University of Cádiz
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Biotransformation of Thiochroman Derivatives Using Marine-Derived Fungi: Isolation, Characterization, and Antimicrobial Activity
Get PDFThiochroman derivatives are highly versatile molecules widely used for the synthesis of novel heterocycles and bioactive compounds. In our study, we conducted the biotransformation of thiochroman-4-ol (1) and 6-chlorothiochroman-4-ol (1a) using the marine-derived fungal strains Emericellopsis maritima BC17 and Purpureocillium lilacinum BC17-2. Biotransformations yielded ten known thiochroman derivatives along with the compound 1-(5-chloro-2-(methylthio)phenyl)propane-1,3-diol (6a), which was described for the first time. Moreover, we successfully characterized the stereoisomers of sulfoxides 3 and 3a. Their structures and absolute configurations were established though comprehensive analyses of NMR, HR ESI-MS, and ECD spectra, as well as by using Mosher’s method. Antimicrobial activity of the isolated metabolites was evaluated against bacterial and fungal human pathogens, specifically Staphylococcus aureus ATCC 29213, Escherichia coli ATCC25922, and Candida albicans HPM-1922816
First Records of Wild Octopus (Octopus vulgaris) Preying on Adult Invasive Blue Crabs (Callinectes sapidus)
Get PDFThe Atlantic blue crab, Callinectes sapidus, has rapidly expanded its invasive range ubiquitously in the Mediterranean Sea, posing ecological threats to native ecosystems. In its native habitat, the crab plays a crucial role in the ecosystem, but in invaded areas, it lacks natural predators. This has led to rapid expansion, highlighting the need to monitor and understand biological interactions with the native community. This study reports, for the first time in the wild, the predation of the invasive blue crab by the common octopus, Octopus vulgaris, in the Mediterranean Sea. Three sequences (two videos and a photography series) recorded by two spearfisherman (observation 1 and 2) and a recreational SCUBA diver (observation 3) are described. This article highlights the importance of native predators in influencing the expansion or control of invasive species. Additionally, it showcases the capacity of a versatile predator (the octopus), to serve as an ally alongside the fishing strategy, suggesting a novel perspective for ecologically sustainable management, in a context of low native predators of the blue crab. The collaboration with citizen scientists proves crucial in expanding our understanding of predator–prey dynamics and ecological interactions, underlining the need for continued partnerships between researchers and society for effective invasive species management
The Role of Surface {010} Facets in Improving the NOx Depolluting Activity of TiO2 and Its Application on Building Materials
Get PDFAir pollution, a major health concern, necessitates innovative solutions such as TiO2-based photocatalytic building materials to combat its harmful effects. This study focuses on developing high-performance TiO2 photocatalysts for NOx removal in building applications, aiming to overcome the limitations of commercial TiO2. These photocatalysts were synthesized via a hydrothermal method, with parameters such as synthesis time and post-treatment investigated to optimize their properties. Hydrothermal synthesis yielded TiO2 nanoparticles with reduced aggregation and a high proportion of elongated particles with exposed {010} facets. This resulted in significantly enhanced photocatalytic activity compared to commercial P25 in methylene blue degradation and NOx depollution. Subsequently, the optimized hydrothermal TiO2 was successfully integrated into a silica sol–gel coating for application on building materials. The coated concrete demonstrated significantly higher NOx removal efficiency and lower NO2 release, achieving a 1.7-fold improvement in overall NOx removal and significantly higher depolluting effectiveness compared to its P25 counterpart. These findings highlight the potential of hydrothermally synthesized TiO2 with controlled morphology for the development of high-performance, environmentally friendly building materials with enhanced air purification capabilities
Protecting privacy in the age of big data: exploring data linking methods for quasi-identifier selection
Get PDFThis paper explores the limitations faced by current solutions for selecting quasi-identifying attributes in the context of Privacy-Preserving Data Publishing (PPDP). PPDP stipulates that any published personal data should not be linkable to other available data sources in a manner that could potentially lead to individual re-identification or compromise sensitive data. The state-of-the-art methods for selecting quasi-identifying attributes commonly rely on heuristic evaluations to assess the risk of re-identification associated with each attribute. We hypothesize that these heuristic-based methods could be significantly improved by complementing them with empirical methods capable of quantifying the external linkability of dataset attributes. This empirical layer would enable a fine-tuning of the obfuscation of attributes within the dataset, thereby preventing the unnecessary privatization of attributes beyond potential attackers’ reach while ensuring privatization of those easily accessible. For this purpose, we explore recent advancements in identifying semantically related datasets across heterogeneous data sources. Although initially developed for purposes beyond privacy preservation, these methods support our initiative by uncovering potential links with external data and thus providing empirical evidence for the identification of attributes as quasi-identifiers. Finally, we discuss potential pathways to implement this empirical layer in quasi-identifier identification systems
Experimental validation of a simplified CFD model for a PCM-water finned heat exchanger
Get PDFThe most widely used numerical models in the scientific literature for simulating heat exchangers with phase change materials (PCMs) and water as the heat transfer fluid, are based on computational fluid dynamics (CFD) techniques, with the modelling of phase change being the key issue. The consideration of phase change effect, as well as the resolution of the movement of the PCM in the liquid state, make CFD models computationally very expensive. However, various published experiments indicate that during the heat discharge process, the dominant heat transfer mechanism is conduction in the solidified PCM around the finned tube. For this reason, this article presents a simplified CFD model, where convective flow of the PCM is neglected during the discharge process. The model was validated experimentally, and to achieve this validation process, an experimental prototype of a one-meter-long axially finned heat exchanger with four fins was built. Inlet and outlet water temperatures were continuously recorded, along with temperatures at various points inside the PCM, under four different water flow rates. The proposed numerical model was able to predict the outlet water temperature with an error smaller than 1◦C in all cases, and to capture the observed trend in temperature inside the PCM
Self-Medication Practice and Associated Factors Among Health Professionals in Spain
Get PDF(1) Background: Self-medication, defined as the use of medications without professional supervision, is a common practice that presents both potential benefits and significant risks. This study analyzes the prevalence, patterns, and determinants of self-medication among health professionals in Spain. (2) Methods: A cross-sectional descriptive design was employed with 438 health professionals, predominantly women (81.1%), with a median age of 42 years. The majority of the healthcare workers were nurses (45%). (3) Results: The results revealed a high prevalence of self-medication (59.4%). Analgesics and anti-inflammatory drugs were the most commonly used. Age and professional knowledge emerged as significant factors influencing this behavior. The main reasons for self-medication included the mildness of symptoms, easy access to medications, and previous successful experiences. Digital sources, especially websites, were the most consulted. Confidence in artificial intelligence tools as a clinical resource was moderate, with 18% of participants consulting AI tools, a rate comparable to the 19.5% for scientific databases. Logistic regression analysis identified age, knowledge of recommended doses, and perceived efficacy as significant predictors, while concern about risks acted as a protective factor. (4) Conclusions: This study highlights the need for educational interventions aimed at promoting responsible self-medication practices and mitigating associated risks among healthcare professionals
Is User Perception the Key to Unlocking the Full Potential of Business Process Management Systems (BPMS)? Enhancing BPMS Efficacy Through User Perception
Get PDFThis study investigates factors influencing employees' perceptions of the usefulness of Business
Process Management Systems (BPMS) in commercial settings. It explores the roles of system
dependency, system quality, and the quality of information and knowledge in the adoption and use
of BPMS. Data were collected using a structured questionnaire from end-users in various firms and
analyzed with Partial Least Squares (PLS). The survey evaluated perceptions of service quality, input
quality, system attributes, and overall system quality. The findings indicate that service quality, input
quality, and specific system attributes significantly influence perceived system quality, while system
dependency and information quality are predictors of perceived usefulness. The results highlight
the importance of user training, support, and high-quality information in enhancing satisfaction
and BPMS. This research offers empirical evidence on the factors impacting user perceptions and
acceptance, emphasizing the need for user-centric approaches in BPMS
Estudio experimental de soldaduras MAG y soldaduras híbridas (HLAW) en acero de alta resistencia s700mc
Get PDFEste estudio experimental analiza y compara diferentes técnicas de soldadura aplicadas al acero de alta resistencia S700MC, un material clave en la industria debido a su excelente relación resistencia-peso y su aplicabilidad en sectores como el offshore, la energía eólica y la fabricación de estructuras metálicas de alto rendimiento.
El trabajo se centra en tres procesos de soldadura: MAG, LBW y HLAW, evaluando sus ventajas, limitaciones y calidad de unión en función de diversos ensayos mecánicos y metalográficos. A través de un enfoque experimental, se han determinado los parámetros óptimos para mejorar la eficiencia y calidad de las soldaduras híbridas, con el objetivo de facilitar su implementación en entornos industriales exigentes.
Los resultados obtenidos en este estudio servirán como base para futuras investigaciones y optimización de procesos en soldadura de aceros avanzados, contribuyendo a la innovación y desarrollo de nuevas tecnologías de unión.Este trabajo de fin de grado se centra en el estudio de diferentes técnicas de soldadura aplicadas al acero de ultra alta resistencia S700MC, un material utilizado en sectores industriales exigentes como el offshore, torres eólicas y grúas telescópicas. Se analizan tres procesos de soldadura:
- MAG (Metal Active Gas), un proceso convencional de soldadura por arco con gas activo.
- LBW (Laser Beam Welding), que emplea un láser para unir las piezas sin aporte de materal.
- HLAW (Hybrid Laser Arc Welding), una combinación de soldadura por láser y arco eléctrico que mejora la penetración, velocidad y calidad del proceso.
El estudio experimental incluye pruebas en placas de acero de 8 mm de espesor utilizando la configuración Bead On Plate (BOP). Se han evaluado la calidad de las soldaduras mediante ensayos destructivos y no destructivos, como inspección visual, ensayos de tracción, pruebas de impacto Charpy, análisis metalográficos y medición de dureza.
El objetivo principal es optimizar los parámetros del proceso HLAW para obtener soldaduras de alta calidad y velocidad adecuadas para aplicaciones industriales. Los resultados obtenidos permitirán extender este conocimiento a configuraciones más complejas, como uniones a tope o en T, ampliando así las posibilidades de aplicación del acero S700M
REDIBAGG: Reducing the training set size in ensemble machine learning-based prediction models
No full textMachine learning-based algorithms have gained wide acceptance over the years due
to their high generalization capabilities for a wide range of classification applications.
Although these algorithms demonstrate potential and promising performance, they are
often limited by speed, particularly when training on large databases. Big data sets with many instances have storage requirements and execution times that can be excessive. This study proposes reducing the sample size generated by the bootstrap resampling method in Ensemble Machine Learning-based models and evaluates their generalization capability on unknown data. Reduced bootstrap samples are employed in the training phase of the Bagging ensemble model. This approach reduces execution times and, consequently, storage requirements. The proposed method was tested on classification tasks, effectively reducing training subset size without compromising performance. Experimental results demonstrate that this approach achieves execution times reductions of up to 70% for some data sets.
This reduction has no impact on accuracy, whereas maintaining levels comparable to classical Bagging and its variants. On average, the training subset size was reduced by 25% compared to the original size
El activismo en las escuelas desde la percepción de los futuros maestros y maestras de educación infantil
Get PDFEl activismo medioambiental se desvela como una acción educativa orientada a educar para la transformación social que permite ofrecer respuestas válidas al cambio global. En este contexto se apuesta por la agencia humana y como objetivo en este estudio nos preguntamos qué percepción tienen los futuros docentes de infantil sobre el activismo medioambiental. Para ello se pasó un cuestionario con preguntas semiestructuradas a una muestra de 54 futuros docentes de infantil. Los resultados fueron analizados a través del software NVIVO12. Los principales resultados muestran que el alumnado de magisterio de infantil valora positivamente el activismo en los centros educativos, aunque mantiene una visión muy polarizada en torno a su utilidad, la cual oscila desde considerarlo como un medio válido para que los estudiantes conozcan los problemas actuales (fin instrumental), a considerarlo como un movimiento y/o lucha por un cambio social (fin transformacional). Este trabajo contribuye a situar el activismo en la formación inicial del profesorado como un medio para garantizar acciones concretas orientadas a introducir un enfoque ecosocial en las escuelas y favorecer otras alternativas de contacto con la naturaleza