1,721,025 research outputs found
Ethical leadership and service orientation in social care workers: Team engagement and service climate as sequential mediators
No full textUsing the Job Demands - Resources (JDR) model and the service climate framework, this study investigates the simple and sequential mediation of team engagement and service climate between ethical leadership and two components of service orientation (internal cooperative behaviors and service competence). An online survey was conducted in an Italian social cooperative which offers services for elderly people, people with disabilities, minors, and kindergartens, and involved 1,221 employees, working in 89 residential and day care centers. Results, examined at center level, show that team engagement and the service climate sequentially mediate the relationship between ethical leadership and employees' service competence; in addition, team engagement mediates between ethical leadership and internal cooperative behaviors. Contrary to expectations, ethical leadership was not directly related to any service orientation component. In conclusion, results confirm the JDR model and offer suggestions to extend and integrate the service climate framework with the JDR model
Bridging the fields of nanoscience and toxicology: nanoparticle impact on biological models
No full textIn the emerging area of nanotechnology a key issue is related to the potential impacts of the novel nanomaterials on the environment and human health so that this technology can be used with minimal risk. Specifically designed to combine on a single structure multipurpose tags and properties, nanomaterials need a comprehensive characterization of both chemicophysical properties and toxicological evaluation, which is a challenging endeavor: the in vitro toxicity assays that are employed for nanotoxicity assessments do not accurately predict in vivo response. To overcome these limitations and gain a deeper understanding of nanoparticle-cell interactions, we have employed cnidarian models, in particular the freshwater polyp Hydra vulgaris, not opposed to more complex and evoluted systems, but to add valuable information, at an intermediate level between prokaryotes and vertebrates, on both cytoxicity and on pollution affecting the environment. By testing CdSe/CdS core shell nanocrystals in vivo, at whole animal level, we investigated the impact of their properties on uptake, accumulation, biodistribution, elicitation of behavioural responses. Spanning from animal to cell biology, we provide an analysis on metal based and semiconductor NC, discussing the crucial role played by the synthesis route and chemical surface on the toxicity for living organisms
Calcium and phosphorous enrichment of porous niobium and titanium oxides for biomaterial applications
No full textAnodic oxidation of niobium has been investigated in an electrolyte solution containing calcium phosphate and calcium acetate. The oxide layer morphology has been determined by combining 3D Atomic Force Microscopy images and cross-sectional Field Emission SEM measurements. The surface sensitivity of high-resolution X-ray Photoemission Spectroscopy has been exploited to evaluate the chemical composition of the outermost oxide surface, a key feature in view of implant development. Anodic Spark Deposition (ASD) results in the formation of micrometer-thick oxide layers showing a porous morphology suitable for osseointegration purposes. Increasing the maximum potential attained during oxidation leads to an increase of the oxide thickness and pore size accompanied by a noticeable surface enrichment with calcium and phosphorus. Remarkably, a maximal Ca/P ratio of 1.8 was achieved for anodization at 250 V, promising for osseointegration thanks to the similarity with hydroxyapatite stoichiometry. Parallel experiments performed on titanium under the same conditions indicated a maximal Ca/P ratio of 1.3 and pores of smaller dimensions. The comparative analysis suggests that niobium may represent a promising alternative to titanium to be explored for implant development
Resonant ionization plus Auger neutralization in the study of the electronic structure of clean semiconductor surfaces
No full textMetastable atom de-excitation spectroscopy results on the surfaces of clean semiconductors are shown. De-excitation occurs through resonant ionization followed by Auger neutralization. After a review of the results obtained on the clean surface of GaAs(110) at room temperature, the evolution of the Ge(111) effective surface density of states (SDOS) as a function of temperature is discussed on the basis of the temperature-induced surface structure transitions reported in literature by different authors. (C) 1998 Elsevier Science B.V. All rights reserved
A MDS study of the Yb/GaAs(110) interface
No full textMetastable deexcitation spectroscopy (MDS) was applied to the study of the growth of the Yb/GaAs(110) interface. MD spectra taken at different coverages, from 0.04 ML to 30 ML, revealed the progressive metallization of the overlayer. Absence of 4f emission allowed to observe, for the first time, VB features of the forming interface up to similar to 8 ML
Plasmonics of Au nanoparticles in a hot thermodynamic bath
No full textElectromagnetically-heated metal nanoparticles can be exploited as efficient heat sources at the nanoscale. The assessment of their temperature is, however, often performed indirectly by modelling their temperature-dependent dielectric response. Direct measurements of the optical properties of metallic nanoparticles in equilibrium with a thermodynamic bath provide a calibration of their thermo-optical response, to be exploited for refining current thermoplasmonic models or whenever direct temperature assessments are practically unfeasible. We investigated the plasmonic response of supported Au nanoparticles in a thermodynamic bath from room temperature to 350 °C. A model explicitly including the temperature-dependent dielectric function of the metal and finite-size corrections to the nanoparticles' permittivity correctly reproduced experimental data for temperatures up to 75 °C. The model accuracy gradually faded for higher temperatures. Introducing a temperature-dependent correction that effectively mimics a surface-scattering-like source of damping in the permittivity of the nanoparticles restored good agreement with the data. A finite-size thermodynamic effect such as surface premelting may be invoked to explain this effect
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Comparison of plant alternatives in a freight-terminal using stochastic discrete event simulation
No full textThe study presented in the paper is the result of a mandate to the Authors from the management of a freight-terminl located in a region in the North-East of Italy. The objective of the study, therefore, is to identify the most efficient configuration in term of costs and performance of internal container handling systems in among a set of possible solutions set by the designers. Given that in the freight-terminal there's a high level of stochasticity elements (hours of arrival and restarts of container vehicles, breakdowns of handling equipment, availability of operators, etc.) an effective and efficient modelling could not have disregarded this fundamental characteristic of the real system. For this reason the Authors decided to study the problem by the use of Discrete Event Simulation. The tools selected by the Authors for the construction of the model was Flexsim CT, whose graphics allow managers to exploit the prerogatives of management methodologies known as "visual management" in addition, of course, to the usual quantitative analysis that characterize the output of a correctly constructed DES model. Thanks to the study carried out, the managers were able to establish, among the solutions proposed, the scenario that involved 1 crane and 3 top loader was the one that allowed both the minimization of purchase and management costs of the yard than the reduction of expectations for handling equipment
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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