Sapientia
UAlg Scientific Repository
About Sapientia
SAPIENTIA brings together all scientific publications produced by teachers, researchers, and students (theses and dissertations) from the University of Algarve and cooperating entities (ULSALG-Unidade Local de Saúde do Algarve and Ciência Viva network centers in the Algarve) and aims to maximize their visibility, ensure easy access to this collection, improve the public impact of the scientific activity of the University and other entities, as well as ensure the preservation of their memories.
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Recent Submissions
Optimising resource utilisation in TNE franchise networks: a data envelopment analysis-based approach
Publication . Tran, Nguyen Hai Ngan; Dass, Rajinder; Amado, Carla; Pereira dos Santos, Sérgio
Purpose – Franchising programmes in higher education institutions (HEIs) face critical challenges in optimising resource use, enhancing productivity and ensuring effectiveness acrosstransnational networks. This study evaluates the performance of 18 franchise programmes within a single transnational higher education (TNE) network in three dimensions: admission efficiency, teaching efficiency and teaching effectiveness. Design/methodology/approach – Using a three-stage data envelopment analysis (DEA) model, this study examinesresource utilisation, efficiency-effectivenesstrade-offs and managerial performance gapsin businessrelated undergraduate programmes within a British university’s TNE network. The model enables internal benchmarking and real-world improvement mapping tailored to specific input–output dynamics. Findings – The results reveal marked performance heterogeneity, with only a single programme achieving maximumscores across all three dimensions.Admission efficiency emerged as a critical constraint, indicating room for scaling student recruitment without additional resources. Notable trade-offs across performance dimensions were identified, pushing for differentiated improvement strategies. High-performing programmes also serve as performance benchmarks, offering operational and managerial insight for cross-learning across the network. Originality/value – This study contributes to the performance management literature by creatively applying DEA within the specialised context of franchised TNE networks, a previously underexplored area in productivity research. It introduces a multidimensional staged DEA framework that captures efficiency– effectiveness trade-offs and supports performance benchmarking. Our findings contribute both theoretical advances in performance science and practical tools for academic network governance, offering actionable guidance for enhancing efficiency and effectiveness in TNE delivery systems.
Safe applications of ozone in tropical marine RAS: determining impacts of elevated total residual oxidants (TRO) on Stylophora pistillata and Xenia sp. holobionts
Publication . Weidlich, Sabine; Keuter, Sabine; Aires, Tania; Engelen, Aschwin; Kunzmann, Andreas
Ozone-aided treatment of seawater creates secondary oxidants, which can be toxic for aquaculture animals. We aimed to define safe limits of ozonation-derived total residual oxidants (TRO) for Stylophora pistillata and Xenia sp. by conducting a 96 h acute toxicity experiment. In a chronic exposure experiment we then determined the impacts of three sub-lethal levels of TRO on animal health over four weeks by monitoring respiration, net photosynthesis, photosynthetic efficiency, and three oxidative stress biomarkers (CAT, SOD, LPO). We further documented the changes in coral surface microbiomes exposed to elevated TRO with 16S rRNA amplicon gene sequence analysis. We showed that Xenia sp. is more susceptible to elevated TRO, with first mortalities occurring within 24 h at 0.188 mg L-1 and higher. In Stylophora, mortalities were observable within 24 h at 1.272 mg L− 1 and after 72 h at 0.353 mg L− 1 TRO. Sub-lethal TRO levels caused higher respiration and lower photosynthetic efficiency in Xenia, and increased catalase activity by 29–42 % in Stylophora and by 38–45 % in Xenia, while not impacting lipid peroxidation or superoxide dismutase activity. Microbiomes displayed TRO-induced changes in both species, with a decline in Saprospiraceae as a potential indicator for ozone-inflicted mucus layer degradation. Vibrionaceae fully disappeared from Stylophora pistillata microbiomes after 26 days of exposure to 0.131 mg L-1 TRO, suggesting ozonation as a potential tool to treat pathogens in coral aquaculture. Our study represents the first analysis of ozonation-induced impacts on coral holobionts, thereby providing a guideline for the safe application of ozone in coral cultivation.
Assessing the impact of gram-negative bacteria on the common octopus, in relation to rising sea temperature: a study of total protein concentration and hemolysis activity in hemolymph
Publication . White, Daniella-Mari; Karaveti, Emmanouela; Bakopoulos, Vasileios
Fish farming may pose a risk to adjacent octopus farms due to pathogen transmission. Moreover, the immune defense mechanisms of cephalopods are still not fully understood. This study aimed to determine changes in total protein concentration and hemolysis activity of Octopus vulgaris hemolymph, after intramuscular (IM) or intravenous (IV) challenges with aquaculture fish pathogens (either Photobacterium damselae subsp. piscicida or damselae or Vibrio alginolyticus or anguillarum O1) at two temperatures (21 ± 0.5 ℃ and 24 ± 0.5 ℃). Results showed that Octopus vulgaris exhibited a mean total protein concentration of 173.93 ± 69.37 mg/mL across all experimental conditions, markedly exceeding values reported for other mollusks, such as the bivalves Chamelea gallina (0.75–1.66 mg/mL) and Mytilus galloprovincialis (0.59–1.60 mg/mL). Patterns of total protein concentration, related to the genera of the pathogen used for the challenges, were observed. Four-way ANOVA revealed significant main effects of bacterium (F(3, 144) = 54.360, p < 0.001) and temperature (F(1, 144) = 10.014, p = 0.002) on total protein, along with multiple significant interaction effects, including bacterium × temperature, route × time, and bacterium × route × temperature × time (all p < 0.001). Hemolysis remained at low levels across both experimental temperatures, challenge routes, and pathogens, not exceeding 25 % in any case. Values above 15 % and up to 20 % were recorded in specific conditions, such as Photobacterium damselae subsp. damselae at 24 ± 0.5 ◦C on Day 3 in CIM-, IM-, and IV- control and challenged groups respectivelly; V. alginolyticus at 24 ± 0.5 ◦C on Day 3 in IM-challenged groups; and Vibrio anguillarum O1 at 21 ± 0.5 ◦C on Day 3 and Day 7 in IM-challenged groups. ANOVA for hemolytic activity showed significant main effects of bacterium (F(3, 144) = 22.032, p < 0.001) and temperature (F(1, 144) = 4.083, p = 0.045), with multiple significant interactions, including bacterium × temperature, route × time, and bacterium × route × temperature × time (all p < 0.001). These results indicate that the route of challenge may play a major role in hemolysis activity, with temperature and time post-challenge also exerting significant effects, possibly through a complex synergistic interaction. Our results may assist in elucidating common octopus defense mechanisms against common fish pathogens and provide important information to the scientific community and the marine aquaculture sector.
Bounding anisotropic Lorentz invariance violation from measurements of the effective energy scale of quantum gravity
Publication . Guerrero, Merce; Campoy-Ordaz, Anna; Potting, Robertus; Gaug, Markus
Observations of energy-dependent photon time delays from distant flaring sources provide significant constraints on Lorentz invariance violation (LIV). Such effects originate from modified vacuum dispersion relations causing differences in propagation times for photons emitted simultaneously from gamma-ray bursts, active galactic nuclei, or pulsars. These modifications are often parametrized within a general framework by an effective quantum gravity energy scale EQG;n. While such general constraints are well established in the LIV literature, their translation into specific coefficients of alternative theoretical frameworks, such as the Standard-Model extension (SME), is rarely carried out. In particular, existing bounds on the quadratic case (n ¼ 2) of EQG;n can be systematically converted into constraints on the nonbirefringent, CPT-conserving SME coefficients c ð6Þ ðIÞjm. This work provides a concise overview of the relevant SME formalism and introduces a transparent conversion method from EQG;2 to SME parameters. We review the most stringent time-of-flight-based bounds on EQG;n and standardize them by accounting for systematics, applying missing prefactors, and transforming results into two-sided Gaussian uncertainties where needed. We then use these standardized constraints, along with additional bounds from the literature, to improve bounds on the individual SME coefficients of the photon sector by about an order of magnitude. A consistent methodology is developed to perform this conversion from the general LIV framework to the SME formalism.
Polypharmacy and the Use of Potentially Inappropriate Medications in Elderly People in Nursing Homes: A Cross-Sectional Study
Publication . Fest, Giulia; Costa, Lara; Pinto, Ezequiel; Leitao, Helena; Nascimento, Tânia
Polypharmacy and the use of potentially inappropriate medications (PIM) are prevalent issues among institutionalized older adults, contributing to adverse drug events and decreased quality of life. This study aimed to describe the sociodemographic and clinical characteristics associated with polypharmacy and the use of PIM in elderly people in nursing homes. A cross-sectional descriptive study was conducted among 151 residents aged ≥ 65 years. Data was extracted from institutional records. The mean age of participants was 86.48 ± 8.00 years; 71.5% were female. Excessive polypharmacy was observed in 49.7% of residents. The mean number of medications was 9.66 ± 4.18, with nervous system drugs being the most prescribed (3.73 ± 2.31). PDDIs were detected in 94% of the sample and PIMs were present in 82.8% of residents. The most common PIMs were proton pump inhibitors (ATC A) and anxiolytics (ATC N). Binary logistic regression identified two independent predictors for PIMs: the total number of medications (AOR = 1.259) and the use of ATC A (Alimentary tract and metabolism) medications (AOR = 2.315). Conversely, age and sex were not significant predictors. The study reveals a critical prevalence of excessive polypharmacy, PIM use, and PDDIs among institutionalized elderly in the Algarve. These findings underscore the urgent need for systematic, multidisciplinary medication reviews in Portuguese nursing homes to promote safer and more rational prescribing practices.