2,207 research outputs found

    Reduced Density-Matrix Functional Theory: correlation and spectroscopy

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    In this work we explore the performance of approximations to electron correlation in reduced density-matrix functional theory (RDMFT) and of approximations to the observables calculated within this theory. Our analysis focuses on the calculation of total energies, occupation numbers, removal/addition energies, and spectral functions. We use the exactly solvable Hubbard molecule at 1/4 and 1/2 filling as test systems. This allows us to analyze the underlying physics and to elucidate the origin of the observed trends. For comparison we also report the results of the GWGW approximation, where the self-energy functional is approximated, but no further hypothesis are made concerning the approximations of the observables. In particular we focus on the atomic limit, where the two sites of the molecule are pulled apart and electrons localize on either site with equal probability, unless a small perturbation is present: this is the regime of strong electron correlation. In this limit, using the Hubbard molecule at 1/2 filling with or without a spin-symmetry-broken ground state, allows us to explore how degeneracies and spin-symmetry breaking are treated in RDMFT. We find that, within the used approximations, neither in RDMFT nor in GWGW the signature of strong correlation are present in the spin-singlet ground state, whereas both give the exact result for the spin-symmetry broken case. Moreover we show how the spectroscopic properties change from one spin structure to the other. Our findings can be generalized to other situations, which allows us to make connections to real materials and experiment

    Indian nurses in Italy: a qualitative study of their professional and social integration

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    AIMS AND OBJECTIVES: To investigate the lived subjective experiences of immigrant Indian nurses in Italy and specifically their professional and social integration. BACKGROUND: To study the worldwide, nursing flux is a health priority in the globalised world. The growth in migration trends among nurses, not only from Philippines or India, has proliferated in recent years. The research on nurses' mobility for Southern European countries is underexplored, and in Italy, the out-migration flows of Indian nurses were never analysed. DESIGN: Qualitative methodological approach. METHODS: Semi-structured interviews (n = 20) were completed with Indian clinical nurses working in Italy for more than one year mainly in private organisations. A purposive sampling technique was used for recruitment. The data were then content-analysed using an inductive method. RESULTS: The findings were categorised into four themes: (1) aspects of professional integration and working experience, (2) intra- and interprofessional relationships and perceptions of the IPASVI Regulatory Nursing Board, (3) initial nursing education and continuous professional development and (4) perceptions of social integration. CONCLUSION: The results show that for Indian nurses in Italy emigration is important to gain opportunities to expand economic and social privileges as well as escape from historical assumptions of stigma associated with nursing work, especially for women. However, these conclusions have to be seen in wider socio-cultural complexities that are at the basis of transnational fluxes (Prescott & Nichter ). RELEVANCE TO CLINICAL PRACTICE: The research offers an insight into the complicated reasons for Indian nurses out-migration to Italy. Without comprehending the interwoven textures of the political and social relations that are continually constructed and re-constructed among different nations, it is difficult to understand nurses out-migration and consequently have a better and safer collaborative teamwork in the host countries

    Un-rooted grafted cuttings for eggplant plug-transplant production and shipping: simulated transportation and healing requirements

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    Vegetable grafting is one of the most effective eco-friendly techniques to overcome pests and soilborne diseases in modern cropping systems of fruiting vegetables. Due to the increased farmers’ preference for grafted seedlings of high quality and better performance, the use of vegetable grafted plants is rapidly spreading and expanding over the world and intensive researches on new commercial production systems are under way. However, in many areas of the world, due to the high cost of skilled manpower, the use of grafted plug plants is still limited causing a relatively slow development of the grafting nursery industry. The aim of this work was to evaluate a possible use of un-rooted grafted cuttings as means of propagation and distribution of eggplant transplants. In this experiment, un-rooted grafted eggplant cuttings (‘Birgah’ eggplant scion with Solanum torvum rootstock) harvested after diverse healing times [0 (DIH 0), 1 (DIH 1), 3 (DIH 3), 5 (DIH 5), or 7 (DIH 7) days in healing] were exposed to 20, 14 and 8°C ‘simulated transportation temperature’ and dark condition in a growth chamber for 72 hours. After 72 hours of the simulated transportation treatment, all un‐rooted grafted cuttings were transferred into the greenhouse for rooting. The results showed that S. torvum is a suitable rootstock for applying the un-rooted grafted cutting propagation technique. All grafted cuttings reached the grafting success (100%) and all un-rooted grafted cuttings developed roots at the end of the rooting stage (100%). Regardless of the simulated shipping conditions, the treatment DIH 0 gave the best results in terms of number of leaves after rooting (3.8 leaves), shoot fresh and dry weight after 7 days of growth (3.92 and 0.46 g, respectively), fresh weight of the roots (1.34 g), and plantlet visual quality of the finished plug transplants (8.8). This innovative production/ shipping method might be successfully used in areas where local nurseries do not have high grafting ability
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