Effects of Alcohol on the Acquisition and Expression of Fear Potentiated Startle in Mouse Lines Selectively Bred for High and Low Alcohol Preference

Rationale: Anxiety disorders and alcohol-use disorders frequently co-occur in humans perhaps because alcohol relieves anxiety. Studies in humans and rats indicate that alcohol may have greater anxiolytic effects in organisms with increased genetic propensity for high alcohol consumption. Objectives and Methods: The purpose of this study was to investigate the effects of moderate doses of alcohol (0.5, 1.0, 1.5 g/kg) on the acquisition and expression of anxiety-related behavior using a fear-potentiated startle (FPS) procedure. Experiments were conducted in two replicate pairs of mouse lines selectively bred for high- (HAP1 and HAP2) and low- (LAP1 and LAP2) alcohol preference; these lines have previously shown a genetic correlation between alcohol preference and FPS (HAP\u3eLAP; Barrenha and Chester 2007). In a control experiment, the effect of diazepam (4.0 mg/kg) on the expression of FPS was tested in HAP2 and LAP2 mice. Results: The 1.5 g/kg alcohol dose moderately decreased the expression of FPS in both HAP lines but not LAP lines. Alcohol had no effect on the acquisition of FPS in any line. Diazepam reduced FPS to a similar extent in both HAP2 and LAP2 mice. Conclusions: HAP mice may be more sensitive to the anxiolytic effects of alcohol than LAP mice when alcohol is given prior to the expression of FPS. These data collected in two pairs of HAP/LAP mouse lines suggest that the anxiolytic response to alcohol in HAP mice may be genetically correlated with their propensity toward high alcohol preference and robust FPS

Fixed and random effects models: making an informed choice

This paper assesses the options available to researchers analysing multilevel (including longitudinal) data, with the aim of supporting good methodological decision-making. Given the confusion in the literature about the key properties of fixed and random effects (FE and RE) models, we present these models’ capabilities and limitations. We also discuss the within-between RE model, sometimes misleadingly labelled a ‘hybrid’ model, showing that it is the most general of the three, with all the strengths of the other two. As such, and because it allows for important extensions—notably random slopes—we argue it should be used (as a starting point at least) in all multilevel analyses. We develop the argument through simulations, evaluating how these models cope with some likely mis-specifications. These simulations reveal that (1) failing to include random slopes can generate anti-conservative standard errors, and (2) assuming random intercepts are Normally distributed, when they are not, introduces only modest biases. These results strengthen the case for the use of, and need for, these models

Evaluate public transport governance: should urban authorities contract with one or several operators ?

In France, 90% of the urban authorities use to delegate the production of public transport services to a single operator. And the last 10% carry on a direct management (régie municipale). The coexistence of several operators is very uncommon, while several European cities work with more than one partner. Those local authorities (London, Stockholm…) have chosen a geographical fragmentation, an horizontal separation, or a vertical disintegration. It is never the case in France. At the same time, we observed a strong concentration of the sector in France (the three main groups hold 75% of market share) for 20 years. The number of bidders is now dramatically low for an usual call for tender. Competition is lifeless, and most of the commentators do not predict an improvement in the future. In order to increase competitive pressure, one of the possibility is to divide the big networks into attractive and accessible parts. This option is already tested in Europe and seems to have several advantages. The purpose of this paper is to present an evaluation of the benefits and costs of such a fragmentation. Firstly, we estimate a cost function in order to obtain an econometric measure of the economies of scale and scope in the public transport industry. In this aim, we ran a panel data provided by the CERTU (ministerial agency), that gathers the large results of an annual survey between 1995 and 2002. We opted for a translog specification with several control variables. Secondly, we present the main determinants of the transaction costs and the gains associated with more competition within the sector. Those two groups of costs and benefits are more globally evaluated, according to the data available