1,299 research outputs found

    Application of molecular dynamics techniques and luminescent probes to the study of glass structure: the SiO2–GeO2 case

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    In this paper, we report on the results obtained from molecular dynamic simulation of a Eu3+-doped germanosilicate glass. This simulation provides further information on the structure. In particular it reveals a homogeneous distribution of SiO4 and GeO4 units, a decrease of defects compared to SiO2 and GeO2 glasses, and a trend to clustering of the doping ions. Using the modified crystal-field theory, the luminescence spectroscopic properties have been computed and comparison with experimental data has allowed a correlation of the spectral features with two main types of local environment depending on the coordination number and on the medium-range arrangement around the doping ions

    Girls’ and women’s education within Unesco and the World Bank, 1945–2000

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    By 2000, girls’ and women’s education was a priority for international development organisations. While studies have examined the impact of recent campaigns and programmes, there has been less exploration of ideas about girls’ and women’s education within development thought in the immediate post?colonial period, and the political mechanisms through which this came to be a global concern. Through a study of policy documents, this paper investigates how the education of girls and women came to be prioritised within the two principle UN agencies involved with education since 1945, the World Bank and Unesco. A shift in priorities is evident, from ensuring formal rights and improving the status of women, to expanding the productive capacities of women, fertility control and poverty reduction. While the ascendance of human capital theory provided a space for a new perception of the role of women’s education in development, in other policy arenas women’s education was central to exploring more substantive, rights?based notions of gender equality. Ultimately, the goal of improving girls’ and women’s education fitted into diverse development agendas, paving the way for it to become a global development priority

    The evolution of new party systems: voter learning and electoral systems

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    How do new party systems evolve over time? This article argues that party system evolution requires the solution of coordination problems that voters face in early elections; this happens through a learning mechanism. Elections reveal information to voters, who update their beliefs about party viability and the distribution of voters’ preferences and adjust their behaviour. The institutional setting, however, strongly conditions the pace of learning. Restrictive electoral systems (single-member district) accelerate learning through the harsh penalties they impose on miscoordination, while permissive ones (proportional representation) prolong it. Testing the argument on a district-level dataset in new democracies provides ample support; voters learn to cast fewer wasted votes over time and this happens faster in single-member district systems. The findings point to a trade-off between consolidation and representation; while party system evolution is facilitated by restrictive electoral systems, the presence of distinct social groups in the political arena is better served by permissive ones

    Rare-earth-activated glasses for solar energy conversion

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    The solar cells efficiency may be improved by better exploitation of the solar spectrum, making use of the down-conversion mechanism, where one high energy photon is cut into two low energy photons. The choice of the matrix is a crucial point to obtain an efficient down-conversion process with rare-earth ions. When energy transfer between rare earth ions is used to activate this process, high emission and absorption cross sections as well as low cut-off phonon energy are mandatory. In this paper we present some results concerning 70SiO2-30HfO2 glass ceramic planar waveguides co-activated by Tb3+/Yb3+ ions, fabricated by sol gel route using a top-down approach, and a bulk fluoride glass of molar composition 70ZrF4 23.5LaF3 0.5AlF3 6GaF3 co-activated by Pr3+/Yb3+ ion. Attention is focused on the assessment of the energy transfer efficiency between the two couples of rare earth ions in the different hosts

    The workings of the single member plurality electoral system in India and the need for reform

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    India uses single member plurality system (SMPS) to elect the members of the lower house of its national parliament and the state assemblies. Under SMPS, elections are conducted for separate geographical areas, known as constituencies or districts, and the electors cast one vote each for a candidate with the winner being the candidate who gets the plurality of votes. SMPS is traditionally defended primarily on the grounds of simplicity and its tendency to produce winning candidates, which promotes a link between constituents and their representatives. It tends to provide a clear-cut choice for voters between two main parties, and is expected to gives rise to single-party rather than coalition governments. It also has the benefit of excluding extremist parties from gaining representation, unless their support is geographically concentrated

    Declining partisan representation at the sub-national level: assessing and explaining the strengthening of local lists in Italian municipalities (1995–2014)

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    In Western democracies political representation at the national level is still dominated by (old and new) political parties. This article shows that, instead, the representative role of parties may have declined at the local level. In Italy, for instance, the average share of municipal seats held by non-partisan councillors has almost tripled in the last 20 years. By using an original data set, this article classifies different types of Italian local lists, assesses their relationship with traditional parties and explains territorial variation in their success. The results suggest that local lists have become substantially stronger in small municipalities, in regions characterised by weak or declining political subcultures and where regionalist parties are absent or irrelevant. Finally, contrary to the expectation that declining partisanship is linked to modernisation processes and direct civic engagement, local lists have achieved their best results in the less developed areas of the country
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