Effects of distance dependence of exciton hopping on the Davydov soliton

The Davydov model of energy transfer in molecular chains is reconsidered assuming the distance dependence of the exciton hopping term. New equations of motion for phonons and excitons are derived within the coherent state approximation. Solving these nonlinear equations result in the existence of Davydov-like solitons. In the case of a dilatational soliton, the amplitude and width is decreased as a results of the mechanism introduced here and above a critical coupling strength our equations do not allow for localized solutions. For compressional solitons, stability is increased.Comment: RevTeX 13 pages, 3 Postscript figure

Polityka makroostrożnościowa i jej wpływ na zmniejszanie ryzyka systemowego

The main objective of this paper is a holistic representation of the idea of macro-supervision, pointing to the need for its implementation and demonstration based on research and historical data that macro-pru­dential policy can significantly prevent the materialization of systemic risk in the banking business. This means that it will be able to coun­teract this risk in both temporal and structural terms, translating into better functioning of the real economy, which the financial system pri­marily serves. The article will present the history of the idea of macro-supervision and its concept in the light of different economic schools. Next, the characteristics of the financial system, sources of systemic risk and macro-prudential policy objectives will be shown. Attention will also be given to the other objectives of this idea. In the next stage of work, a range of policy instruments will be presented.Głównym celem artykułu jest holistyczne przedstawienie idei makro­nadzoru, wskazanie na potrzeby jej implementacji oraz wykazanie na podstawie danych historycznych i badań, że polityka makroostroż­nościowa może istotnie przeciwdziałać materializacji ryzyka syste­mowego w działalności bankowej. Oznacza to, że będzie ona w sta­nie przeciwdziałać temu ryzyku w wymiarze zarówno czasowym, jak i strukturalnym, przekładając się na lepsze funkcjonowanie gospodar­ki realnej, której system finansowy przede wszystkim służy. W pracy została przedstawiona historia idei makronadzoru oraz opisana cha­rakterystyka systemu finansowego, źródła ryzyka systemowego, a tak­że cele i instrumenty polityki makroostrożnościowej

Bringing sociality into the realm of the brain physics

A review of "The Self-Organizing Social Mind"

A continuous model for microtubule dynamics with catastrophe, rescue and nucleation processes

Microtubules are a major component of the cytoskeleton distinguished by highly dynamic behavior both in vitro and in vivo. We propose a general mathematical model that accounts for the growth, catastrophe, rescue and nucleation processes in the polymerization of microtubules from tubulin dimers. Our model is an extension of various mathematical models developed earlier formulated in order to capture and unify the various aspects of tubulin polymerization including the dynamic instability, growth of microtubules to saturation, time-localized periods of nucleation and depolymerization as well as synchronized oscillations exhibited by microtubules under various experimental conditions. Our model, while attempting to use a minimal number of adjustable parameters, covers a broad range of behaviors and has predictive features discussed in the paper. We have analyzed the resultant behaviors of the microtubules changing each of the parameter values at a time and observing the emergence of various dynamical regimes.Comment: 25 pages, 12 figure

Mossbauer study of the Heusler-type Fe2MAl compounds for M = V, Cr, Fe, Co, Ni

The crystal structure and magnetic properties of Fe2MAl compounds for M = V, Cr, Fe, Co and Ni were investigated by X-ray, magnetostatic and Mössbauer effect methods. It was found that the investigated compounds possess not perfectly ordered fcc structure of the L21-type. With increasing number of 3d electrons of M component the transition from the paramagnetic to ferromagnetic behaviour follows. Mössbauer spectra were analysed by a hyperfine field distribution method. They are characterictic of the ferromagnetic phase for M = Fe, Co and Ni and indicated the early observed preference of these atoms for the Fe sites

Crystal order and magnetic properties of Fe2.4V0.6Al alloy studied by magnetostatic and Mössbauer methods

Performed investigations showed that the magnetic properties of the Fe2.4V0.6Al alloy markedly depend on the degree of atomic order of its cubic structure. The atomically disordered alloy with A2 (bcc) type structure exhibits ferromagnetic properties. Its Mössbauer spectra can be described by the hyperfine field distribution connected with various local environments of Fe atoms. Alloys with B2 (sc) and DO3 (fcc) type structure do not exhibit magnetic transition above 4.2 K. High values of the magnetization and its strongly non-linear variation with magnetic field intensity in a wide temperature range suggest the presence of magnetic iron clusters in these alloys. Superparamagnetic relaxation times of the order of 10−9 s and 5 × 10−8 s correspond to the largest magnetic clusters with a magnetic moment of 4 × 103 μB in B2 and 104 μB in DO3-type structure, respectively. Mössbauer spectra of these alloys confirm lack of the magnetic order and also suggest the presence of the Fe magnetic clusters with those relaxation times. It was shown that the increase of atomic order of the crystal structure causes formation of the Fe magnetic clusters and disappearing of the magnetic order

Diffusion of Classical Solitons

We study the diffusion and deformation of classical solitons coupled to thermal noise. The diffusion coefficient for kinks in the $\phi^4$ theory is predicted up to the second order in $kT$. The prediction is verified by numerical simulations. Multiskyrmions in the vector O(3) sigma model are studied within the same formalism. Thermal noise results in a diffusion on the multisoliton collective coordinate space (moduli space). There are entropic forces which tend, for example, to bind pairs of solitons into bi-solitonic molecules.Comment: 5 Revtex pages, 2 .ps file

Generalized in vitro-in vivo relationship (IVIVR) model based on artificial neural networks

Background: The aim of this study was to develop a generalized in vitro-in vivo relationship (IVIVR) model based on in vitro dissolution profiles together with quantitative and qualitative composition of dosage formulations as covariates. Such a model would be of substantial aid in the early stages of development of a pharmaceutical formulation, when no in vivo results are yet available and it is impossible to create a classical in vitro-in vivo correlation (IVIVC)/IVIVR. Methods: Chemoinformatics software was used to compute the molecular descriptors of drug substances (ie, active pharmaceutical ingredients) and excipients. The data were collected from the literature. Artificial neural networks were used as the modeling tool. The training process was carried out using the 10-fold cross-validation technique. Results: The database contained 93 formulations with 307 inputs initially, and was later limited to 28 in a course of sensitivity analysis. The four best models were introduced into the artificial neural network ensemble. Complete in vivo profiles were predicted accurately for 37.6% of the formulations. Conclusion: It has been shown that artificial neural networks can be an effective predictive tool for constructing IVIVR in an integrated generalized model for various formulations. Because IVIVC/IVIVR is classically conducted for 2–4 formulations and with a single active pharmaceutical ingredient, the approach described here is unique in that it incorporates various active pharmaceutical ingredients and dosage forms into a single model. Thus, preliminary IVIVC/IVIVR can be available without in vivo data, which is impossible using current IVIVC/IVIVR procedures