Исследование взаимной динамики стохастических нормально распределенных процессов при аддитивной амплитудной расстройке между ними

The joint analysis of several signals is essential for better understanding of the principles underlying the complex systems dynamics. We consider three methods for estimating the stability of the relative dynamics of two surrogate processes. The first one is based on calculation of the phase synchronization coefficient S and the second one on estimation of the cross-conditional entropy CE. The third approach uses the average value of the coherence function of the two processes - the coherence coefficient C. We study the sensitivity of these methods in relation to the amplitude randomization between test processes. All methods are applied to analyze two types of normally distributed random stochastic processes, with either short-term correlations characterized by finite correlation time or long-term correlations with theoretically infinite correlation time characterized by Hurst exponents. In our research, we generate two copies of the surrogate process with either short-term or long-term correlations. Then we attribute the additive white noise to one of these copies at first with the uniform distribution and then with the Gaussian distribution and the same variance. Next, we calculate the coefficients that characterize the mutual behavior of the two test processes and estimate their statistical characteristics. It is found that the sensitivity of all methods to Gaussian additive noise is higher than that of uniform one. We show that processes with long-term correlation react more actively to the additive amplitude noise then processes with short-term correlation. The influence of Hurst exponent value for the processes with long-term correlation is expressed for the coefficients S and C. The influence of correlation time is demonstrated for the coefficients S and СЕ. Our results may be useful in investigations of the mutual dynamics of two processes belonging to the considered types. Функционирование сложных систем возможно характеризовать совместными статистическими характеристиками порождаемых этими системами сигналов. Рассмотрены три подхода к оцениванию стабильности взаимного поведения двух тестовых процессов. Первый подход основан на расчете коэф­фициента фазовой синхронизации (КФС) между процессами. Второй метод базируется на определении взаимной условной энтропии (ВУЭ) процессов. Согласно третьему методу для оценивания стабильности взаимной динамики процессов используется среднее значение функции когерентности (ФК). Исследована чувствительность указанных методов к аддитивной амплитудной расстройке между процессами. Рас­ смотрены два типа процессов: с кратковременной зависимостью и заданным временем корреляции (ВК) и с долговременной зависимостью, определяемой значением показателя Херста. В исследованиях генерирова­лись две копии процесса с известными корреляционными свойствами. Затем в одну из копий вносилась ад­дитивная амплитудная помеха с независимыми отсчетами, подчиняющимися равномерному или нормаль­ ному распределению с одинаковой дисперсией. Для каждого типа помехи и каждого значения ее интенсив­ности оценивались статистические характеристики КФС, ВУЭ и ФК. Выявлено, что чувствительность рассмотренных методов к нормально распределенной расстройке выше, чем к равномерной. При этом процессы с долговременной зависимостью активнее реагируют на аддитивную амплитудную расстройку, чем процессы с кратковременной зависимостью. Влияние показателя Херста для процессов с долговременной зависимостью выражено для КФС и ФК. ВК процессов с кратковременной зависимостью влияет на КФС и ВУЭ. Полученные результаты позволяют обоснованно выбрать необходимый метод анализа взаимной динамики процессов, принадлежащий к рассмотренным в настоящей статье типам.

Исследование методов оценивания стабильности взаимного поведения стохастических процессов

The sensitivity of some methods for estimating the mutual dynamic stability of stochastic processes with given correlative properties was studied in relation to the phase detuning between the processes. Two classes of normally distributed random stochastic processes are considered: the processes with short-term correlation and the processes with a long-term correlation, characterized by the specified Hurst coefficients.На примере тестовых процессов с заданными корреляционными свойствами исследована чувствительность методов оценивания стабильности взаимной динамики стохастических процессов к фазовой расстройке между ними. Рассмотрены два класса нормально распределенных стохастических случайных процессов: процессы с кратковременной зависимостью и процессы с долговременной зависимостью, характеризующиеся заданным показателем Херста

Исследование методов оценивания стабильности взаимного поведения стохастических процессов

The sensitivity of some methods for estimating the mutual dynamic stability of stochastic processes with given correlative properties was studied in relation to the phase detuning between the processes. Two classes of normally distributed random stochastic processes are considered: the processes with short-term correlation and the processes with a long-term correlation, characterized by the specified Hurst coefficients.На примере тестовых процессов с заданными корреляционными свойствами исследована чувствительность методов оценивания стабильности взаимной динамики стохастических процессов к фазовой расстройке между ними. Рассмотрены два класса нормально распределенных стохастических случайных процессов: процессы с кратковременной зависимостью и процессы с долговременной зависимостью, характеризующиеся заданным показателем Херста

The impact of Grey Heron (Ardea cinerea L.) colony on soil biogeochemistry and vegetation: a natural long-term in situ experiment in a planted pine forest

Increased anthropogenic pressure including intensification of agricultural activities leads to long-term decline of natural biotopes, with planted forests often considered as promising compensatory response, although reduced biodiversity and ecosystem stability represent their common drawbacks. Here we present a complex investigation of the impact of a large Grey Heron (Ardea cinerea L.) colony on soil biogeochemistry and vegetation in a planted Scots pine forest representing a natural in situ experiment on an engineered ecosystem. After settling around 2006, the colony expanded for 15 years, leading to the intensive deposition of nutrients with feces, food remains and feather thereby considerably altering the local soil biogeochemistry. Thus, lower pH levels around 4.5, 10- and 2-fold higher concentrations of phosphorous and nitrogen, as well as 1.2-fold discrepancies in K, Li, Mn, Zn and Co., respectively, compared to the surrounding control forest area could be observed. Unaltered total organic carbon (Corg) suggests repressed vegetation, as also reflected in the vegetation indices obtained by remote sensing. Moreover, reduced soil microbial diversity with considerable alternations in the relative abundance of Proteobacteria, Firmicutes, Acidobacteriota, Actinobacteriota, Verrucomicrobiota, Gemmatimonadota, Chujaibacter, Rhodanobacter, and Bacillus has been detected. The above alterations to the ecosystem also affected climate stress resilience of the trees indicated by their limited recovery from the major 2010 drought stress, in marked contrast to the surrounding forest (p = 3∙10−5). The complex interplay between geographical, geochemical, microbiological and dendrological characteristics, as well as their manifestation in the vegetation indices is explicitly reflected in the Bayesian network model. Using the Bayesian inference approach, we have confirmed the predictability of biodiversity patterns and trees growth dynamics given the concentrations of keynote soil biogeochemical alternations with correlations R > 0.8 between observations and predictions, indicating the capability of risk assessment that could be further employed for an informed forest management

Ассоциации полиморфных вариантов rs2305619 и rs3816527 гена пентраксина-3 (PTX3) с особенностями клинического течения и исходов у пациентов с гипертрофической кардиомиопатией: результаты 11-летнего наблюдения.

The objective of this study was to determine the association of polymorphic variants rs2305619 and rs3816527 of the PTX3 gene with clinical profile and outcomes in hypertrophic cardiomyopathy (HCM) patients.Methods and materials. The study population consisted of 153 patients ≥18 years old with a confirmed diagnosis of HCM. The control group included 200 healthy donors. Duration of follow-up was 11 years (2008–2019 yrs.). The study design included a new model for determining variants of the clinical profile and outcomes of HCM. Polymorphic variants rs2305619 and rs3816527 of the PTX3 gene were genotyped by polymerase chain reaction.Results. The mortality rate in patients ≥18 years old with 1, 2 and 3 adverse pathways of HCM progression was significantly higher, compared with those without adverse pathways (р<0.001). A combination of chronic heart failure (CHF) with midrange and reduced LVEF (<49 %) with 1, 2 and 3 adverse pathways in HCM patients occurred more frequently, compared with those who had CHF with preserved LVEF (≥50 %) (odds ratio (OR) = 0.168, 95 % confidence interval (CI) =0.068–0.412, р<0.001). The genetic testing showed no significant differences in genotype and allele frequencies of polymorphic variants rs2305619 and rs3816527 of the PTX3 gene in patients with HCM and control groups. It was found a tendency for increase in GG genotype frequency (p<0.068) and significant increase in G allele frequency of rs2305619 of the PTX3 gene in HCM patients ≥18 years old and CHF with mid-range and reduced LVEF (<49 %) (A:G, OR=0.521, 95 % CI=0.301–0.902, p<0.019). HCM patients (age – 63 [58; 75] years) and type 2 diabetes mellitus demonstrated high prevalence in AG and GG genotypes (p<0.008) and G allele frequencies of rs2305619 of the PTX3 gene (A:G, OR =1.952, 95 % CI=1.076–3.542, p<0.026).Conclusions. HCM progression along 1 and more adverse pathways in patients ≥18 years old has been characterized with adverse outcome. G allele of rs2305619 of the PTX3 gene is associated with CHF with mid-range and reduced LVEF (<49 %) in HCM patients ≥18 years old. The associations of G allele and AG and GG genotypes of rs2305619 of the PTX3 gene with diabetes type 2 are observed in elderly HCM patients.Цель – изучить ассоциации полиморфных вариантов rs2305619 и rs3816527 гена пентраксина-3 (PTX3) с особенностями клинического течения и исходов у пациентов с гипертрофической кардиомиопатией (ГКМП).Методы и материалы. В исследование (2008–2019) включены 153 пациента в возрасте ≥18 лет с подтвержденным диагнозом ГКМП. Группу контроля составили 200 практически здоровых человек. Дизайн исследования включал в себя новую модель определения вариантов клинического течения и исходов ГКМП. Полиморфные варианты rs2305619 и rs3816527 гена PTX3 были идентифицированы методом полимеразной цепной реакции.Результаты. У пациентов с ГКМП в возрасте ≥18 лет при наличии одного, двух и трех путей прогрессирования заболевания смертность за 11 лет значимо превышала аналогичный показатель у пациентов с малосимптомным течением (р<0,001). Хроническая сердечная недостаточность (ХСН) со средней и сниженной фракцией выброса левого желудочка (ФВ ЛЖ) (<49 %) значимо чаще сочеталась с наличием одного, двух и трех путей прогрессирования заболевания, по сравнению с ХСН с сохраненной ФВ ЛЖ (≥50 %) (ОШ=0,168, 95 % ДИ=0,068–0,412, р<0,001). Значимых различий в распределении генотипов и аллелей полиморфных вариантов rs2305619 и rs3816527 гена PTX3 у больных ГКМП и контрольной группе получено не было. Аллель G rs2305619 гена PTX3 определялся достоверно чаще у пациентов с ГКМП и ХСН со средней и сниженной ФВ ЛЖ (<49 %), по сравнению с сохраненной ФВ ЛЖ (≥50 %) (A:G, ОШ=0,521, 95 % ДИ=0,301–0,902, p<0,019). Была определена тенденция к преобладанию генотипа GG rs2305619 гена PTX3 при наличии ХСН со средней и сниженной ФВ ЛЖ (<49 %) (p<0,068). У пациентов с ГКМП и сахарным диабетом (СД) II типа (возраст – 63 [58; 75] года) статистически значимо преобладали генотипы AG и GG (p<0,008) и аллель G rs2305619 гена PTX3 (A:G, ОШ =1,952, 95 % ДИ=1,076–3,542, p<0,026)

Service delays in strongly linked network communities

We analyze aggregated traffic dynamics obtained from strongly linked network communities. Our results based on two empirical data traces from university campus networks indicate that neglecting the statistical links between traffic patterns generated by individual network nodes leads to the drastic underestimation of both waiting and sojourn times. We also show that similar effects can be observed in simulated traffic patterns obtained by agent based modeling. Moreover, we suggest several indices that could be used to quantify the links between nodes and show their relation with the queuing system performance indicators

Investigation of Some Methods for Estimating the Mutual Dynamic Stability of Stochastic Processes

The sensitivity of some methods for estimating the mutual dynamic stability of stochastic processes with given correlative properties was studied in relation to the phase detuning between the processes. Two classes of normally distributed random stochastic processes are considered: the processes with short-term correlation and the processes with a long-term correlation, characterized by the specified Hurst coefficients

Investigation of Mutual Behavior of Stochastic Normally Distributed Processes with Additive Amplitude Randomization

The joint analysis of several signals is essential for better understanding of the principles underlying the complex systems dynamics. We consider three methods for estimating the stability of the relative dynamics of two surrogate processes. The first one is based on calculation of the phase synchronization coefficient S and the second one on estimation of the cross-conditional entropy CE. The third approach uses the average value of the coherence function of the two processes - the coherence coefficient C. We study the sensitivity of these methods in relation to the amplitude randomization between test processes. All methods are applied to analyze two types of normally distributed random stochastic processes, with either short-term correlations characterized by finite correlation time or long-term correlations with theoretically infinite correlation time characterized by Hurst exponents. In our research, we generate two copies of the surrogate process with either short-term or long-term correlations. Then we attribute the additive white noise to one of these copies at first with the uniform distribution and then with the Gaussian distribution and the same variance. Next, we calculate the coefficients that characterize the mutual behavior of the two test processes and estimate their statistical characteristics. It is found that the sensitivity of all methods to Gaussian additive noise is higher than that of uniform one. We show that processes with long-term correlation react more actively to the additive amplitude noise then processes with short-term correlation. The influence of Hurst exponent value for the processes with long-term correlation is expressed for the coefficients S and C. The influence of correlation time is demonstrated for the coefficients S and СЕ. Our results may be useful in investigations of the mutual dynamics of two processes belonging to the considered types