Bidding Behavior in the SNB's Repo Auctions

The Swiss National Bank (SNB) provides reserves to market participants via fixed rate tender auctions. We analyze the banks' bidding behavior and identify the determinants for the decision to participate as well as on the amount to tender. Therefore, we estimate bidding functions for banks which participate regularly in the SNB's auctions. We find that a bank's bids from the previous day and the amount of maturing repo operations with the SNB have for most banks a significant effect. The autonomous factors (government balances at the SNB and currency in circulation) are of only minor importance. A further determinant of the bidding behavior is the attractiveness of the SNB's auction rate compared to the prevailing interbank market repo rate. The spread of unsecured and repo rates as well as the attractiveness of funding Euros indirectly via a Swiss franc repo transaction with the SNB are only for few banks significant. Further, the question is addressed whether the bidding behavior changed in the financial market crisis of 2007/2008. There is little evidence of a systematic change in bidding behavior in the crisis. This results from the fact that the SNB has addressed the volatile demand for reserves in the crisis with overnight fine-tuning operations.Open Market Operations, Bidding Behavior, FixedRate Tender Auction, Repo, Switzerland

Atlas-Based Prostate Segmentation Using an Hybrid Registration

Purpose: This paper presents the preliminary results of a semi-automatic method for prostate segmentation of Magnetic Resonance Images (MRI) which aims to be incorporated in a navigation system for prostate brachytherapy. Methods: The method is based on the registration of an anatomical atlas computed from a population of 18 MRI exams onto a patient image. An hybrid registration framework which couples an intensity-based registration with a robust point-matching algorithm is used for both atlas building and atlas registration. Results: The method has been validated on the same dataset that the one used to construct the atlas using the "leave-one-out method". Results gives a mean error of 3.39 mm and a standard deviation of 1.95 mm with respect to expert segmentations. Conclusions: We think that this segmentation tool may be a very valuable help to the clinician for routine quantitative image exploitation.Comment: International Journal of Computer Assisted Radiology and Surgery (2008) 000-99

Reiterated homogenization of a cavitation problem in thin films mechanics

This paper deals with the coupling of two major problems in lubrication theory: cavitation phenomena and roughness of the surfaces in relative motion: cavitation is defined as the rupture of the continuous film due to the formation of air bubbles, leading to the presence of a liquid-gas mixture. For this, the Elrod-Adams model (which is a pressure-saturation model) is classically used to describe the behavior of a viscous cavitated flow in the lubrication framework. However, in practical situations, the surfaces of the devices are rough, due to manufacturing processes which induce defaults. Thus, we study the behavior of the solution, when highly oscillating roughness effects on the rigid surfaces occur. In particular, we deal with the reiterated homogenization of this elliptic-hyperbolic problem, using periodic unfolding methods. We define a homogenized problem in the most general case, pointing out the fact that it leads to a unusual form (when compared to the initial one). We also state that, under some assumptions on the roughness patterns, the difficulties vanish, leading to a well-posed homogenized problem. A numerical simulation evidences the behavior of the solution: although the pressure tends to a smooth one, the saturation oscillations are not damped. This does not prevent from defining an equivalent homogenized saturation but only points out the anisotropic effects on the saturation function in cavitated areas

School System Evaluation By Value-Added Analysis under Endogeneity

Value-added analysis is a common tool in analysing school performances. In this paper, we analyse the SIMCE panel data which provides individual scores of about 200,000 students in Chile, and whose aim is to rank schools according to their educational achievement. Based on the data collection procedure and on empirical evidences, we argue that the exogeneity of some covariates is questionable. This means that a nonvanishing correlation appears between the school-specific effect and some covariates. We show the impact of this phenomenon on the calculation of the value-added and on the ranking, and provide an estimation method that is based on instrumental variables in order to correct the bias of endogeneity. Revisiting the definition of the value-added, we propose a new calculation robust to endogeneity that we illustrate on the SIMCE data.

School system evaluation by value-added analysis under endogeneity

Value-added analysis is a common tool in analysing school performances. In this paper, we analyse the SIMCE panel data which provides individual scores of about 200,000 students in Chile, and whose aim is to rank schools according to their educational achievement. Based on the data collection procedure and on empirical evidences, we argue that the exogeneity of some covariates is questionable. This means that a nonvanishing correlation appears between the school-specific effect and some covariates. We show the impact of this phenomenon on the calculation of the value-added and on the ranking, and provide an estimation method that is based on instrumental variables in order to correct the bias of endogeneity. Revisiting the definition of the value-added, we propose a new calculation robust to endogeneity that we illustrate on the SIMCE data.value-added, school effectiveness, multilevel model, endogeneity, instrumental variables

Le cadre juridique régissant la relation entre le chercheur et le sujet de recherche : la sécurité conférée par le droit canadien et le droit québécois est-elle illusoire ?

Le présent article propose une revue du cadre normatif québécois régissant la relation chercheur-sujet de recherche. Après l’examen des sources des obligations du chercheur en droit québécois, les auteurs procèdent à la nomenclature de ces dernières. Puis ils tentent de démontrer que, malgré la reconnaissance et l’intégration des règles de bioéthique au corpus juridique québécois, l’encadrement normatif de la recherche au Québec, tout comme au Canada, laisse voir des lacunes importantes quant à la protection des droits des sujets de recherche. Ces lacunes sont issues principalement de l’application des règles en droit québécois, du rôle joué par les comités d’éthique de la recherche et par les organismes d’inspection de la recherche et de l’activité professionnelle des chercheurs. Les auteurs soutiennent que la sécurité des sujets de recherche conférée par le droit québécois et le droit canadien est en fait illusoire, cette sécurité étant à l’heure actuelle principalement attribuable à la bonne foi des acteurs engagés dans le domaine de la recherche.This paper proposes an overview of the Québec normative framework governing the relationship in research projects between researcher and subject. Following an examination of the sources of researchers’ obligations under Québec law, the authors regroup them into three broad categories. Then, they attempt to demonstrate how it is that despite the recognition and integration of bioethical rules into Québec legal doctrine, the normative framework for research in Québec, as in Canada, is exposed to significant gaps regarding the protection of the rights of research subjects. These gaps stem mainly from the application of the rules under Québec law, plus the role assumed by ethical research committees and by organizations that supervise research and researchers’ professional activities. The authors maintain that the security of research subjects granted by Québec and Canadian legal sources is in fact misleading since at present such security is mainly due to the good will of those involved in performing the research