Browsing by Author "Moreira, Elsa"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Modelling drought classes time series for groundwater drought assessment and prediction in Algarve regionPublication . Moreira, Elsa; Neves, Maria C.Log-linear quasi-association models have been successfully applied to analyze and predict drought class transitions derived from standardized precipitation index (SPI) time series in Portugal. This kind of model proved to be suitable for fitting the SPI drought transitions and is considered a reliable tool for capturing the dynamics of drought severity changes since it models the probabilities associated with transitions in drought severity over specific time periods. In the context of groundwater drought monitoring, the standardized groundwater index (SGI) is used and is computed from groundwater levels available from the SNIRH piezometric network. The aim is to employ similar models to model the transitions between SGI drought classes and use them to analyze and predict transitions in groundwater drought classes one or two months in advance. The purpose is also to evaluate the effectiveness of these tools in predicting short-term transitions in groundwater drought. The findings contribute to improving water management practices and enhancing early warning systems to mitigate the impacts of drought in the Algarve, with potential applications in other parts of the world.
- Phenolic profile, antioxidant activity and enzyme inhibitory activities of extracts from aromatic plants used in Mediterranean dietPublication . Goncalves, Sandra; Moreira, Elsa; Grosso, C.; Andrade, Paula B.; Valentao, Patricia; Romano, AnabelaThe antioxidant and enzyme inhibitory properties of methanolic extracts from four aromatic plants used in traditional medicine and food [Calamintha nepeta (L.) Savi subsp. nepeta, Helichrysum italicum subsp. picardii Franco, Mentha spicata L. and Origanum vulgare subsp. virens (Hoffmanns. & Link) Bonnier & Layens] were evaluated. The extract from O. vulgare exhibited the strongest DPPH (IC50 of 4.65 +/- 0.12 mu g/ml) and ABTS (1479.56 +/- 12.29 mu mol(TE)/g(extract)) scavenging capacities, as well as the largest ferric reducing ability (1746.76 +/- 45.11 mu mol(AAE)/g(extract)). This extract also showed the highest total phenolic content (1597.20 +/- 24.10 mu mol(GAE)/g(extract)) and although HPLC-DAD analysis revealed rosmarinic acid as the main compound of the extract, other compounds seem to be involved in the antioxidant activity. Furthermore, the extract from H. italicum, which was found to be rich in caffeoylquinic and dicaffeoylquinic acids and in pinocembrin, showed the highest inhibitory potential against acetylcholinesterase, tyrosinase and alpha-glucosidase. Overall, the results obtained validate the usefulness of the studied plants as valuable sources of natural agents beneficial for human health.
- Using satellite data to monitor Groundwater drought in the Algarve regionPublication . Neves, Maria C.; Moreira, Elsa; Costa, LuisGroundwater drought presents significant economic and societal challenges, highlighting the need for effective monitoring and early warning systems at local and regional scales. Despite its vital role in water supply and irrigation, groundwater drought is often not adequately monitored in national operational systems. While the propagation of meteorological drought through hydrological systems has been extensively studied in various parts of the world, there is a lack of groundwater drought monitoring at an integrated basin-scale based on groundwater data. Long-term hydrological drought is often assessed using meteorological drought indices like SPI or SPEI with long periods of accumulation (12, 24 or 48 months time scales). However, most studies recognize that the accumulation periods necessary to achieve maximum correlation with groundwater observations exhibit high spatial variability due to the complexity of local hydrogeological conditions. This study aims to address this gap on groundwater drought monitoring in the Algarve by investigating the suitability of GRACE-based drought indices and ground-based drought indices derived from piezometer measurements for monitoring and predicting groundwater droughts.