Gradient jump penalty stabilisation of spectral/hp element discretisation for under-resolved turbulence simulations

One of the strengths of the discontinuous Galerkin (DG) method has been its balance between accuracy and robustness, which stems from DG’s intrinsic (upwind) dissipation being biased towards high frequencies/wavenumbers. This is particularly useful in high Reynolds-number flow simulations where limitations on mesh resolution typically lead to potentially unstable under-resolved scales. In continuous Galerkin (CG) discretisations, similar properties are achievable through the addition of artificial diffusion, such as spectral vanishing viscosity (SVV). The latter, although recognised as very useful in CG-based high-fidelity turbulence simulations, has been observed to be sub-optimal when compared to DG at intermediate polynomials orders (P ≈ 3). In this paper we explore an alternative stabilisation approach by the introduction of a continuous interior penalty on the gradient discontinuity at elemental boundaries, which we refer to as a gradient jump penalisation (GJP). Analogous to DG methods, this introduces a penalisation at the elemental interfaces as opposed to the interior element stabilisation of SVV. Detailed eigenanalysis of the GJP approach shows its potential as equivalent (sometimes superior) to DG dissipation and hence superior to previous SVV approaches. Through eigenanalysis, a judicious choice of GJP’s P-dependent scaling parameter is made and found to be consistent with previous apriori error analysis. The favourable properties of the GJP stabilisation approach are also supported by turbulent flow simulations of the incompressible Navier-Stokes equation, as we achieve high-quality flow solutions at P = 3 using GJP, whereas SVV performs marginally worse at P = 5 with twice as many degrees of freedom in total

Motivations for high performance teams of information systems projects

As equipas de elevado desempenho apresentam características únicas que as diferenciam das restantes, sendo um dos aspetos fundamentais a motivação dos seus elementos. Neste trabalho são apresentados os resultados parciais de um estudo de caso focado no elevado desempenho das equipas de projetos de sistemas de informação. Muito concretamente, identifica-se um conjunto de aspetos que contribuem para a motivação dos elementos de uma equipa, de acordo com a sua própria perspetiva. Este trabalho visa proporcionar uma melhor compreensão dos aspetos que influenciam a motivação dos elementos das equipas de elevado desempenho e, assim, contribuir para o estudo e prática da gestão de projetos de sistemas de informação.High performance teams present unique characteristics that make them distinct from the others, being one of the fundamental aspects the motivation of its elements. In this paper are presented the partial results of a case study focused on high performance teams of information systems projects. Specifically, it is identified a set of aspects that contribute to the motivation of the team’s elements, according to their own perspective. This work aims to provide a better understanding of the aspects that influence the motivation of the elements for high performance teams and thus contribute to the study and practice of information systems project management.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Atributos de qualidade e funcionais de acessos do banco ativo de germoplasma de mangaba da Embrapa Tabuleiros Costeiros.

bitstream/item/145650/1/CT-71.pd

Taxonomic, structural diversity and carbon stocks in a gradient of island forests

Assessment of forest ecosystems and their services is seen as a key action for the advancement of biodiversity objectives, and to inform the development and implementation of related policies and planning. The Azorean forest is important for timber production, the protection of soil and water resources, and for its recreational and aesthetic value. However, its role in carbon accumulation has not been fully addressed. We assessed plant diversity, forest structure and carbon stocks in a gradient of three forest types (Natural Forest-NF; Exotic Woodland-EW and Production Forest-PF) in three of the Azores islands. We used biodiversity indices and found that NF harboured the highest plant diversity levels and PF the lowest. Diversity levels were lower for structural than for taxonomic data, particularly for PF. The highest tree carbon stock was found at EW in one of the islands, while PF consistently exhibited relatively high tree carbon stocks in the three islands. The largest soil carbon stocks were found at EW, while leaf litter carbon stocks were higher at PF. We concluded that NF play a fundamental role as plant diversity hotspots but have lower relevance as carbon stocks what might be associated with montane environmental conditions. PFs provide economic assets and act as carbon sinks, while EWs play a major role as carbon sinks in soil, but also at tree level in the oldest forests.This research was funded by Project FOREST-ECO2-Towards an Ecological and economic valorization of the Azorean Forest ACORES-01-0145-FEDER-000014-Azores 2020 PO, 2016-2019; FEDER funds through the Operational Programme for Competitiveness Factors-COMPETE and by National Funds through FCT-Foundation for Science and Technology under the UID/BIA/50027/2019 and POCI-01-0145-FEDER-006821info:eu-repo/semantics/publishedVersio

Gross primary production using related vegetation indices.

Site description; Micrometeorological and flux measurements; Hyperspectral reflectance measurements; Vegetation indexes