Idiosyncratic uncertainty, capacity utilization and the business cycle

In a stochastic dynamic general equilibrium framework, we introduce the concept of variable capacity utilization (as opposed to the concept of capital utilization). We consider an economy where imperfectly competitive firms use a putty-clay technology and decide on their productive capacity level under uncertainty. An idiosyncratic uncertainty about the exact position of the demand curve facedby each firm explains why sorne productive capacities may remain idle in the sequel and why individual capacity utilization rates differ across firms. The capacity underutilization at the aggregate level thus hides a diversity of microeconomic situations. The variability of the capacity utilization allows for a good description of sorne of the main stylized facts of the business cycle, propagates and magnifies aggregate technological shocks and generates endogenous persistence (Le., the output growth rate displays positive serial correlation)

Idiosyncratic uncertainty, capacity utilization and the business cycle.

In a stochastic dynamic general equilibrium framework, we introduce the concept of variable capacity utilization (as opposed to the concept of capital utilization). We consider an economy where imperfectly competitive firms use a putty-clay technology and decide on their productive capacity level under uncertainty. An idiosyncratic uncertainty about the exact position of the demand curve facedby each firm explains why sorne productive capacities may remain idle in the sequel and why individual capacity utilization rates differ across firms. The capacity underutilization at the aggregate level thus hides a diversity of microeconomic situations. The variability of the capacity utilization allows for a good description of sorne of the main stylized facts of the business cycle, propagates and magnifies aggregate technological shocks and generates endogenous persistence (Le., the output growth rate displays positive serial correlation).Business Cycle; Capacity Utilization; Idiosyncratic shocks; Mark-ups; Propagation Mecanism;

Toward a soft image watermarking

This paper introduces a new approach of watermarking for copyright protection. The goal of the method is to hide signatures composed of w segments of r bits in digital images. The framework itself is founded upon a wavelet transformed domain, and an additive embedding rule using products of orthogonal basis functions. We will show how the choice of different kinds of orthogonal functions allows to improve the robustness of the watermarking scheme to signal processing or geometric attacks.Cet article introduit une nouvelle méthode de tatouage pour la protection d'images fixes. La méthode permet de cacher une signature dans une image, sous la forme de w paquets de r bits. Le schéma de tatouage est additif, et la marque elle-même est calculée par addition de produits de couples de fonctions orthogonales. Nous montrerons comment le choix des fonctions orthogonales peut être fait, de façon à rendre le tatouage robuste face à différents types d'attaques. Puis, nous donnerons quelques résultats permettant d'apprécier la robustesse du tatouage, et discuterons des améliorations possibles pouvant être apportées à une telle méthode

A game theory view of military conflict in the Taiwan strait

The article of record as published may be found at https://doi.org/10.1080/147517903200014941

The access deterrence scenario: A new approach to assessing national missile defenses

The article of record as published may be found at https://doi.org/10.1080/1475179022000233

New regime of droplet generation in a T-shape microfluidic junction

International audienceWe present an experimental study of a new regime of monodisperse micro-droplet generation that we named the balloon regime. A dispersion of oil in water in a T-junction microfluidic system was studied. Several microfluidic devices having different cross-sections of the continuous and the dispersed phases micro-channels were tested. This new regime appears only for low- dispersed phase velocity. The micro-droplet size is mainly related to the geometry of the T-junction micro-channels especially its width and depth, and independent of the continuous and dispersed phases velocities. In our experiments, the velocities of the continuous and the dispersed phases vc and vd respectively, have been varied in a wide range: vc from 0.5 to 500 mm/s, and vd from 0.01 to 30 mm/s. We show that the continuous phase only controls the micro-droplet density, while the dispersed phase linearly changes the frequency of the micro-droplet generation. Another particularity of the present regime, which differentiates it from all other known regimes, is that the micro-droplet retains its circular shape throughout its formation at the T junction, and undergoes no deformation due to the drag forces. We propose a mechanism to explain the formation of microdroplets in this new regime

MRI Gastric Images Processing using a Multiobjective Fly Algorithm

In this study, we combine computer vision and visualisation/data exploration to analyse magnetic resonance imaging (MRI) data and detect garden peas inside the stomach. It is a preliminary objective of a larger project that aims to understand the kinetics of gastric emptying. We propose to perform the image analysis task as a multi-objective optimisation. A set of 7 equally important objectives are proposed to characterise peas. We rely on a cooperation co-evolution algorithm called 'Fly Algorithm' implemented using NSGA-II. The Fly Algorithm is a specific case of the 'Parisian Approach' where the solution of an optimisation problem is represented as a set of individuals (e.g. the whole population) instead of a single individual (the best one) as in typical evolutionary algorithms (EAs). NSGA-II is a popular EA used to solve multi-objective optimisation problems. The output of the optimisation is a succession of datasets that progressively approximate the Pareto front, which needs to be understood and explored by the end-user. Using interactive Information Visualisation (InfoVis) and clustering techniques, peas are then semi-automatically segmented

An insight into immunogenic salivary proteins of Anopheles gambiae in African children

<p>Abstract</p> <p>Background</p> <p>During blood feeding, the mosquito injects saliva into the vertebrate host. This saliva contains bioactive components which may play a role in pathogen transmission and in host-vector relationships by inducing an immune response in the vertebrate host. The evaluation of human immune responses to arthropod bites might also represent a research direction for assessing individual exposure to the bite of a malaria vector.</p> <p>Methods</p> <p>The present study examined the antibody (Ab) IgG response during the season of exposure to <it>Anopheles gambiae </it>bites in young children living in a malaria endemic area. Immunoblots were performed with <it>An. gambiae </it>saliva to detect anti-saliva Ab bands and the evolution of immunogenic bands at the peak of, and following, the transmission period.</p> <p>Results</p> <p>The results showed that anti-<it>Anopheles </it>Ab was directed against a limited number of salivary proteins (175, 115, 72 and 30 kDa bands). Specific IgG responses to mosquito salivary proteins were variable among exposed individuals; nevertheless, two major bands (175 and 72 kDa) were observed in all immune-responder children. Analysis of the intensity of immunogenic bands revealed that IgG levels against the 175 kDa band were significantly higher during the peak period compared to the end period malaria transmission.</p> <p>Conclusion</p> <p>This preliminary work supports the potential of using anti-saliva immune responses as a measure of exposure to <it>Anopheles </it>bites. The use of immunoblots coupled with evaluation of band intensity could be an adequate tool for distinguishing immunogenic salivary proteins as candidate markers of bite exposure. Furthermore, this study may open the way to design new epidemiological tools for evaluating the risk of malaria exposure.</p

Kv4 potassium channels modulate hippocampal EPSP-spike potentiation and spatial memory in rats

International audienceKv4 channels regulate the backpropagation of action potentials (b-AP) and have been implicated in the modulation of longterm potentiation (LTP). Here we showed that blockade of Kv4 channels by the scorpion toxin AmmTX3 impaired reference memory in a radial maze task. In vivo, AmmTX3 intracerebroventricular (i.c.v.) infusion increased and stabilized the EPSP-spike (E-S) component of LTP in the dentate gyrus (DG), with no effect on basal transmission or short-term plasticity. This increase in E-S potentiation duration could result from the combination of an increase in excitability of DG granular cells with a reduction of GABAergic inhibition, leading to a strong reduction of input specificity. Radioactive in situ hybridization (ISH) was used to evaluate the amounts of Kv4.2 and Kv4.3 mRNA in brain structures at different stages of a spatial learning task in naive, pseudoconditioned, and conditioned rats. Significant differences in Kv4.2 and Kv4.3 mRNA levels were observed between conditioned and pseudoconditioned rats. Kv4.2 and Kv4.3 mRNA levels were transiently up-regulated in the striatum, nucleus accumbens, retrosplenial, and cingulate cortices during early stages of learning, suggesting an involvement in the switch from egocentric to allocentric strategies. Spatial learning performance was positively correlated with the levels of Kv4.2 and Kv4.3 mRNAs in several of these brain structures. Altogether our findings suggestthat Kv4 channels could increase the signal-to-noise ratio during information acquisition, thereby allowing a better encoding of the memory trace

Modelling molecular networks: relationships between different formalisms and levels of details

This document is the deliverable 1.3 of French ANR CALAMAR. It presents a study of different formalisms used for modelling and analyzing large molecular regulation networks, their formal links, in terms of mutual encodings and of abstractions, and the corresponding levels of detail captured