Marin, Brigitte y Virlouvet, Catherine (eds.), "Entrepôts et trafics annonaires en Méditerranée: antiquité-temps modernes", Roma, École française de Rome, 2016, 406 págs., ISBN: 978-2-7283-1246-7

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Genoese galley contractors and shipping connections in a polycentric empire (sixteenth and seventeenth centuries)

Este artículo analiza la función que la escuadra de los asentistas de galeras genoveses desempeñó en la articulación de varios componentes territoria­les del imperio hispánico entre la segunda mitad del siglo XVI y la primera mitad del siglo XVII. Mientras los estudios sobre la flota mediterránea de la Monarquía se han focalizado generalmente en el ejercicio de la guerra naval, este artículo muestra que, más allá de esta actividad, la escuadra de los genoveses fue clave para el transporte de soldados, metales preciosos, élites de gobierno e información entre la Península Ibérica y el norte de Ita­lia. Este papel fue particularmente relevante durante la guerra de los Ochenta Años (1568-1648), cuando la situación en el Atlántico obligó a la Corona a utilizar el Mediterráneo como plataforma logística para la movi­lización de recursos hacia el norte de Europa. A través del análisis de la aportación de la escuadra hispano-genovesa a esta tarea de articulación naval, este trabajo pretende contribuir a un mayor entendimiento de las ins­tituciones de tipo transnacional que fomentaban la conexión y la circula­ción entre los diferentes componentes de un imperio policéntrico

Individual-based modelling of tropical forests: role of biodiversity and responses to drought

La faible représentation de la biodiversité dans les modèles de végétation a longtemps été un obstacle à la compréhension et à la projection des processus écosystémiques. La forte biodiversité des forêts tropicales, leur rôle clé dans les cycles biogéochimiques globaux, ainsi que leur vulnérabilité aux perturbations anthropiques directes et indirectes, amplifient les difficultés et enjeux de ces questions de recherche. En particulier, l'augmentation prédite de la fréquence et de l'intensité des sécheresses pourrait impacter la structure et composition floristique de ces forêts, comme dors et déjà observé au cours d'expériences naturelles et artificielles. Cette thèse explore ces questions de recherche à travers deux approches complémentaires, de modélisation et de mesures écophysiologiques. Dans le premier chapitre, je décris un simulateur de croissance forestière individu-centré et spatialement-explicite, TROLL, qui intègre les progrès récents en physiologie des plantes. Les processus sont paramétrés à l'aide de traits fonctionnels espèce-spécifiques, pour une forêt tropicale amazonienne. Une régénération forestière est simulée, et validée par des observations faites en Guyane française. La sensibilité du modèle à plusieurs paramètres globaux clés est évaluée. Enfin, l'influence de la variation de la richesse et composition spécifiques sur les propriétés écosystémiques est explorée. La réponse des forêts tropicales à la sécheresse est mal connue, empêchant la représentation pertinente des processus en jeu dans les modèles de végétation. Les chapitres 2 à 5 de cette thèse ont ainsi pour but de documenter la tolérance à la sécheresse et sa diversité dans une forêt amazonienne. Une méthode récente et rapide de détermination d'un trait de tolérance des feuilles à la sécheresse, le potentiel hydrique des feuilles au point de perte de turgescence (ptlp), est validée et utilisée, permettant de quantifier pour la première fois un tel trait de tolérance à la sécheresse dans une forêt amazonienne à l'échelle de la communauté. Ce jeu de données permet l'exploration des déterminants de la tolérance à la sécheresse des feuilles, à travers les espèces d'arbres, les tailles des individus, les stades de succession, les expositions à la lumière, ainsi que les lianes. La variabilité de ptlp observée suggère une large diversité de réponses à la sécheresse au sein des communautés de plantes amazoniennes. Ceci est confirmé par le suivi direct du flux de sève au cours d'une saison sèche sur divers arbres de canopée. Enfin, je discute les implications de ces résultats pour le développement des futurs modèles de végétation.A great part of uncertainties in our current understanding and projections of the carbon cycle lies in the vegetation compartment. The problem of biodiversity representation in vegetation models has long been an impediment to a detailed understanding of ecosystem processes. The high biodiversity of tropical forests, their disproportionate role in global biogeochemical cycles, together with their vulnerability to direct and indirect anthropogenic perturbations, amplify the relevance of this research challenge. In particular, the predicted increase in drought intensity and frequency in the tropics may impact forest structure and composition, as already observed in natural and artificial experiments. This thesis explores how new advances in modelling and ecophysiology should help improve our understanding of these processes in the future. In the first chapter, I describe an individual-based and spatially-explicit forest growth simulator, TROLL, that integrates recent advances in plant physiology. Processes are linked to species-specific functional traits parameterized for an Amazonian tropical rainforest. This model is used to simulate a forest regeneration, which is validated against observations in French Guiana. Model sensitivity is assessed for a number of key global parameters. Finally, we test the influence of varying the species richness and composition on ecosystem properties. Tropical forest response to drought is not well understood, and this hampers attempts to model these processes. In chapters 2 to 5 I aimed at documenting drought-tolerance and its diversity in an Amazonian forest. A rapid method of determination of a leaf drought tolerance trait, the leaf water potential at turgor loss point (ptlp), was validated and applied to a range of plant species. We established the first community-wide assessment of drought tolerance in an Amazonian forest. These results inform on the drivers and determinants of leaf drought tolerance, across tree species and lianas, tree size, successional stages, light exposition, and seasons. Variability in ptlp among species indicates the potential for a range of species responses to drought within Amazonian forest communities. This is further confirmed by direct monitoring of whole-plant water use on diverse canopy trees during a marked dry season. Finally, I discuss the implications of these results to increase the dialogue between the vegetation modeling community and ecology, to enhance model's predictive ability, and to inform policy choices

Prospective comparison of speckle tracking longitudinal bidimensional strain between two vendors

SummaryBackgroundSpeckle tracking is a relatively new, largely angle-independent technique used for the evaluation of myocardial longitudinal strain (LS). However, significant differences have been reported between LS values obtained by speckle tracking with the first generation of software products.AimsTo compare LS values obtained with the most recently released equipment from two manufacturers.MethodsSystematic scanning with head-to-head acquisition with no modification of the patient's position was performed in 64 patients with equipment from two different manufacturers, with subsequent off-line post-processing for speckle tracking LS assessment (Philips QLAB 9.0 and General Electric [GE] EchoPAC BT12). The interobserver variability of each software product was tested on a randomly selected set of 20 echocardiograms from the study population.ResultsGE and Philips interobserver coefficients of variation (CVs) for global LS (GLS) were 6.63% and 5.87%, respectively, indicating good reproducibility. Reproducibility was very variable for regional and segmental LS values, with CVs ranging from 7.58% to 49.21% with both software products. The concordance correlation coefficient (CCC) between GLS values was high at 0.95, indicating substantial agreement between the two methods. While good agreement was observed between midwall and apical regional strains with the two software products, basal regional strains were poorly correlated. The agreement between the two software products at a segmental level was very variable; the highest correlation was obtained for the apical cap (CCC 0.90) and the poorest for basal segments (CCC range 0.31–0.56).ConclusionsA high level of agreement and reproducibility for global but not for basal regional or segmental LS was found with two vendor-dependent software products. This finding may help to reinforce clinical acceptance of GLS in everyday clinical practice

Increased risk of left heart valve regurgitation associated with benfluorex use in patients with diabetes mellitus: a multicenter study.

International audienceBACKGROUND: Benfluorex was withdrawn from European markets in June 2010 after reports of an association with heart valve lesions. The link between benfluorex and valve regurgitations was based on small observational studies and retrospective estimations. We therefore designed an echocardiography-based multicenter study to compare the frequency of left heart valve regurgitations in diabetic patients exposed to benfluorex for at least 3 months and in diabetic control subjects never exposed to the drug. METHODS AND RESULTS: This reader-blinded, controlled study conducted in 10 centers in France between February 2010 and September 2011 prospectively included 376 diabetic subjects previously exposed to benfluorex who were referred by primary care physicians for echocardiography and 376 diabetic control subjects. Through the use of propensity scores, 293 patients and 293 control subjects were matched for age, sex, body mass index, smoking, dyslipidemia, hypertension, and coronary artery disease. The main outcome measure was the frequency of mild or greater left heart valve regurgitations. In the matched sample, the frequency and relative risk (odds ratio) of mild or greater left heart valve regurgitations were significantly increased in benfluorex patients compared with control subjects: 31.0% versus 12.9% (odds ratio, 3.55; 95% confidence interval, 2.03-6.21) for aortic and/or mitral regurgitation, 19.8% versus 4.7% (odds ratio, 5.29; 95% confidence interval, 2.46-11.4) for aortic regurgitation, and 19.4% versus 9.6% (odds ratio, 2.38; 95% confidence interval, 1.27-4.45) for mitral regurgitation. CONCLUSIONS: Our results indicate that the use of benfluorex is associated with a significant increase in the frequency of left heart valve regurgitations in diabetic patients. The natural history of benfluorex-induced valve abnormalities needs further research

Identifying uncertainties in scenarios and models of socio-ecological systems in support of decision-making

There are many sources of uncertainty in scenarios and models of socio-ecological systems, and understanding these uncertainties is critical in supporting informed decision-making about the management of natural resources. Here, we review uncertainty across the steps needed to create socio-ecological scenarios, from narrative storylines to the representation of human and biological processes in models and the estimation of scenario and model parameters. We find that socio-ecological scenarios and models would benefit from moving away from “stylized” approaches that do not consider a wide range of direct drivers and their dependency on indirect drivers. Indeed, a greater focus on the social phenomena is fundamental in understanding the functioning of nature on a human-dominated planet. There is no panacea for dealing with uncertainty, but several approaches to evaluating uncertainty are still not routinely applied in scenario modeling, and this is becoming increasingly unacceptable. However, it is important to avoid uncertainties becoming an excuse for inaction in decision-making when facing environmental challenges.</p

The function-dominance correlation drives the direction and strength of biodiversity-ecosystem functioning relationships

Community composition is a primary determinant of how biodiversity change influences ecosystem functioning and, therefore, the relationship between biodiversity and ecosystem functioning (BEF). We examine the consequences of community composition across six structurally realistic plant community models. We find that a positive correlation between species' functioning in monoculture versus their dominance in mixture with regard to a specific function (the "function-dominance correlation") generates a positive relationship between realised diversity and ecosystem functioning across species richness treatments. However, because realised diversity declines when few species dominate, a positive function-dominance correlation generates a negative relationship between realised diversity and ecosystem functioning within species richness treatments. Removing seed inflow strengthens the link between the function-dominance correlation and BEF relationships across species richness treatments but weakens it within them. These results suggest that changes in species' identities in a local species pool may more strongly affect ecosystem functioning than changes in species richness

Conservation prioritization can resolve the flagship species conundrum

Conservation strategies based on charismatic flagship species, such as tigers, lions, and elephants, successfully attract funding from individuals and corporate donors. However, critics of this species-focused approach argue it wastes resources and often does not benefit broader biodiversity. If true, then the best way of raising conservation funds excludes the best way of spending it. Here we show that this conundrum can be resolved, and that the flagship species approach does not impede cost-effective conservation. Through a tailored prioritization approach, we identify places containing flagship species while also maximizing global biodiversity representation (based on 19,616 terrestrial and freshwater species). We then compare these results to scenarios that only maximized biodiversity representation, and demonstrate that our flagship-based approach achieves 79−89% of our objective. This provides strong evidence that prudently selected flagships can both raise funds for conservation and help target where these resources are best spent to conserve biodiversity