4,593 research outputs found
Strong and Confined Acids Enable a Catalytic Asymmetric Nazarov Cyclization of Simple Divinyl Ketones
We report a catalytic asymmetric Nazarov cyclization of simple, acylic, alkyl-substituted divinyl ketones using our recently disclosed strong and confined imidodiphosphorimidate Brønsted acids. The corresponding monocyclic cyclopentenones are formed in good yields and excellent regio-, diastereo-, and enantioselectivities. Further, the chemical utility of the obtained enantiopure cyclopentenones is demonstrated
Contentious Territorial Alliances: Coalition Politics and Struggles over Urban Development in Pikine, Senegal
Les litiges territoriaux qui concernent la gestion et l’aménagement des espaces urbains occupent un rôle central dans la recherche sur la gouvernance urbaine dans les pays du Sud. A partir du travail de terrain réalisé par l’auteur à Pikine, une ville qui s’est rapidement urbanisée dans la région de Dakar (Sénégal), cet article montre comment la géographie politique de Dakar se transforme par les reconfigurations spatiales engendrées par des stratégies territoriales multiples et superposées visant au développement d'une agriculture urbaine là où des poches d'espaces verts sont préservées. L’analyse de 2 cas de conflits –différents mais interconnectés- à propos de l’aménagement de terres agricoles urbaines en vue de lotissements pour la classe moyenne et les élites permet à l’auteur d’affirmer que des acteurs publics et privés - notamment des producteurs, des autorités traditionnelles, des promoteurs immobiliers, et des officiels dans les gouvernements locaux/centraux- abandonnent les anciennes formes de gouvernance au profit « d’alliances territoriales » afin de promouvoir leurs propres projets de développement urbain. Ces alliances territoriales conduisent à de nouvelles relations entre les membres des gouvernements locaux/centraux et la société civile et ont une incidence sur le cadastre, les droits de propriété et les infrastructures publique du Sénégal urbain.Contentious territorial struggles over how to manage and develop city spaces figure centrally in research on urban governance in the global South. Drawing from ethnographic fieldwork in Pikine, a rapidly urbanizing city in Senegal’s Dakar Region, this article examines how Dakar's political geography is being transformed by the configuration of multiple, overlapping territorial strategies for the development of urban farmland in one of the region’s few remaining pockets of green spaces. Through analysis of two spatially distinct –albeit interlinked– episodes of conflict over the development of middle-class and elite housing projects on Pikine farmland, I argue that various public and private actors –including farmers, traditional authorities, housing developers, and local/central government officials– are breaking with older forms of urban governance and forming what I call “territorial alliances” to stake land claims and advance urban development projects. These territorial alliances are producing new political relations between local/central government actors and associational life while also dramatically transforming the cadastre, property rights, and landscapes of public infrastructure in urban Senegal
Azine Activation via Silylium Catalysis
Practical, efficient, and general methods for the diversification of N-heterocycles have been a recurrent goal in chemical synthesis due to the ubiquitous influence of these motifs within bioactive frameworks. Here, we describe a direct, catalytic, and selective functionalization of azines via silylium activation. Our catalyst design enables mild conditions and a remarkable functional group tolerance in a one-pot setup
Water resource problems of energy projects in the Colorado River Basin
The successful development of western coal and oil shale deposits
is dependent, to a significant degree, on the availability of adequate
water supplies. EQL is involved in a study of the aggregate effects
of various energy activities in the upper Colorado River Basin on
downstream water quantity and quality. These activities will tend
to reduce the available water in the river, and could increase its
salinity, which is already so high as to interfere with downstream
domestic and agricultural use
Solid state television camera system Patent
Solid state television camera system consisting of monolithic semiconductor mosaic sensor and molecular digital readout system
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