Search Results (271)

This study evaluated the performance of a recirculating aquaculture system (RAS) integrated with macroalgae (Ulva ohnoi) cultivation and sea urchin (Paracentrotus lividus) feeding, in a multi-trophic aquaculture approach. This system aimed to enhance sustainability through water bioremediation by macroalgae and valorization of the algal biomass as echinoderms feed. Over a 180-day trial, biomass production of U. ohnoi remained stable, with daily growth rates ranging from 7.4 to 24.4%. Statistical analyses (PCA and GAM) indicated no significant linear or non-linear relationship between macroalgae growth and environmental parameters (temperature, radiation, photoperiod). A theoretical estimate of nutrient production showed fairly stable values that do not statistically explain biomass production variation, highlighting the species’ adaptability. Sea urchins fed with fresh U. ohnoi showed regular growth, supporting the nutritional suitability of this macroalgae. For fish (Sparus aurata), no significant differences in growth or feed conversion ratio were observed between systems with and without algae. Parasitological monitoring revealed lower parasite loads and egg deposition in tanks in recirculation with U. ohnoi during certain periods, suggesting a potential role of macroalgae in reducing monogenean propagation. These findings underscore the feasibility of integrating Ulva cultivation into RAS, contributing to circular aquaculture models with improved sustainability and resource efficiency. Full article

Disease outbreaks pose a significant challenge in aquaculture, leading to substantial economic losses for producers. Tenacibaculosis, a significant ulcerative bacterial disease caused by Tenacibaculum maritimum, affects a wide range of marine fish species globally. Current disease management relies on antibiotics and chemicals, leading to environmental issues, impaired fish and consumer health, and increased antimicrobial-resistant bacteria. This narrative review critically explores welfare-oriented alternatives, specifically examining the potential of temperature modulation and functional diets. Although thermal strategies show promise for warm-water species through behavioural fever mechanisms, their effectiveness remains limited by species-specific thermal tolerances and lack of commercial validation. Nutritional interventions using marine algae, probiotics, and immunostimulants demonstrate broader applicability but suffer from inconsistent methodologies, limited commercial validation, and significant knowledge gaps. We propose that integration of these approaches could theoretically represent a paradigm shift from pathogen-focused to host-centred disease management, pending empirical validation. However, this integration concept requires rigorous validation, as significant knowledge gaps persists regarding optimal implementation protocols, welfare monitoring frameworks, and economic viability assessments. From our perspective, transitioning to welfare-oriented aquaculture demands rigorous evaluation and validation, commercial-scale trials, economic cost–benefit analysis, and the establishment of regulatory frameworks before these theoretical alternatives can be responsibly implemented. Full article

Climate change poses a significant challenge to agriculture in southern Angola, particularly for smallholder farming systems that are highly exposed and vulnerable, lacking the resources and capacity to respond effectively. This study analyses climate trends from 1950 to 2024 in Huíla, Namibe, and Cunene, focusing on eight variables: Tmax, Tmin, Tmean, PRCPTOT, R95p, R95pTOT, CDD, and CWD. Due to inconsistencies in local meteorological station data, ERA5-Land reanalysis was used. Trends such as rising Tmin in Namibe (+0.32 °C/decade), Tmean in Huíla (+0.16 °C/decade), and increased precipitation in Huíla (+29.3 mm/decade), along with fewer dry days in Namibe (–2.7 days/decade), were observed. Crop–climate relationships (2000–2023) were explored using a categorical contingency analysis. Maize showed its highest yield frequency (46%) during hot years; cassava and beans were more stable under cooler, drier conditions; millet yielded above average (31%) in dry years, confirming drought resilience; potatoes performed poorly in wet years (17% above-average yields). The contingency method provided insights where linear models were insufficient, helping to understand climate–yield interactions in data-limited environments. This study offers the first long-term climate–agriculture assessment for southern Angola, providing critical evidence for climate-informed agricultural strategies in regions with scarce and unreliable observational records. The findings emphasise the urgent need for adaptation policies focused on crop-specific climate vulnerabilities. They also demonstrate the value of combining reanalysis data and categorical analysis to overcome data gaps and guide sustainable agricultural planning. Full article

Companies are increasingly giving more attention to chatbots as an innovative solution to transform the customer service experience, redefining how they interact with users and optimizing their support processes. This study analyzes the acceptance of conversational robots in customer service within the insurance sector, using a conceptual model based on well-known new information systems adoption groundworks that are implemented with a combination of machine learning techniques based on decision trees and so-called importance–performance map analysis (IPMA). The intention to interact with a chatbot is explained by performance expectancy (PE), effort expectancy (EE), social influence (SI), and trust (TR). For the analysis, three machine learning methods are applied: decision tree regression (DTR), random forest (RF), and extreme gradient boosting (XGBoost). While the architecture of DTR provides a highly visual and intuitive explanation of the intention to use chatbots, its generalization through RF and XGBoost enhances the model’s explanatory power. The application of Shapley additive explanations (SHAP) to the best-performing model, RF, reveals a hierarchy of relevance among the explanatory variables. We find that TR is the most influential variable. In contrast, PE appears to be the least relevant factor in the acceptance of chatbots. IPMA suggests that SI, TR, and EE all deserve special attention. While the prioritization of TR and EE may be justified by their higher importance, SI stands out as the variable with the lowest performance, indicating the greatest room for improvement. In contrast, PE not only requires less attention, but it may even be reasonable to reallocate efforts away from improving PE in order to enhance the performance of the more critical variables. Full article

Alzheimer’s disease (AD) is the most common form of dementia, affecting over 50 million people globally. Since 1906, efforts to understand this neurodegenerative disease and to develop effective treatments have continued to this day. Recognizing docosahexaenoic acid (DHA, 22:6n-3) as a safe, inexpensive and vital nutrient for brain health and cognitive protection due to its key role in brain development and function, this study explores novel, sustainable non-fish sources as potential dietary supplements to prevent or mitigate AD, within a blue biotechnology framework. Forty 5×FAD male mice, five weeks old, were allocated to five body weight-matched dietary groups (n = 8) and fed isocaloric diets based on AIN-93M standard chow for 6 months. Each diet, except the control feed (non-supplemented group), enclosed a modified lipid fraction supplemented with 2% of the following: (1) linseed oil (LSO, rich in alpha-linolenic acid (ALA,18:3n-3)); (2) cod liver oil (fish oil, FO, rich in both DHA and eicosapentaenoic acid (EPA, 20:5n-3)); (3) Schizochytrium sp. microalga oil (Schizo) with 40% of DHA; and (4) commercial DHASCO oil (DHASCO) with 70% of DHA. The different diets did not affect (p > 0.05) growth performance criteria (e.g., final body weight, daily feed intake, and body weight gain) suggesting no effect on the overall caloric balance or mice growth, but n-3 long-chain polyunsaturated-fatty acid (n-3 LCPUFA) supplementation significantly reduced total cholesterol (p < 0.001) and total lipids (p < 0.001). No systemic inflammation was detected in 5×FAD mice. In parallel, a beneficial modulation of lipid metabolism by DHA-enriched diets was observed, with polyunsaturated fatty acid incorporation, particularly DHA, across key metabolic tissues, such as the liver (p < 0.001) and the brain (p < 0.001). No behavioural variations were detected using an open-field test after 6 months of diet (p > 0.05). While mice fed a standard diet or LSO diet showed cognitive deficit, the incorporation of FO, Schizo or DHASCO oils into dietary routine showed promising protective effects on the working memory (p < 0.05) and the last two diets also on the recognition memory (p < 0.05) Increased neuronal count (p < 0.05), reflecting neuronal survival, was clearly observed with the fish oil diet. In turn, the number of TAU-positive cells (p < 0.05) was reduced in the Schizo diet, while β-amyloid deposition (p < 0.01) and the neuroinflammatory marker, IBA1 (p < 0.05), were decreased across all DHA-enriched diets. These promising findings open new avenues for further studies focused on the protective effects of DHA derived from sustainable and underexploited Schizochytrium sp. microalga in the prevention of AD. Full article

The main objective of this study was the development of two semi-hard goat cheeses supplemented with Palmaria palmata and Ulva sp. with the aim of developing innovative food products, increasing the concentration of nutrients in these cheeses and familiarizing consumers with seaweed-containing foods. The impact of seaweed addition was evaluated through physicochemical, microbiological, and organoleptic properties of the semi-hard goat cheeses. Carbohydrate content was relatively low, whereas the total lipid content was relatively high (particularly in semi-hard goat cheese supplemented with seaweeds). Crude protein content presented higher values in semi-hard goat cheese supplemented with Ulva sp. The semi-hard goat cheese supplemented with Ulva sp. shows increased levels of Ca, Fe, Mn, and Zn. Instrumental color and the textural parameters of semi-hard goat’s cheese varied significantly with seaweed addition. Most of the microbiological load complies with the Portuguese (INSA) and the United Kingdom’s (HPA) guidelines for assessing the microbiological safety of ready-to-eat foods placed on the market. Additionally, the Flash Profile scores of semi-hard goat cheeses supplemented with seaweeds highlighted aroma and flavor complexity. Overall, this study confirms the potential of using seaweeds as a viable alternative to produce semi-hard goat cheeses with less pungency or goat milk flavor, making this product more pleasant and appealing to consumers sensitive to these sensory characteristics. Full article

This study focused on the carbonate system dynamics and air–sea CO₂ fluxes in the open-ocean waters of the Madeira–Tore Seamount Complex during August 2024. Surface water properties revealed pronounced latitudinal gradients in sea surface temperature (21.9–23.1 °C), salinity (36.2–36.7), and dissolved oxygen (228–251 µmol Kg⁻¹), influenced by mesoscale eddies and topographically driven upwelling. Despite oligotrophic conditions, distinct phytoplankton assemblages were observed, with coccolithophores dominating southern seamounts and open-ocean stations, and green algae and diatoms indicating episodic nutrient input. Surface total alkalinity (TA: 2236–2467 µmol Kg⁻¹), dissolved inorganic carbon (DIC: 2006–2183 µmol Kg⁻¹), and pCO₂ (467–515 µatm) showed spatial variability aligned with water mass characteristics and biological activity. All stations exhibited positive air–sea CO₂ fluxes (2.8–11.5 mmol m⁻² d⁻¹), indicating the region is a CO₂ source during summer. Calcite and aragonite saturation states were highest in stratified, warmer waters. Principal Component Analysis highlighted the role of physical mixing, carbonate chemistry, and biological uptake in structuring regional variability. Our findings emphasize and contribute to the complex interplay of physical and biogeochemical drivers in modulating carbon cycling and ecosystem structure across Atlantic seamounts. Full article

The need to maximize aquaculture production while addressing environmental and food security challenges posed by climate change has driven research towards the development of functional aquafeeds that enhance performance and immunity in farmed species. However, exposure to dietary and environmental stressors affects marine organisms, altering key metabolic pathways best understood through high-throughput “omics” tools. This study assessed the effects of Asparagopsis taxiformis supplementation on central metabolic pathways by analyzing changes in primary metabolite levels in the liver of farmed Diplodus sargus under optimal and suboptimal temperature conditions. Results showed that seaweed supplementation had a beneficial effect on the fish’s primary metabolome; however, inclusion levels and rearing conditions played a crucial role in determining outcomes. While 1.5% supplementation maintained a balanced primary metabolome under optimal temperature conditions, 3.0% supplementation most effectively mitigated the adverse effects of acute thermal stress during a marine heatwave. These findings highlight the nutritive and functional potential of A. taxiformis supplementation in aquafeeds for marine omnivorous fish species and emphasize the importance of evaluating functional aquafeeds under suboptimal rearing conditions. Overall, our results demonstrate the value of metabolomics in elucidating the molecular basis underlying biological pathways in farmed marine fish and optimizing production through climate-smart dietary strategies. Full article

This study investigates how persuasion, trust, and empathy from Human Resources (HR) managers affect the acceptance of nudging practices in workplace, especially when these interventions are meant to be ethical and supportive. Based on the theory of advisory nudge, the research connects ideas from Human Resource Management and ethical marketing. A quantitative method was applied using a structured questionnaire answered by 733 HR professionals in European companies. The model was tested with PLS-SEM, and results confirmed strong influence of supervisor’s persuasion and empathy on HR professionals’ perception of nudges as ethical and autonomy-enhancing. The findings also showed that empathy plays important role in how HR professionals experience the intention behind soft interventions, with gender-based differences being significant. Additional analyses with IPMA and MGA confirmed the strategic importance of trust and emotional intelligence in organizational settings. The results help to understand when a persuasive act is seen as ethical guidance and when it is not, offering theoretical and practical insights both for HR leadership and marketing communication. The study suggests future research to explore different types of nudging and include variables such as organizational culture or HR professionals’ values, to better understand the ethical acceptance of influence at work. Full article

This study explores how Human Resource Management (HRM) can help organizations to face the challenges of digital transformation, focusing on reducing digital inequalities and improving employee performance. As digital tools become more important in workplaces, many employees still experience digital exclusion, which affects not only their productivity but also their sense of fairness and inclusion, as well. To investigate these issues, quantitative research was conducted using a structured questionnaire distributed online to employees across EU-based companies. The data were analyzed through PLS-SEM, including IPMA and mediation analysis, to understand the relations between HRM practices, digital skills, and perceptions of organizational justice. The findings show that HRM strategies have a significant impact on bridging the digital divide, especially by promoting digital adaptability and supporting inclusive work environments. Inclusion was also found to mediate the relation between HRM and employee performance. This research offers practical suggestions, like using Key Performance Indicators (KPIs) to monitor digital participation and encouraging continuous learning. The study adds value by connecting digital empowerment with HRM policies in a way that supports both organizational efficiency and equality. Future research could focus on specific sectors or use longitudinal data to better capture how digital inclusion develops over time. Full article

Marine heatwaves (MHWs) are an emerging challenge for aquaculture, increasing the frequency and severity of disease outbreaks in farmed fish, weakening immunocompetence and compromising overall health and survival. As climate change stressors intensify, there is an urgent need for cost-effective and environmentally friendly strategies to enhance fish resilience. This study investigated the efficacy of Laminaria digitata, a brown macroalga, included in aquafeeds as powder (0.3% and 1.5%) or extract (0.3%) in improving the stress response of juvenile gilthead seabream (Sparus aurata) co-exposed to Vibrio harveyi infection during a category III MHW event. Under control conditions, L. digitata supplementation maintained or improved fish growth performance and overall well-being. After MHW exposure, the 1.5% powdered and 0.3% extract diets were more effective in mitigating thermal stress, reducing liver oxidative stress and lowering plasma cortisol levels. In infected fish, these diets improved resistance to V. harveyi, with reduced cortisol and alanine aminotransferase concentrations indicating hepatoprotective properties, and lower lipid peroxidation and decreased antioxidant enzyme activities reflecting an amplified capacity to counteract oxidative stress induced by inflammation. Overall, L. digitata is a promising aquafeed supplement, with the 1.5% powdered form offering a cost-effective alternative to the extract without compromising efficacy. Full article

Extreme weather events, such as marine heatwaves (MHWs), pose serious threats to the aquaculture sector, facilitating the occurrence of disease outbreaks and compromising farmed animals’ welfare and survival. Hence, finding eco-innovative strategies to improve animal immunocompetence is essential to assure aquaculture’s sustainability and resilience in a rapidly changing ocean. This study evaluated the immunostimulatory potential of Laminaria digitata powder (0.3% and 1.5%) and extract (0.3%) in juvenile gilthead seabream (Sparus aurata) exposed to a Vibrio harveyi outbreak during a Category III MHW event (T = 25.7 °C). Overall, L. digitata supplementation did not significantly affect fish immunocompetence under optimal rearing conditions (T = 21.4 °C; no infection), nor did it induce any adverse effects. However, both the powder (1.5%) and extract (0.3%) forms of L. digitata supplementation effectively mitigated the negative impacts prompted by the MHW and Vibrio harveyi infection—evidenced by improvements in fish health indicators, hematological parameters, leukocyte viability, granulocyte proportions, and reductions in peroxidase activity and immunoglobulin M levels. From an economic standpoint, supplementation with 1.5% L. digitata powder emerged as the most promising strategy, offering a practical balance between effectiveness and affordability for large-scale applications. These findings highlight the potential of L. digitata as an immunostimulatory aquafeed supplement, with promising benefits for fish health and resilience under adverse rearing conditions. Full article

This study investigates how inclusive leadership, mentorship, and digital tools shape conflict prevention and social cohesion within the Greek public sector. Employing a cross-sectional quantitative design, data were collected from 203 employees across municipalities, ministries, regional, and decentralized administrations. The survey instrument captured four dimensions: leadership and mediation for social cohesion, mentorship for the empowerment of vulnerable groups, use of digital tools, and the perceived social impact of inadequate conflict management. Data were analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM) to test direct and indirect effects, evaluate the explanatory and predictive power of the model, and explore the mediation mechanisms linking leadership, mentorship, and digital tools to social cohesion. The results demonstrate that both leadership and mentorship are positively perceived and significantly interrelated, jointly enhancing workplace cohesion and trust. Mentorship emerged as a critical predictor of digital tool adoption, highlighting its role as a bridge for digital inclusion and organizational innovation. In contrast, digital tools, despite their high importance in the model, remain underutilized and require further investment in training and integration. Poor conflict management is perceived as a major organizational risk, strongly linked to increased stress, diminished trust, and a deteriorated workplace climate. These findings highlight the value of integrating mentorship and inclusive leadership with mediation and digital technologies, supporting the development of hybrid strategies for conflict management. The study enriches theoretical debates on organizational resilience and social cohesion, while offering practical recommendations for modernizing public administration through participatory leadership, targeted mentoring programs, and the thoughtful adoption of digital solutions. Full article

The rapid shift to online education during the COVID-19 pandemic exacerbated mental health risks for students, particularly those experiencing multidimensional poverty—a potential contributor to psychological distress in digital learning environments. This study examines how poverty-driven techno-distress (technology-related stress) impacts university students’ mental health, focusing on 202 Chilean learners engaged in remote classes. Using partial least squares structural equation modeling (PLS-SEM), we analyzed multidimensional poverty and its association with techno-distress, measured through validated scales. The results suggest that poverty conditions are associated with 32.5% of technostress variance (R² = 0.325), while techno-distress may indirectly relate to 18.7% of students’ dissatisfaction with academic life—a proxy for emerging mental health risks. Importance–performance map analysis (IPMA) identified housing habitability (e.g., overcrowding, inadequate study spaces) and healthcare access as priority intervention targets, surpassing purely digital factors. These findings indicate that techno-distress in online education may function as a systemic stressor, potentially amplifying pre-existing inequities linked to poverty. For educators and policymakers, this highlights the urgency of early interventions addressing students’ physical environments alongside pedagogical strategies. By framing techno-distress as a public health challenge rooted in socioeconomic disparities, this work advances preventive approaches to safeguard student well-being in increasingly hybrid educational landscapes. Full article

The replacement of ingredients from animal sources with plant-based ingredients is increasing the risk of contamination by mycotoxins in aquafeeds, potentially causing detrimental effects on fish welfare. However, limited research has been carried out so far on the impact of mycotoxins on fish health. Hence, the aim of this study was to assess the toxicological effects of the dietary emerging (enniatin B, ENNB) and regulated (fumonisin B1, FB1) mycotoxins (150 µg/kg) in different tissues of juvenile gilthead seabream (Sparus aurata) after 28 days of dietary exposure. Fitness indexes, plasma metabolites, and biomarkers of oxidative stress, metabolism, cellular, and neurotoxic damage were assessed. The exposure to each mycotoxin was sufficient to cause distinct effects in fish tissues. ENNB appears to be the most harmful mycotoxin to S. aurata, inducing changes on alkaline phosphatase and lipase activities in plasma, as well as protein and lipid degradation in liver. Increased lipid degradation was also induced in the brain by FB1 alone or combined with ENNB, whereas the exposure to the mixture inhibited acetylcholinesterase activity. Overall, this study contributes by highlighting the toxicological attributes of ENNB, thus reinforcing the need to include this mycotoxin in future legislation. Full article