9,678 research outputs found

    Dynamics of localized spins coupled to the conduction electrons with charge/spin currents

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    The effects of the charge/spin currents of conduction electrons on the dynamics of the localized spins are studied in terms of the perturbation in the exchange coupling JKJ_{K} between them. The equations of motion for the localized spins are derived exactly up to O(JK2)O(J_{K}^2), and the equations for the two-spin system is solved numerically. It is found that the dynamics depends sensitively upon the relative magnitude of the charge and spin currents, i.e., it shows steady state, periodic motion, and even chaotic behavior. Extension to the multi-spin system and its implications including possible ``spin current detector'' are also discussed.Comment: 5 pages, 4 figures, REVTe

    ABC with a UNIX flavor

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    ABC is a simple, yet powerful, textual musical notation. This paper presents ABC::DT, a rule-based domain-specific language (Perl embedded), designed to simplify the creation of ABC processing tools. Inspired by the Unix philosophy, those tools intend to be simple and compositional in a Unix filters' way. From ABC::DT's rules we obtain an ABC processing tool whose main algorithm follows a traditional compiler architecture, thus consisting of three stages: 1) ABC parser (based on abcm2ps' parser), 2) ABC semantic transformation (associated with ABC attributes), 3) output generation (either a user defined or system provided ABC generator).(undefined)info:eu-repo/semantics/publishedVersio

    Drawing close: on visual engagements in fieldwork, drawing workshops and the anthropological imagination

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    Participatory visual methods are becoming the new hype in anthropology. Researchers tend to present participatory visual methods as attractive approaches to not only promote innovative research that engages informants in original and collaborative ways but to engage students eager to find bridges between the academic world and a world progressively addicted to visual consumerism. Unlike photographing and filming, doodling-sketching-drawing – participatory or not – is more about linear image mental processing and communicating (and thus somewhat akin to handwriting, lack of linguistic encoding and propositionality notwithstanding) than an “objective” visual method. Based on discussions from a workshop dedicated to “ethnographic drawing” in the University of Aberdeen, we propose to tackle some of the features of the drawing practice, hoping that its much-misunderstood potential as a knowledge tool helps us reconsider what anthropological understanding is.info:eu-repo/semantics/publishedVersio

    Contextual reasons for emigrants’ electoral participation in home country elections: The Portuguese case

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    Although emigrants represent an increasing share of the electoral population in many democracies not much is known about their participation in home country elections. Aiming at contributing to fulfil this gap, this article longitudinally and exploratory analyses the contextual factors of Portuguese emigrants’ participation in national elections (1976-2015), a country with one of the highest emigration rates of EU today. First, it presents a longitudinal analysis of the electoral participation of Portuguese emigrants, and then analyses the conditions underlying levels of participation. By using aggregate data covering the main fifteen destination countries, this study compares institutional, socio-economic and political contextual factors for voting. Findings indicate that the lack of political participation of emigrants is first demonstrated by the very low registration rates, although it varies according to the country, and that voting methods and socio-economic factors in the destination country are the most relevant to explain voting in home country elections.info:eu-repo/semantics/acceptedVersio

    Rapid detection of microorganisms by peptide nucleic acids

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    Peptide nucleic acid (PNA) molecules are DNA mimics, where the negatively charged sugarphosphate backbone is replaced by an achiral, neutral polyamide backbone formed by repetitive units of N–(2-aminoethyl) glycine. Due to their superior hybridization properties, PNA probes to detect pathogens by fluorescence in situ hybridization (FISH) have been challenging DNA probes over the last few years. In our lab, we have already designed and developed several new probes for the specific detection of bacterial species such as Helicobacter pylori, Cronobacter spp., Staphylococcus epidermidis, Salmonella spp. and Proteus spp. [1, 2]. During development and validation, probes are tested against several related species, and have been shown to be highly specific for the microorganisms of interest. All techniques were optimized in slides and then adapted for different types of samples, depending on the microorganism: H. pylori probe has been developed to work on gastric biopsies and will soon be tested in a clinical trial for a potentially commercial application; Cronobacter spp. is a major contaminant of milk-based powdered infant formula, and as such a probe to detect the pathogen after pre-enrichment of contaminated milk was devised; S. epidermidis, which is frequently present on the skin of humans, had methods developed for its identification in blood samples and catheters; and analysis of interest for Salmonella and Proteus spp. included pipes of drinking water distribution systems and urinary samples. Future work with PNA probes will involve simultaneous detection of several species in a single sample and quantitative signal detection by flow cytometry

    Techniques for colonial growth and protoplast production in Humicola grisea var. thermoidea

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    Humicola grisea is a thermophilic, cellulolytic fungus, with significant biotechnological potential for protein secretion. For convenient growth on solid medium, 70% reduction in colony diameter was achieved by the addition of 20 mM sodium citrate to modified Aspergillus complete medium (Pontecorvo et al. 1953, Adv. Genet. 5:141-238)

    Institutional and economic determinants of corporate social responsibility disclosure by banks: institutional perspectives

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    Purpose: This article explores the firm and country-level institutional forces that determine banks’ CSR reporting diversity, during the recent global financial crisis. Design/methodology/approach: Specifically, the present article assesses if economic and institutional conditions explain CSR disclosure strategies used by thirty listed and unlisted banks from six countries in the context of the recent 2007/2008 Global Financial Crisis. The annual reports and social responsibility reports of the largest banks in Canada, UK, France, Italy, Spain and Portugal were content analyzed. Findings: Findings suggest that economic factors do not influence CSR disclosure. Institutional factors associated with the legal environment, industry self-regulation and the organization’s commitments in maintaining a dialogue with relevant stakeholders are crucial elements in explaining CSR reporting. Consistent with the Dillard’s et al. (2004) model, CSR disclosure by banks not only stems from institutional legitimacy processes, but also from strategic ones. Practical implications: Findings highlight the importance of CSR regulation to properly monitor managers’ opportunistic use of CSR information and regulate assurance activities (regarding standards, their profession, or even assurance) to guarantee the reliability of CSR information. Originality/Value: The study makes two major contributions. First, it extends and modifies the model used by Chih et al. (2010). Second, drawn on the new institutional sociology, this study develops a theoretical framework that combines the multilevel model of the dynamic process of institutionalization, transposition, and deinstitutionalization of organizational practices developed by Dillard et al. (2004) with the Campbell’s (2007) theoretical framework of socially responsible behaviour. This theoretical framework incorporates a more inclusive social context, aligned with a more comprehensive sociology-based institutional theory (Dillard et al., 2004; Campbell, 2007), which has never been used in the CSR reporting literature hitherto.info:eu-repo/semantics/acceptedVersio
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