Ursinia nana (Anthemideae, Asteraceae), and adventive from South Africa which is becoming naturalized in the Iberian Peninsula. Observations about its reproductive biology and fruit dispersal mechanism.

The presence of Ursinia nana, an Anthemideae of South-African origin which has been introduced into the NE Iberian Peninsula, is reported for the fi rst time in Europe. The data offered cover its precise location, morphology, chromosome number, ecology and a population census, as well as its life cycle, fl oral structure, reproductive biology and fruit dispersal mechanisms. Of special note are the clear predominance of autogamy (geitonogamy) over xenogamy as a reproductive system and the large number of fruits produced with high and immediate germinative capacity. These characteristics permit rapid colonization by the introduced species, which can become invasive. However, fruit predation by the ant Messor barbarus points to a natural mechanism that helps regulate population growth and makes biological control possible. Finally its possibilities of expansion in the colonized area and of naturalization in the NE Iberian Peninsula are assessed.

EORTC topics in neurooncology: The long path from a focus on neurological complications of cancer towards molecularly defined trials and therapies in neurooncology

Over the past decade a series of trials of the EORTC Brain Tumor Group (BTG) has substantially influenced and shaped the standard-of-care of primary brain tumors. All these trials were coupled with biological research that has allowed for better understanding of the biology of these tumors. In glioblastoma, EORTC trial 26981/22981 conducted jointly with the National Cancer Institute of Canada Clinical Trials Group showed superiority of concomitant radiochemotherapy with temozolomide over radiotherapy alone. It also identified the first predictive marker for benefit from alkylating agent chemotherapy in glioblastoma, the methylation of the O6-methyl-guanyl-methly-transferase (MGMT) gene promoter. In another large randomized trial, EORTC 26951, adjuvant chemotherapy in anaplastic oligodendroglial tumors was investigated. Despite an improvement in progression-free survival this did not translate into a survival benefit. The third example of a landmark trial is the EORTC 22845 trial. This trial led by the EORTC Radiation Oncology Group forms the basis for an expectative approach to patients with low-grade glioma, as early radiotherapy indeed prolongs time to tumor progression but with no benefit in overall survival. This trial is the key reference in deciding at what time in their disease adult patients with low-grade glioma should be irradiated. Future initiatives will continue to focus on the conduct of controlled trials, rational academic drug development as well as systematic evaluation of tumor tissue including biomarker development for personalized therapy. Important lessons learned in neurooncology are to dare to ask real questions rather than merely rapidly testing new compounds, and the value of well designed trials, including the presence of controls, central pathology review, strict radiology protocols and biobanking. Structurally, the EORTC BTG has evolved into a multidisciplinary group with strong transatlantic alliances. It has contributed to the maturation of neurooncology within the oncological sciences.

Development and Implementation of an Expert System for Forecasting Fog on US Highway 30 in Cedar Rapids, Iowa, HR-357, 1996

Several accidents, some involving fatalities, have occurred on U.S. Highway 30 near the Archer Daniels Midland Company (ADM) Corn Sweeteners plant in Cedar Rapids, Iowa. A contributing factor to many of these accidents has been the large amounts of water (vapor and liquid) emitted from multiple sources at ADM's facility located along the south side of the highway. Weather and road closure data acquired from IDOT have been used to develop a database of meteorological conditions preceding and accompanying closure of Highway 30 in Cedar Rapids. An expert system and a FORTRAN program were developed as aids in decision making with regard to closure of Highway 30 near the plant. The computer programs were used for testing, evaluation, and final deployment. Reports indicate the decision tools have been successfully implemented and were judged to be helpful in forecasting road closures and in reducing costs and personnel time in monitoring the roadway.

Being Female: a handicap for researchers in the competion for NCCR.

The Swiss National Science Foundation made a call for National Centers fo Competence in Research (NCCR) for the first time in 1999 and 2004. Together, these announcements concerned all disciplines and led to 126 preproposals, which were put forward by 2134 men and women researchers. It can be assumed that this operation mobilised Swiss researchers who regarded themselves as particularly well qualified to conduct high-level research in their field. The article uses network analysis and regression analysis methods to examine to what extend women had a lower success rate than men in the two selection rounds because of their sex. On the whole, the findings attest the gender neutrality of the National Science Foundation's selection procedures. However, they also confirm the well-known fact that women scientists are less represented in the higher echelons of academia and concentrated in the social sciences and humanities, as well as showing that this concentration reduces women's chances of success in scientific competition. The article shows that unequal gender-specific success rates prior to the NCCR funding contest play a fairly significant role.

A Multi-Project Scheduling Procedure for Transportation Projects, Part II, HR-339, 1994

The Iowa Department of Transportation (IDOT) has been requiring Critical Path Method (CPM) schedules on some larger or more schedule sensitive projects. The Office of Construction's expectations for enhanced project control and improved communication of project objectives have not been fully met by the use of CPM. Recognizing that the current procedures might not be adequate for all projects, IDOT sponsored a research project to explore the state-of-the-art in transportation scheduling and identify opportunities for improvement. The first phase of this project identified a technique known as the Linear Scheduling Method (LSM) as an alternative to CPM on certain highway construction projects. LSM graphically displays the construction process with respect to the location and the time in which each activity occurs. The current phase of this project was implemented to allow the research team the opportunity to evaluate LSM on all small groups of diverse projects. Unlike the first phase of the project, the research team was closely involved in the project from early in the planning phase throughout the completion of the projects. The research strongly suggests that the linear scheduling technique has great potential as a project management tool for both contractors and IDOT personnel. However, before this technique can become a viable weapon in the project management arsenal, a software application needs to be developed. This application should bring to linear scheduling a degree of functionality as rich and as comprehensive as that found in microcomputer based CPM software on the market today. The research team recommends that the IDOT extend this research effort to include the development of a linear scheduling application.

Differentiation associated regulation of microRNA expression in vivo in human CD8+ T cell subsets.

BACKGROUND: The differentiation of CD8+ T lymphocytes following priming of naïve cells is central in the establishment of the adaptive immune response. Yet, the molecular events underlying this process are not fully understood. MicroRNAs have been recently shown to play a key role in the regulation of haematopoiesis in mouse, but their implication in peripheral lymphocyte differentiation in humans remains largely unknown. METHODS: In order to explore the potential implication of microRNAs in CD8+ T cell differentiation in humans, microRNA expression profiles were analysed using microarrays and quantitative PCR in several human CD8+ T cell subsets defining the major steps of the T cell differentiation pathway. RESULTS: We found expression of a limited set of microRNAs, including the miR-17~92 cluster. Moreover, we reveal the existence of differentiation-associated regulation of specific microRNAs. When compared to naive cells, miR-21 and miR-155 were indeed found upregulated upon differentiation to effector cells, while expression of the miR-17~92 cluster tended to concomitantly decrease. CONCLUSIONS: This study establishes for the first time in a large panel of individuals the existence of differentiation associated regulation of microRNA expression in human CD8+ T lymphocytes in vivo, which is likely to impact on specific cellular functions.

Long-lived States in an intrinsically disordered protein domain

Long-lived states (LLS) are relaxation-favoured eigenstates of J-coupled magnetic nuclei. LLS were measured, along with classical 1H and 15 N relaxation rate constants, in aminoacids of the N-terminal Unique domain of the c-Src kinase (USrc), which is disordered in vitro under physiological conditions. The relaxation rates of LLS are a probe for motions and interactions in biomolecules. LLS of the aliphatic protons of glycines, with lifetimes ca. four times longer than their spin-lattice relaxation times, are reported for the first time in an intrinsically disordered protein domain (IDP). LLS relaxation experiments were integrated with 2D spectroscopy methods, further adapting them for studies on proteins.

Phenotypic plasticity in salmonid embryos : characterizing pathogen-induced stress effects on heritable variation in traits and reaction norms

Les pressions écologiques peuvent varier tant en nature qu'en intensité dans le temps et l'espace. C'est pourquoi, un phénotype unique ne peut pas forcément conférer la meilleure valeur sélective. La plasticité phénotypique peut être un moyen de s'accommoder de cette situation, en augmentant globalement la tolérance aux changements environnementaux. Comme pour tout trait de caractère, une variation génétique doit persister pour qu'évoluent les traits plastiques dans une population donnée. Cependant, les pressions extérieures peuvent affecter l'héritabilité, et la direction de ces changements peut dépendre du caractère en question, de l'espèce mais aussi du type de stress. Dans la présente thèse, nous avons cherché à élucider les effets des pressions pathogéniques sur les phénotypes et la génétique quantitative de plusieurs traits plastiques chez les embryons de deux salmonidés, la palée (Coregonus palaea), et la truite de rivière (Salmo trutta). Les salmonidés se prêtent à de telles études du fait de leur extraordinaire variabilité morphologique, comportementale et des traits d'histoire de vie. Par ailleurs, avec le déclin des salmonidés dans le monde, il est important de savoir combien la variabilité génétique persiste dans les normes de réaction afin d'aider à prédire leur capacité à répondre aux changements de leur milieu. Nous avons observé qu'une augmentation de la croissance des communautés microbiennes symbiotiques entraînait une mortalité accrue et une éclosion précoce chez la palée, et dévoilait la variance génétique additive pour ces deux caractères (Chapitres 1-2). Bien qu'aucune variation génétique n'ait été trouvée pour les normes de réaction, nous avons observé une variabilité de la plasticité d'éclosion. Néanmoins, on a trouvé que les temps d'éclosion étaient corrélés entre les environnements, ce qui pourrait limiter l'évolution de la norme de réaction. Le temps d'éclosion des embryons est lié à la taille des géniteurs mâles, ce qui indique des effets pléiotropiques. Dans le Chapitre 3, nous avons montré qu'une interaction triple entre la souche bactérienne {Pseudomonas fluorescens}, l'état de dévelopement de l'hôte ainsi que ses gènes ont une influence sur la mortalité, le temps d'éclosion et la taille des alevins de la palée. Nous avons démontré qu'une variation génétique subsistait généralement dans les normes de réaction des temps d'éclosion, mais rarement pour la taille des alevins, et jamais pour la mortalité. Dans le même temps, nous avons exhibé que des corrélations entre environnements dépendaient des caractères phénotypiques, mais contrairement au Chapitre 2, nous n'avons pas trouvé de preuve de corrélations transgénérationnelles. Le Chapitre 4 complète le chapitre précédent, en se plaçant du point de vue moléculaire, et décrit comment le traitement d'embryons avec P. fluorescens s'est traduit par une régulation négative d'expression du CMH-I indépendemment de la souche bactérienne. Nous avons non seulement trouvé une variation génétique des caractères phénotypiques moyens, mais aussi de la plasticité. Les deux derniers chapitres traitent de l'investigation, chez la truite de rivière, des différences spécifiques entre populations pour des normes de réaction induites par les pathogènes. Dans le Chapitre 5, nous avons illustré que le métissage entre des populations génétiquement distinctes n'affectait en rien la hauteur ou la forme des normes de réaction d'un trait précoce d'histoire de vie suite au traitement pathogénique. De surcroît, en dépit de l'éclosion tardive et de la réduction de la taille des alevins, le traitement n'a pas modifié la variation héritable des traits de caractère. D'autre part, dans le Chapitre 6, nous avons démontré que le traitement d'embryons avec des stimuli contenus dans l'eau de conspécifiques infectés a entraîné des réponses propre à chaque population en terme de temps d'éclosion ; néanmoins, nous avons observé peu de variabilité génétique des normes de réaction pour ce temps d'éclosion au sein des populations. - Ecological stressors can vary in type and intensity over space and time, and as such, a single phenotype may not confer the highest fitness. Phenotypic plasticity can act as a means to accommodate this situation, increasing overall tolerance to environmental change. As with any trait, for plastic traits to evolve in a population, genetic variation must persist. However, environmental stress can alter trait heritability, and the direction of this shift can be trait, species, and stressor-dependent. In this thesis, we sought to understand the effects of pathogen stressors on the phenotypes and genetic architecture of several plastic traits in the embryos of two salmonids, the whitefish (Coregonus palaea), and the brown trout (Salmo trutta). Salmonids lend themselves to such studies because their extraordinary variability in morphological, behavioral, and life-history traits. Also, with declines in salmonids worldwide, knowing how much genetic variability persists in reaction norms may help predict their ability to respond to environmental change. We found that increasing growth of symbiotic microbial communities increased mortality and induced hatching in whitefish, and released additive genetic variance for both traits (Chapters 1-2). While no genetic variation was found for survival reaction norms, we did find variability in hatching plasticity. Nevertheless, hatching time was correlated across environments, which could constrain evolution of the reaction norm. Hatching time in the induced environment was also correlated to sire size, indicating pleiotropic effects. In Chapter 3 we report that a three-way interaction between bacterial strain (Pseudomonas fluorescens), host developmental stage, and host genetics impacted mortality, hatching time, and hatchling size in whitefish. We also showed that genetic variation generally persisted in hatching age reaction norms, but rarely for hatchling length, and never for mortality. At the same time, we demonstrated that cross-environmental correlations were trait-dependent, and unlike Chapter 2, we found no evidence of cross-generational correlations. Chapter 4 expands on the previous chapter, moving to the molecular level, and describes how treatment of embryos with P. fluorescens resulted in strain-independent downregulation of MHC class I. Genetic variation was evident not only in trait means, but also in plasticity. In the last two chapters, we investigated population level differences in pathogen- induced reaction norms in brown trout. In Chapter 5, we found that interbreeding between genetically distinct populations did not affect the elevation or shapes of the reaction norms of early life-history traits after pathogen challenge. Moreover, despite delaying hatching and reducing larval length, treatment produced no discernable shifts in heritable variation in traits. On the other hand, in Chapter 6, we found that treatment of embryos with water-borne cues from infected conspecifics elicited population-specific responses in terms of hatching time; however, we found little evidence of genetic variability in hatching reaction norms within populations. We have made considerable progress in understanding how pathogen stressors affect various early life-history traits in salmonid embryos. We have demonstrated that the effect of a particular stressor on heritable variation in these traits can vary according to the trait and species under consideration, in addition to the developmental stage of the host. Moreover, we found evidence of genetic variability in some, but not all reaction norms in whitefish and brown trout.

BMP-2 and TGF-beta1 differentially control expression of type II procollagen and alpha 10 and alpha 11 integrins in mouse chondrocytes.

Bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-beta1 are multifunctional cytokines both proposed as stimulants for cartilage repair. Thus it is crucial to closely examine and compare their effects on the expression of key markers of the chondrocyte phenotype, at the gene and protein level. In this study, the expression of alpha 10 and alpha 11 integrin subunits and the IIA/IIB spliced forms of type II procollagen have been monitored for the first time in parallel in the same in vitro model of mouse chondrocyte dedifferentiation/redifferentiation. We demonstrated that TGF-beta1 stimulates the expression of the non-chondrogenic form of type II procollagen, IIA isoform, and of a marker of mesenchymal tissues, i.e. the alpha 11 integrin subunit. On the contrary, BMP-2 stimulates the cartilage-specific form of type II procollagen, IIB isoform, and a specific marker of chondrocytes, i.e. the alpha 10 integrin subunit. Collectively, our results demonstrate that BMP-2 has a better capability than TGF-beta1 to stimulate chondrocyte redifferentiation and reveal that the relative expressions of type IIB to type IIA procollagens and alpha 10 to alpha 11 integrin subunits are good markers to define the differentiation state of chondrocytes. In addition, adenoviral expression of Smad6, an inhibitor of BMP canonical Smad signaling, did not affect expression of total type II procollagen or the ratio of type IIA and type IIB isoforms in mouse chondrocytes exposed to BMP-2. This result strongly suggests that signaling pathways other than Smad proteins are involved in the effect of BMP-2 on type II procollagen expression.

Kinship, ritual kinship and political milieus in an alpine Valley in 19th century

In my paper I will present some results about ritual kinship and political mobilization of popular groups in an alpine Valley: the Val de Bagnes, in the Swiss canton of Valais. There are two major reasons to choose the Val de Bagnes for our inquiry about social networks: the existence of sharp political and social conflicts during the 18th and the 19th century and the availability of almost systematic genealogical data between 1700 and 1900. The starting point of my research focuses on this question: what role did kinship and ritual kinship play in the political mobilization of popular groups and in the organization of competing factions? This question allows us to shed light on some other uses and meanings of ritual kinship in the local society. Was ritual kinship a significant instrument for economic cooperation? Or was it a channel for patronage or for privileged social contacts? The analysis highlights the importance of kinship and godparentage for the building of homogeneous social and political networks. If we consider transactions between individuals, the analysis of 19th century Val de Bagnes gives the impression of quite open networks. Men and women tried to diversify their relations in order to avoid strong dependency from powerful patrons. Nevertheless, when we consider the family networks, we can notice that most relations took place in a structured social space or a specific "milieu", were intense contacts enhanced trust, although political allegiances and social choices were not fully predictable on the basis of such preferential patterns. In a politically conflictual society, like 19th century Bagnes, ritual kinship interacted with kinship solidarities and ideological factors shaping dense social networks mostly based on a common political orientation. Such milieus sustained the building of political factions, which show surprising stability over time. In this sense, milieus are important factors to understand political and religious polarization in 19th century Switzerland.

Environmental changes in the aftermath of Neoproterozoic glaciations: a biogeochemical study of sediments from SW-Gondwana

Abstract The late Neoproterozoic or Ediacaran period, (635 to -543 Ma) is a primordial time in the Earth history corresponding to the beginning of animal life and the most extreme ice ages on Earth. In this dissertation, palaeoenvironmental conditions were reconstructed for Ediacaran, post-Gaskiers shelf deposits in SW- Gondwana and their changes were evaluated according to the diversity of organisms. The present study addresses the question of interactions between biodiversity and environmental change by using the elemental and isotopic geochemistry of sedimentary rocks and associated organic matter, as well as the distribution of hydrocarbon biomarkers. The studied sedimentary sequences are from a large basin extended from the Paraguay belt to the Rio de la Plata craton, including the Corumbâ Group in SW-Brazil (Paraguay belt), the Arroyo del Soldado Group in Uruguay and the Sierras Bayas Group in Argentina (both in the Rio de la Plata craton). Several geochemical signatures of the sediments from Corumbâ and Sierras Bayas groups provides evidence for an euxinic setting in the Ediacaran Ocean: 1) The occurrence of syngenetic pyrite in the Corumbâ Group together with hydrocarbon biomarkers of an anoxic microbial consortium including traces of gammacerane, a distribution of hopanes with maxima at C29 as well as a low pristane/phytane (Pr/Ph) ratio; 2) the occurrence of 34S enrichments within sulfides of the Sierras Bayas Group exceeding the sulfur isotopic composition of coeval carbonate-associated sulfate. In the Arroyo del Soldado Group, an event of reducing conditions was revealed by higher concentrations of redox-sensitive trace elements and negative 513Ccar shifts in all sections. This event is extended to the whole unit in the deepest section and is restricted to tempestites in the two other shallow sections. The persistent negative. ôl3Ccar values recorded at the basinal setting implies strong isotopic gradient between shallow and deep water environments and therefore, a locus of deposition below the redox chemocline. In all studied sections, the excursions, the strong enrichment of authigenic trace-elements, the occurrence of longer chain «-alkanes, gammacerane and low Pr/Ph and Ph/>;-C]a ratios, combined with the previous sedimentological and paleontological observations indicate that the chemistry of the ocean was strongly controlled by the oxygen availability; waters being moderately oxic at the surface and anoxic at depth for much of the Neoproterozoic. This water column stratification was favourable to the storage of large amounts of nutrients in the deep ocean. During upwelling periods, the export of these nutrient-rich waters may have triggered an important bioproductivity in surface waters. Drops in Al3Cc,,.](Cr and positive ôl3Ccllr excursions highlight the increase in primary productivity. Preservation of organic carbon was ensured by reducing conditions at the bottom. The Al3ccar.kcr excursions could also reflect changes in the composition of the primary biomass. New geochemical evidence from SW-Gondwana sections supports a stratified Ediacaran ocean, outside restricted or hypersaline environments, in the aftermath of glaciations. The association of ocean stratification and the appearance of metazoans support the model that the evolution of eukaryotic life was related to the increase of oxygen levels in surface environments due to an efficient recycling of nutrients in the anoxic deep ocean. Résumé Le Néoprotérozoïque terminal, ou Édiacarien (635 à -543 Ma), est un période de première importance dans l'histoire de la Terre, car elle correspond a l'apparition des métazoaires pendant un intervalle de glaciations extrêmes. Le présent mémoire se propose de reconstituer les conditions paléoenvironnementales des dépôts de plateforme mis en place durant l'Édiacarien, au sud-ouest du Gondwana. Les interactions entre changements environnementaux et biodiversité sont évaluées en s'appuyant d'une part sur la composition élémentaire et isotopique des roches sédimentaires et de leur matière organique, et d'autre part sur la distribution moléculaire de biomarqueurs hydrocarbonés. Les séquences sédimentaires étudiées proviennent d'un grand bassin qui s'étend de la chaîne du Paraguay jusqu'au craton du Rio de la Plata. La séquence du Groupe Corumbâ au Sud Ouest du Brésil se situe dans la chaîne du Paraguay, tandis que le Groupe Arroyo del Soldado en Uruguay et le Groupe Sierras Bayas en Argentine sont situés sur le craton du Rio de la Plata. L'étude géochimique des sédiments des groupes Corumbâ et Sierras Bayas révèle de façon claire des conditions euxiniques dans l'océan édiacarien. On trouve ainsi, dans le Groupe Corumbâ, les biomarqueurs d'un cortège microbien anoxique et sulfurique comprenant des bactéries sulfato-réductrices, et dans les sulfures du Groupe Sierras Bayas, des enrichissements en Î4S excédant les rapports isotopiques du soufre dans le sulfate cogénétique associé aux carbonates. Dans la séquence de l'Arroyo del Soldado, un événement réducteur est mis en évidence par des teneurs plus élevées en éléments traces sensibles aux conditions redox et par des excursions négatives du 613Ccardans toutes les coupes. Cet événement affecte la totalité de la section la plus profonde et n'apparaît que dans les tempestites dans les sections les moins profondes. La persistance de valeurs négatives du ô13Ccarau large implique un gradient isotopique prononcé entre les environnements superficiels et profonds, et donc, ta présence d'une chémocline redox. Les excursions du. ôBCcar, l'enrichissement authigène en éléments traces, la présence de gammacérane et de rt-alcanes à longue chaîne, ainsi que de faibles rapports Pr/Ph et Ph/«-Cl8, viennent s'ajouter aux observations préliminaires sur la sédimentologie et la paléontologie pour indiquer que la chimie de l'océan était fortement contrôlée par la disponibilité d'oxygène, les eaux étant modérément oxiques à la surface et anoxiques en profondeur pendant la plus grande partie du Néoprotérozoïque. La stratification de la colonne d'eau était favorable au stockage de grandes quantités de nutriments dans l'océan profond. Dans les zones d'upwelling, la migration d'eaux profondes riches en nutriment vers la surface a pu provoquer une bioproductivité prononcée dans les eaux de surface. La conservation du carbone organique était assurée par les conditions anoxiques prévalant au fond. Les excursions du A13Ccar.kt.r pourraient aussi refléter des changements dans la biomasse primaire. Le présent travail apporte donc de nouvelles preuves qu'un océan stratifié s'est maintenu à la suite des glaciations néoprotérozoïques dans le Sud Ouest du Gondwana. L'association d'un océan stratifié et de l'apparition de la vie animale est en accord avec le modèle stipulant que l'évolution de la vie est associée à une meilleure oxygénation des environnements de surface. Résumé pour le grand public La période Ediacarienne (635 à -543 Ma) à la fin du Précambrien est l'une de plus énigmatiques dans l'histoire de la Terre, car elle est caractérisée par la diversification de la vie multicellulaire (eucaryote) pendant un intervalle de glaciations extrêmes. Dans ce travail de thèse, nous cherchons à déceler l'existence éventuelle d'un lien entre ces changements environnementaux et l'évolution de la vie eucaryote à travers une étude biogéochimique. La biogéochimie est l'étude des activités biologiques dans la géosphère, telles que celles intervenant dans les cycles des éléments chimiques (y compris les isotopes stables) et celles de production de composés carbonés caractérisant certains groups d'organismes ou taxons. La recherche des signatures paléoenvironnementales dans les roches précambriennes a été fortement facilitée par l'utilisation des biomarqueurs ou fossiles moléculaires. Ces composés, provenant des lipides biologiques (molécules avec des fonctions spécifiques dans les organismes), peuvent être reliés à des taxons spécifiques ou à des voies métaboliques. La transformation d'un biolipide en fossile moléculaire intervient lorsque des restes organiques déposés dans un substrat subissent un enfouissement et une augmentation de la pression (diagenèse). Ce processus mène à la formation de kérogène, un grand agrégat chimique de matière organique insoluble dans des solvants organiques, et de bitume ou fraction soluble (extractible) de la matière organique. L'analyse intégrée du kérogène et du bitume fournit des indications précieuses pour les reconstitutions paléoenvironnementales. Des conditions paléoenvironnementales ont ainsi été déterminées pour une plateforme marine Ediacarienne située dans la partie sud-américaine du bloc occidental du paléocontinent Gondwana. Les séquences sédimentaires étudiées appartiennent au même bassin qui s'étend de la ceinture du Paraguay (Groupe Corumbâ, Brésil) au craton du Rio de la Plata (Groupes Arroyo del Soldado, Uruguay et Sierras Bayas, Argentina). Nous nous sommes intéressés aux isotopes stables de carbonates et de la matière organique associée (kérogène et bitume), aux éléments majeurs et traces, ainsi qu'aux biomarqueurs caractérisant ces roches. Les résultats de cette dissertation suggèrent qu'au cours de l'Édiacarien, suite aux glaciations néoprotérozoïques dans le bloc occidental du Gondwana, l'océan était stratifié en zones spécifiques d'eaux riches en sulfures et dépourvues d'oxygène (euxiniques). L'association d'un océan stratifié et de l'apparition de la vie animale est en accord avec le modèle stipulant que l'évolution de la vie est associée à une meilleure oxygénation des environnements de surface. Les excursions isotopiques (tendance à des valeurs positives ou négatives) en constante fluctuation pour le carbone et très positives pour le soufre des sulfures, l'enrichissement en éléments trace et la présence de certains composés (e.g. gammacerane; Pr/Ph et Ph/«-Ci8 en basse proportion) conjugués aux observations sédimentologiques et paléontologiques des différents profils étudiés indiquent que la chimie de l'océan était fortement contrôlée par la disponibilité d'oxygène, avec des eaux modérément oxygénées en surface et euxiniques en profondeur pour la plupart du Néoprotérozoïque.

Petrology, geochemistry and geodynamic implications of Jurassic island arc magmatism as revealed by mafic volcanic rocks in the Mesozoic low-grade sequence, eastern Rhodope, Bulgaria

In the eastern Bulgarian Rhodope, mafic extrusive rocks and underlying greenschists are found in the Mesozoic low-grade unit, which represents the northern extension of similar sequences including the Evros ophiolites in Thrace (Greece). Both rock types define a suite of low-Ti tholeiitic basalts to transitional boninitic basaltic andesites and andesites and associated metapyroclastites (greenschists), intruded at its base by diorite dikes of a boninitic affinity. Mafic lavas and greenschists display large ion lithophile element (LILE) enrichment relative to high-field strength elements (HFSE), flat REE patterns of a slight light REE depletion, a strong island arc tholeiite (IAT) and weak MORB-like signature. All these rocks are characterized by negative Nb anomalies ascribed to arc lavas. They have positive epsilon Nd(i) values in the range of +4.87 to +6.09, approaching the lower limit of MORB-like source, and relatively high ((207)Pb/(204)Pb)(i) (15.57-15.663) at low ((206)Pb/(204)Pb)(i) (18.13-18.54) ratios. The Nd isotopic compositions coupled with trace element data imply a dominantly depleted MORB-like mantle source and a contribution of subduction modified LILE-enriched component derived from the mantle wedge. The diorite dike has a low eNdi value of -2.61 and is slightly more Pb radiogenic ((207)Pb/(204)Pb)(i) (15.64) and ((206)Pb/(204)Pb)(i) (18.56), respectively, reflecting crustal contamination. Petrologic and geochemical data indicate that the greenschists and mafic extrusive rocks represent a magmatic assemblage formed in an island arc setting. The magmatic suite is interpreted as representing an island arc-accretionary complex related to the southward subduction of the Meliata-Maliac ocean under the supra-subduction back-arc Vardar ocean/island arc system. Magmatic activity appears to have initiated in the north during the inception of the island arc system by the Early-Middle Jurassic time in the eastern Rhodope that most likely graded to back-arc spreading southwards as represented by the Late Jurassic MORB-type Samothraki Island ophiolites. This tectonic scenario is further constrained by paleotectonic reconstructions. The arc-trench system collided with the Rhodope in the Late Jurassic times. (c) 2007 Elsevier B.V. All rights reserved.

Secular trends in height and weight among children and adolescents of the Seychelles, 1956-2006.

BACKGROUND: Height of individuals has long been considered as a significant index of nutrition and health of a population; still, there is little information regarding the trends of height and weight among developing or transitional countries. We assessed the secular trends in height and weight in children of the Seychelles, a rapidly developing island state in the Indian Ocean (African region). METHODS: Height and weight were measured in all students of all schools in four selected school grades (kindergarten, 4th, 7th and 10th grades) for the periods 1998-9 (6391 children) and 2005-6 (8582 children). Data for 1956-7 was extracted from a previously published report. RESULTS: At age 15.5 years, boys/girls were on average 10/13 cm taller and 15/9 kg heavier in 2005-6 than in 1956-7. Height increased in boys/girls by 1.62/0.93 cm/decade between 1956-7 and 1998-9 and by 1.14/1.82 cm/decade between 1998-9 and 2005-6. For weight, the linear increase in boys/girls was 1.38/1.10 kg/decade between 1956-7 and 1998-9 and 2.21/2.50 kg/decade between 1998-9 and 2005-6. Overall, the relative increase in weight between 1956-7 and 2005-6 was 5-fold higher than the relative increase in height. CONCLUSION: Height and weight increased markedly over time in children aged <16 years in the Seychelles, consistent with large changes in socio-economic and nutritional indicators in the considered 50-year interval. The markedly steeper increase in weight than height over time is consistent with an epidemic of overweight and obesity.

Dominant human CD8 T cell clonotypes persist simultaneously as memory and effector cells in memory phase.

The adaptive immune system plays a critical role in protection at the time of secondary infection. It does so through the rapid and robust reactivation of memory T cells which are maintained long-term, in a phenotypically heterogeneous state, following their primary encounter with Ag. Although most HLA-A*0201/influenza matrix protein(58-66)-specific CD8 T cells from healthy donors display characteristics typical of memory T cells, through our extensive phenotypic analysis we have further shown that up to 20% of these cells express neither the IL-7 receptor CD127 nor the costimulatory molecule CD28. In contrast to the majority of CD28(pos) cells, granzyme B and perforin were frequently expressed by the CD28(neg) cells, suggesting that they are effector cells. Indeed, these cells were able to kill target cells, in an Ag-specific manner, directly ex vivo. Thus, our findings demonstrate the remarkable long-term persistence in healthy humans of not only influenza-specific memory cells, but also of effector T cells. We further observed that granzyme B expression in influenza-specific CD8 T cells paralleled levels in the total CD8 T cell population, suggestive of Ag-nonspecific bystander activation. Sequencing of TCR alpha- and beta-chains showed that the TCR repertoire specific for this epitope was dominated by one, or a few, T cell clonotype per healthy donor. Moreover, our sequencing analysis revealed, for the first time in humans, that identical clonotypes can coexist as both memory and effector T cells, thereby supporting the principle of multipotent clonotypic differentiation.

Basil conservation affected by cropping season, harvest time and storage period

Fresh basil (Ocimum basilicum L.) is used in food, phytotherapic industry, and in traditional therapeutic, due to its essential oil content and composition. Nevertheless basil can not be kept for long periods after harvest and its quality can be reduced. This work aimed to assess the influence of the season and harvest time in the postharvest conservation of basil stored for different periods. Basil was harvested at 8 am and 4 pm both in August/1999 and January/2000. Cuttings were conditioned in PVC packages and stored for 3, 6, and 9 days. During storage, chlorophyll content, essential oil content and composition were determined as well as microbiological analyses were carried out. Harvest season and the days of storage influenced the final content of essential oil. There was a linear decrease in the content of essential oil, in the chlorophyll content and in the number of mold and yeast colonies during storage. There was no effect of cropping season or harvest hour on essential oil composition, but the eugenol and linalool content increased during storage. Coliforms were under 0.3 MPN g-1 and the number of Staphylococcus aureus was under 1.0x10² UFC g-1.