scholarly journals Causal Geometry

Entropy ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 24
Author(s):  
Pavel Chvykov ◽  
Erik Hoel
Keyword(s):  
Causal Relationship ◽  
Causal Model ◽  
Information Geometry ◽  
Scientific Models ◽  
Coarse Grained ◽  
Model Parameters ◽  
Coarse Grained Model ◽  
Fundamental Part ◽  
The Impact ◽  
Causal Geometry

Information geometry has offered a way to formally study the efficacy of scientific models by quantifying the impact of model parameters on the predicted effects. However, there has been little formal investigation of causation in this framework, despite causal models being a fundamental part of science and explanation. Here, we introduce causal geometry, which formalizes not only how outcomes are impacted by parameters, but also how the parameters of a model can be intervened upon. Therefore, we introduce a geometric version of “effective information”—a known measure of the informativeness of a causal relationship. We show that it is given by the matching between the space of effects and the space of interventions, in the form of their geometric congruence. Therefore, given a fixed intervention capability, an effective causal model is one that is well matched to those interventions. This is a consequence of “causal emergence,” wherein macroscopic causal relationships may carry more information than “fundamental” microscopic ones. We thus argue that a coarse-grained model may, paradoxically, be more informative than the microscopic one, especially when it better matches the scale of accessible interventions—as we illustrate on toy examples.

scholarly journals The impact of long-range dispersal on gene surfing

2020 ◽  
Vol 117 (14) ◽  
pp. 7584-7593 ◽  
Author(s):  
Jayson Paulose ◽  
Oskar Hallatschek
Keyword(s):  
Genetic Variation ◽  
Long Range ◽  
Range Expansion ◽  
Spatial Genetic Structure ◽  
Dispersal Distance ◽  
Coarse Grained ◽  
Coarse Grained Model ◽  
Species Invasions ◽  
Dispersal Distances ◽  
The Impact

Range expansions lead to distinctive patterns of genetic variation in populations, even in the absence of selection. These patterns and their genetic consequences have been well studied for populations advancing through successive short-ranged migration events. However, most populations harbor some degree of long-range dispersal, experiencing rare yet consequential migration events over arbitrarily long distances. Although dispersal is known to strongly affect spatial genetic structure during range expansions, the resulting patterns and their impact on neutral diversity remain poorly understood. Here, we systematically study the consequences of long-range dispersal on patterns of neutral variation during range expansion in a class of dispersal models which spans the extremes of local (effectively short-ranged) and global (effectively well-mixed) migration. We find that sufficiently long-ranged dispersal leaves behind a mosaic of monoallelic patches, whose number and size are highly sensitive to the distribution of dispersal distances. We develop a coarse-grained model which connects statistical features of these spatial patterns to the evolution of neutral diversity during the range expansion. We show that growth mechanisms that appear qualitatively similar can engender vastly different outcomes for diversity: Depending on the tail of the dispersal distance distribution, diversity can be either preserved (i.e., many variants survive) or lost (i.e., one variant dominates) at long times. Our results highlight the impact of spatial and migratory structure on genetic variation during processes as varied as range expansions, species invasions, epidemics, and the spread of beneficial mutations in established populations.

scholarly journals From sectors to speckles: The impact of long-range migration on gene surfing

2019 ◽  
Author(s):  
Jayson Paulose ◽  
Oskar Hallatschek
Keyword(s):  
Genetic Variation ◽  
Long Range ◽  
Range Expansion ◽  
Spatial Genetic Structure ◽  
Dispersal Distance ◽  
Coarse Grained ◽  
Coarse Grained Model ◽  
Species Invasions ◽  
Dispersal Distances ◽  
The Impact

Range expansions lead to distinctive patterns of genetic variation in populations, even in the absence of selection. These patterns and their genetic consequences have been well-studied for populations advancing through successive short-ranged migration events. However, most populations harbor some degree of long-range dispersal, experiencing rare yet consequential migration events over arbitrarily long distances. Although dispersal is known to strongly affect spatial genetic structure during range expansions, the resulting patterns and their impact on neutral diversity remain poorly understood. Here, we systematically study the consequences of long-range dispersal on patterns of neutral variation during range expansion in a class of dispersal models which spans the extremes of local (effectively short-ranged) and global (effectively well-mixed) migration. We find that sufficiently long-ranged dispersal leaves behind a mosaic of monoallelic patches, whose number and size are highly sensitive to the distribution of dispersal distances. We develop a coarse-grained model which connects statistical features of these spatial patterns to the evolution of neutral diversity during the range expansion. We show that growth mechanisms that appear qualitatively similar can engender vastly different outcomes for diversity: depending on the tail of the dispersal distance distribution, diversity can either be preserved (i.e. many variants survive) or lost (i.e. one variant dominates) at long times. Our results highlight the impact of spatial and migratory structure on genetic variation during processes as varied as range expansions, species invasions, epidemics, and the spread of beneficial mutations in established populations.

scholarly journals Reduction of a stochastic model of gene expression: Lagrangian dynamics gives access to basins of attraction as cell types and metastabilty

2020 ◽  
Author(s):  
Elias Ventre ◽  
Thibault Espinasse ◽  
Charles-Edouard Bréhier ◽  
Vincent Calvez ◽  
Thomas Lepoutre ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stochastic Model ◽  
Cell Types ◽  
Basins Of Attraction ◽  
Coarse Grained ◽  
Model Parameters ◽  
Toggle Switch ◽  
Lagrangian Dynamics ◽  
Coarse Grained Model ◽  
A Cell

AbstractDifferentiation is the process whereby a cell acquires a specific phenotype, by differential gene expression as a function of time. This is thought to result from the dynamical functioning of an underlying Gene Regulatory Network (GRN). The precise path from the stochastic GRN behavior to the resulting cell state is still an open question. In this work we propose to reduce a stochastic model of gene expression, where a cell is represented by a vector in a continuous space of gene expression, to a discrete coarse-grained model on a limited number of cell types. We develop analytical results and numerical tools to perform this reduction for a specific model characterizing the evolution of a cell by a system of piecewise deterministic Markov processes (PDMP). Solving a spectral problem, we find the explicit variational form of the rate function associated to a Large deviations principle, for any number of genes. The resulting Lagrangian dynamics allows us to define a deterministic limit, the basins of attraction of which can be identified to cellular types. In this context the quasipotential, describing the transitions between these basins in the weak noise limit, can be defined as the unique solution of an Hamilton-Jacobi equation under a particular constraint. We develop a numerical method for approximating the coarse-grained model parameters, and show its accuracy for a symmetric toggle-switch network. We deduce from the reduced model an analytical approximation of the stationary distribution of the PDMP system, which appears as a beta mixture. Altogether those results establish a rigorous frame for connecting GRN behavior to the resulting cellular behavior, including the calculation of the probability of jumps between cell types.

scholarly journals The Evaluation of M/M/2 Queuing Framework with Two Heterogeneous Servers for Balking and Reneged Customers

2019 ◽  
Vol 9 (1) ◽  
pp. 5402-5408
Keyword(s):  
Quantitative Method ◽  
The Other ◽  
Scientific Models ◽  
Model Parameters ◽  
Heterogeneous Servers ◽  
Working Vacation ◽  
Clump Size ◽  
The Impact ◽  
Vacation Period ◽  
Low Rate

Queuing hypothesis is a quantitative method which comprises in building scientific models of different sorts of lining frameworks. Occupied time of the framework is broke down and mean holding up time in the stationary system processed. At long last, some numerical outcomes are introduced to demonstrate the impact of model parameters on the framework execution measures. The traveling server, nonetheless, comes back to landing which is used to offer at a low rate whereas the other server is occupied. At whatever point the framework ends up and the subsequent server leaves for a working excursion while the principal server stays inert in the framework. These models can be utilized for making expectations about how the framework can change with requests. The framework is examined in the enduring state utilizing lattice geometric strategy. The clients enter the line in the Poisson manner and the time of each bunch size is dared to be circulated exponentially as for mean ward clump size and clients may balk away or renege when the holding up the line of the clients, in general, be exceptionally enormous. This work exhibits the investigation of a recharging input different working excursions line with balking, reneging and heterogeneous servers. Queuing hypothesis manages the investigation of lines and lining conduct. Different execution proportions of the model, for example, anticipated framework length, anticipated balking rate and reneging rate have been talked about. The technique breaks down an M/M/2 lining framework with two heterogeneous servers, one of which is constantly accessible however the different travels without clients sitting tight for service. During a working vacation period, the subsequent server gives administration at a slower rate as opposed to totally ceasing service. The relentless state probabilities of the model are advantageous and recursive strategies.

scholarly journals Water confined in self-assembled ionic surfactant nano-structures

Soft Matter ◽  
2015 ◽  
Vol 11 (12) ◽  
pp. 2469-2478 ◽  
Author(s):  
Samuel Hanot ◽  
Sandrine Lyonnard ◽  
Stefano Mossa
Keyword(s):  
Computer Simulation ◽  
Aqueous Solutions ◽  
Structural Features ◽  
Coarse Grained ◽  
Ionic Surfactants ◽  
Ionic Surfactant ◽  
Coarse Grained Model ◽  
Nano Structures ◽  
Consequent Effect ◽  
The Impact

We present a coarse-grained model for ionic surfactants in explicit aqueous solutions, and study by computer simulation both the impact of water content on the morphology of the system, and the consequent effect of the formed interfaces on the structural features of the absorbed fluid.

Ease of Doing Business and Its Impact on Inward FDI

2018 ◽  
Vol 1 (1) ◽  
pp. 52 ◽  
Author(s):  
Mohamed Tareq Hossain ◽  
Zubair Hassan ◽  
Sumaiya Shafiq ◽  
Abdul Basit
Keyword(s):  
Regression Model ◽  
Causal Relationship ◽  
World Bank ◽  
Least Square ◽  
Doing Business ◽  
Least Square Regression ◽  
Foreign Countries ◽  
Ease Of Doing Business ◽  
The Impact ◽  
Starting A Business

This study investigates the impact of Ease of Doing Business on Inward FDI over the period from 2011 to 2015 across the globe. This study measures ease of doing business using starting a business, getting credit, registering property, paying taxes and enforcing contracts. The research used a sample of 177 countries from 190 countries listed in World Bank. Least square regression model via E-views software used to examine causal relationship. The study found that ease of doing business indicators ‘Enforcing Contracts’ was found to have a positive significant impact on Inward FDI. Nevertheless, ‘Getting Credit’ and ‘Registering Property’ were found to have a negative significant impact on Inward FDI. However, ‘Starting a Business’ and ‘Paying Taxes’ have no significant impact on Inward FDI in the studied timeframe of this research. The findings of the study suggested the ease of doing business enables inward FDI through better contract enforcements, getting credit and registering property. The findings of the research will assist international managers and companies to know the importance of ease of doing business when investing in foreign countries through FDI.

Estimating OLED Display Device Lifetime from pixel and screen brightness and its application

2019 ◽  
Vol 2019 (1) ◽  
pp. 331-338 ◽  
Author(s):  
Jérémie Gerhardt ◽  
Michael E. Miller ◽  
Hyunjin Yoo ◽  
Tara Akhavan
Keyword(s):  
Image Processing ◽  
Power Consumption ◽  
Model Parameters ◽  
Display Device ◽  
Image Processing Algorithm ◽  
Pixel Value ◽  
Device Lifetime ◽  
The Impact ◽  
Oled Display

In this paper we discuss a model to estimate the power consumption and lifetime (LT) of an OLED display based on its pixel value and the brightness setting of the screen (scbr). This model is used to illustrate the effect of OLED aging on display color characteristics. Model parameters are based on power consumption measurement of a given display for a number of pixel and scbr combinations. OLED LT is often given for the most stressful display operating situation, i.e. white image at maximum scbr, but having the ability to predict the LT for other configurations can be meaningful to estimate the impact and quality of new image processing algorithms. After explaining our model we present a use case to illustrate how we use it to evaluate the impact of an image processing algorithm for brightness adaptation.

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