Macroalgas da costa Açoriana : fonte de antioxidantes naturais

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.[...]. Um estudo realizado em 2012 na Universidade dos Açores por Paiva e colaboradores teve como objetivo a determinação da atividade antioxidante de oito das macroalgas mais comuns do litoral dos Açores, tendo em conta os baixos níveis de poluição da agua do mar e o potencial da sua utilização para o consumo humano e/ou para a extração de novos compostos de elevado valor acrescentado para as industrias alimentares e farmacêutica. Este estudo revelou que algumas macroalgas apresentam elevada atividade antioxidante, nomeadamente Fucus spiralis e Gelidium microdon. Fucus spiralis, conhecida como “tremoço do mar”, e tradicionalmente consumida por populações de algumas ilhas sendo considerada um petisco regional, e Gelidium microdon, conhecida como “musgão”, foi durante muito tempo utilizada para exportação e posterior produção de agar. […].info:eu-repo/semantics/publishedVersio

Multiscale model for the effects of adaptive immunity suppression on the viral therapy of cancer

Oncolytic virotherapy - the use of viruses that specifically kill tumor cells - is an innovative and highly promising route for treating cancer. However, its therapeutic outcomes are mainly impaired by the host immune response to the viral infection. In the present work, we propose a multiscale mathematical model to study how the immune response interferes with the viral oncolytic activity. The model assumes that cytotoxic T cells can induce apoptosis in infected cancer cells and that free viruses can be inactivated by neutralizing antibodies or cleared at a constant rate by the innate immune response. Our simulations suggest that reprogramming the immune microenvironment in tumors could substantially enhance the oncolytic virotherapy in immune-competent hosts. Viable routes to such reprogramming are either in situ virus-mediated impairing of CD$8^+$ T cells motility or blockade of B and T lymphocytes recruitment. Our theoretical results can shed light on the design of viral vectors or new protocols with neat potential impacts on the clinical practice.Comment: 14 pages, 4 figure

Contracting debt and the quality of financial reporting in private firms

This study investigates whether the quality of firms' financial reporting is influenced by the contracting of debt, using data on Portuguese private firms from 2013 to 2015. More specifically, the study uses earnings smoothing, magnitude of absolute discretionary accruals, and timeliness of disclosure as proxies for financial reporting quality. I find that private firms which contract more debt exhibit higher levels of financial reporting quality. Additionally, firms that contract larger amounts of debt and with a good financial performance tend to exhibit lower quality financial reporting. The results provide strong evidence that private firms have an interest in camouflaging their performance in the presence of higher levels of bank debt.info:eu-repo/semantics/publishedVersio

Charge-density waves in one-dimensional Hubbard superlattices

We study the formation of charge density waves (CDW's) in one-dimensional Hubbard superlattices, modeled by a repeated pattern of repulsive (U>0) and free (U=0) sites. By means of Lanczos diagonalizations for the ground state, we calculate the charge structure factor. Our results show that while the superlattice structure affects the modulation of the charge density waves, the periodicity can still be predicted through an effective density. We also show that, for a fixed repulsive layer thickness, the periodicity of the CDW is an oscillatory function of the free layer thickness.Comment: 4 pages, 4 figure

Limits of the energy-momentum tensor in general relativity

A limiting diagram for the Segre classification of the energy-momentum tensor is obtained and discussed in connection with a Penrose specialization diagram for the Segre types. A generalization of the coordinate-free approach to limits of Paiva et al. to include non-vacuum space-times is made. Geroch's work on limits of space-times is also extended. The same argument also justifies part of the procedure for classification of a given spacetime using Cartan scalars.Comment: LaTeX, 21 page

Análise do comportamento in vitro de explantes foliares de pequizeiro (Caryocar brasiliense camb.) através de RAPD.

xEdição de resumos do 7º Congresso Brasileiro de Fisiologia Vegetal, Brasília, 1999

Limits of space-times in five dimensions and their relation to the Segre Types

A limiting diagram for the Segre classification in 5-dimensional space-times is obtained, extending a recent work on limits of the energy-momentum tensor in general relativity. Some of Geroch's results on limits of space-times in general relativity are also extended to the context of five-dimensional Kaluza-Klein space-times.Comment: Late