Correlations, Risk and Crisis: From Physiology to Finance

We study the dynamics of correlation and variance in systems under the load of environmental factors. A universal effect in ensembles of similar systems under the load of similar factors is described: in crisis, typically, even before obvious symptoms of crisis appear, correlation increases, and, at the same time, variance (and volatility) increases too. This effect is supported by many experiments and observations of groups of humans, mice, trees, grassy plants, and on financial time series. A general approach to the explanation of the effect through dynamics of individual adaptation of similar non-interactive individuals to a similar system of external factors is developed. Qualitatively, this approach follows Selye's idea about adaptation energy.Comment: 42 pages, 15 figures, misprints corrections, a proof is added, improved journal versio

Evolution of adaptation mechanisms: adaptation energy, stress, and oscillating death

In 1938, H. Selye proposed the notion of adaptation energy and published "Experimental evidence supporting the conception of adaptation energy". Adaptation of an animal to different factors appears as the spending of one resource. Adaptation energy is a hypothetical extensive quantity spent for adaptation. This term causes much debate when one takes it literally, as a physical quantity, i.e. a sort of energy. The controversial points of view impede the systematic use of the notion of adaptation energy despite experimental evidence. Nevertheless, the response to many harmful factors often has general non-specific form and we suggest that the mechanisms of physiological adaptation admit a very general and nonspecific description. We aim to demonstrate that Selye's adaptation energy is the cornerstone of the top-down approach to modelling of non-specific adaptation processes. We analyse Selye's axioms of adaptation energy together with Goldstone's modifications and propose a series of models for interpretation of these axioms. {\em Adaptation energy is considered as an internal coordinate on the `dominant path' in the model of adaptation}. The phenomena of `oscillating death' and `oscillating remission' are predicted on the base of the dynamical models of adaptation. Natural selection plays a key role in the evolution of mechanisms of physiological adaptation. We use the fitness optimization approach to study of the distribution of resources for neutralization of harmful factors, during adaptation to a multifactor environment, and analyse the optimal strategies for different systems of factors

Tunable nonlinear graphene metasurfaces

We introduce the concept of nonlinear graphene metasurfaces employing the controllable interaction between a graphene layer and a planar metamaterial. Such hybrid metasurfaces support two types of subradiant resonant modes, asymmetric modes of structured metamaterial elements ("metamolecules") and graphene plasmons exhibiting strong mutual coupling and avoided dispersion crossing. High tunability of graphene plasmons facilitates strong interaction between the subradiant modes, modifying the spectral position and lifetime of the associated Fano resonances. We demonstrate that strong resonant interaction, combined with the subwavelength localization of plasmons, leads to the enhanced nonlinear response and high efficiency of the second-harmonic generation.Comment: 6 pages, 5 figure

Systemacity and categorization in functioning of verbs

The article focuses on the issues of systemacity in language, the category of causation, functioning of causatives of the informative-modificative class. In this article, the causation is examined from the perspective of functional approach, suggested by A. Bondarko. A verb of causative semantics is related to a more general class on the basis of its essential properties. In the centre of our attention is a lexical causative of interpersonal semantics which is the core of the functional-semantic field of causationyesBelgorod State National Research Universit

Structure of coenopopulations and phytocoenotic confinement of Paeonia tenuifolia L. in floristic complexes of Oka-Don lowland

Paeonia tenuifolia L. is a rare and protected plant of Saratov region classified as 2 (V) vulnerable species. It has been established that in Kalininsky district, Saratov region, this plant is characterized by narrow environmental amplitude and is exerted to anthropogenic impacts, the coenopopulations are isolated from each other. Existence of the species in communities of the meadow–steppe floristic complexes of Kalininsky district has confirmed that peony is heliophyte, xeromesophyte, eutrophic plant and calcicole. Photophily of P. tenuifoliais confirmed first of all by its high abundance and occurrence in open steppe communities. In both coenopopulations of P.tenuifolia, the indices of recovery have been higher than 1 (CP 1 Irec = 3.38, CP 2 Irec = 1.67), that is, the coenopopulations are relatively steady, numerous seeds are generated giving birth to viable individuals. The index of replacement showing the ratio of the density of regrowth to total mature fraction of the population has been higher in CP 1 (Irepl = 0.80) and lower in CP 2 (Irepl = 0.67). Moderate index of maturing evidence long-term existence of the species in the generative state

How do new media contribute to image-making? The case of personalized web-communications on runet

The paper discusses the impact of personalization on image-making activity through new media on Russian Web segment. The authors compare the target audiences and the content of various mass media and evaluate their imagemaking efficiency. The article concludes on perspectives of social networking media in making image of PR-subjects in terms of personalizationyesBelgorod State Universit

Dynamic and Thermodynamic Models of Adaptation

The concept of biological adaptation was closely connected to some mathematical, engineering and physical ideas from the very beginning. Cannon in his "The wisdom of the body" (1932) used the engineering vision of regulation. In 1938, Selye enriched this approach by the notion of adaptation energy. This term causes much debate when one takes it literally, i.e. as a sort of energy. Selye did not use the language of mathematics, but the formalization of his phenomenological theory in the spirit of thermodynamics was simple and led to verifiable predictions. In 1980s, the dynamics of correlation and variance in systems under adaptation to a load of environmental factors were studied and the universal effect in ensembles of systems under a load of similar factors was discovered: in a crisis, as a rule, even before the onset of obvious symptoms of stress, the correlation increases together with variance (and volatility). During 30 years, this effect has been supported by many observations of groups of humans, mice, trees, grassy plants, and on financial time series. In the last ten years, these results were supplemented by many new experiments, from gene networks in cardiology and oncology to dynamics of depression and clinical psychotherapy. Several systems of models were developed: the thermodynamic-like theory of adaptation of ensembles and several families of models of individual adaptation. Historically, the first group of models was based on Selye's concept of adaptation energy and used fitness estimates. Two other groups of models are based on the idea of hidden attractor bifurcation and on the advection--diffusion model for distribution of population in the space of physiological attributes. We explore this world of models and experiments, starting with classic works, with particular attention to the results of the last ten years and open questions.Comment: Review paper, 48 pages, 29 figures, 183 bibliography, the final version accepted in Phys Life Re