China's new relations with Panama and Costa Rica are another step towards a Beijing Consensus in Central America

Increased trade, aid, investment, and diplomatic engagement between China and both Costa Rica and Panama signal a more general projection of Chinese economic and political standards in international trade policy, writes Sophie Wintgens. China's strategy towards Latin America and the Caribbean (LAC) fulfils four main interests: securing energy, mining, and agricultural resources abroad to maintain domestic economic growth getting political ..

A revised DR Congo mining code could lead to a decrease in Chinese investment in the country

As China shows indications of being willing to fall in line with international standards on procuring conflict minerals, Sophie Wintgens examines the strategic issues facing China as DR Congo seeks to revise its mining code

Influence of geometry on the emitting properties of 2,3-naphthalimides

The luminescence properties of 2,3-naphthalimides have been studied using picosecond and nanosecond spectroscopies. In acetonitrile solution N-phenyl-2,3-naphthalimid(e3 ) is found to emit dual fluorescence with emission maxima at 385 and 490 nm, respectively. The short-wavelength emission corresponds to the known fluorescence of the naphthalimides and is demonstrated for 3 to originate from a molecular conformation in which the phenyl substituent and the naphthalimide skeleton are orthogonal to each other. The long-wavelength emission is assumed to originate from a singlet excited state formed by a ca. 90° rotation of the phenyl group so that the two moieties are coplanar. Only a small dipole moment change is found between this excited state and the ground state. Only short-wavelength emission is observed with a lifetime in the nanosecond range as in the case of 1 and 2 when phenyl rotation is blocked with a bulky ortho tert-butyl group (compound 4). Increasing the viscosity of a glycerol/ethanol medium enhances both the efficiency and the lifetime of the short-wavelength emission of 3. It appears that at 77 K the emission originates directly from the Franck-Condon state. At room temperature, the other two emitting species are shown to arise from the Franck-Condon state by competitive intramolecular geometrical relaxation processes. Structures 5 and 6 are tentatively put forward to explain the formation of naphthazepinedione 8 by a 2 \pi + 2 \pi photochemical cycloaddition reaction

Effect of molecular structure and hydrogen bonding on the fluorescence of hydroxy-substituted naphthalimides

Fluorescence properties of hydroxy-naphthalimides were studied in methylene chloride in the absence and the presence of hydrogen-bonding additives. The position of the HO-substituent only slightly affects the radiative rate, however, the triplet yield and the rate of the radiationless processes are considerably higher for the 3-hydroxy derivative. Addition of nitrogen-heterocyclic compounds leads not only to hydrogen-bonding in the ground state but also Ñuorescence quenching. The parallel change throughout the series of the hydrogen-bond acceptors between the proton affinity and the rate constants of dynamic quenching indicates that proton displacement plays a crucial role in the excited hydrogen-bonded complexes. Interaction of hydroxy-naphthalimides with pyridine and benzoxazole results in rapid radiationless deactivation from the singlet excited state, whereas intense emission as well as long Ñuorescence lifetime characterize imidazole and pyrazole complexes. The dual emission of the imidazole complexes observed in solvents of medium polarity is assigned to two conformers which differ in the extent of the proton shift along the hydrogen-bond

Ion pair formation via photoinduced proton transfer in excited hydroxynaphthalimide-N-methylimidazole hydrogen bonded complex: effect of temperature and viscosity on dual fluorescence

The kinetics of photoinduced processes in the hydrogen bonded complex between N-methyl-3- hydroxynaphthalimide and 1-methylimidazole was studied in a wide temperature range in ethyl acetate and glycerol triacetate. The proton transfer within the excited complex was found to be very fast because of its negligible activation energy. The fairly intense dual Ñuorescence was assigned to hydrogen bonded and solvent separated ion pairs. Kinetic parameters for the various deactivation pathways of these excited species were derived from the combined analysis of the steady-state and the time-resolved Ñuorescence results. The Arrhenius pre-exponential factor of the transition from the solvent separated into the hydrogen bonded ion pair proved to be more than two orders of magnitude larger in glycerol triacetate compared with that in ethyl acetate, whereas the other processes showed less viscosity dependence. The radiationless energy dissipation rate of the hydrogen bonded ion pair was insensitive to the experimental conditions. However, thermal enhanced internal conversion was observed for the solvent separated ion pair

MINOTAURUS: microorganism and enzyme immobilization: novel techniques and approaches for upgraded remediation of underground-, wastewater and soil

The European project MINOTAURUS aims to deliver innovative bio-processes to eliminate emerging and classic organic pollutants. These bio-processes are all based on the concept of immobilization of biocatalysts (microorganisms and enzymes) and encompass bioaugmentation, enzyme technology, rhizoremediation with halophytes, and a bioelectrochemical remediation process. The immobilization-based technologies are applied to engineered ex situ and natural systems in situ for the bioremediation of groundwater, wastewater and soil. The selection and application of modern physico-chemical, biological and ecotoxicological monitoring tools combined with a rational understanding of engineering, enzymology and microbial physiology is a pertinent approach to open the black-box of the selected technologies. Reliable process-monitoring constitutes the basis for developing and refining biodegradation kinetics models, which in turn will improve the predictability of performances to be achieved with our technologies. A key strength of MINOTAURUS is the possibility of direct implementation of our technologies at five European reference sites that are confronted with pollutants (two technologies will be tested on-site starting from the first year). We will deliver not only a set of tools, techniques, and processes, which will enhance the ability of our communities to respond to the challenges of organic pollutants but also frameworks for structuring and making evidence-based decisions for the most sustainable and appropriate bioremediation measures. The MINOTAURUS consortium includes fifteen partners from eight European countries. Eight research & education institutions, five SMEs covering the whole chain of our bioremediation approaches (production, and monitoring of biocatalysts, bioremediation and engineering), one large end-user operating wastewater treatment plants and one environmental agency work together with the support of an advisory board mainly consisting of environmental decision-maker

Polémique, Identité, Frontières. Le cas Django Unchained

Cet article s’intéresse à la manière dont une polémique peut devenir le lieu d’une affirmation identitaire pour une minorité, le lieu d’une lutte hégémonique pour le sens, le lieu où peuvent circuler des discours alternatifs participant à construire des identités, en se concentrant sur le cas de la polémique ayant émergé autour du film Django Unchained de Quentin Tarantino (2012). L’article s’articule autour d’une analyse des arguments ayant été produits par les détracteurs du film pour le qualifier de raciste (envers les Afro-Américains ou envers les Blancs) qui souligne le rôle de la représentation de l’identité afro-américaine dans la polémique. Il semble que cette polémique permette à une communauté minoritaire de contester une représentation d’elle-même et par là même de produire des discours participant à redéfinir son identité, à construire de nouvelles frontières identitaires, et dès lors à (re)définir la communauté.This paper explores the potential that controversies have to become places of identity assertion for minorities, places of hegemonic conflicts about the meaning, places where alternative discourses that participate in the building of an identity can circulate. It focuses on the controversy surrounding the movie Django Unchained by Quentin Tarantino (2012) and hinges on an analysis of arguments having been produced by some movie’s detractors to call it racist (towards African Americain or towards White people). This analysis underlines the part played by the representation of the African American identity in the controversy. It seems that this controversy allows a community to contest a representation of itself and thereby to produce discourses which will redefine its identity, to build new identity borders and, as a result, to (re)define the community