Issues on the Measurement of the Solow Residual and the Testing of its Exogeneity: a Tale of Two Countries

Using aggregate US and Canadian data, this paper examines the implications for the empirical assessment of market structure and exogeneity of productivity shocks of correcting the Solow residual for variation in capacity utilization. In contrast to most studies, not accounting for capacity utilization, our results suggest that the US and Canadian market structures are well described by constant returns to scale and perfect competition. They also suggest that Canadian productivity shocks are exogenous to real and monetary variables, while US productivity shocks become exogenous to narrowly-defined monetary aggregates and monetary policy innovations when the capital stock is adjusted for variations in utilization rates. À l'aide de données agrégées américaines et canadiennes, nous examinons les implications empiriques quant à la structure de marché et à l'exogénéité des chocs de productivité, suite à la correction de la mesure du résidu de Solow lorsqu'il y a utilisation variable du capital. Comparativement, à la plupart des études qui ont ignoré cette considération, nos résultats suggèrent qu'en agrégé, les structures de marché canadienne et américaine sont convenablement caractérisées par des rendements constants à l'échelle et la concurrence parfaite. Nous trouvons aussi qu'après ajustement pour un taux variable d'utilisation du stock de capital, la mesure corrigée des chocs de productivité canadiens est exogène aux variables monétaires et réelles, alors que celle des chocs de productivité américains devient exogène aux agrégats monétaires étroits et aux innovations monétaires.Solow residuals; exogeneity; productivity shocks; market structure; varying capacity utilization

Product ecolabelling, competition and the environment

The paper explores the impact of a third-party product ecolabel (i.e. green label) on competition and the environment, and the firms' strategies during the negotiation of the minimum environmental requirements underlying a product's eligibility for the ecolabel. The introduction includes some empirical observation about the development of the European ecolabel. The second part presents the model. We assume Cournot competition in a homogenous industry made up of multi-product firms each selling the whole range of product-variants, from green to brown. Green consumers "trust" the ecolabel. We derive demand, supply, prices and profits at the equilibrium before and after ecolabel. We first assume that firms do not innovate on their products. We then introduce environmental innovation into the model. The third part analyses the impact of the ecolabel on competition (firms' profits) and the environment (green innovation and market shares). The conclusion contrasts the results with the ones obtained in the case of a heterogeneous industry - i.e., an industry made up of mono-product firms each selling a product having an environmental profile different than that of the other firms' products- and draws policy considerations. The paper expands the literature on product ecolabelling by considering imperfect competition, giving thus the possibility for the firms to undertake green innovations affecting non marginal costs, and by taking into account the type of industry concerned by the ecolabel. We find that firms in a homogenous industry are better off with an ecolabel than without and might even be willing to adopt environmentally effective criteria if the green demand is important and innovation costs are low. This contrasts with results obtained in a previous paper for a heterogeneous industry, in which part of the firms will always lose from the implementation of an environmentally effective ecolabel and oppose its development. Cross-industry comparison suggests that regulators should start developing ecolabelling programs with homogenous industry in which innovation costs are likely to be negligible as compared to the costs of production

On the significance of B-decays to radially excited D

We discuss the possibilities of testing the recent claims of a relatively large value of the B --> D' transition form factor through B0--> D' pi+ and B- --> D' pi- decay modes. To estimate the width of the latter we need the decay constant of the radially excited D-meson that we computed in lattice QCD with Nf=2 dynamical flavors and after taking the continuum limit we found f(D')=117(25) MeV. We also provide an update for the values of the D-meson decay constants obtained by using maximally twisted mass QCD.Comment: 16 pages including 5 tables and 3 figures [published version

Vitreous silica distends in helium gas: acoustic vs. static compressibilities

Sound velocities of vitreous silica are measured under He compression in the pressure range 0-6 GPa by Brillouin light scattering. It is found that the well-known anomalous maximum in the pressure dependence of the compressibility is suppressed by He incorporation into the silica network. This shows that the elastic anomaly relates to the collapse of the largest interstitial voids in the structure. The huge difference between the static and the acoustic compressibilities indicates that the amount of incorporated helium still increases at 6 GPa.Comment: 5 pages, 4 figure

Modeling Modeling Modeling

International audienceModel-driven engineering and model-based approaches have permeated all branches of software engineering to the point that it seems that we are using models, as Molière's Monsieur Jourdain was using prose, without knowing it. At the heart of modeling, there is a relation that we establish to represent something by something else. In this paper we review various definitions of models and relations between them. Then, we define a canonical set of relations that can be used to express various kinds of representation relations and we propose a graphical concrete syntax to represent these relations. We also define a structural definition for this language in the form of a metamodel and a formal interpretation using Prolog. Hence, this paper is a contribution towards a theory of modeling

Branch and Price for a Reliability Oriented DARP Model

Version 1 - Présentation à ISCO 2014We deal here with a static decisional model related to the monitoring of a DARP (Dial and Ride) model which involves, on a closed industrial site, small electrical autonomous vehicles. Because of technological issues, we focus on reliability, and propose a model which assign requests to vehicles while minimizing Load/Unload transactions. We study this model through both a Branch/Price approach, which provides us with benchmarks, and insertion based heuristics, well-fitted to dynamic contexts

CLIC Detector Main Solenoid Design & Status Report

The magnet system for the CLIC Detector concepts is composed of the central solenoid in combination with the two forward anti-solenoids and the ancillary systems necessary for their operation, including the so-called push-pull scenario, allowing the quick exchange of the two detectors on the beam line. An overview of the design parameters of the detector main solenoids is presented hereafter.Comment: LCWS2011, Granada, Spai