Search

Claude Bernard and Louis Pasteur will meet on various occasions, scientific prizes were awarded by Claude Bernard to Louis Pasteur, Claude Bernard's lessons were followed by Louis Pasteur at the Faculty of Science or at the College de France, and friendly relationship were established. But the essential lies in a posthumous controversy where Claude Bernard, denying the role of microbes in the fermentation, seems to criticize Pasteur's assertions and, later, his method and vision. We shall report here the exchanges which concern these two scientists and, beyond that, the scientific approach.

The Chi-Square test (χ 2 test) is a family of tests based on a series of assumptions and is frequently used in the statistical analysis of experimental data. The aim of our paper was to present solutions to common problems when applying the Chi-square tests for testing goodness-of-fit, homogeneity and independence. The main characteristics of these three tests are presented along with various problems related to their application. The main problems identified in the application of the goodness-of-fit test were as follows: defining the frequency classes, calculating the X 2 statistic, and applying the χ 2 test. Several solutions were identified, presented and analyzed. Three different equations were identified as being able to determine the contribution of each factor on three hypothesizes (minimization of variance, minimization of square coefficient of variation and minimization of X 2 statistic) in the application of the Chi-square test of homogeneity. The best solution was directly related to the distribution of the experimental error. The Fisher exact test proved to be the "golden test" in analyzing the independence while the Yates and Mantel-Haenszel corrections could be applied as alternative tests.

The scattering diagram of a couple of spherical particles is compared to the interference pattern of circular Young slits. This comparison is used to analyze the coupling of light by a couple of particles in the single but also in the multiple scattering cases. This makes possible to explain physically the interaction between light and such a couple of particles, that is for example to distinguish interference pattern, diffaction effects and multiple scattering phenomena. The scattering diagram is rigorously computed with the use of the T-matrix algorithm. Particles are perfectly conducting spheres and their radius are smaller than the wavelength. The scattering diagram and the backscattering cross section are analyzed as functions of the distance between particles.

Fetveit Arild, Pasteur Jean-Louis. N'existe-t-il rien de tel qu'un texte ? L'anti-essentialisme et la domination du lecteur. In: Quaderni, n°33, Automne 1997. L'État communicant, des formes de la communication gouvernementale. pp. 57-73.

Mediterranean areas are characterized by a strong spatial variability that makes highly complex the soil hydrological response. Moreover, Mediterranean climate has a marked seasonal variability that provokes dramatic changes on the soil properties determining the hydrological behavior, such as soil water content, crust formation or soil water repellency (SWR). Thus, soil hydrological and erosive response in Mediterranean areas can be highly time- as well space-dependant. The main goal of this study was to characterize the relations between SWR, aspect and vegetation, determining the soil hydrological and erosive response throughout the rainy period in different microenvironments of opposite hillslopes. This study was undertaken in a small catchment located in the South of Spain. Erosion plots were installed in the north- and the south-facing hillslope, in areas with different vegetal cover, and runoff and sediments were collected. Moreover, precipitation parameters were recorded and SWR measurements were performed. SWR proved to have a significant effect on the soil hydrological response, but this influence was modulated by seasonal changes and by the discontinuities on the repellent layer. In general, the influence of SWR was restricted to the first rains after the summer and was greater on the north-facing hillslope due to the more continuous vegetation cover. The more important precipitation parameter influencing runoff generated was maximum rainfall intensity in ten minutes (Imax). The relation between Imax and overland flow showed a contrasting seasonal behavior in the north-facing hillslope and, on the contrary, remained homogeneous throughout the year in the south-facing hillslope.

Henry Toussaint (1847-1890) is a veterinary who studied in Veterinary School of Lyon with his great master Auguste Chauveau the famous physiologist. This place is the First School founded in Europe at the end of the XVIIIth century and has opened a way of thinking. His carrer brilliant and rich begins first in Lyon and then when he is named Professor of Anatomy and Physiology at the Veterinary School of Toulouse. Doctor of Science and Doctor of Medecine Toussaint applies "the experimental method" to his research in his laboratory and makes a lot of publications. He starts with Anatomy, then Physiology and soon he prioritizes his research to infestious diseases which cause serious damage to cattle in this time. He developes his own methods about anthrax an its "bacteridie", its nature, its way of culture and especially he studies the physiopathology of this disease. Pasteur is a renowned scientist who does study Microbiology at the same time in his laboratory in Paris, and precisely anthrax. He has explained his theories about "microbes" and has predominant advice. Toussaint admires Pasteur; in the year 1879 he finds first and isolates the microbe of "cholera des poules" (now Pasteurella) and gives Pasteur this new germ which will be used by Pasteur for his particular works about reducing of virulence by successive subcultures. In 1880 with his publishing on July 12 at the Academy of Science, Toussaint presents his successful result with an attenuated vaccine against anthrax: he has got protection against anthrax for dogs and sheep by using a vaccine which he has reduced off virulence by chemical manner. Academy congratulates him. Pasteur jealous of one's reputation contests the demonstration of Toussaint because he does not believe in the chemical method too different from his tests but will make use of this method for an experience open to the public in Pouilly-le-Fort in 1881. After this promotional event Pasteur will product and sell vaccines maked in his laboratory in Paris with the first chemical method of Toussaint. Pasteur gets glory and money. In the following time Toussaint tries another research on tuberculosis but soon he feels the first attacks of a neurologic illness and inescapably his mind declines until the death in 1890.

The paper studies a class of experience good models in a new way. We focus on signaling games close to Akerlof’s market for lemons, in which a seller sells a good to a buyer, who ignores the quality of the good during the transaction. In this context, we first establish some properties of the mixed Perfect Bayesian Equilibria. Then we turn to the concept of bestreply matching (BRM) developed by Droste, Kosfeld & Voorneveld (2002, 2003) for games in normal form. BRM equilibria respect a consistency which is different from the Nash equilibrium one: in a BRM equilibrium, the probability assigned by a player to a pure strategy is linked to the number of times the opponents play the strategies to which this pure strategy is a best reply. We extend this logic to signaling games in extensive form and apply the new obtained concept to our experience good models. This new concept leads to a very simple rule of behavior, which is consistent, different from the Perfect Bayesian Equilibrium behavior, different from Akerlof’s result, and can be socially efficient.

This paper analyzes the answer given by Pasteur to those who defended the spontaneous generation theory and evaluates the impact these arguments had on the history of public hygiene. Because of that, the article emphasizes transmission of germs, rather than the origin of life, which has been quite analyzed. It also discusses the criticism Pasteur made to naturalists' arguments and tries to show that it is possible to say there is a certain continuity between the air-related concerns on the part of classic hygienists, most of which infectionists, and Pasteur's concern with germs spread in the air.

Louis Pasteur long has been heralded as the "father of modern hygiene, public health and much of modern medicine," despite early controversies regarding his findings and methodology. A recently published biography, however, has shed new light on both Pasteur's scientific acumen and integrity. Reactions to this portrayal have been mixed. This article provides an overview of Pasteur's life and the debate regarding his scientific discoveries and honesty that has ensued for more than 100 years, with insights gained from both supporters and critics of the new biography by Gerald L. Geison.