Main Effect Of Duration Research Articles

Effect of different paces of suryanamaskar on leg strength of school students

The aim of this study was to see the effect of suryanamaskar practice with different paces on leg strength of school students. Study had three objectives, first see the interaction effect of training duration and groups, second the main effect of duration, and third the main effect of groups. Within between mixed design was used. Three experimental intact groups were created Pace 1 group, Pace 2 group and Pace 4 group, each group had 15 subjects with age range between 15-17 years. Pace 1 group practiced one round (12 steps) of suryanamaskar in 1 minute, Pace 2 group in 2 minutes and Pace 4 group in 4 minutes. The maximum strength of the legs was measured by the leg dynamometer test. Total 12 weeks training was given in which three observations were taken before the training (pre-test), after 6 weeks (mid-test) and after 12 weeks (post-test). 3 X 3 mixed factorial ANOVA was used and level of significance was set at 0.05. Result showed that practice of Suryanamaskar for 6 weeks and 12 weeks were sufficient to bring out significant improvement on leg strength (main effect of training duration).

Global loudness of rising- and falling-intensity tones: How temporal profile characteristics shape overall judgments

The mechanisms underlying global loudness judgments of rising- or falling-intensity tones were further investigated in two magnitude estimation experiments. By manipulating the temporal characteristics of such stimuli, it was examined whether judgments could be accounted for by an integration of their loudest portion over a certain temporal window associated to a "decay mechanism" downsizing this integration over time for falling ramps. In experiment 1, 1-kHz intensity-ramps were stretched in time between 1 and 16 s keeping their dynamics (difference between maximum and minimum levels) unchanged. While global loudness of rising tones increased up to 6 s, evaluations of falling tones increased at a weaker rate and slightly decayed between 6 and 16 s, resulting in significant differences between the two patterns. In experiment 2, ramps were stretched in time between 2 and 12 s keeping their slopes (rate of change in dB/s) unchanged. In this context, the main effect of duration became non-significant and the interaction between the two profiles remained, although the decay of falling tones was not significant. These results qualitatively support the view that the global loudness computation of intensity-ramps involves an integration of their loudest portions; the presence of a decay mechanism could, however, not be attested.

Head rotational acceleration characteristics influence behavioral and diffusion tensor imaging outcomes following concussion.

A majority of traumatic brain injuries (TBI) in motor vehicle crashes and sporting environments are mild and caused by high-rate acceleration of the head. For injuries caused by rotational acceleration, both magnitude and duration of the acceleration pulse were shown to influence injury outcomes. This study incorporated a unique rodent model of rotational acceleration-induced mild TBI (mTBI) to quantify independent effects of magnitude and duration on behavioral and neuroimaging outcomes. Ninety-two Sprague-Dawley rats were exposed to head rotational acceleration at peak magnitudes of 214 or 350krad/s(2) and acceleration pulse durations of 1.6 or 3.4ms in a full factorial design. Rats underwent a series of behavioral tests including the Composite Neuroscore (CN), Elevated Plus Maze (EPM), and Morris Water Maze (MWM). Ex vivo diffusion tensor imaging (DTI) of the fixed brains was conducted to assess the effects of rotational injury on brain microstructure as revealed by the parameter fractional anisotropy (FA). While the injury did not cause significant locomotor or cognitive deficits measured with the CN and MWM, respectively, a main effect of duration was consistently observed for the EPM. Increased duration caused significantly greater activity and exploratory behaviors measured as open arm time and number of arm changes. DTI demonstrated significant effects of both magnitude and duration, with the FA of the amygdala related to both the magnitude and duration. Increased duration also caused FA changes at the interface of gray and white matter. Collectively, the findings demonstrate that the consequences of rotational acceleration mTBI were more closelyassociated with duration of the rotational acceleration impulse, which is often neglected as an independent factor, and highlight the need for animal models of TBI with strong biomechanical foundations to associate behavioral outcomes with brain microstructure.

Judgments of sound volume: effects of signal duration, level, and interaural characteristics on the perceived extensity of broadband noise.

While auditory stimuli are often described in terms of their apparent extensity, such descriptions have usually not been collected systematically. Moreover, the few deliberate attempts to evaluate image size have rarely gone beyond the classic parameters of stimulus frequency and intensity. In the present study a direct magnitude estimation procedure was employed. Seventeen subjects numerically estimated the apparent size of images produced by broadband noise stimuli. Under earphone listening conditions, signals were presented either dichotically (uncorrelated noise), diotically (correlated noise), or monaurally (noise led to a single earphone). The signals in each of these modes varied in duration (100, 300, 1000, and 3000 msec) and intensity level (60, 75, and 90 dB A weighted). Size estimates were plotted as power functions and analyzed with a repeated measures design analysis of variance. Consistent with previous research, the main effects of duration and intensity were both highly significant (p less than 0.001). In addition, a highly significant effect for mode of presentation was found (p less than 0.001). Across conditions, dichotic stimulation produced the largest images and monaural stimulation the smallest (about half the size of the diotic images). This last result is the first quantification of previous anecdotal observations. General implications of these results were discussed.