Optimal Rate of Direct Estimators in Systems of Ordinary Differential Equations Linear in Functions of the Parameters

Many processes in biology, chemistry, physics, medicine, and engineering are modeled by a system of differential equations. Such a system is usually characterized via unknown parameters and estimating their 'true' value is thus required. In this paper we focus on the quite common systems for which the derivatives of the states may be written as sums of products of a function of the states and a function of the parameters. For such a system linear in functions of the unknown parameters we present a necessary and sufficient condition for identifiability of the parameters. We develop an estimation approach that bypasses the heavy computational burden of numerical integration and avoids the estimation of system states derivatives, drawbacks from which many classic estimation methods suffer. We also suggest an experimental design for which smoothing can be circumvented. The optimal rate of the proposed estimators, i.e., their $\sqrt n$-consistency, is proved and simulation results illustrate their excellent finite sample performance and compare it to other estimation approaches

On deconvolution of distribution functions

The subject of this paper is the problem of nonparametric estimation of a continuous distribution function from observations with measurement errors. We study minimax complexity of this problem when unknown distribution has a density belonging to the Sobolev class, and the error density is ordinary smooth. We develop rate optimal estimators based on direct inversion of empirical characteristic function. We also derive minimax affine estimators of the distribution function which are given by an explicit convex optimization problem. Adaptive versions of these estimators are proposed, and some numerical results demonstrating good practical behavior of the developed procedures are presented.Comment: Published in at http://dx.doi.org/10.1214/11-AOS907 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Perspective des patients et des médecins à l'égard du dépistage VIH aux urgences: Une étude prospective transversale

Background At our emergency department (ED), 1% of all patients seen are tested for HIV. This study explored patient- and physician-led barriers and acceptability of rapid HIV testing. Methods Between October 2014 and May 2015, 100 patient-physician pairs were interviewed in the ED of Lausanne University Hospital, Lausanne, Switzerland. Patients completed a questionnaire on HIV risk factors and were offered free rapid HIV testing (INSTITM). For every patient included, the treating physician was asked if HIV testing had been indicated according to the national testing recommendations, mentioned, or offered during the consultation. Results: Of 100 patients, 30 had indications for HIV testing through risk factors or a suggestive presenting complaint. Although 17 patients wished to be tested during their ED consultation, none raised the subject with their physician. Fifty patients accepted rapid testing; no test was reactive. Of 50 patients declining testing, 82% considered themselves not at risk or had recently tested negative and 16% wished to focus on their presenting complaint (PC). Twenty physicians identified patients with testing indications and six offered testing. The main reason for not mentioning or offering testing was the wish to focus on the PC. Conclusion: Patients and physicians at our ED share the barrier of wishing to focus on the PC. Rapid HIV testing offered in parallel to the patient-physician consultation increased the testing rate from 6% (offered by physicians) to 50%. Introducing this service would enable testing of patients not offered tested by their physicians and optimise early HIV diagnoses

Parenthetic function, characterization, and the voice of authority in The Ring and the Book

Who was the masked man in Alexander Dumas’ The Iron Mask? What were the circumstances that led up to his entrapment in the mask? Most of us are fascinated by the mystery that surrounds the use of masks. The ancient Greeks used masks in their dramas to create expressions of sorrow, anger, joy, etc. Masks enabled actors to hide their true selves -- actors merely playing a part. One of the basic character types in Greek drama was the trickster who pretended to be ignorant, “thereby provoking somebody else to reveal his most ludicrous side” (Jones and Wilson 194). In the 19th century, Robert Browning created what Shaw so aptly designated the “Lord of Misrule” (268) – Archangeli, the comic trickster in The Ring and the Book who manipulates language for his own ends. Archangeli uses language as a mask. Language, like the mysterious mask, is not merely an instrument of control over the audience, but enables Archangeli to hold his personality together. By deceiving himself and others, he justifies his own existence. As a lawyer, Archangeli uses rhetorical modes to twist and shape language to express his own attitudes and beliefs. One of the main rhetorical modes contributing to our awareness of Archangeli’s “ludicrous side” is the use of parentheses