Le multiplicateur de crédit généralisé : un modèle probabiliste

A generalized credit multiplier: A Markovian model The coefficient referred to by the name of credit multiplier makes it possible to work ouf thé additional amount of crédit which is to appear following the additional injection of high-powered money info an economy. The way this coefficient is traditionally arrived at makes it necessary that one should accept to simplify reality in more than one point. On the one hand on considers only one category of financial intermediaries, thus deliberately ignoring the fact that every one of them does mot get equally easy terms and is not subject to the same obligations. On the other hand on does not allow for the fact that credits rotate at perceptibly varying speeds, according to the category they belong to, as some of the financial intermediaries consider keeping part of their reserves available. This paper is aimed at showing that the formula for the multiplier can be derived through the medium of a probability model. Thus proceeding, it will be possible, without any objections to be raised, to dismiss simplifying theories. Consequently formula can be worked out which makes it possible to get closer reality as well as to assess more accurately the effects of some possible injection of money in the economy.Par « multiplicateur de crédit », on entend un coefficient permettant de calculer le supplément de crédit résultant de l'insertion, dans une économie, d'un supplé­ment de monnaie centrale. Mais dans l'établissement de la formule traditionnelle, on ne fait aucun cas de la diversité des intermédiaires financiers qui sont loin d'être soumis tous aux mêmes obligations. On ne fait aucun cas non plus des différences existant, en pratique, dans les vitesses de rotation des différents types de crédit. L'objet du papier est double : d'abord montrer que l'on peut, à l'aide d'un modèle probabiliste s'appuyant sur la théorie des chaînes de Markov, retrouver d'une autre manière la formule traditionnelle du multiplicateur ; ensuite montrer que la théorie des processus markoviens permet de généraliser, par étapes, cette formule en renonçant aux hypothèses abusivement simplificatrices que nous avons rappelées. On aboutit ainsi à une formule permettant de serrer la réalité de plus près et d'estimer plus exactement les conséquences d'une insertion éventuelle de monnaie dans l'économie.Marchal Jean, Poulon Frédéric. Le multiplicateur de crédit généralisé : un modèle probabiliste. In: Revue économique, volume 27, n°2, 1976. pp. 200-232

Réponse de Jean Marchal et Frédéric Poulon

Marchal Jean, Poulon Frédéric. Réponse de Jean Marchal et Frédéric Poulon. In: Revue économique, volume 28, n°4, 1977. pp. 643-650

Réponse de Jean Marchal et Frédéric Poulon

Marchal Jean, Poulon Frédéric. Réponse de Jean Marchal et Frédéric Poulon. In: Revue économique, volume 28, n°4, 1977. pp. 643-650

Ferritic and martensitic ODS steel resistance upset welding of fuel claddings: Weldability assessment and metallurgical effects

Development and characterization of clad-to-plug resistance upset welds is presented for two oxide dispersion strengthened steels candidates for sodium-cooled fast reactors fuel cladding: 9Cr ferrito-martensitic steel and 14Cr ferritic steel. A comparative approach is adopted regarding these two materials implying weldability studies and weld mechanical strength tests. A special attention is paid on welding metallurgical effects on the specific microstructure of these materials. Among others, some major grain property modifications by dynamic recrystallization and a slight modification of precipitate sizes and volume fraction are found and discussed

In-situ fiber drawing induced synthesis of silver-tellurium semiconductor compounds

We examine the thermal drawing of zinc tellurite silver-containing glass. While the silver-doped glass fibers remain unchanged over thermal drawing under oxygenatmosphere, we establish that under argon silver doping leads to the growth of a thin, metallic-like precipitate at the fiber surface. Optical, chemical and structural analysis, supported by UV–vis, HR-TEM and XPS, reveals that the precipitate contains silver telluride nanoparticles in its first tens-of-nanometers. We believe the direct fiber-drawing induced synthesis of silver telluride semiconductor compounds could lead to development of new fiber-based devices, with applications spanning photonics or sensing

Optical Signatures Derived From Deep UV to NIR Excitation Discriminates Healthy Samples From Low and High Grades Glioma

International audienceAmong all the tumors of the central nervous system (CNS), glioma are the most deadly and the most malignant. Surgical resection is the standard therapeutic method to treat this type of brain cancer. But the diffusive character of these tumors create many problems for surgeons during the operation. In fact, these tumors migrate outside the tumor solid zone and invade the surrounding healthy tissues. These infiltrative tissues have the same visual appearance as healthy tissues, making it very difficult for surgeons to distinguish the healthy ones from the diffused ones. The surgeon, therefore, cannot properly remove the tumor margins increasing the recurrence risk of the tumor. To resolve this problem, our team has developed a multimodal two-photon fibered endomicroscope, compatible with the surgeon trocar, to better delimitate tumor boundaries by relying on the endogenous fluorescence of brain tissues. In this context, and in order to characterize the optical signature of glioma tumors, this study offers multimodal and multi-scaled optical measurements from healthy tissues to high grade glioma. We can interrogate tissue from deep ultra-violet to near infrared excitation by working with spectroscopy, fluorescence lifetime imaging, two-photon fluorescene imaging and Second Harmonic Generation (SHG) imaging. Optically derived ratios such as the Tryptophan/Collagen ratio, the optical redox ratio and the long lifetime intensity fraction, discriminated diseased tissue from its normal counterparts when fitted by Gaussian ellipsoids and choosing a threshold for each. Additionally two-photon fluorescence and SHG images were shown to display similar histological features as Hematoxylin-Eosin stained images

Alloying-element interactions with austenite/martensite interface during quenching and partitioning of a model Fe-C-Mn-Si alloy

The alloying elements partitioning from martensite to austenite during quenching and partitioning was analysed by coupling in situ High Energy X-Ray Diffraction experiments and 3D atom probe tomography. A rapid and significant carbon partitioning from martensite to austenite without any partitioning of both Mn and Si was highlighted while the interface was immobile. After a relatively short time at 400 °C, a clear Mn partitioning occurs at the vicinity of the α′/γ interface. The analysis conducted indicates that manganese equilibrates its chemical potential during partitioning and raises the issue of the Constrained Carbon Equilibrium model applicability throughout the partitioning process.Partition du carbone dans les phases ferritiques nanostructurées: cinétiques et microstructure

Alloying-element interactions with austenite/martensite interface during quenching and partitioning of a model Fe-C-Mn-Si alloy

International audienceThe alloying elements partitioning from martensite to austenite during quenching and partitioning was analysed by coupling in situ High Energy X-Ray Diffraction experiments and 3D atom probe tomography. A rapid and significant carbon partitioning from martensite to austenite without any partitioning of both Mn and Si was highlighted while the interface was immobile. After a relatively short time at 400 °C, a clear Mn partitioning occurs at the vicinity of the α′/γ interface. The analysis conducted indicates that manganese equilibrates its chemical potential during partitioning and raises the issue of the Constrained Carbon Equilibrium model applicability throughout the partitioning process