Pink Noise in Rowing Ergometer Performance and the Role of Skill Level

The aim of this study was to examine (1) the temporal structures of variation in rowers’ (natural) ergometer strokes to make inferences about the underlying motor organization, and (2) the relation between these temporal structures and skill level. Four high-skilled and five lower-skilled rowers completed 550 strokes on a rowing ergometer. Detrended Fluctuation Analysis was used to quantify the temporal structure of the intervals between force peaks. Results showed that the temporal structure differed from random, and revealed prominent patterns of pink noise for each rower. Furthermore, the high-skilled rowers demonstrated more pink noise than the lower-skilled rowers. The presence of pink noise suggests that rowing performance emerges from the coordination among interacting component processes across multiple time scales. The difference in noise pattern between high-skilled and lower-skilled athletes indicates that the complexity of athletes’ motor organization is a potential key characteristic of elite performance.

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Spatial Motion of a String Subjected to Two Harmonic Excitations With Different Frequencies

Volume 1: 20th Biennial Conference on Mechanical Vibration and Noise, Parts A, B, and C ◽

10.1115/detc2005-85144 ◽

2005 ◽

Author(s):

Keisuke Kamiya ◽

Kimihiko Yasuda

Keyword(s):

Theoretical Analysis ◽

Time Scales ◽

Natural Frequencies ◽

Multiple Time Scales ◽

Multiple Time ◽

Combination Resonance ◽

Spatial Motion ◽

Harmonic Excitations ◽

The Difference

This paper studies spatial motion of a stretched string subjected to two harmonic excitations with different frequencies. Two cases are considered, one in which both excitations are in a plane, and one in which they are perpendicular to each other. First, theoretical analysis by the method of multiple time scales is conducted. It is found that in the former case sub-combination resonance and summed-and-differential combination resonance of whirling type can occur, and in the latter case sub-combination resonances parallel and perpendicular to the excitations and of whirling type can occur. Then, experiment is conducted. In the experiment, it was confirmed that the same types of motions as those predicted in the theoretical analysis occured. In addition, it was found that for the case in which the excitations are in a plane the response is sensitive to the difference between the natural frequencies in the two perpendicular directions. Finally, effect of the difference between the natural frequencies is studied.

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Different Circadian Rest-Active Rhythms in Kleine-Levin Syndrome: A prospective and case-control study

SLEEP ◽

10.1093/sleep/zsab096 ◽

2021 ◽

Author(s):

Chen Lin ◽

Wei-Chih Chin ◽

Yu-Shu Huang ◽

Kuo-Chung Chu ◽

Teresa Paiva ◽

...

Keyword(s):

Circadian Rhythm ◽

Young Patients ◽

Recovery Phase ◽

Multiple Time Scales ◽

Fluctuation Analysis ◽

Multiple Time ◽

Temporal Correlations ◽

Significant Difference ◽

Attack Phase ◽

Physiological Markers

Abstract Study objectives Kleine-Levin-syndrome (KLS) is a rare recurrent hypersomnia. Our study aimed at monitoring the movements of patients with KLS using actigraphy and evaluating their circadian rhythm. Methods Twenty young patients with KLS and 14 age-matched controls were recruited. Each individual wore an actigraphy for more than 6 months to monitor at least two attacks. Controls kept wearing the device for at least 7 days. The activity counts were averaged in hourly basis and the day-to-night amplitude was quantified by the differences of the averaged activity counts during daytime and nighttime. The hourly activities of different days were aligned and averaged to construct the circadian profile. Parametric and nonparametric estimation of circadian rhythm was calculated. We applied detrended fluctuation analysis to evaluate the temporal correlations beneath the activity fluctuations at multiple time scales. Results Circadian rhythm in asymptomatic period showed no significant difference compared to the controls. During hypersomnia attack, the amplitude of the circadian rest-active rhythms drastically decreased and decreased inter-daily stability (IS) was found, as well as significant decreased M10 and short-time fractal correlation (α1). Drastically decreased mean and standard deviation of activity were noted, compared to the pre-attack phase and recovery phase.α1 and M10 increased during the late attack phase, and overcompensated IS was noted in the recovery phase. Conclusions This study confirmed that circadian rest-active rhythms was affected when KLS hypersomnia attack. Several parameters including M10, IS and α1 may be physiological markers of KLS, which can help to predict the end of hypersomnia episodes.

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Nonlinear Kelvin–Helmholtz instability in hydromagnetics

Journal of Plasma Physics ◽

10.1017/s0022377800009909 ◽

1979 ◽

Vol 22 (1) ◽

pp. 27-39 ◽

Cited By ~ 4

Author(s):

H. Nagano

Keyword(s):

Growth Rate ◽

Time Scales ◽

Linear Instability ◽

The Other ◽

Multiple Time Scales ◽

Multiple Time ◽

Helmholtz Instability ◽

Wavenumber Domain ◽

The Difference

Nonlinear Kelvin–Helmholtz instability for an incompressible plasma under the influence of gravity is investigated theoretically, using the method of multiple time-scales. The effect of nonlinearity is to reduce the growth rate for the linear instability and to narrow the unstable wavenumber domain. There are two cases, in one of which the effect is strong and in the other slight. The difference between these cases is studied.

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Temporal structure in sensorimotor variability: a stable trait, but what for?

10.1101/817916 ◽

2019 ◽

Author(s):

Marlou Nadine Perquin ◽

Aline Bompas

Keyword(s):

Individual Differences ◽

Task Performance ◽

Human Performance ◽

Temporal Structure ◽

Power Spectra ◽

Data Series ◽

Fluctuation Analysis ◽

Individual Traits ◽

Temporal Structures ◽

Thought Probes

AbstractHuman performance shows substantial endogenous variability over time, and this variability is a robust marker of individual differences. Variability is not fully random, but often exhibits temporal dependencies. However, their measurement and interpretation come with several controversies, and their potential benefit for studying individual differences remains unclear. Two recent studies have linked individual differences in temporal structures to task performance on the same data, but with contrasting results. Here we use the metronome task, requiring participants to press a button in synchrony with a tone, widely used to study sensorimotor variability. We first investigate the intra-individual repeatability of the most common measures of temporal structures. Secondly, we examine inter-individual correlates of these measures with: 1) task performance assessed from the same data series, 2) meta-cognitive ratings of on-taskness from thought probes occasionally presented throughout the task, and 3) self-assessed traits commonly assumed to relate to attention or sensorimotor control (ADHD tendencies, mind wandering, and impulsivity). Autocorrelation at lag 1 and Power Spectra Density slope showed high repeatability and good correlations with task performance. Detrended Fluctuation Analysis slope showed the same pattern, but less reliably. The long-term component (d) of the ARFIMA(1,d,1) model shows poor repeatability and no correlation to performance. None of these measures showed external validity when correlated to either mean subjective attentional state or self-assessed traits between participants. In sum, some measures of serial dependencies may be stable individual traits, but their usefulness to study individual differences in other constructs typically associated with variability in performance remains elusive.

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At which time scale does the complementary principle perform best on evaporation estimation?

10.5194/hess-2020-379 ◽

2020 ◽

Author(s):

Liming Wang ◽

Songjun Han ◽

Fuqiang Tian

Keyword(s):

Uncertainty Analysis ◽

Eddy Covariance ◽

Time Scales ◽

Time Scale ◽

Multiple Time Scales ◽

Multiple Time ◽

Energy Correction ◽

Independent Variable ◽

The Difference ◽

Annual Time

Abstract. The complementary principle has been widely used to estimate evaporation under different conditions. However, it remains unclear that at which time scale the complementary principle performs best. In this study, evaporation estimation was assessed over 88 eddy covariance (EC) monitoring sites at multiple time scales (daily, weekly, monthly, and yearly) by using the sigmoid and polynomial generalized complementary functions. The results indicate that the generalized complementary functions exhibit the highest skill in estimating evaporation at the monthly scale. The uncertainty analysis shows that this conclusion is not affected by ecosystem types nor energy correction methods. Through comparisons at multiple time scales, we found that the slight difference between the two generalized complementary functions only exists when the independent variable (x) in the functions approaches 1. The difference results in different performance of the two models at daily and weekly scales. However, such difference vanishes at monthly and annual time scales as few high x occurrences. This study demonstrates the applicability of the generalized complementary functions across multiple time scales and provides a reference for choosing the suitable timestep for evaporation estimation in relevant studies.

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SOME REMARKS ON THE MULTIPLE TIME SCALES OF DIFFUSION IN MINERALS AND MELTS

10.1130/abs/2018am-323387 ◽

2018 ◽

Author(s):

Yan Liang ◽

◽

Daniele J. Cherniak ◽

Chenguang Sun

Keyword(s):

Time Scales ◽

Multiple Time Scales ◽

Multiple Time

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Robust optimal scheduling of integrated energy systems based on hybrid energy storage and multiple time scales

2020 IEEE Sustainable Power and Energy Conference (iSPEC) ◽

10.1109/ispec50848.2020.9351230 ◽

2020 ◽

Author(s):

Mingfang Lu ◽

Xianshan Li ◽

Fei Li

Keyword(s):

Energy Storage ◽

Time Scales ◽

Energy Systems ◽

Optimal Scheduling ◽

Multiple Time Scales ◽

Multiple Time ◽

Hybrid Energy ◽

Hybrid Energy Storage ◽

Integrated Energy Systems

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Odor response adaptation in Drosophila—a continuous individualization process

Cell and Tissue Research ◽

10.1007/s00441-020-03384-6 ◽

2021 ◽

Vol 383 (1) ◽

pp. 143-148

Author(s):

Shadi Jafari ◽

Mattias Alenius

Keyword(s):

Sensory Neurons ◽

Olfactory System ◽

Multiple Time Scales ◽

Multiple Time ◽

Olfactory Perception ◽

Adaptation Mechanisms ◽

Metabolic States ◽

The Central Nervous System ◽

Olfactory Adaptation ◽

Central Adaptation

AbstractOlfactory perception is very individualized in humans and also in Drosophila. The process that individualize olfaction is adaptation that across multiple time scales and mechanisms shape perception and olfactory-guided behaviors. Olfactory adaptation occurs both in the central nervous system and in the periphery. Central adaptation occurs at the level of the circuits that process olfactory inputs from the periphery where it can integrate inputs from other senses, metabolic states, and stress. We will here focus on the periphery and how the fast, slow, and persistent (lifelong) adaptation mechanisms in the olfactory sensory neurons individualize the Drosophila olfactory system.

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Are We Doing ‘Systems’ Research? An Assessment of Methods for Climate Change Adaptation to Hydrohazards in a Complex World

Sustainability ◽

10.3390/su11041163 ◽

2019 ◽

Vol 11 (4) ◽

pp. 1163 ◽

Cited By ~ 4

Author(s):

Melissa Bedinger ◽

Lindsay Beevers ◽

Lila Collet ◽

Annie Visser

Keyword(s):

Climate Change ◽

Human Nature ◽

Climate Change Adaptation ◽

Time Scales ◽

Spatial Scales ◽

Local Context ◽

Multiple Time Scales ◽

Future Research ◽

Multiple Time ◽

Systems Research

Climate change is a product of the Anthropocene, and the human–nature system in which we live. Effective climate change adaptation requires that we acknowledge this complexity. Theoretical literature on sustainability transitions has highlighted this and called for deeper acknowledgment of systems complexity in our research practices. Are we heeding these calls for ‘systems’ research? We used hydrohazards (floods and droughts) as an example research area to explore this question. We first distilled existing challenges for complex human–nature systems into six central concepts: Uncertainty, multiple spatial scales, multiple time scales, multimethod approaches, human–nature dimensions, and interactions. We then performed a systematic assessment of 737 articles to examine patterns in what methods are used and how these cover the complexity concepts. In general, results showed that many papers do not reference any of the complexity concepts, and no existing approach addresses all six. We used the detailed results to guide advancement from theoretical calls for action to specific next steps. Future research priorities include the development of methods for consideration of multiple hazards; for the study of interactions, particularly in linking the short- to medium-term time scales; to reduce data-intensivity; and to better integrate bottom–up and top–down approaches in a way that connects local context with higher-level decision-making. Overall this paper serves to build a shared conceptualisation of human–nature system complexity, map current practice, and navigate a complexity-smart trajectory for future research.

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