Search results for "J2"
showing 10 items of 137 documents
Quantitative ergodicity for some switched dynamical systems
2012
International audience; We provide quantitative bounds for the long time behavior of a class of Piecewise Deterministic Markov Processes with state space Rd × E where E is a finite set. The continuous component evolves according to a smooth vector field that switches at the jump times of the discrete coordinate. The jump rates may depend on the whole position of the process. Under regularity assumptions on the jump rates and stability conditions for the vector fields we provide explicit exponential upper bounds for the convergence to equilibrium in terms of Wasserstein distances. As an example, we obtain convergence results for a stochastic version of the Morris-Lecar model of neurobiology.
A PHASE TRANSITION FOR LARGE VALUES OF BIFURCATING AUTOREGRESSIVE MODELS
2019
We describe the asymptotic behavior of the number $$Z_n[a_n,\infty )$$ of individuals with a large value in a stable bifurcating autoregressive process, where $$a_n\rightarrow \infty $$ . The study of the associated first moment is equivalent to the annealed large deviation problem of an autoregressive process in a random environment. The trajectorial behavior of $$Z_n[a_n,\infty )$$ is obtained by the study of the ancestral paths corresponding to the large deviation event together with the environment of the process. This study of large deviations of autoregressive processes in random environment is of independent interest and achieved first. The estimates for bifurcating autoregressive pr…
Subdifferential and conjugate calculus of integral functions with and without qualification conditions
2023
We characterize the subdifferential and the Fenchel conjugate of convex integral functions by means of respectively the approximate subdifferential and the conjugate of the associated convex normal integrands. The results are stated in Suslin locally convex spaces, and do not require continuity-type qualification conditions on the functions, nor special topological or algebraic structures on the index set. Consequently, when confined to separable Banach spaces, the characterizations of such a subdifferential are obtained using only the exact subdifferential of the given integrand but at nearby points. We also provide some simplifications of our formulas when additional continuity conditions…
On the arithmetic of a family of degree-two K3 surfaces
2018
Let $\mathbb{P}$ denote the weighted projective space with weights $(1,1,1,3)$ over the rationals, with coordinates $x,y,z,$ and $w$; let $\mathcal{X}$ be the generic element of the family of surfaces in $\mathbb{P}$ given by \begin{equation*} X\colon w^2=x^6+y^6+z^6+tx^2y^2z^2. \end{equation*} The surface $\mathcal{X}$ is a K3 surface over the function field $\mathbb{Q}(t)$. In this paper, we explicitly compute the geometric Picard lattice of $\mathcal{X}$, together with its Galois module structure, as well as derive more results on the arithmetic of $\mathcal{X}$ and other elements of the family $X$.
Access to Secondary Education in Albania: Incentives, Obstacles, and Policy Spillovers
2006
When judged either by educational attainment of adult population or by secondary and tertiary enrollment rates, by 2002 Albania compared very unfavorably to most European countries, including its neighbors. This study examines the determinants of secondary enrollment applying unobserved family effect probit model to data from Living Standards Measurement Survey 2002- 2003. The focus of the paper is to investigate the importance of access to school and to further education for enrollment. We find that both absence of a secondary school in the community and the distance from the residence location to a secondary school have strong negative effect on enrollment, controlling for family backgrou…
School aspirations, cognitive skills and wage expectations of French Undergraduates
2013
en ligne : http://cemapre.iseg.utl.pt/educonf/2e3/files/submissions_to_web/Bonnard%20Claire_%20Giret%20Jean-Francois_Lambert-Le%20Mener%20Marielle.pdf; This paper aims to study the earnings expectations of first-year students at a French university and to compare them with the observed earnings of young people in the labour market for that same year. Our findings highlight the importance of the environment in which students make their choices about education. Expected earnings are proportionally higher when their parents seem to be involved in the careers guidance, even controlling for the effect of parental socio-economic status. The positive opinion of parents about the orientation or the…
More hours, more jobs? The employment effects of longer working hours
2014
Increases in standard hours of work have been a contentious policy issue in Germany. Whilst this might directly lead to a substitution of workers by hours, there may also be a positive employment effect due to reduced costs. Moreover, the response of firms may differ between firms that offer overtime and those that do not. For a panel of German plants (2001–2006) drawn from the IAB Establishment Panel, we are the first to analyse the effect of increased standard hours on employment. Using difference-in-difference methods we find that, consistent with theory, overtime plants showed a significant positive employment response, whilst for standard-time plants there is no difference between plan…
The Impact of Working Memory Training on Children’s Cognitive and Noncognitive Skills
2020
Working memory capacity is thought to play an important role for a wide range of cognitive and noncognitive skills such as fluid intelligence, math, reading, the inhibition of pre-potent impulses or more general self-regulation abilities. Because these abilities substantially affect individuals' life trajectories in terms of health, education, and earnings, the question of whether working memory (WM) training can improve them is of considerable importance. However, whether WM training leads to improvements in these far-transfer skills is contested. Here, we examine the causal impact of WM training embedded in regular school teaching by a randomized educational intervention involving a sampl…
Statistics of transitions for Markov chains with periodic forcing
2013
The influence of a time-periodic forcing on stochastic processes can essentially be emphasized in the large time behaviour of their paths. The statistics of transition in a simple Markov chain model permits to quantify this influence. In particular the first Floquet multiplier of the associated generating function can be explicitly computed and related to the equilibrium probability measure of an associated process in higher dimension. An application to the stochastic resonance is presented.
Reliable numerical solution of a class of nonlinear elliptic problems generated by the Poisson-Boltzmann equation
2020
We consider a class of nonlinear elliptic problems associated with models in biophysics, which are described by the Poisson-Boltzmann equation (PBE). We prove mathematical correctness of the problem, study a suitable class of approximations, and deduce guaranteed and fully computable bounds of approximation errors. The latter goal is achieved by means of the approach suggested in [S. Repin, A posteriori error estimation for variational problems with uniformly convex functionals. Math. Comp., 69:481-500, 2000] for convex variational problems. Moreover, we establish the error identity, which defines the error measure natural for the considered class of problems and show that it yields computa…