Export Restraints and Horizontal Product Differentiation

We consider the effects of export restraints on price competition in the Hotelling model of horizontal differentiation. We characterize the Nash equilibrium for all possible values of the quota and compare our results with those of Krishna (89). We show that a foreign producer would choose a VER in the vicinity of the Free Trade Equilibrium. In order to maximize domestic welfare, a government would necessarily choose complete protectionism nor Free Trade.Hotelling; optimal quota; price competition

Asymmetries of information in centralized order-driven markets

We study the efficiency of the equilibrium price in a centralized, order-driven market where many asymmetrically informed traders are active for many periods. We show that asymmetries of information can lead to sub-optimal information revelation with respect to the symmetric case. In particular, we assess that the more precise the information the higher the incentive to reveal it, and that the value of private information is related to the volume of exogenous trade present on the market. Moreover, we prove that any informed trader, whatever his information, reveals his private signal during an active phase of the market, concluding that long pre-opening phases are not effective as an information discovering device in the presence of strategic players.Asymmetric information; pre-opening; insider trading

The Hotelling Model with Capacity Precommitment

We consider the two-stage game proposed by Kreps and Scheinkman (83) in the address-model of horizontal differentiation developed by Hotelling. Firms choose capacities in the first stage and then compete in prices. We show that price competition is drastically softened since in almost all subgame perfect equilibria firms behave as if they were an integrated monopolist i.e., they choose capacities which exactly cover the market, so that there is no room for price competition. If furthermore the installation cost for capacity is one fourth of the transportation or more, this result stands for all SPE. Like Kreps and Scheinkman, we show that the Cournot allocations coincide with the SPE allocations of our game form. Finally, our analysis provides an interesting treatment of mixed strategy equilibria which is quite new in the literature.Hotelling; capacity; price competition

Steroid profiling by UHPLC-MS/MS in dried blood spots collected from healthy women with and without testosterone gel administration.

The quantification of a large panel of endogenous steroids in serum by LC-MS/MS represents a powerful clinical tool for the screening or diagnosis of diverse endocrine disorders. This approach has also demonstrated excellent sensitivity for the detection of testosterone misuse in the anti-doping field, especially in female athlete population. In both situations, the use of dried blood spots (DBS) could provide a viable alternative to invasive venous blood collection. Here, the evaluation of DBS sampling for the quantification of a panel of endogenous steroids using UHPLC-MS/MS is described. The UHPLC-MS/MS method was validated for quantitative analysis of eleven free and eight conjugated steroids and was then used for the analysis of DBS samples collected in 14 healthy women during a normal menstrual cycle (control phase) followed by a 28-days testosterone gel treatment (treatment phase). Results were compared with those obtained from serum matrix. Satisfactory performance was obtained for all compounds in terms of selectivity, linearity, accuracy, precision, combined uncertainty, stability as well as extraction recovery and matrix effects. In control phase, high correlation was observed between DBS and serum concentrations for most compounds. In treatment phase, higher testosterone concentrations were observed in capillary than in venous DBS, suggesting a possible interference resulting from testosterone contamination on finger(s) used for gel application. Steroid profiling in capillary DBS represents a simple and efficient strategy for monitoring endogenous steroid concentrations and their fluctuation in clinical context of steroid-related disorders, or for the detection of testosterone abuse in anti-doping

Straightforward quantification of endogenous steroids with liquid chromatography-tandem mass spectrometry: Comparing calibration approaches.

Different calibration strategies are used in liquid chromatography hyphenated to mass spectrometry (LC-MS) bioanalysis. Currently, the surrogate matrix and surrogate analyte represent the most widely used approaches to compensate for the lack of analyte-free matrices in endogenous compounds quantification. In this context, there is a growing interest in rationalizing and simplifying quantitative analysis using a one-point concentration level of stable isotope-labeled (SIL) standards as surrogate calibrants. Accordingly, an internal calibration (IC) can be applied when the instrument response is translated into analyte concentration via the analyte-to-SIL ratio performed directly in the study sample. Since SILs are generally used as internal standards to normalize variability between authentic study sample matrix and surrogate matrix used for the calibration, IC can be calculated even if the calibration protocol was achieved for an external calibration (EC). In this study, a complete dataset of a published and fully validated method to quantify an extended steroid profile in serum was recomputed by adapting the role of SIL internal standards as surrogate calibrants. Using the validation samples, the quantitative performances for IC were comparable with the original method, showing acceptable trueness (79%-115%) and precision (0.8%-11.8%) for the 21 detected steroids. The IC methodology was then applied to human serum samples (n = 51) from healthy women and women diagnosed with mild hyperandrogenism, showing high agreement (R <sup>2</sup> > 0.98) with the concentrations obtained using the conventional quantification based on EC. For IC, Passing-Bablok regression showed proportional biases between -15.0% and 11.3% for all quantified steroids, with an average difference of -5.8% compared to EC. These results highlight the reliability and the advantages of implementing IC in clinical laboratories routine to simplify quantification in LC-MS bioanalysis, especially when a large panel of analytes is monitored

High-resolution mass spectrometry as an alternative detection method to tandem mass spectrometry for the analysis of endogenous steroids in serum.

Recently, steroid hormones quantification in blood showed a promising ability to detect testosterone doping and interesting complementarities with the urinary module of the Athlete Biological Passport (ABP). In this work, an ultra-high pressure liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) method was developed for the quantification of eleven endogenous steroids in serum. The performance of the full scan and targeted SIM acquisition modes was evaluated and compared to the performance of tandem mass spectrometry (MS/MS). Passing-Bablok regressions and Bland-Altman plots were assessed for each analyte of interest, and concentration values measured by HRMS showed high correlation with the ones obtained by MS/MS for all target hormones, with low absolute differences in the majority of cases. A slight decrease in terms of sensitivity was observed with HRMS in both acquisition modes, but performing an analysis of variance multiblock orthogonal partial least squares (AMOPLS) on the dataset obtained with all three methods revealed that only 0.8% of the total variance was related to instrumentation and acquisition methods. Moreover, the evaluation of the testosterone administration effect over time highlighted testosterone itself and dihydrotestosterone as the most promising biomarkers of exogenous testosterone administration. This conclusion suggests that HRMS could provide suitable performance for blood steroid analysis in the anti-doping field

An Introduction To The Technology Of Thin Film Silicon Photovoltaics

Several aspects of the science and technology of thin film silicon for photovoltaic applications will be presented. The potential advantages of this technology over crystalline wafer technology will be discussed. A basic understanding of the material properties of thin film silicon layers enables to assess their potential and limitations when used in photovoltaic devices. A brief review of the production technology for thin films will be given with particular emphasis on amorphous and microcrystalline silicon. As for other photovoltaic technologies, the push for higher efficiency of thin film silicon devices is strong. An appealing feature of these materials is that they can be easily integrated in multi-junction tandem devices. For instance, stacking amorphous and microcrystalline silicon thin films in one tandem cell, the micromorph cell, increases the efficiency well above the characteristic values of single junction cells. The Institute of Microengineering (IMT) has been a pioneer in the research and development of thin film silicon photovoltaics over the last 20 years and several latest developments on are reviewed