Sapientia
Repositório Científico da UAlg
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A note on varieties of ordered algebras
Publication . Clementino, Maria Manuel; Rodelo, Diana
The aim of this work is to study the notions of lax protomodular and Ord-Mal’tsev category at the level of (coherent) varieties of (pre)ordered algebras and to further compare them, as has been done in the non-ordered context. We characterise varieties of ordered algebras which are (co)lax protomodular and those which are Ord-Mal’tsev, in terms of operations of arities given by ordered sets and inequalities involving them. We exhibit examples of (co)lax protomodular non-degenerate Ordcategories, which were unknown. We prove that, for varieties of ordered algebras which are Ord-Mal’tsev categories, the order of their algebras is degenerate (i.e. is symmetric). As a consequence, the implication ``protomodular ⇒ Mal’tsev'' cannot be carried out to our context. The case of non-coherent ordered varieties which are Ord-Mal’tsev categories is also addressed, where we show the existence of algebras with non-degenerate order.
A Comunicação através das Rolhas de Cortiça – O Caso Português.
Publication . Carrasqueira, Helder
O objetivo deste estudo é estudar a comunicação presente nas mensagens insertas no cilindro da rolha de cortiça. Todos os anos, milhões de garrafas de vinho são vendidas tendo como vedante a rolha de cortiça. A sua principal função é preservar o vinho e manter a sua qualidade. Quem compra, compra o vinho; porém, quando abre uma garrafa, toma contacto com a rolha. Ela contém várias mensagens. O que dizem, a quem se destinam? Há uma estratégia de comunicação? Este é o cerne desta investigação. Faz-se uma análise qualitativa e quantitativa dos itens/mensagens de uma amostra de 220 rolhas selecionadas a partir de uma recolha de 537 unidades, representativas das regiões vinícolas nacionais; entrevista exploratória a profissional da comercialização de rolhas. Os resultados sugerem que as rolhas são um canal de comunicação com presença de elementos técnicos, boa representação da comunicação identitária (autenticidade, ligação ao terroir e identidade regional), mas ainda pouco explorado em termos de narrativa de comunicação dirigida ao consumidor ou referências à sustentabilidade. Estamos em crer que aqui reside o maior potencial de comunicação a explorar no futuro. A amostra limita-se a Portugal; sugerimos a extensão do estudo a outros países produtores, mas não encontrámos outros estudos/publicações científicas sobre esta temática.
Color-modulated spirulina biomass produced under heterotrophic cultivation as a sustainable food ingredient
Publication . Brito, Gabriela Moura Kurowiski de; Costa, Jorge Alberto Vieira; Barreira, Luísa; Morais, Michele Greque de
The intense green coloration of Spirulina biomass limits its incorporation into food products despite its high nutritional and bioactive value. This study evaluated the heterotrophic fed-batch cultivation of Spirulina sp. LEB 18 using glucose and sodium acetate, aiming to modulate biomass color and preserve a nutritionally relevant composition for its application as a food ingredient. After 10 days, all heterotrophic cultures exhibited attenuation of the green coloration, with total color differences greater than ΔE >7 relative to the controls. The reduction in chlorophyll a was consistent with the observed color changes, whereas phycocyanin and carotenoid contents did not differ significantly from the autotrophic controls. Cultivation supplemented with sodium acetate fed at 0.2 g L−1 showed a protein composition similar to the control and was the condition that exhibited the greatest color attenuation (ΔE = 10.33) without a pronounced reduction in protein content. Cultures supplemented with glucose resulted in higher lipid and carbohydrate accumulation, reflecting the redirection of carbon toward energy storage compounds. The results demonstrate that heterotrophic cultivation of Spirulina sp. LEB 18 is a promising strategy to modulate biomass color and composition, expanding its applicability, particularly in food matrices where green coloration limits consumer acceptance.
Dietary supplementation with algae-based ingredients modulates antioxidant defenses and immune response in sea urchin Paracentrotus lividus following a Vibrio parahaemolyticus challenge
Publication . Rodrigues, Ana Filipa; Lourenço, S.; Gomes, Ana Sofia; Vaz, M.; Cardoso, H.; Violante, A. P.; Baptista, T.
Functional diets are increasingly recognized as an important strategy to enhance health and production performance in sea urchin aquaculture. This study evaluates the effects of diets containing algae-based ingredients with different carotenoid pigment profiles on the immune and antioxidant systems of the sea urchin Paracentrotus lividus. During a 60-day nutritional trial, sea urchins were fed one of three diets that differed in both ingredient matrix and pigment profile: 1) a base diet formulated without algae and low in carotenoid pigments; 2) a formulated pumpkin/algal diet supplemented with Nannochloropsis sp. and high in β-carotene (nanno diet); and 3) a kelp diet based on Saccorhiza polyschides containing a mixture of carotenoid pigments and representing the natural diet of P. lividus. The effects of diets on oxidative stress response were assessed by quantifying catalase (CAT) and superoxide dismutase (SOD) activities and lipid peroxidation (LPO). The effect of diets on the short-term immune response was assessed using a time-course challenge with Vibrio parahaemolyticus at the end of the feeding trial. Sea urchins fed the kelp diet showed the strongest antioxidant defenses, while sea urchins fed the base diet presented higher LPO. After the pathogen challenge, total coelomocyte density was not significantly affected by diet. However, significant diet-dependent changes were observed in specific coelomocyte populations, including colorless granulocytes, red granulocytes and vibratile cells. Sea urchins fed the kelp diet exhibited a more pronounced immune activation, characterized by higher concentrations of lysozyme. In conclusion, supplementing diets with algae rich in carotenoids and other bioactive compounds may enhance sea urchin immune defenses against pathogens and improve resistance to oxidant stress. These findings support the development of functional diets for sea urchin aquaculture aimed at promoting health and resilience under culture conditions.
Levodopa and melanoma: practical recommendations for Parkinson's disease—international Parkinson and movement disorder society scientific issues committee viewpoint
Publication . Sciacca, Giorgia; Elsayed, Inas; Perez‐Lloret, Santiago; Outeiro, Tiago; Unni, Vivek K.; Kordower, Jeffery H.; Berg, Daniela; Kalia, Lorraine V.
The potential association between Parkinson's disease (PD), melanoma, and levodopa (l-dopa) use can be a source of uncertainty and concern in clinical practice. Several etiopathological hypotheses have been proposed, including a possible role of the protein α-synuclein that, in addition to being a major component of Lewy bodies in PD, is expressed in melanocytes.1 However, a definitive mechanistic link between PD and melanoma has yet to be defined. Epidemiological data examining whether l-dopa treatment increases melanoma risk in PD patients have been contradictory, and a causal connection has not been established. Nonetheless, product monographs for l-dopa-containing medications continue to cite a history of melanoma as a contraindication and list malignant melanoma as a potential adverse effect. This discrepancy between regulatory language and the available evidence can create uncertainty for both clinicians and people with PD when initiating or continuing l-dopa therapy. The aim of this article is to provide practical recommendations for clinicians based on current evidence regarding the (1) risk of melanoma in PD independent of l-dopa treatment based on epidemiological evidence and shared pathobiological mechanisms, (2) potential risk of developing melanoma with l-dopa use in PD, and (3) safety of l-dopa treatment in PD patients with a history of melanoma