Search results for "continuity"
showing 10 items of 378 documents
Partial self-consistency and analyticity in many-body perturbation theory: Particle number conservation and a generalized sum rule
2016
We consider a general class of approximations which guarantees the conservation of particle number in many-body perturbation theory. To do this we extend the concept of $\Phi$-derivability for the self-energy $\Sigma$ to a larger class of diagrammatic terms in which only some of the Green's function lines contain the fully dressed Green's function $G$. We call the corresponding approximations for $\Sigma$ partially $\Phi$-derivable. A special subclass of such approximations, which are gauge-invariant, is obtained by dressing loops in the diagrammatic expansion of $\Phi$ consistently with $G$. These approximations are number conserving but do not have to fulfill other conservation laws, such…
Continuity correction of pearson’s chi-square test in 2x2 contingency tables: A mini-review on recent development
2022
The Pearson’s chi-square test represents a nonparametric test more used in Biomedicine and Social Sciences, but it introduces an error for 2 x 2 contingency tables, when a discrete probability distribution is approximated with a continuous distribution. The first author to introduce the continuity correction of Pearson’s chi-square test has been Yates F. (1934). Unfortunately, Yates’s correction may tend to overcorrect of p-value, this can implicate an overly conservative result. Therefore many authors have introduced variants Pearson’s chi-square statistic, as alternative continuity correction to Yates’s correction. The goal of this paper is to describe the most recent continuity correctio…
Un sistema formativo ancora da costruire. Riflessioni e proposte per la formazione iniziale degli educatori per la prima infanzia
2022
Mettendo in relazione la formazione iniziale di educatori/educatrici e insegnanti per la prima infanzia con le conoscenze relative allo sviluppo, alle modalità di apprendimento e ai bisogni dei bambini nei primi sei anni di vita, il mio intervento si centra sulla ipotesi di un curriculo formativo unitario. Individua quindi sia le aree disciplinari fondamentali e i possibili contenuti, sia i modelli formativi più efficaci per delineare un profilo professionale specifico, conducendo un approfondimento sull’apprendimento dall’esperienza all’interno dell’Università e sulle modalità di tirocinio maggiormente efficaci. In base alla normativa vigente, delineo poi le criticità del modello formativo…
Uncertainty quantification analysis of the biological Gompertz model subject to random fluctuations in all its parameters
2020
[EN] In spite of its simple formulation via a nonlinear differential equation, the Gompertz model has been widely applied to describe the dynamics of biological and biophysical parts of complex systems (growth of living organisms, number of bacteria, volume of infected cells, etc.). Its parameters or coefficients and the initial condition represent biological quantities (usually, rates and number of individual/particles, respectively) whose nature is random rather than deterministic. In this paper, we present a complete uncertainty quantification analysis of the randomized Gomperz model via the computation of an explicit expression to the first probability density function of its solution s…
El sistema de continuidad como proceso unificador
2007
El sistema de continuidad es un procedimiento de construcción de relatos audiovisuales que tiene como fundamento la causalidad narrativa y un conjunto de normas de elaboración, especialmente en el montaje, cuya finalidad es mostrar al espectador un desarrollo argumental lógico que se desarrolla en un espacio-tiempo diegético coherente. La continuidad, está sometida a un modelo ideológico de representación que condiciona la percepción. La continuidad no es, por lo tanto, un concepto absoluto, sino que evoluciona a lo largo del tiempo. Sin embargo, el sistema de continuidad permanece vigente porque garantiza el predominio de la cadena causal y la inmersión del espectador en el universo diegét…
Two-Dimensional Modeling of a Flat-Plate Photocatalytic Reactor for Oxidation of Indoor Air Pollutants
2007
In this paper we present a two-dimensional (2-D) analysis of a narrow-slit, flat-plate, single-pass, flow-through photocatalytic reactor for air purification. The continuity equation for convection and diffusion in two dimensions, under un-steady-state conditions, was coupled with radiation field modeling and photocatalytic reaction kinetics to model the transient and steady-state behavior of the reactor. The model was applied to the photocatalytic oxidation of trichloroethylene (TCE) in humidified air streams under different experimental conditions. The kinetic parameters determined by a three-dimensional (3-D) computational fluid dynamics model of the reactor were used in the 2-D model si…
Defending the Nordic model: Understanding the moral universe of the Norwegian working class
2021
In recent years, much attention has been paid to the white working class’ concern with their declining position in the neoliberal era. The hypothesis that social and economic insecurity provoke anger and xenophobia are unable to account for the Norwegian case. The Nordic model still acts as a buffer against neoliberal capitalism, making the white Norwegian working class less vulnerable than in comparable countries. This paper will argue that the Norwegian working class has defended the Nordic model by utilising a range of moral values. I use 56 qualitative interviews to examine the morality of the white Norwegian working class. The study is theoretically and methodologically inspired by Bol…
Growth form matters – Crustose lichens on dead wood are sensitive to forest management
2022
Lichens have a vital role in forest ecosystems and they are a threatened group in boreal forests. However, the conservation ecology of the total lichen community has very rarely been studied. Here we studied lichen species and communities, including macrolichens (=foliose and fruticose growth forms) and rarely studied crustose li-chens, on decaying wood in boreal spruce-dominated forests in Finland. We also studied obligate lignicoles that grow only on dead wood and are mostly crustose in growth form. Species richness and community composition were examined on decaying logs and natural or cut stumps of Picea abies at different decay stages (2-5) in 14 stands, half of which were natural or s…
A Novel Self-organizing Neural Technique for Wind Speed Mapping
2009
Systems with high nonlinearities are, in general, very difficult to model. This is particularly true in geostatistics, where the problem of the estimation of a regionalized variable (RV) given only a small amount of measurement stations and a complex terrain surface is very challenging. This paper introduces a novel strategy, which couples the Curvilinear Component Analysis (CCA) and the Generalized Mapping Regressor (GMR). CCA, which is a nonlinear projector of a data manifold, is here used in order to find the intrinsic dimension of the data manifold, just giving an insight on the nonlinearities of the problem. This analysis drives the pre-processing of the data set used for the training …
Lower semicontinuity of weak supersolutions to the porous medium equation
2013
Weak supersolutions to the porous medium equation are defined by means of smooth test functions under an integral sign. We show that nonnegative weak supersolutions become lower semicontinuous after redefinition on a set of measure zero. This shows that weak supersolutions belong to a class of supersolutions defined by a comparison principle.