Elevated temperature induced dispersion phenomena in Ba1-xNaxTi1-xNbxO3

Purpose: of this paper was to investigate features of the dispersion of dielectric permittivity induced by elevated temperature (473K-723K) in polycrystalline solid solution of Ba1-xNaxTi1-xNbxO3 (for x=0.3 and x=0.4). Design/methodology/approach: used to perform this purpose was dielectric spectroscopy application to measure dielectric and electric parameters within the frequency range (20Hz-1MHz). Findings: Analysis of temperature and frequency dependences of real (ε’) and imaginary (ε”) parts of dielectric permittivity had pointed out on relaxor type of dielectric behaviour for both investigated samples in paraelectric phase. The thermal activation energy values of ac conductivity (for 100Hz) are similar to those of semiconductors. Values of ε’ for both materials (x=0.3, x=0.4) are consistent with literature quotations. Thus the polarisation behaviour of our materials seems to be similar to those described in the literature. Different behaviour of dielectric energy losses is postulated as originating from differences of samples microstructure. Research limitations/implications: Further investigations should be carried out in the range of low temperatures (down to 100K) and within a broaden frequency range (up to 1.8GHz) in order to establish the influence of chemical structure on ferroelectric-paraelectric phase transition. Originality/value: Dielectric properties for two new material prepared from nanopowders of BaTiO3 and NaNbO3 were described

Disruption Or Convention? A Process-based Explanation Of Divergent Repertoires Of Contention Among Opponents To Low-level Radioactive Waste Disposal Sites

Violence, disruption and convention constitute three well established categories of collective action repertoires available to contemporary social movements. What factors shape differences in repertoire selection across social movement groups? I take a process-based approach to answer this question, examining two grassroots opposition movements to the disposal of low-level radioactive waste in the United States. The two rural New York State counties I consider each faced a state-imposed low-level radioactive waste site proposal in 1988. Activists in each county mounted vigorous collective opposition to the proposed facility, while exhibiting distinct repertoires of collective action. Activists in Allegany County pursued disruptive civil disobedience, while activists in Cortland County pursued a conventional repertoire of citizen lobbying and litigation efforts. Similarities across a variety of demographic, political, and social characteristics in these two counties leave the standard explanations for repertoire selection put forth in the social movement literature wanting. I argue that the relationship developed between the respective county governments and citizen activists during the waste-site proposal dispute had a dramatic effect on the dominant repertoire of collective action adopted by each community. More specifically, identifying the presence or absence of the social mechanism of brokerage between local government and activists is crucial to understanding the different trajectories of these movement groups. This article highlights the utility of fine-grained process-based analysis as a complement to variable-based approaches for explaining social movement activity, and the importance of the mechanism of brokerage among local government and activists for understanding bottom-up movements responding to proximate grievances, such as the environmental justice movement. Adapted from the source document

Real-world corticosteroid use in severe pneumonia: a propensity-score-matched study

Background: Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality worldwide despite correct antibiotic use. Corticosteroids have long been evaluated as a treatment option, but heterogeneous effects on survival have precluded their widespread implementation. We aimed to evaluate whether corticosteroids might improve clinical outcomes in patients with severe CAP and high inflammatory responses. Study design and methods: We analyzed two prospective observational cohorts of patients with CAP in Barcelona and Rome who were admitted to intensive care with a high inflammatory response. Propensity score (PS) matching was used to obtain balance among the baseline variables in both groups, and we excluded patients with viral pneumonia or who received hydrocortisone. Results: Of the 610 patients admitted with severe CAP, 198 (32%) received corticosteroids and 387 had major criteria for severe CAP. All patients had a baseline serum C-reactive protein above 15 mg/dL. Patients who received corticosteroids were more commonly male, had more comorbidities (e.g., cancer or chronic obstructive pulmonary disease), and presented with significantly higher sequential organ failure assessment scores. Eighty-nine patients met major severity criteria (invasive mechanical ventilation and/or septic shock) and were matched per group. Twenty-eight-day mortality was lower among patients receiving corticosteroids (16 patients, 18%) than among those not receiving them (28 patients, 31%; p = 0.037). After PS matching, corticosteroid therapy reduced the 28-day mortality risk in patients who met major severity criteria (hazard ratio (HR) 0.53, 95% confidence interval (CI) 0.29–0.98) (p = 0.043). In patients who did not meet major severity criteria, no benefits were observed with corticosteroid use (HR 0.88 (95%CI 0.32–2.36). Conclusions: Corticosteroid treatment may be of benefit for patients with CAP who have septic shock and/or a high inflammatory response and requirement for invasive mechanical ventilation. Corticosteroids appear to have no impact on mortality when these features are not present

Internal friction phenomena in composites based on PZT-type ferroelectric powder and ferrites

The aim of the work was to determine the phenomena of internal friction (mechanical losses) occurring in ferroelectric-ferromagnetic composites created based on PZT-type ferroelectric powder and ferrite. The composites were obtained using ceramic powders – multi-component PZT-type solid solutions with ferroelectric properties. Their magnetic component included zinc-nickel powder Ni0.64Zn0.36Fe2O4. 30 × 10 × 1 mm3 test specimens were obtained using free sintering. Temperature Q -1(T) and amplitude Q -1(ε) internal friction dependencies were determined. Wide high temperature maxima were observed with regard to the internal friction temperature dependencies obtained for the tested specimens. The conducted measurements of amplitude (isothermal) dependencies of internal friction Q -1(ε) for the tested composites have allowed for interpreting the previously observed maximum on the temperature dependencies of internal friction

Análise da legitimidade sociopolítica e cognitiva da controladoria no Brasil

Em diferentes partes do mundo têm sido realizados esforços na busca de legitimidade e identidade para a controladoria, a partir deste contexto emerge a pergunta de pesquisa: Qual a identidade da disciplina Controladoria no Brasil? Para responder esta pergunta, a presente pesquisa baseia-se nos estudos sobre legitimidade e tem como objetivo identificar e analisar a legitimidade sociopolítica (Zimmerman & Zeitz, 2002; Aldrich, 1999) e cognitiva (Scott, 2001; Zimmerman & Zeitz, 2002) da controladoria no Brasil. Para atingir o objetivo proposto, em relação à legitimidade sociopolítica, foram pesquisados documentos, normas e resoluções de órgãos oficiais e de representação de classe, e com a finalidade de analisar a legitimidade cognitiva, as publicações nas principais revistas de contabilidade, congressos e seminários, disciplinas de controladoria, livros e manuais. Os resultados mostram que a controladoria no Brasil apresenta legitimidade sociopolítica, ou seja, possui organismos e normas próprias, contudo, necessita melhorar os níveis de organização e desenvolvimento, assim como ocorre nos Estados Unidos e Alemanha. Observa-se também que a legitimidade cognitiva cresceu na publicação de livros e manuais, a disciplina de controladoria está presente na maioria dos cursos de Ciências Contábeis, e apresenta oportunidades de aperfeiçoamento, principalmente no que se refere a publicações em periódicos