Sapientia
Repositório Científico da UAlg
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An empirical model for non-linear pressure drag across non-hydrostatic flow regimes with trapped lee waves
Publication . Argain, Jose Luis
This study introduces a novel empirical model to estimate the total pressure drag generated by trapped lee waves (TLW) and upward-propagating internal waves in moderate-to-strong non-hydrostatic, stratified flow over a mountain ridge, as a function of flow non-linearity. The core framework is based on a two-layer atmosphere characterized by a piecewise-constant Scorer parameter, l, where a lower layer of constant l1 underlies an upper layer with l2<l1. This framework incorporates key features to extend beyond idealized assumptions, providing a reliable tool for predicting non-linear flow regimes over mountainous terrain, particularly those featuring realistic vertical profiles of the Scorer parameter. To develop the empirical formulation, a micro- to mesoscale numerical model is employed to simulate realistic, non-linear flows over steep topography. The proposed empirical model yields results that compare favorably with numerical simulations across a range of moderate-to-strong non-hydrostatic regimes, including complex cases derived from observational data and realistic vertical profiles of the Scorer parameter. The model demonstrates robust performance ranging from strongly to moderately non-hydrostatic regimes (the latter corresponding to dimensionless half-widths of approximately 5), and provides accurate drag estimates for non-linearities up to a dimensionless mountain height of approximately unity. Therefore, this empirical approach serves as a valuable foundation for improving drag parameterizations in weather prediction models, offering a computationally efficient alternative to high-resolution numerical downscaling over steep terrain.
A millennium-scale iberian margin chronology validates the 1755 Lisbon tsunami record and reveals faro record
Publication . Abrantes, Fatima; Domingues Gomes, Sandra; Salvado, Marta; Magalhães, Vitor; Salgueiro, Emilia; Drago, Teresa; Cordeiro, Lívia; Naughton, Filipa
This work presents new data and several age–depth reconstructions based on distinct approaches to improve previously published age models for sedimentary sequences collected on the Iberian Margin middle shelf: PO287 6-1B, 2G (Porto); PO287 26-1B, 3G, and D13902 (Lisbon); and POPEI VC2B (Algarve). The new age models are constructed using radiocarbon dates calibrated with the IntCal20 calibration curve and smooth-spline regressions from the CLAM (non-Bayesian) and Bacon (Bayesian) models. A comparison of the age–depth models generated by the different approaches shows that, beyond the distinct solutions produced by CLAM and Bacon for each site, the differences between the two methods are inconsistent across sites. Furthermore, neither model yielded reliable results for the discontinuous sedimentary sequence with reworked older sediments and a hiatus. In this specific case, the “classical” linear regression (best-fit) approach appears to yield the results that enable intercomparison across all sequences. This exercise confirms the record of the 1755 earthquake and tsunami in the Lisbon core splice and a potential record of the same event in the Eastern Algarve, although the collected data indicate a more distal or lower-energy wave deposit.
Assessment of cell disruption methods in an integrated multi-product biorefinery for Nannochloropsis Oceanica: from process design to economic analysis.
Publication . Cunha, Pedro; Carvalho, Bernardo; Kholany, Mariam; Pereira, Hugo; Varela, João
Microalgae are bioresources with significant potential within a sustainable, circular, bio-economy. However, high production costs have limited the widespread use of algae biomass. This study aimed to develop a multi-product biorefinery for Nannochloropsis oceanica that generates multiple revenue streams from the biomass, thereby enhancing the economic viability of algal production. The effectiveness of cell wall disruption using high-pressure homogenization and enzymatic hydrolysis was evaluated. Enzymatic hydrolysis solubilized nearly half (48.2 ± 1.5%) of the dry cell weight, compared to only 27.3 ± 3.2% with high-pressure homogenization, resulting in more concentrated water-soluble fractions and significantly higher protein extraction yields. Lipid extracts obtained after enzymatic hydrolysis had higher lipid (72.0 ± 5.3% w/w) and eicosapentaenoic acid (28.1 ± 6.9% w/w) contents than those from high-pressure homogenization (38.8 ± 6.1% w/w lipids; 9.1 ± 0.6% w/w eicosapentaenoic acid), despite similar lipid extraction yields (around 30%). Increasing the ethanol volumetric ratio from 58% to 75% v/v significantly improved lipid extraction yields (57.4 ± 3.1%) in the enzymatic hydrolysis-based biorefinery, with even higher yields observed upon scaling up (70.1%). All fractions, including lipid extracts, exhibited a balanced essential amino acid profile that exceeded the WHO/FAO/UNU-recommended values. A preliminary economic analysis indicated that lipid production was more cost-effective when cells were permeabilized by enzymatic hydrolysis than by high-pressure homogenization.
Ioga e qualidade de vida em pessoas idosas
Publication . Braz, Nídia Maria Dias Azinheira Rebelo; Pinto, Ezequiel; Shiliaeva, Elena
Este trabalho teve como objetivo verificar a
associação entre a prática de Ioga e a qualidade de
vida em pessoas idosas. Levou-se a cabo um
estudo transversal, correlacional, numa amostra
não-aleatória de 40 idosos de ambos os sexos, com
idades entre os 55 e os 80 anos, não
institucionalizados, residentes em diferentes
municípios do distrito de Faro, dividida em 2
grupos: praticantes de Ioga e não-praticantes.
Recolheram-se dados através de uma entrevista
semiestruturada que incluía questões sobre
variáveis sociodemográficas e as versões validadas
para português do Questionário de Qualidade de
Vida, da Escala de Depressão Geriátrica de
Yesavage e do Questionário Internacional de
Atividade Física. Analisaram-se os dados com o
programa Statistical Package for Social Sciences,
versão 28. Não se encontraram diferenças
estatisticamente significativas entre praticantes de
ioga e não-praticantes, exceto nas opiniões sobre
o ioga. Independentemente da experiência prévia
com o ioga, os par;cipantes, no geral, indicam que
esta prática pode ajudar durante o processo de
envelhecimento. Para os participantes, uma
qualidade de vida satisfatória significa estar
saudável, fisicamente ativo, ser autónomo, mas ter
um bom suporte social, ter oportunidade para
participar ativamente na vida social e manter o
bem-estar psicológico. De forma a analisar com
mais rigor a existência de alterações na qualidade
de vida e bem-estar associadas ao Ioga,
investigações futuras devem seguir um desenho
longitudinal, com uma amostra mais abrangente e
de maior dimensão.
Pitaya as a new alternative crop for Iberian Peninsula: cultural practices
Publication . Trindade, Ana Rita; Matias, Pedro; Lacerda, Vander; Pestana, Maribela; Tomás Marques, Natália; Duarte, Amilcar
Pitaya (Selenicereus spp.) cultivation has expanded in the Iberian Peninsula in recent years, driven mainly by increasing demand from the European market and by the crop’s good adaptability to Mediterranean conditions. However, the successful consolidation of this crop requires the adoption of cultural practices adapted to regional edaphoclimatic conditions and production systems. The present review aims to synthesise and critically analyse the scientific literature on pitaya cultural practices, integrating information from major producing regions worldwide and from Mediterranean environments, where data remain limited. Key topics include propagation methods for success in early development, training systems and pruning, soil management within the framework of sustainable orchard management practices and the crop’s versatility in integrating diverse agroecosystems. In addition, bibliometric analysis identified water requirements and irrigation strategies as key aspects for which region-specific guidelines are still required. This study emphasises the utilisation of floral induction techniques and the significance of supplementary manual pollination for ensuring higher productivity and superior fruit quality. Overall, this review provides a consolidated reference to support the development of sustainable and regionally adapted pitaya production systems in the Iberian Peninsula.