Modèle macroéconomique de déséquilibre avec délais d’attente

Le but de cet article est de présenter un modèle macroéconomique de déséquilibre dans lequel des ajustements partiels vers l’équilibre peuvent se produire par l’intermédiaire des délais d’attente. Le modèle comporte trois biens : la monnaie, deux biens de consommation substituables et deux agents : un producteur et un consommateur. Dans un premier temps, la dynamique du modèle est indiquée. Puis le calcul des agents économiques, à l’intérieur de chaque période, est décrit. Enfin, la forme réduite du modèle et les conditions d’unicité d’équilibre sont données.The purpose of this paper is to present a macro-disequilibrium model in which some partial adjustments towards equilibrium can happen by means of waiting delays. We consider an economy with three commodities: money, two commodities which are substituable and two agents: a consumer and a producer. At first, the dynamics of this model is given. Then the agents' behaviors are explained. At last, the reduced form of this model and the conditions for uniqueness are provided

The use of an e-learning constructivist solution in workplace learning

We wished to investigate whether an e-learning approach which uses constructivist principles can be successfully applied to train employees in a highly specialised skill thought to require expert individuals and extensive prolonged training. The approach involved the development of an e-learning package which included simulations and interactivity, then experimental testing in a case study workplace environment with the collection of both quantitative and qualitative data to assess the effectiveness of the package. Our study shows that this e-learning strategy improved the skills of the inexperienced operator significantly. We therefore propose that such programmes could be used as a work based training aid and used as a model system for the training of employees in complex skilled tasks in the workplace. This research demonstrates that the e-learning can be applied outside the traditional learning environment to train unskilled employees to undertake complex practical tasks which traditionally would involve prohibitively expensive instruction. This work also illustrates that simulations and interactivity are powerful tools in the design of successful e-learning packages in preparing learners for real world practical situations. Finally this study shows that workplace learners can be better served by elearning environments rather than conventional training as they allow asynchronous learning and private study which are valued by employees who have other demands on their time and are more comfortable receiving tuition privately Relevance to industry: E-learning using constructivist principles, and incorporating simulations and interactivity can be used successfully in the training of highly specialised and skilled tasks required in the modern workplace

Modèle macroéconomique de déséquilibre avec délais d’attente

The purpose of this paper is to present a macro-disequilibrium model in which some partial adjustments towards equilibrium can happen by means of waiting delays. We consider an economy with three commodities: money, two commodities which are substituable and two agents: a consumer and a producer. At first, the dynamics of this model is given. Then the agents' behaviors are explained. At last, the reduced form of this model and the conditions for uniqueness are provided. Le but de cet article est de présenter un modèle macroéconomique de déséquilibre dans lequel des ajustements partiels vers l’équilibre peuvent se produire par l’intermédiaire des délais d’attente. Le modèle comporte trois biens : la monnaie, deux biens de consommation substituables et deux agents : un producteur et un consommateur. Dans un premier temps, la dynamique du modèle est indiquée. Puis le calcul des agents économiques, à l’intérieur de chaque période, est décrit. Enfin, la forme réduite du modèle et les conditions d’unicité d’équilibre sont données.

Chromosomal control of pig populations in France: 2002-2006 survey

The chromosomal control of pig populations has been widely developed in France over the last ten years. By December 31st, 2006, 13 765 individuals had been karyotyped in our laboratory, 62% of these since 2002. Ninety percent were young purebred boars controlled before service in artificial insemination centres, and 3% were hypoprolific boars. So far, 102 constitutional structural chromosomal rearrangements (67 since 2002) have been described. Fifty-six were reciprocal translocations and 8 peri- or paracentric inversions. For the first time since the beginning of the programme and after more than 11 000 pigs had been karyotyped, one Robertsonian translocation was identified in 2005 and two others in 2006. The estimated prevalence of balanced structural chromosomal rearrangements in a sample of more than 7700 young boars controlled before service was 0.47%. Twenty-one of the 67 rearrangements described since 2002 were identified in hypoprolific boars. All were reciprocal translocations. Twelve mosaics (XX/XY in 11 individuals, XY/XXY in one individual) were also diagnosed. Two corresponded to hypoprolific boars, and three to intersexed animals. The results presented in this communication would justify an intensification of the chromosomal control of French and, on a broader scale, European and North-American pig populations

Utilisation de la grille pour la simulation de température de brillance dans une atmosphère nuageuse composée de cirrus

Utilisation de la grille pour la simulation de température de brillance dans une atmosphère nuageuse composée de cirru

Application de la grille à la télédétection des aérosols

International audienceLes satellites sont devenus des instruments incontournables de l'observation de la Terre et de son atmosphère. Ils permettent de suivre et de caractériser de plus en plus finement, à l'échelle globale, les différents constituants de l'atmosphère (gaz, nuages, aérosols) qui seront ensuite pris en compte dans les modèles de prévision du climat. Un corollaire à l'accroissement du volume d'informations émis par satellite et au raffinement des techniques de modélisation est l'augmentation de la puissance de calcul nécessaire à l'exploitation scientifique des données. Dans cette perspec- tive, l'Initiative de Grille Européenne (EGI, anciennement EGEE) est une solution envisagée pour traiter des données satellitaires. Elle a été appliquée au traitement des données d'un satellite français d'observation des nuages et des aérosols, PARA- SOL, et a permis de traiter en trois mois et sans frais de développement important, en particulier sans achat de nouveau matériel ni refonte de l'application concernée, l'équivalent de dix-huit mois de la puissance de calcul obtenue en mobilisant toutes les ressources à la disposition du personnel exploitant - ce qui n'aurait de toute façon pas été effectué dans ces conditions

Changes in corticospinal transmission following 8 weeks of ankle joint immobilization

Joint immobilization has previously been shown to modulate corticospinal excitability. The present study investigated changes in the excitability of distinct fractions of the corticospinal pathway by means of conditioning the H-reflex with transcranial magnetic stimulation (TMS) of the primary motor cortex (Hcond). This method allows assessment of transmission in fast (monosynaptic) and slow(er) (polysynaptic) corticospinal pathways.Methods: 9 subjects underwent 8 weeks of unilateral ankle joint immobilization during daytime, 7 subjects served as controls. The measures obtained before and after immobilization included stretch- and H-reflexes assessing excitability of the spinal reflex circuitries, TMS recruitment curves estimating overall changes in corticospinal excitability, and Hcond.Results: TMS recruitment curves showed an overall increase in corticospinal excitability following immobilization. Importantly, Hcond revealed significant facilitation of conditioned reflexes, but only for longer conditioning intervals, suggesting that immobilization increased excitability only of slower, indirect corticospinal pathways. No changes were observed in the control group. Immobilization had no significant effects on spinal reflex measures.Conclusions: 8 weeks of ankle joint immobilization was accompanied by pathway-specific modulation of corticospinal transmission.Significance: It is particularly interesting that fast corticospinal projections were unaffected as these are involved in controlling many, if not most, movements in humans

The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days of muscle unloading

In the light of the dynamic nature of habitual plantar flexor activity, we utilized an incremental isokinetic exercise test (IIET) to assess the work-related power deficit (WoRPD) as a measure for exercise-induced muscle fatigue before and after prolonged calf muscle unloading and in relation to arterial blood flow and muscle perfusion. Eleven male subjects (31 ± 6 years) wore the HEPHAISTOS unloading orthosis unilaterally for 56 days. It allows habitual ambulation while greatly reducing plantar flexor activity and torque production. Endpoint measurements encompassed arterial blood flow, measured in the femoral artery using Doppler ultrasound, oxygenation of the soleus muscle assessed by near-infrared spectroscopy, lactate concentrations determined in capillary blood and muscle activity using soleus muscle surface electromyography. Furthermore, soleus muscle biopsies were taken to investigate morphological muscle changes. After the intervention, maximal isokinetic torque was reduced by 23·4 ± 8·2% (P<0·001) and soleus fibre size was reduced by 8·5 ± 13% (P = 0·016). However, WoRPD remained unaffected as indicated by an unchanged loss of relative plantar flexor power between pre- and postexperiments (P = 0·88). Blood flow, tissue oxygenation, lactate concentrations and EMG median frequency kinematics during the exercise test were comparable before and after the intervention, whereas the increase of RMS in response to IIET was less following the intervention (P = 0·03). In conclusion, following submaximal isokinetic muscle work exercise-induced muscle fatigue is unaffected after prolonged local muscle unloading. The observation that arterial blood flow was maintained may underlie the unchanged fatigability