Nonrandom Fluctuations Research Articles

Effect of Month of Birth on Mean Birth Length in Austrian Newborns Born Between 1984 and 2021.

The length of newborns shows seasonal fluctuations, but the patterns of these fluctuations vary greatly. This study analyses the fluctuation in birth length by birth month and temporal changes in Austrian newborns from the 1984 to 2021 birth cohorts. A total of 2 317 927 singleton-term births between 1984 and 2021 in Austria were included in this retrospective population-based cohort study. A strict inclusion criterion was the Austrian citizenship of the mother. The effect of month of birth (MOB) on birth length was estimated using a multivariable linear model adjusting for maternal educational level, newborn sex, gestational age, year of birth (YOB) of the newborn, and parity of the mother. Newborn length varied by MOB, but there was also a temporal trend. In the birth cohorts up to 2004, the longest newborns were born in February, while from 2008 onward, the longest birth lengths were observed in the summer months. In this Austrian population-based sample, birth length shows nonrandom fluctuations by birth month. These patterns, however, varied considerably over time.

Scaling and Complexity of Stress Fluctuations Associated with Smooth and Jerky Flow in FeCoNiTiAl High-Entropy Alloy

Recent observations of jerky flow in high-entropy alloys (HEA) revealed a high role of self-organization of dislocations in their plasticity. The present work reports the first results of the investigation of stress fluctuations during plastic deformation of an FeCoNiTiAl alloy, examined in a wide temperature range covering both smooth and jerky flow. These fluctuations, which accompany the overall deformation behavior representing an essentially slower stress evolution controlled by the work hardening, were processed using complementary approaches comprising Fourier spectral analysis, refined composite multiscale entropy, and multifractal formalisms. The joint analysis at distinct scales testified that even a macroscopically smooth plastic flow is accompanied by nonrandom fluctuations, disclosing the self-organized dynamics of dislocations. Qualitative changes in such a fine-scale “noise” were found with varying temperature. The observed diversity is significant for understanding the relationships between different scales of plasticity of HEAs and crystal materials in general.

Open-ended movements structure sensorimotor information in early human development

Human behaviors, with whole-body coordination, involve large-scale sensorimotor interaction. Spontaneous bodily movements in the early developmental stage potentially lead toward acquisition of such coordinated behavior. These movements presumably contribute to the structuration of sensorimotor interaction, providing specific regularities in bidirectional information among muscle activities and proprioception. Whether and how spontaneous movements, despite being task-free, structure and organize sensorimotor interactions in the entire body during early development remain unknown. Herein, to address these issues, we gained insights into the structuration process of the sensorimotor interaction in neonates and 3-mo-old infants. By combining detailed motion capture and musculoskeletal simulation, sensorimotor information flows among muscle activities and proprioception throughout the body were obtained. Subsequently, we extracted spatial modules and temporal state in sensorimotor information flows. Our approach demonstrated that early spontaneous movements elicited body-dependent sensorimotor modules, revealing age-related changes in them, depending on the combination or direction. The sensorimotor interactions also displayed temporal non-random fluctuations analogous to those seen in spontaneous activities in the cerebral cortex and spinal cord. Furthermore, we found recurring state sequence patterns across multiple participants, characterized by a substantial increase in infants compared to the patterns in neonates. Therefore, early spontaneous movements induce the spatiotemporal structuration in sensorimotor interactions and subsequent developmental changes. These results implicated that early open-ended movements, emerging from a certain neural substrate, regulate the sensorimotor interactions through embodiment and contribute to subsequent coordinated behaviors. Our findings also provide a conceptual linkage between early spontaneous movements and spontaneous neuronal activity in terms of spatiotemporal characteristics.

Changes in torque complexity and maximal torque after a fatiguing exercise protocol

ABSTRACT Torque outputs exhibit non-random fluctuations in their temporal structure, i.e., complexity. Fatigue has been shown to alter this structure. The torque outputs typically become more regular, resulting in decreased adaptability. Importantly, torque complexity was shown a different recovery pattern after fatigue compared to maximal torque. However, it remains to be understood if these uncoupled patterns of recovery are muscle dependent. In addition, it also remains to be investigated if changes in maximal torque and complexity are correlated. This study investigated (i) the effects of a fatiguing protocol on the complexity and maximal torque from plantar flexors and (ii) the relationship between changes in these two outputs. Ten participants visited the laboratory, and measures were taken at baseline, immediately after, 1 h after and 24 h after the fatiguing protocol. Maximum voluntary contraction, isometric contractions at 30% of maximum and pain pressure threshold were collected. Both legs were assessed, but only one was given the fatiguing protocol. Two-way ANOVAs and correlations were conducted. The fatiguing protocol decreased torque complexity (~35%) and maximal torque (~20%), and they exhibited uncoupled patterns of recovery. Moreover, the correlation analysis showed no correlation between changes in these parameters. These findings support that these parameters are independent of each other.

DNA coding and Gödel numbering

We consider a DNA strand as a mathematical statement. Inspired by the work of Kurt Gödel, we attach to each DNA strand a Gödel’s number, a product of prime numbers raised to appropriate powers. To each DNA chain corresponds a single Gödel’s number G, and inversely given a Gödel’s number G, we can specify the DNA chain it stands for. Next, considering a single DNA strand composed of N bases, we study the statistical distribution of g, the logarithm of G. Our assumption is that the choice of the mth term is random and with equal probability for the four possible outcomes. The ‘experiment’, to some extent, is similar to throwing N times a four-faces die. Through the moment generating function we obtain the discrete and then the continuum distribution of g. There is an excellent agreement between our formalism and simulated data. At the end we compare our formalism to actual data, to specify the presence of non-random fluctuations.

Computational Capacity of a Cell Exhibiting Non-random Fluctuation

Computational Capacity of a Cell Exhibiting Non-random Fluctuation

Interaction between the progression of Alzheimer's disease and fractal degradation

Many outputs from healthy neurophysiological systems including motor activity display nonrandom fluctuations with fractal scaling behavior as characterized by similar temporal fluctuation patterns across a range of time scales. Degraded fractal regulation predicts adverse consequences including Alzheimer's dementia. We examined longitudinal changes in the scaling behavior of motor activity fluctuations during the progression of Alzheimer's disease (AD) in 1068 participants in the Rush Memory and Aging Project. Motor activity of up to 10 days was recorded annually for up to 13 years. Cognitive assessments and clinical diagnoses were administered annually in the same participants. We found that fractal regulation gradually degraded over time (p < 0.0001) even during the stage with no cognitive impairment. The degradation rate was more than doubled after the diagnosis of mild cognitive impairment and more than doubled further after the diagnosis of Alzheimer's dementia (p's ≤ 0.0005). Besides, the longitudinal degradation of fractal regulation significantly correlated with the decline in cognitive performance throughout the progression from no cognitive impairment to mild cognitive impairment, and to AD (p < 0.001). All effects remained the same in subsequent sensitivity analyses that included only 255 decedents with autopsy-confirmed Alzheimer's pathology. These results indicate that the progression of AD accelerates fractal degradation and that fractal degradation may be an integral part of the process of AD.

Divergence of non-random fluctuation in First Passage Percolation

We study the non-random fluctuation in first passage percolation and show that it diverges. We also prove the divergence of non-random shape fluctuation, which was predicted in [Yu Zhang. The divergence of fluctuations for shape in first passage percolation. Probab. Theory. Related. Fields. 136(2) 298–320, 2006].

Long-range correlations and complex regulation of pacing in long-distance road racing.

To analyze time-domain, spectral, and fractal properties of speed regulation during half-marathon racing. In 21 male experienced runners, high-resolution data on speed (V), stride frequency (SF), and stride length (SL) were assessed during half-marathon competition (21,098 m). Performance times, time- and frequency-domain variability, spectral-scaling exponent (beta), and fractal dimension (FD) of V, SF, and SL were analyzed. V of 3.65 ± 0.41 m/s, SF of 1.41 ± 0.05 Hz, and SL of 2.58 ± 0.25 m occurred with higher (P < .05) individual variability in V and SL than in SF. Beta and FD were always 1.04-1.88 and 1.56-1.99, respectively. Beta and FD differed (P < .05) in SF and SL compared with V and were correlated in V and SL (r = .91, P < .05). Spectral peaks of V, SF, and SL occurred at wavelengths of 3-35 min, and those of V and SL were interrelated (r = .56, P < .05). Mean SF and mean SL were significantly correlated with performance (r = .59 and r = .95, P < .05). SL accounted for 84% ± 6% and SF for 16% ± 6% of speed variability. The observed nonrandom fluctuations in V, SF, and SL correspond to nonstationary fractional Brownian motion with inherent long-range correlations. This indicates a similar complex regulation process in experienced runners that is primarily mediated via SL.

Influence of Climate on Emergency Department Visits for Syncope: Role of Air Temperature Variability

BackgroundSyncope is a clinical event characterized by a transient loss of consciousness, estimated to affect 6.2/1000 person-years, resulting in remarkable health care and social costs. Human pathophysiology suggests that heat may promote syncope during standing. We tested the hypothesis that the increase of air temperatures from January to July would be accompanied by an increased rate of syncope resulting in a higher frequency of Emergency Department (ED) visits. We also evaluated the role of maximal temperature variability in affecting ED visits for syncope.Methodology/Principal FindingsWe included 770 of 2775 consecutive subjects who were seen for syncope at four EDs between January and July 2004. This period was subdivided into three epochs of similar length: 23 January–31 March, 1 April–31 May and 1 June–31 July. Spectral techniques were used to analyze oscillatory components of day by day maximal temperature and syncope variability and assess their linear relationship.There was no correlation between daily maximum temperatures and number of syncope. ED visits for syncope were lower in June and July when maximal temperature variability declined although the maximal temperatures themselves were higher. Frequency analysis of day by day maximal temperature variability showed a major non-random fluctuation characterized by a ∼23-day period and two minor oscillations with ∼3- and ∼7-day periods. This latter oscillation was correlated with a similar ∼7-day fluctuation in ED visits for syncope.Conclusions/SignificanceWe conclude that ED visits for syncope were not predicted by daily maximal temperature but were associated with increased temperature variability. A ∼7-day rhythm characterized both maximal temperatures and ED visits for syncope variability suggesting that climate changes may have a significant effect on the mode of syncope occurrence.

On the importance of body size in the colonisation of ephemeral resource patches by vagile consumers

A study on the colonisation of leaf detritus patches by vagile macroinvertebrates in a brackish lagoon is presented in the framework of a conceptual model where a body size-related constraint on patch use behaviour is explicitly considered. Abundance patterns of dominant macroinvertebrate taxa were characterised by short-term, non-random fluctuations, showing significant site-dependent variations. Yet, a site-independent covariation was observed between patterns’ fractal dimension and the average body mass of each taxon, indicating that, while the temporal scales characterising the colonisation patterns may be highly species-specific, cross-species generalisations are possible based on body size. The generality of these results was supported by literature data on temporal patterns of carcass colonisation by bathyal fish. The importance of size-related mechanisms in regulating the aggregation of vagile consumers on resource patches and, ultimately, their coexistence at both an inter- and intra-specific level, is discussed.

Nonlinear scaling analysis of glucose metabolism in normal and cancer cells

Cancer progression is commonly accompanied by an altered glucose metabolism. In general, spatially resolved imaging of glucose metabolism and its subtle alterations might provide valuable diagnostic information in vivo. A classical example is positron emission tomography that exploits this feature in obtaining preferential accumulation of fluorescent analog of glucose in tumors, thereby achieving an imaging contrast. We report a novel scaling analysis of glucose metabolism in mammary epithelial (NMuMG) cells by detrended fluctuation analysis of Cerulean (cyan fluorescent protein variant) fluorescence. Fluorescence fluctuations of Cerulean are reasoned to be indicative of dynamic pH changes associated with glucose metabolism. Normal parental cells and the spontaneously transformed (cancerous) NMuMG cells displayed robust scaling exponent that reflects nonrandom fluctuations in Cerulean fluorescence. Acute dependence of cancer cells on glycolysis as compared with normal cells is exploited to yield a statistically significant difference in scaling exponent, thereby providing discrimination between normal and cancer cells in vitro. By careful design of experiments in vivo, the proposed scaling approach might even have diagnostic potential for early detection of cancer lesions in small animal models.

The genetic diversity of UK, US and Australian cultivars of Triticum aestivum measured by DArT markers and considered by genome

The genetic diversity of UK, US and Australian wheat varieties over the period of modern plant breeding is estimated using diversity array technology markers. Diversity is assessed by both genetic distance between varieties, by AMOVA and as the volumes of multi-dimensional convex hulls estimated from principal co-ordinate analysis. At the whole genome level the three populations are genetically distinct; this is also true of the B genome. However, the US and Australian D genomes are found to occupy the same region of diversity space and the A genomes for these countries are partially overlapping. The use of high-density genotyping with a common marker set allows an unprecedented direct comparison between the diversities of the national populations, between individual genomes and the fluctuation of diversity over time. The highest genetic diversity amongst varieties is reported in the Australian population followed by the US, which in turn is more diverse than the UK. However the average diversity of loci is higher in the US set than in the Australian. Non-random fluctuations in genetic diversity over time are observed.

Non-random fluctuations in power output during self-paced exercise

Objectives: To analyse the power output measured during a self-paced 20-km cycling time trial, during which power output was free to vary, in order to assess the level and characteristics...

Event-by-event average pT fluctuations in GeV Au + Au and p + p collisions in PHENIX: measurements and jet contribution simulations

Small, but significant non-random fluctuations in event-by-event average pT have been observed in Au+Au collisions at GeV by the PHENIX Collaboration. These are consistent with being caused by correlations due to jets at large pT, where the measured suppression must be included to reproduce the centrality dependence of the non-random fluctuations.

Non-random fluctuations and multi-scale dynamics regulation of human activity

We investigate if known extrinsic and intrinsic factors fully account for the complex features observed in recordings of human activity as measured from forearm motion in subjects undergoing their regular daily routine. We demonstrate that the apparently random forearm motion possesses dynamic patterns characterized by robust scale-invariant and nonlinear features. These patterns remain stable from one subject to another and are unaffected by changes in the average activity level that occur within individual subjects throughout the day and on different days of the week, since they persist during daily routine and when the same subjects undergo time-isolation laboratory experiments designed to account for the circadian phase and to control the known extrinsic factors. Further, by modeling the scheduled events imposed throughout the laboratory protocols, we demonstrate that they cannot account for the observed scaling patterns in activity fluctuations. We attribute these patterns to a previously unrecognized intrinsic nonlinear multi-scale control mechanism of human activity that is independent of known extrinsic factors such as random and scheduled events, as well as the known intrinsic factors which possess a single characteristic time scale such as circadian and ultradian rhythms.

Event-by-event fluctuations in meanpTand meaneTinsNN=130 GeVAu+Au collisions

Distributions of event-by-event fluctuations of the mean transverse momentum and mean transverse energy near mid-rapidity have been measured in Au+Au collisions at roots(NN)=130 GeV at the Relativistic Heavy-Ion Collider. By comparing the distributions to what is expected for statistically independent particle emission, the magnitude of nonstatistical fluctuations in mean transverse momentum is determined to be consistent with zero. Also, no significant nonrandom fluctuations in mean transverse energy are observed. By constructing a fluctuation model with two event classes that preserve the mean and variance of the semi-inclusive p(T) or e(T) spectra, we exclude a region of fluctuations in roots(NN)=130 GeV Au+Au collisions.

Heart rate variability is encoded in the spontaneous discharge of thalamic somatosensory neurones in cat.

1. We studied the spontaneous discharge variability of thalamocortical somatosensory neurones in the awake cat in order to disclose its possible information content. The presence of slow (0.09-1.39 Hz) regular fluctuations in the discharge rate of these cells during the waking state has been previously reported. Oscillations in a similar frequency range are known to characterize the activity of central and peripheral neurones pertaining to the autonomic nervous system and the variability of heart period (RR interval variability). 2. A surrogate data test, performed on our database, confirmed the presence of slow (0.05-1 Hz) non-random fluctuations in firing rate. 3. Linear regression detected the presence of an inverse relationship between the values of RR interval and the concurrent levels of neural discharge. 4. Frequency domain analysis indicated that a significant coupling between the two variability signals preferentially occurred in two frequency bands: in the frequency of the respiratory sinus arrhythmia and in correspondence with a slower rhythm (0.07-0.3 Hz), the two signals being in phase opposition in most of the cases. 5. Coherent fluctuations could also be observed when epochs of evoked activity were analysed, while coupling between the two variability signals appeared to be disrupted after sleep onset. 6. We conclude that RR interval variability, an internally generated dynamic related to basic visceral regulation, is encoded in the discharge of single somatosensory thalamocortical neurones during wakefulness. A possible interaction with the transmission of somatosensory information has to be evaluated.

Methods of testing for sleepiness [corrected

Normal nonrandom fluctuation in daily human performance have been documented for years. Published research reports have shown patterns of workers' errors in reading gas meters, operators' delays in answering calls, drivers' drowsiness, sleepy locomotive engineers' automatic breaking, vehicle crashes, deaths resulting from disease, brief periods of sleep, and sleep latency in structured naps. The authors summarized these data sets and fitted them with a two-peak-per-day cosine curve derived from the population growth function used in chaos theory. Median parameters extracted from the curve fits predicted a sharp peak of sleepiness at 2:30 AM and a secondary peak at 2:30 PM. The shape of the curve was modified by a nonlinear sleep-deprivation factor. The model appeared to be biological rather than behavioral or social because it applied well to disease-related deaths. The authors also review measurement of sleepiness through electroencephalographic monitoring, self-reports, pupillography, and the Multiple Sleep Latency and the Maintenance of Wakefulness Tests.

Multifractal analysis of nucleus-nucleus interactions.

We have performed a multifractal ($G$-moment) analysis of 14.6-200 GeV/nucleon nucleus-nucleus and 200-800 GeV proton-nucleus interactions from KLM and Fermilab E-90 and E-508 emulsion data, including explicit corrections for the finite statistical sample. The corrected slopes of the $G$-moments for protons, $^{16}\mathrm{O}$, $^{28}\mathrm{Si}$, and $^{32}\mathrm{S}$ nuclei show only slight evidence for departures from random behavior, while the normalized entropies appear to show a more consistent departure from randomness, particularly for protons. Given the size of the uncertainties, the results of the fractal analysis are not inconsistent either with results of intermittency analyses for nucleus-nucleus collisions or with the nonrandom behavior previously reported for leptonic and hadronic collisions. However, because of the effects of statistical noise, the fractal analysis is not as sensitive as the intermittency analysis for detecting nonrandom fluctuations.