Results 221 to 230 of about 487,019 (287)

Z‐residuals diagnostics for Cox models: Functional‐form misspecification versus nonproportional hazards

open access: yesCanadian Journal of Statistics, EarlyView.
Abstract Primary biliary cholangitis (PBC) is a progressive autoimmune cholestatic disease for which modelling death, with transplantation as a competing event, is clinically important. Cox proportional hazards (PH) models are widely used, but standard diagnostics detect lack of fit without distinguishing non‐PH from misspecified covariate functions ...
Tingxuan Wu, Cindy Feng, Longhai Li
wiley   +1 more source

Front Propagation Through a Perforated Wall

open access: yesCommunications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We consider a bistable reaction– diffusion equation ut=Δu+f(u)$u_t=\Delta u +f(u)$ on RN${\mathbb {R}}^N$ in the presence of an obstacle K$K$, which is a wall of infinite span with many holes. More precisely, K$K$ is a closed subset of RN${\mathbb {R}}^N$ with smooth boundary such that its projection onto the x1$x_1$‐axis is bounded and that ...
Henri Berestycki   +2 more
wiley   +1 more source

A Geometric Characterization of Steady Laminar Flow

open access: yesCommunications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We study the steady states of the Euler equations on the periodic channel or annulus. We show that if these flows are laminar (layered by closed non‐contractible streamlines which foliate the domain), then they must be either parallel or circular flows.
Theodore D. Drivas, Marc Nualart
wiley   +1 more source

Compact Manifolds With Unbounded Nilpotent Fundamental Groups and Positive Ricci Curvature

open access: yesCommunications on Pure and Applied Mathematics, EarlyView.
ABSTRACT It follows from the work of Kapovitch and Wilking that a closed manifold with nonnegative Ricci curvature has a uniformly almost nilpotent fundamental group. Leftover questions and conjectures, have asked if in this context the fundamental group is actually uniformly almost abelian. The main goal of this work is to construct examples (Mk9,gk)$(
Elia Bruè, Aaron Naber, Daniele Semola
wiley   +1 more source

Planar Coulomb Gas on a Jordan Arc at Any Temperature

open access: yesCommunications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We study a planar Coulomb gas confined to a sufficiently smooth Jordan arc γ$\gamma$ in the complex plane, at inverse temperature β>0$\beta > 0$. Let Z¯nβ(γ)=Znβ(γ)((2cap(γ))βn2/2e(1−β/2)n(H(νe,γ)−H(νe,I)),$$\begin{equation*} \bar{Z}_{n}^\beta (\gamma)=\frac{Z_n^\beta (\gamma)}{((2\text{cap}(\gamma))^{\beta n^2/2}e^{(1-\beta /2)n(H(\nu _{e ...
K. Courteaut, K. Johansson, F. Viklund
wiley   +1 more source

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