Avaliação de impactos ambientais e alimentares de plantas geneticamente modificadas (PGM): uma proposta metodológica.

2009

Diversidade de bactérias diazotróficas endofíticas de mangue vermelho (Rihizophora mangle)e avaliação do potencial biotecnológico.

2009

Bioprospecção de actinobactérias rizosféricas de milho (Zea mays L.) com atividade antifúngica.

2009

Degradação da proteína Cry1Ac de Bacillus thuringiensis por bactérias de solo de cultura do algodão transgênico e convencional (Gossypium hirsutum).

2009

Implications of low breakdown voltage of component subcells on external quantum efficiency measurements of multijunction solar cells

The electrical and optical coupling between subcells in a multijunction solar cell affects its external quantum efficiency (EQE) measurement. In this study, we show how a low breakdown voltage of a component subcell impacts the EQE determination of a multijunction solar cell and demands the use of a finely adjusted external voltage bias. The optimum voltage bias for the EQE measurement of a Ge subcell in two different GaInP/GaInAs/Ge triple-junction solar cells is determined both by sweeping the external voltage bias and by tracing the I–V curve under the same light bias conditions applied during the EQE measurement. It is shown that the I–V curve gives rapid and valuable information about the adequate light and voltage bias needed, and also helps to detect problems associated with non-ideal I–V curves that might affect the EQE measurement. The results also show that, if a non-optimum voltage bias is applied, a measurement artifact can result. Only when the problems associated with a non-ideal I–V curve and/or a low breakdown voltage have been discarded, the measurement artifacts, if any, can be attributed to other effects such as luminescent coupling between subcells.

Auditoria da gestão pública: diferenças de expectativas, qualidade e satisfação nas autarquias locais

O presente estudo baseou-se na avaliação dos factores mais influentes na percepção da qualidade da auditoria e satisfação dos Directores dos Serviços Financeiros das Autarquias Locais Portuguesas sujeitas a Certificação Legal de Contas. Aferir se existiam opiniões divergentes por região administrativa foi outro objectivo a que nos propusemos. Os resultados da pesquisa demonstram que os factores mais influentes são a especialização, o planeamento e trabalho de campo da empresa de auditoria. A percepção da qualidade de auditoria por Distrito/Região revela-se homogénea, ao invés da satisfação em relação à actividade de auditoria. Tendo em conta os resultados obtidos, a auditoria deverá equacionar o alargamento do seu campo de actuação, reorientar o seu papel, reforçar a comunicação e especialização no sector, por forma a potenciar a responsabilização, avaliação e apoio na tomada de decisão na gestão dos dinheiros públicos e, por outro lado, harmonizar as expectactivas entre auditado e auditor. /ABSTRACT: The present study was based on the assessment of the most influential factors in the perception of audit quality and satisfaction of the Directors of Financial Services of Portuguese Local Government subject to the Statutory Auditors. To assess whether there were differing opinions by administrative region was another goal we set ourselves. The survey results demonstrate that the most influential factors are the expertise, the planning and fieldwork of the audit firm. The perception of audit quality by District I Region proves to be homogeneous, rather than satisfaction with the audit work. Given the results, the audit should consider extending its scope to act, to reorient their role, to strengthen the communication and expertise in the sector in order to enhance accountability, assessment and support in decision making in the management of public resources and, secondly, to harmonize expectations between auditee and auditor.

Specific shear-dependent viscoelastic third-grade fluid model

A specific modified constitutive equation for a third-grade fluid is proposed so that the model be suitable for applications where shear-thinning or shear-thickening may occur. For that, we use the Cosserat theory approach reducing the exact three-dimensional equations to a system depending only on time and on a single spatial variable. This one-dimensional system is obtained by integrating the linear momentum equation over the cross-section of the tube, taking a velocity field approximation provided by the Cosserat theory. From this reduced system, we obtain the unsteady equations for the wall shear stress and mean pressure gradient depending on the volume flow rate, Womersley number, viscoelastic coefficient and flow index over a finite section of the tube geometry with constant circular cross-section.

Processos erosivos em áreas de afloramento do sistema Aqüífero Guarani no Brasil.

2008

Controle dos processos erosivos em áreas de afloramento do Aqüífero Guarani no Brasil.

2008