405 research outputs found

    Doctoral graduates of the Social Sciences and Humanities career paths : the case of Portugal

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    While it is said that the mobility of PhD graduates would be encouraged outside the aca- demic environment, they continue to work mostly within higher education and research. This paper explores the professional life courses of 25 PhD Portuguese graduates in the Social Scienc- esand Humanities in order to understand the process according to which they move or not from one sector to another. A first dataset results from an online survey of SSH doctoral graduates. A second dataset is made of the transcripts of 25 in-depth interviews with doctorate holders. The paper sheds light on their motivation and expectation, among other expectation emerging over the course of their doctoral research

    Comparison of educational facilitation approaches for Grade R English Additional Language learning in rural Mpumalanga

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    The Early Childhood Development Manager in Mpumalanga is faced with the problem of providing evidence-based guidance of the best facilitation approach in the Grade R context. An investigation on the effect of   facilitation, i.e. play-based or formal instruction, on Grade R performance scores in English Additional Language (EAL) learning was conducted.  Literature findings attest to formal learning contributing to better   performance scores than play-based learning, yet most rural schools in Mpumalanga use the play-based approach. The English Language Proficiency (ELP) standards assessment tool is reported to have no cultural bias and was used to collect the data. The tool assessed learners’ listening and speaking skills in EAL. A quantitative methodology was followed, using a static two-group comparison design. Participants in the two groups were matched according to age and all had a similar exposure period to EAL learning, a rural upbringing, poverty level, and all were mainstream  learners. Inter-rater reliability was obtained since two raters assessed learners’ proficiency in EAL skills. A one-way Analysis of Variance (ANOVA) was used to analyse the data. It was found that the formal based approach contributed to better EAL scores when compared to the play-based  approach. Implications for practice are discussed.Keywords: EAL learning; ELP standards assessment tool; formal  instruction;Grade R facilitation; learners’ first language; play-based approach

    Photon emission as a source of coherent behaviour of polaritons

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    We show that the combined effect of photon emission and Coulomb interactions may drive an exciton-polariton system towards a dynamical coherent state, even without phonon thermalization or any other relaxation mechanism. Exact diagonalization results for a finite system (a multilevel quantum dot interacting with the lowest energy photon mode of a microcavity) are presented in support to this statement

    A network approach to studying research programmes : mobilizing and coordinating public responses to HIV/AIDS

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    Based on the analysis of the Medical and Public Health Research programme (Commission of the European Communities), the paper shows how new scientific communities are created in response to the HIV/AIDS problem. We analyze how actors are mobilized (three mobilization modes : public impetus, scientists'initiative, scientists' initiative with public networking) and how their work is coordinated. We defend the hypothesis that these new scientific communities are flexible cooperation networks. In the case of AIDS research, there are only a limited number of network types (the data collection structure, the forum, the thematic partition with harmonization of research practices, the starred around a central facility). The coordination of these scientific cooperative networks passes through fixed and circulating intermediaries. The management of these intermediaries is a major activity for involved actors. thus, our aim is not to study the wider social context, but to analyze networking in response to policy initiatives. (Résumé d'auteur

    Photon-mediated interactions near a Dirac photonic crystal slab

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    Dirac energy-dispersions are responsible of the extraordinary transport properties of graphene. This motivated the quest for engineering such energy dispersions also in photonics, where they have been predicted to lead to many exciting phenomena. One paradigmatic example is the possibility of obtaining power-law, decoherence-free, photon-mediated interactions between quantum emitters when they interact with such photonic baths. This prediction, however, has been obtained either by using toy-model baths, which neglect polarization effects, or by restricting the emitter position to high-symmetry points of the unit cell in the case of realistic structures. Here, we develop a semi-analytical theory of dipole radiation near photonic Dirac points in realistic structures that allows us to compute the effective photon-mediated interactions along the whole unit cell. Using this theory, we are able to find the positions that maximize the emitter interactions and their range, finding a trade-off between them. Besides, using the polarization degree of freedom, we also find positions where the nature of the collective interactions change from being coherent to dissipative ones. Thus, our results significantly improve the knowledge of Dirac light-matter interfaces, and can serve as a guidance for future experimental designs.Comment: 12 figures, 19 page

    Quantum correlations between two distant cavity QED systems coupled by a mechanical resonator

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    Achieving quantum correlations between two distant systems is a desirable feature for quantum networking. In this work, we study a system composed of two quantum emitter-cavity subsystems spatially separated. A mechanical resonator couples to either both quantum emitters or both cavities leading to quantum correlations between both subsystems such as non-local light-matter dressed states and cavity-cavity normal mode splitting. These indirect couplings can be explained by an effective Hamiltonian for large energy detuning between the mechanical resonator and the atoms/cavities. Moreover, it is found optimal conditions for the physical parameters of the system in order to maximize the entanglement of such phonon-mediated couplings

    Método de diferencias finitas en el dominio de las frecuencias para cristales fotónicos 1d y 2d

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    En este trabajo se estudian los modos electromagnéticos en cristales fotónicos uno-dimensionales y dos-dimensionales (1D y 2D) a través del método de diferencias finitas en el dominio de las frecuencias FDFD. Los diagramas de bandas son calculados para cristales 1D regulares y con defecto, al igual que sus perfiles de intensidad electromagnética. De igual manera se calculan los diagramas de bandas y perfiles de intensidad para cristales 2D regulares en redes hexagonal y cuadrada. Nuestros cálculos son comparados con los obtenidos en el software MPB proporcionado por el MIT y basado en el método de expansión de ondas planas.In this work we study the electromagnetic modes in one-dimensional and two-dimensional photonic crystals through finite difference frequency domain method. The band diagrams and the intensity profiles are calculated for one-dimensional photonic crystal with a defect, and for two-dimensional photonic crystals in hexagonal and square lattices. Our calculations are compared with simulations made with MPB software based on plane wave expansion method
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