Ceramics with metallic lustre decoration. A detailed knowledge of Islamic productions from 9th century until Renaissance

Cette publication a fait l'objet d'un article publié en 2012 dans la revue "Matériaux and Techniques" 100, 1 Pages 47-68, disponible sur : http://hal-ensmp.archives-ouvertes.fr/hal-00686405This paper describes research on the technological evolution of glazed ceramics with a metallic lustre decoration starting from their emergence in the Near East until the Hispano-Moresque productions. That research covers the main known Islamic production sites and periods: Abbasid (Mesopotamia); Fatimid (Egypt); Timurid, Mongol, and Safavid (Iran); Ayyubid and Mamluk (Syria); Nasrid and Hispano-Moresque (Spain). It was allowed by the access to more than hundred full preserved objects or fragments supplied by French national museums (Musée du Louvre DAI, Musée national du Moyen Age, Musée national de Céramique). The characterisation of the composition and structure of the ceramics and of their decoration is mostly done through non-destructive analyses methods. The thickness and metal content of the surface lustre layers are quantified thanks to ion beam analyses performed on a particle accelerator: PIXE (particle-induced X-ray emission) for the terracotta and glazes composition and RBS (Rutherford backscattering spectrometry) for the thickness and metal content of the lustre surface layers. The preliminary results show that the features of the decorated ceramics have undergone dramatic variations when transmitted from a production to another, not only, as expected, in the composition of terracotta and glazes, but also in the thickness, the structure and the composition distribution of the lustre layers

Ceramics with metallic lustre decoration. A detailed knowledge of Islamic productions from 9th century until Renaissance

This paper describes research on the technological evolution of glazed ceramics with a metallic lustre decoration starting from their emergence in the Near East until the Hispano-Moresque productions. That research covers the main known Islamic production sites and periods: Abbasid (Mesopotamia); Fatimid (Egypt); Timurid, Mongol, and Safavid (Iran); Ayyubid and Mamluk (Syria); Nasrid and Hispano-Moresque (Spain). It was allowed by the access to more than hundred full preserved objects or fragments supplied by French national museums (Mus\'ee du Louvre DAI, Mus\'ee national du Moyen Age, Mus\'ee national de C\'eramique). The characterisation of the composition and structure of the ceramics and of their decoration is mostly done through non-destructive analyses methods. The thickness and metal content of the surface lustre layers are quantified thanks to ion beam analyses performed on a particle accelerator: PIXE (particle-induced X-ray emission) for the terracotta and glazes composition and RBS (Rutherford backscattering spectrometry) for the thickness and metal content of the lustre surface layers. The preliminary results show that the features of the decorated ceramics have undergone dramatic variations when transmitted from a production to another, not only, as expected, in the composition of terracotta and glazes, but also in the thickness, the structure and the composition distribution of the lustre layers.Comment: 23 pages ; non-destructive IBA analyses of more than 120 objects (fragments or entire objects) from all origins in the Islamic world and from 9th century to 18th centur

Christian Bessy, Les licenciements économiques entre la loi et le marché

Aucouturier Anne-Lise. Christian Bessy, Les licenciements économiques entre la loi et le marché. In: Genèses, 17, 1994. Les objets et les choses, sous la direction de Francine Soubiran-Paillet. pp. 164-167

Christian Bessy, Les licenciements économiques entre la loi et le marché

Aucouturier Anne-Lise. Christian Bessy, Les licenciements économiques entre la loi et le marché. In: Genèses, 17, 1994. Les objets et les choses, sous la direction de Francine Soubiran-Paillet. pp. 164-167

Les dispositifs pour l'emploi et les jeunes sortant de scolarité : une utilisation massive, des trajectoires diversifiées

[eng] Employment Schemes and School Leavers: Widespread Deployment and Diverse Career paths. More than four out of every ten school leavers with the baccalauréat or less are placed on employment policy schemes to integrate them into the world of work: contrats de qualification, contrats d'adaptation, stages d'initiation à la vie professionnelle (SIVP) and contrats emploi-solidarité (CES). These measures essentially target the least qualified, but each one is aimed at a specific group. Whereas the contrats de qualification and the contrats d'adaptation are for young people with relatively high qualifications, the CES and the SIVP cover a relatively unskilled population. . If the effectiveness of a scheme is measured by the probability of finding jobs outside government schemes, the contrat de qualification posts better results than the SIVP and the CES. A study of individual career paths confirms the advantage of contrats de qualification, which more often lead to stable and non-government-assisted jobs. At the other end of the spectrum, the CES is prone to lead to a string of such contracts. It is also worth noting that a low level of qualification is not necessarily a handicap for certain schemes. [ger] Der Eintritt in das Berufsleben nach der Sekundarstufe: die Eingliederung in den einzelnen Regionen im Jahre 1993 . Die râumliche Analyse der beruflichen Eingliederung der Jugendlichen nach Verlassen der Sekundarstufe kann sich nicht auf eine bloBe Analyse der Arbeitslosenquote beschrànken. Denn die regionalen Unterschiede ergeben sich ebenfalls aus den Arbitrationen, die in jeder Region bei der Inanspruchnahme der beschàftigungsfôrdernden MaBnahmen vorgenommen werden: Arbeitsvertràge zur Anpassung an die beruflichen Erfordernisse, Arbeitsvertràge zur Erlangung einer beruflichen Qualification, Solidaritâts-/Beschâftigungsvertràge sowie Ausbildungs- praktika. In den Regionen mit stark tertiàrer Ausrichtung nehmen somit manche verstârkt die Ausbildungspraktika in Anspruch (Pariser Region, Provence, Alpes, Côte d'Azur), wâhrend andere (Region Midi-Pyrénées) den Solidaritàts-/Beschâftigungs- vertràgen den Vorzug geben. Der EingliederungsprozeB scheint oftmals sogar eher vom regionalen Kontext als vom Ausbildungsniveau der betreffenden Personen gepràgt zu sein. Selbst innerhalb einer Region kann er starken Schwankungen unterliegen; dièse Unterschiede finden im ùbrigen in der relativen Prekaritàt der innerregionalen Beschàftigungs- zonen ihren Niederschlag. [spa] Dispositivos para el empleo y jôvenes que uso masivo y trayectorias diversificadas . Mâs de cuatro de cada diez jôvenes que salen de la escolaridad al nivel del bachillerato o a un nivel inferior, hacen uso de los dispositivos de fomento del empleo tendentes a la insertion en la vida profesional : contratos de trabajo en prâcticas, contratos de aprendizaje, précticas de iniciaciôn a la vida profesional (SIVP), contratos temporales de utilidad social (CES). Se dirigen estas medidas ante todo a aquellos jôvenes menos cualificados, tiene cada una sin embargo pûblico propio : cuando los contratos de trabajo en prâcticas y de aprendizaje atraen a unos jôvenes cuyo nivel de formation es relativamente alto, CES y SIVP reclutan una poblaciôn poco cualificada. . salen de la escolaridad.. Si la eficiencia de cualquier dispositivo se mide en la probabilidad de acceso a unos empleos no ayudados, los contratos en prâcticas registran mejores resultados que los SIVP o los CES. El estudio de las trayectorias individuates confirma la ventaja de los contratos en prâcticas, que desembocan a menudo en unas situaciones de empleo estable y no ayudado, cuando al otro extremo los CES favorecen un encadenamiento de este tipo de contrato. Se nota asimismo que, en cuanto a ciertos dispositivos, un nivel de formation poco elevado no es necesariamente una desventaja. [fre] Les dispositifs pour l'emploi et les jeunes sortant de scolarité : une utilisation massive, des trajectoires diversifiées . Sur dix jeunes sortant de scolarité au niveau baccalauréat et moins, plus de quatre passent par les dispositifs de la politique de l'emploi visant à l'insertion dans la vie professionnelle : contrats de qualification, contrats d'adaptation, stages d'initiation à la vie professionnelle (SIVP), contrats emploi-solidarité (CES). Ces mesures, qui s'adressent principalement aux moins qualifiés, ont cependant chacune un public privilégié : alors que les contrats de qualification et d'adaptation drainent des jeunes dont le niveau de formation est relativement élevé, CES et SIVP recrutent une population peu qualifiée. . Si l'efficacité d'un dispositif se mesure par la probabilité d'accéder à des emplois non aidés, les contrats de qualification enregistrent alors de meilleurs résultats que les SIVP ou les CES. L'examen des trajectoires individuelles confirme l'avantage des contrats de qualification, qui aboutissent le plus souvent à des situations d'emploi stable et non aidé, alors qu'à l'autre extrémité, les CES prédisposent à un enchaînement de ce type de contrats. On note aussi que, pour certains dispositifs, un niveau de formation peu élevé n'est pas forcément un handicap.

Genomic sequence of the prophage-free lactococcus lactis strain il6288

We report here the genome sequence of IL6288, a prophage-free derivative of Lactococcus lactis subsp. lactis strain IL1403, and confirm precise deletion of all prophages. Several single-nucleotide variations and an extra copy of the IS981 element, apparently having a minor influence on cell physiology, were also detected in the IL6288 genome

Characterization of a prophage-free derivative strain of Lactococcus lactis ssp lactis IL1403 reveals the importance of prophages for phenotypic plasticity of the host

Lactococcus lactis is a lactic acid bacterium of major importance for the dairy industry and for human health. Recent sequencing surveys of this species have provided evidence that all lactococcal genomes contain prophages and prophage-like elements. The prophage-related sequences encompass up to 10% of the bacterial chromosomes and thus contribute significantly to the genetic diversity of lactococci. However, the impact of these resident prophages on the physiology of L. lactis is presently unknown. The genome of the first sequenced prototype strain, L. lactis ssp. lactis IL1403, contains six prophage-like elements which together represent 6.7% of the ID 403 chromosome. Diverse prophage genes other than those encoding phage repressors have been shown to be expressed in lysogenic conditions, suggesting that prophage genes are indeed able to modulate the physiology of their host. To elucidate the effect of resident prophages on the behavior of L. lactis in different growth conditions, we constructed and characterized, for the first time, a derivative strain of IL1403 that is prophage-free. This strain provides unique experimental opportunities for the study of different aspects of lactococcal physiology using the well-defined genetic background of IL1403. Here, we show that resident prophages modify the growth and survival of the host strain to a considerable extent in different conditions, including in the gastrointestinal environment. They also may affect cellular autolytic properties and the host cells' susceptibility to virulent bacteriophages and antimicrobial agents. It thus appears that prophages contribute significantly to lactococcal cell physiology and might play an important role in the adaptation of L. lactis to cultivation and environmental conditions

Gold like lustre: nanometric surface treatment for decoration of glazed ceramics in ancient Islam, Moresque Spain and Renaissance Italy

International audienceLustre is one of the most fascinating surface decorative effects produced on glazed ceramics. This technique seems to have been born in the ninth century in factories created by the Arabs during their conquests in the Orient (Mesopotamia, Egypt and Persia). Arab potters spread their knowhow all over the Mediterranean basin, especially Spain. Italian Renaissance potters succeeded in applying it to their production. The technique is based on a specific firing of the glazed pottery in a reducing atmosphere in the presence of metallic salts. The result is a surface layer with a metallic appearance, exhibiting various colours, from gold to brown or red. This paper provides the chemical nature and the physical structure of ancient gold like lustre layers and compares them with contemporary lustres produced by a Spanish craftsman reproducing the traditional Islamic techniques. Various analytical investigations (atomic force microscopy, high resolution SEM, particle induced X-ray emission, Rutherford backscattering, TEM, X-ray induced photoelectron spectroscopy, time of flight SIMS and grazing X-ray diffraction) were carried out as well as investigations into the coloured appearance by spectrophotometry. The results show that the lustre layer consists of silver and copper particles of nanometric dimensions dispersed in a glassy matrix. A model of the lustre formation is proposed wherein the development of a new superficial glaze is described. Comparison between ancient and modern production shows how the techniques have varied through the ages

Contribution of antibody and T cell-specific responses to the progression of 139A-scrapie in C57BL/6 mice immunized with prion protein peptides

Prion diseases are associated with the conversion of the normal host cellular prion protein to an abnormal protease-resistant (PrPres) associated with infectivity. No specific immune response against prions develops during infection due to the strong tolerance to cellular prion protein. We examined the protective potential on prion diseases of immune responses elicited in C57BL/6 mice with PrP peptides 98-127 (P5) or 158-187 (P9) with CpG. After immunization, P5-treated mice developed high titer and long-lasting Abs, and P9-treated mice developed transient IFN-γ secreting T cells and poor and variable Ab responses. Both treatments impaired early accumulation of PrPres in the spleen and prolonged survival of mice infected with 139A scrapie. Additional P9 boosts after 139A infection sustained the T cell response and partially inhibited PrPres early accumulation but did not improve the survival. Surprisingly, when P9 injections were started 1 mo after infection and repeated subsequently, specific T cell and Ab responses were impaired and no beneficial effect on prion disease was observed. After a single injection of P9, the number of IFN-γ secreting CD4 T cells was also reduced in mice 8- to 10-wk postinfection compared with healthy mice. In vivo and in vitro removal of CD4CD25 T cells restored the T cell response to P9 in infected mice. In conclusion, CD4 T cells as well as Abs might participate to the protection against scrapie. Of importance, the peripheral accumulation of PrPres during infection negatively interferes with the development of T and B cell responses to PrP and regulatory T cells might contribute to this phenomenon

Contribution de la diffraction de rayons X sous incidence rasante à l'étude de céramiques lustrées

International audienceLa structure cristallographique de lustres dorés archéologiques (Fustat, Egypte, IX-XIème siècle) et contemporains (Grenade, Espagne), a été étudiée par diffraction de rayons X. La configuration classique Bragg - Brentano, ainsi que l'incidence rasante avec des angles d'incidence compris entre 0,5° et 10°, ont été utilisées. Sur de tels échantillons présentant des ensembles de couches complexes, il n'a pas été possible de connaître exactement les profondeurs explorées par les analyses. Cependant un calcul simplifié, basé sur l'absorption des rayons X, démontre que la profondeur minimale atteinte est de l'ordre de 85 nm. Sur les glaçures anciennes, la cassitérite, la diopside et le quartz sont mis en évidence ; sur les glaçures modernes, la cassitérite apparaît uniquement. En incidence rasante, seule la raie la plus intense de l'argent (111) est notée sur les lustres anciens. L'un d'entre eux riche en cuivre présente trois raies du cuivre métallique ; l'existence d'oxyde de cuivre n'a pu être affirmée à cause de possibles superpositions avec la cassitérite et le quartz. Sur les lustres contemporains, la présence d'argent métallique est révélée par les deux premières raies (111) et (200). Les raies d'argent sont visiblement élargies ce qui traduit l'existence de cet élément sous forme de petites cristallites. Le pic (200) n'étant pas perturbé par d'autres éléments, a permis en utilisant la formule de Scherrer, de déterminer une taille des cristallites d'argent de 15 nm