9,755 research outputs found
Dynamics of localized spins coupled to the conduction electrons with charge/spin currents
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 between them. The equations of motion for the
localized spins are derived exactly up to , 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
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
O programa nacional de fortalecimento da agricultura familiar no Brasil: uma análise sobre a distribuição regional e setorial dos recursos.
No Brasil, as polĂticas pĂşblicas para o espaço rural sempre tenderam a priorizar a agricultura patronal, em detrimento dos agricultores familiares. Todavia, os estudos realizados pelos ĂłrgĂŁos FAO - INCRA deram subsĂdio para a criação do Programa Nacional de Fortalecimento da Agricultura Familiar (PRONAF), resultando em um novo direcionamento dos investimentos pĂşblicos, os quais passaram a contemplar o segmento dos agricultores familiares. Entende-se o PRONAF como uma polĂtica nĂŁo-compensatĂłria, que, apesar de seus problemas, tem contribuĂdo de fato para mudanças e melhorias no espaço agrário brasileiro. Desde sua criação no final da dĂ©cada de 1990, o PRONAF passou por várias mudanças em sua estrutura administrativa e operacional, a fim de alcançar seus objetivos e adequar-se face a complexa realidade social agrária brasileira. Sendo assim, o presente estudo visa discutir as ações do Estado por meio desse Programa, a partir de suas linhas de atuação, bem como analisar a distribuição de suas concessões de crĂ©dito regional e setorialmente. Assim, os procedimentos metodolĂłgicos utilizados para a realização deste trabalho compreendem pesquisa bibliográfica e documental, alĂ©m de pesquisa em fontes secundárias, no intuito de obter dados e informações relevantes para a análise das relações sociais estabelecidas em meio a esse processo de concretização e espacialização desse Programa. Dentre as implicações do PRONAF pode-se notar em âmbito nacional, uma diminuição da disparidade regional brasileira, bem como a preocupação que o Programa tem demonstrado com os aspectos socioculturais locais e regionais, como forma de garantir que seus investimentos perpassem a dimensĂŁo econĂ´mica, mas valorize outras dimensões, a exemplo dos elementos culturais
Drawing close: on visual engagements in fieldwork, drawing workshops and the anthropological imagination
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
Rapid detection of microorganisms by peptide nucleic acids
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
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
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
The occurrence of Lozano's goby Pomatoschistus Lozanoi (De Buen, 1923) (Pisces, gobiidae) on the Portughese Coast
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