ice water baths; however, the effectiveness of these modalities in cooling blood samples has not been formally evaluated. The purpose of this study was to evaluate the effectiveness of various cooling modalities on reducing temperature of EDTA whole blood samples. Methods Pooled samples of canine EDTA whole blood were divided into two aliquots. Saline was added to one aliquot to produce a packed cell volume (PCV) of 40% and to the second aliquot to produce a PCV of 20% (simulated anemia). Thirty samples from each aliquot were warmed to 37.7 °C and cooled in 2 ml allotments under one of three conditions: in ice, in ice after transfer to a precooled tube, or in an ice water bath. Temperature of each sample was recorded at one minute intervals for 15 min. Results Within treatment conditions, sample PCV had no significant effect on cooling. Cooling in ice water was significantly faster than cooling in ice only or transferring the sample to a precooled tube and cooling it on ice. Mean temperature of samples cooled in ice water was significantly lower at 15 min than mean temperatures of those cooled in ice, whether or not the tube was precooled. By 4 min, samples cooled in an ice water bath had reached mean temperatures less than 4 °C (refrigeration temperature), while samples cooled in other conditions remained above 4.0 °C for at least 11 min. For samples with a PCV of 40%, precooling the tube had no significant effect on rate of cooling on ice. For samples with a PCV of 20%, transfer to a precooled tube resulted in a significantly faster rate of cooling than direct placement of the warmed tube onto ice. Discussion Canine
The effectiveness of cooling conditions on temperature of canine EDTA whole blood samples.
Tobias, Karen M; Serrano, Leslie; Sun, Xiaocun; Flatland, Bente
2016-01-01
Preanalytic factors such as time and temperature can have significant effects on laboratory test results. For example, ammonium concentration will increase 31% in blood samples stored at room temperature for 30 min before centrifugation. To reduce preanalytic error, blood samples may be placed in precooled tubes and chilled on ice or in ice water baths; however, the effectiveness of these modalities in cooling blood samples has not been formally evaluated. The purpose of this study was to evaluate the effectiveness of various cooling modalities on reducing temperature of EDTA whole blood samples. Pooled samples of canine EDTA whole blood were divided into two aliquots. Saline was added to one aliquot to produce a packed cell volume (PCV) of 40% and to the second aliquot to produce a PCV of 20% (simulated anemia). Thirty samples from each aliquot were warmed to 37.7 °C and cooled in 2 ml allotments under one of three conditions: in ice, in ice after transfer to a precooled tube, or in an ice water bath. Temperature of each sample was recorded at one minute intervals for 15 min. Within treatment conditions, sample PCV had no significant effect on cooling. Cooling in ice water was significantly faster than cooling in ice only or transferring the sample to a precooled tube and cooling it on ice. Mean temperature of samples cooled in ice water was significantly lower at 15 min than mean temperatures of those cooled in ice, whether or not the tube was precooled. By 4 min, samples cooled in an ice water bath had reached mean temperatures less than 4 °C (refrigeration temperature), while samples cooled in other conditions remained above 4.0 °C for at least 11 min. For samples with a PCV of 40%, precooling the tube had no significant effect on rate of cooling on ice. For samples with a PCV of 20%, transfer to a precooled tube resulted in a significantly faster rate of cooling than direct placement of the warmed tube onto ice. Canine EDTA whole blood samples cool most
1990-05-30
intervals for MOE data. These screening intevals will be incorporated into the rule-based AI system under development. The AI system is being designed to cite...data values for selected MOE according to the study experience of senior analysts. The distribution of MOE output data may be considered to be bounded ...regarding the concept of screening intervals primarily surfaced the notion of confidence intervals for estimation o population parameters using
Sloth, M; Sloth, D; Overgaard, K; Dalgas, U
2013-12-01
Recently, several studies have examined whether low-volume sprint interval training (SIT) may improve aerobic and metabolic function. The objective of this study was to systematically review the existing literature regarding the aerobic and metabolic effects of SIT in healthy sedentary or recreationally active adults. A systematic literature search was performed (Bibliotek.dk, SPORTDiscus, Embase, PEDro, SveMed+, and Pubmed). Meta-analytical procedures were applied evaluating effects on maximal oxygen consumption (VO2max). Nineteen unique studies [four randomized controlled trials (RCTs), nine matched-controlled trials and six noncontrolled studies] were identified, evaluating SIT interventions lasting 2-8 weeks. Strong evidence support improvements of aerobic exercise performance and VO2max following SIT. A meta-analysis across 13 studies evaluating effects of SIT on VO2max showed a weighted mean effects size of g = 0.63 95% CI (0.39; 0.87) and VO2max increases of 4.2-13.4%. Solid evidence support peripheral adaptations known to increase the oxidative potential of the muscle following SIT, whereas evidence regarding central adaptations was limited and equivocal. Some evidence indicated changes in substrate oxidation at rest and during exercise as well as improved glycemic control and insulin sensitivity following SIT. In conclusion, strong evidence support improvement of aerobic exercise performance and VO2max following SIT, which coincides with peripheral muscular adaptations. Future RCTs on long-term SIT and underlying mechanisms are warranted.
Effects of sample homogenization on solid phase sediment toxicity
Anderson, B.S.; Hunt, J.W.; Newman, J.W.; Tjeerdema, R.S.; Fairey, W.R.; Stephenson, M.D.; Puckett, H.M.; Taberski, K.M.
1995-12-31
Sediment toxicity is typically assessed using homogenized surficial sediment samples. It has been recognized that homogenization alters sediment integrity and may result in changes in chemical bioavailability through oxidation-reduction or other chemical processes. In this study, intact (unhomogenized) sediment cores were taken from a Van Veen grab sampler and tested concurrently with sediment homogenate from the same sample in order to investigate the effect of homogenization on toxicity. Two different solid-phase toxicity test protocols were used for these comparisons. Results of amphipod exposures to samples from San Francisco Bay indicated minimal difference between intact and homogenized samples. Mean amphipod survival in intact cores relative to homogenates was similar at two contaminated sites. Mean survival was 34 and 33% in intact and homogenized samples, respectively, at Castro Cove. Mean survival was 41% and 57%, respectively, in intact and homogenized samples from Islais Creek. Studies using the sea urchin development protocol, modified for testing at the sediment/water interface, indicated considerably more toxicity in intact samples relative to homogenized samples from San Diego Bay. Measures of metal flux into the overlying water demonstrated greater flux of metals from the intact samples. Zinc flux was five times greater, and copper flux was twice as great in some intact samples relative to homogenates. Future experiments will compa