Uniqueness Results for Second Order Bellman-Isaacs Equations under Quadratic Growth Assumptions and Applications

In this paper, we prove a comparison result between semicontinuous viscosity sub and supersolutions growing at most quadratically of second-order degenerate parabolic Hamilton-Jacobi-Bellman and Isaacs equations. As an application, we characterize the value function of a finite horizon stochastic control problem with unbounded controls as the unique viscosity solution of the corresponding dynamic programming equation

Robust Circle Detection

International audienceIn this paper we present a method of robustly detect circles in a line drawing image. The method is fast, robust and very reliable, and is capable of assessing the quality of its detection. It is based on Random Sample Consensus minimization, and uses techniques that are inspired from object tracking in image sequences

Investigating the vertical extent and short-wave radiative effects of the ice phase in Arctic summertime low-level clouds

Low-level (cloud tops below 2 km) mixed-phase clouds are important in amplifying warming in the Arctic region through positive feedback in cloud fraction, water content and phase. In order to understand the cloud feedbacks in the Arctic region, good knowledge of the vertical distribution of the cloud water content, particle size and phase is required. Here we investigate the vertical extent of the cloud-phase and ice-phase optical properties in six case studies measured in the European Arctic during the ACLOUD campaign. Late spring- and summertime stratiform clouds were sampled in situ over pack ice, marginal sea ice zone and open-ocean surface, with cloud top temperatures varying between −15 and −1.5 ∘C. The results show that, although the liquid phase dominates the upper parts of the clouds, the ice phase was frequently observed in the lower parts down to cloud top temperatures as warm as −3.8 ∘C. In the studied vertical cloud profiles, the maximum of average liquid phase microphysical properties, droplet number concentration, effective radius and liquid water content, varied between 23 and 152 cm−3, 19 and 26 µm, 0.09 and 0.63 g m−3, respectively. The maximum of average ice-phase microphysical properties varied between 0.1 and 57 L−1 for the ice number concentration, 40 and 70 µm for the effective radius, and 0.005 and 0.08 g m−3 for the ice water content. The elevated ice crystal number concentrations and ice water paths observed for clouds, with cloud top temperatures between −3.8 and −8.7 ∘C can be likely attributed to secondary ice production through rime splintering. Low asymmetry parameters between 0.69 and 0.76 were measured for the mixed-phase ice crystals with a mean value of 0.72. The effect of the ice-phase optical properties on the radiative transfer calculations was investigated for the four cloud cases potentially affected by secondary ice production. Generally the choice of ice-phase optical properties only has a minor effect on the cloud transmissivity and albedo, except in a case where the ice phase dominated the upper cloud layer extinction. In this case, cloud albedo at solar wavelengths was increased by 10 % when the ice phase was given its measured optical properties instead of treating it as liquid phase. The presented results highlight the importance of accurate vertical information on cloud phase for radiative transfer and provide a suitable data set for testing microphysical parameterizations in models

Arancou (Bourrouilla), Bilan scientifique 2005 du Service Régional de l'Archéologie Aquitaine

Bilan scientifique 2006 du Service Régional de l'Archéologie AquitaineBilan de la compagne de fouille à la grotte Bourrouilla à Arancou (64

L'horizontal et le vertical - L'âge du Bronze de la grotte des Fraux (Saint-Martin-de-Fressengeas - Dordogne)

articleDécouverte accidentellement en 1989, la grotte des Fraux (Dordogne) constitue un rare exemple de site de l'âge du Bronze qui regroupe en son sein des vestiges archéologiques et des manifestations pariétales. Les conditions exceptionnelles de la fossilisation du site à la fin de l'âge du Bronze, suite à l'effondrement de son principal accès, ont permis aux vestiges de nous parvenir dans un exceptionnel état de conservation. Sols de circulation, structures de combustion, structures architecturales, mobiliers mis en scène et œuvres pariétales forment un tout indissociable. L'étude interdisciplinaire qui s'engage se doit ainsi d'appréhender la cavité comme un système complexe, non plus réduit aux deux dimensions verticales et horizontales. Les combinaisons de l'Espace et du Temps requièrent de mettre en œuvre des méthodes susceptibles de retranscrire et d'interpréter l'écheveau des données archéologiques

From Berlin-Dahlem to the Fronts of World War I: The Role of Fritz Haber and His Kaiser Wilhelm Institute in German Chemical Warfare

There is little doubt that Fritz Haber (1868–1934) was the driving force behind the centrally directed development of chemical warfare in Germany, whose use during World War I violated international law and elicited both immediate and enduring moral criticism. The chlorine cloud attack at Ypres on 22 April 1915 amounted to the first use of a weapon of mass destruction and as such marks a turning point in world history. Following the “success” at Ypres, Haber, eager to employ science in resolving the greatest strategic challenge of the war—the stalemate of trench warfare—promptly transformed his Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry in Berlin-Dahlem into a center for the development of chemical weapons and of protective measures against them. This article traces in some detail the path from Berlin-Dahlem to the fronts of World War I, lays out the indispensible role of Fritz Haber in German chemical warfare and provides a summary of his views on chemical weapons, which he never renounced

Innovations for the sustainability transformation: Conceptual cornerstones of the saguf working group INSIST

How can we understand, analyze and design innovations for the sustainability transformation? The newly formed saguf working group INSIST explores the links between sustainability, innovation and transformation in theoretical, empirical and practical respects. The focus is to move away from a technicist framework of ecological modernization to a more reflexive and inclusive concept of transformative innovation

Estabilização proteica de vinhos: avaliação de alternativas para minimizar a aplicação de bentonite

As características sensoriais de um vinho, assim como a sua estabilidade, são fatores determinantes para a aceitabilidade do vinho no mercado, face à exigência dos consumidores atuais. A desnaturação das proteínas do vinho é responsável pelo aparecimento de turvação nos vinhos brancos. Esta instabilidade proteica pode ser causada por fatores intrínsecos ou extrínsecos, como peso molecular e ponto isoelétrico das frações proteicas no vinho, força iónica, grau alcoólico e pH do vinho ou condições de armazenamento. Para prevenir a instabilidade proteica são usados vários produtos enológicos com objetivo de remover as proteínas instáveis, evitando assim a sua desnaturação/precipitação. O agente de colagem mais usado para adsorção das proteínas do vinho é a bentonite sódica. Esta possui carga elétrica negativa, com capacidade de interagir eletroestaticamente com as proteínas do vinho de carga maioritariamente positiva, conduzindo à sua floculação e consequente precipitação. Apesar da colagem com bentonite ser o método mais utilizado, apresenta algumas limitações, particularmente quando aplicada em doses elevadas. Isto sucede, porque a bentonite para além de remover proteínas pode também interagir com outros compostos, nomeadamente com os que contribuem positivamente nas características sensoriais, tais como os compostos voláteis. Assim, um dos objetivos do presente trabalho foi avaliar a aplicação de aditivos enológicos que permitam estabilizar as proteínas do vinho branco, em alternativa à bentonite. Numa fase preliminar, foram testados diferentes produtos nomeadamente bentonite, taninos enológicos, carboximetilcelusose (CMC), enzimas, gel de sílica, quitosana e manoproteínas em diferentes doses, com o intuito de avaliar o seu efeito na estabilização proteica do vinho branco. A bentonite e as manoproteínas foram os que apresentaram melhores resultados de estabilidade proteica. Considerando os resultados obtidos, foram selecionadas cinco bentonites e onze manoproteínas comerciais, para ensaios de estabilização das proteínas dum vinho branco. Foi avaliada a influência destes produtos enológicos na composição fenólica, capacidade de acastanhamento, características cromáticas e sensoriais do vinho branco. Os resultados obtidos confirmaram a eficiência da bentonite na estabilização proteica dos vinhos. Por outro lado, algumas manoproteínas estudadas também mostraram uma influência positiva na estabilização proteica do vinho. Inserido no presente estudo foi ainda efetuada uma caracterização das manoproteínas quanto à sua composição em açúcares (quantitativo e qualitativo) e o conteúdo em proteína. Com base na caracterização efetuada às manoproteínas foi possível estabelecer uma ligação entre a percentagem de manose e a sua eficiência na estabilização proteica do vinho, dependendo esta da percentagem de manose. A bentonite não influenciou a composição fenólica, mas algumas manoproteínas diminuíram os compostos fenólicos totais. Relativamente às características cromáticas as manoproteínas de um modo geral conduziram a um aumento da luminosidade (L*) e a um aumento da coordenada da cromaticidade (b*), contudo apenas um dos vinhos tratados apresentou uma variação de cor detetável pelo olho humano. Na análise sensorial, não foram detetadas diferenças significativas nos vinhos analisados, porém, após a análise de componentes principais, foi possível descriminar os vinhos em três grupos, sendo o grupo mais pontuado aquele que continha apenas vinhos tratados com manoproteínas. Estes resultados estão de acordo com a caracterização dos açúcares efetuada às manoproteínas, sugerindo que a elevada pontuação atribuída a este grupo, se encontra relacionada com a elevada percentagem em glucose. Este trabalho pode fornecer informações importantes, conducentes a alternativas eficientes na estabilização proteica de vinhos brancos e que simultaneamente incrementa as características sensoriais do vinho. The sensory characteristics of a wine, as well the stability, are determinant factors for acceptability of wine in the market, face of current consumer exigency. White wine proteins denaturation is responsible for the appearance of haze in white wine. This protein instability may be caused by intrinsic or extrinsic factors, such as molecular weight and isoelectric point of wine protein fraction, ionic strength, pH and alcohol content of wine or storage conditions. To prevent protein instability, several oenological products are used, with the aimed to remove instable proteins, preventing their denaturation/precipitation. Sodium bentonite is the most commonly fining agent used to adsorption of wine proteins. This compound has a negative electrical charge, with capacity to interact electrostatically with wine proteins charged mostly positively, leading to flocculation and consequently precipitation. Although fining with bentonite being the most commonly used method, present some limitations, particularly when applied in high doses. This occurs, because addition of bentonite remove proteins and may interact with other compounds, namely with compounds that contribute positively in sensorial characteristics, such as volatile compounds. Thus, the propose of this work was to evaluate the application of oenological additives, that enable stabilize white wine proteins, as an alternative to bentonite. In a preliminary trial, were tested different types of products, namely bentonite, oenological tannins, carboxylmethylcellulose (CMC) enzymes, silica gel, chitosan and mannoproteins with different dosage, in order to evaluate their effect in white wine proteins stabilization. Bentonite and mannoproteins presented the best results. Based on these results we select five bentonites and eleven commercial mannoproteins. In this trials, it was evaluated the influence of this oenological products in phenolic composition, browning potential, chromatic and sensory characteristics of a white wine. The results obtained confirm the efficiency of bentonite in wine protein stabilization. Moreover, some mannoproteins studied also showed a positive influence in wine protein stabilization. Inserted into this study, it was also performed a mannoprotein characterization on sugars composition (quantitative and qualitative) and protein content. Based on mannoprotein characterization, it was possible to establish a relation between percentage of mannose and its efficiency in wine protein stabilization, depending on mannose percentage. Bentonite did not influence phenolic composition, but some mannoproteins decreased the total phenolic compounds. Regarding chromatic characteristics mannoproteins generally lead to an increase in lightness (L*) and an increase in yellowness (b*), however just one treated wine showed a variation in colour detected by human eye. In sensory analyses, no significant differences were detected among the analyzed wines, however, after principal components analyses; it was possible to discriminate wines into three groups, being the high scored group, which contains just wine treated with mannoproteins. This results are in accordance with sugars characterization performed at mannoproteins, which may suggest that high score attributed at this group is related with high percentage of glucose. This work may provide important information, leading to efficient alternatives in white wine proteins stabilization, and simultaneously, increase sensory characteristics

Macrophage Plasticity in Experimental Atherosclerosis

As in human disease, macrophages (MØ) are central players in the development and progression of experimental atherosclerosis. In this study we have evaluated the phenotype of MØ associated with progression of atherosclerosis in the apolipoprotein E (ApoE) knockout (KO) mouse model