998 resultados para Silver Latin Epic


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Democratisation presents opportunities and threats to non-governmental organisations (NGOs). Greater openness associated with democratic regimes provides opportunities for participation and influence not previously available. At the same time, increasing state capacity may threaten the continued relevance of NGOs. The article examines the Environment and Natural Resources Foundation (FARN) of Argentina and the Regional Environmental Center (REC) of eastern Europe to assess environmental support organisations in post-authoritarian contexts. The aims of the article are to identify opportunities and threats to environmental support organisations and to examine the strategies they adopt to advance their interests and achieve their goals.

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A new method was investigated to produce new multiscale fibrous nanocomposites comprised of titanium oxide (TiO2) nanofibers and silver (Ag) nanoparticles (NPs). The process involved electrospinning TiO2 precursor solution containing colloidal solution of Ag NPs, and organic solvent (dimethyl-n′n-formamide) to fabricate a porous, nonwoven, free-standing nanofiber mesh. Postprocess heating of the electrospun nanofibers entailed calcination in air environment at 500°C for 3 h. Microemulsion processing was used to generate NPs of Ag in a monodispersed distribution throughout the colloidal solution. X-ray diffraction data were consistent with the anatase phase of TiO2, while transmission electron microscopy and hydrogen desorption measurements revealed a very porous microstructure. It was demonstrated that NP colloidal stability is solvent dependent. It is anticipated that incorporation of metal particles in nanofibers will lead to enhanced photocurrent generation, when used in functional devices.

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The ionic liquid (IL) 2-butylthiolonium bis(trifluoromethanesulfonyl)amide, [mimSBu][NTf2], facilitates the efficient extraction of silver(i) from aqueous media via interaction with both the cation and anion components of the IL. Studies with a conventional aqueous-IL two phase system as well as microextraction of silver(i) by a thick IL film adhered to an electrode monitored in situ by cyclic voltammetry, established that [mimSBu][NTf2] can extract electroactive silver(i) ions from an aqueous solution. The pH of the aqueous phase decreases upon addition of [mimSBu]+, which is attributed to partial release of the hydrogen attached to the N(3) nitrogen atom of the imidazolium ring. The presence of silver(i) further increase the acidity of the aqueous phase as a consequence of coordination with the IL cation component. Voltammetric and 1H and 13C NMR techniques have been used to establish the nature of the silver(i) complexes extracted, and show that the form of interaction with the IL differs from that outlined previously for the extraction of copper(ii). Insights on the competition established when silver(i) is extracted in the presence of copper(ii) are provided. Finally, it is noted that metallic silver can be directly electrodeposited at the electrode surface after extraction of silver(i) into [mimSBu][NTf2] and that back extraction of silver(i) into aqueous media is achieved by addition of an acidic aqueous solution.

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We describe a simple experiment which allows unequivocal determination of optical phase change upon reflection of light at the mica-silver interface. While the physical origin of such a phase change at the dielectric-metal interface is well understood to lie in absorption of electromagnetic energy by the metal, inconsistency and ambiguity has persisted as to what its sign and magnitude should be in the field of thin film optics. Most commonly, it has been assigned to be negative for mathematical convenience or just arbitrarily. Our finding shows that with the convention exp(-iωt) for time dependence of the electromagnetic wave, the phase change at the interface between mica and the thin silver film is necessarily positive and its magnitude falls between π and 3π/2 for silver thicknesses down to nanometres. This gives a physically reasonable correspondence to an increased equivalent thickness of the dielectric material, and it clarifies the assignment of interference orders in the harmonic series in a spectrum.

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Background/Objectives: This study evaluates the feasibility among preschoolers of the 224-h dietary recalls (24-HDRs) method combined with a food-recording booklet (FRB), using EPIC-Soft pc-program for the 24-HDR (the software developed to conduct 24-HDRs in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study).
Subjects/Methods: A total of 20 and 25 (4- to 5-year-old) children were recruited, as a convenience sample, through worksites or day or healthcare in Denmark and Spain, respectively. One parent (or both parents together) completed two face-to-face 24- HDR, combined with an optional use of a FRB. Feasibility was evaluated by evaluation questionnaires completed by parents and interviewers.
Results: The face-to-face interviews were primarily conducted with the mothers. The FRB was used by 90% of the participants, and proxy persons, other than the parent, were also involved; involvement of proxy persons seems necessary in a majority of the recalls in both the countries.
Conclusions: The results suggest that 224-HDR with one parent combined with a FRB is feasible for registering preschoolers’ diet. An FRB and/or information from proxy persons, other than the parent, is needed for a majority of the parents. In future studies, it may be beneficial to develop the FRB more like a structured food record (FR), which might, in principle, change the method to a one-day FR method from more than a 24-HDR method. It is recommended then to further investigate the use of EPIC-Soft as a data-entry tool.