Petrogenesis of Mafic to Felsic Lavas from the Oligocene Siebengebirge Volcanic Field (Germany): Implications for the Origin of Intracontinental Volcanism in Central Europe

Magmatism in the Cenozoic Central European Volcanic Province (CEVP) has been related to two geodynamic scenarios, either extensional tectonics in the north Alpine realm or upwelling of deep mantle material. The Oligocene (∼30-19 Ma) Siebengebirge Volcanic Field (SVF) is a major part of the German portion of the CEVP and consists of erosional remnants of mafic to felsic volcanic edifices. It covers an area of ∼35 km (NW-SE) by ∼25 km (SW-NE) with eruptive centres concentrated near the eastern shore of the Rhine river in the vicinity of the city of Bonn. Mafic rocks in the SVF comprise strongly SiO2-undersaturated basanites to alkaline basalts. Occurrences of alkaline basalts are confined to an inner NW-SE-striking zone, whereas the more SiO2-undersaturated basanites dominate the western and eastern periphery of the SVF. Radiogenic isotope compositions (87Sr/86Sr 0·70335-0·70371; εNd +3·1 to +4·5; εHf +6·5 to +8·0; 206Pb/204Pb 19·46-19·69; 207Pb/204Pb 15·63-15·66; 208Pb/204Pb 39·34-39·62) indicate a common asthenospheric mantle end-member with HIMU-like characteristics for all mafic rocks, similar to the European Asthenospheric Reservoir (EAR). A lithospheric mantle source component with a residual K-bearing phase (phlogopite or amphibole) is inferred from negative K anomalies. Incompatible trace element modelling indicates that melting took place in the spinel-garnet transition zone with low degrees of melting at higher pressures generating the basanitic magmas (LaN/YbN = 20-25), whereas the alkaline basalts (LaN/YbN = 14-18) are the result of higher melting degrees at shallower average melting depths. Differentiation of basanitic primary melts generated tephritic to tephriphonolitic magmas that, for instance, erupted at the Löwenburg Volcanic Complex in the central SVF. Latites and trachytes, such as the prominent Drachenfels and Wolkenburg protrusions, are more common in the central portion of the SVF. These compositions originate from parental alkaline basaltic melts. All differentiated samples show evidence for crustal contamination, possibly with lower- to mid-crustal material comprising mafic granulites as found in Eifel basalt xenoliths and metapelites. Based on the spatial and temporal distribution of the various volcanic rock types, a model for the temporal evolution of the SVF can be proposed. During the initial phase of volcanism, low-degree basanitic melts were generated as a result of decompression following tectonic rifting and formation of the Cologne Embayment, a northward extension of the Rhine Graben. In a second stage, alkali basalts were generated at shallower depths and higher degrees of melting as a result of continued lithospheric thinning and passive upwelling of asthenospheric mantle. These conclusions strengthen previous models suggesting that intraplate volcanism in Central Europe is directly linked to regional lithospheric thinning and asthenospheric upwelling. Overall, the SVF constitutes an exceptionally well-preserved magmatic assemblage to illustrate these tectono-magmatic relationship

Éclairer le choix des outils de simulation des changements des modes d'occupation et d'usages des sols. Une approche comparative.

International audienceDurant les dernières décennies, une variété de modèles ont été développés pour simuler les changements futurs des modes d'occupation et d'usage des sols. Dans cette étude, nous avons comparé quatre logiciels de modélisation : CLUE-S, DINAMICA EGO, CA_Markov et Land Change Modeler. Nous avons examiné les différentes méthodes et outils disponibles dans chaque modèle pour reproduire les étapes nécessaires pour une telle approche de modélisation : 1) estimation de la quantité de changement, 2) caractérisation des changements observés par des variables explicatives, 3) allocation spatiale des changements, 4) reproduction des patrons spatiaux, 5) évaluation de la performance du modèle et 6) capacité pour développer des modèles sophistiqués. Pour illustrer cette analyse, les modèles ont été appliqués à des études de cas théoriques très simples. Nous avons comparé les différents résultats issus de cette démarche de modélisation (projection des surfaces de changements futurs, cartes de probabilité de changement, cartes des modes d'occupation et d'usage des sols futurs) afin d'objectiver nos conclusions portant sur la flexibilité et la capacité des modèles pour effectuer les différentes tâches listées. Le but de cette étude vise à éclairer les futurs utilisateurs à faire un choix de modèle approprié suivant leur problématique

Una comparación de diferentes enfoques de modelación de cambios de cobertura/uso del suelo

International audienceDurante las últimas décadas, una gran variedad de modelos fueron desarrollados para predecir la localización de los CUCS. En este estudio, se comparan cuatro programas de modelación: CLUE, DINAMICA EGO, CA_Markov and Land Change Modeler (ambos disponible en IDRISI). En un primer paso, se revisaron los diferentes métodos y herramientas disponibles en cada modelo para llevar a cabo los diferentes pasos de la modelación (estimación de la cantidad de cambio, relación entre las variables explicativas y los cambios, alocación de los cambios, reproducción de los patrones espaciales, evaluación del desempeño del modelo, posibilidad de desarrollar modelos más sofisticados). En un paso siguiente, se aplicaron los modelos a un caso de estudio virtual, basado en un escenario de deforestación sencillo. Esta estrategia nos permitió comparar los modelos en situaciones controladas y desarrollar situaciones retadoras para evaluar el desempeño de cada modelo. Se compararon los diferentes productos de la modelación (mapas de probabilidad de cambio, mapas de coberturas simulados) y se evaluaron los modelos tomando en cuanto su flexibilidad y capacidad para llevar a cabo las diferentes tareas relacionadas con la modelación

Inductive pattern-based land use/cover change models: A comparison of four software packages

International audienceLand use/cover change (LUCC), as an important factor in global change, is a topic that has recently received considerable attention in the prospective modeling domain. There are many approaches and software packages for modeling LUCC, many of them are empirical approaches based on past LUCC such as CLUES , DINAMICA EGO, CA_MARKOV and Land Change Modeler (both available in IDRISI). This study reviews the possibilities and the limits of these four modeling software packages. First, a revision of the methods and tools available for each model was performed, taking into account how the models carry out the different procedures involved in the modeling process: quantity of change estimate, change potential evaluation, spatial allocation of change, reproduction of temporal and spatial patterns, model evaluation and advanced modeling options. Additional considerations, such as flexibility and user friendliness were also taken into account. Then, the four models were applied to a virtual case study to illustrate the previous descriptions with a typical LUCC scenario that consists of four processes of change (conversion of forest to two different types of crops, crop abandonment and urban sprawl) that follow different spatial patterns and are conditioned by different drivers. The outputs were compared to assess the quantity of change estimates, the change potential and the simulated prospective maps. Finally, we discussed some basic criteria to define a " good " model

Dendritic Plasticity in the Adult Rat Following Middle Cerebral Artery Occlusion and Nogo-A Neutralization

Our work has shown that following focal ischemic lesion in adult rats, neutralization of the axon growth inhibitor Nogo-A with the monoclonal antibody (mAb) IN-1 results in functional recovery. Furthermore, new axonal connections were formed from the contralesional cortex to subcortical areas corresponding to the observed functional recovery. The present study investigated whether dendritic changes, also known to subserve functional recovery, paralleled the axonal plasticity shown after ischemic lesion and treatment with mAb IN-1. Golgi-Cox-stained layer V pyramidal neurons in the contralesional sensorimotor cortex were examined for evidence of dendritic sprouting. Results demonstrated increased dendritic arborization and spine density in the mAb IN-1-treated animals with lesion. Interestingly, administration of mAb IN-1 without lesion resulted in transient dendritic outgrowth with no change in spine density. These results suggest a novel role for Nogo-A in limiting dendritic plasticity after strok

Post-2020 biodiversity targets need to embrace climate change

Recent assessment reports by the Intergovernmental Panel on Climate Change (IPCC) and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) have highlighted the risks to humanity arising from the unsustainable use of natural resources. Thus far, land, freshwater, and ocean exploitation have been the chief causes of biodiversity loss. Climate change is projected to be a rapidly increasing additional driver for biodiversity loss. Since climate change and biodiversity loss impact human societies everywhere, bold solutions are required that integrate environmental and societal objectives. As yet, most existing international biodiversity targets have overlooked climate change impacts. At the same time, climate change mitigation measures themselves may harm biodiversity directly. The Convention on Biological Diversity\u27s post-2020 framework offers the important opportunity to address the interactions between climate change and biodiversity and revise biodiversity targets accordingly by better aligning these with the United Nations Framework Convention on Climate Change Paris Agreement and the Sustainable Development Goals. We identify the considerable number of existing and proposed post- 2020 biodiversity targets that risk being severely compromised due to climate change, even if other barriers to their achievement were removed. Our analysis suggests that the next set of biodiversity targets explicitly addresses climate change-related risks since many aspirational goals will not be feasible under even lower-end projections of future warming. Adopting more flexible and dynamic approaches to conservation, rather than static goals, would allow us to respond flexibly to changes in habitats, genetic resources, species composition, and ecosystem functioning and leverage biodiversity\u27s capacity to contribute to climate change mitigation and adaptation

Una comparación de programas de modelación de cambios de cobertura/ uso del suelo

En las últimas décadas, una gran cantidad de modelos de cambios de cobertura / uso del suelo (CCUS) enfocados a la simulación de procesos de cambio han sido desarrollados. Los CCUS pueden modelarse empíricamente mediante un análisis de los cambios pasados para desarrollar un modelo matemático que estima la probabilidad de cambio en función de un conjunto de variables explicativas. En general, el análisis espacial de los cambios se lleva a cabo a través de la comparación de dos mapas de cobertura/uso del suelo (CUS) de dos fechas anteriores. Esta comparación permite estimar los patrones y procesos de cambio (tipos de transiciones y tasas de cambio). El análisis de los cambios pasados en relación con lasLand use/cover changes (LUCC) are significant to a range of issues central to the study of global environmental change and have thus have received growing attention by decision makers and scientists. Over the last decades, a range of models of LUCC have been developed to meet land management needs, and to better understand, assess and project the future role of LUCC in the functioning of the earth system. This study intends to compare the possibilities and the limits of four modelling approaches: CLUE, DINAMICA EGO, CA_MARKOV and Land Change Modeler (both available in IDRISI). First, a review of methods and tools available for each model was done taking into account how the model carry out the different procedures involved in the modelling process (Estimation of the quantity of changes, finding of the relationship between the explanatory variables and the changes in order to assess the degree of change potential, change allocation, simulation of spatial patterns of changes, model evaluation). The four models were applied to simple case studies and model outputs were compared. variables explicativas permite mapear la probabilidad de las diferentes transiciones. Otros procedimientos, aplicados con el fin de crear un mapa prospectivo de CUS, involucran técnicas para asignar los cambios en el espacio y, finalmente, para reproducir los patrones espaciales de los paisajes. Por último, se lleva usualmente a cabo una evaluación del desempeño del modelo.Este estudio se llevó a cabo en el ámbito del proyecto Simulaciones geomáticas para modelizar dinámicas ambientales. Avances metodológicos y temáticos (BIA2008-00681)

Impaired Bile Acid Metabolism and Gut Dysbiosis in Mice Lacking Lysosomal Acid Lipase

Lysosomal acid lipase (LAL) is the sole enzyme known to be responsible for the hydrolysis of cholesteryl esters and triglycerides at an acidic pH in lysosomes, resulting in the release of unesterified cholesterol and free fatty acids. However, the role of LAL in diet-induced adaptations is largely unexplored. In this study, we demonstrate that feeding a Western-type diet to Lal-deficient (LAL-KO) mice triggers metabolic reprogramming that modulates gut-liver cholesterol homeostasis. Induction of ileal fibroblast growth factor 15 (three-fold), absence of hepatic cholesterol 7α-hydroxylase expression, and activation of the ERK phosphorylation cascade results in altered bile acid composition, substantial changes in the gut microbiome, reduced nutrient absorption by 40%, and two-fold increased fecal lipid excretion in LAL-KO mice. These metabolic adaptations lead to impaired bile acid synthesis, lipoprotein uptake, and cholesterol absorption and ultimately to the resistance of LAL-KO mice to diet-induced obesity. Our results indicate that LAL-derived lipolytic products might be important metabolic effectors in the maintenance of whole-body lipid homeostasis

How will climate change pathways and mitigation options alter incidence of vector-borne diseases? A framework for leishmaniasis in South and Meso-America

The enormous global burden of vector-borne diseases disproportionately affects poor people in tropical, developing countries. Changes in vector-borne disease impacts are often linked to human modification of ecosystems as well as climate change. For tropical ecosystems, the health impacts of future environmental and developmental policy depend on how vector-borne disease risks trade off against other ecosystem services across heterogeneous landscapes. By linking future socio-economic and climate change pathways to dynamic land use models, this study is amongst the first to analyse and project impacts of both land use and climate change on continental-scale patterns in vector-borne diseases. Models were developed for cutaneous and visceral leishmaniasis in the Americas—ecologically complex sand fly borne infections linked to tropical forests and diverse wild and domestic mammal hosts. Both diseases were hypothesised to increase with available interface habitat between forest and agricultural or domestic habitats and with mammal biodiversity. However, landscape edge metrics were not important as predictors of leishmaniasis. Models including mammal richness were similar in accuracy and predicted disease extent to models containing only climate and land use predictors. Overall, climatic factors explained 80% and land use factors only 20% of the variance in past disease patterns. Both diseases, but especially cutaneous leishmaniasis, were associated with low seasonality in temperature and precipitation. Since such seasonality increases under future climate change, particularly under strong climate forcing, both diseases were predicted to contract in geographical extent to 2050, with cutaneous leishmaniasis contracting by between 35% and 50%. Whilst visceral leishmaniasis contracted slightly more under strong than weak management for carbon, biodiversity and ecosystem services, future cutaneous leishmaniasis extent was relatively insensitive to future alternative socio-economic pathways. Models parameterised at narrower geographical scales may be more sensitive to land use pattern and project more substantial changes in disease extent under future alternative socio-economic pathways