This study was aimed to analyse the lower limb kinematics during the change of direction (COD) performance with the dominant (DL) and non-dominant (NDL) leg using linear (traditional kinematics) and nonlinear (Self Organising Map-based cluster analysis) approaches. Three 5-0-5 COD performances with the DL and three with the NDL were performed by 23 (aged 21.6 ± 2.3 years) collegiate athletes. No significant difference was observed between the COD duration, and approach speed of DL and NDL. Significantly greater ankle abductions, knee and hip external rotations were identified in COD with DL, compared to NDL (p < .001, d > 0.8). Self Organising Maps portrayed a completely different coordination pattern profile during change of direction performance with the DL and NDL. The cluster analysis illustrated similar inter-individual coordination patterning when participants turned with their DL or NDL. No visible relationship was observed in the cluster analysis of the lower limb joint angles and angular velocities. Outcomes of this study portrayed that coordination patterning (combination of joint angles and the rate of change of angles) could portray the movement patterning differences in different tasks, while a sole investigation on the joint angles or angular velocities may not reveal the underlying mechanisms of movement patterning.

• MeSH
• bérec * fyziologie   MeSH
• biomechanika MeSH
• dolní končetina * fyziologie   MeSH
• funkční lateralita * fyziologie   MeSH
• kotník fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• motorické dovednosti * fyziologie   MeSH
• nelineární dynamika MeSH
• pohyb fyziologie   MeSH
• shluková analýza MeSH
• sportovní výkon * fyziologie   MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Applications of causal techniques to neural time series have increased extensively over last decades, including a wide and diverse family of methods focusing on electroencephalogram (EEG) analysis. Besides connectivity inferred in defined frequency bands, there is a growing interest in the analysis of cross-frequency interactions, in particular phase and amplitude coupling and directionality. Some studies show contradicting results of coupling directionality from high frequency to low frequency signal components, in spite of generally considered modulation of a high-frequency amplitude by a low-frequency phase. We have compared two widely used methods to estimate the directionality in cross frequency coupling: conditional mutual information (CMI) and phase slope index (PSI). The latter, applied to infer cross-frequency phase-amplitude directionality from animal intracranial recordings, gives opposite results when comparing to CMI. Both metrics were tested in a numerically simulated example of unidirectionally coupled Rössler systems, which helped to find the explanation of the contradictory results: PSI correctly estimates the lead/lag relationship which, however, is not generally equivalent to causality in the sense of directionality of coupling in nonlinear systems, correctly inferred by using CMI with surrogate data testing.

• MeSH
• elektroencefalografie * metody   MeSH
• lidé MeSH
• modely neurologické MeSH
• mozek fyziologie   MeSH
• nelineární dynamika * MeSH
• počítačová simulace MeSH
• počítačové zpracování signálu MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Within the framework of continuous pharmaceutical manufacturing, we are interested in statistical modeling of the initial behavior of the production line. Assuming a gradually changing sequence of a suitable product quality characteristic (e.g., the content uniformity), we estimate the so-called point-of-stabilization (PoSt) and construct corresponding confidence regions based on appropriate asymptotic distributions and bootstrap. We investigate linear, quadratic, and nonlinear gradual change models both in homoscedastic and heteroscedastic setup. We propose a new nonlinear Emax gradual change model and show that it is applicable even if the true model is linear. Asymptotic distribution of the PoSt estimator is known only in a homoscedastic linear and quadratic model and, therefore, bootstrap approximations are used to construct one-sided PoSt confidence intervals.

• MeSH
• interval spolehlivosti MeSH
• léčivé přípravky MeSH
• lidé MeSH
• nelineární dynamika * MeSH
• statistické modely * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Thermodynamic acidity constants (acid or acid-base dissociation constants, sometimes called also as ionization constants) and limiting ionic mobilities (both of them at defined temperature, usually 25°C) are the fundamental physicochemical characteristics of a weak electrolyte, that is, weak acid or weak base or ampholyte. We introduce a novel method for determining the data of a weak electrolyte by the nonlinear regression of effective electrophoretic mobility versus buffer composition dependence when measured in a set of BGEs with various pH. To correct the experimental data for zero ionic strength we use the extended Debye-Hückel model and Onsager-Fuoss law with no simplifications. Contrary to contemporary approaches, the nonlinear regression is performed on limiting mobility data calculated by PeakMaster's correction engine, not on the raw experimental mobility data. Therefore, there is no requirement to perform all measurements at a constant ionic strength of the set of BGEs. We devised the computer program AnglerFish that performs the necessary calculations in a user-friendly fashion. All thermodynamic pKa values and limiting electrophoretic mobilities for arbitrarily charged substances having any number of ionic forms are calculated by one fit. The user input consists of the buffer composition of the set of BGEs and experimentally measured effective mobilities of the inspected weak electrolyte.

• MeSH
• algoritmy MeSH
• elektroforéza kapilární metody   MeSH
• elektrolyty analýza   chemie   MeSH
• koncentrace vodíkových iontů MeSH
• nelineární dynamika MeSH
• osmolární koncentrace MeSH
• software * MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Peak shapes in electrophoresis are often distorted from the ideal Gaussian shape due to disturbing phenomena, of which the most important is electromigration dispersion. For fully dissociated analytes, there is a tight analogy between nonlinear models describing a separation process in chromatography and electrophoresis. When the velocity of the separated analyte depends on the concentration of the co-analyte, the consequence is a mutual influence of the analytes couples, which distorts both analyte zones. In this paper, we introduce a nonlinear model of electromigration for the analysis of two co-migrating fully dissociated analytes. In the initial stages of separation, they influence each other, which causes much more complicated peak shapes. The analysis has revealed that the two most important phenomena-the displacement and the tag-along effects-are common both for nonlinear chromatography and electrophoresis, though their description is partly based on rather different phenomena. The comparison between the nonlinear model of electromigration we describe and the numerical computer solution of the original continuity equations has proven an almost perfect agreement. The predicted features in peak shapes in initial stages of separation have been fully confirmed by the experiments.

• MeSH
• chemické modely MeSH
• chromatografie * MeSH
• elektroforéza kapilární * MeSH
• nelineární dynamika * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Aplikace metod kvantitativní elektroencefalografie (QEEG) umožňuje posuzovat mozkovou elektrickou aktivitu s vysokým časovým rozlišením a získávat tak nové časoprostorové informace mimo jiné i o procesech spojených s poruchami nálady a jejich úpravou. Projekt si klade za cíl vyvinout nové metody analýzy EEG signálu, které budou založeny na teorii nelineárních dynamických systémů a umožní identifikovat mozkové procesy spojené s depresivním onemocněním a časně predikovat individuální terapeutickou odpověď. Vývoj těchto metod bude probíhat na souboru retrospektivních dat, získaných u 120 depresívních nemocných před a po 7 dnech nové antidepresivní léčby. Nově vyvinuté indikátory pak budou aplikovány v rámci prospektivního sledování 60 depresivních nemocných s cílem ověřit schopnost nových metod predikovat odpověď na léčbu antidepresivy a srovnat ji se současnými možnostmi prognózy terapeutického efektu u depresívního onemocnění. Očekáváme, že nové přístupy k analýze EEG signálu umožní časně identifikovat neuronální procesy odpovědné za pozitivní léčebnou odpověď.; Application of the quantitative electroencephalography (QEEG) methods allows to assess brain electrical activity with high time resolution enabling thus to obtain new spatiotemporal information i.a. about processes linked to affective disorders and their repair. The aim of the project is to develop new methods of EEG analysis, based on the theory of non-linear dynamics, allowing the elucidation of processes associated with depression and the prediction of individual therapeutic response. The development of these methods will be realized by using the set of retrospective EEG data, obtained from 120 depressive patients at baseline and after 7 days after antidepressive treatment. Newly developed indicators then will be applied to the prospective follow-up of 60 depressive patients, with the aim to validate their predictive ability of treatment response and to compare their efficiency with current prognostic possibilities in depression treatment. We expect that new EEG analysis approaches will achieve the early identification of neuronal processes responsible for treatment outcome.

• MeSH
• antidepresiva MeSH
• deprese terapie   MeSH
• elektroencefalografie MeSH
• nelineární dynamika MeSH
• pozorovací studie jako téma MeSH
• retrospektivní studie MeSH
• výsledek terapie MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• psychiatrie
• neurologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

BACKGROUND: There is strong experimental evidence that physiologic stress from high temperatures is greater if humidity is higher. However, heat indices developed to allow for this have not consistently predicted mortality better than dry-bulb temperature. OBJECTIVES: We aimed to clarify the potential contribution of humidity an addition to temperature in predicting daily mortality in summer by using a large multicountry dataset. METHODS: In 445 cities in 24 countries, we fit a time-series regression model for summer mortality with a distributed lag nonlinear model (DLNM) for temperature (up to lag 3) and supplemented this with a range of terms for relative humidity (RH) and its interaction with temperature. City-specific associations were summarized using meta-analytic techniques. RESULTS: Adding a linear term for RH to the temperature term improved fit slightly, with an increase of 23% in RH (the 99th percentile anomaly) associated with a 1.1% [95% confidence interval (CI): 0.8, 1.3] decrease in mortality. Allowing curvature in the RH term or adding terms for interaction of RH with temperature did not improve the model fit. The humidity-related decreased risk was made up of a positive coefficient at lag 0 outweighed by negative coefficients at lags of 1-3 d. Key results were broadly robust to small model changes and replacing RH with absolute measures of humidity. Replacing temperature with apparent temperature, a metric combining humidity and temperature, reduced goodness of fit slightly. DISCUSSION: The absence of a positive association of humidity with mortality in summer in this large multinational study is counter to expectations from physiologic studies, though consistent with previous epidemiologic studies finding little evidence for improved prediction by heat indices. The result that there was a small negative average association of humidity with mortality should be interpreted cautiously; the lag structure has unclear interpretation and suggests the need for future work to clarify. https://doi.org/10.1289/EHP5430.

• MeSH
• lidé MeSH
• mortalita trendy   MeSH
• nelineární dynamika MeSH
• roční období MeSH
• velkoměsta MeSH
• vlhkost * MeSH
• vysoká teplota * MeSH
• vystavení vlivu životního prostředí statistika a číselné údaje   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Geografické názvy
• velkoměsta MeSH

BACKGROUND: Mood regulation is a complex and poorly understood process. In this study, we aimed to analyze the underlying dynamics of mood regulation in unaffected first degree relatives of patients diagnosed with bipolar disorder using time-series analysis. METHODS: We recruited 30 unaffected first-degree relatives of bipolar disorder patients. Participants rated their mood, anxiety and energy levels using a paper-based visual analog scale; they recorded their sleep and life events as well. Participants provided information on these variables over a three month period, twice per day. We compared their data using Box-Jenkins time series analysis with data from 30 healthy controls (HC) and 30 euthymic bipolar patients (BD) to obtain information on the autocorrelation and cross-correlation of the series, and calculated entropy for mood, anxiety and energy series. RESULTS: We analyzed 14,980 data points: 5200 in the healthy control group; 4970 in the bipolar group and 4810 in the unaffected relatives group. There were no significant differences between groups in terms of age, sex or education levels. Using Kolmogorov-Smirnov test, we found that individual measures were normally distributed in the whole sample (D = 0.23, p > 0.1). Autocorrelation functions for mood in all groups are governed by the ARIMA (1,1,0) model, which means that current values in the series are related to one previous point only. In terms of entropy for the mood series, unaffected relatives and bipolar patients showed lower values [mean (SD) : 1.028 ± 0.679; 1.042 ± 0.680], respectively, compared to healthy controls [(1.476 ± 0.33); F (2,74) = 4.39, p < 0.01]. The same case was seen in the energy series, with lower values in the unaffected relatives and bipolar patient groups [mean (SD) : 1.644 ± 0.566; 1.511 ± 0.879], respectively, compared to healthy controls [2.230 ± 0.531; F(2, 75) = 7.89, p < 0.001]. LIMITATIONS: Low resolution for the visual analog scale. CONCLUSIONS: Using nonlinear analyses, we found that the underlying structure of mood regulation in unaffected relatives is undistinguishable from the one found in bipolar patients. Compared to healthy controls, both bipolar patients and their unaffected relatives showed lower entropy levels, which is in keeping with a more rigid system, not as flexible to cope with the demands of a changing environment.

• MeSH
• afekt * MeSH
• bipolární porucha diagnóza   psychologie   MeSH
• cyklotymní poruchy psychologie   MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• nelineární dynamika MeSH
• sebekontrola psychologie   MeSH
• studie případů a kontrol MeSH
• úzkost psychologie   MeSH
• vizuální analogová stupnice MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

PURPOSE: The aim of this study was to compare gait stability and variability between walking conditions and age groups. METHODS: Twenty-six healthy younger and older females participated. Trunk acceleration in the vertical (V), medial-lateral (ML) and anteriorposterior (AP) directions during 5 minutes walking overground and 3 minutes walking on the treadmill at self-selected speed were recorded. Root mean square and standard deviations of acceleration, stride time and its variability, Lyapunov exponents (LE), multiscale entropy (MSE) and harmonic ratios (HR) were computed. RESULTS: Both age groups showed significantly higher stride time variability and short-term LE in all directions during overground walking. For the older group, overground walking showed higher V and AP standard deviation. Significantly lower values for overground walking were observed for long-term LE (V and ML for the younger group, ML for the older group), HR (ML for the older group) and MSE (V for the older group). Significant age-related differences were found for V long-term LE for overground walking. CONCLUSIONS: The present findings suggest that both linear and advanced computational techniques for gait stability and variability assessment in older adults are sensitive to walking conditions.

• MeSH
• akcelerometrie přístrojové vybavení   MeSH
• chůze fyziologie   MeSH
• entropie * MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• nelineární dynamika * MeSH
• senioři MeSH
• zátěžový test * MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH

In this article we study a nonlinear age-structured consumer population model with density-dependent death and fertility rates, and time delays that model incubation/gestation period. Density dependence we consider combines both positive effects at low population numbers (i.e., the Allee effect) and negative effects at high population numbers due to intra-specific competition of consumers. The positive density-dependence is either due to an increase in the birth rate, or due to a decrease in the mortality rate at low population numbers. We prove that similarly to unstructured models, the Allee effect leads to model multi-stability where, besides the locally stable extinction equilibrium, there are up to two positive equilibria. Calculating derivatives of the basic reproduction number at the equilibria we prove that the upper of the two non-trivial equilibria (when it exists) is locally asymptotically stable independently of the time delay. The smaller of the two equilibria is always unstable. Using numerical simulations we analyze topologically nonequivalent phase portraits of the model.

• MeSH
• biologické modely * MeSH
• hustota populace MeSH
• matematické pojmy MeSH
• mortalita MeSH
• nelineární dynamika MeSH
• počítačová simulace MeSH
• populační dynamika statistika a číselné údaje   MeSH
• porodnost MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH