scholarly journals Application of Asymmetrical Statistical Distributions for 1D Simulation of Solute Transport in Streams

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2145
Author(s):  
Sokáč ◽  
Velísková ◽  
Gualtieri
Keyword(s):  
Probability Distributions ◽  
New Approach ◽  
Dead Zones ◽  
Advection Dispersion ◽  
Small Streams ◽  
Computational Speed ◽  
Transient Storage Zones ◽  
The One ◽  
Published Research ◽  
Substance Transport

Analytical solutions of the one-dimensional (1D) advection–dispersion equations, describing the substance transport in streams, are often used because of their simplicity and computational speed. Practical computations, however, clearly show the limits and the inaccuracies of this approach. These are especially visible in cases where the streams deform concentration distribution of the transported substance due to hydraulic and morphological conditions, e.g., by transient storage zones (dead zones), vegetation, and irregularities in the stream hydromorphology. In this paper, a new approach to the simulation of 1D substance transport is presented, adapted, and tested on tracer experiments available in the published research, and carried out in three small streams in Slovakia with dead zones. Evaluation of the proposed methods, based on different probability distributions, confirmed that they approximate the measured concentrations significantly better than those based upon the commonly used Gaussian distribution. Finally, an example of the application of the proposed methods to an iterative (inverse) task is presented.

scholarly journals 421 - Mood disorders and its relationship with cognitive impairment and dementia

2020 ◽  
Vol 32 (S1) ◽  
pp. 137-137
Author(s):  
Sandra Torres ◽  
Andreia Lopes
Keyword(s):  
Cognitive Impairment ◽  
Mood Disorders ◽  
Neuronal Loss ◽  
Neurocognitive Impairment ◽  
Attention And Memory ◽  
Psychiatric Illnesses ◽  
Neurocognitive Functions ◽  
The Many ◽  
The One ◽  
Published Research

ABSTRACT:Mood disorders are common psychiatric illnesses that represent a major cause of disability worldwide. With life expectancy and the percentage of elderly people rising in many developed and undeveloped countries around the globe, cognitive impairment and dementia are gaining a societal importance. The relation between mood disorders and cognitive function is a twofold. On the one hand, cognitive deficits within mood disorders have been studied extensively, in which there seems to be a persistent neurocognitive impairment, both in acute phases and in interepisodic euthymic phases. Although results have not always been consistent, an overall pattern of specific impairments – in executive function, attention and memory - has become evident. On the other hand, recent research suggests that mood disorders, in general, may be risk factors for the development of mild cognitive impairment and dementia. In this sense, of the many models for the association of mood disorders and dementia, two are favored by several authors. One suggests that mood disorders are a risk factor for earlier clinical manifestation of dementia. The second sees mood disorders as the cause of dementing states, for instance through neuronal loss via dysregulation of the glucocorticoid cascade. In fact, there is suggestion that impairment of neuroplasticity may underlie the pathophysiology of mood disorders as such, and not only of neurocognitive impairment. In some patients, specific neurocognitive functions may be present before the onset of mood disorder and may constitute a trait factor or even an endophenotype. The aim of the present work is to, through a basic narrative review of published research on the main databases, summarize the main evidences of the association of mood disorders and dementia.

Initial-boundary value problems for the one-dimensional linear advection–dispersion equation with decay

2020 ◽  
Vol 75 (8) ◽  
pp. 713-725 ◽  
Author(s):  
Guenbo Hwang
Keyword(s):  
Boundary Conditions ◽  
Dirichlet Boundary ◽  
Boundary Value ◽  
Initial Boundary ◽  
Initial Boundary Value Problems ◽  
One Dimensional ◽  
Advection Dispersion ◽  
Asymptotically Periodic ◽  
The One ◽  
Initial Boundary Value

AbstractInitial-boundary value problems for the one-dimensional linear advection–dispersion equation with decay (LAD) are studied by utilizing a unified method, known as the Fokas method. The method takes advantage of the spectral analysis of both parts of Lax pair and the global algebraic relation coupling all initial and boundary values. We present the explicit analytical solution of the LAD equation posed on the half line and a finite interval with general initial and boundary conditions. In addition, for the case of periodic boundary conditions, we show that the solution of the LAD equation is asymptotically t-periodic for large t if the Dirichlet boundary datum is periodic in t. Furthermore, it can be shown that if the Dirichlet boundary value is asymptotically periodic for large t, then so is the unknown Neumann boundary value, which is uniquely characterized in terms of the given asymptotically periodic Dirichlet boundary datum. The analytical predictions for large t are compared with numerical results showing the excellent agreement.

A new approach to bracket prediction in the NCAA Men’s Basketball Tournament based on a dual-proportion likelihood

2015 ◽  
Vol 11 (1) ◽  
Author(s):  
Ajay Andrew Gupta
Keyword(s):  
National Collegiate Athletic Association ◽  
Expert Knowledge ◽  
Probability Model ◽  
Expected Value ◽  
Division I ◽  
Prediction System ◽  
New Approach ◽  
Men's Basketball ◽  
Popular Interest ◽  
The One

AbstractThe widespread proliferation of and interest in bracket pools that accompany the National Collegiate Athletic Association Division I Men’s Basketball Tournament have created a need to produce a set of predicted winners for each tournament game by people without expert knowledge of college basketball. Previous research has addressed bracket prediction to some degree, but not nearly on the level of the popular interest in the topic. This paper reviews relevant previous research, and then introduces a rating system for teams using game data from that season prior to the tournament. The ratings from this system are used within a novel, four-predictor probability model to produce sets of bracket predictions for each tournament from 2009 to 2014. This dual-proportion probability model is built around the constraint of two teams with a combined 100% probability of winning a given game. This paper also performs Monte Carlo simulation to investigate whether modifications are necessary from an expected value-based prediction system such as the one introduced in the paper, in order to have the maximum bracket score within a defined group. The findings are that selecting one high-probability “upset” team for one to three late rounds games is likely to outperform other strategies, including one with no modifications to the expected value, as long as the upset choice overlaps a large minority of competing brackets while leaving the bracket some distinguishing characteristics in late rounds.

scholarly journals Symmetry breakdown and coupling constants of leptons

2007 ◽  
Vol 79 (2) ◽  
pp. 195-208 ◽  
Author(s):  
Gil C. Marques ◽  
Dominique Spehler
Keyword(s):  
Coupling Constants ◽  
Electroweak Interactions ◽  
New Approach ◽  
Fundamental Interactions ◽  
Electromagnetic Interactions ◽  
Symmetry Breakdown ◽  
A Value ◽  
Intermediate Bosons ◽  
The One ◽  
The Way

Based on a new approach to symmetries of the fundamental interactions we deal, in this paper, with the electroweak interactions of leptons. We show that the coupling constants, arising in the way leptons are coupled to intermediate bosons, can be understood as parameters associated to the breakdown of SU(2) and parity symmetries. The breakdown of both symmetries is characterized by a new parameter (the asymetry parameter) of the electroweak interactions. This parameter gives a measure of the strength of breakdown of symmetries. We analyse the behaviour of the theory for three values of this parameter. The most relevant value is the one for which only the electromagnetic interactions do not break parity (the maximally allowed left-right asymetric theory). Maximamally allowed parity asymmetry is a requirement that is met for a value of Weinberg's theta-angle that is quite close to the experimental value of this parameter.

scholarly journals The Sum and Difference of Two Lognormal Random Variables

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
C. F. Lo
Keyword(s):  
Stochastic Process ◽  
Probability Distributions ◽  
Operator Splitting ◽  
Splitting Method ◽  
Unified Approach ◽  
New Approach ◽  
Numerical Examples ◽  
Operator Splitting Method ◽  
Approximate Probability ◽  
Analytical Series

We have presented a new unified approach to model the dynamics of both the sum and difference of two correlated lognormal stochastic variables. By the Lie-Trotter operator splitting method, both the sum and difference are shown to follow a shifted lognormal stochastic process, and approximate probability distributions are determined in closed form. Illustrative numerical examples are presented to demonstrate the validity and accuracy of these approximate distributions. In terms of the approximate probability distributions, we have also obtained an analytical series expansion of the exact solutions, which can allow us to improve the approximation in a systematic manner. Moreover, we believe that this new approach can be extended to study both (1) the algebraic sum ofNlognormals, and (2) the sum and difference of other correlated stochastic processes, for example, two correlated CEV processes, two correlated CIR processes, and two correlated lognormal processes with mean-reversion.

scholarly journals Modern vision for critical flow in an egg-shaped section

2021 ◽  
Author(s):  
Hachemi Rachedi Lamia ◽  
Lakehal Moussa ◽  
Achour Bachir
Keyword(s):  
Froude Number ◽  
Critical Regime ◽  
Critical Flow ◽  
New Approach ◽  
Smooth Channel ◽  
Critical Flow Regime ◽  
Modern Vision ◽  
The One ◽  
Definition Of ◽  
Steep Slopes

Abstract The critical regime plays a primordial role in the study of gradually varying flows by classifying flow regimes and slopes. Through this work, a new approach is proposed to analyze critical flow regime in an egg-shaped channel. Based on both the definition of Froude number and Achour and Bedjaoui general discharge relationship, a relation between critical and normal depths is derived and then graphically represented for the particular case of a smooth channel characterized by a generating diameter equal to one meter. The results show the influence of the slope on the frequency of occurrence of the critical regime. At the same time and independently of the flow rate, a very advantageous approach for the calculation of the Froude number has been proposed. The study shows that there are six zones to differentiate the various flow states, namely: on the one hand for steep slopes two subcritical zones interspersed by a supercritical zone and on the other hand for mild slopes a zone corresponding to uniform flow, an area where the flow is probably gradually varied and finally an area where the flow is abruptly varied. Based on the specific energy equation, a validation process concluded that the proposed relationships were reliable.

scholarly journals Measuring hospital spatial wingspan by using a discrete choice model with utility-threshold

2018 ◽  
Author(s):  
Saley Issa ◽  
Ribatet Mathieu ◽  
Molinari Nicolas
Keyword(s):  
Monte Carlo ◽  
Discrete Choice ◽  
Choice Model ◽  
Discrete Choice Models ◽  
Mcmc Methods ◽  
Hospital Competition ◽  
Policy Makers ◽  
New Approach ◽  
Asthma Patients ◽  
The One

AbstractPolicy makers increasingly rely on hospital competition to incentivize patients to choose high-value care. Travel distance is one of the most important drivers of patients’ decision. The paper presents a method to numerically measure, for a given hospital, the distance beyond which no patient is expected to choose the hospital for treatment by using a new approach in discrete choice models. To illustrate, we compared 3 hospitals attractiveness related to this distance for asthma patients admissions in 2009 in Hérault (France), showing, as expected, CHU Montpellier is the one with the most important spatial wingspan. For estimation, Monte Carlo Markov Chain (MCMC) methods are used.

scholarly journals An approximate method for 1-D simulation of pollution transport in streams with dead zones

2018 ◽  
Vol 66 (4) ◽  
pp. 437-447 ◽  
Author(s):  
Marek Sokáč ◽  
Yvetta Velísková ◽  
Carlo Gualtieri
Keyword(s):  
Approximate Method ◽  
Statistical Evaluation ◽  
Pollution Transport ◽  
Dead Zones ◽  
Advection Diffusion Equation ◽  
Gumbel’S Distribution ◽  
Novel Method ◽  
Substance Transport ◽  
Better Than ◽  
Tracer Experiments

Abstract Analytical solutions describing the 1D substance transport in streams have many limitations and factors, which determine their accuracy. One of the very important factors is the presence of the transient storage (dead zones), that deform the concentration distribution of the transported substance. For better adaptation to such real conditions, a simple 1D approximation method is presented in this paper. The proposed approximate method is based on the asymmetric probability distribution (Gumbel’s distribution) and was verified on three streams in southern Slovakia. Tracer experiments on these streams confirmed the presence of dead zones to various extents, depending mainly on the vegetation extent in each stream. Statistical evaluation confirms that the proposed method approximates the measured concentrations significantly better than methods based upon the Gaussian distribution. The results achieved by this novel method are also comparable with the solution of the 1D advection-diffusion equation (ADE), whereas the proposed method is faster and easier to apply and thus suitable for iterative (inverse) tasks.

Possibilistic Uncertainty Quantification in 1-D Consolidation Problems

2021 ◽  
Author(s):  
Djamalddine Boumezerane
Keyword(s):  
Uncertainty Quantification ◽  
Probability Distributions ◽  
Uncertainty Propagation ◽  
Possibility Distribution ◽  
Coefficient Of Consolidation ◽  
Consolidation Process ◽  
Possibility Distributions ◽  
Coverage Function ◽  
The One ◽  
Measure Of Uncertainty

Abstract In this study, we use possibility distribution as a basis for parameter uncertainty quantification in one-dimensional consolidation problems. A Possibility distribution is the one-point coverage function of a random set and viewed as containing both partial ignorance and uncertainty. Vagueness and scarcity of information needed for characterizing the coefficient of consolidation in clay can be handled using possibility distributions. Possibility distributions can be constructed from existing data, or based on transformation of probability distributions. An attempt is made to set a systematic approach for estimating uncertainty propagation during the consolidation process. The measure of uncertainty is based on Klir's definition (1995). We make comparisons with results obtained from other approaches (probabilistic…) and discuss the importance of using possibility distributions in this type of problems.

Positive Technology for Helping People Cope with Stress

2021 ◽  
pp. 787-814
Author(s):  
Daniela Villani ◽  
Pietro Cipresso ◽  
Andrea Gaggioli ◽  
Giuseppe Riva
Keyword(s):  
Personal Growth ◽  
New Technologies ◽  
Well Being ◽  
Affective States ◽  
Coping With Stress ◽  
General Process ◽  
New Approach ◽  
Effective Interventions ◽  
Potential Capacity ◽  
The One

The emerging convergence of new technologies and health care is offering a new approach to support effective interventions. This chapter aims to describe how Positive Technology can help people cope with stress in several contexts. On the one hand, the potential capacity of sensor technologies to offer individuals the technology with which to monitor certain biological signals known to be associated with stress might serve to promote engagement with a mediated experience for stress management. On the other hand, the chapter focuses on the hedonic and eudaimonic experiences supported by technology in terms of inducing positive affective states and supporting personal growth by teaching strategies to reduce stress and enhance well-being. To further connect mediated experiences with real ones, the Interreality approach (IR) allows for the combination of assessment and intervention as inseparable parts of the general process of coping with stress.

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