Alquimia, Ocultismo, Maçonaria: o ouro e o simbolismo hermético dos cadinhos (Séculos XVIII e XIX)

Este artigo apresenta a arqueologia das enigmáticas marcas impressas na base de cadinhos dos séculos XVIII e XIX recuperados nas escavações da Casa da Moeda do Rio de Janeiro, na década de 1980, e a explanação do seu significado simbólico à luz da alquimia, do ocultismo e da Maçonaria. Espraiando-se extraordinariamente mundo afora através de uma bem-sucedida estratégia de comunicação visual, a Maçonaria utilizou símbolos herméticos para a difusão de seus princípios nos mais diferentes suportes. Aparentemente estamos diante de um sinal de reconhecimento maçônico, o sinal exterior de uma organização oculta, só partilhado por iniciados e incompreensível para os demais, que contribuiu para difundir veladamente a doutrina maçônica por diferentes pontos do globo

Liens entre microbiote intestinal et comportement de type anxiodépressif chez le rongeur

International audienc

Characterization of Ordered 3D Arrays of Ag2_2S Nanocrystallites

Reverse micelles have been used to synthetize 5.6 nm silver sulfide particles. These nanoparticles are coated with dodecanethiol, extracted from reverse micelles and then dissolved in heptane. The extracting process induces a size selection with a decrease in the polydispersity from 30% to 14%. By leaving a drop of a solution on any support, or immerse the support in the solution, mono and multilayers made of nanosized particles are formed. The monolayer is arranged in a hexagonal network whereas the 3D multilayers are arranged in a face centered cubic structure. From T.E.M. (Transmission Electron Microscopy) and G.I.S.A.X.S (Grazing Incidence Small Angle X-ray Scattering) techniques morphological information is provided.
Dans cet article, la préparation et la caractérisation de réseaux ordonnés à deux et trois dimensions de nanocristallites de sulfure d'argent sont présentées. La morphologie des réseaux est étudiée à l'aide de deux techniques : la microscopie électronique à transmission et la diffusion des rayons X aux petits angles sous incidence rasante. La microscopie électronique met en évidence un empilement de nanoparticules selon une structure cubique à faces centrées. La distance moyenne entre particules et le nombre de couches formant la structure tridimensionnelle sont déterminés

Nouvel appareillage de diffraction X pour l'analyse de l'état mécanique (contraintes et microdéformations) de films minces nanocristallins

L'état mécanique des couches minces influence considérablement l'ensemble de leurs proprietés physiques. La connaissance des contraintes résiduelles et des microdéformations présentes dans ces matériaux revêt donc une importance particulière. Le caractère nanocristallin des ces films rend difficile l'application des méthodes classiques de diffraction X (sin2Ψ et largeur intégrale ou Warren-Averbach) couramment utilisées dans le cas des échantillons massifs. En effet, les pics de diffraction sont larges et peu intenses. Nous avons mis au point un dispositif expérimental de conception originale qui permet de contourner ces difficultés. Il s'appuie sur les trois caractéristiques suivantes : source de rayons X de forte intensité (rayonnement synchrotron ou générateur à anode tournante), trajet du faisceau X incident et diffracté sous vide, et enregistrement du spectre l'aide d'un détecteur à localisation. Les résultats obtenus sur des films Inox 304L et Cu-Mo illustrent bien les potentialités de ce nouvel appareillageThe mechanical state in thin films very much influence their physical properties. The knowledge of residual stresses and microstresses in these materials is therefore very important. Classical methods of X-ray diffraction (sin2Ψ and integral width or Warren-Averbach) are difficult to apply in such materials because the diffracted intensities are weak due to the nanocrystalline structure of these films. In order to solve these difficulties, we developed an original X-ray diffraction set-up. Its main features are the followings : intense Xray source (synchrotron radiation or rotating anode), incident and diffracted x-ray path under vacuum, and recording of the spectrum with a proportional sensitive detector. Results obtained for 304L stainless steel and Cu-Mo thin films show the full potentialities of such an equipment

Behavioral, neurochemical, and electrophysiological characterization of a genetic mouse model of depression

Depression is a multifactorial illness and genetic factors play a role in its etiology. The understanding of its physiopathology relies on the availability of experimental models potentially mimicking the disease. Here we describe a model built up by selective breeding of mice with strikingly different responses in the tail suspension test, a stress paradigm aimed at screening potential antidepressants. Indeed, “helpless” mice are essentially immobile in the tail suspension test, as well as the Porsolt forced-swim test, and they show reduced consumption of a palatable 2% sucrose solution. In addition, helpless mice exhibit sleep–wakefulness alterations resembling those classically observed in depressed patients, notably a lighter and more fragmented sleep, with an increased pressure of rapid eye movement sleep. Compared with “nonhelpless” mice, they display higher basal seric corticosterone levels and lower serotonin metabolism index in the hippocampus. Remarkably, serotonin(1A) autoreceptor stimulation induces larger hypothermia and inhibition of serotoninergic neuronal firing in the nucleus raphe dorsalis in helpless than in nonhelpless mice. Thus, helpless mice exhibit a decrease in serotoninergic tone, which evokes that associated with endogenous depression in humans. Finally, both the behavioral impairments and the serotoninergic dysfunction can be improved by chronic treatment with the antidepressant fluoxetine. The helpless line of mice may provide an opportunity to approach genes influencing susceptibility to depression and to investigate neurophysiological and neurochemical substrates underlying antidepressant effects

Large Enhancement of the Third-order Optical Susceptibility in Cu-silica Composites Produced by Low-Energy High-Current Ion Implantation

3 pages, 3 figures, 1 table.-- PACS: 61.46.+w; 78.67.Bf; 42.65.An; 42.65.Hw; 61.72.Ww; 61.80.Jh; 73.22.LpLow-energy high-current ion implantation in silica at a well-controlled substrate temperature has been used to produce composites containing a large concentration of spherical Cu clusters with an average diameter of 4 nm and a very narrow size distribution. A very large value for the third-order optical susceptibility, (3) = 10–7 esu, has been measured in the vicinity of the surface plasmon resonance by degenerate four-wave mixing at 585 nm. This value is among the largest values ever reported for Cu nanocomposites. Additionally, the response time of the nonlinearity has been found to be shorter than 2 ps. The superior nonlinear optical response of these implants is discussed in terms of the implantation conditions.This work has been partially supported by the EU under the BRPR-CT98-0616 project, by CAM, Spain, under the 075/0038/1998 project, and by the CSIC-CNRS 2000FR0026 agreement for traveling funding. J.O. wishes to thank CSIC for funding his position. A.L.S. gratefully acknowledges the Alexander von Humboldt foundation and RFBR 99-02-17767 for financial support.Peer reviewe