25949 research outputs found
Sort by
Imidazolium polymerized ionic liquid-based membranes for the sustainable Cr(VI) recovery from industrial effluents
No full textThis study aimed to address the critical challenge of recovering chromate ions from industrial wastewater using stable functionalized membranes. We developed and evaluated the possibility of incorporating imidazolium-polymerized ionic liquids (PILs) into a polymeric matrix by using an original acrylate formulation to copolymerize a series of imidazolium-based PILs, thus chemically entrapping them within the membrane matrix. Notably, the PIL with the longest aliphatic chain produced dense, homogeneous membranes that were easy to manipulate and suitable for studies on Cr(VI) recovery. The resulting membrane enabled the quantitative recovery of chromate in a 0.1 M NaOH solution. Membrane stability was rigorously evaluated over 18 successive cycles (24 h each) and only a 20 % decrease in the recovery efficiency was observed, demonstrating reliable performance and the potential for repeated use despite exposure to the alkaline solution employed for chromate recovery. Importantly, the membrane required no regeneration or activation treatment, facilitating continuous Cr(VI) recovery through membrane permeation. Moreover, the effect of pH on the recovery efficiency of Cr(VI) was investigated in the range pH = 2–9, revealing a quantitative extraction for pH above 7. Selectivity experiments revealed the membrane's affinity for Cr(VI) extraction over Cr(III) and other metal ions in synthetic water mixtures. Furthermore, the imidazolium PIL-based membrane exhibited high efficiency (ranging from 63 % to 82 %) in recovering chromate from industrial wastewater samples, underscoring its practical suitability for environmental remediation. Overall, this study highlights the potential of PIL-based membranes as sustainable and efficient materials for water treatment applicationsOpen Access funding provided thanks to the CRUE-CSIC agreement with Elsevier
Beyond point predictions: Quantifying uncertainty in E. coli ML-based monitoring
No full textMachine learning regression models are increasingly used to improve management, decision-making, and monitoring of drinking water quality, leveraging growing data from real-time sensors and laboratory analyses. However, most models provide only point predictions, ignoring inherent uncertainty caused by unobserved factors that can produce varying outcomes under similar conditions. This study benchmarks state-of-the-art regression algorithms and uncertainty quantification methods for predicting E. coli concentrations in a drinking water catchment. Gradient-boosted decision trees (GBDT) proved effective for real-time tracking, with CatBoost achieving the lowest error (RMSLE = 0.877), improving on the naïve baseline (1.160) and outperforming Random Forest by 5 %. Uncertainty quantification techniques successfully generated valid prediction intervals to identify high-risk contamination events, with Conformalized Quantile Regression emerging as the most reliable method. By combining accurate GBDT predictions with well-calibrated uncertainty estimates, this approach enhances microbial water quality forecasting, offering improved risk assessment and supporting more robust decision-making in drinking water managementDavid Abert-Fernández thanks UdG for a predoctoral grant under the program IFUdG2023/2 and Hèctor Monclús gratefully acknowledges the Ramon y Cajal Research Fellowship (RYC2019- 026434-I). This study was supported ShERLOcK (PID2020-112615RA-I00) and WaterCLUE (CNS2023-143664) projects, financed by the Ministerio de Ciencia e Innovación (MICIN) and Agencia Estatal de Investigación (AEI) (Spain). LEQUIA has been recognized as a consolidated research group by the Catalan government (2021-SGR-1352).
Open Access funding provided thanks to the CRUE-CSIC agreement with Elsevier
Characterization of σ and π reaction channels in hydrogen atom transfer reactions
No full textC(sp3) –H bond activation mechanisms typically involve σ- and π-channel pathways, as characterized by FeOH (or FeOC) angles of ca. 180° and 120°, respectively. It is well known that the preference for either the σ- or π-channel depends on the spin state, but doubts exist on what would be characteristic values for the FeOX (X = H or C) angles. Here we study the oxidation of methane and ethane mediated by an Fe(IV)oxo model complex through density functional theory. A systematic comparison of dispersion-corrected B3LYP (B3LYP-D2, B3LYP-D3, B3LYP-D3BJ, B3LYP-D4) and the uncorrected counterpart (B3LYP) was conducted to evaluate the role of dispersion interactions in both gas and solvent phases. Our results reveal that dispersion corrections significantly influence barriers at transition states (TSs), particularly in the solvent phase, where dispersion contributions enhance stabilization of TS structures. The σ-channel pathway dominates for high spin (S = 2), while intermediate spin (S = 1) states favor the π-channel. Dispersion effects were found to be more pronounced for ethane, where larger non-covalent interactions between the substrate and Fe(IV)oxo complex arise. The FeOX angles vary substantially depending on the choice of dispersion correction, and between gas phase and solution phase. Indeed, for the reaction with ethane the FeOX values of the σ-channel approach values that are typically associated with the π-channel. Fortunately, the Spin-Resolved Charge Displacement Function provides a clear visual tool to distinguish the two channels. These insights advance the understanding of hydrocarbon functionalization by high-valent iron-oxo species, with implications for synthetic catalyst design in homogeneous and enzymatic catalysisThe authors acknowledge the generous support of the AEI/MCIN (grants PID2020-114548GB-I00 and PID2023-152415NB-I00 to M.S., JdC fellowship JDC2022-049287-I to M.A.), GenCat (grant 2021SGR00487, IF Fellowship 2022 FI_B 00118 to F.A.) and a developer's license to M.S. by Software for Chemistry and Materials (SCM). J. E. M. N. K. acknowledges funding from the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (VIDI grant VI.Vidi.223.108).
Open Access funding provided thanks to the CRUE-CSIC agreement with Elsevie
Metodología para estimar la Productividad Primaria Neta de agroecosistemas andinos y tropicales: adaptación al caso de Ecuador
No full textThis working paper presents a proposal to quantify the Net Primary Productivity (NPP) of crops, pastures, and forests within an Andean and tropical context. The methodology is based on the adaptation of Agrarian Metabolism for the case of Ecuador. The following sections provide the necessary information to estimate each land use, including the sources used, the calculations, and the required coefficients, which are detailed in the Annex. These conversion factors are adapted to the country's conditions to account for the real NPP of ecosystems and agroecosystems, which involves quantifying the total phytomass, both harvested and non-harvested, of aboveground and root parts. The methodology can be useful for similar for similar cases where official data sources may be limited, especially for the NPP of pastures and forests. Furthermore, it can be applied to both contemporary and historical studies, as it considers the transition from organic-based agriculture to an industrialized model. This is exemplified at the end of the document with the main results of the case studyEste documento de trabajo consiste en una propuesta para cuantificar la Productividad Primaria Neta (PPN) de cultivos, pastos y bosques en un contexto andino y tropical. La metodología se basa en la adaptación del Metabolismo Agrario para el caso de Ecuador. En los siguientes apartados se detalla la información necesaria para realizar la estimación de cada uso de suelo, esto es, las fuentes empleadas, los cálculos y también los coeficientes que se precisan, encontrándose estos últimos en el Anexo. Estos factores de conversión están adaptados a las condiciones del país con el fin de contabilizar la PPN real de los ecosistemas y agroecosistemas, lo que implica cuantificar toda la fitomasa, cosechada y no cosechada, de la parte aérea y de las raíces. La metodología puede servir sobre todo para casos similares donde haya límites en la disponibilidad de las fuentes oficiales, especialmente para la PPN de pastos y bosques. Además, puede aplicarse tanto para estudios del presente como en perspectiva histórica, ya que se considera el paso de una agricultura de base orgánica a una industrial. Esto se ejemplifica al final del documento con los principales resultados del caso de estudioEste trabajo se ha realizado gracias a la financiación del Ministerio de Ciencia, Innovación y Universidades para la Formación de Profesorado Universitario (FPU18/02315) y gracias también al proyecto de generación de conocimiento PID2021-123129NB-C42 del Plan Nacional de I+D de dicho Ministerio. Se agradece la información compartida por los miembros del LHA y por Álex Urrego1
La metodologia Montessori i l’observació com a eina per determinar millores en la capacitat de concentració: un estudi de cas en una escola infantil Montessori a Dinamarca
No full textAquesta recerca analitza el desenvolupament de la concentració en infants d'entre 4 i 6 anys dins d'un ambient Montessori a través de l'observació directa i l'ús de dues eines pedagògiques: la Fitxa d'Observació Individual i la Corba del Treball. Mitjançant un enfocament metodològic mix, s’ha observat a catorze infants durant diverses jornades per identificar patrons d'atenció, evolució al llarg del temps i tipologies d'activitats preferides segons l'edat. Els resultats apunten que l’ambient preparat Montessori, juntament amb l’autonomia de l’infant i la llibertat d’elecció, afavoreixen l’aparició d’estats de concentració profunda.This research analyzes the development of concentration in children between 4 and 6 years old within a Montessori environment through direct observation and the use of two pedagogical tools: the Individual Observation Sheet and the Work Curve. Using a mixed-methods approach, fourteen children were observed over several sessions to identify attention patterns, development over time, and preferred activity types according to age. The results suggest that the prepared Montessori environment, along with the child's autonomy and freedom of choice, facilitate the emergence of deep concentration states
Les cançons infantils tradicionals catalanes: d’avis a néts, de pares a fills, de mestres a infants… Que no es perdin!
No full textAquest Treball Final de Grau té com a objectiu promoure el coneixement sobre les cançons infantils tradicionals catalanes en l’àmbit escolar. Partint de l'observació que aquest repertori s'està perdent, s’analitza el coneixement mitjançant una metodologia d'investigació-acció basada en set sessions musicals per recuperar aquest patrimoni. L’estudi combina l'ensenyament de cançons tradicionals amb jocs manipulatius per desenvolupar la consciència fonològica. Els resultats han permès observar la importància d'incloure sistemàticament aquest patrimoni musical a l'aula, tant per preservar la identitat cultural com per enriquir els processos d'aprenentatge en aquesta etapa educativa.This Final Degree Project aims to promote knowledge about traditional Catalan children's songs in the school environment. Based on the observation that this repertoire is being lost, knowledge is analyzed through an action-research methodology based on seven musical sessions to recover this heritage. The study combines the teaching of traditional songs with manipulative games to develop phonological awareness. The results have allowed us to observe the importance of systematically including this musical heritage in the classroom, both to preserve cultural identity and to enrich the learning processes in this educational stage
Ballet i estereotips de gènere: conscienciació de la condició física del ballarí per minorar els estereotips de gènere en la dansa clàssica contemporània
No full textLa bibliografia mostra com l’educació física encara és una matèria que reprodueix estereotips de gènere, sent un d’aquests que hi ha activitats apropiades per a nois i d’altres per a noies. El ballet és una de les disciplines que es percep com a més estereotipada i feminitzada, a causa de l’èmfasi en el vessant estètic que se li ha atorgat i que sovint eclipsa les exigències físiques que requereix dansar. En canvi, els esports o activitats físiques que posen èmfasi en determinades condicions físiques, es conceben com apropiats per homes. És per aquest motiu que la present recerca té com a objectiu analitzar com la conscienciació sobre les condicions físiques d’un ballarí podria contribuir a reduir els estereotips de gènere en la dansa clàssica contemporània. Per a dur a terme l’estudi, s’utilitza un mètode quasiexperimental amb un grup mostra a qui se li administra tres instruments distribuïts en un pretest i un posttest per avaluar l'impacte de la proposta pedagògica DANCEFIT, composta per set sessions. Els resultats de la recerca afirmen que propostes pedagògiques com DANCEFIT, la qual s’inspira en el mètode BalletFit de Glòria Morales, orientades a fomentar la consciència sobre la condició física del ballarí contribuirien a reduir els estereotips de gènere vinculats a aquesta disciplina.The bibliography shows how physical education is still a subject that reproduces gender stereotypes, one of which is that there are activities appropriate for boys and others for girls. Ballet is one of the disciplines that is perceived as the most stereotyped and feminized, due to the emphasis on the aesthetic aspect that has been given to it and that often overshadows the physical demands that dancing requires. On the other hand, sports or physical activities that emphasize certain physical conditions are conceived as appropriate for men. It is for this reason that the present research aims to analyze how awareness of the physical conditions of a dancer could contribute to reducing gender stereotypes in contemporary classical dance. To carry out the study, a quasi-experimental method is used with a sample group who are administered three instruments distributed in a pretest and a posttest to evaluate the impact of the DANCEFIT pedagogical proposal, composed of seven sessions. The research results affirm that pedagogical proposals such as DANCEFIT, which is inspired by Glòria Morales' BalletFit method, aimed at promoting awareness of the dancer's physical condition would contribute to reducing gender stereotypes linked to this discipline
From Models to Meaning: Rethinking Writing Approaches in the Primary EFL Classroom
No full textThis study explores the effects of product-based and process-based writing approaches on the motivation and writing development of 26 fourth-grade EFL pupils at Escola Bellpuig. Implemented over six sessions within an eTwinning project, the intervention included structured letter writing and creative storytelling tasks. Data were collected through audio-recorded focus groups and analysed using the Critical Incident Technique. Results indicate that while students appreciated the clarity of product-based tasks, they felt more motivated and engaged with process-based writing. Many expressed a preference for a hybrid model, highlighting the value of combining structure and creativity to enhance writing skills and learner autonomy.Aquest estudi explora els efectes dels enfocaments d’escriptura basats en el producte i en el procés sobre la motivació i el desenvolupament de l’escriptura de 26 alumnes de quart de primària d’anglès com a llengua estrangera a l’Escola Bellpuig. La intervenció, emmarcada en un projecte eTwinning i desenvolupada al llarg de sis sessions, va incloure activitats d’escriptura estructurada de cartes i de creació de contes. Les dades es van recollir mitjançant grups focals enregistrats en àudio i es van analitzar amb la Tècnica dels Incidents Crítics. Els resultats indiquen que, tot i valorar la claredat de les tasques basades en el producte, els alumnes es van sentir més motivats i implicats amb l’escriptura basada en el procés. Molts van expressar preferència per un model híbrid, destacant la importància de combinar estructura i creativitat per afavorir l’aprenentatge de l’escriptura i l’autonomia de l’alumnat
Exploring the effectiveness of peer interaction dynamics in ESL oral communication activities
No full textThis study examines how English second language learners interact with their
peers during context-based oral communication activities, aiming to assess
whether peer interaction enhances children’s oral discourse abilities and supports
improved learning outcomes. Using a dynamic and interactive approach, three
targeted linguistic structures were introduced and practiced by 52 students with
varying levels of English proficiency. The results showed significant progress in
both learning outcomes and oral communication abilities. These findings highlight
the effectiveness of peer interaction as a strategy for fostering oral communication
skills and promoting overall second language acquisition.Aquest estudi analitza com els estudiants d’anglès com a segona llengua
interactuen amb els companys/es durant activitats de comunicació oral
contextualitzades, amb l’objectiu d'avaluar si aquesta interacció millora les seves
habilitats orals i resultats d’aprenentatge. A través d’ un enfocament dinàmic i
interactiu, 52 estudiants amb diferents nivells d’anglès van treballar tres
estructures lingüístiques. Els resultats van mostrar un progrés significatiu tant en
els resultats d’aprenentatge com en les habilitats de comunicació oral.Aquests
resultats demostren que la interacció entre iguals és una estratègia efectiva per
fomentar les habilitats orals i millorar l’adquisició d’una segona llengua
Formación de promotores de salud para el desarrollo de comunidades saludables = Training of Health Promoters for the Development of Healthy Communities
No full textIntroduction: health policies in Cuba currently address the impact of the training of health promoters on the development of healthy communities, requiring a diagnosis of the current state of the process. Objective: diagnose the status of the training process of health promoters for the development of healthy communities. Methods: qualitative study of the group interview type, at the University of Medical Sciences of Cienfuegos, Cuba, during September to December 2023, two focus groups were carried out each with nine students of the short-cycle nursing technician. Non-probabilistic theoretical sampling was used. The phases of development of group techniques were taken into account: setting objectives, selection of participants, preparation, organization, development of the topic, analysis of information and selection of the venue. Recording media were available. The participants in each group were identified with the letter "E" and "T". The narratives were transcribed and grouped to carry out content analysis, using a colorimeter technique, nuclei of meaning and weighted frequency were searched. Results: three categories emerged, "need for information", "material for the training of health promoters" and "necessary activities to carry out as health promoters". Thematic axes were analyzed: achievements in the training process, place given to young people, importance of the role of health promotion. Conclusions: the diagnosis aimed to strengthen and promote community participation in the promotion of healthy practices, which can have a positive influence on the health status of the populationIntroducción: Las políticas de salud en Cuba abordan, en la actualidad, la incidencia de la formación de promotores de salud en el desarrollo de comunidades saludables, requiriéndose diagnosticar el estado actual del proceso. Objetivo: Diagnosticar el estado del proceso de formación de promotores de salud para el desarrollo de comunidades saludables. Métodos: Se realizó un estudio cualitativo del tipo entrevista grupal, en la Universidad de Ciencias Médicas de Cienfuegos, Cuba, durante septiembre a diciembre del 2023, se realizaron dos grupos focales, cada uno con nueve estudiantes del Técnico Superior ciclo corto de Enfermería. Se utilizó muestreo teórico no probabilístico. Se tuvieron en cuenta las fases de desarrollo de las técnicas grupales: planteamiento de objetivos, selección de participantes, preparación, organización, desarrollo del tema, análisis de la información y selección del lugar de realización. Se contó con medios de grabación, Se identificaron con las letras “E” y “T” a los participantes de cada grupo. Las narrativas fueron transcritas y agrupadas para realizar el análisis de contenido, por técnica de colorímetro, se buscaron núcleos de sentido y frecuencia ponderada. Resultados: Emergieron tres categorías: “necesidad de información”, “material para la formación de promotores de salud” y “actividades necesarias a realizar como promotores de salud”. Se analizaron ejes temáticos: logros en el proceso de formación, lugar otorgado a los jóvenes, importancia del papel de la promoción de salud. Conclusiones: El diagnóstico apuntó a fortalecer y promover la participación comunitaria en la promoción de prácticas saludables, que puede tener influencia positiva en el estado de salud de la població