Sapientia
UAlg Scientific Repository
Recent Submissions
Clustered patterns of household water consumption in Portuguese municipalities: do regional location and population trajectory matter?
Publication . Jacinto, Gonçalo; Barreira, Ana Paula
Portugal faces water scarcity challenges, yet studies on per-household water consumption are limited. This study aims to address this gap by employing cluster analyses to assess how population trajectories, a previously overlooked aspect, and the regional location influence per-household monthly water consumption across 122 municipalities. Findings highlight higher consumption in the South despite lower prices. Municipalities experiencing population growth and those with long-term population declines show higher per-household water consumption but lower prices. Interestingly, while higher prices correlate with lower consumption, southern municipalities show increased prices without reduced consumption. Clustering reveals slight changes in consumption patterns from 2011 to 2020.
Reconstruction of deep-water undercurrent variability from the outer Labrador Sea during the past 550,000 years
Publication . Kaboth-Bahr, Stefanie; Bahr, André; Blaser, Patrick; Voelker, Antje; Lippold, Jörg; Gutjahr, Marcus; Hodell, David A.; Channell, James E.T.; Vernal, Anne de; Hillaire-Marcel, Claude
We present a comprehensive multi-proxy analysis spanning 550,000 years from the outer Labrador Sea region at the Integrated Ocean Drilling Program (IODP) Sites U1302/1303. We combine new benthic foraminiferal stable oxygen (delta 18O) and carbon (delta 13C) isotope records, with sediment elemental composition and authigenic neodymium isotope measurements, to provide insights into deep-water mass sourcing and changes of the Deep Western Boundary Current (DWBC), which exports North Atlantic Deep Water (NADW) into the wider North Atlantic as part of the lower limb of the Atlantic Meridional Overturning Circulation. We find that a prominent DWBC likely remained a persistent feature within the Labrador Sea region throughout the past 550 kyr. However, glacial peaks of marine isotope stage (MIS) 14 to MIS 2 were consistently characterized by a weaker or shallower DWBC, while all interglacial periods of MIS 13a to MIS 1, with the exception of MIS 7e, were marked by enhanced DWBC. Additionally, the dominant deep-water masses feeding into the DWBC during these glacial-interglacial periods varied from regional (K-rich sediment, unradiogenic epsilon Nd) to more distal sources from the Nordic Seas (Ti-rich sediment, radiogenic epsilon Nd). Yet, these changes in deep-water provenance did not consistently correlate with DWBC strength, suggesting that additional factors may have played a significant role in shaping the DWBC strength or core depth throughout the geological past.
Within and beyond: chert pocurement patterns during the upper palaeolithic in Southwesternmost Iberia
Publication . Belmiro, Joana; Terradas, Xavier; Dominguez-Bella, Salvador; Cascalheira, João
Analyses of raw materials and the distinction between local/regional and long-distance sources have proven invaluable for understanding the extensive movements, interactions, and social networks during the Upper Palaeolithic in the Iberian Peninsula. However, unlike other parts of Iberia, research on the management and acquisition of raw materials in the south and west of Iberia remains relatively underdeveloped. Despite significant knowledge about the technological practices of Palaeolithic hunter-gatherers from southern Portugal, particularly from studies conducted at the site of Vale Boi, there is a noticeable lack of focus on raw materials management. This paper presents the first comprehensive characterisation of chert raw materials from the Gravettian, Proto-Solutrean, and Solutrean occupations at Vale Boi, using both macroscopic and petrographic techniques. Our study reveals that the majority of chert found at Vale Boi originates locally, within a 20 km radius. However, a non-negligible portion of the chert comes from non-local sources, indicating > 200 km raw material circulation from central Portugal and southern Spain.
Reasons for living and depressive symptomatology in young adults with and without suicide attempts: a moderated mediation approach
Publication . Brás, Marta; Martins, Cátia; Nunes, Cristina; Neves de Jesus, Saúl; Madeira, Ana Rita; Carmo, Cláudia
Introduction Suicide is a public health problem worldwide, being the fourth leading cause of death in young adult population (15-29 years). Therefore, it is important to identify its risk and protective factors, and how they interact to develop more effective interventions. The present study aims to analyze the relation between depressive symptoms, hopelessness (risk factors) with reasons for living (protective factors) and suicidal ideation in young adults with and without previous suicide attempts.Methods A sample of 845 Portuguese young adults answered an online form which assessed suicidal ideation, hopelessness, depressive symptoms, and reasons for living. Mean comparisons, correlations, and moderated mediation analysis were computed.Results Individuals with a history of suicide attempt showed higher mean levels in risk factors, compared to individuals without suicide attempt. When no history of suicide attempt was present, ideation was positively and significantly correlated to depression and hopelessness, and negatively correlated to the reasons for living. Higher levels of depressive symptomatology predict lower levels of reasons for living. Mediation and moderation relations were assessed in a model and the history of suicide attempts showed a relevant role.Conclusions The evidence found in this study reinforce that reasons for living may play a preponderant role in suicidal ideation, that is as a negative mediator and therefore it can act as a protective factor.
Enhancing efficiency in solar non-intrusive desalination: solar still prototype optimization in Southwest Europe
Publication . Pacheco, André; Sequeira, Claudia; Gomes Moreira da Silva, Manuela Fernanda; Serrão Sousa, Vânia
Access to freshwater is a pressing global challenge. Despite being irreplaceable freshwater is an increasingly scarce resource, especially in regions as Southern Europe, due to high human pressure and climate change. Solar desalination presents a low impact solution to produce freshwater from seawater, particularly in sun-rich regions. The main goal of this study was to develop a modular solar desalination system based on a non-intrusive approach, with simple assemblage, installation, and maintenance, to produce freshwater for non-potable purposes. The modular design was chosen to allow scalability and adaptability, enabling effective response to variable water demands in small island communities. The case study is a small island from Algarve, Portugal (Southwest Europe). The study evaluates the performance enhancements accomplished by transitioning from an initial prototype solar desalination unit, smaller and with a simple design, to an enhanced pilot-scale system designed to improve efficiency and water output. The research showed that both systems exhibit a high conductivity removal (higher than 99 %), demonstrating the potential of this technology to produce freshwater from seawater, delivering high-quality desalinated water, across different seasons. Prototype 1 demonstrated limited productivity, around 0.45 L/day.m2, while pilot-scale unit presented a productivity of approximately 6 L/day.m2 in summertime. This substantial improvement reflects the design modifications implemented in the pilot-scale unit, positioning it as a valuable option for water desalination in regions with abundant solar resources. These findings confirm the strong potential of solar desalination as a non-intrusive and effective solution and lays the groundwork for future advancements, focusing on maximising efficiency by exploring innovative materials to enhance solar energy absorption and optimizing operational conditions.