Macro-language planning for multilingual education : focus on programmes and provision

This overview identifies some common features of macro-level language planning and briefly summarises the changing approaches to the analysis of macro-planning in the field. It previews six cases of language-in-education planning in response to linguistic diversity presented by the contributors to this issue. The cases show how macro-planning can either fail to recognise diverse ethnolinguistic identities or work to acknowledge them. Three common themes in language planning for multilingual education can be identified from the contributions: (i) top-down definitions of what counts as mother tongue can have both intended and unintended outcomes; (ii) language-as-problem responses to linguistic diversity can work to reinforce social exclusion; and (iii) the acknowledgement of diversity and minority language rights needs to flow through from statements of intent to on-the-ground implementation if they are to become a reality

Sulfur-Directed Olefin Oxidations: Observation of Divergent Reaction Mechanisms in the Palladium-Mediated Acetoxylation of Unsaturated Thioacetals

The Pd-mediated oxidation of unsaturated thioacetals gives either allyl or vinyl esters, depending on the substrate structure. We report the characterization of a range of sulfur-stabilized palladium intermediates via a combined computational and experimental NMR approach, demonstrating that the oxidation proceeds via two divergent reaction mechanisms. We were also able to synthesize an unusual sigma-bound Pd complex, via acetoxypalladation of an unsaturated dithiane, which was characterized by X-ray crystallography

Alkylation of (π-Allyl)palladium systems. Mechanism and regiocontrol

Palladium-catalyzed alkylation of 3-methyl-2-butenyl acetate with anions of dialkyl malonates gives the same product pattern as the stoichiometric alkylations of (η3-3-methylbutenyl)palladium chloride and the corresponding cationic complex. Consequently a (π-allyl)palladium intermediate is probable in the catalytic reaction. According to NMR evidence the reactive intermediate is a η3-allyl complex rather than a η1-allyl complex. Acceptor ligands, even weak ones such as phosphines, have a strong electronic influence on the reaction and direct the attack toward the more substituted position. The formal charge of the complexes is important to the reactivity, but when phosphines are present as acceptor ligands, the formation of cationic intermediates may not be necessary. © 1984 American Chemical Society

Removal of per- And polyfluoroalkyl substances (PFAS) from water by ceric(iv) ammonium nitrate

Ceric(iv) ammonium nitrate (CAN) in aqueous medium acts as an excellent precipitating agent for perfluorooctanesulfonic acid (PFOS). The Ce(iv) center plays a crucial role. Interestingly, Ce(iii) chloride showed much less effectiveness under similar conditions. The efficacy of CAN was reduced upon changing the substrate to perfluorooctanoic acid (PFOA)

Electron and Energy Transfer in Supramolecular Complexes Designed for Artificial Photosynthesis. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 631. 50 pp. Uppsala. ISBN 91-554-5

In the society of today the need for alternative energy sources is increasing. The construction of artificial devices for the conversion of sunlight into electricity or fuel seems very attractive from an environmental point of view, since these devices are based on processes that does not necessarily generate any harmful biproducts. In the oxygen evolving photosynthetic process highly efficient energy and electron transfer reactions are responsible for the conversion of the sunlight into chemically stored energy and if the same principles can be used in an artificial device, the only electron supply required, is water. This thesis describes energy and electron transfer reactions in supramolecular complexes where the reactions are intended to mimic the basic steps in the photosynthetic process. All complexes are based on ruthenium(II)-trisbipyridine as photosensitizer, that is covalently linked to electron donors or electron or energy acceptors. The photochemical reactions were studied with time resolved transient absorption and emission measurements. In the complexes that mimic the donor side of Photosystem II, where a manganese cluster together with tyrosine catalyses the oxidation of water, intramolecular electron transfer was found to occur from Mn(II) or tyrosine to photo-oxidized Ru(III). Studies of a series of Ru(II)-Mn(II) complexes gave information of the quenching of the Ru(II) excited state by the coordinated Mn(II), which is important for the development of multi-nuclear Ru(II)-Mn complexes. In the supramolecular triad, PTZ-Ru 2+ -Q, the charge separated state, PTZ +• -Ru 2+ -Q −• , was rapidly formed, and further development where a second electron acceptor is linked to quinone is planned. Ultra fast energy transfer (τ<200 fs), was obtained between ruthenium(II) and osmium(II) in a small artificial antenna fragment. Fast and efficient energy transfer is important in larger antennas or photonic wires where a rapid energy transfer is desired over a large distance