Browsing by Issue Date, starting with "2024-09-03"
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- Microalgae as a selenium vehicle for nutrition: a reviewPublication . Pires, Rita; Costa, Margarida; Pereira, Hugo; Cardoso, Helena; Ferreira, Luís; Lapa, Nuno; Silva, Joana; Ventura, MárciaSelenium (Se) is essential for human and animal nutrition, playing a key role in antioxidant and immune functions. Organic Se is better for supplementation because it is more efficiently assimilated and less toxic than its inorganic form. Due to the scarcity of Se in European soils, supplementation in feed and food is necessary. Currently, inorganic Se (sodium selenite and selenate) and organic Se in Se-enriched yeast are approved by the European Food Safety Authority (EFSA) to address Se deficiency. However, Se-enriched microalgae present a promising alternative. By supplementing their growth media with Se, microalgae convert it into organic forms like Se-cysteine and Se-methionine, creating Se-enriched biomass. This biomass can serve as a valuable Se source with the additional benefits of microalgae. This review evaluates the viability of microalgae as a Se supplementation vehicle in food and feed and explores its commercial applications in the European Union (EU), along with emerging projects and innovations in the field.
- Underwater localization using time and frequency multiplexing of circular and spiral acoustic fieldsPublication . Viegas, Rúben S.; Zabel, Friedrich; Silva, António; Gomes, JoãoThe transmission of circular and spiral acoustic fields using spiral beacons offers a promising alternative to traditional underwater localization methods. Existing literature typically employs time multiplexing of these field types. This work introduces a novel approach by implementing both time and frequency multiplexing of circular and spiral fields, specifically transmitting three circular and one spiral field at distinct times and frequencies. The proposed multiplexing methods were evaluated at two different underwater environments: a controlled pool environment and a natural lagoon setting. The localization results demonstrate that the proposed method significantly reduces azimuth variability and confirms its functionality in a lagoon, although with less accuracy compared to the pool test. Overall, time and frequency multiplexing proved to be an effective strategy to enhance current spiral beacon systems and holds potential for advancing new underwater joint communication and localization techniques.