Browsing by Issue Date, starting with "2024-12-01"
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- Toxic and non-toxic cyanobacterial biomass as a resource for sustainable agriculture: A lettuce cultivation experimentPublication . Massa, Anabella; Santos, Érica; Martins, Diogo; Azevedo, Joana; Reimão, Mariana; Almeida, Agostinho; Azevedo, Rui; Pinto, Edgar; Vasconcelos, Vítor; Campos, Alexandre; Freitas, MarisaCyanobacteria represent a promising resource for sustainable agriculture, as they have demonstrated the ability to restore soil fertility even after death and decay. However, several cyanobacteria can also release secondary metabolites, such as cyanotoxins, which may compromise the quality of agricultural products and pose a potential risk to human health. Depending on the concentration of exposure, few studies reported deleterious effects on plant species when irrigated with cylindrospermopsin (CYN) contaminated water, impairing plant growth and leading to food product contamination, while other studies show promoting effects on plant yield. To evaluate the potential of cyanobacterial biomass (cyanotoxin-containing or not) as a sustainable resource for soil amendment, biostimulants or fertilizers for lettuce cultivation, a study was carried out that consisted of the culture of lettuce plants under controlled conditions, in soil: (1) with no extra nutrient addition (control) and supplemented with 0.6 g of freeze-dried Raphidiopsis raciborskii biomass of (2) a non-CYN-producing strain, (3) a CYN-producing strain, and (4) the same CYN-producing strain pasteurized. Results showed no significant differences in photosystem II efficiency with the amendment addition. On the contrary, shoot fresh weight significantly increased in lettuce plants grown with the cyanobacterial biomass addition, especially in condition (3). In addition, there were significant differences in mineral concentrations in lettuce leaves after the cyanobacterial biomass addition, such as K, Na, Ca, P, Mg, Mn, Zn, Cu, Mo, and Co. CYN accumulation was detected under conditions (3) and (4), with concentrations observed in descending order from roots > soil > shoot. Nevertheless, the CYN concentration in edible tissues did not exceed the WHO-proposed tolerable daily intake of 0.03 μg/kg/day. These findings suggest that incorporating cyanobacterial biomass as a soil amendment, biostimulant or fertilizer for lettuce cultivation, even with trace amounts of CYN (1–40 μg/g), may enhance plant yield without leading to cyanotoxin accumulation in edible tissues above the WHO-recommended tolerable daily intake.
- Tourism sector: evidence of business dynamics in PortugalPublication . Costa, Vânia; Pereira, Raquel; Loureiro, Isabel Sofia; Campinho, Sara; Moura, Andreia; Mira, Maria do Rosário; Silva, Goretti; Silva, SusanaAn in-depth understanding of the business dynamics of a given sector enables key stakeholders to define appropriate strategies for its development, promotion and consolidation. This study aims to analyse the Portuguese tourism and hospitality sector, characterising the companies and their business dynamics between 2011 and 2022. It uses a Related-Samples Friedman‘s Two-Way Analysis of Variance by Ranks to identify any statistically significant differences between the subsegments of Hotels and Restaurants, Recreational and Cultural Activities, and Transports and Logistics using specific competitiveness indicators. The results show significant differences between the subsegments in some indicators. The sector is resilient and plays a key role in recovering from highly impactful challenges. Micro and small companies employ thousands of people and make hotels and restaurants a key subsegment of activity for the sector. This study contributes to a comprehensive understanding of the dynamics of the tourism sector, providing valuable information to industry players and researchers.