La sédimentation dans le Golfe de Cadix, de Gibraltar au Cap Saint-Vincent, est soumise à la circulation d’un flux permanent d’eau profonde venant de la Méditerranée connu sous le nom de Veine d’Eau Méditerranéenne ou VEM. Cette eau plus chaude, plus salée et plus dense que les eaux atlantiques s’écoule sur les marges espagnole et portugaise avec un débit moyen aussi important queplusieurs fleuves du globe. Ce courant de fond entraîne le transport et le remaniement des particules déjà déposées sur le fond. L’étude biostratigraphique détaillée à partir du sens d’enroulement de l’espèce de foraminifère planctonique Globorotalia truncatulinoides, de l’espèce polaire Neogloquadrina pachyderma senestre et du ptéropode Limacina retroversa calibrée par de nombreuses datations 14C AMS et des analyses isotopiques a permis de corréler les carottes. Les variations des processus sédimentaires dans le temps et dans l’espace montrent l’influence du climat sur les variations des taux de sédimentation et la granularité des dépôts. Ainsi, deux périodes de moindre activité de la VEM se situent pendant le Bølling-Alleröd et l’Holocène inférieur. Le Younger Dryas traduit au contraire une période de forte circulation de la VEM. De nombreux hiatus sédimentaires et dépôts gravitaires (glissements, turbidites) traduisent une instabilité sédimentaire liée à la fréquence des tremblements de terre qui se produisent dans le Golfe de Cadix et dans les régions adjacentes. Huit types de traces fossiles ont été reconnus (Chondrites, Diplocraterion, Nereites, Paleophycus, Phycosiphon, Thalassinoides, Zoophycos, des filaments (Trichichnus et Mycelia) et des traces restent indéterminées. Les traces fossiles de Zoophycos et de Paleophycus pendant le LGM traduisent la présence de circulations de masses d’eaux riches en oxygène au niveau du fond. Ces traces fossiles de Zoophycos sont visibles du LGM à l’Holocène inférieur au niveau du chenal-levée de Tasyo. / Sedimentation in the Gulf of Cadiz from Gibraltar Strait to Cape Saint Vincent is submitted to a permanent deep water flux coming from the Mediterranean Sea and called the Mediterranean Outflow Water (MOW). This hotter and saltier water is denser that the Atlantic waters and flows along the Spanish and Portuguese margins with an average discharge as large as the discharge of several world rivers. This bottom current generates the transport and the remolding of already deposited particles. The detailed biostratigraphic study using the coiling direction of planktonic foraminifer species Globorotalia truncatulinoides, of polar specie Neogloquadrina pachyderma sinistral and of pteropod Limacina retroversa and calibrated by numerous 14C AMS dating and stable isotope analysis allowed to correlate sediment cores. Variation of sedimentary processes in time and space shows the impact of climate on sedimentation rates and sediment grain size. Two periods of lesser activity of the MOW are identified during the Bölling-Alleröd and early Holocene. Conversely, the Younger Dryas shows a higher activity of the MOW. Numerous sedimentary hiatuses and mass flow deposits (slumps, turbidites) suggest sedimentary instabilities related to the frequent earthquakes that are initiated in the Gulf of Cadiz and neighboring areas. Height types of fossil traces have been identified (Chondrites, Diplocraterion, Nereites, Paleophycus, Phycosiphon, Thalassinoides, Zoophycos, filaments (Trichichnus and Mycelia) and undetermined traces. Fossil traces of Zoophycos and Paleophycus during the LGM show the activity of oxygen-rich water flowing along the seafloor. Fossil traces of Zoophycos are identified from LGM to lower Holocene in the Tasyo channel-levee.

Il est généralement admis que les sources carolingiennes, issues en majorité de l'Europe septentrionale, ne s'intéressent guère à la Méditerranée. A la suite d'Henri Pirenne, certains ont même voulu justifier à l'aide de l'expansion de l'Islam la désertion de l'ancien Mare Nostrum par les Occidentaux, qui aurait été à l’origine du développement de l'Europe rhénane. Il est pourtant frappant de constater que les premiers siècles de la dynastie carolingienne correspondent à un mouvement de conquêtes franques sans précédent en direction du sud. A la mort de Charlemagne, l'Empire contrôle même plus de 1500 km de côtes méridionales, de Barcelone jusqu'à Rome, et tente d’étendre son influence sur les îles proches, comme la Corse et l'archipel des Baléares. Dès lors, les formes de la présence franque au Sud suscitent autant de questionnements que le relatif désintérêt dont celle-ci a fait l'objet jusqu'à ce jour. L'étude de ces marges révèle pourtant leur importance dans la construction impériale ainsi que leur singularité dans l'Occident franc. Elle montre aussi le caractère décisif bien que longtemps sous-évalué de l'expansion carolingienne pour l'histoire médiévale du bassin méditerranéen / It's usually accepted that Carolingian sources, as most of them come from Northern Europe, aren't very interested in Mediterranean issues. Since Henri Pirenne's Mohammed and Charlemagne (1937), some scholars explained the reason of such ignorance by the rise of Islam, which would have forbidden the former Mare Nostrum to Western Europeans and would have been the only cause of the economic growth of the Seine and Rhine valleys. It's nevertheless striking that the first centuries of the Carolingian dynasty is actually linked with an important expansion toward Gaul's southern shores. When Charlemagne died, his empire even ruled almost 1500 km of Mediterranean coasts, from Barcelona to Rome, and was trying to keep control of near islands, as Corsica or the Balearic archipelago. The features of Frankish domination over such territories is therefore questioning, as well as it shows the importance, largely underestimated up to this day, of the Carolingian expansion for the mediaeval history of the Mediterranean sea.

Les modèles pluie-débit sont des outils essentiels pour de nombreuses applications hydrologiques, notamment la prévision des crues. L’objet de cette thèse est d’examiner les performances d’un modèle événementiel distribué, dont l’intérêt est de résumer la représentation des processus à la phase de crue, et la condition initiale à un indice de saturation du bassin facilement observable ou accessible. Ce dernier dispense de modéliser la phase inter-crue, et simplifie la paramétrisation et le calage du modèle. Le modèle étudié combine une fonction de production type SCS et une fonction de transfert type lag and route, appliquées à une discrétisation du bassin en mailles carrées régulières.Le modèle est d’abord testé sur le bassin versant du Real Collobrier. Ce bassin méditerranéen est suivi depuis plus de 50 ans par l’IRSTEA, et dispose d’une exceptionnelle densité de mesures de pluies et de débits. Cet environnement favorable permet de limiter les incertitudes sur l’estimation des pluies et d’évaluer les performances intrinsèques du modèle. Dans ces conditions, les crues sont bien reconstituées à l’aide d’un jeu de paramètres unique pour l’ensemble des épisodes testés, à l’exception de la condition initiale du modèle. Celle-ci apparaît fortement corrélée avec l’humidité du sol en début d’épisode, et peut être prédéterminée de façon satisfaisante par le débit de base ou l’indice w2 fourni par le modèle SIM de Météo-France. Les performances du modèle sont ensuite étudiées en dégradant la densité des pluviomètres, et rendent compte du niveau de performances du modèle dans les cas que l’on rencontre le plus souvent. .La variabilité spatiale des paramètres du modèle est étudiée à l’échelle de différents sous-bassins du Real Collobrier. La comparaison a permis de mettre en évidence et de corriger un effet d’échelle concernant l’un des paramètres de la fonction de transfert. Les relations entre la condition initiale du modèle et les indicateurs d’humidités des sols en début d’épisode restent bonnes à l’échelle des sous-bassins, mais peuvent être significativement différentes selon les sous-bassins. Une seule relation ne permet pas de normaliser l’initialisation du modèle sur l’ensemble des sous-bassins, à une échelle spatiale de quelques km2 ou dizaines de km2. Dans le cas de l’indice d’humidité du sol w2, une explication possible est que cet indice ne prend pas en compte suffisamment finement les propriétés des sols. Enfin, la variabilité spatiale des paramètres du modèle est étudiée à l’échelle d’un échantillon d’une quinzaine de bassins méditerranéens de quelques centaines de km2, associés à des paysages et des fonctionnements hydrologiques divers. La comparaison montre qu’à cette échelle, le lien entre les indicateurs de saturation du bassin et la condition initiale peut rester stable par type de bassin, mais varie significativement d’un type de bassin à l’autre. Des pistes sont proposées pour expliquer cette variation.En conclusion, ce modèle événementiel distribué représente un excellent compromis entre performances et facilité de mise en œuvre. Les performances sont satisfaisantes pour un bassin donné ou pour un type de bassin donné. L’analyse et l’interprétation de la variabilité spatiale des paramètres du modèle apparaît cependant complexe, et doit faire l’objet du test d’autres indicateurs de saturation des bassins, par exemple mesures in situ ou mesures satellitaires de l’humidité des sols. / Rainfall-runoff models are essential tools for many hydrological applications, including flood forecasting. The purpose of this thesis was to examine the performances of a distributed event model for reproducing the Mediterranean floods. This model reduces the parametrization of the processes to the flood period, and estimates the saturation of the catchment at the beginning of the event with an external predictor, which is easily observable or available. Such predictor avoids modelling the inter-flood phase and simplifies the parametrization and the calibration of the model. The selected model combines a distributed SCS production function and a Lag and Route transfer function, applied to a discretization of the basin in a grid of regular square meshes.The model was first tested on the Real Collobrier watershed. This Mediterranean basin has been monitored by IRSTEA for more than 50 years and has an exceptional density of rainfall and flow measurements. This favourable environment made it possible to reduce the uncertainties on the rainfall input and to evaluate the actual performances of the model. In such conditions, the floods were correctly simulated by using constant parameters for all the events, but the initial condition of the event-based model. This latter was highly correlated to predictors such as the base flow or the soil water content w2 simulated by the SIM model of Meteo-France. The model was then applied by reducing the density of the rain gauges, showing loss of accuracy of the model and biases in the model parameters for lower densities, which are representative of most of the catchments.The spatial variability of the model parameters was then studied in different Real Collobrier sub-basins. The comparison made it possible to highlight and correct the scale effect concerning one of the parameters of the transfer function. The catchment saturation predictors and the initial condition of the model were still highly correlated, but the relationships differed from some sub-catchments. Finally, the spatial variability of the model parameters was studied for other larger Mediterranean catchments, of which area ranged from some tenth to hundreds of square kilometres. Once more, the model could be efficiently initialized by the base flow and the water content w2, but significant differences were found from a catchment to another. Such differences could be explained by uncertainties affecting as well the rainfall estimation as the selected predictors. However, the relationships between the initial condition of the model and the water content w2 were close together for a given type of catchment.In conclusion, this distributed event model represents an excellent compromise between performance and ease of implementation. The performances are satisfactory for a given catchment or a given type of catchment. The transposition of the model to ungauged catchment is less satisfactory, and other catchment saturation indicators need to be tested, e.g. in situ measurements or satellite measurements of soil moisture.

Le bassin méditerranéen est reconnu comme un "point chaud" de biodiversité soumis à de fortes pressions anthropiques. En domaine marin, les habitats coralligènes participent grandement à cette biodiversité et leur situation côtière les rend accessibles aux hommes. La thèse porte sur l'identification et l'évaluation de leurs services écosystémiques. J’ai utilisé le concept de \textit{service écosystémique} à une échelle locale : la Baie de Marseille (anthropisée) et le Parc national de Port-Cros (sous pression humaine minimale). Le premier volet de la thèse porte sur l'identification et la description des services rendus par les habitats coralligènes dans les zones d’étude. Les services les plus évidents (production de ressource alimentaire, production de corail rouge et sites de plongée) font l’objet d’une étude plus approfondie. Le deuxième volet de la thèse teste le concept de cascade de service écosystémique d'Haines-Young et Potschin pour décrire les éléments et fonctions de l'écosystème impliqués dans chaque service, les bénéficiaires et les types de valeurs économiques qui en sont issus, et des indicateurs pour mesurer chaque niveau de la cascade. Le troisième volet de la thèse porte sur une analyse de l'activité de plongée sur les habitats coralligènes de la baie de Marseille. Le dernier volet de la thèse est une étude des préférences déclarées dans les secteurs de Marseille et Port-Cros concernant les services rendus par les habitats coralligènes, grâce à la méthode des choix discrets. Ce dernier volet comprend une étude de l’impact de la connaissance initiale et de l’apport d’information dans la formation des préférences. / The Mediterranean basin is recognized as a "hotspot" of biodiversity subjected to strong anthropic pressures. In the marine domain, coralligenous habitats greatly contribute to the basin’s biodiversity and their coastal location makes them accessible to humans. The thesis attempts to identify and economically evaluate some of those ecosystem services. I used the concept of \textit{ecosystem service} at a local scale, focusing on the Bay of Marseille (anthropized) and the Port-Cros national park (under minimal human pressure). The first part of the thesis deals with the identification and description of the services rendered by coralligenous habitats in the study areas. The second part of the thesis describes the provisionning services through the application of the concept of ecosystem service cascade as developed by Haines-Young and Potschin. This approach helps to identify the elements and functions of the ecosystem involved in each service, the human beneficiaries and the types of economic benefits associated with the services. This chapter also proposes variables to measure each level of the cascade. The third part of the thesis deals with an analysis of the relationship between the presence of coralligenous habitat and the frequency of dives in the Bay of Marseille. The last part of the thesis employs the method of discrete choices experiment to study the declared preferences in the study areas of Marseille and Port-Cros concerning the services rendered by the coralligenous habitats. This analysis provided insight into how preferences can evolve as initial knowledge is enhanced through the provision of additional information.

Une trace est une suite d’empreintes, laissées par le passage d’un être ou d’un objet – c’est donc avant tout l’indice d’un chemin parcouru. C’est à ce déplacement dans le temps et dans l’espace qu’invitent mes travaux de recherche dont l’objectif est de suivre Edith Wharton « à la trace ». La trace, c’est d’abord, pour ce qu’elle nous apprend sur le voyageur et son rapport au monde, cette croisière en Méditerranée qu’elle entreprend en 1888 à bord du Vanadis. C’est également l’empreinte qui subsiste de cette expérience du voyage : un manuscrit dactylographié qui retrace le périple et rend compte du rapport particulier d’Edith Wharton à l’écriture.La trace – ce qu’on suit (« suivre à la trace ») – renvoie donc à une double activité : d’une part au voyage lui-même, d’autre part, à l’exploration de toutes les pistes que j’ai cru bon d’ouvrir à partir du document originel : sur la vie et l’œuvre d’Edith Wharton, sur son environnement socio-culturel et sur le genre de la littérature de voyage – toute une série d’empreintes, donc de signes conduisant à de nombreux signifiés. La question demeure toujours, en dernier ressort, de savoir si les signifiés que croit avoir découvert le chercheur sont bien ceux de l’écrivain. / A trace is both a material imprint and a trail or series of imprints, marking the passage of a being or an object in transit; it can therefore be understood as the material evidence of a path that has been pursued. In the particular context of this research, the term trace refers first and foremost to the record of a sea voyage. This unpublished journal, kept by Edith Wharton, gives an account of the various stages of the Mediterranean cruise she made in the yacht, the Vanadis, in the spring of 1888.This long book is of particular interest, insofar as it, not only gives a fascinating account of the response of a young nineteenth-century cultivated American to the different cultures discovered in the course of a voyage leading her from North Africa to the Greek Islands and the shores of the Adriatic, but also provides valuable insight into the early responses of an artist in the making.The term “trace” therefore refers to both these aspects: first the voyage itself, the places visited, their physical features and historical significance; secondly the traces left by the visitor who embarked on this adventure at a turning point in her life. The sentiment that the future artist is poised at the crossroads of her existence, leads the researcher – in an attempt to leave as few stones as possible unturned – on a trail leading back to her past and forward to her future. This investigation would not be complete without a survey of travel literature, as the particular genre Edith Wharton has chosen as her means of expression. All these traces unite to form a series of “signs” (in the Saussurian sense of the word), which the researcher endeavours to interpret in the hopes of understanding what is “signified” on a deeper level.

<p>Techniques used in the building of a number of ships from the Mediterranean will be presented in this paper. The two techniques thnat will be discussed are shell-based technique and skeleton-basedtechnique. An attempt to clearify and delineate the transition between these two techniques will be made. The possible reasons for transition will then be described and discussed. The development ofthe techniques is going to be identified with help from four wrecks by analyzing their edge joineriesand this facts will be used as a basis for a chronological presentation. Finally, data from theanalyzed wrecks will be compared and the results are interpreted in the text.</p>

In this work, we implemented the GHER hydrodynamic model in the Gulf of Lions (resolution 1/100°). This model is nested interactively in another model covering the North-Western basin of the Mediterranean Sea (resolution 1/20°), itself nested in a model covering the whole basin (1/4°). A data assimilation filter, called the SEEK filter, is used to test in which of those grids observations taken in the Gulf of Lions are best assimilated. Therefore, twin experiments are used: a reference run is considered as the truth, and another run, starting from different initial conditions, assimilates pseudo-observations coming from the reference run. It appeared that, in order to best constrain the coastal model, available data should be assimilated in that model. The most efficient setup, however, is to group all the state vectors from the 3 grids into a single vector, and hence coherently modify the 3 domains at once during assimilation cycles. Operational forecasting with nested models often only uses so-called passive nesting: no data feedback happens from the regional models to the global model. We propose a new idea: to use data assimilation as a substitute for the feedback. Using again twin experiments, we show that when assimilating outputs from the regional model in the global model, this has benecial impacts for the subsequent forecasts in the regional model. The data assimilation method used in those experiments corrects errors in the models using only some privileged directions in the state space. Furthermore, these directions are selected from a previous model run. This is a weakness of the method when real observations are available. We tried to build new directions of the state space using an ensemble run, this time covering only the Mediterranean basin (without grid nesting). This led to a quantitative characterization of the forecast errors we might expect when various parameters and external forcings are affected by uncertainties. Finally, using these new directions, we tried to build a statistical model supposed to simulate the hydrodynamical model using only a fraction of the computer resources needed by the latter. To achieve this goal, we tried out artifficial neural networks, nearest-neighbor and regression trees. This study constitutes only the first step toward an innovative statistical model, as in its present form, only a few degrees of freedom are considered and the primitive equation model is still required to build the AL method. We tried forecasting at 2 different time horizons: one day and one week.

Diagenetic studies of carbonate rocks focused for a long time on photozoan carbonate assemblages deposited in tropical climates. The results of these investigations were taken as models for the diagenetic evolution of many fossil carbonates. Only in recent years the importance of heterozoan carbonates, generally formed out of the tropics or in deeper waters, was realized. Diagenetic studies focusing on this kind of rocks are still scarce, but indicate that the diagenetic evolution of these rocks might be a better model for many fossil carbonate settings ("calcite-sea" carbonates) than the photozoan model used before.<br><br> This study deals with the determination of the diagenetic pathways and environments in such shallow-water heterozoan carbonate assemblages. Special emphasis is put on the identification of early, near-seafloor diagenetic processes and on the evaluation of the amount of constructive diagenesis in form of cementation in this diagenetic environment.<br><br> As study area the Central Mediterranean, the Maltese Islands and Sicily, was chosen. Here two sections were logged in Olio-Miocene shallow-water carbonates consisting of different kinds of heterozoan assemblages. The study area is very suitable for the investigation of constructive early diagenetic processes, as the rocks were never deeply buried and burial diagenetic pressure solution and cementation as cause of lithification could be ruled out. Nevertheless, the carbonate rocks are well lithified and form steep cliffs, implying cementation/lithification in another, shallower diagenetic environment. To determine the diagenetic pathways and environments, detailed transmitted light and cathodoluminescence petrography was carried out on thin sections. Furthermore the stable isotope (δ¹⁸O and δ¹³C) composition of the bulk rock, single biota and single cement phases was determined, as well as the major and trace element composition of the single cement phases.<br><br> Petrographically three (Sicily) to four (Maltese Islands) cementation phases, two phases of fabric selective and one of non-fabric selective dissolution, one phase of neomorphism and one of chemical compaction could be distinguished. The stable isotope measurements of the single cement phases pointed to cement precipitation from marine, marine-derived and meteoric waters. The trace element analysis indicated precipitation under reducing conditions, (A) in an open system with low rock-water interaction on the Maltese Islands and (B) in a closed system with high rock-water interaction on Sicily. For the closed systems case, aragonite as cement source could be concluded because its chemical composition was preserved in the newly formed cements.<br><br> By integrating these results, diagenetic pathways and environments for the investigated locations were established, and the cement source(s) in the different environments were determined. The diagenetic evolution started in the marine environment with the precipitation of fibrous/fibrous-bladed and epitaxial cement I. These cements formed as High Mg Calcite (HMC) directly out of marine waters. The paleoenvironmentally shallowest part of the section on the Maltese Islands was also exposed to meteoric diagenetic fluids. This meteoric influence lead to the dissolution of aragonitic and HMC skeletons, which sourced the cementation by Low Mg Calcitic (LMC) epitaxial cement II in this part of the Maltese section. Entering the burial-marine environment the main part of dissolution, cementation and neomorphism started to take place. The elevated CO2 content in this environment, caused by the decay of organic matter, lead to the dissolution of aragonitic skeletons, which sourced the cementation by LMC epitaxial cement II, bladed and blocky cements. The earlier precipitated HMC cement phases were either partly dissolved (epitaxial cement I) or neomorphosed to LMC (fibrous/fibrous-bladed and epitaxial cement I). In the burial environment weak chemical compaction took place without sourcing significant amounts of cementation. In a last phase the rocks entered the meteoric realm by uplift, which caused non-fabric selective dissolution. This study shows that early diagenetic processes, taking place at or just below the sediment-water-interface, are very important for the mineralogical stabilization of heterozoan carbonate strata. The main amount of constructive diagenesis in form of cementation takes place in this environment, sourced by dissolution of aragonitic and, to a lesser degree, of HMC skeletons.<br><br> The results of this study imply that the primary amount of aragonitic skeletons in heterozoan carbonate sediments must be carefully assessed, as they are the main early diagenetic cement source. In fossil heterozoan carbonate rocks, aragonitic skeletons might be the cement source even when no relict structures like micritic envelops or biomolds are preserved. In general, the diagenetic evolution of heterozoan carbonate rocks is a good model for the diagenesis of "calcite-sea" time carbonate rocks. / Diagenetische Untersuchungen an Karbonatgesteinen beschränkten sich lange Zeit auf photozoische Karbonatvergesellschaftungen der tropischen Breiten. Die Ergebnisse dieser Untersuchungen wurden als modellhaft für den Diageneseverlauf vieler Karbonatgesteine angesehen. Erst in den letzten Jahren wurde die Bedeutung heterozoischer Karbonatvergesellschaften, die sich im Allgemeinen außerhalb der Tropen oder in tieferem Wasser bilden, erkannt. Diagenetische Untersuchungen an dieser Art von Karbonatgesteinen sind immer noch selten, deuten aber an, dass der Diageneseverlauf in diesen Karbonaten ein besseres Model für viele fossile Karbonatgesteine ("Calcit-Meer"-Karbonate) darstellt als das bisher benutzte photozoische Diagenesemodel. Ziel dieser Studie war die Bestimmung des Diageneseverlaufs in solch flachmarinen Karbonaten mit heterozoischer Biogenvergesellschaftung. Die Milieus, in denen die diagenetischen Veränderungen stattfanden, sollten bestimmt werden. Besonderes Augenmerk lag auf der Art und Menge von Veränderungen, die frühdiagenetisch, nahe dem Meeresboden, stattfanden. Dabei war vor allem der Anteil an konstruktiver Diagenese in Form von Zementation von Interesse.<br><br> Das Arbeitsgebiet wurde im zentralen Mittelmeerraum gewählt und befindet sich auf den Maltesischen Inseln und Sizilien. Hier wurden zwei Profile in Flachwassserkarbonaten oligo-miozänen Alters aufgenommen, die sich aus unterschiedlichen heterozoischen Biogenvergesellschaftungen zusammensetzen. Dieses Arbeitsgebiet ist für die Untersuchung konstruktiver frühdiagenetischer Prozesse besonders geeignet, da die Gesteinsabfolgen niemals tief versenkt wurden und versenkungsdiagenetisch bedingte Drucklösung und Zementation als Ursache für die Lithifizierung ausgeschlossen werden können. Trotzdem sind die untersuchten Karbonatgesteine gut verfestigt und bilden steile Kliffs, was auf Zementation/Verfestigung in einem anderen, flacheren Diagenesemilieu hinweist. Zur Bestimmung der Diageneseabfolge und der diagenetischen Milieus wurden detaillierte petrographische Untersuchungen im Durchlicht und mit Kathodolumineszenz an Dünnschliffen durchgeführt. Außerdem wurden die Verhältnisse der stabilen Isotope δ¹⁸O und δ¹³C am Gesamtgestein, an einzelnen Biogenen und an einzelnen Zementphasen bestimmt. Die Haupt- und Spurenelement Zusammensetzung (Ca, Mg, Fe, Mn und Sr) wurde an den einzelnen Zementphasen ermittelt.<br><br> Petrographisch lassen sich drei (Sizilien), beziehungsweise vier (Maltesische Inseln) Zementationsphasen, zwei Phasen von materialabhängiger und eine Phase von materialunabhängiger Lösung, sowie eine Phase von Neomorphismus und eine chemische Kompaktionsphase unterscheiden. Die Messungen der stabilen Isotopenverhältnisse an den einzelnen Zementphasen deuten auf Zementausfällung aus marinen und meteorischen Wässern sowie aus Fluiden marinen Ursprungs hin. Die Spurenelementanalyse lässt außerdem auf Zementausfällung unter reduzierenden Bedingungen schließen. Diese fand einerseits, im Falle der Maltesischen Inseln, in einem offenen System mit geringer Gesteins-Wasser-Interaktion, andererseits, im Falle von Sizilien, in einem geschlossenen System mit großer Gesteins-Wasser-Interaktion statt. Bei der Zementation in einem geschlossenen System konnte Aragonit als Zementquelle bestimmt werden, da seine charakteristische chemische Zusammensetzung im neu gebildeten Zement erhalten blieb.<br><br> Durch die Integration aller Ergebnisse konnten für die beiden Lokalitäten die Diageneseabfolgen und die diagenetischen Milieus sowie die Zementquelle(n) in diesen Milieus bestimmt werden. Die diagenetische Entwicklung begann im marinen Milieu mit der Ausfällung von fibrösem bis fibrös-blättrigem und epitaxialem Zement I. Diese Zemente wurden als Hoch Magnesium Calcit (HMC) direkt aus marinem Wasser ausgefällt. Die paläogeographisch flachsten Abschnitte des Profils auf den Maltesischen Inseln gelangten dann unter den Einfluss meteorischer Wässer. Dieser meteorische Einfluss führte zur Lösung von aragonitischen und HMC Schalen, was die Zementation mit Niedrig (Low) Magnesium Calcitischem (LMC) epitaxialem Zement II in diesem Profilabschnitt speiste. Im marinen Versenkungsmilieu fand anschließend der Hauptteil an Lösung, Zementation und Neomorphismus statt. Der erhöhte CO2-Gehalt in diesem Milieu, verursacht durch den Zerfall von organischem Material, führte zur Lösung von aragonitischen Schalen, was die Zementation mit LMC epitaxialem Zement II, blättrigem und blockigem Zement speiste. Die vorher ausgefällten HMC Zementphasen wurden entweder teilweise gelöst (epitaxialer Zement I) oder in LMC umgewandelt (fibrös/fibrös-blättriger und epitaxialer Zement I). Im versenkungsdiagenetischen Milieu fand anschließend geringe chemische Kompaktion statt, ohne aber die Ausfällung von größeren Mengen an Zement zu speisen. In einer letzten Phase gelangten die Gesteine durch Hebung wieder ins meteorische Milieu, was materialunabhängige Lösungserscheinungen verursachte. Diese Untersuchung zeigt, dass frühdiagenetische Prozesse, die an der Sediment-Wasser-Grenzfläche oder knapp darunter stattfinden, sehr wichtig für die mineralogische Stabilisierung von heterozoischen Karbonatabfolgen sind. Der Hauptteil der konstruktiven Diagenese in Form von Zementation findet in diesem Milieu statt, gespeist durch die Lösung von aragonitischen und, zu einem geringern Teil, HMC Schalen.<br><br> Die Ergebnisse dieser Studie implizieren, dass der ursprünglich vorhandene Anteil an aragonitischen Schalen in heterozoischen Karbonatsedimenten sehr sorgfältig bestimmt werden muss, da diese Schalen die wichtigste frühdiagenetische Zementquelle darstellen. In fossilen heterozoischen Karbonatgesteinen können aragonitische Schalen die wichtigste Zementquelle darstellen, auch wenn keine Reliktstrukturen wie mikritische Hüllen oder Biomolds erhalten geblieben sind. Im Allgemeinen stellt der Diageneseablauf in heterozoischen Karbonaten ein gutes Modell für die Diagenese von "Calcit-Meer"-Karbonatgesteinen dar.

Germination rates and germination fractions of seeds can be predicted well by the hydrothermal time (HTT) model. Its four parameters hydrothermal time, minimum soil temperature, minimum soil moisture, and variation of minimum soil moisture, however, must be determined by lengthy germination experiments at combinations of several levels of soil temperature and moisture. For some applications of the HTT model it is more important to have approximate estimates for many species rather than exact values for only a few species. We suggest that minimum temperature and variation of minimum moisture can be estimated from literature data and expert knowledge. This allows to derive hydrothermal time and minimum moisture from existing data from germination experiments with one level of temperature and moisture. We applied our approach to a germination experiment comparing germination fractions of wild annual species along an aridity gradient in Israel. Using this simplified approach we estimated hydrothermal time and minimum moisture of 36 species. Comparison with exact data for three species shows that our method is a simple but effective method for obtaining parameters for the HTT model. Hydrothermal time and minimum moisture supposedly indicate climate related germination strategies. We tested whether these two parameters varied with the climate at the site where the seeds had been collected. We found no consistent variation with climate across species, suggesting that variation is more strongly controlled by site-specific factors. / Keimungsgeschwindigkeit und Anteil gekeimter Samen lassen sich gut mit dem Hydrothermalzeit-Modell bestimmen. Dessen vier Parameter Hydrothermalzeit, Mindesttemperatur, Mindestbodenfeuchte und Streuung der Mindestbodenfeuchte müssen jedoch durch aufwendige Keimungsversuche bei Kombinationen von mehreren Temperatur- und Feuchtigkeitsstufen bestimmt werden. Für manche Anwendungen des Hydrothermalzeit-Modells sind aber ungefähre Werte für viele Arten wichtiger als genaue Werte für wenige Arten. Wenn die Mindesttemperatur und die Streuung der Mindestfeuchte aus Veröffentlichungen und Expertenwissen geschätzt würde, können die Hydrothermalzeit und Mindestbodenfeuchte aus vorhandenen Daten von Keimungsversuchen mit nur einer Temperatur- und Feuchtigkeitsstufe berechnet werden. Wir haben unseren Ansatz auf einen Keimungsversuch zum Vergleich der Keimungsquote wilder einjähriger Arten entlang eines Trockenheitsgradienten in Israel angewendet. Mit diesem Ansatz bestimmten wir die Hydrothermalzeit und Mindestfeuchtigkeit von 36 Arten. Der Vergleich mit genauen Werten für drei Arten zeigt, dass mit unserem Ansatz Hydrothermalzeit-Parameter einfach und effektiv bestimmt werden können. Hydrothermalzeit und Mindestfeuchtigkeit sollten auch bestimmte klimabedingte Keimungsstrategien anzeigen. Deshalb testeten wir, ob diese zwei Parameter mit dem Klima am Ursprungsort der Samen zusammenhängen. Wir fanden jedoch keinen für alle Arten übereinstimmenden Zusammenhang, so dass die Unterschiede vermutlich stärker durch standörtliche als durch klimatische Ursachen hervorgerufen werden.

Case control studies have shown that a high consumption of fish, olive oil, and cooked vegetables is associated with a decreased risk of developing rheumatoid arthritis (RA). These foods have a central position in the traditional Cretan Mediterranean diet, and it has been suggested that dietary factors contribute to the low prevalence of RA in Mediterranean countries. The overall aim of this thesis was to examine whether a modified Cretan Mediterranean diet can reduce signs and symptoms of RA. This was investigated in a three-month dietary intervention trial in which 51 patients with well controlled, although active RA of at least two years duration took part. A further aim was to study the compliance with the experimental and control diets used in the study, and to validate the diet history interview method used to assess the dietary intake. The validation was carried out by means of biological markers of dietary intake. From baseline to the end of the study the group that had adopted the Cretan Mediterranean diet (MD group; n=26) obtained a reduction in disease activity, improved physical function, and improved vitality, while no changes was seen in the control diet group (CD group; n=25). According to the dietary assessments, the intake frequencies of antioxidant-rich food items increased in the MD group. This group also had a significantly higher intake of vitamin E, vitamin C and selenium compared to the CD group. Despite the reported increase in the consumption frequencies of antioxidant-rich foods, the plasma levels of carotenoids, vitamin C, lipid adjusted tocopherols, uric acid and urine malondialdehyde, a marker of oxidative stress, were unchanged at the end of the study. The plasma levels of retinol, vitamin C and uric acid were, however, correlated to indices of disease activity. Changes in the reported consumption of food groups with relevance to the fat intake were also observed in the MD group, including an increased intake of fish, shellfish and poultry, and a decreased intake of meat and high fat dairy products. As a result, the total fat intake was lower in the MD group compared to the CD group. Furthermore, in the MD group a slightly higher percentage of the energy intake was derived from polyunsaturated fatty acids and a lower percentage from saturated fatty acids. This group also had a lower ratio of n-6:n-3 fatty acids. A corresponding change in the relation between n-6 and n-3 fatty acids was also observed in s-phospholipids. The validation of the diet history interview method showed that the diet history interview could capture the dietary intake fairly well. The validity of the reported dietary intake did not differ between the MD and the CD group, which indicates that the dietary assessment was not biased by the dietary intervention.