La noblesse occidentale à la fin du Moyen Age: bilan historiographique et perspectives de recherche.

Traduction anglaise dans Nobles and Nobility in Medieval Europe. Actes du colloque de King's College Londres, 15-17 avril 1998, dir. A. Duggan, Woodbridge, 2000, p. 263-274International audienceLa recherche sur la noblesse occidentale à la fin du Moyen Age se porte bien. Partout en Europe de nombreux travaux sont pu­bliés, qui précisent notre connaissance de ce groupe social. L'his­toriographie la plus actuelle semble touchée par ce renouveau. A quelques exceptions près, toutefois, l'engouement pour l'aris­tocratie est relativement récent, et fait fi des préjugés qui s'attachaient naguère à l'histoire des élites. Il coïncide avec la décou­verte d'une histoire sociale fondée sur la prosopographie, c'est-à-dire sur l'étude biographique de maints personnages afin de les replacer dans un réseau global de parenté, de solidarité et de clientèle

A general methodology to price and hedge derivatives in incomplete markets

We introduce and discuss a general criterion for the derivative pricing in the general situation of incomplete markets, we refer to it as the No Almost Sure Arbitrage Principle. This approach is based on the theory of optimal strategy in repeated multiplicative games originally introduced by Kelly. As particular cases we obtain the Cox-Ross-Rubinstein and Black-Scholes in the complete markets case and the Schweizer and Bouchaud-Sornette as a quadratic approximation of our prescription. Technical and numerical aspects for the practical option pricing, as large deviation theory approximation and Monte Carlo computation are discussed in detail.Comment: 24 pages, LaTeX, epsfig.sty, 5 eps figures, changes in the presentation of the method, submitted to International J. of Theoretical and Applied Financ

Factors controlling the sedimentary evolution of the Kimmeridgian ramp in the north Iberian Basin (NE Spain)

The aim of this paper is to summarize the present knowledge reached by the authors on the carbonate ramp which developed in the iberian basin during Kimmeridgian times. Our results were obtained from a combined field analysis and computer modelling carried out in the north Iberian Chain (NE Spain). Extensive field analysis in the Ricia area (Zaragoza, NE Spain), resulted in a detailed mapping of the transition from inner to outerramp facies on this carbonate rampo Three facies belts may be distinguished in this rampo The outer ramp facies consists of marls and mudstones rhythmic facies. The inner ramp facies, located aboye fair-weather wave base, are dominated by coral patch reef growing. The middle ramp facies are represented by marls and micrites bearing skeletal and oolitic tempestite levels which sharply grade into high-amplitude o'olitic sandwave. Factors such as resedimentation by storms, carbonate production and relative variation of sea level acting in the Kimmeridgian ramp are also quantiphied and discussed. Most of the mud accumulated in outer-ramp areas was produced in the coral «carbonate factory» located in inner areas. Off-shore resedimentation by storm was the main agent of basinward transport of this mudo The deduced accommodation curve consists of three elements: a linear rise which satisfactorily matches the normal subsidence figures observed in intracratonic basins; a third-order cycle, that may have a regional cause and higher order cycles in the Milanckovich band, that may be eustatic in origin.La sedimentación en la cuenca ibérica septentrional durante el Kimmeridgiense tuvo lugar en una extensa rampa carbonatada de bajo ángulo. Las facies de rampa externa, acumuladas por debajo del nivel de base del oleaje debido a tormentas (i.e., C. 50 to 80 m de profundidad), están formadas por una ritmita de margas y calizas (i.e., Fm Loriguilla). Las facies de rampa interna, localizadas por encima del nivel de base del oleaje de buen tiempo (i.e., hasta 10 m de profundidad), están dominadas por bioconstrucciones de corales (i.e .. Fm Torrecilla). Las facies de rampa media están representadas por margas y micritas con niveles de tempestitas bioclásticas y oolíticas que pasan lateral y verticalmente a sandwaves oolíticos de gran amplitud (i.e., Mb. Ricia). La modelización por ordenador ha permitido cuantificar algunos aspectos de esta rampa. Así, la distancia de resedimentación mar adentro del sedimento de grano fino producido en las zonas internas de la rampa, por el efecto de tormentas, puede ser de hasta 40 Km. La producción de carbonato oscilaría entre 8 y 2 cm/l.000 años. en función de la profundidad. Por otra parte, la curva de la variación de la acomodación deducida para el Kimmeridgiense está compuesta por tres elementos: un ascenso lineal de 4 cm/l.000 años. un ciclo de tercer orden de baja amplitud y ciclos de mayor orden. de 20.000 y 100.000 años respectivamente. Tanto el ascenso lineal como el ciclo de tercer orden se han relacionado con causas regionales, mientras que los ciclos de mayor orden se encuentran en la banda de Milanckovich y pueden ser por tanto de origen eustático

Sedimentología de la Formación Calizas con oncolitos de Higueruelas (Malm) en la región de Muel-Belchite (Provincia de Zaragoza)

El estudio sedimentológico de la Formación Higueruelas (Malm) en la región de Muel-Belchite, permite definir un ciclo regresivo con gran variedad de facies y ambientes, con desarrollo en la plataforma interna de montículos algales y coralinos, y sedimentación oolítica litoral

Optimal hedging of Derivatives with transaction costs

We investigate the optimal strategy over a finite time horizon for a portfolio of stock and bond and a derivative in an multiplicative Markovian market model with transaction costs (friction). The optimization problem is solved by a Hamilton-Bellman-Jacobi equation, which by the verification theorem has well-behaved solutions if certain conditions on a potential are satisfied. In the case at hand, these conditions simply imply arbitrage-free ("Black-Scholes") pricing of the derivative. While pricing is hence not changed by friction allow a portfolio to fluctuate around a delta hedge. In the limit of weak friction, we determine the optimal control to essentially be of two parts: a strong control, which tries to bring the stock-and-derivative portfolio towards a Black-Scholes delta hedge; and a weak control, which moves the portfolio by adding or subtracting a Black-Scholes hedge. For simplicity we assume growth-optimal investment criteria and quadratic friction.Comment: Revised version, expanded introduction and references 17 pages, submitted to International Journal of Theoretical and Applied Finance (IJTAF

Macroscopic chaos in globally coupled maps

We study the coherent dynamics of globally coupled maps showing macroscopic chaos. With this term we indicate the hydrodynamical-like irregular behaviour of some global observables, with typical times much longer than the times related to the evolution of the single (or microscopic) elements of the system. The usual Lyapunov exponent is not able to capture the essential features of this macroscopic phenomenon. Using the recently introduced notion of finite size Lyapunov exponent, we characterize, in a consistent way, these macroscopic behaviours. Basically, at small values of the perturbation we recover the usual (microscopic) Lyapunov exponent, while at larger values a sort of macroscopic Lyapunov exponent emerges, which can be much smaller than the former. A quantitative characterization of the chaotic motion at hydrodynamical level is then possible, even in the absence of the explicit equations for the time evolution of the macroscopic observables.Comment: 24 pages revtex, 9 figures included. Improved version also with 1 figure and some references adde

El Pliensbachiense de la Rama Aragonesa de la Cordillera Ibérica: Análisis de facies y establecimiento de secuencias

The Pliensbachian of the Aragonese branch of the Iberian Chain is represented by Almonacid de la Cuba, Cerro del Pez and Barahona formations. These sediments are constituted by marls and limestone organized in shallowingupward sequences. All of them are represented in the lower part by marls and mudstone that change to wackestone and packstone. The top of the sequence is a ferruginous crust, generally bioturbated. This represents the decrease in the sedimentation velocity and a shallowing event. The sediments were deposited in a carbonate ramp, changing from middle to outer environments. The most shallowing facies were located in the south, where there is an evidence of the developing of reefal facies. The deeper facies were deposited in the north, corresponding to open environments. This work shows the correlation of six thirdorder shallowing upward sequences in the Pliensbachian sediments. The origin of these sequences is related to sea level oscillations and conditioned by autocyclic processes

A mud-dominated coastal plain to lagoon with emerged carbonate mudbanks: The imprint of low-amplitude sea level cycles (mid-Upper Cretaceous, South Iberian Ramp)

The middle Santonian-lower Campanian carbonate-mud dominated succession deposited in the northeastern margin of the South Iberian Ramp (La Cañadilla Fm, NE Spain) shows a complex set of interfingered facies developed in a low-energy and low-gradient shallow-marine to coastal environment. Three facies belts characterize the environment reconstructed in this work: (1) a low-energy shallow marine lagoon dominated by radiolitid rudist limestones and miliolid-rich facies with variable carbonate-mud content; (2) a transitional belt with a patchy distribution of ponds and mudbanks. This belt mostly consists of miliolid-rich limestones with variable amount of fenestral porosity, which are interfingered with charophytes and gastropod marls and limestones usually mixed with miliolids; (3) a coastal plain with strong freshwater influence characterized by the sedimentation of marls and limestones with charophytes, gastropods and root traces and intraclastic/black pebble limestones. The studied succession is arranged in high-frequency sequences, including meter-scale parasequences bounded by widespread flooding surfaces, which stack in five larger-scale shallowing-upward sequences (6–20 m thick). The time calibration of these sequences obtained from strontium isotopes and biostratigraphic data (benthic foraminifera) suggests a major control in the sedimentation by climate-driven low-amplitude sea level oscillations formed in tune with the long- and short-eccentricity orbital cycles. Cyclic sea level rises controlled the existence of widespread flooding events in the low-gradient carbonate ramp at the onset of parasequences, which in the studied marginal areas of the South Iberian Ramp were mostly sourced from the southern Tethyan realm. Therefore, the La Cañadilla Fm provides an example of a complex shallow marine to coastal system giving rise to a mosaic distribution of carbonate-mud dominated facies, with sedimentation mostly influenced by external factors resulting in a well-defined stratigraphic architecture. The similarities with modern analogous systems such as the Ten Thousand Islands of the Florida Bay are discussed in this paper. © 2022 Elsevier B.V