scholarly journals Stochastic Theory of Coarse-Grained Deterministic Systems: Martingales and Markov Approximations

2021 ◽  
Author(s):  
Michel Moreau ◽  
Bernard Gaveau
Keyword(s):  
Statistical Physics ◽  
Hamiltonian Dynamics ◽  
Great Part ◽  
Stochastic Theory ◽  
Point Of View ◽  
Coarse Grained ◽  
Martingale Theory ◽  
Deterministic Systems ◽  
Discrete Time Dynamical System ◽  
Coarse Grained State

Many works have been devoted to show that Thermodynamics and Statistical Physics can be rigorously deduced from an exact underlying classical Hamiltonian dynamics, and to resolve the related paradoxes. In particular, the concept of equilibrium state and the derivation of Master Equations should result from purely Hamiltonian considerations. In this chapter, we reexamine this problem, following the point of view developed by Kolmogorov more than 60 years ago, in great part known from the work published by Arnold and Avez in 1967. Our setting is a discrete time dynamical system, namely the successive iterations of a measure-preserving mapping on a measure space, generalizing Hamiltonian dynamics in phase space. Using the notion of Kolmogorov entropy and martingale theory, we prove that a coarse-grained description both in space and in time leads to an approximate Master Equation satisfied by the probability distribution of partial histories of the coarse-grained state.

Rheology of hydrocarbon gels

1950 ◽  
Vol 200 (1061) ◽  
pp. 183-188 ◽  
Keyword(s):  
Mechanical Properties ◽  
Experimental Measurement ◽  
Theoretical Basis ◽  
Continuous Media ◽  
Point Of View ◽  
Coarse Grained ◽  
Testing Instrument ◽  
Fine Grained ◽  
Mineral Oils ◽  
Space And Time

Hydrocarbon gels contain a number of materials, such as rubber, greases, saponified mineral oils, etc., of great interest for various engineering purposes. Specific requirements in mechanical properties have been met by producing gels in appropriately chosen patterns of constituent components of visible, colloidal, molecular and atomic sizes, ranging from coarse-grained aggregates, represented by sponges, foams, emulsions, etc.; to fine-grained and apparently homogeneous ones, represented by optically clear compounds. The engineer who has to deal with the whole range of such materials will adopt a macroscopic point of view, based on an apparent continuity of all the material structures and of the distributions in space and time of the displacements and forces occurring under mechanical actions. It has been possible to determine these distributions in the framework of a comprehensive scheme in which the fundamental principles of the mechanics of continuous media provide the theoretical basis, and a testing instrument of new design, termed Rheogoniometer, the means of experimental measurement (Weissenberg 1931, 1934, 1946, 1947, 1948).

scholarly journals PALEOPROSTŘEDÍ VE SPODNÍM BADENU NA SEVERNÍM OKRAJI BRNA (DIVIŠOVA ČTVRŤ)

2018 ◽  
Vol 25 (1-2) ◽  
Author(s):  
Pavla Tomanová Petrová ◽  
Slavomír Nehyba ◽  
Karel Diviš ◽  
Šárka Hladilová ◽  
Růžena Gregorová ◽  
...  
Keyword(s):  
Point Of View ◽  
Coarse Grained ◽  
Open Sea ◽  
First Time ◽  
Littoral Area

Lower Badenian sediments were studied on the locality Hvozdíkova at the Diviš district, Brno. There were interpreted 4 lithofacies of Neogene (Lower Badenian) sediments (lithofacies M1, M2, Sl, and SGl). Occurrence of basal Lower Badenian clastics is connected with existence of coarse-grained delta (foreset). Overlying pelites document pelagic sedimentation of open sea. Garnet dominates in assemblage of heavy translucent minerals.Rich assemblages of foraminifers, molluscs, spines of echinoids, ostracods and shark fauna were discovered in sediments. Diversified assemblages are dominated by plankton specimens. Species Orbulina suturalis Brön., Praeorbulina glomerosa circularis (Blow) and Globigerinoides bisphericus Todd. indicate the Lower Badenian age.From the point of view of the shark fauna diversity the locality Hvozdíkova is unique; shark fauna is very rare in Lower Badenian clays, and the genera of Squaliolus and Paraetmopterus are identified for the first time. Oysters – especially species Neopycnodonte navicularis (Brocchi) – dominate in Lower Badenian sediments. Small gastropods (for example Cancellaria sp., ?Tornus sp., Rissoa sp., Alvania sp.) probably represent fossils reworked from shallow littoral area. 

Inverse effect and receptor dynamics – Coffee, Opium and Wine's secondary pharmacology

2021 ◽  
Vol 13 (47) ◽  
pp. 125-129
Author(s):  
Andrea Maria Signorini
Keyword(s):  
Great Part ◽  
Small Sample ◽  
Point Of View ◽  
The Body ◽  
Time Dependent ◽  
Cell Sensitivity ◽  
Time Dependent Effect ◽  
Altered Cell ◽  
High Doses ◽  
Clinical Experiments

A homeopathic widespread belief is that the inversion of effect of the drugs in homeopathic medical practice is due to dilution or very low doses, but there are many homeopathic incoherencies. For example the first conception of the similia principle was obtained through planned, small sample, clinical experiments with ponderal/pharmacological doses in healthy and diseased subjects1. Furthermore the classical foundations of the similia principle in Organon2, the primary and secondary actions of drugs, were thought to be connected with opposite, time-dependent reactions of the body to high doses and the inversion of effect was seen in temporal sequence after a strong dose and not after changes of doses, so the idea that dilutions are responsible for inversion of effects is not suitable to the classical theory. And lastly homeopathic provings or pathogenetic trials have frequently mixed, unregarded to the doses, occasional toxicological symptoms and symptoms obtained through diluted substances3, reinforcing the idea that, on healthy subjects, in several cases many substances produce the same symptoms in pharmacological or infinitesimal doses. So at least the dose-dependent inversion of effect is not generalized in a great part of the collected symptoms. Biological foundations to similia principle have to be searched in other directions4, as in different sensitivity to drugs between health and disease, or in different time-dependent effect of drugs on specific, but different, cell sensitivity set point. In the vision described here both these possibilities represent the same phenomenon of altered cell sensitivity. It is aim of this article to show that the original hahnemannian idea to explain homeopathic similia principle starting from a pharmacological and biological point of view with ponderal doses, seems correct, rationally comprehensible and based on modern knowledges. The three pharmacologic examples that best illustrate this reasoning, coffe, opium and wine, will be discussed.

Ground States, Energy Landscape, and Low-Temperature Dynamics of ± J Spin Glasses

2005 ◽  
Author(s):  
Sigismund Kobe ◽  
Jarek Krawczyk
Keyword(s):  
Ising Model ◽  
Spin Glass ◽  
Spin Glasses ◽  
Statistical Physics ◽  
Energy Landscape ◽  
Point Of View ◽  
Model Systems ◽  
Spin Glass Model ◽  
Glass Model ◽  
Physics Literature

The previous three chapters have focused on the analysis of computational problems using methods from statistical physics. This chapter largely takes the reverse approach. We turn to a problem from the physics literature, the spin glass, and use the branch-and-bound method from combinatorial optimization to analyze its energy landscape. The spin glass model is a prototype that combines questions of computational complexity from the mathematical point of view and of glassy behavior from the physical one. In general, the problem of finding the ground state, or minimal energy configuration, of such model systems belongs to the class of NP-hard tasks. The spin glass is defined using the language of the Ising model, the fundamental description of magnetism at the level of statistical mechanics. The Ising model contains a set of n spins, or binary variables si, each of which can take on the value up (si = 1) or down (si= 1).

Characterization of LFG Emissions Factors for MSW Landfills

2019 ◽  
Vol 34 ◽  
pp. 191-196
Author(s):  
Gheorghe Voicu ◽  
Danila Vieru ◽  
Mirela-Nicoleta Dinca
Keyword(s):  
Atmospheric Pressure ◽  
Environmental Changes ◽  
Landfill Gas ◽  
Great Part ◽  
Ghg Emissions ◽  
Point Of View ◽  
Human Beings ◽  
Biodegradation Rate ◽  
Protection Legislation

Conform municipal solid waste (MSW) landfills will continue to be used, in the nearest future, in accordance with environmental protection legislation. Due to this fact, the environmental factors such as: water, air, fauna and vegetation, soil, as well as the human health will be affected. The Greenhouse Gases (GHG) emissions (CH4, CO2, N2O, other nitrogen oxides, water vapor steams) are taken into consideration being responsible for a great part of the world environmental changes, 3÷5%, approximately. It is to be noted that, on the national territories, the GHG emissions should be considered due to a bad management of those. The MSW landfilling allows collecting landfill gas (LFG) in a place by collection and treatment of CH4, CO2 and H2S, for economical purposes and human beings health protection. Methane (CH4) is a strong GHG but has economical value and in the same time, is an important energetic source. Collecting this gas involves important costs. Waste disposal have to be analyzed from the point of view of its enclosed constituents, humidity kept, permeability, biodegradation rate, compacting density, temperature inside the landfill body and atmospheric pressure variations. This article is dedicated to studying the parameters of LFG collection wells, which are used as part of vertical collection systems. For this purpose, the modeling approaches to the main processes occurring in the porous medium of the landfill (MSW) are taken into account.

scholarly journals Exploring the landscape of model representations

2020 ◽  
Vol 117 (39) ◽  
pp. 24061-24068 ◽  
Author(s):  
Thomas T. Foley ◽  
Katherine M. Kidder ◽  
M. Scott Shell ◽  
W. G. Noid
Keyword(s):  
Statistical Physics ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Coarse Graining ◽  
Order Parameters ◽  
Microscopic Model ◽  
Coarse Grained ◽  
Proper Order ◽  
Complex Phenomena ◽  
Protein Fluctuations

The success of any physical model critically depends upon adopting an appropriate representation for the phenomenon of interest. Unfortunately, it remains generally challenging to identify the essential degrees of freedom or, equivalently, the proper order parameters for describing complex phenomena. Here we develop a statistical physics framework for exploring and quantitatively characterizing the space of order parameters for representing physical systems. Specifically, we examine the space of low-resolution representations that correspond to particle-based coarse-grained (CG) models for a simple microscopic model of protein fluctuations. We employ Monte Carlo (MC) methods to sample this space and determine the density of states for CG representations as a function of their ability to preserve the configurational information, I, and large-scale fluctuations, Q, of the microscopic model. These two metrics are uncorrelated in high-resolution representations but become anticorrelated at lower resolutions. Moreover, our MC simulations suggest an emergent length scale for coarse-graining proteins, as well as a qualitative distinction between good and bad representations of proteins. Finally, we relate our work to recent approaches for clustering graphs and detecting communities in networks.

scholarly journals Cognitive rehabilitation and head injury

2011 ◽  
Vol 30 (02) ◽  
pp. 51-54
Author(s):  
Camila Batista dos Santos ◽  
Eberval Gadelha Figueiredo ◽  
Manoel Jacobsen Teixeira
Keyword(s):  
Quality Of Life ◽  
Cognitive Rehabilitation ◽  
Great Part ◽  
Point Of View ◽  
Functional Adaptation ◽  
Compensatory Strategies ◽  
Expected Performance ◽  
Cognitive Benefits ◽  
One Year

AbstractThe present study aims to present the cognitive benefits and the importance of the use of compensatory strategies for a better functional adaptation and for the quality of life in patient that underwent cognitive rehabilitation (CR), after a severe cranioencephalic trauma. A 24 years-old male carried out neuropsychological evaluation after eight months of car accident. CR program developed for one year and four months, with constant establishment of goal, cognitive training and use of compensatory strategies for the difficulties in the daily tasks. It is possible to notice through the neuropsychological revaluation that the cognitive profits with the CR were global, including reaching expected performance for his age group in some functions. There was also observed, reach of great part of the stipulated goals, adaptation to the difficulties in the daily activities through the use of the strategies and consequently improves in the quality of life. This is a case that shows the contribution of the CR for patients who suffered CET, even after the process of spontaneous recuperation, in a moment that, from the clinical point of view, constant sequels keeps in mind.

scholarly journals Interrelation of microstructure and thermodynamic parameters in TiNi alloy during multiple martensitic transformations

2019 ◽  
Vol 298 ◽  
pp. 00002
Author(s):  
Anna Churakova
Keyword(s):  
Thermodynamic Parameters ◽  
Rapid Heating ◽  
Martensitic Transformations ◽  
Coarse Grained ◽  
Tini Alloy ◽  
Thermal Cycles ◽  
Fast Heating ◽  
Heating And Cooling ◽  
Coarse Grained State ◽  
Consistent Increase

The effect of multiple martensitic transformations on the microstructure and thermodynamic parameters of the alloy of the TiNi system was investigated. It was shown that in the Ti50Ni50 alloy, with an increase in the number of thermal cycles with rapid heating and cooling up to n = 100, a consistent increase in the dislocation density occurs, and a decrease in the width of martensitic plates is observed. And also, that in TCs with fast heating and cooling of the Ti50Ni50 alloy in a coarse-grained state, a change in the trend in the temperatures of martensitic transformations is observed — with an increase in the number of thermal cycles to n = 50, they decrease, and at n> 50 the temperatures increase.

Radiation adaptive response and cancer: From the statistical physics point of view

2019 ◽  
Vol 99 (2) ◽  
Author(s):  
Krzysztof W. Fornalski
Keyword(s):  
Adaptive Response ◽  
Statistical Physics ◽  
Point Of View
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